Youth's energy intake during a laboratory-based loss-of-control eating paradigm: Associations with reported current dieting

Dieting is theorized as a risk factor for loss-of-control (LOC)-eating (i.e., feeling a sense of lack of control while eating). Support for this association has largely relied on retrospective self-report data, which does not always correlate with objectively assessed eating behavior in youth. We hypothesized that during a laboratory-based LOC-eating paradigm, children and adolescents who reported current (at the time of the visit) dieting would consume meals consistent with LOC-eating (greater caloric intake, and intake of carbohydrates and fats, but less intake of protein). Participants were presented with a buffet-style meal and instructed to "Let yourself go and eat as much as you want." Current dieting (i.e., any deliberate change to the amount or type of food eaten to influence shape or weight, regardless of how effective the changes are) was assessed via interview. General linear models were adjusted for fat mass (%), lean mass (kg), height, sex, protocol, race and ethnicity, pre-meal hunger and minutes since consumption of a breakfast shake. Of 337 participants (Mage 12.8 ± 2.7y; 62.3 % female; 45.7 % non- Hispanic White and 26.1 % non-Hispanic Black; MBMIz 0.78 ± 1.11), only 33 (9.8 %) reported current dieting. Current dieting was not significantly associated with total energy intake (F = 1.63, p = .20, ηp2 = 0.005), or intake from carbohydrates (F = 2.45, p = .12, ηp2 = 0.007), fat (F = 2.65, p = .10, ηp2 = 0.008), or protein (F = 0.39, p = .53, ηp2 = 0.001). Contrary to theories that dieting promotes LOC-eating, current dieting was not associated with youth's eating behavior in a laboratory setting. Experimental approaches for investigating dieting are needed to test theories that implicate dieting in pediatric LOC-eating.

A randomized feasibility trial of medium chain triglyceride-supplemented ketogenic diet in people with Parkinson's disease

BACKGROUND

A ketogenic diet (KD) may benefit people with neurodegenerative disorders marked by mitochondrial depolarization/insufficiency, including Parkinson's disease (PD).

OBJECTIVE

Evaluate whether a KD supplemented by medium chain triglyceride (MCT-KD) oil is feasible and acceptable for PD patients. Furthermore, we explored the effects of MCT-KD on blood ketone levels, metabolic parameters, levodopa absorption, mobility, nonmotor symptoms, simple motor and cognitive tests, autonomic function, and resting-state electroencephalography (rsEEG).

METHODS

A one-week in-hospital, double-blind, randomized, placebo-controlled diet (MCT-KD vs. standard diet (SD)), followed by an at-home two-week open-label extension. The primary outcome was KD feasibility and acceptability. The secondary outcome was the change in Timed Up & Go (TUG) on day 7 of the diet intervention. Additional exploratory outcomes included the N-Back task, Unified Parkinson's Disease Rating Scale, Non-Motor Symptom Scale, and rsEEG connectivity.

RESULTS

A total of 15/16 subjects completed the study. The mean acceptability was 2.3/3, indicating willingness to continue the KD. Day 7 TUG time was not significantly different between the SD and KD groups. The nonmotor symptom severity score was reduced at the week 3 visit and to a greater extent in the KD group. UPDRS, 3-back, and rsEEG measures were not significantly different between groups. Blood ketosis was attained by day 4 in the KD group and to a greater extent at week 3 than in the SD group. The plasma levodopa metabolites DOPAC and dopamine both showed nonsignificant increasing trends over 3 days in the KD vs. SD groups.

CONCLUSIONS

An MCT-supplemented KD is feasible and acceptable to PD patients but requires further study to understand its effects on symptoms and disease.

TRIAL REGISTRATION

Trial Registration Number NCT04584346, registration dates were Oct 14, 2020 - Sept 13, 2022.

Deep phenotyping of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome

Post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS) is a disabling disorder, yet the clinical phenotype is poorly defined, the pathophysiology is unknown, and no disease-modifying treatments are available. We used rigorous criteria to recruit PI-ME/CFS participants with matched controls to conduct deep phenotyping. Among the many physical and cognitive complaints, one defining feature of PI-ME/CFS was an alteration of effort preference, rather than physical or central fatigue, due to dysfunction of integrative brain regions potentially associated with central catechol pathway dysregulation, with consequences on autonomic functioning and physical conditioning. Immune profiling suggested chronic antigenic stimulation with increase in naïve and decrease in switched memory B-cells. Alterations in gene expression profiles of peripheral blood mononuclear cells and metabolic pathways were consistent with cellular phenotypic studies and demonstrated differences according to sex. Together these clinical abnormalities and biomarker differences provide unique insight into the underlying pathophysiology of PI-ME/CFS, which may guide future intervention.

Neural underpinnings of threat bias in relation to loss-of-control eating behaviors among adolescent girls with high weight

Introduction

Loss-of-control (LOC) eating, a key feature of binge-eating disorder, may relate attentional bias (AB) to highly salient interpersonal stimuli. The current pilot study used magnetoencephalography (MEG) to explore neural features of AB to socially threatening cues in adolescent girls with and without LOC-eating.

Methods

Girls (12-17 years old) with overweight or obesity (BMI >85th percentile) completed an AB measure on an affective dot-probe AB task during MEG and evoked neural responses to angry or happy (vs. neutral) face cues were captured. A laboratory test meal paradigm measured energy intake and macronutrient consumption patterns.

Results

Girls (N = 34; Mage = 15.5 ± 1.5 years; BMI-z = 1.7 ± 0.4) showed a blunted evoked response to the presentation of angry face compared with neutral face cues in the left dorsolateral prefrontal cortex, a neural region implicated in executive control and regulation processes, during attention deployment (p < 0.01). Compared with those without LOC-eating (N = 21), girls with LOC-eating (N = 13) demonstrated a stronger evoked response to angry faces in the visual cortex during attention deployment (p < 0.001). Visual and cognitive control ROIs had trends suggesting interaction with test meal intake patterns among girls with LOC-eating (ps = 0.01).

Discussion

These findings suggest that girls with overweight or obesity may fail to adaptively engage neural regions implicated in higher-order executive processes. This difficulty may relate to disinhibited eating patterns that could lead to excess weight gain.

Associated features of pediatric loss-of-control eating severity during a laboratory-based feeding paradigm

Laboratory-based loss-of-control eating (LOC-eating; i.e., feeling like one cannot stop eating) paradigms have provided inconsistent evidence that the features of pediatric LOC-eating are consistent with those of DSM-5-TR binge-eating episodes. Thus, this study investigated whether recent LOC-eating (in the prior month) and/or greater LOC-eating severity during a meal are positively associated with faster eating rate, energy intake when adjusting for hunger, post-meal stomachache and sickness (a proxy for eating until uncomfortably full), depression, and guilt. Recent LOC-eating was assessed via interview. Participants were presented with a buffet-type meal and instructed to "Let yourself go and eat as much as you want." Immediately following, youth reported on their experience of LOC-eating during the meal (LOC-eating severity). Eating rate (kcal/min) was computed by dividing total energy intake by the duration of the meal. Prior to and following the meal, youth reported hunger, sickness, and stomachache via sliding Visual Analog Scales, depression via the Brunel Mood Scale and guilt via the PANAS-X. Three-hundred-ten youth participated (61.2 % Female; 46.3 % non-Hispanic White, 12.96 ± 2.72 y). Recent LOC-eating was not significantly associated with any DSM-5-TR binge-eating feature during the laboratory meal (ps = 0.07-0.85). However, LOC-eating severity during the meal was positively associated with eating rate, eating adjusted for hunger, post-meal sickness and stomachache, and guilt (ps < 0.045). LOC-eating severity during a laboratory-based feeding paradigm meal, but not recent LOC-eating, was associated with several features of DSM-5-TR binge-eating episodes. Future studies should assess multiple components of LOC-eating to further characterize the phenomenology of pediatric LOC-eating.

Investigating the use of local nerve blocks and general anaesthesia in reducing pain during and after disbudding procedure in goat kids

The aim of this study was to compare the pain responses (as measured by noise and movement) during administration of local anaesthetic and during and after disbudding in goat kids. Eighty, seven- to ten-day-old, Saanen goat kids from one farm were enrolled and randomly assigned to one of four different methods of pain relief. Twenty kids had local anaesthetic (LA) applied at two sites per horn bud (LA group), 20 kids had LA applied to the two locations using a jet injector (JI group) and 20 kids were given a general anaesthetic (GA) using a combination of 0.02 mg/kg medetomidine and 2 mg/kg ketamine followed by a horn bud block applied as per the LA group (GA group). The remaining 20 kids had no treatment other than meloxicam (control group). Although responses between goat kids and at different time periods were variable, in comparison to the control group, GA eliminated the responses associated with injection of lignocaine and the responses during the period of disbudding, and provided a reduction in head scratches and shakes across multiple time periods.

Associations of Food Reinforcement and Food- Related Inhibitory Control with Adiposity and Weight Gain in Children and Adolescents

Some, but not all studies have reported that, among youth with disordered eating and high weight, the relative reinforcing value of food (RRV-F, i.e., how hard a person will work for a high-energy-dense food when another reward is available) is greater, and food-related inhibitory control (i.e., ability to withhold a response to food-related stimuli) is lower, compared to peers without disordered eating or overweight. In most studies, high RRV-F and low food-related inhibitory control have been studied separately, as independent factors, with each suggested to predict excess weight and adiposity (fat mass) gain. We hypothesized that the interaction of these factors would prospectively exacerbate risk for weight and adiposity (fat mass) gain three years later in a sample of healthy youth. At baseline, RRV-F was measured using a Behavior Choice Task with the rewards being standardized servings of chocolate candies, cheese crackers, or fruit snacks. Food-related inhibitory control was determined by performance in response to food and non-food stimuli during a Food Go/No-Go task. At baseline and 3-year visits, total body adiposity was measured by dual-energy X-ray absorptiometry (DXA) and body mass index (BMI) was obtained using measured weight and height. A linear regression was conducted with 3-year adiposity as the dependent variable. RRV-F, food-related inhibitory control, and the RRV-F x food-related inhibitory control interaction as independent variables. Baseline adiposity, age, height, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year adiposity. Baseline BMI, age, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year BMI. One-hundred and nine youth (mean 12.4±2.7y, mean 0.50±1.02 BMIz, 30.3% with overweight/obesity, 45.9% female, 51.4% non-Hispanic White), 8-17 years at baseline, were studied. Baseline food-related inhibitory control (β_{unstandardized} = .33, p = .037, 95% CI [.02, .64]), but not baseline RRV-F (β_{unstandardized} = -.003, p = .914), 95% CI [-.05, .05]) was significantly associated with 3-year adiposity such that those with the lowest food-related inhibitory control had the greatest adiposity gain. The interaction between RRV-F and food-related inhibitory control did not predict 3-year adiposity (β_{unstandardized} = -.07, p = .648, 95% CI [-.39, .25]). The pattern of findings was the same for models examining non-food related inhibitory control. Neither baseline food-related inhibitory control (β_{unstandardized} = 2.16, p = .256, 95% CI [-1.59, 5.92]), baseline RRV-F (β_{unstandardized} = .14, p = .660, 95% CI [-.48, .75]), nor their interaction (β_{unstandardized} = -1.18, p = .547, 95% CI [-5.04, 2.69]) were significantly associated with 3-year BMI. However, non-food related inhibitory control (β_{unstandardized} = .54, p = .038, 95% CI [.22, 7.15]) was significantly associated with 3-year BMI. In summary, food-related inhibitory control but not RRV-F, was associated with changes in adiposity in a sample of children and adolescents. Among generally healthy youth, food-related inhibitory control may be a more relevant risk factor than food reinforcement for adiposity gain. Additional data are needed to determine how impulsivity and reward systems, as well as other disinhibited eating behaviors/traits, may interact to promote excess weight gain over time in youth.

The effects of prebiotics on gastrointestinal side effects of metformin in youth: A pilot randomized control trial in youth-onset type 2 diabetes

Disclosure summary

Dr. Yadav is Chief Scientific Officer and Co-Founder of Postbiotics Inc and has no conflict of interest with this work. All other authors have no conflicts of interest to disclose.

Background

Metformin is the only approved first-line oral glucose lowering agent for youth with type 2 diabetes mellitus (Y-T2DM) but often causes gastrointestinal (GI) side effects, which may contribute to reduced treatment adherence and efficacy. Prebiotic intake may reduce metformin's side effects by shifting microbiota composition and activity.

Objective

The aims of this study were to determine the feasibility and tolerability of a prebiotic supplement to improve metformin-induced GI symptoms and explore the changes in glycemia and shifts in the microbiota diversity.

Methods

In a two-phase pilot clinical trial, we compared, stool frequency and stool form every 1-2 days, and composite lower GI symptoms (weekly) at initiation of daily metformin combined with either a daily prebiotic or a placebo shake in a 1-week randomized double-blind crossover design (Phase 1), followed by a 1-month open-labeled extension (Phase 2). Plasma glycemic markers and stool samples were collected before and after each phase.

Results

Six Y-T2DM (17.2 ± 1.7y (mean ± SD), 67% male, BMI (42 ± 9 kg/m2), HbA1c (6.4 ± 0.6%)) completed the intervention. Stool frequency, stool composition, and GI symptom scores did not differ by group or study phase. There were no serious or severe adverse events reported, and no differences in metabolic or glycemic markers. After one week Phase 1metformin/placebo Proteobacteria, Enterobacteriaceae, and Enterobacteriales were identified as candidate biomarkers of metformin effects. Principle coordinate analyses of beta diversity suggested that the metformin/prebiotic intervention was associated with distinct shifts in the microbiome signatures at one week and one month.

Conclusion

Administration of a prebiotic fiber supplement during short-term metformin therapy was well tolerated in Y-T2DM and associated with modest shifts in microbial composition. This study provides a proof-of-concept for feasibility exploring prebiotic-metformin-microbiome interactions as a basis for adjunctive metformin therapy.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT04209075.

Dietary Intakes of Patients with Alcohol Use Disorder During a 4-Week Protocol on an Inpatient Treatment Unit Found to Meet Dietary Reference Intakes for Macronutrients, but Have Variability in Energy Balance and Adequacy of Micronutrient Intake

BACKGROUND

Despite literature supporting the importance of diet during rehabilitation, minimal research quantifies dietary intake during treatment for alcohol use disorder (AUD).

OBJECTIVE

The aim was to quantify dietary intake and energy balance of patients with AUD during inpatient treatment.

DESIGN

This was a secondary analysis of data from a 4-week observational protocol. Participants self-selected food from a room service menu. Dietary intake was recorded by patients and reviewed by nutrition staff. To quantify nutrient and food group intake, data were coded into Nutrition Data Systems for Research software, versions 2016 and 2017. Daily average intake was calculated for all dietary variables.

PARTICIPANTS/SETTING

Participants (n = 22) were adults seeking treatment for AUD at the National Institutes of Health Clinical Center (Bethesda, MD) between September 2016 and September 2017 and who were enrolled in a study examining the microbiome during AUD rehabilitation. Four participants discontinued protocol participation before study week 4 and were not included in analyses examining change over time.

MAIN OUTCOME MEASURES

Weight change, daily energy, and macronutrient and select micronutrient intakes were the main outcome measures included.

STATISTICAL ANALYSES PERFORMED

Mean differences in intake and weight were assessed using nonparametric tests.

RESULTS

Sixty-four percent of participants were male; mean ± SD age was 46.3 ± 13.0 years, mean ± SD body mass index (calculated as kg/m2) was 23.9 ± 2.5, and mean intake was 2,665 kcal/d (consisting of 45.9% carbohydrate, 34.9% fat, and 19.1% protein). Eighty percent or more of this sample met the Estimated Average Requirement for 10 of 16 micronutrients assessed. Male participants consumed more energy than estimated needs (P = .003) and gained a mean ± SD of 2.67 ± 1.84 kg (P = .006) when an outlier with weight loss and acute pancreatitis was removed from analysis. Female participants did not gain weight or consume more than estimated energy needs.

CONCLUSIONS

Overall macronutrient intake was within recommended ranges, but intake of other dietary components and weight gain were variable, supporting the need for individualized nutrition care during AUD treatment.

LBODP002 Phase II Open-label Pilot Trial Of Liraglutide In Adolescents With Obesity After Vertical Sleeve Gastrectomy: Interim Results From 8-weeks Of Treatment

Background

Metabolic and bariatric surgery (MBS) is currently the most effective weight loss treatment in adults and children with severe obesity. However, up to 50% of adolescents continue to have obesity three years post-MBS. Vertical sleeve gastrectomy (VSG), the most common MBS performed in adolescents, causes an increase in post-prandial glucagon-like peptide 1 (GLP-1) post-operatively, but the duration of this incretin hormone response is unclear. Liraglutide, a GLP-1 analogue, may supplement the physiological increase in GLP-1 following VSG and promote weight loss via appetite suppression. We hypothesized that daily liraglutide treatment would significantly reduce body weight in adolescents who had previously undergone VSG but who continued to have insufficient weight loss. This abstract reports interim data from our prospective clinical trial of liraglutide in adolescents with obesity after VSG (ClinicalTrials.gov Identifier: NCT04883346).

Methods

This trial is an active, open-label, phase II pilot study to investigate the efficacy of daily subcutaneous liraglutide to promote reduction of BMI in adolescents with persistent obesity 1 year or more after VSG. The primary objective is to determine the effect size for the change in BMI of liraglutide 3. 0 mg daily at 16 weeks in study participants to calculate the sample size of a subsequent randomized controlled trial. Inclusion criteria are age 12 to 20.99 years, good general health, BMI≥30 kg/m2, and a personal history of VSG ≥1-year prior. Exclusion criteria include major medical illnesses, use of medications associated with weight gain, or use of weight-loss medications within the last 3 months of screening. Liraglutide is initiated at 0.6 mg daily and escalated by 0.6mg weekly to 3 mg/d for the last 12 weeks of treatment. Participants receive monthly nutrition counseling throughout the study.

Results

At time of interim analysis (3/24/22), 26 participants (baseline age 18±1.9y, mean±SD; 65% female; 55% black; baseline BMI 42. 0±7. 0 kg/m2) were screened and 20 started liraglutide. Among 17 participants who reached 8 weeks of treatment, mean absolute change in weight was -3.9±2.6 kg, percent change in weight was -3.6±2.6%, absolute change in BMI was -1.4±0.9 kg/m2, and percent change in BMI was -3.6±2.6%. There were no serious treatment-emergent adverse events (TEAEs) reported; 16/20 participants reported non-serious TEAEs including low energy (40%), nausea (40%), and vomiting (20%). In this interim analysis of an open-label phase II pilot study, the mean weight change from baseline was -3.6% after 8 weeks of liraglutide treatment in adolescents with persistent obesity after VSG. No new TEAEs were identified. Completion of this study will help determine if weight reduction with liraglutide suggests value to carry out a randomized placebo controlled study using liraglutide.

Presentation: No date and time listed

Heart Rate Variability and Laboratory-Based Loss-of-Control Eating in Children and Adolescents

Among youth, greater heart rate (HR) and lesser HR variability (HRV) are precursors to loss-of-control (LOC) eating episodes in the natural environment. However, there are limited data examining whether pre-meal HR and HRV are associated with greater LOC-eating in the laboratory setting. We therefore examined temporal relationships between pre-meal HR, frequency- and time-based metrics of pre-meal HRV, perceived LOC-eating, and energy intake during a meal designed to simulate a LOC-eating episode. Among 209 participants (54.5% female, 12.58 ± 2.72 years, 0.52 ± 1.02 BMIz), 19 reported LOC-eating in the prior month. Perceived LOC-eating during the laboratory meal was not significantly linked to pre-meal HR (p = 0.37), but was positively related to pre-meal HRV (ps = 0.02–0.04). This finding was driven by youth with recent LOC-eating, as these associations were not significant when analyses were run only among participants without recent reported LOC-eating (p = 0.15–0.99). Pre-meal HR and HRV were not significantly related to total energy intake (ps = 0.27–0.81). Additional research is required to determine whether early-stage pediatric LOC-eating is preceded by a healthy pre-meal stress response. Longitudinal studies could help clarify whether this pattern becomes less functional over time among youth who develop recurrent LOC-eating episodes.

Comparison of Three Anaesthetic Options to Reduce Acute Pain Response in Kid Goats

Three options for anesthetizing the skin around the horn bud of dairy goat kids were explored. Forty-five <10-day-old Saanen goat kids from were randomly split into five treatment groups (topical anesthetic cream (TA), vapocoolant spray (VS), local anesthetic applied by jet injector (JI), control - no treatment but painful stimulus applied (C), sham - no treatment and touching sites with a finger. The painful stimulus was multiple needle pricks on the skin around the horn bud. The outcome variables measured were heart rate movement, and vocalization during treatment application and administration of a painful stimulus around the horn bud. Heart rates were greater during application of a VS compared to TA.Neither the TA nor the VS appeared to have any effect on the response to the painful stimulus. Kids in the JI group had a 96% reduced odds of expressing a marked pain response in comparison to TA group and an 83% reduction in the odds of a high movement grade during a painful procedure in comparison to the combined results of the other three treatment groups.

Ketogenic diet reduces alcohol withdrawal symptoms in humans and alcohol intake in rodents

Individuals with alcohol use disorder (AUD) show elevated brain metabolism of acetate at the expense of glucose. We hypothesized that a shift in energy substrates during withdrawal may contribute to withdrawal severity and neurotoxicity in AUD and that a ketogenic diet (KD) may mitigate these effects. We found that inpatients with AUD randomized to receive KD (n = 19) required fewer benzodiazepines during the first week of detoxification, in comparison to those receiving a standard American (SA) diet (n = 14). Over a 3-week treatment, KD compared to SA showed lower "wanting" and increased dorsal anterior cingulate cortex (dACC) reactivity to alcohol cues and altered dACC bioenergetics (i.e., elevated ketones and glutamate and lower neuroinflammatory markers). In a rat model of alcohol dependence, a history of KD reduced alcohol consumption. We provide clinical and preclinical evidence for beneficial effects of KD on managing alcohol withdrawal and on reducing alcohol drinking.

Feeding synthetic zeolite to transition dairy cows alters neutrophil gene expression

Synthetic zeolites are used to control the availability of dietary minerals (e.g., Ca, Mg, and P) in dairy cows. Due to calcium demand increasing with lactation onset, most cows become hypocalcemic immediately postpartum, which likely contributes to poorer immune function because calcium is important for immune cell signaling. To overcome postpartum hypocalcemia, we fed transition cows synthetic zeolite A (sodium aluminosilicate) precalving and hypothesized that it would alter calcium and thus neutrophil function during the transition period. Multiparous Holstein-Friesian cows in late gestation were randomly allocated to an untreated control group (n = 10) or a treatment group in which each cow received 500 g of zeolite A daily (n = 10) for 14 d prior to the expected calving date (actual duration = 17 ± 3 d prepartum). The cows grazed pasture, and each was supplemented with 2 kg/d of maize silage (dry matter basis), with or without zeolite, until calving. Blood samples for neutrophil isolation and analysis of plasma indicators of mineral status, energy status, liver function, and inflammation were collected pretreatment (covariate; d -19); on d -14 and -7 precalving; on the day of calving (d 0); and on d 1, 4, 7, and 28 postcalving. Neutrophils were isolated and gene expression was analyzed using microfluidic gene expression arrays. Neutrophil respiratory burst was assessed using stimulation with phorbol 12-myristate 13-acetate and flow cytometry. Plasma calcium and phosphorus revealed a treatment by time interaction; cows offered zeolite had greater plasma calcium concentrations at d 0, 1, and 4 postcalving and plasma phosphorus concentrations were lower in zeolite-treated cows during the precalving period until d 1 postcalving compared with control animals. Zeolite treatment downregulated neutrophil gene expression of CXCR4 and S100A8 and tended to lower gene expression for other immune mediators (CXCR1, IFNG, S100A12, and S100A9) compared with the control. Zeolite treatment did not affect neutrophil respiratory burst or expression of the other genes investigated. Plasma concentrations of cytokine IL-6 were reduced with zeolite treatment, which was most evident immediately postcalving (d 0, 1, and 7). Overall, feeding zeolite precalving had few effects on neutrophil gene expression and function; however, the lower gene expression of neutrophil inflammatory mediators may be due to altered availability of dietary minerals prepartum and indicates that zeolite A may control inflammation during the transition period.

Validity of assessing child feeding with virtual reality

Assessment of parents' child feeding behavior is challenging, and there is need for additional methodological approaches. Virtual reality technology allows for the creation of behavioral measures, and its implementation overcomes several limitations of existing methods. This report evaluates the validity and usability of the Virtual Reality (VR) Buffet among a sample of 52 parents of children aged 3-7. Participants served a meal of pasta and apple juice in both a virtual setting and real-world setting (counterbalanced and separated by a distractor task). They then created another meal for their child, this time choosing from the full set of food options in the VR Buffet. Finally, participants completed a food estimation task followed by a questionnaire, which assessed their perceptions of the VR Buffet. Results revealed that the amount of virtual pasta served by parents correlated significantly with the amount of real pasta they served, rs = 0.613, p < .0001, as did served amounts of virtual and real apple juice, rs = 0.822, p < .0001. Furthermore, parents' perception of the calorie content of chosen foods was significantly correlated with observed calorie content (rs = 0.438, p = .002), and parents agreed that they would feed the meal they created to their child (M = 4.43, SD = 0.82 on a 1-5 scale). The data presented here demonstrate that parent behavior in the VR Buffet is highly related to real-world behavior, and that the tool is well-rated by parents. Given the data presented and the potential benefits of the abundant behavioral data the VR Buffet can provide, we conclude that it is a valid and needed addition to the array of tools for assessing feeding behavior.

Dynamic Optical Gratings Accessed by Reversible Shape Memory

Shape memory polymers (SMPs) have been shown to accurately replicate photonic structures that produce tunable optical responses, but in practice, these responses are limited by the irreversibility of conventional shape memory processes. Here, we report the intensity modulation of a diffraction grating utilizing two-way reversible shape changes. Reversible shifting of the grating height was accomplished through partial melting and recrystallization of semicrystalline poly(octylene adipate). The concurrent variations of the grating shape and diffraction intensity were monitored via atomic force microscopy and first order diffraction measurements, respectively. A maximum reversibility of the diffraction intensity of 36% was repeatable over multiple cycles. To that end, the reversible shape memory process is shown to broaden the functionality of SMP-based optical devices.

Switchable micropatterned surface topographies mediated by reversible shape memory

Reversibly switching topography on micrometer length scales greatly expands the functionality of stimuli-responsive substrates. Here we report the first usage of reversible shape memory for the actuation of two-way transitions between microscopically patterned substrates, resulting in corresponding modulations of the wetting properties. Reversible switching of the surface topography is achieved through partial melting and recrystallization of a semi-crystalline polyester embossed with microscopic features. This behavior is monitored with atomic force microscopy (AFM) and contact angle measurements. We demonstrate that the magnitude of the contact angle variations depends on the embossment pattern.

Burkitt's lymphoma-associated c-Myc mutations converge on a dramatically altered target gene response and implicate Nol5a/Nop56 in oncogenesis

Burkitt’s Lymphomas (BLs) acquire consistent point mutations in a conserved domain of Myc, Myc Box I. We report that the enhanced transforming activity of BL-associated Myc mutants can be uncoupled from loss of phosphorylation and increased protein stability. Furthermore, two different BL-associated Myc mutations induced similar gene expression profiles independently of T58 phosphorylation, and these profiles are dramatically different from MycWT. Nol5a/Nop56, which is required for rRNA methylation, was identified as a gene hyperactivated by the BL-associated Myc mutants. We show that Nol5a is necessary for Myc-induced cell transformation, enhances MycWT-induced cell transformation, and increases the size of MycWT induced tumors. Thus, Nol5a expands the link between Myc-induced regulation of nucleolar target genes which are rate-limiting for cell transformation and tumor growth.

Evaluation of cinacalcet HCl treatment after kidney transplantation

BACKGROUND

Hyperparathyroidism often remains or develops after kidney transplantation. Vitamin D sterol used as treatment for an elevated parathyroid hormone (PTH) level and associated bone disease may be contraindicated due to hypercalcemia. The calcimimetic cinacalcet HCl (cinacalcet), which lowers PTH and calcium (Ca) in chronic kidney disease patients, may represent an alternate therapeutic modality.

METHODS

This multicenter, retrospective, observational study examined 41 kidney transplant patients receiving cinacalcet for ≥3 months starting ≥3 months posttransplantation. Levels of intact PTH, Ca, and phosphorus (P) were examined during the assessment phase (3-6 months after initiation).

RESULTS

Median PTH decreased 21.8% during the assessment phase (P < .001), with 32.5% of patients exhibiting a ≥30% decrease in PTH from baseline. Median Ca decreased 6.8% (P < .0001). Median serum P rose 10.0% (P = .0124), but remained within normal limits. The estimated glomerular filtration rate was stable throughout the study.

CONCLUSIONS

Cinacalcet may be useful for the treatment of hyperparathyroidism after kidney transplantation. Randomized, prospectively designed clinical trials are required to confirm these results.

Iatrogenic femoral artery pseudoaneurysms--a review of current methods of diagnosis and treatment

The common femoral artery is commonly used as arterial access for a wide range of radiological and cardiological procedures. Pseudoaneurysm formation is the most common arterial complication of femoral artery catheterization, and is diagnosed using colour Doppler ultrasound. Ultrasound-guided thrombin injection has replaced ultrasound-guided compression as the first-line treatment. The practicalities of thrombin injection (technique and types of thrombin available) and other treatment options are discussed. Awareness of pseudoaneurysm formation and the treatment options allows prompt diagnosis and successful treatment.

Survey for papillomatous digital dermatitis in Australian dairy cattle

OBJECTIVE

To determine whether Treponema-associated papillomatous digital dermatitis (PDD) occurs in Australian dairy cattle.

DESIGN

Mail-out questionnaire and histological and bacteriological examination of biopsy tissue from suspect PDD lesions.

PROCEDURE

The questionnaire was mailed to 375 veterinarians to evaluate their knowledge of PDD, determine if they had observed the disease in Australian dairy cattle, and to request biopsy material from suspicious cases. Biopsies were examined for histological and bacteriological evidence of PDD, including for the presence of spirochaetes.

RESULTS

Eighty-eight replies to the questionnaire were received (23.5%). Of 52 respondents who were aware of PDD as a possible cause of lameness, 26 reported observing the condition in Australian cattle. Of 32 respondents who were unaware of the condition, 6 reported observing lesions that might have been PDD. The majority of reports of PDD-like lesions came from the southern Australian states, the condition occurring during periods of high rainfall and proving responsive to topical or parenteral application of antimicrobials. Biopsies from five erosive lesions showed histological similarity to PDD whereas biopsies from five proliferative lesions were consistent with chronic inflammation, fibroma or cutaneous papilloma. The presence of spirochaetes was not demonstrated in any of the lesions by histological or bacteriological methods.

CONCLUSION

Anecdotal reports and analysis of biopsy material confirm that a condition similar to PDD does occur sporadically in dairy cattle in southern Australia. However, this condition has so far not been shown to be associated with the presence of spirochaetes in the lesions.

Nested deletions of the SRL pathogenicity island of Shigella flexneri 2a

In this study, we determined the boundaries of a 99-kb deletable element of Shigella flexneri 2a strain YSH6000. The element, designated the multiple-antibiotic resistance deletable element (MRDE), had recently been found to contain a 66-kb pathogenicity island (PAI)-like element (designated the SRL PAI) which carries the Shigella resistance locus (SRL), encoding resistance determinants to streptomycin, ampicillin, chloramphenicol, and tetracycline. The YSH6000 MRDE was found to be flanked by two identical IS91 elements present at the S. flexneri homologs of the Escherichia coli genes putA and mdoA on NotI fragment D. Sequence data from two YSH6000-derived MRDE deletants, YSH6000T and S2430, revealed that deletion of the MRDE occurred between the two flanking IS91 elements, resulting in a single IS91 element spanning the two original IS91 loci. Selection for the loss of tetracycline resistance confirmed that the MRDE deletion occurred reproducibly from the same chromosomal site and also showed that the SRL PAI and the SRL itself were capable of independent deletion from the chromosome, thus revealing a unique set of nested deletions. The excision frequency of the SRL PAI was estimated to be 10(-5) per cell in the wild type, and mutation of a P4-like integrase gene (int) at the left end of the SRL PAI revealed that int mediates precise deletion of the PAI.

Ferric dicitrate transport system (Fec) of Shigella flexneri 2a YSH6000 is encoded on a novel pathogenicity island carrying multiple antibiotic resistance genes

Iron uptake systems which are critical for bacterial survival and which may play important roles in bacterial virulence are often carried on mobile elements, such as plasmids and pathogenicity islands (PAIs). In the present study, we identified and characterized a ferric dicitrate uptake system (Fec) in Shigella flexneri serotype 2a that is encoded by a novel PAI termed the Shigella resistance locus (SRL) PAI. The fec genes are transcribed in S. flexneri, and complementation of a fec deletion in Escherichia coli demonstrated that they are functional. However, insertional inactivation of fecI, leading to a loss in fec gene expression, did not impair the growth of the parent strain of S. flexneri in iron-limited culture media, suggesting that S. flexneri carries additional iron uptake systems capable of compensating for the loss of Fec-mediated iron uptake. DNA sequence analysis showed that the fec genes are linked to a cluster of multiple antibiotic resistance determinants, designated the SRL, on the chromosome of S. flexneri 2a. Both the SRL and fec loci are carried on the 66,257-bp SRL PAI, which has integrated into the serX tRNA gene and which carries at least 22 prophage-related open reading frames, including one for a P4-like integrase. This is the first example of a PAI that carries genes encoding antibiotic resistance and the first report of a ferric dicitrate uptake system in Shigella.

A calcimimetic agent lowers plasma parathyroid hormone levels in patients with secondary hyperparathyroidism

BACKGROUND

The calcimimetic agent R-568 lowers plasma parathyroid hormone (PTH) levels in hemodialysis patients with mild secondary hyperparathyroidism, but its efficacy in those with more severe secondary hyperparathyroidism has not been studied.

METHODS

Twenty-one patients undergoing hemodialysis three times per week with plasma PTH levels between 300 and 1200 pg/mL were randomly assigned to 15 days of treatment with either 100 mg of R-568 (N = 16) or placebo (N = 5). Plasma PTH and blood ionized calcium levels were measured at intervals of up to 24 hours after oral doses on days 1, 2, 3, 5, 8, 11, 12, and 15.

RESULTS

Pretreatment PTH levels were 599 +/- 105 (mean +/- SE) and 600 +/- 90 pg/mL in subjects given R-568 or placebo, respectively, and values on the first day of treatment did not change in those given placebo. In contrast, PTH levels fell by 66 +/- 5%, 78 +/- 3%, and 70 +/- 3% at one, two, and four hours, respectively, after initial doses of R-568, remaining below pretreatment values for 24 hours. Blood ionized calcium levels also decreased after the first dose of R-568 but did not change in patients given placebo. Despite lower ionized calcium concentrations on both the second and third days of treatment, predose PTH levels were 422 +/- 70 and 443 +/- 105 pg/mL, respectively, in patients given R-568, and values fell each day by more than 50% two hours after drug administration. Predose PTH levels declined progressively over the first nine days of treatment with R-568 and remained below pretreatment levels for the duration of study. Serum total and blood ionized calcium concentrations decreased from pretreatment levels in patients given R-568, whereas values were unchanged in those given placebo. Blood ionized calcium levels fell below 1.0 mmol/L in 7 of 16 patients receiving R-568; five patients withdrew from study after developing symptoms of hypocalcemia, whereas three completed treatment after the dose of R-568 was reduced.

CONCLUSIONS

The calcimimetic R-568 rapidly and markedly lowers plasma PTH levels in patients with secondary hyperparathyroidism caused by end-stage renal disease.

Milk whey protein concentration and mRNA associated with beta-lactoglobulin phenotype

Two common genetic variants of β-lactoglobulin (β-lg), A and B, exist as co- dominant alleles in dairy cattle (Aschaffenburg, 1968). Numerous studies have shown that cows homozygous for β-lg A have more β-lg and less α-lactalbumin (α-la) and casein in their milk than cows expressing only the B variant of β-lg (Ng-Kwai-Hang et al. 1987; Graml et al. 1989; Hill, 1993; Hill et al. 1995, 1997). These differences have a significant impact on the processing characteristics of the milk. For instance, the moisture-adjusted yield of Cheddar cheese is up to 10% higher using milk from cows of the β-lg BB phenotype compared with milk from cows expressing only the A variant (Hill et al. 1997). All these studies, however, describe compositional differences associated with β-lg phenotype in established lactation only. No information is available on the first few weeks of lactation, when there are marked changes in the concentrations of β-lg and α-la (Pérez et al. 1990).

Mapping access to food in a deprived area: the development of price and availability indices

OBJECTIVE

To develop and map indices to illustrate variation in the cost and availability of healthy food.

DESIGN

Two contiguous wards in London were selected by virtue of their high Carstairs deprivation scores. A 2-km area was defined around a randomly chosen central point. All retail outlets selling food within the area were visited and their location recorded. A list of foods, acceptable to the local ethnically diverse population, which met current dietary guidelines, was devised. Data on the availability and price of 71 food items were collected. Indices were developed using SPSS and mapped using Geographic Information System (GIS) software.

RESULTS

Information on availability and prices were collected from 199 outlets. The mean price index shows how expensive a shop is relative to other shops in the area. The least cost index shows the relative expense of a shop using the cheapest ways of buying their range of foods. Shorthand indices were tested, using data on 19 of the 71 prices. Availability indices are also discussed, including a green availability index and a fresh green availability index. Illustrative maps of the shop locations and the mean price index and fresh green availability index are shown.

CONCLUSIONS

Data can be collected and indices developed which indicate geographic variation in shop 'expensiveness', and in the price and availability of healthy food. GIS software can be used to map these indices, to identify areas with high food prices or low availability.

A randomized phase 3 study of peripheral blood progenitor cell mobilization with stem cell factor and filgrastim in high-risk breast cancer patients

This randomized study compared the number of leukaphereses required to collect an optimal target yield of 5 x 10(6) CD34(+) peripheral blood progenitor cells/kg, using either stem cell factor (SCF) at 20 micrograms/kg/d in combination with Filgrastim at 10 micrograms/kg/d or Filgrastim alone at 10 micrograms/kg/d, from 203 patients with high-risk stage II, III, or IV breast cancer. Leukapheresis began on day 5 of cytokine administration and continued daily until the target yield of CD34(+) cells had been reached or a maximum of 5 leukaphereses performed. By day 5 of leukapheresis, 63% of the patients treated with SCF plus Filgrastim (n = 100) compared with 47% of those receiving Filgrastim alone (n = 103) reached the CD34(+) cell target yield. There was a clinically and statistically significant reduction (P <.05) in the number of leukaphereses required to reach the target yield for the patients receiving SCF plus Filgrastim (median, 4 leukaphereses) compared with patients receiving Filgrastim alone (median, 6 or more leukapherses; ie, <50% of patients reached the target in 5 leukaphereses). All patients receiving SCF were premedicated with antihistamines, albuterol, and pseudoephedrine. Treatment was safe, generally well tolerated, and not associated with life-threatening or fatal toxicity. In conclusion, SCF plus Filgrastim is a more effective peripheral blood progenitor cell (PBPC)-mobilization regimen than Filgrastim alone. In addition to the potential for reduced leukapheresis-related morbidity and costs, SCF offers additional options for obtaining cells for further graft manipulation.

Pressure sore prevention in hospital patients: a clinical audit

Pressure sores cause significant mortality and morbidity as well as being a financial burden on health-care services. Reduction of pressure sore incidence is a Department of Health priority. Pressure sores are accepted as largely preventable complications of illness and disability and the means to achieve prevention are available. The aim of this clinical audit was to identify potential contributing factors to pressure sore acquisition in an acute hospital setting. The results suggest that substantial changes in the approach to clinical management may be needed.

No evidence for basolateral secretion of milk protein in the mammary gland of lactating goats

Recent research suggests that a small percentage of milk proteins may be secreted basolaterally, which would have implications for our work on the permeability of tight junctions in the mammary epithelium. In our work, the presence of alpha-lactalbumin (LA) or lactose in plasma is used as an indicator of permeability. The aim of this study was to examine basolateral secretion by determining the presence of milk proteins in efferent mammary lymph. Five Saanen goats were fitted with mammary lymph catheters and were administered intramammary isosmotic bolus infusions of sucrose control solutions or ethylene glycolbis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to induce leaky tight junctions. Lymph samples were collected before and approximately 5 h after infusion. Lymph was analyzed by Western blotting for the presence of alpha-casein (CN), beta-CN, and alpha-LA No alpha-CN or beta-CN was detected in lymph, but alpha-LA was detected in all lymph samples. Moreover, the signal was much stronger in samples from goats that were treated with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, and concentrations of alpha-LA in lymph were significantly increased with this treatment. These changes and the absence of casein in lymph suggest increased permeability of tight junctions rather than basolateral secretion. In summary, these data do not support basolateral secretion.

Peripheral blood progenitor cell mobilization using stem cell factor in combination with filgrastim in breast cancer patients

The safety and optimal dose and schedule of stem cell factor (SCF) administered in combination with filgrastim for the mobilization of peripheral blood progenitor cells (PBPCs) was determined in 215 patients with high-risk breast cancer. Patients received either filgrastim alone (10 microg/kg/d for 7 days) or the combination of 10 microg/kg/d filgrastim and 5 to 30 microg/kg/d SCF for either 7, 10, or 13 days. SCF patients were premedicated with antiallergy prophylaxis. Leukapheresis was performed on the final 3 days of cytokine therapy and, after high-dose chemotherapy and infusion of PBPCs, patients received 10 microg/kg/d filgrastim until absolute neutrophil count recovery. The median number of CD34+ cells collected was greater for patients receiving the combination of filgrastim and SCF, at doses greater than 10 microg/kg/d, than for those receiving filgrastim alone (7.7 v 3.2 x 10(6)/kg, P < .05). There were significantly (P < .05) more CD34+ cells harvested for the 20 microg/kg/d SCF (median, 7.9 x 10(6)/kg) and 25 microg/kg/d SCF (median, 13.6 x 10(6)/kg) 7-day combination groups than for the filgrastim alone patients (median, 3.2 x 10(6)/kg). The duration of administration of SCF and filgrastim (7, 10, or 13 days) did not significantly affect CD34+ cell yield. Treatment groups mobilized with filgrastim alone or with the cytokine combination had similar hematopoietic engraftment and overall survival after PBPC infusion. In conclusion, the results of this study indicate that SCF therapy enhances CD34+ cell yield and is associated with manageable levels of toxicity when combined with filgrastim for PBPC mobilization. The combination of 20 microg/kg/d SCF and 10 microg/kg/d filgrastim with daily apheresis beginning on day 5 was selected as the optimal dose and schedule for the mobilization of PBPCs.

Occlusal indices revisited

With the increased interest in measuring the need for orthodontic treatment and the quality of the outcome of orthodontic care, the difficulties in using Grainger's Treatment Priority Index (TPI) to screen children in their tenth year is considered. The first part of the study investigated the level of validity of the TPI using 137 study models and three orthodontists. In the light of the results obtained, the TPI was modified. The clinical judgement of a further two orthodontists was compared with the scores obtained form the modified TPI, using another 121 study models. Three Community Dental Officers were employed initially to assess the training needs for personnel who were not trained in orthodontics. A further five Community Dental Officers were involved in the final training programmes. It was concluded that it will be very difficult to produce an index which considers all aspects of malocclusion and which can be used consistently by personnel untrained in orthodontics.

Amygdaloid influences on brain-stem neurones in the rabbit

1. Electrical stimulation of the central nucleus of the amygdala in the urethane or alpha-chloralose anaesthetized rabbit evokes a bradycardia with a rapid onset and a concomitant fall in arterial blood pressure. 2. Extracellular neuronal activity was recorded in the ipsilateral nucleus tractus solitarius and dorsal vagal nucleus whilst stimulating the ipsilateral central nucleus of the amygdala, the aortic and vagus nerves. 3. A total of 213 neurones were activated by stimulation of at least one of these inputs. 93 of these neurones received a marked excitatory input from the central nucleus with a wide range of latencies (2-100 ms). 50 of these cells also received inputs from either the aortic or vagus nerves, or both. 4. The activity of 42 vagal preganglionic neurones was recorded in the dorsal vagal nucleus of which 22 had properties typical of cardioinhibitory neurones. 9 of these vagal motoneurones received inputs from the central nucleus with latencies between 2 and 100 ms. Of these, 5 had physiological properties indicating they were cardio-inhibitory neurones. 5. We conclude that neurones in the nucleus tractus solitarius and dorsal vagal nucleus can be influenced by descending inputs arising from the central nucleus of the amygdala. Some of these neurones are also likely to be influenced by afferents innervating the thoracic viscera and arterial baroreceptors. The implications of these observations on the role of forebrain-brain-stem interactions in cardiovascular control are discussed.

The effects of a multicomponent smoking cessation program with chronic obstructive pulmonary disease outpatients

While a number of multicomponent treatments have been utilized to control smoking, many of these are not suitable for some populations such as chronic obstructive pulmonary disease (COPD) patients because they consist of aversion procedures which can stress the body's cardiovascular system. Little research has been published regarding nonaversive approaches to smoking control in a COPD patient population. This study examined the long-term effects of a nonaversive multicomponent smoking cessation program consisting of brand fading and stimulus control with a COPD outpatient population as measured by self-report. Using four COPD outpatients, this study employed a multiple baseline design across subjects for a visual analysis of treatment effects. At 3- and 6-month follow-up, one subject had quit smoking. Two subjects who continued to smoke reduced their smoking frequency and drastically reduced their nicotine intake by brand fading to a cigarette containing lower amounts of nicotine. A fourth subject returned to her original brand of cigarettes, although she reduced her smoking frequency. Collaborators and measurements of thiocyanate levels were used as reliability checks on subjects' self-report.

Comparison of dopamine and dobutamine therapy during intraaortic balloon pumping for the treatment of postcardiotomy low-output syndrome

Treatment of postcardiotomy low-output syndrome includes intraaortic balloon pumping (IABP), volume loading, pharmacological afterload reduction, and stimulation with an inotropic agent. This study compares the effectiveness of combined nitroprusside and dopamine therapy and nitroprusside and dobutamine therapy in 12 patients requiring IABP postoperatively. Serial hemodynamic measurements were made before and during infusion of nitroprusside and after administration of the combined therapy (N = 6 in each group). Prior to pharmacological therapy, cardiac index was 1.47 +/- 0.31 L/min/m2 and systemic vascular resistance (SVR) was 3,114 +/- 1,350 dynes sec cm-5 in patients subsequently given dopamine, and 1.59 +/- 0.38 L/min/m2 and 2,661 +/- 405 dynes sec cm-5, respectively, in those given dobutamine. With infusion of nitroprusside, both groups showed significant reduction in SVR. Nitroprusside plus either inotropic agent resulted in augmentation of cardiac index and an additional reduction in SVR, both changes being greater in the group given dopamine. Larger doses of dobutamine than dopamine were needed to achieve similar hemodynamic improvement. We conclude that the addition of an inotropic agent to vasodilator therapy during IABP results in a greater increase in cardiac index and a greater decrease in afterload than a vasodilator alone. In addition to its beneficial effect on renal perfusion at the dose required to effect these improvements, dopamine appears a better inotropic agent than dobutamine for postcardiotomy low-output syndrome.

The feasibility and validity of orthodontic screening of children in their tenth year

The study set out to investigate the problems of the implementation of the Court Report's suggestion that every child in its tenth year be screened for orthodontic treatment by "a dentist with special training in orthodontics' using Grainger's Treatment Priority Index (TPI). The study was divided into two parts. The standardization exercises used 31 orthodontic models of children in their tenth year. The problem of examiner variability, using a Community Dental Officer instead of an orthodontist and of bias that the TPI might have were examined. The main study involved the examination of 362 children in ten separate schools in Oxfordshire and investigated the problem of orthodontic screening at annual school inspections. The findings showed that the TPI may be able to provide a method for screening children in their tenth year if the weights of the clinical entities which are reducing the level of validity of the TPI are identified. The problem of scoring tooth displacements consistently would have to be taken into consideration when training personnel to use the TPI.

Development and evaluation of a long-term, implantable, electrically actuated left ventricular assist system: THI/Gould LVAS

A long-term, implantable, electrically actuated left ventricular assist system (THI/Gould LVAS) is being developed and characterized in vitro and in vivo for utilization in patients with end-stage heart disease. This system consists of five major components: a long-term, implantable blood pump (THI E-type ALVAD); an electrical-mechanical energy converter (Gould Model V); a control unit with batteries; a volume compensation system; and an external power supply and monitoring unit. Two of these components (blood pump and electrical-mechanical energy converter) have been integrated, and are undergoing chronic in vivo evaluations in calves. Thus far, 44 pneumatically and electrically actuated THI/Gould LVAS evaluations have been performed. This experience has resulted in greater than 6.5 years of actuation in vivo, with durations exceeding 1 year. System in vivo performance in terms of durability, mechanical reliability, hemodynamic effectiveness, and biocompatibility has been satisfactory. Demonstration of long-term (2-year) effectiveness in supporting the circulation is the ultimate goal.

Calcification in chronically-implanted blood pumps: experimental results and review of the literature

Blood compatibility is a major objective in the development of long-term, implantable circulatory assist (left ventricular assist devices) and replacement (total artificial heart) devices. An important problem in experimental studies in animals has been the propensity for calcification to occur at the blood/material interface. Presented is a summary of our experience (27 studies) with blood pump calcification and a review of the current literature regarding this complication.

Combined use of dopamine and nitroprusside therapy in conjunction with intra-aortic balloon pumping for the treatment of postcardiotomy low-output syndrome

Intra-aortic balloon pumping (IABP) has been utilized in our institution in over 600 patients for the treatment of postcardiotomy low-output syndrome, with a 59% survival rate. Volume loading and pharmacologic treatment have played integral roles in the overall treatment of this syndrome. This investigation documents the hemodynamic effectivenss of combined nitroprusside/dopamine therapy in patients who required IABP for weaning from cardiopulmonary bypass. Serial hemodynamic measurements were made before and during infusion of nitroprusside (0.5 to 5.0 microgram/kg/min) and after combined nitroprusside/dopamine (7.5 micrograms/kg/min) therapy in 10 patients during IABP. Prior to pharmacologic therapy, cardiac index was 1.6 +/- 0.4 L/min/m2 and systemic vascular resistance (SVR) was 2,774 +/- 932 dynes sec cm-5. After nitroprusside infusion, cardiac index increased to 1.8 +/- 0.5 L/min/m2 (NS) and SVR decreased to 1,957 +/- 791 dynes sec cm-5 (p less than 0.01). The simultaneous infusion of nitroprusside and dopamine resulted in further augmentation of cardiac index to 2.5 +/- 0.5 L/min/m2 (p less than 0.01) and an additional reduction of SVR to 1,439 +/- 358 dynes sec cm-5 (p less than 0.02). In addition, pressure-rate-product, an index of myocardial oxygen demand, was decreased by nitroprusside (p less than 0.02) but was not significantly altered by both agents. This study provides a rationale for the combined use of nitroprusside/dopamine in postcardiotomy low-output syndrome necessitating IABP when SVR is greater than 2,000 dynes sec cm-5 and cardiac index is less than 2.0 L/min/m2.

Development and evaluation of electrically actuated abdominal left ventricular assist systems for long-term use

A long-term, totally implantable, electrically actuated, abdominally positioned left ventricular assist system (ALVAS) is being developed, characterized in vitro, and evaluated in vivo for utilization in patients with end-stage cardiac failure refractory to conventional therapeutic techniques. The first two major subsystems of the ALVAS (the pusher-plate blood pump and electrical-mechanical energy converters) have been integrated and are undergoing in vitro characterization and long-term in vivo evaluations in calves. Duration of these studies has exceeded 6 months. System performance in terms of hemodynamic effectiveness, mechanical reliability, and biocompatibility has been excellent and no untoward effects have been observed. Long-term effectiveness of the ALVAS remains to be established in continuing experiments, with a 2 year period of clinical use as an ultimate goal.

Intraaortic balloon pumping women: effects of balloon size on survival

Between 1972 and 1978, 429 patients underwent intraaortic balloon pump (IABP) counterpulsation in our institution. Ninety-six were women (22.4). The overall mortality was 52.9% for men and 69.8% for women. During 1978, however, the mortality for women decreased to 57.1%, even though they comprised a larger percentage of patients (28.2%) than before. The major indication for IABP support in these women was ischemic myocardial dysfunction resulting in failure to wean from cardiopulmonary bypass (THI hemodynamic Classification C) despite volume expansion and pharmacologic support. Improved results were obtained with the use of larger intraaortic balloons and direct ascending aortic IABP insertion (which allowed use of larger, more effective 30 or 40 ml balloons), combined with delayed sternal closure.

Persistent atrial paralysis: Case report with light microscopy and ultrastructural analyses

Persistent atrial paralysis in a patient with complete heart block and mild mitral insufficiency is presented. Left atrial specimens obtained during implantation of a permanent cardiac pulse generator showed evidence of hypertrophy and fibrosis; subcellular degenerative changes ranged from near normal to irreversible, thus suggesting that atrial paralysis may be due to the replacement of normal atrial muscle with nonfunctional fibrous tissue.