The Role of Fresh Beef Intake and Mediterranean Diet Adherence during Pregnancy in Maternal and Infant Health Outcomes

Beef is an excellent source of nutrients important for maternal health and fetal development. It is also true that the Mediterranean diet is beneficial for the health of both the mother and offspring; however, the relative value of fresh beef intake within Mediterranean diet patterns during pregnancy is unknown. The objective of this project was two-fold: (1) assess the relationship between beef intake and nutrient intake in a pregnant population; (2) assess the relationship between maternal beef consumption among varying degrees of Mediterranean diet adherence with maternal risk of anemia and infant health outcomes. This is a secondary analysis of an existing cohort of pregnant women (n = 1076) who participated in one of two completed clinical trials examining the effect of a docosahexaenoic acid supplementation on birth and offspring outcomes. Women were enrolled between 12 and 20 weeks of gestation and were followed throughout their pregnancies to collect maternal and infant characteristics, food frequency questionnaires [providing beef intake and Mediterranean diet (MedD) adherence], and supplement intake. Women with the highest fresh beef intake had the highest intake of many micronutrients that are commonly deficient among pregnant women. Fresh beef intake alone was not related to any maternal or infant outcomes. There was a reduced risk of anemia among women with medium to high MedD quality and higher fresh beef intake. Women in the medium MedD group had 31% lower odds of anemia, and women in the high MedD group had 38% lower odds of anemia with every one-ounce increase in fresh beef intake, suggesting that diet quality indices may be misrepresenting the role of fresh beef within a healthy diet. These findings show that beef intake increases micronutrient intake and may be protective against maternal anemia when consumed within a healthy Mediterranean diet pattern.

Association of diabetes mellitus with dementia- and non-dementia-related mortality amongst women: a secondary competing risks analysis of the California Teachers Study

BACKGROUND AND PURPOSE

The prevalence of dementia is rapidly increasing. Attempts to further understand modifiable risk factors such as diabetes mellitus (DM) are urgently needed to inform public health policies for prevention. Thus, the objective of the current study was to assess the relationship between DM and risk of dementia and non-dementia mortality amongst women in the California Teachers Study prospective cohort.

METHODS

Women (n = 124,509) aged 22-104 years at baseline were included. DM was ascertained from self-reported questionnaires and hospital-linked records. Dementia-related deaths were ascertained from state and national records. Competing risk regression models were used to estimate cause-specific hazard ratios and 95% confidence intervals for the association of DM with dementia- and non-dementia-related mortality.

RESULTS

There were 10,511 total DM cases and 3625 deaths due to dementia over a mean of 21.3 years of follow-up. Fully adjusted cause-specific hazard ratios of the association with DM were 2.26 (2.01, 2.55) for dementia-related and 1.97 (1.89, 2.05) for the competing risk of non-dementia-related mortality. This association was strongest amongst participants with incident DM, younger age at baseline and higher alcohol consumption or who were overweight.

CONCLUSIONS

In the California Teachers Study, women with DM had increased risk of mortality due to both dementia and non-dementia causes; however, the risk of mortality due to dementia was elevated compared to non-dementia causes only amongst participants with incident DM.

Protocol for a single-arm, pilot trial of creatine monohydrate supplementation in patients with Alzheimer's disease

BACKGROUND

Impaired brain bioenergetics is a pathological hallmark of Alzheimer's disease (AD) and is a compelling target for AD treatment. Patients with AD exhibit dysfunction in the brain creatine (Cr) system, which is integral in maintaining bioenergetic flux. Recent studies in AD mouse models suggest Cr supplementation improves brain mitochondrial function and may be protective of AD peptide pathology and cognition.

AIMS

The Creatine to Augment Bioenergetics in Alzheimer's disease (CABA) study is designed to primarily assess the feasibility of supplementation with 20 g/day of creatine monohydrate (CrM) in patients with cognitive impairment due to AD. Secondary aims are designed to generate preliminary data investigating changes in brain Cr levels, cognition, peripheral and brain mitochondrial function, and muscle strength and size.

METHODS

CABA is an 8-week, single-arm pilot study that will recruit 20 patients with cognitive impairment due to AD. Participants attend five in-person study visits: two visits at baseline to conduct screening and baseline assessments, a 4-week visit, and two 8-week visits. Outcomes assessment includes recruitment, retention, and compliance, cognitive testing, magnetic resonance spectroscopy of brain metabolites, platelet and lymphocyte mitochondrial function, and muscle strength and morphology at baseline and 8 weeks.

DISCUSSION

CABA is the first study to investigate CrM as a potential treatment in patients with AD. The pilot data generated by this study are pertinent to inform the design of future large-scale efficacy trials.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05383833 , registered on 20 May 2022.

Creatine as a Therapeutic Target in Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, affecting approximately 6.5 million older adults in the United States. Development of AD treatment has primarily centered on developing pharmaceuticals that target amyloid-β (Aβ) plaques in the brain, a hallmark pathological biomarker that precedes symptomatic AD. Though recent clinical trials of novel drugs that target Aβ have demonstrated promising preliminary data, these pharmaceuticals have a poor history of developing into AD treatments, leading to hypotheses that other therapeutic targets may be more suitable for AD prevention and treatment. Impaired brain energy metabolism is another pathological hallmark that precedes the onset of AD that may provide a target for intervention. The brain creatine (Cr) system plays a crucial role in maintaining bioenergetic flux and is disrupted in AD. Recent studies using AD mouse models have shown that supplementing with Cr improves brain bioenergetics, as well as AD biomarkers and cognition. Despite these promising findings, no human trials have investigated the potential benefits of Cr supplementation in AD. This narrative review discusses the link between Cr and AD and the potential for Cr supplementation as a treatment for AD.

Higher Diet Quality in Latina Women during Pregnancy May Be Associated with Sociodemographic Factors

Acculturation contributes to low diet quality and can foster health inequities for Latina women during pregnancy. Conversely, nutrition literacy (NL) increases diet quality and could promote health equity. This study assessed the associations between the diet quality, acculturation, and NL of Latina women (n = 99) participating in the Assessment of Docosahexaenoic Acid On Reducing Early Preterm Birth (ADORE) study. Acculturation and nutrition literacy factored together tended to modify diet quality, but this was not statistically significant. Diet quality was associated with acculturation, age, and nativity. Most (76.8%) demonstrated low nutrition literacy. Women who were bicultural and were born in Latin American countries other than Mexico had lower diet quality scores than women who had lower acculturation and were born in Mexico. Women who were 35 years or older had better diet quality than those who were younger. Future studies are needed to explore diet quality differences for pregnant Latina women with high nutrition literacy and high acculturation, as well as for women from the Caribbean, Central and South American countries living in the US, to promote nutrition and maternal health for Latina women.

Milk intake enhances cerebral antioxidant (glutathione) concentration in older adults: A randomized controlled intervention study

Background

A major antioxidant, glutathione (GSH), is a key factor in the antioxidant defense mechanism against oxidative stress and aging-related functional declines. Our previous observational study showed positive correlations between brain GSH concentrations and dairy food consumption, particularly milk (p < 0.001), in older adults.

Objective

To investigate whether a recommended amount of milk intake (3 cups/day) in low dairy consumers enhances brain GSH concentrations through an intervention trial.

Methods

Seventy-three older adults (60–89 years) with a low dairy intake (≤1.5 servings/day) were randomized (5:2 ratio) in this 3-month randomized clinical trial. The intervention group was provided 1% milk weekly and instructed to consume 3 cups of milk/day for 3 months while the control group continued their habitual intake of total dairy ≤ 1.5 servings/day (<1 cup of milk/day). Brain GSH concentrations were measured in the fronto-parietal region using our unique 3 T magnetic resonance chemical shift imaging technique at baseline and 3 months.

Results

Among 73 randomized participants, 66 participants (49 intervention; 17 controls) completed the study. Milk intake in the intervention group increased from 0.2 ± 0.3 cups/day to 3.0 ± 0.6 cups/day (p < 0.001) between baseline and the end of the study, while milk intake in the control group did not differ throughout the study duration (0.4 ± 0.4 cups/day). The intervention group showed increases in brain GSH concentrations by 7.4 ± 11.7% (p < 0.001) in parietal and 4.7 ± 9.8% (p = 0.003) in fronto-parietal regions, and 4.6 ± 8.7% (p < 0.001) in overall brain concentration after the intervention compared with baseline, while the control group showed no changes.

Conclusion

This study provides evidence that milk serves as a good dietary source to increase and/or restore brain GSH concentrations in older adults. Identifying dietary sources that effectively enhance antioxidant defenses and neuroprotection could lead to the development of new strategies to promote brain health in the aging population.

Clinical trial registration

[https://ClinicalTrials.gov], identifier [NCT02957422].

Potential for Ketotherapies as Amyloid-Regulating Treatment in Individuals at Risk for Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative condition characterized by clinical decline in memory and other cognitive functions. A classic AD neuropathological hallmark includes the accumulation of amyloid-β (Aβ) plaques, which may precede onset of clinical symptoms by over a decade. Efforts to prevent or treat AD frequently emphasize decreasing Aβ through various mechanisms, but such approaches have yet to establish compelling interventions. It is still not understood exactly why Aβ accumulates in AD, but it is hypothesized that Aβ and other downstream pathological events are a result of impaired bioenergetics, which can also manifest prior to cognitive decline. Evidence suggests that individuals with AD and at high risk for AD have functional brain ketone metabolism and ketotherapies (KTs), dietary approaches that produce ketone bodies for energy metabolism, may affect AD pathology by targeting impaired brain bioenergetics. Cognitively normal individuals with elevated brain Aβ, deemed “preclinical AD,” and older adults with peripheral metabolic impairments are ideal candidates to test whether KTs modulate AD biology as they have impaired mitochondrial function, perturbed brain glucose metabolism, and elevated risk for rapid Aβ accumulation and symptomatic AD. Here, we discuss the link between brain bioenergetics and Aβ, as well as the potential for KTs to influence AD risk and progression.

Relationship of fasting glucose and longitudinal Alzheimer's disease imaging markers

INTRODUCTION

Fasting glucose increases with age and is linked to modifiable Alzheimer's disease risk factors such as cardiovascular disease and Type 2 diabetes (T2D).

METHODS

We leveraged available biospecimens and neuroimaging measures collected during the Alzheimer's Prevention Through Exercise (APEx) trial (n = 105) to examine the longitudinal relationship between change in blood glucose metabolism and change in regional cerebral amyloid deposition and gray and white matter (WM) neurodegeneration in older adults over 1 year of follow-up.

RESULTS

Individuals with improving fasting glucose (n = 61) exhibited less atrophy and regional amyloid accumulation compared to those whose fasting glucose worsened over 1 year (n = 44). Specifically, while individuals with increasing fasting glucose did not yet show cognitive decline, they did have regional atrophy in the hippocampus and inferior parietal cortex, and increased amyloid accumulation in the precuneus cortex. Signs of early dementia pathology occurred in the absence of significant group differences in insulin or body composition, and was not modified by apolipoprotein E ε4 carrier status.

DISCUSSION

Dysregulation of glucose in late life may signal preclinical brain change prior to clinically relevant cognitive decline. Additional work is needed to determine whether treatments specifically targeting fasting glucose levels may impact change in brain structure or cerebral amyloid in older adults.

Correlation of Skin Carotenoid Content with 3-Day Dietary Intake in Community Dwelling Older Adults

Pressure-mediated reflection spectroscopy (RS) measures skin carotenoid content (SCC). Continued validation of this method is pertinent to validate its use as an objective measure of fruit and vegetable intake. This study aimed to assess relationships between SCC scores and self-reported dietary carotenoid intake from 3-day food records in community dwelling older adults. This was a cross-sectional analysis of baseline data among cognitively normal older adults (n=95) participating in the Nutrition Interventions for Cognitive Enhancement (NICE) study. Food-derived vitamin A (R=0.24, p<0.05) and food plus supplemental vitamin A (R=0.29, p<0.01) were correlated with SCC. All food-derived carotenoids (R: 0.20-0.39, p<0.05) except beta-cryptoxanthin and lycopene were correlated with SCC. Lutein + zeaxanthin from food more strongly correlated with SCC (R=0.38, p<0.001) than combined food plus supplemental intake (R=0.31, p=0.002). Correlations for total fruit and SCC (R=0.23, p=0.02), total vegetable and SCC (R= 0.31, p=0.002), and combined total fruit and vegetable and SCC (R=0.35, p<0.001) were significant; no sub-categories of fruit or vegetables except dark green vegetables (Rho=0.4, p<0.001) had significant correlations with SCC. The current study demonstrates RS-derived SCC scores correlate with 3-day self-reported intakes of F/V and certain carotenoids in community dwelling older adults.

US Older Adults That Consume Avocado or Guacamole Have Better Cognition Than Non-consumers: National Health and Nutrition Examination Survey 2011-2014

Purpose: The goal of this study is to examine how avocado relates to cognitive function among older adults. Methods: A total of 2,886 National Health and Nutrition Examination Survey 2011-2014 participants aged 60 or older met the eligibility criteria and were included of our cross-sectional study. Participants were binarily classified as avocado consumers (i.e., reported consuming any avocado/guacamole in either 24-h dietary recalls) or non-consumers. Cognitive performance was evaluated with: Consortium to Establish a Registry for Alzheimer's disease (CERAD)-immediate and delayed recall (IWR/DWR), the Animal Fluency test, and the Digit Symbol Substitution Test. We calculated the education-dependent z-scores for each subject because education level can impact cognitive function. Global cognitive score, an average of the z-scores for each cognitive test, was calculated in participants who had completed all four tests. To account for relevant covariates, we tested for mean differences in cognition between consumers and non-consumers using independent sample t-tests and ANCOVA, special cases of ordinary least squares regression. Results: Avocado consumers had significantly better cognitive scores across all cognitive tests and the global cognition score (p < 0.05) in the unadjusted model. Some mean differences attenuated after adjusting for potential confounders, but others remained significant. Compared to non-consumers, avocado consumers had significantly higher z-scores of 0.15, 0.15, and 0.11 for CERAD IWR and DWR, and global cognition score, respectively (all p < 0.05 in adjusted models). Conclusion: Avocado consumption was associated with significantly better IWR, DWR, and the overall global cognition score, which remained significant when controlling for all relevant confounders.

High Glycemic Diet Is Related to Brain Amyloid Accumulation Over One Year in Preclinical Alzheimer's Disease

Objective: To test the hypothesis that high glycemic diet is related to 1-year change in brain amyloid based on our prior cross-sectional evidence that high glycemic diet is associated with brain amyloid.

Methods: This longitudinal, observational study assessed the relationship between reported habitual consumption of a high glycemic diet (HGDiet) pattern and 1-year brain amyloid change measured by Florbetapir F18 PET scans in 102 cognitively normal older adults with elevated or sub-threshold amyloid status that participated in a 1-year randomized, controlled exercise trial at the University of Kansas Medical Center in Kansas City.

Results: Among all participants (n = 102), higher daily intake of the HGDiet pattern (β = 0.06, p = 0.04), sugar (β = 0.07, p = 0.01), and total carbohydrate (β = 0.06, p = 0.04) were related to more precuneal amyloid accumulation. These relationships in the precuneus were accentuated in participants with elevated amyloid at enrollment (n = 70) where higher intake of the HGDiet pattern, sugar, and carbohydrate were related to more precuneal amyloid accumulation (β = 0.11, p = 0.01 for all measures). In individuals with elevated amyloid, higher intake of the HGDiet pattern was also related to more amyloid accumulation in the lateral temporal lobe (β = 0.09, p < 0.05) and posterior cingulate gyrus (β = 0.09, p < 0.05) and higher sugar and carbohydrate intake were also related to more amyloid accumulation in the posterior cingulate gyrus (β = 0.10, p < 0.05 for both measures).

Conclusion: This longitudinal observational analysis suggests that a high glycemic diet relates to higher brain amyloid accumulation over 1 year in regions of the temporoparietal cortex in cognitively normal adults, particularly in those with elevated amyloid status. Further studies are required to assess whether there is causal link between a high glycemic diet and brain amyloid.

Clinical Trial Registration:ClinicalTrials.gov, Identifier (NCT02000583).

The Ketogenic Diet in the Treatment of Post-concussion Syndrome-A Feasibility Study

Concussion is the most common form of mild traumatic brain injury (mTBI). Although most patients' symptoms resolve within a month, patients with post-concussion syndrome (PCS) may continue to experience symptoms for years and have limited treatment options. This pilot study assessed the feasibility and symptom-related effects of a ketogenic diet (KD) in patients with PCS symptoms. The Ketogenic Diet in Post-Concussion Syndrome (KD-PCS) was a single-arm trial of a 2-month KD high in non-starchy vegetables and supplemented with medium-chain triglyceride (MCT) oil. Macronutrient targets were ≥70% fat, ≤10% carbohydrate, and the remainder as protein as energy. We assessed feasibility by daily self-reported measure of urine acetoacetate and collection of 3-day food records and serum beta-hydroxybutyrate at multiple timepoints. We assessed symptoms by administering the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and Modified Balance Error Scoring System (M-BESS) at baseline and month 2 and the Post-Concussion Symptom Scale (PCSS) at baseline, month 1, and month 2. Fourteen participants enrolled in the KD-PCS. Twelve participants completed the study and 11 implemented the KD (73% fat, 9% carbohydrate, and 18% protein) and achieved ketosis. One participant complained of MCT-related diarrhea that resolved and another reported nausea and fatigue that resulted in withdrawal from the study. Among compliant participants, the visual memory domain of the ImPACT improved by 12 points (p = 0.02) and PCSS scores improved by 9 points, although not statistically significant. This pilot trial suggests that the KD is a feasible experimental treatment for PCS and justifies further study of its efficacy.

An Experimental Ketogenic Diet for Alzheimer Disease Was Nutritionally Dense and Rich in Vegetables and Avocado

BACKGROUND

The ketogenic diet (KD) has gained interest as a potential therapy for numerous conditions; however, studies rarely report the food and micronutrient profile of the diet.

OBJECTIVE

The aim of this study was to report changes in food selection and nutritional quality from the baseline diet (BD) to a KD therapy in participants with Alzheimer disease (AD).

METHODS

Fifteen AD patients participated in a single-arm clinical trial to assess the feasibility of a 3-mo KD intervention. A registered dietitian instructed participant study partners to assist participants with a self-selected, nutritionally dense KD. We collected food and nutrient intake via monthly 3-d food records. Serum β-hydroxybutyrate was measured within 48 h of each 3-d food record to assess ketosis status. Food records before KD initiation characterized the BD. Food records during the intervention coincident with the most robust ketosis characterized the KD. Principal components analysis identified foods affiliated with the BD and KD. Mean food and nutrient intake change was tested by the Kruskal-Wallis test for variance with significance set at P ≤ 0.025.

RESULTS

Ten participants adhered to the KD. Study partners provided complete food records for 6 KD-adherent individuals. The KD was characterized by increased medium-chain triglyceride (MCT) oil, nonstarchy vegetables, butter, eggs, olive oil, avocados, and nuts and seeds with practical elimination of potatoes, grains, red meat, sugar-sweetened beverages, and desserts. Fruit intake, including avocado, was similar between diets. Nonstarchy vegetable intake increased from 1.2 servings/d to 4.3 servings/d (P < 0.01) on the KD. Micronutrient intake was similar between diets, meeting Dietary Reference Intakes for most nutrients. Between diets, the KD was associated with increased intake of choline and vitamin K and decreased intake of manganese and fiber.

CONCLUSION

As a potential therapy in AD, the KD can be nutritionally dense with high intake of vegetables and substantial variety. This trial was registered at clinicaltrials.gov as NCT03690193.

Feasibility and efficacy data from a ketogenic diet intervention in Alzheimer's disease

Introduction

We assessed the feasibility and cognitive effects of a ketogenic diet (KD) in participants with Alzheimer's disease.

Methods

The Ketogenic Diet Retention and Feasibility Trial featured a 3-month, medium-chain triglyceride-supplemented KD followed by a 1-month washout in clinical dementia rating (CDR) 0.5, 1, and 2 participants. We obtained urine acetoacetate, serum β-hydroxybutyrate, food record, and safety data. We administered the Alzheimer's Disease Assessment Scale-cognitive subscale and Mini-Mental State Examination before the KD, and following the intervention and washout.

Results

We enrolled seven CDR 0.5, four CDR 1, and four CDR 2 participants. One CDR 0.5 and all CDR 2 participants withdrew citing caregiver burden. The 10 completers achieved ketosis. Most adverse events were medium-chain triglyceride-related. Among the completers, the mean of the Alzheimer's Disease Assessment Scale-cognitive subscale score improved by 4.1 points during the diet (P = .02) and reverted to baseline after the washout.

Discussion

This pilot trial justifies KD studies in mild Alzheimer's disease.

A high-glycemic diet is associated with cerebral amyloid burden in cognitively normal older adults

Background: Little is known about the relation between dietary intake and cerebral amyloid accumulation in aging.Objective: We assessed the association of dietary glycemic measures with cerebral amyloid burden and cognitive performance in cognitively normal older adults.Design: We performed cross-sectional analyses relating dietary glycemic measures [adherence to a high-glycemic-load diet (HGLDiet) pattern, intakes of sugar and carbohydrates, and glycemic load] with cerebral amyloid burden (measured by florbetapir F-18 positron emission tomography) and cognitive performance in 128 cognitively normal older adults who provided eligibility screening data for the University of Kansas's Alzheimer's Prevention through Exercise (APEX) Study. The study began in November 2013 and is currently ongoing.Results: Amyloid was elevated in 26% (n = 33) of participants. HGLDiet pattern adherence (P = 0.01), sugar intake (P = 0.03), and carbohydrate intake (P = 0.05) were significantly higher in participants with elevated amyloid burden. The HGLDiet pattern was positively associated with amyloid burden both globally and in all regions of interest independently of age, sex, and education (all P ≤ 0.001). Individual dietary glycemic measures (sugar intake, carbohydrate intake, and glycemic load) were also positively associated with global amyloid load and nearly all regions of interest independently of age, sex, and educational level (P ≤ 0.05). Cognitive performance was associated only with daily sugar intake, with higher sugar consumption associated with poorer global cognitive performance (global composite measure and Mini-Mental State Examination) and performance on subtests of Digit Symbol, Trail Making Test B, and Block Design, controlling for age, sex, and education.Conclusion: A high-glycemic diet was associated with greater cerebral amyloid burden, which suggests diet as a potential modifiable behavior for cerebral amyloid accumulation and subsequent Alzheimer disease risk. This trial was registered at clinicaltrials.gov as NCT02000583.

Repeatability of movement behaviour in a wild salmonid revealed by telemetry

Movement estimates derived from sub-daily tracking of radio-tagged bull trout Salvelinus confluentus on the Columbia River, British Columbia, Canada, were used to test whether interindividual variation in behaviour was repeatable among contexts, both short- and long-term. Interindividual variation in S. confluentus behaviour was consistent across contexts. These findings emphasize the potential for telemetry as a tool in animal personality and temperament research.

Failure to engage the public in issues related to inland fishes and fisheries: strategies for building public and political will to promote meaningful conservation

Generating awareness of environmental conservation issues among the public is essential if there is an expectation of them to alter their behaviour, facilitate informed decisions and engage governments or regulatory authorities to take action. There are, however, exceedingly few public engagement success stories related to inland fishes and fisheries policy and resource allocation decisions. Inland aquatic resources and their associated fisheries provide employment, recreation, culture and, in developing regions, a considerable proportion of human nutrition and food security. Freshwater fishes are incredibly diverse but are among the most endangered organisms globally. Many threats to inland fisheries are driven largely by externalities to inland fisheries. The purpose of this paper is to draw attention to the role and plight of inland fishes and fisheries, and the need to generate the public and political will necessary to promote meaningful conservation. With this paper, the extent to which the scientific and environmental management communities have failed to engage the public in issues related to inland fishes and fisheries is characterized. Next, the barriers or factors that serve as the basis for the problem with public engagement are identified. The paper concludes by identifying strategies, including those focused on environmental education initiatives, for building the public and political will necessary to promote meaningful conservation of inland fishes and fisheries in developed and developing countries. Scientists, environmental managers, non-governmental organizations, politicians, regulatory authorities and the media all have important roles to play in overcoming challenges to inland fisheries. Failure to engage the public in freshwater conservation and management issues will impede efforts to stem the loss of freshwater habitats, fisheries and aquatic biodiversity. Thankfully, there are opportunities to learn from success stories related to other environmental issues and initiatives that have been successful in marine fish conservation.

'Learn the signs. Act early': a campaign to help every child reach his or her full potential

OBJECTIVE

To examine the application of a social marketing approach to increase the early identification and treatment of autism and other developmental disorders.

STUDY DESIGN

The intervention used formative research, behaviour change theory and traditional social marketing techniques to develop a campaign targeting parents, healthcare professionals and early educators to increase awareness of autism and other developmental delays, and to prompt action if a developmental delay was suspected.

METHOD

Using social marketing principles, the Centers for Disease Control and Prevention applied baseline research with the target audiences to understand the barriers and motivators to behaviour change, which included a lack of knowledge and resources (barriers), along with a willingness to learn and do more (motivators). Focus group testing of potential campaign concepts led to one particular approach and accompanying images, which together increased perceived severity of the problem and encouraged taking action. The audience research also helped to shape the marketing mix (product, price, place and promotion).

RESULTS

Three-year follow-up research in this case study indicates a significant change in parent target behaviours, particularly among parents aware of the campaign, and substantially more healthcare professionals believe that they have the resources to educate parents about monitoring their child's cognitive, social and physical development. Qualitative results from early educators and childcare professional associations have been positive about products developed for daycare settings.

CONCLUSION

The application of social marketing principles, behavior change theory and audience research was an effective approach to changing behaviours in this case. Understanding what the target audiences want and need, looking beyond parents to engage healthcare professionals and early educators, and engaging many strategic partners to extend the reach of the message helped campaign planners to develop a campaign that resonated with the target audiences and, importantly, moved them towards action.

Patients' rights on the World Wide Web

Managed care reform, commonly referred to as "patients' rights" legislation, has become a hot topic. Many groups, including consumers, health care professionals, employers, managed care organizations, political parties, and government agencies, have strong opinions about measures that should be taken and what the outcomes of these measures might be. Those investigating this multidisciplinary topic will want to examine health care administration, ethics, health services research, and political science sources. Web resources covered in this article include: clearinghouses; government agencies; federal legislative and legal sites; and home pages of professional and trade associations, policy research institutes, and consumer advocacy organizations.

A cGMP-dependent protein kinase is implicated in wild-type motility in C. elegans

In mammals, cyclic GMP and cGMP-dependent protein kinases (cGKs) have been implicated in the regulation of many neuronal functions including long-term potentiation and long-term depression of synaptic efficacy. To develop Caenorhabditis elegans as a model system for studying the neuronal function of the cGKs, we cloned and characterized the cgk-1 gene. A combination of approaches showed that cgk-1 produces three transcripts, which differ in their first exon but are similar in length. Northern analysis of C. elegans RNA, performed with a probe designed to hybridize to all three transcripts, confirmed that a major 3.0 kb cgk-1 transcript is present at all stages of development. To determine if the CGK-1C protein was a cGMP-dependent protein kinase, CGK-1C was expressed in SF:9 cells and purified. CGK-1C shows a K(a) of 190 +/- 14 nM for cGMP and 18.4 +/- 2 microM for cAMP. Furthermore, CGK-1C undergoes autophosphorylation in a cGMP-dependent manner and is inhibited by the commonly used cGK inhibitor, KT5823. To determine which cells expressed CGK-1C, a 2.4-kb DNA fragment from the promoter of CGK-1C was used to drive GFP expression. The CGK-1C reporter construct is strongly expressed in the ventral nerve cord and in several other neurons as well as the marginal cells of the pharynx and intestine. Finally, RNA-mediated interference of CGK-1 resulted in movement defects in nematode larvae. These results provide the first demonstration that cGMP-dependent protein kinase is present in neurons of C. elegans and show that this kinase is required for normal motility.

The amino-terminal cyclic nucleotide binding site of the type II cGMP-dependent protein kinase is essential for full cyclic nucleotide-dependent activation

For the type I cGMP-dependent protein kinases (cGKIalpha and cGKIbeta), a high affinity interaction exists between the C2 amino group of cGMP and the hydroxyl side chain of a threonine conserved in most cGMP binding sites. To examine the effect of this interaction on ligand binding and kinase activation in the type II isozyme of cGMP-dependent protein kinase (cGKII), alanine was substituted for the conserved threonine or serine. cGKII was found to require the C2 amino group of cGMP and its cognate serine or threonine hydroxyl for efficient cGMP activation. Of the two binding sites, disruption of cGMP-specific binding in the NH(2)-terminal binding site had the greatest effect on cGMP-dependent kinase activation, like cGKI. However, ligand dissociation studies showed that the location of the rapid and slow dissociation sites of cGKII was reversed relative to cGKI. Another set of mutations that prevented cyclic nucleotide binding demonstrated the necessity of the NH(2)-terminal, rapid dissociation binding site for cyclic nucleotide-dependent activation of cGKII. These findings suggest distinct mechanisms of activation for cGKII and cGKI isoforms. Because cGKII mediates the effects of heat-stable enterotoxins via the cystic fibrosis transmembrane regulator Cl(-) channel, these findings define a structural target for drug design.

Composite method to quantify powder flow as a screening method in early tablet or capsule formulation development

The flow properties of typical tablet and capsule formulation excipients, active compounds, and representative formulation blends were tested with current and novel flow measurement techniques to identify a reliable bench test to quantify powder flow as a screening method in early tablet and capsule formulation development. Test methods employed were vibrating spatula, critical orifice, angle of repose, compressibility index, and avalanching analysis. Powder flow results from each method were compiled in a database, sorted, and compared. An empirical composite index was established and powder flow was ranked in accordance with formulator experience. Principal components analyses of the angle of repose, percent compressibility, and critical orifice of the powder materials were also performed. The first principal component accounted for 72.8% of data variability; scores associated with this principal component score can serve as an index of flowability. Data generated from vibrating spatula and avalanching methods were not reproducible and were inconsistent with formulator experience and cited vendor references for flow. Improvements of test instruments and further studies are necessary for better assessment of these approaches.

Supercritical fluid extraction of 2,4,6-trichloroanisole from cork stoppers

2,4,6-Trichloroanisole (TCA) is the compound most often associated with cork taint in wines and has been shown to have a very low sensory threshold ( approximately 5 ng/L in wine). A supercritical fluid extraction (SFE) method for TCA in bark cork stoppers was developed with quantification via gas chromatography-mass spectrometry with selected ion monitoring. Supercritical carbon dioxide functioned as the extracting solvent, and temperature and pressure were optimized for the extraction. The method was validated using the stable isotope (2)H(5)-TCA as the internal standard. Recovery of TCA from spiked corks was found to be within 1-4% of the theoretical concentration with a coefficient of variation ranging from 2.6 to 9.7%. TCA levels in corks pulled from wines described as tainted by experienced judges ranged from 0.13 to 2.11 microg/g of cork. The SFE procedure offers a rapid, quantitative, nearly solvent-free, and automated method for the extraction of TCA from complex solid matrices such as cork.

Genetic structure of the world's polar bear populations

We studied genetic structure in polar bear (Ursus maritimus) populations by typing a sample of 473 individuals spanning the species distribution at 16 highly variable microsatellite loci. No genetic discontinuities were found that would be consistent with evolutionarily significant periods of isolation between groups. Direct comparison of movement data and genetic data from the Canadian Arctic revealed a highly significant correlation. Genetic data generally supported existing population (management unit) designations, although there were two cases where genetic data failed to differentiate between pairs of populations previously resolved by movement data. A sharp contrast was found between the minimal genetic structure observed among populations surrounding the polar basin and the presence of several marked genetic discontinuities in the Canadian Arctic. The discontinuities in the Canadian Arctic caused the appearance of four genetic clusters of polar bear populations. These clusters vary in total estimated population size from 100 to over 10 000, and the smallest may merit a relatively conservative management strategy in consideration of its apparent isolation. We suggest that the observed pattern of genetic discontinuities has developed in response to differences in the seasonal distribution and pattern of sea ice habitat and the effects of these differences on the distribution and abundance of seals.

Interferon-gamma-secreting T-cell populations in rejecting murine cardiac allografts: assessment by flow cytometry

Interplay between T-helper-1 (Th1) and T-helper-2 (Th2) cells is considered important in the development of acute allograft rejection and many other immune-mediated disease processes. Existing methods for evaluating expression of Th1 and Th2 cytokines, including reverse transcriptase polymerase chain reaction (RT-PCR), RNase protection assay (RPA), immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) all have limitations; alternate techniques to quantify cell populations expressing specific cytokine proteins, generate statistically analyzable data, and allow simultaneous identification of cytokine-secreting cell type are needed. To this end, we adapted a flow cytometric technique for intracellular cytokine immunofluorescence staining for use with cells isolated from solid tissue. To demonstrate the utility of the method, we determined the number of CD4+ and CD8+ cells secreting the prototypical Th1 and Th2 cytokines, interferon (IFN)-gamma, and interleukin (IL)-4 in acutely rejecting murine cardiac allografts. We also measured the cytokine production via ELISA, RPA, and semiquantitative competitive RT-PCR. The number of CD4+ cells producing IFN-gamma increased as rejection proceeded, in agreement with previous data; we detected no IL-4 production at any time, although relatively low numbers of IL-10-producing cells were identified. In addition, a high percentage of CD8+ cells, which outnumber CD4+ cells at day 6 after transplant, also produce IFN-gamma, suggesting that cytotoxic lymphocytes contribute significantly to the local cytokine milieu. This new application of intracellular cytokine staining provides a powerful methodology for studying transplantation immunology. The method may also be easily adapted to the study of other immune-mediated processes.

The practical effects of errors in reference lists in nursing research journals

BACKGROUND

Previous studies have noted the prevalence of errors in journal reference lists, including nursing journals, but an in-depth study of nursing research journals has not been repeated.

OBJECTIVES

The purpose of this study was to determine the number and types of errors in nursing research journal reference lists.

METHOD

A stratified random sample of 262 references from three nursing research journals was obtained. References were compared with the actual articles, books, and chapters cited, or with photocopies obtained via interlibrary loan. Error rates were calculated.

RESULTS

The overall error rate was 45.8%; 38.3% of all references contained at least one major error, and 13.8% of all references contained at least one minor error.

CONCLUSIONS

The overall rate of reference errors falls within the range exhibited by recent studies of the medical and dental literature but exceeds the rates found in studies of nursing journals and veterinary medicine journals. Researchers need to consider the number and types of errors involved when using reference lists in their research.

Chlorinated hydrocarbon contaminants in polar bears from eastern Russia, North America, Greenland, and Svalbard: biomonitoring of Arctic pollution

Adipose tissue samples from polar bears (Ursus maritimus) were obtained by necropsy or biopsy between the spring of 1989 to the spring of 1993 from Wrangel Island in Russia, most of the range of the bear in North America, eastern Greenland, and Svalbard. Samples were divided into 16 regions corresponding as much as possible to known stocks or management zones. Concentrations of dieldrin (DIEL), 4,4'-DDE (DDE), sum of 16 polychlorinated biphenyl congeners (sigma PCB), and sum of 11 chlordane-related compounds and metabolites (sigma CHL) were determined. In order to minimize the effect of age, only data for adults (320 bears age 5 years and older) was used to compare concentrations among regions. Concentrations of sigma PCB were 46% higher in adult males than females, and there was no significant trend with age. Concentrations of sigma CHL were 30% lower in adult males than females. Concentrations of sigma PCB, sigma CHL, and DDE in individual adult female bears were standardized to adult males using factors derived from the least-square means of each sex category, and geometric means of the standardized concentrations on a lipid weight basis were compared among regions. Median geometric mean standardized concentrations (lipid weight basis) and ranges among regions were as follows: sigma PCB, 5,942 (2,763-24,316) micrograms/kg; sigma CHL, 1,952 (727-4,632) micrograms/kg; DDE, 219 (52-560) micrograms/kg; DIEL, 157 (31-335) micrograms/kg. Geometric mean sigma PCB concentrations in bears from Svalbard, East Greenland, and the Arctic Ocean near Prince Patrick Island in Canada were similar (20,256-24,316 micrograms/kg) and significantly higher than most other areas. Atmospheric, oceanic, and ice transport, as well as ecological factors may contribute to these high concentrations of sigma PCB. sigma CHL was more uniformly distributed among regions than the other CHCs. Highest sigma CHL concentrations were found in southeastern Hudson Bay, which also had the highest DDE and DIEL concentrations. In general, concentrations of sigma CHL, DDE, and DIEL were higher in eastern than western regions, suggesting an influence of North American sources. Average sigma PCB concentrations in bears from the Canadian Arctic were similar to those in 1982-84, while average sigma CHL and DDE concentrations were 35-44% lower and DIEL was 90% lower. However, the significance of these temporal trends during the 1980s is not conclusive because of the problems of comparability of data.

Coronary arteriosclerosis after T-cell-mediated injury in transplanted mouse hearts: role of interferon-gamma

This study evaluated the contribution of acute parenchymal rejection and interferon (IFN)-gamma to the development of graft arterial disease (GAD) in totally allogeneic murine cardiac transplants. BALB/c (H-2d) hearts were transplanted into wild-type C57BL/6 (B6, H-2b) or B6 IFN-gamma-deficient (GKO) recipient mice. Assessing the role of acute parenchymal rejection in the GAD process involved two different immunosuppression protocols using anti-CD4 and -CD8 monoclonal antibodies (MAbs): virtually complete long-term immunosuppression (denoted as complete immunosuppression) was achieved by administering both MAbs 6, 3, and 1 day before transplantation and weekly thereafter; in contradistinction, a single, early, transient episode of rejection (transient rejection) was attained by administering MAbs beginning 4 days after transplant and then at weekly intervals. The extent and duration of T cell depletion under these two regimens were evaluated using flow cytometric analysis of peripheral blood lymphocytes. After a single injection of MAbs, peripheral blood CD4+ and CD8+ T cell depletion was approximately 98% at 1 week and approximately 88% at 2 weeks. After three injections (analogous to days 6, 3, and 1 before transplant), peripheral blood CD4+ and CD8+ T cell depletion was >98% at 2 weeks and approximately 87% at 4 weeks. Functioning cardiac allografts were removed at 8 and 12 weeks after transplant and analyzed by hematoxylin and eosin, elastic tissue, and immunohistochemical stains, and the severity of parenchymal rejection versus GAD was scored. With complete immunosuppression (antibody before and after transplant), BALB/c allografts showed little parenchymal rejection or GAD, suggesting that persistent depletion of T cells blocked subsequent development of GAD. However, even a single transient acute rejection episode allowed the subsequent development of GAD accompanied by augmented major histocompatibility complex (MHC) class II, VCAM-1, and ICAM-1 expression at 12 weeks; these allografts showed no residual CD4+ or CD8+ T cells. In comparison, allografts undergoing transient rejection in GKO recipients did not develop GAD, despite persistent macrophage and natural killer cell (NK) infiltrates comparable to those seen in wild-type recipients. Moreover, the arterioles of hearts transplanted into GKO recipients showed no or minimal increases in MHC class II, ICAM-1, and VCAM-1 relative to baseline expression. In conclusion, a single episode of allogeneic injury mediated by T cells suffices to evoke subsequent graft arteriosclerosis, even in the absence of additional T-cell-mediated injury, and the process appears to depend on IFN-gamma.

Facilitation and inhibition of the acoustic startle reflex in the rat after a momentary increase in background noise level

Small increments in background noise were shown to increase the amplitude of a subsequently elicited acoustic startle reflex (ASR) in rats by as much as 100% under optimal conditions. Increment lead time (5-160 ms) and level (1.5-15 dB), initial noise level (30-70 dB), startle level (95-125 dB), number of test days (1-5), and drug condition (diazepam or saline ip) were varied in 6 experiments. Prepulse facilitation (PPF), measured by difference scores, was greatest for intermediate increments (3 dB) and lead times (20-40 ms) and was replaced by prepulse inhibition (PPI) for higher values, especially in the later test days. Diazepam reduced baseline ASR and diminished PPI, but it did not affect PPF. These data argue against hypotheses that attribute PPF of this sort to either temporal integration within the ASR pathways or to the elicitation of a nonspecific arousal reaction by the prepulse.

Comparison of the performance of two sample thieves for the determination of the content uniformity of a powder blend

The objective of this study was to compare the performance of two sample thieves (plug and grain) to determine the content uniformity of a powder blend. The powder blend was prepared by mixing 2% drug substance with the remaining excipients in a tumble blender for 30 min. Samples were taken at 10 locations in the blender using both thieves. The performance of each sample thief was assessed based on the respective content uniformity values and relative standard deviations obtained for each device, as well as the content uniformity values reported following analysis of the resulting compressed tablets. The relative standard deviation values for blend samples taken with the plug thief were approximately half of those obtained using the grain thief. The superior performance of the plug thief in this study is attributed to the static charge acquired by the microcrystalline cellulose, which leads to poor flow characteristics. This impeded the flow of the blend into the sample chamber of the grain thief resulting in segregation and variable content uniformity results. The plug thief, which does not require powder flow to obtain a sample, performs better for this formulation. The selection of a sampling thief should be assessed on a case-by-case basis. Superior performance is expected for the plug thief when poor flowing, compressible blends are sampled.

Facilitation and inhibition of the acoustic startle reflex in the rat after a momentary increase in background noise level

Small increments in background noise were shown to increase the amplitude of a subsequently elicited acoustic startle reflex (ASR) in rats by as much as 100% under optimal conditions. Increment lead time (5-160 ms) and level (1.5-15 dB), initial noise level (30-70 dB), startle level (95-125 dB), number of test days (1-5), and drug condition (diazepam or saline ip) were varied in 6 experiments. Prepulse facilitation (PPF), measured by difference scores, was greatest for intermediate increments (3 dB) and lead times (20-40 ms) and was replaced by prepulse inhibition (PPI) for higher values, especially in the later test days. Diazepam reduced baseline ASR and diminished PPI, but it did not affect PPF. These data argue against hypotheses that attribute PPF of this sort to either temporal integration within the ASR pathways or to the elicitation of a nonspecific arousal reaction by the prepulse.

Interferon-gamma deficiency prevents coronary arteriosclerosis but not myocardial rejection in transplanted mouse hearts

We have hypothesized that T cell cytokines participate in the pathogenesis of graft arterial disease (GAD). This study tested the consequences of IFN-gamma deficiency on arterial and parenchymal pathology in murine cardiac allografts. Hearts from C-H-2(bm12)KhEg (bm12, H-2(bm12)) were transplanted into C57/B6 (B6, H-2(b)), wild-type, or B6 IFN-gamma-deficient (GKO) recipients after immunosuppression by treatment with anti-CD4 and anti-CD8 mAbs. In wild-type recipients, myocardial rejection peaked at 4 wk, (grade 2. 1+/-0.3 out of 4, mean+/-SEM, n = 9), and by 8-12 wk evolved coronary arteriopathy. At 12 wk, the GAD score was 1.4+/-0.3, and the parenchymal rejection grade was 1.2+/-0.3 (n = 8). In GKO recipients of bm12 allografts, myocardial rejection persisted at 12 wk (grade 2.5+/-0.3, n = 6), but no GAD developed (score: 0.0+/-0.0, n = 6, P < 0.01 vs. wild-type). Mice treated with anti-IFN-gamma mAbs showed similar results. Isografts generally showed no arterial changes. In wild-type recipients, arterial and parenchymal cells showed increased MHC class II molecules, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 compared to normal or isografted hearts. The allografts in GKO recipients showed attenuated expression of these molecules (n = 6). Thus, development of GAD, but not parenchymal rejection, requires IFN-gamma. Reduced expression of MHC antigens and leukocyte adhesion molecules may contribute to the lack of coronary arteriopathy in hearts allografted into GKO mice.

Effects of single and repeated exposure to apomorphine on the acoustic startle reflex and its inhibition by a visual prepulse

The acoustic startle reflex (ASR) is inhibited by startle-irrelevant stimuli that briefly precede reflex elicitation. This effect, prepulse inhibition (PPI), is reduced in strength for animals that have received dopamine agonists, such as apomorphine (APO). Reduction in PPI is most evident for weak masked noise prepulses, thus suggesting that APO disrupts the reception of stimuli to the extent that they present a low signal-to-noise ratio. Here we examine the effect of APO on PPI produced by non-masked visual prepulses. Light flashes were given at two intensities, 40, 70, 110, or 220 ms before ASR elicitation. In phase 1 (5 weeks in duration) half of the animals received one weekly injection of APO (0.5 mg/kg, IP) and one of vehicle (VEH), while the other half received two injections of VEH. Within these groups, half were tested 30 min after the injections, the other half kept test naive (four groups total). In phase 2, following a 4-week rest, all groups were tested after a low dose of APO (0.1 mg/kg) and VEH, 1 week apart. APO eliminated PPI for a dim flash and reduced PPI for a brighter flash to a level normally obtained with the dim flash, while increasing both ASR control values and activity. The bright light was maximally effective at a lead time of 70 ms and APO did not alter this value. Because in general the time of maximal inhibition varies with prepulse intensity for visual stimuli, the finding that the time of the peak remained constant reveals that APO has its effect on inhibition rather than on effective stimulus intensity. In phase 2, APO reduced PPI with no sign of sensitization from past drug exposure. However, APO increased the ASR only in groups previously exposed to APO, indicating behavioral sensitization. The differential effects of repeated exposure on these response measures suggest that neural substrates for the several behavioral effects of APO function at least in part independently.

Interaction of p72syk with the gamma and beta subunits of the high-affinity receptor for immunoglobulin E, Fc epsilon RI

Activation of protein tyrosine kinases is one of the initial events following aggregation of the high-affinity receptor for immunoglobulin E (Fc epsilon RI) on RBL-2H3 cells, a model mast cell line. The protein tyrosine kinase p72syk (Syk), which contains two Src homology 2 (SH2) domains, is activated and associates with phosphorylated Fc epsilon RI subunits after receptor aggregation. In this report, we used Syk SH2 domains, expressed in tandem or individually, as fusion proteins to identify Syk-binding proteins in RBL-2H3 lysates. We show that the tandem Syk SH2 domains selectively associate with tyrosine-phosphorylated forms of the gamma and beta subunits of Fc epsilon RI. The isolated carboxy-proximal SH2 domain exhibited a significantly higher affinity for the Fc epsilon RI subunits than did the amino-proximal domain. When in tandem, the Syk SH2 domains showed enhanced binding to phosphorylated gamma and beta subunits. The conserved tyrosine-based activation motifs contained in the cytoplasmic domains of the gamma and beta subunits, characterized by two YXXL/I sequences in tandem, represent potential high-affinity binding sites for the dual SH2 domains of Syk. Peptide competition studies indicated that Syk exhibits a higher affinity for the phosphorylated tyrosine activation motif of the gamma subunit than for that of the beta subunit. In addition, we show that Syk is the major protein in RBL-2H3 cells that is affinity isolated with phosphorylated peptides corresponding to the phosphorylated gamma subunit motif. These data suggest that Syk associates with the gamma subunit of the high-affinity receptor for immunoglobulin E through an interaction between the tandem SH2 domains of SH2 domains of Syk and the phosphorylated tyrosine activation motif of the gamma subunit and that Syk may be the major signaling protein that binds to Fc epsilon RI tyrosine activation motif of the gamma subunit and that Syk may be the major signaling protein that binds to Dc epsilon tyrosine activation motifs in RBL-2H3 cells.

Importance of hypothalamic function to stressor-induced responsiveness of the GABAA receptor in the cerebral cortex: a non-corticosterone influence

Catecholamine terminals in the paraventricular nucleus (PVN) of the hypothalamus of 60-day-old rats were destroyed by the stereotaxic injection of 6-hydroxydopamine into the PVN (6-OHDA; 9 micrograms/1.5 microliters bilaterally), and the rats were tested 2 weeks later. Lesions led to a 70% reduction of norepinephrine in the hypothalamus and a loss of dopamine-beta-hydroxylase immunoreactivity in the PVN. Furthermore, 6-OHDA lesions in the hypothalamus disrupted stressor-induced (15 min of restraint) changes in GABAA receptor function in the cerebral cortex (assessed by measuring chloride-facilitated benzodiazepine binding) but did not alter stressor-induced increases in plasma corticosterone levels. Additionally, the lesion did not change the responsiveness of the GABAA receptor to the corticosterone metabolite, allotetrahydrodeoxycorticosterone. These results indicate that stressor-induced changes in cortical GABAA receptor function are not driven by the stressor-induced release of corticosterone. A separate group of animals were tested for behavioral responses to challenge, and while 6-OHDA-induced lesions did not alter total scores in the test of environment-specific social interaction, the lesions did induce a change in composition of the behavior. Lesioned animals demonstrated increased physical (vigorous contact) interactions, similar to behavior previously observed in younger rats. The results of the behavioral study support a role for the GABAA receptor in the cerebral cortex in mediating appropriate behavioral responses to challenge in the adult rat. Thus, a hypothalamic lesion that prevented challenge-induced changes in GABAA receptor function in the cortex (with no change in the corticosterone response to the stressor) also led to altered behavioral responses to challenge.

Altered stressor-induced changes in GABAA receptor function in the cerebral cortex of adult rats exposed in utero to diazepam

Prenatal administration of the anxiolytic drug diazepam (DZP), 2.5 mg/kg) to the pregnant rat over gestational days 14-20 altered function and stressor-induced responsiveness of the GABAA receptor in the cerebral cortex of exposed animals as adults. In Experiment 1, the impact of 15 min of restraint on chloride-facilitated benzodiazepine binding was evaluated in male and female rats at 70-90 days of age. Early exposure to DZP led to an enhanced potency of chloride on binding in both males and females. In Experiment 2, GABA stimulation of 36chloride uptake was measured in male rats at 35 or 70 days of age following 10 min of forced swimming at ambient temperature. In control animals, stressor-induced changes in receptor function were not evident until 70 days, and in DZP-exposed rats the stressor had no effect on receptor function at either age. These changes in GABAA receptor responsiveness induced by early exposure to DZP may underlie the disrupted behavioral responses to environmental challenge that have been previously reported.

Cell-mediated cytotoxicity

Progress is being made in determining how cytotoxic cells are activated, the way the lethal hit is delivered and the subsequent events in the target cell. Several factors cloud the issue, including the heterogeneity of cytotoxic cells, differences between fresh cells and cell lines, and the possibility of single cells using multiple cytotoxic mechanisms. The most difficult task will be to define which cytotoxic mechanisms are significant in vivo.

Gastric stapling for morbid obesity: gastrointestinal response in a rat model

The adaptive response of the gastrointestinal tract to gastric stapling was studied in a Zucker (fafa) genetically obese rat model. The effects of gastric stapling in rats with a Roux-en-Y gastrojejunostomy were compared to Roux-en-Y and intact controls. Rats (225 to 275 g) were divided into three groups: group I (GI), Roux-en-Y, stapled, ad libitum fed; group II, Roux-en-Y, unstapled; and group III, intact (laparotomy only). Groups II and III were further subdivided into group IIA (GIIA) and group IIIA (GIIIA), pair-fed to GI; and group IIB (GIIB) and Group IIIB (GIIIB), fed ad libitum. All rats were fed a diet of liquid rat formula and rat food (50:50 cal ratio). After 2 wk rats were killed and the liver, pancreas, and stomach removed, weighed, and tissue taken for histology. The intestine was divided into three segments corresponding to the excluded segment (1, duodenum), transposed segment (2, jejunum), and ileal segment (3), with tissue taken for histology. Liver lipid, pancreatic amylase, serum amylase and gastrin, and intestinal mucosal protein and DNA were measured. Weight gain, g/14 days, was: GI, 24.1 +/- 7.8; GIIA, 17.0 +/- 2.0; GIIB, 42.6 +/- 4.8; GIIIA, 17.6 +/- 4.7; GIIIB, 54.6 +/- 8.9. All rats were in positive N balance. Liver weight and lipid were similar in all groups. Pancreatic mass was significantly increased in all Roux-en-Y animals, while amylase activity per g tissue was significantly less than in intact animals. Stapled rats had atrophy of the glandular portion of the stomach, decreased stomach mucosal weight, and lower serum gastrin concentration compared with all other rats (p less than 0.01). In stapled rats, segment weight and mucosal weight were lower in the excluded segment, and higher in the transposed segment, compared to all other rats. Tissue pathology was found only in stapled rats: gastric atrophy, focal fibrosis of gastric wall, peritonitis, minimal to mild multifocal hepatitis, and mild periductal fibrosis of the pancreas. There are significant early adaptive and pathological changes after gastric stapling in the rat.

Regulatory effects of fatty acids on decarboxylation of leucine and 4-methyl-2-oxopentanoate in the perfused rat heart

The regulatory effects of fatty acids on the oxidative decarboxylation of leucine and 4-methyl-2-oxopentanoate were investigated in the isolated rat heart. Infusion of the long-chain fatty acid palmitate resulted in both an inactivation of the branched-chain 2-oxo acid dehydrogenase and an inhibition of the measured metabolic flux through this enzyme complex. Pyruvate addition also caused both an inactivation and an inhibition of the flux through the complex. On the other hand, the medium-chain fatty acid octanoate caused an activation of and a stimulation of flux through the branched-chain 2-oxo acid dehydrogenase when the perfusion conditions before octanoate addition maintained the enzyme complex in its inactive state. When the enzyme complex was activated before octanoate infusion, this fatty acid caused a significant inhibition of the flux through the branched-chain 2-oxo acid dehydrogenase reaction. Inclusion of glucose in the perfusion medium prevented the octanoate-mediated activation of the branched-chain 2-oxo acid dehydrogenase.

Regulation of the glycine cleavage system in the isolated perfused rat liver

The catabolism of glycine in the isolated perfused rat liver was investigated by measuring the production of 14CO2 from [1-14C]- and [2-14C]glycine. Production of 14CO2 from [1-14C]glycine was maximal as the perfusate glycine concentration approached 10 mM and exhibited a maximal activity of 125 nmol of 14CO2 X g-1 X min-1 and an apparent Km of approximately 2 mM. Production of 14CO2 from [2-14C]glycine was much lower, approaching a maximal activity of approximately 40 nmol of 14CO2 X g-1 X min-1 at a perfusate glycine concentration of 10 mM, with an apparent Km of approximately 2.5 mM. Washout kinetic experiments with [1-14C]glycine exhibited a single half-time of 14CO2 disappearance, indicating one metabolic pool from which the observed 14CO2 production is derived. These results indicate that the glycine cleavage system is the predominant catabolic fate of glycine in the perfused rat liver and that production of 14CO2 from [1-14C]glycine is an effective monitor of metabolic flux through this system. Metabolic flux through the glycine cleavage system in the perfused rat liver was inhibited by processes which lead to reduction of the mitochondrial NAD(H) redox couple. Infusion of beta-hydroxybutyrate or octanoate inhibited 14CO2 production from [1-14C]glycine by 33 and 50%, respectively. Alternatively, infusion of acetoacetate stimulated glycine decarboxylation slightly and completely reversed the inhibition of 14CO2 production by octanoate. Metabolic conditions which are known to cause a large consumption of mitochondrial NADPH (e.g. ureogenesis from ammonia) stimulated glycine decarboxylation by the perfused rat liver. Infusion of pyruvate and ammonium chloride stimulated production of 14CO2 from [1-14C]glycine more than 2-fold. Lactate plus ammonium chloride was equally as effective in stimulating glycine decarboxylation by the perfused rat liver, while alanine plus ammonium chloride was ineffective in stimulating 14CO2 production.