Loss of control eating in children is associated with altered cortical and subcortical brain structure

Introduction

Loss of control (LOC) eating is the perceived inability to control how much is eaten, regardless of actual amount consumed. Childhood LOC-eating is a risk factor for the development of binge-eating disorder (BED), but its neurobiological basis is poorly understood. Studies in children with BED have shown both increased gray matter volume in regions related to top-down cognitive control (e.g., dorsolateral prefrontal cortex) and reward-related decision making (e.g., orbital frontal cortex) relative to healthy controls. However, no studies have examined brain structure in children with LOC-eating. To identify potential neurobiological precursors of BED, we conducted secondary analysis of five studies that conducted T1 MPRAGE scans.

Methods

A total of 143, 7-12-year-old children (M = 8.9 years, 70 boys) were included in the study, 26% of which (n = 37) reported LOC-eating (semi-structured interview). Age, sex, and obesity status did not differ by LOC-eating. Differences between children with and without LOC were examined for gray matter volume, cortical thickness, gyrification, sulci depth, and cortical complexity after adjusting for age, sex, total intercranial volume, weight status, and study.

Results

Children with LOC, relative to those without, had greater gray matter volume in right orbital frontal cortex but lower gray matter volume in right parahippocampal gyrus, left CA4/dentate gyrus, and left cerebellar lobule VI. While there were no differences in cortical thickness or gyrification, children with LOC-eating had great sulci depth in left anterior cingulate cortex and cuneus and greater cortical complexity in right insular cortex.

Discussion

Together, this indicates that children with LOC-eating have structural differences in regions related to cognitive control, reward-related decision-making, and regulation of eating behaviors.

Dietary Patterns and All-Cause Mortality: A NESR Systematic Review

Objectives

To inform the 2020–2025 Dietary Guidelines for Americans, the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) identified important public health questions to be examined by the 2020 Dietary Guidelines Advisory Committee. The Committee conducted a systematic review with support from USDA's Nutrition Evidence Systematic Review (NESR) team to answer the following question: What is the relationship between dietary patterns consumed and all-cause mortality?

Methods

The Committee developed protocols that described how they would use NESR's systematic review methodology to examine the evidence related to dietary patterns and all-cause mortality. NESR librarians conducted a literature search. NESR analysts dual-screened the results using pre-defined inclusion and exclusion criteria to identify articles published between 2000 and 2019 that evaluated dietary patterns and all-cause mortality. NESR analysts extracted data and assessed risk of bias of included studies. The Committee synthesized the evidence, developed conclusion statements, and graded the strength of the evidence underlying the conclusion statements.

Results

This review included one hundred and fifty-three studies, which were well-designed and conducted using rigorous methods, with low or moderate risks of bias. Precision, directness, and generalizability were demonstrated across the body of evidence. Results across studies were highly consistent in the foods and beverages included in the dietary patterns associated with reduced ACM risk. Robustness of results were confirmed by analyses with confounding factors.

Conclusions

Strong evidence demonstrates that dietary patterns in adults and older adults characterized by vegetables, fruits, legumes, nuts, whole grains, unsaturated vegetable oils, and fish, lean meat or poultry when meat was included, are associated with decreased risk of all-cause mortality. These patterns were also relatively low in red and processed meat, high-fat dairy, and refined carbohydrates or sweets. Some of these dietary patterns also included alcoholic beverages in moderation. (Grade: Strong)

Funding Sources

USDA, Food and Nutrition Service, Center for Nutrition Policy and Promotion, Alexandria, VA.

Dietary Patterns and Bone Health: A NESR Systematic Review

Objectives

To inform the 2020–2025 Dietary Guidelines for Americans, USDA and HHS identified important public health questions to be examined by the 2020 Dietary Guidelines Advisory Committee. The Committee conducted a systematic review with support from USDA's Nutrition Evidence Systematic Review (NESR) team to answer the question: What is the relationship between dietary patterns consumed and bone health?

Methods

The Committee developed protocols that described how they would use NESR's systematic review methodology to examine the evidence. NESR librarians conducted a literature search, and NESR analysts dual-screened the results using pre-defined inclusion and exclusion criteria to identify articles published between 2014 and 2019 that evaluated dietary patterns and bone health, which updates an existing review of evidence from 2000 to 2014. NESR analysts extracted data and assessed risk of bias of included studies. The Committee synthesized the evidence, developed conclusion statements, and graded the strength of the evidence underlying the conclusion statements.

Results

This systematic review update includes seven prospective cohort studies in adults and two in children, in addition to the thirteen studies included in the existing review. Most studies had few risks of bias, with good consistency, directness, precision and generalizability. Results from studies in adults were consistent in the foods and beverages in the dietary patterns associated with reduced fracture risk. Based on this new evidence in adults, the Committee updated the grade from limited to moderate. Evidence in children remains insufficient.

Conclusions

Moderate evidence indicates that a dietary pattern higher in fruits, vegetables, legumes, nuts, low-fat dairy, whole grains, and fish, and lower in meats (particularly processed meats), sugar sweetened beverages, and sweets is associated with favorable bone health outcomes in adults, primarily decreased risk of hip fracture. (Grade: Adults – Moderate) Insufficient evidence is available to determine the relationship between dietary patterns consumed during childhood and bone health. (Grade: Children – Grade not assignable)

Funding Sources

USDA, Food and Nutrition Service, Center for Nutrition Policy and Promotion, Alexandria, VA.

Using association rules mining to characterize loss of control eating in childhood

Childhood loss of control (LOC)-eating, the perceived inability to stop or control eating, is associated with increased risk for binge-eating disorder and obesity. However, the correlates of LOC-eating in childhood remain unclear. A secondary analysis of 177, 7-12-year-old children from five laboratory feeding studies was performed to investigate potential family (e.g., frequency of meals together, feeding practices), parental (e.g., education, weight status), and child (e.g., weight status, appetite traits) correlates of LOC-eating. Association rules mining (ARM¹), a data-driven approach, was used to examine all characteristics that were common across studies to identify which were associated with LOC-eating. Results showed LOC-eating was characterized by a combination of child appetitive behaviors and parental feeding practices. In particular, LOC-eating was associated with low parental pressure to eat in combination with a high propensity to want to eat all the time and frequent refusal or dislike of novel foods. This pattern of both food approach (i.e., wanting to eat all the time) and avoidant behaviors (i.e., food fussiness) highlights the need for more research to characterize the complex patterns of appetitive traits associated with LOC-eating. In contrast, the absence of LOC-eating was associated with a low propensity to want to eat all the time, greater family income, and infrequent emotional overeating. Therefore, propensity to want to eat all the time, a single question from the Children's Eating Behavior Questionnaire, characterized both the presence and absence of LOC-eating, highlighting the need for more research to determine if this question captures clinically relevant individual differences. Future studies addressing these questions will advance our understanding of pediatric LOC-eating and may lead to interventions to reduce risk for more severe eating disorder symptomology.

Expression of Apoptosis-regulating Proteins Bcl-2 and Bax in Lymph Node Aspirates from Dogs with Lymphoma

Background

Dysregulated apoptosis is a hallmark of tumorigenesis, and is also involved in resistance to cytotoxic treatment, and might be relevant in lymphoma in dogs.

Hypothesis/Objectives

That Bcl‐2/Bax expression patterns differ between lymphoma immunophenotypes, and that Bcl‐2/Bax ratio is correlated with prognosis.

Animals

Fifty‐five client‐owned dogs with multicentric lymphoma and 5 healthy dogs.

Methods

Prospective, case–control study. We compared 3 methods (flow cytometry, qRT‐PCR, Western blot) for Bcl‐2 and Bax quantification in a subset of dogs. The effect of time on Bcl‐2/Bax ratios measured by flow cytometry was assessed in lymphoma cell lines. Immunophenotype and Bcl‐2/Bax expression by flow cytometry were determined in LN aspirates from all dogs with multicentric lymphoma compared to healthy dogs. Progression‐free survival (PFS) was retrospectively evaluated in a group of dogs all receiving similar treatment.

Results

Bcl‐2/Bax ratios remain consistent for at least 5 days after sample collection. Bcl‐2/Bax ratio was higher in dogs with T‐cell lymphoma (TCL; median 0.97, range 0.37–1.36) compared to B‐cell lymphoma (BCL; median 0.36, range 0.07–1.45) (P < .0001) and normal dogs (median 0.36, range 0.21–0.48) (P = .0006), respectively. Dogs with Bcl‐2/Bax ratios higher than the median of the group experienced a median PFS of 101 days and dogs with ratios equal and lower than the median had PFS of 130 days (P = .19).

Conclusions and clinical importance

Higher intrinsic resistance to apoptosis following cytotoxic treatment might contribute to the less favorable prognosis associated with multicentric TCL in dogs. Whether Bcl‐2/Bax will be helpful to identify canine BCL and TCL with more aggressive and more indolent behavior, respectively, should be evaluated in larger prospective clinical studies.

Mechanisms of the portion size effect. What is known and where do we go from here?

Childhood obesity is a persistent problem worldwide, and of particular concern in the United States. Clarifying the role of the food environment in promoting overeating is an important step toward reducing the prevalence of obesity. One potential contributor to the obesity epidemic is the increased portion sizes of foods commonly served. Portion sizes of foods served both at home and away from home have dramatically increased over the past 40 years. Consistently, short-term studies have demonstrated that increasing portion size leads to increased food intake in adults and children, a phenomenon known as the portion size effect. However, the mechanisms underlying this effect are poorly understood. Understanding these mechanisms could assist in clarifying the relationship between portion size and weight status and help inform the development of effective obesity interventions. First, we review the role of visual cues, such as plate size, unit, and utensil size as a potential moderator of the portion size effect. In addition, we discuss meal microstructure components including bite size, rate, and frequency, as these may be altered in response to different portion sizes. We also review theories that implicate post-ingestive, flavor-nutrient learning as a key moderator of the portion size effect. Furthermore, we present preliminary data from an ongoing study that is applying neuroimaging to better understand these mechanisms and identify modifiable child characteristics that could be targeted in obesity interventions. Our tentative findings suggest that individual differences in cognitive (e.g. loss of control eating) and neural responses to food cues may be critical in understanding the mechanisms of the portion size effect. To advance this research area, studies that integrate measures of individual subject-level differences with assessment of food-related characteristics are needed.

P02 - 362 - Schizencephaly and psychosis

Schizencephaly is an uncommon congenital disorder of cerebral cortical development, defined as a gray matter-lined cleft extending from the pial surface to the ventricle. It is a neuronal migration anomaly, caused by insults to migrating neuroblasts during 3rd to 5th gestational months.

Ischemia, germline mutations, intrauterine infections and exposure to drugs have been implicated in its etiology. The outcome relates with the severity of pathology. Unilateral closed lip schizencephaly has the mildest clinical picture and bilateral open lip the most severe. The most prominent manifestations are motor deficits and seizures.

Schizencephaly has been related with psychosis. However, there is paucity of literature exploring this relation. Pubmed search with “Schizencephaly AND Psychotic disorders OR Bipolar Disorders” as Mesh terms resulted in 9 results. Of these four discussed Schizencephaly. Rest five reports were related to other disorders of cortical malformation. We present an interesting case of schizencephaly associated with psychosis and congenital hemiparesis. We also present a review of literature available for this rare association.

This case points towards the role of neurodevelopmental abnormalities in the manifestation of psychosis and bipolar affective disorder. It indicates that presence of neurodevelopmental anomalies may have pathoplastic effects on the presentation of psychosis and may also influence treatment response adversely. A possible mechanism explaining the development of psychosis in schizencephaly is the disruption in intracortical connections. There is also a possibility of underlying ictal phenomenon leading to psychosis. The above case provides support to the neurodevelopmental theory of Schizophrenia.

Genotyping of Campylobacter coli isolated from humans and retail meats using multilocus sequence typing and pulsed-field gel electrophoresis

AIMS

To determine the antimicrobial resistant profiles and clonality of Campylobacter coli isolated from clinically ill humans and retail meats.

METHODS AND RESULTS

A total of 98 C. coli isolates (20 from humans and 78 from retail meats) were phenotypically characterized. Antimicrobial susceptibility testing was done using agar dilution method for ciprofloxacin, gentamicin, erythromycin and doxycycline. Seventy C. coli isolates including humans (n = 20) and retail meats (n = 50) were genotyped by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Resistance to ciprofloxacin was found in 29% and 15% of isolates from retail meats and humans. We observed 61 PFGE profiles using two enzymes (SmaI, KpnI) with an Index of discrimination of 0.99, whereas MLST generated 37 sequence types. Two clonal complexes were identified with 58 (82%) C. coli isolates clustered in the ST-828 complex.

CONCLUSIONS

Resistance to ciprofloxacin and erythromycin was identified in C. coli obtained from retail meats and ill humans. PFGE typing of C. coli isolates was more discriminatory than MLST. Grouping of C. coli isolates (82%) by MLST in ST-828 clonal complex indicates a common ancestry.

SIGNIFICANCE AND IMPACT OF THE STUDY

A high frequency of resistance found to ciprofloxacin and erythromycin is concerning from food safety perspective. PFGE using single or double restriction enzymes was found to be more discriminatory than MLST for genotyping C. coli. Overall, the C. coli populations recovered from humans and retail meats were genotypically diverse.

Characterization of Salmonella Typhimurium of Animal Origin Obtained from the National Antimicrobial Resistance Monitoring System

Salmonella Typhimurium remains one of the most common causes of salmonellosis in animals and humans in the United States. The emergence of multi-drug resistant Salmonella reduces the therapeutic options in cases of invasive infections, and has been shown to be associated with an increased burden of illness. In this study, 588 S. Typhimurium (including var. Copenhagen) isolates obtained from either animal diagnostic specimens (n = 199) or food animals after slaughter/processing (n = 389) were examined for antimicrobial susceptibility, presence of class-1 integrons, and characterized using pulsed-field gel electrophoresis and phage typing. Seventy-six percent (448/588) of isolates were resistant to at least one antimicrobial. Salmonella isolates displayed resistance most often to streptomycin (63%), tetracycline (61%), ampicillin (61%), and to a lesser extent, chloramphenicol (36%), ceftiofur (15%), gentamicin (9%), and nalidixic acid (4%), with more resistance observed among diagnostic isolates. Salmonella recovered from turkeys (n = 38) exhibited the highest rates of resistance, with 92% of isolates resistant to least one antimicrobial, and 58% resistant to > or =10 antimicrobials. Class 1 integrons were present in 51% of all isolates. Five integron associated resistance genes (aadA, aadB, pse-1, oxa-2 and dhfr) were identified. A total of 311 PFGE patterns were generated using XbaI, indicating a genetically diverse population. The largest PFGE cluster contained 146 isolates, including DT104 isolates obtained from all seven animal species. Results demonstrated a varied spectrum of antimicrobial resistance, including several multidrug resistant clonal groups, among S. Typhimurium and S. Typhimurium var. Copenhagen isolates recovered from both diagnostic and slaughter/processing samples.

Antimicrobial susceptibility and genetic relatedness of Salmonella serovars isolated from animal-derived dog treats in the USA

OBJECTIVES

The objectives of this study were to determine the potential risk of dog treats in transmitting Salmonella to humans in the USA, and to characterize genetic relatedness and antimicrobial resistance among the isolates.

METHODS

A total of 158 dog treats derived from pig ears and other animal parts were randomly collected nationwide and assayed for the presence of Salmonella. The Salmonella isolates were characterized using serotyping, pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing.

RESULTS

Forty-one percent (65/158) of samples were positive for Salmonella. Eighty-four Salmonella isolates, comprising 24 serotypes, were recovered from the 65 positive samples. Fourteen samples were contaminated with more than one Salmonella serotype. PFGE analysis of 78 Salmonella isolates yielded 64 patterns. S. Infantis with PFGE patterns indistinguishable from those of strains identified in Canadian outbreaks in 1999 were recovered in several dog treat products. The majority of Salmonella isolates were susceptible to the antimicrobials tested; however, resistance was observed to tetracycline (26%), streptomycin (23%), sulfamethoxazole (19%), chloramphenicol (8%) and ampicillin (8%). Twenty-eight (36%) Salmonella isolates were resistant to at least one antimicrobial and 10 (13%) isolates displayed resistance to four or more antimicrobials. Two isolates were identified as S. Typhimurium DT104 with the characteristic penta-resistance phenotype (ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline). One S. Brandenburg isolate was resistant to eight antimicrobials. Seven Salmonella isolates also contained class I integrons encoding resistance genes to aminoglycosides, beta-lactam and streptothricin antimicrobials.

CONCLUSIONS

The study indicates that animal-derived dog treats in the USA could be a potential source of animal and human infections with Salmonella, including multidrug-resistant Salmonella strains.

Identification and expression of cephamycinase bla(CMY) genes in Escherichia coli and Salmonella isolates from food animals and ground meat

Twenty-one Salmonella and 54 Escherichia coli isolates, recovered from food animals and retail ground meats, that exhibited decreased susceptibilities to ceftiofur and ceftriaxone were shown to possess a bla(CMY) gene. The bla(CMY-4) gene was identified in an E. coli isolate recovered from retail chicken and was further shown to be responsible for resistance to cephalothin, ampicillin, and amoxicillin-clavulanic acid and elevated MICs of ceftriaxone, cefoxitin, and ceftiofur.

Structure of the insecticidal bacterial delta-endotoxin Cry3Bb1 of Bacillus thuringiensis

The coleopteran-active delta-endotoxin Cry3Bb1 from Bacillus thuringiensis (Bt) strain EG7231 is uniquely toxic to Diabrotica undecimpunctata, the Southern corn rootworm, while retaining activity against Leptinotarsa decemlineata, the Colorado potato beetle. The crystal structure of the delta-endotoxin Cry3Bb1 has been refined using data collected to 2.4 A resolution, with a residual R factor of 17.5% and an R(free) of 25.3%. The structure is made up of three domains: I, a seven-helix bundle (residues 64-294); II, a three-sheet domain (residues 295-502); and III, a beta-sandwich domain (residues 503-652). The monomers in the orthorhombic C222(1) crystal lattice form a dimeric quaternary structure across a crystallographic twofold axis, with a channel formed involving interactions between domains I and III. There are 23 hydrogen bonds between the two monomers conferring structural stability on the dimer. It has been demonstrated that Cry3Bb1 and the similar toxin Cry3A form oligomers in solution. The structural results presented here indicate that the interactions between domains I and III could be responsible for the initial higher order structure and have implications for the biological activity of these toxins. There are seven additional single amino-acid residues in the sequence of Cry3Bb1 compared with that of Cry3A; one in domain I, two in domain II and four in domain III, which also shows the largest conformational difference between the two proteins. These changes can be implicated in the selectivity differences noted for these two delta-endotoxins.

Identification and characterization of integron-mediated antibiotic resistance among Shiga toxin-producing Escherichia coli isolates

A total of 50 isolates of Shiga toxin-producing Escherichia coli (STEC), including 29 O157:H7 and 21 non-O157 STEC strains, were analyzed for antimicrobial susceptibilities and the presence of class 1 integrons. Seventy-eight (n = 39) percent of the isolates exhibited resistance to two or more antimicrobial classes. Multiple resistance to streptomycin, sulfamethoxazole, and tetracycline was most often observed. Class 1 integrons were identified among nine STEC isolates, including serotypes O157:H7, O111:H11, O111:H8, O111:NM, O103:H2, O45:H2, O26:H11, and O5:NM. The majority of the amplified integron fragments were 1 kb in size with the exception of one E. coli O111:H8 isolate which possessed a 2-kb amplicon. DNA sequence analysis revealed that the integrons identified within the O111:H11, O111:NM, O45:H2, and O26:H11 isolates contained the aadA gene encoding resistance to streptomycin and spectinomycin. Integrons identified among the O157:H7 and O103:H2 isolates also possessed a similar aadA gene. However, DNA sequencing revealed only 86 and 88% homology, respectively. The 2-kb integron of the E. coli O111:H8 isolate contained three genes, dfrXII, aadA2, and a gene of unknown function, orfF, which were 86, 100, and 100% homologous, respectively, to previously reported gene cassettes identified in integrons found in Citrobacter freundii and Klebsiella pneumoniae. Furthermore, integrons identified among the O157:H7 and O111:NM strains were transferable via conjugation to another strain of E. coli O157:H7 and to several strains of Hafnia alvei. To our knowledge, this is the first report of integrons and antibiotic resistance gene cassettes in STEC, in particular E. coli O157:H7.

A community-based study of the epidemiology of Helicobacter pylori infection and associated asymptomatic gastroduodenal pathology

OBJECTIVES

To document the epidemiology of Helicobacter pylori infection in a normal population, to assess asymptomatic H. pylori positive individuals for the presence of gastroduodenal disease, and to compare the macroscopic and microscopic findings at endoscopy in this group with those of patients presenting with dyspepsia.

DESIGN/METHODS

Serum was collected from blood donors and assessed for the presence of anti-H. pylori IgG antibodies. A randomly selected group of asymptomatic blood donors and dyspeptic patients underwent endoscopy.

RESULTS

The seroprevalence of H. pylori in 1000 subjects was 43.0%. The prevalence of infection increased from 29% in 18-30 year olds to 62% in 46-60 year olds (P < 0.01). The infection was more prevalent in individuals from social classes IV and V (50.0%) than social classes I and II (36.9%) (P < 0.01). There was no difference between the H. pylori positive asymptomatic individuals (n = 37) and matched dyspeptic patients (n = 29) at endoscopy with regard to duodenal ulcer (13.5% vs. 17.2%) or gastroduodenal erosions (24.3% vs. 20.7%) while 5.4% of the former had gastro-oesophageal reflux compared to 27.6% of the latter. Overall, 56.8% of the H. pylori positive asymptomatic group had a normal macroscopic endoscopy compared with 31% of the dyspeptic group. Histology of the gastric mucosa did not reveal any significant differences between the two groups. In H.pylori negative asymptomatic individuals (n = 13) 92.3% had a normal endoscopy (7.7% had grade I gastro-oesophageal reflux) compared with 61.5% of a matched dyspeptic group (n = 13).

CONCLUSION

H.pylori infection, symptomatic and asymptomatic, is associated with significant pathology, and screening for the infection may be indicated for the prevention of gastroduodenal diseases.

Enhanced cultivation of Helicobacter pylori in liquid media

AIMS

To evaluate a technique for culture of Helicobacter pylori in large quantities of liquid media and to determine the factors that could influence the results.

METHODS

Fifteen clinical isolates of H pylori and a reference strain of H pylori NCTC11637 were used to evaluate a method to cultivate the organism in 100 ml liquid medium comprising brain heart infusion broth with 5% horse serum and 0.25% yeast extract. Tissue culture flasks containing the inoculated liquid medium were placed in a CO2 incubator with 5% CO2 for 2 hours and then incubated in a shaking incubator at 120 rpm.

RESULTS

All the clinical isolates and the reference strain grew in the broth, although only a moderate growth of the reference strain occurred. Inoculum size significantly influenced the kinetics of growth of H pylori in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B, used to suppress contamination, did not affect growth of H pylori in the medium. CO2 was essential for H pylori to grow or survive in the liquid medium. Incubation with CO2 in a CO2 incubator for 30 minutes or 2 hours did not affect the results.

CONCLUSIONS

H pylori can be cultivated in large quantities of brain heart infusion broth with 5% horse serum and 0.25% yeast extract. Initial inoculum concentrations influence the kinetics of H pylori growth in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B can be used as selective antimicrobial agents. CO2 is essential for initial growth of H pylori in liquid media. The findings in this study may provide a useful, reproducible, and simple method for biochemical, molecular, and physiological studies of H pylori, when those require large quantities of the organism.

Purification and crystallization of insecticidal delta-endotoxin CryIIIB2 from Bacillus thuringiensis

CryIIIB2, an insecticidal protein from Bacillus thuringiensis has been crystallized from 0.6 M NaBr and HEPES buffer at pH 7.0 and X-ray diffraction data collected on a native crystal to 2.4 A. The insecticidal protein was obtained from a Bacillus thuringiensis (Bt) strain EG7231. Crystals of the endotoxin are orthorhombic, space group C2221, with unit cell dimensions of a = 122.44, b = 131.81, and c = 105.37 A. A unit cell contains one molecule of the 67,000 Da endotoxin per asymmetric unit.

Delta-endotoxins form cation-selective channels in planar lipid bilayers

Delta-endotoxins CryIA(c) and CryIIIA, two members of a large family of toxic proteins from Bacillus thuringiensis, were each allowed to interact with planar lipid bilayers and were analyzed for their ability to form ion-conducting channels. Both of these toxins made clearly resolved channels in the membranes and exhibited several conductance states, which ranged from 200 pS to about 4000 pS (in 300 mM KCl). The channels formed by both toxins were highly cation-selective, but not ideally so. The permeability ratio of K+ to Cl- was about 25 for both channels. The ability of these proteins to form such channels may account for their toxic action on sensitive cells, and suggests that this family of toxins may act by a common mechanism.

Hemodynamic effects of moricizine at rest and during supine bicycle exercise: results in patients with ventricular tachycardia and left ventricular dysfunction

To evaluate the hemodynamic effects of moricizine, 20 patients with frequent nonsustained ventricular tachycardia (VT) with a mean left ventricular ejection fraction (EF) of 39 +/- 14% were enrolled in a prospective single-blind, placebo-controlled study. Hemodynamic measurements were performed at rest and during supine bicycle exercise on placebo and moricizine therapy (10 mg/kg/day). Although 16 of 19 patients experienced no rest or exercise deterioration in hemodynamic parameters during drug dosing, three patients had acute deterioration of pulmonary capillary wedge pressure and cardiac index (CI) on moricizine. During follow-up of 6 +/- 3 months, two subgroups were identified: 10 of 19 patients had effective long-term reduction in VT, whereas 9 of 19 patients had poor control of ventricular arrhythmia or congestive heart failure and were discontinued from the trial. Baseline EF and hemodynamic parameters at rest were similar in both patient subgroups. However, protocol dropouts had a hemodynamic response to exercise on moricizine that was significantly depressed as compared to patients with a favorable antiarrhythmic outcome (p less than 0.02). The following hemodynamic profile characterizes patients unlikely to have an antiarrhythmic response to moricizine: an increase in CI of less than 1.0 L/min/m2 and no increase in left ventricular stroke work index during supine exercise.

Efficacy and safety of moricizine in patients with ventricular tachycardia: results of a placebo-controlled prospective long-term clinical trial

This was a prospective, placebo-controlled, single-blind trial of moricizine (ethmozine) in a dose averaging 10 mg/kg/day in 50 patients, the single entrance criterion being the presence of 10 or more runs of nonsustained ventricular tachycardia (VT) on a screening 24 hr ambulatory electrocardiographic (ECG) recording. Electrophysiologic study was not included as part of this trial design. The placebo frequency of VT (average 3 days of recording) was 1036 +/- 479 runs of VT per day. Most patients (31/50) had coronary artery disease. The study population had a mean left ventricular ejection fraction (LVEF) of 36 +/- 16%; 20 patients also had a history of sustained VT. Protocol failure was defined as failure to achieve a 75% or greater reduction in runs of VT (as judged by ambulatory ECG recording) and/or recurrence of sustained VT while on moricizine. Among the 48 patients treated with moricizine, the drug was initially efficacious in 35 (73%), with two-thirds having total abolition of nonsustained VT. Although it was effective in reducing runs of nonsustained VT, moricizine was ineffective in preventing the recurrence of sustained VT (63% failure rate). Side effects were uncommon and the drug was well tolerated in most patients with LVEFs of 30% or less.

Comparative effect of disopyramide and ethmozine in suppressing complex ventricular arrhythmias by use of a double-blind, placebo-controlled, longitudinal crossover design

This placebo-controlled, double-blind, longitudinal crossover study compares the efficacy of disopyramide and ethmozine, a new investigational drug, in suppressing frequent (40 or more per hour) ventricular premature depolarizations (VPDs) in 27 patients completing a 37 day protocol. Although both drugs significantly reduced VPDs relative to placebo, ethmozine was a superior antiarrhythmic drug in ach9eving near-total abolition of VPDs (30% of patients), which was never observed during disopyramide dosing (p less than .05). At the 80% VPD reduction level, ethmozine was effective in 56% of all patients compared with an effectiveness in only 22% of patients during disopyramide therapy (p less than .05). The mean peak plasma level of ethmozine was 0.66 +/- 0.8 micrograms/ml, which significantly fell to a trough level of 0.1 +/- 0.08 micrograms/ml (p less than .001). Mean peak and trough plasma levels of disopyramide exhibited less fluctuation (2.6 +/- 0.9 micrograms/ml vs 2.2 +/- 0.9 micrograms/ml). Ethmozine had no effect on the QT interval, whereas disopyramide prolonged it significantly. Importantly, while disopyramide produced serious side effects in 30% of patients, ethmozine was well tolerated with no statistically significant side effects compared with placebo.

Phosphorylation of the (Na,K)-ATPase by a plasma membrane-bound protein kinase in friend erythroleukemia cells

A decrease in the activity of the (Na,K)-ATPase is an early and essential step in commitment of Friend virus-infected murine erythroleukemia cells to terminal erythroid differentiation. Plasma membranes from these cells were purified and shown to contain ouabain-inhibitable (Na,K)-ATPase present as approximately 0.4% of the total membrane protein. Protein kinase activity also co-purified with the plasma membrane and preferentially phosphorylated a Nonidet P-40 detergent-extractable 100,000-Da peptide. The 100,000-Da phosphopeptide migrated with the alpha subunit of dog kidney (Na,K)-ATPase when electrophoresis was carried out in the presence of sodium dodecyl sulfate in either 5 or 10% polyacrylamide gels. In two-dimensional gel electrophoresis, it separated into a series of spots between pH 5.1 and 5.4, while dog kidney alpha subunit appeared as a doublet at pH 5.3-5.4. When Nonidet P-40-solubilized plasma membranes were passed through a ouabain affinity column in the presence of Mg2+, Na+, and ATP, the 100,000-Da phosphopeptide was retained and could be eluted by ouabain. This peptide was also phosphorylated in living murine erythroleukemia cells, and proteolysis patterns of the peptide labeled in vitro, the peptide labeled in vivo, and the purified dog kidney alpha subunit using V8 protease were nearly identical. Phosphothreonine was detected in both the peptides labeled in vivo and in vitro.

An investigation into the interaction between ethanol at low doses and the benzodiazepines nitrazepam and temazepam on psychomotor performance in normal subjects

Ten healthy male volunteers received, in randomized order, temazepam 20 mg, nitrazepam 5 mg or placebo in combination with ethanol 0.1, 0.2 or 0.4 g/kg. Psychomotor tests were performed at regular intervals over 8 h. Ethanol alone at 0.4 g/kg significantly showed simple reaction time for between 30 and 60 min, whereas nitrazepam (5 mg) or temazepam (20 mg) plus the placebo alcohol dose (0.1 g/g) had no significant effect. The benzodiazepines and ethanol (0.2 and 0.4 g/kg) in combination showed no potentiation or prolongation of action. Both ethanol and the two benzodiazepines significantly reduced critical flicker detection in themselves and, in combination, had additive effects. Only nitrazepam and temazepam produced decreases in performance in the code substitution (DSST) test, and the time course of action of nitrazepam was markedly longer than that of temazepam. Ethanol alone had no detectable effect on immediate recall, prompted recall, learning, or word recognition tests. Both benzodiazepines reduced immediate and prompted recall and nitrazepam, in addition, reduced word recognition ability. It is concluded that the spectrum of CNS depressant actions of ethanol and the benzodiazepines are different and that there is no evidence of a potentiation or prolongation of their effects by concomitant administration of the doses used in the present study.

New Method for Differentiating Members of the Bacillus cereus Group: Collaborative Study

A collaborative study was conducted of a new method for differentiating members of the Bacillus cereus group. Using the new method, each of 14 collaborators identified 8 Bacillus cultures, which represented 3 biotypes of the B. cereus group. Each culture was tested for motility, hemolytic activity on trypticase- soy-sheep blood agar, and rhizoid growth on nutrient agar; carbol-fuchsin stain was used to determine the presence of protein toxin crystals. Cultures were identified as B. cereus (biotype 1), B. cereus var. mycoides (biotype 2), or B. thuringiensis (biotype 3). All collaborators correctly identified the unknown cultures and classified them correctly as to biotype. There were no statistically significant differences in the identification rates among the different laboratories. Additional tests by one participant on 5 strains of Bacillus anthracis showed that the new method is also adequate for differentiating B. anthracis from typically reacting strains of B. cereus. The method has been adopted interim official first action.

Comparative Efficiency of Brilliant Green, Bismuth Sulfite, Salmonella-Shigella, Hektoen Enteric, and Xylose Lysine Desoxycholate Agars for the Recovery of Salmonella from Foods: Collaborative Study

The relative efficiency of brilliant green (BG), bismuth sulfite (BS), Salmonella-Shigella (SS), xylose lysine desoxycholate (XLD), and Hektoen enteric (HE) agars for the recovery of Salmonella from 5 foods was collaboratively studied in 11 laboratories. The analytical efficiency of various paired combinations of the 5 agars was statistically compared according to 3 parameters: (1) productivity or recovery of Salmonella, (2) rate of enumeration of cultures that were false positive for Salmonella, and (3) rate of enumeration of false-negative reactions. In descending order of productivity, the sequential rankingwasBS, XLD, HE, BG, and SS agars. In ascending order, the rates of false-positive reactions based on a statistical analysis of paired agar combinations was HE, BS, BG and XLD (tie), and SS agars. Analogously, in ascending order, the sequence of false-negative reaction rates was BS, XLD, HE, BG, and SS agars. The combination of BS, XLD, and HE agars is more efficient for recovery of Salmonella from foods than is the present official combination of BG, BS, and SS agars. The revision of official final action method 46.054 to replace the combination of BG, BS, and SS agars with a combination of BS, XLD, and HE agars has been adopted official first action.