The Effects of the Paleo Diet on Autoimmune Thyroid Disease: A Mixed Methods Review

The aim of this systematic review was to examine the characteristics of Paleolithic diet (PD) interventions designed for adult patients with autoimmune thyroid disease (AITD) in order to determine if diet elements have the potential to successfully reduce thyroid antibodies (Ab) such as thyroglobulin (Tg), thyroid peroxidase (TPO), and thyroid stimulating hormone receptor (TSHR), and improve thyroid hormones (thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH)) or resolve AITD pathogenesis. Randomized controlled trials (RCTs) with an adult population of 18 years and older, diagnosed with Hashimoto's thyroiditis (HT) or Graves' disease (GD) (Basedow's), who were placed on a diet of Paleolithic or ancestral nature, and achieved reduction of AITD Abs, improvement of thyroid hormones, and, or resolution of AITD were searched. Various electronic databases were used. Bias was assessed using critical appraisal tools from the Scottish Intercollegiate Guidelines Network (SIGN) and Joanna Briggs Institute (JBI). Studies were excluded according to exclusion criteria and results analyzed. One randomized controlled trial (RCT), a pilot study, and six case studies were found. In total, eight AITD studies focusing on Paleolithic or ancestral interventions were located. In highlight, females were the predominant gender. Case studies solely focused on AITD with protocols ranging from 8-60 weeks. All studies showed clinical improvements, one had significant improvement, two showed AITD resolution. After structured evaluation of nutritional interventions utilizing the PD on the effects of AITD, it was concluded foods of ancestral nature along with the addition of specific supplements, food components, exercise and mindfulness meditation, and exclusion of modern day foods have a considerable impact on thyroid Ab and hormones. The relevant studies suggest while this dietary protocol can be useful in clinical practice, larger-scale studies need to be conducted. Key teaching pointsThere are currently no dietary interventions recommended for the treatment of autoimmune thyroid disease. The Paleo diet has been documented to improve AITD antibodies and thyroid hormones in both Hashimoto's thyroiditis and Graves' disease.The Paleo diet can provide a natural source of nutrients similar to supplemental nutrients that have shown positive results on AITD.The paleo diet provides specific macronutrient percentages that may be beneficial in reducing AITD antibodies, while improving thyroid hormones.Methylation supplementation may be useful in AITD cases.

Preventing Potential Patient Harm Through Clinical Content Interventions During Oncology Clinical Trial Implementation

OBJECTIVES

Clinical trial documents are complex and may have inconsistencies, leading to potential site implementation errors and may compromise participant safety. This study characterizes the frequency and type of administrative and potential patient safety interventions (PPSIs) made during the review of oncology trial documents for clinical trial implementation by centralized clinical content specialists.

METHODS

A dedicated group of centralized clinical content specialists reviewed trial documents, including the protocol, laboratory manual, and pharmacy/cellular therapy manual, and collected intervention data over a 1-year period. Each trial was categorized by study phase and sponsor type, and multiple interventions could be identified per trial. Interventions were deemed administrative or PPSIs, with PPSIs further subcategorized as medication, laboratory, procedure related, or other.

RESULTS

Of 585 clinical trials reviewed, 269 (46%) required intervention(s). Among 1001 interventions, 171 (17.1%) were PPSIs. Most PPSIs were medication related (45.6%), with drug dosing interventions most frequently identified (53.8%). Phase 1 trials had the highest proportion of PPSIs (0.35:1) and administrative interventions (2:1) per trial compared with all other phases. Investigator-initiated trials saw the highest proportion of PPSIs per trial (0.44:1) of all sponsor types.

CONCLUSIONS

This study demonstrates a gap in patient safety when assessing trial documents for clinical trial implementation. One solution to address this gap is the utilization of a centralized team of clinical specialists to preemptively review trial documents, thereby enhancing patient safety during clinical trial conduct.

Inherited causes of exocrine pancreatic insufficiency in pediatric patients: clinical presentation and laboratory testing

Pediatric patients with exocrine pancreatic insufficiency (EPI) have symptoms that include abdominal pain, weight loss or poor weight gain, malnutrition, and steatorrhea. This condition can be present at birth or develop during childhood for certain genetic disorders. Cystic fibrosis (CF) is the most prevalent disorder in which patients are screened for EPI; other disorders also are associated with pancreatic dysfunction, such as hereditary pancreatitis, Pearson syndrome, and Shwachman-Diamond syndrome. Understanding the clinical presentation and proposed pathophysiology of the pancreatic dysfunction of these disorders aids in diagnosis and treatment. Testing pancreatic function is challenging. Directly testing aspirates produced from the pancreas after stimulation is considered the gold standard, but the procedures are not standardized or widely available. Instead, indirect tests are often used in diagnosis and monitoring. Although indirect tests are more widely available and easier to perform, they have inherent limitations due to a lack of sensitivity and/or specificity for EPI.

Measurement of Urinary Free Cortisol and Cortisone by LC-MS/MS

Monitoring urinary free cortisol (UFC) excretion helps assess adrenal function and is used to screen for endogenous Cushing's syndrome caused by an adrenal or pituitary tumor. While serum cortisol levels fluctuate in response to time of day, stress, and concentrations of cortisol-binding globulin (CBG), a 24-h urine collection measures the cortisol produced over the entire day and does not suffer from as much variability as a serum measurement.We describe here a method of measurement of urinary free cortisol (UFC) and cortisone using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Urine samples, combined with stable isotope-labeled internal standards, are extracted by liquid-liquid extraction using ethyl acetate and hexane. An API 5500 mass spectrometer operated in positive atmospheric pressure chemical ionization (APCI) mode is used for detection.

Impact of Unconjugated estriol (uE3) assay interference on prenatal screening tests

BACKGROUND

Unconjugated estriol (uE3) is an important biomarker in second trimester prenatal screening. Previous studies from our laboratory identified rare interference in the Beckman uE3 assay due to anti-ALP antibodies, which could be mitigated with a scavenger or heat-inactivated ALP (hALP). In the current study, 160 de-identified patient samples previously submitted for the Quad screen with low uE3 multiples of the median (MoM ≤0.50) were investigated for potential interference.

METHODS

A reagent pack spiking strategy with hALP was employed to understand if the interference could be identified and mitigated in a scalable manner. The 160 samples were measured using uE3 lot #920861 previously known to be subject to interference, lot #920861 spiked with hALP, and the vendor reformulated lot #922579. Samples were suspected to have interference if the percent difference in uE3 measurements was >50%. Pseudo-risks were calculated using a test patient environment to understand the screening impact due to the change in uE3 result.

RESULTS

Seventeen of the 160 samples had uE3 results that were >50% different between the hALP spiked and non-spiked reagent pack. Both original lot #920861 with hALP and reformulated lot #922579 identified the same 17 patients as having interference in lot #920861. Analysis of screening risks using a test patient environment showed that assay interference could result in false positives for one trisomy 21 and three trisomy 18 post-test risk calculations.

CONCLUSION

Our experiment of reagent pack spiking with hALP produced similar uE3 results to a reformulated reagent designed to address potential interference, demonstrating that this is a feasible strategy to screen for interference in a scalable manner. The vendor-provided reformulation addressed anti-ALP interference and improved the performance of the screen.

Iatrogenic Cushing syndrome in 24-hour urine free cortisol measurement

Cushing syndrome (CS) is caused by an excess of glucocorticoids that results in a variety of symptoms such as central obesity, moon facies, hirsutism, and reddish-purple stretch marks. Cortisol is the most potent endogenous glucocorticoid, and measuring the total amount excreted in the urine over a 24-hour period is useful to screen for CS caused by a tumor. However, most cases of CS are believed to be caused by exogenous glucocorticoids, such as prednisone and prednisolone, which are administered for anti-inflammatory and immunosuppressive treatments. This is often referred to as iatrogenic (drug-related or exogenous) CS. We modified an LC-MS/MS method for urine free cortisol to detect the presence of prednisone and prednisolone in patient samples. We wanted to understand the potential prevalence of exogenous CS in our patient population.

Comparison of Next-Generation Assays for Fecal Calprotectin vs the PhiCal Assay

OBJECTIVES

To compare the PhiCal assay (CALPRO), the first US Food and Drug Administration-approved assay for fecal calprotectin, to 4 next-generation assays.

METHODS

Stool samples from 50 patients were selected, and relevant clinical information was collected. Comparisons were performed using the PhiCal, fCAL turbo (BÜHLMANN), LIAISON Calprotectin (DiaSorin), QUANTA Lite Calprotectin ELISA (Inova Diagnostics), and Calprotectin Chemiluminescence ELISA (ALPCO) assays.

RESULTS

All 4 assays had acceptable agreement with PhiCal when qualitatively categorizing results. Within the PhiCal reportable range of 16 to 1,250 μg/g, the DiaSorin, Inova Diagnostics, and ALPCO assays had Spearman correlation coefficients of 0.98, 0.97, and 0.95 and positive biases of 17%, 20%, and 15%, respectively. The BÜHLMANN assay ran approximately 2-fold higher than the PhiCal assay but had a correlation coefficient of 0.98, with similar result categorization.

CONCLUSIONS

Our results demonstrate good comparison between PhiCal and 4 next-generation assays. Laboratories performing fecal calprotectin assays may have compelling reasons to adopt next-generation fecal calprotectin testing, such as greater automation, a decreased number of replicates needed per test, and the use of stool-extraction devices. These benefits could decrease turnaround times and lower costs. Although the results of the assays correlated, they are not standardized. Laboratories adopting the newer assays will need to further investigate their performance through validation studies.

Comparative Pharmacokinetics and Local Tolerance of Tenofovir Alafenamide (TAF) From Subcutaneous Implant in Rabbits, Dogs, and Macaques

The administration of antiretrovirals (ARVs) for HIV pre-exposure prophylaxis (PrEP) is highly efficacious and may benefit from new long-acting (LA) drug delivery approaches. This paper describes a subcutaneous, reservoir-style implant for the LA delivery of tenofovir alafenamide (TAF) and documents the preclinical assessment of implant safety and pharmacokinetics (PK) in New Zealand White (NZW) rabbits (3 groups of n = 5), beagle dogs (2 groups of n = 6), and rhesus macaques (2 groups of n = 3). Placebo implants were placed in rabbits (n = 10) and dogs (n = 12). Implant parameters, including selection of the TAF form, choice of excipient, and PCL formulation were tuned to achieve targeted concentrations of the active anabolite of TAF, tenofovir diphosphate (TFV-DP), within peripheral blood mononuclear cells (PBMCs) and mucosal tissues relevant to HIV transmission. Sustained concentrations of TFV-DP in PBMCs over 100 fmol/10⁶ cells were achieved in all animal species indicating that the implants effectively delivered TAF for 3-6 months. Unlike placebo implants without TAF, all active implants resulted in local adverse events (AEs) proximal to the implant ranging in severity from mild to moderate and included dermal inflammation and necrosis across all species. Despite these AEs, the implant performed as designed and achieved a constant drug release profile, supporting the continued development of this drug delivery platform.

Hereditary pancreatitis in a young adult: Acute to chronic

This report investigates an unusual case of recurrent pancreatitis. A 22-year-old female was admitted to the emergency room for severe abdominal pain, nausea, and weight loss. She reported having these symptoms since she was a toddler. The clinician ordered fecal pancreatic elastase-1, fat-soluble vitamins, molecular studies, and imaging of the pancreas by computed tomography. The screening test result for fecal pancreatic elastase-1 revealed severe pancreatic exocrine insufficiency, and the concentrations of fat-soluble vitamins were also low. Imaging showed scattered calcifications in the pancreas. These findings supported a diagnosis of chronic pancreatitis. Due to the rarity of chronic pancreatitis in young adults, molecular studies were performed. The patient was found to be homozygous for a mutation in the SPINK1 gene, which is associated with hereditary pancreatitis. This case report discusses hereditary pancreatitis and highlights data on the utilization of fecal pancreatic elastase-1 to assess pancreatic exocrine insufficiency.

Stool Reducing Sugars and Stool pH Are Poor Screening Tests for Intestinal Disaccharidase Deficiencies in Children

BACKGROUND

Tests for stool reducing sugars and stool pH are ordered for children with osmotic diarrhea to screen for carbohydrate malabsorption.

METHODS

We compared the results of the two screening tests, stool reducing sugars and stool pH, with a more definitive result from an intestinal tissue disaccharidase activity assay ordered for pediatric patients (<18 years old). Overall, 159 patients had results for tissue disaccharidase and stool reducing sugars, but only 115 had additional results of stool pH. Forty-six of the 159 patients had mild, moderate, or severe disaccharidase deficiencies. The sensitivity and specificity of the screening tests were calculated for individual disaccharidase deficiencies. In addition, trends of abnormal tissue disaccharidase, stool reducing sugars, and stool pH results were examined in different age groups.

RESULTS

The sensitivities for stool reducing sugars and stool pH were 9% to 28% and specificities were 74% to 81% for individual disaccharidase deficiencies. Infants (0 years of age) had the highest percentage of abnormal results across all three tests; however, the positive predicative values were 54% and 50% for stool reducing sugars and stool pH, respectively.

CONCLUSIONS

The screening tests, stool reducing sugars and stool pH, had low sensitivity compared with results of measured tissue disaccharidase activity in pediatric patients. Infants had the highest percentage of abnormal results for all three tests, but the screening tests still performed poorly in that age group. This study suggests that stool reducing sugars and stool pH should not be used as screening tests for carbohydrate malabsorption due to disaccharidase deficiencies in pediatric patients.

Clinical and Analytical Verification of an Automated Fecal Calprotectin Immunoassay with Extraction Device

BACKGROUND

Fecal calprotectin (FC) is a screening test for intestinal inflammation, and often used by clinicians to help identify and monitor patients with inflammatory bowel disease (IBD). Improvements in FC assays include moving to more automated immunoassays compared to ELISAs and simple-to-use extraction devices compared to manual weighing for the extraction process.

METHODS

A method comparison was performed between the PhiCal ELISA and LIAISON immunoassay for 53 stool samples, and the screening results were compared to the gold standard endoscopy with biopsy results. Clinical accuracy was assessed by comparing the FC results from each assay to the presence or absence of inflammation determined from the biopsy report. The performance of the extraction device was compared to manually weighing. Additional studies were completed to verify the manufacturer's claims.

RESULTS

The FC results were compared to the biopsy results for detecting inflammation. PhiCal ELISA had a sensitivity of 86% and specificity of 100%, while the LIAISON immunoassay had a sensitivity of 97% with specificity of 94%. Therefore, the LIAISON immunoassay performed better than the PhiCal ELISA. The extraction device performed well compared to manual weighing if stool samples were <800 μg/g, within Bristol stool types 2-6, and did not contain a significant amount of undigested material, fibrous material, or mucus.

CONCLUSION

The LIAISON immunoassay with extraction device has acceptable performance for clinical use in measuring fecal calprotectin.

Circulating omega-7 fatty acids are differentially related to metabolic dysfunction and incident type II diabetes: The Multi-Ethnic Study of Atherosclerosis (MESA)

AIM

Determine whether plasma omega-7 vaccenic acid and palmitoleic acid levels are related to homeostasis model of insulin resistance scores and incident type II diabetes, and whether race/ethnicity modifies these associations.

METHODS

Plasma phospholipid fatty acids were measured by gas chromatography with flame-ionization detection in Multi-Ethnic Study of Atherosclerosis participants. Linear regression determined associations of vaccenic acid and palmitoleic acid with log-transformed homeostasis model of insulin resistance scores (n=5689), and Cox regression determined associations with incident type II diabetes (n=5413, 660 cases). Race-interactions were tested.

RESULTS

Adjusting for typical risk factors, higher levels of plasma vaccenic acid were found to be inversely associated with insulin resistance scores across all four race/ethnicities, and a significant race-interaction was observed between Hispanics and Caucasians (P for interaction=0.03). Vaccenic acid was related to 17%, 32%, and 39% lower risks of incident type II diabetes in Black, Hispanic, and Chinese American participants, respectively. Differences in associations between races were detected (P for interactions<0.05). By contrast, higher levels of plasma palmitoleic acid were related to greater insulin resistance scores in Blacks (P<0.001) and Hispanics (P<0.001); significant race-based differences between associations were detected (P for interactions<0.05). Palmitoleic acid was correspondingly related to a 21% greater risk of incident type II diabetes in Black individuals.

CONCLUSIONS

Results suggest that plasma vaccenic acid and palmitoleic acid are markers of metabolic health and dysfunction, respectively. Coupled with previous evidence and the significant race-interactions, our findings have implications for future studies of the race-based differences in omega-7 fatty acids and their regulation in the context of deteriorating metabolic health.

Are calprotectin and lactoferrin equivalent screening tests for inflammatory bowel disease?

BACKGROUND

Lactoferrin and calprotectin are frequently ordered stool tests used to screen patients for inflammatory bowel disease versus functional bowel disease. Current guidelines recommend using either one to screen for inflammation in the GI tract; however, little information is available on how these 2 assays compare and their use in different clinical specialties.

METHODS

We compared order patterns for lactoferrin and calprotectin using data from a large reference laboratory over a 10-y period (2009-2019). We also studied the concordance of lactoferrin and calprotectin in cases where both tests were ordered concurrently. Finally, we reviewed the records at a university hospital to determine which clinicians ordered each test and the indications associated with orders.

RESULTS

Orders for calprotectin are increasing relative to lactoferrin. The relative proportion of calprotectin orders have increased from 60% to nearly 90% over the past decade. Results for lactoferrin and calprotectin show concordance (90%). Calprotectin and lactoferrin are ordered by different clinical specialties for different indications. Calprotectin is most often ordered by gastroenterologists in the context of abdominal pain. Lactoferrin is most often ordered by primary care providers in the context of acute diarrhea.

CONCLUSION

Lactoferrin and calprotectin are not treated as equivalent tests by clinicians.

Can fecal calprotectin serve as a screen for necrotizing enterocolitis in infants?

BACKGROUND

Researchers are debating if fecal calprotectin results are useful for infant patients, especially in screening for necrotizing enterocolitis (NEC). Currently, none of the FDA-approved calprotectin assays provide a cut-off for infant patients. We retrospectively analyzed data from a reference laboratory and university hospital to investigate if a cut-off could be established for infant patients.

METHODS

Data from a national reference laboratory of 5144 test results for fecal calprotectin were analyzed for infant patients, and a cut-off was estimated based on the distribution of results. Additionally, a literature proposed cut-off of 226 μg/g was also considered. Validation of either cut-off was attempted by review of the electronic medical record of our university hospital for 110 infant patients with results for fecal calprotectin.

RESULTS

Infants had a high percentage of elevated fecal calprotectin results when using the adult cut-offs set by the manufacturer. A cut-off of 247 μg/g was estimated based on the reference laboratory results for infants 0-2 months old, which is similar to a literature proposed cut-off of 226 μg/g. However, the positive predictive value (PPV) for both cut-offs was <0.6 when retrospectively analyzing data from a university hospital.

CONCLUSION

Due to the low PPVs, the two infant-specific cut-offs for fecal calprotectin would not be useful to screen for NEC in infants at our university hospital.

Bad Tests Die Slowly: The Myelin Basic Protein Example

BACKGROUND

Our national reference laboratory sought to improve stewardship for multiple sclerosis (MS) testing, which included orders for myelin basic protein (MBP) and oligoclonal bands (OCB). From 2011 to 2012, we performed 2 interventions for MS testing: one gentle-strength intervention of a publication designed to educate others about the lack of utility for MBP results and a second medium-strength intervention that included removal of MBP from the panel of MS tests. The ordering trends and practice variation were examined for OCB and MBP to retrospectively observe the effect of the interventions.

METHODS

Data from clients within academic and community hospitals were examined (n = 1710 clients). Ordering patterns for OCB and MBP were investigated from 2008 to 2018 by calculating the %OCB: %OCB = (OCB)/(OCB + MBP). Practice variation was examined by comparing the distribution of clients with different %OCB statistics before and after the interventions in 5-year blocks (2008-2012 vs 2014-2018).

RESULTS

From 2000 to 2011, the %OCB was approximately 50%, but gradually increased to 67% in 2018. For practice variation, analysis of the distribution of clients by %OCB also demonstrated a shift toward clients favoring OCB alone vs OCB + MBP for MS testing for the later time period of 2014-2018.

CONCLUSION

Our 2 interventions had a measurable, beneficial effect on ordering trends for MS testing over a 10-year period at a single reference laboratory. However, given that MBP has questionable clinical utility, stronger interventions are likely needed to bring about larger changes in ordering behavior.

End of the line for fetal lung maturity testing

OBJECTIVE

During the last decade, guidelines published by the American College of Obstetricians and Gynecologists (ACOG) and Society for Maternal Fetal Medicine (SMFM) have emphasized an increasingly limited role for fetal lung maturity (FLM) testing. As a reference laboratory for FLM testing, we were therefore interested in determining the impact of changing guidelines on our test volumes.

METHODS

We retrospectively reviewed FLM test volume data from 2006 to 2016 for the following FLM assays: lecithin/sphingomyelin ratio, phosphatidylglycerol, disaturated lecithin, and lamellar body count.

RESULTS

We found that there was a precipitous decline in test volumes from 2006 to 2016; our analysis led us to discontinue providing reference laboratory FLM testing in 2016 given the very low volumes.

CONCLUSIONS

The 2019 ACOG guidelines now state that FLM testing no longer has clinical utility. Therefore, clinical laboratory directors should meet with obstetrics providers to discuss discontinuation of FLM testing at their institutions.

High School Student Driving Perceptions Following Participation in a Distracted Driving Curriculum

Objectives. Distracted driving is a major public health issue in the United States. In response to requests from high school students participating in a university-based initiative, the authors describe the collaborative development and implementation of a curriculum designed to address distracted driving behaviors among students in four high-needs school districts in the northeastern United States. Method. The curriculum integrates current statistics on distracted and drowsy driving and three interactive learning stations: driving while distracted, walking while distracted, and driving while drowsy. Pre- and postsurveys were conducted to collect student driving data, assess student satisfaction with the program, and assess their likelihood of speaking up as a passenger in a high-risk situation. Results. The majority of students reported that they learned new information and would recommend the program to others. A Wilcoxon signed-rank test showed that students were more likely to speak up as a passenger with a distracted or drowsy driver (p < .001) after the program. Conclusion. This experience demonstrates a voluntary, multidisciplinary, university-based collaboration in the development of a novel public health education initiative. Based on the success of this phase, school districts elected to participate in Train the Trainer sessions to continue the program within their local high-needs school district.

A 43-year-old woman with unexplained elevation of hCG

OBJECTIVE

This case report investigates an unusual hCG result in a woman who is not pregnant.

PATIENT AND METHODS

A 43-year-old woman was admitted for recurrence of thrombotic thrombocytopenic purpura (TTP) and therapeutic plasma exchange (TPE) was initiated. Prior to transitioning the patient from TPE to immunosuppressive therapy, a serum qualitative hCG test was performed and was positive. Several etiologies for elevated hCG were considered and investigated, including heterophile antibody interference, endogenous hCG from pituitary or malignancy, and exogenous hCG.

RESULTS

Retrospective measurement of hCG levels in remnant samples, including a sample obtained prior to TPE initiation, demonstrated that the hCG elevation occurred with plasma administration for TPE. Further investigation with the American Red Cross confirmed that a plasma donor was unknowingly pregnant and in the latter half of the first trimester at the time of donation, when hCG levels peak.

CONCLUSION

In plasma recipients with unexplained hCG elevation, passive transfer of hCG from plasma should be considered in the differential diagnosis. Retrospective measurement of hCG in remnant samples obtained prior to plasma exchange can assist in confirming the source.

Steroids, steroid precursors, and neuroactive steroids in critically ill equine neonates

Hypothalamic-pituitary-adrenal axis (HPAA) dysfunction has been associated with sepsis and mortality in foals. Most studies have focused on cortisol, while other steroids have not been investigated. The objectives of this study were to characterise the adrenal steroid and steroid precursor response to disease and to determine their association with the HPAA response to illness, disease severity, and mortality in hospitalised foals. All foals (n=326) were classified by two scoring systems into three categories: based on the sepsis score (septic, sick non-septic [SNS] and healthy) and the foal survival score (Group 1: 3-18%; Group 2: 38-62%; Group 3: 82-97% likelihood of survival). Blood concentrations of adrenocorticotropic hormone (ACTH) and steroids were determined by immunoassays. ACTH-cortisol imbalance (ACI) was defined as a high ACTH/cortisol ratio. Septic foals had higher ACTH, cortisol, progesterone, 17α-OH-progesterone, pregnenolone, and androstenedione concentrations as well as higher ACTH/cortisol, ACTH/progesterone, ACTH/aldosterone, and ACTH/DHEAS ratios than SNS and healthy foals (P<0.01). Foals with DHEAS of 0.4-5.4ng/mL were more likely to have ACI (OR=2.5). Foals in Group 1 had higher ACTH, aldosterone, progesterone, and cortisol concentrations as well as ACTH/cortisol, ACTH/progesterone, and ACTH/DHEAS ratios than foals in Groups 2 and 3 (P<0.01). High progesterone concentrations were associated with non-survival and the cutoff value below which survival could be predicted was 23.5ng/mL, with 75% sensitivity and 72% specificity. In addition to cortisol, the response to the stress of illness in foals is characterised by the release of multiple adrenal steroids. DHEAS and progesterone were good predictors of HPAA dysfunction and outcome in hospitalised foals.

β-Arrestin-Biased Agonists of the GLP-1 Receptor from β-Amino Acid Residue Incorporation into GLP-1 Analogues

Activation of a G protein-coupled receptor (GPCR) causes recruitment of multiple intracellular proteins, each of which can activate distinct signaling pathways. This complexity has engendered interest in agonists that preferentially stimulate subsets among the natural signaling pathways ("biased agonists"). We have examined analogues of glucagon-like peptide-1 (GLP-1) containing β-amino acid residues in place of native α residues at selected sites and found that some analogues differ from GLP-1 in terms of their relative abilities to promote G protein activation (as monitored via cAMP production) versus β-arrestin recruitment (as monitored via BRET assays). The α → β replacements generally cause modest declines in stimulation of cAMP production and β-arrestin recruitment, but for some replacement sets cAMP production is more strongly affected than is β-arrestin recruitment. The central portion of GLP-1 appears to be critical for achieving bias toward β-arrestin recruitment. These results suggest that backbone modification via α → β residue replacement may be a versatile source of agonists with biased GLP-1R activation profiles.

A Designed Inhibitor of p53 Aggregation Rescues p53 Tumor Suppression in Ovarian Carcinomas

Half of all human cancers lose p53 function by missense mutations, with an unknown fraction of these containing p53 in a self-aggregated amyloid-like state. Here we show that a cell-penetrating peptide, ReACp53, designed to inhibit p53 amyloid formation, rescues p53 function in cancer cell lines and in organoids derived from high-grade serous ovarian carcinomas (HGSOC), an aggressive cancer characterized by ubiquitous p53 mutations. Rescued p53 behaves similarly to its wild-type counterpart in regulating target genes, reducing cell proliferation and increasing cell death. Intraperitoneal administration decreases tumor proliferation and shrinks xenografts in vivo. Our data show the effectiveness of targeting a specific aggregation defect of p53 and its potential applicability to HGSOCs.

Uncovering the Mechanism of Aggregation of Human Transthyretin

The tetrameric thyroxine transport protein transthyretin (TTR) forms amyloid fibrils upon dissociation and monomer unfolding. The aggregation of transthyretin has been reported as the cause of the life-threatening transthyretin amyloidosis. The standard treatment of familial cases of TTR amyloidosis has been liver transplantation. Although aggregation-preventing strategies involving ligands are known, understanding the mechanism of TTR aggregation can lead to additional inhibition approaches. Several models of TTR amyloid fibrils have been proposed, but the segments that drive aggregation of the protein have remained unknown. Here we identify β-strands F and H as necessary for TTR aggregation. Based on the crystal structures of these segments, we designed two non-natural peptide inhibitors that block aggregation. This work provides the first characterization of peptide inhibitors for TTR aggregation, establishing a novel therapeutic strategy.

Vasopressor use as a surrogate for post-intubation hemodynamic instability is associated with in-hospital and 90-day mortality: a retrospective cohort study

BACKGROUND

Evidence is lacking for what defines post-intubation hypotension in the intensive care unit (ICU). If a valid definition could be used, the potential exists to evaluate possible risk factors and thereby improve post-intubation. Thus, our objectives were to arrive at the best surrogate for post-intubation hypotension that accurately predicts both in-hospital and 90-day mortality in a population of ICU patients and to report mortality rates between the exposed and unexposed cohorts.

METHODS

We conducted a retrospective cohort study of emergent endotracheal intubations in a medical-surgical ICU from January 1, 2010 to December 31, 2011 to evaluate surrogates for post-intubation hypotension that would predict in-hospital and 90-day mortality followed by an analysis of exposed versus unexposed using our best surrogate. Patients were ≥18 years of age, underwent emergent intubation during their first ICU admission, and did not meet any of the surrogates 60 min pre-intubation.

RESULTS

The six surrogates evaluated 60 min post-intubation were those with any systolic blood pressures ≤90 mmHg, any mean arterial pressures ≤65 mmHg, reduction in median systolic blood pressures of ≥20%, any vasopressor administration, any non-sinus rhythm and, fluid administration of ≥30 ml/kg. A total of 147 patients were included. Of the six surrogates, only the administration of any vasopressor 60 min post-intubation remained significant for mortality. Twenty-nine patients were then labeled as hemodynamically unstable and compared to the 118 patients labeled as hemodynamically stable. After adjusting for confounders, the hemodynamically unstable group had a significantly higher in-hospital and 90-day mortality [OR (95% CI); 3.84 (1.31-11.57) (p value = 0.01) and 2.37 (1.18-4.61) (p-value = 0.02)].

CONCLUSIONS

Emergently intubated patients manifesting hemodynamic instability after but not before intubation, as measured by vasoactive administration 60 min post-intubation, have a higher association with in-hospital and 90-day mortality.

Structure of the toxic core of α-synuclein from invisible crystals

The protein α-synuclein is the main component of Lewy bodies, the neuron-associated aggregates seen in Parkinson disease and other neurodegenerative pathologies. An 11-residue segment, which we term NACore, appears to be responsible for amyloid formation and cytotoxicity of human α-synuclein. Here we describe crystals of NACore that have dimensions smaller than the wavelength of visible light and thus are invisible by optical microscopy. As the crystals are thousands of times too small for structure determination by synchrotron X-ray diffraction, we use micro-electron diffraction to determine the structure at atomic resolution. The 1.4 Å resolution structure demonstrates that this method can determine previously unknown protein structures and here yields, to our knowledge, the highest resolution achieved by any cryo-electron microscopy method to date. The structure exhibits protofibrils built of pairs of face-to-face β-sheets. X-ray fibre diffraction patterns show the similarity of NACore to toxic fibrils of full-length α-synuclein. The NACore structure, together with that of a second segment, inspires a model for most of the ordered portion of the toxic, full-length α-synuclein fibril, presenting opportunities for the design of inhibitors of α-synuclein fibrils.

A potent α/β-peptide analogue of GLP-1 with prolonged action in vivo

Glucagon-like peptide-1 (GLP-1) is a natural agonist for GLP-1R, a G protein-coupled receptor (GPCR) on the surface of pancreatic β cells. GLP-1R agoinsts are attractive for treatment of type 2 diabetes, but GLP-1 itself is rapidly degraded by peptidases in vivo. We describe a design strategy for retaining GLP-1-like activity while engendering prolonged activity in vivo, based on strategic replacement of native α residues with conformationally constrained β-amino acid residues. This backbone-modification approach may be useful for developing stabilized analogues of other peptide hormones.

α-Helix mimicry with α/β-peptides

We describe a general strategy for creating peptidic oligomers that have unnatural backbones but nevertheless adopt a conformation very similar to the α-helix. These oligomers contain both α- and β-amino acid residues (α/β-peptides). If the β content reaches 25-30% of the residue total, and the β residues are evenly distributed along the backbone, then substantial resistance to proteolytic degradation is often observed. These α/β-peptides can mimic the informational properties of α-helices involved in protein-protein recognition events, as documented in numerous crystal structures. Thus, these unnatural oligomers can be a source of antagonists of undesirable protein-protein interactions that are mediated by natural α-helices, or agonists of receptors for which the natural polypeptide ligands are α-helical. Successes include mimicry of BH3 domains found in proapoptotic proteins, which leads to ligands for antiapoptotic Bcl-2 family proteins, and mimicry of the gp41 CHR domain, which leads to inhibition of HIV infection in cell-based assays.

The history of behavior analysis: Some historiography and a bibliography

This article has two main purposes. First, it introduces the discipline of historiography and, second, it provides a selected bibliography on the history of behavior analysis. In introducing the former in the context of the latter, four important methodological considerations involved in the process and product of historiography are described: The sources from which historical materials are drawn (i.e., primary, secondary, and tertiary) and three dimensions along which historiography is conducted and evaluated-internalist vs. externalist, great person vs. Zeitgeist, and presentist vs. historicist. Integrated throughout are four purposes for the historiography of behavior analysis, as well as an overview of the topics covered in the extant literature. The manuscript concludes with a listing of current bibliographic material by publication type and topic.

Enhancement of α-helix mimicry by an α/β-peptide foldamer via incorporation of a dense ionic side-chain array

We report a new method for preorganization of α/β-peptide helices, based on the use of a dense array of acidic and basic side chains. Previously we have used cyclically constrained β residues to promote α/β-peptide helicity; here we show that an engineered ion pair array can be comparably effective, as indicated by mimicry of the CHR domain of HIV protein gp41. The new design is effective in biochemical and cell-based infectivity assays; however, the resulting α/β-peptide is susceptible to proteolysis. This susceptibility was addressed via introduction of a few cyclic β residues near the cleavage site, to produce the most stable, effective α/β-peptide gp41 CHR analogue identified. Crystal structures of an α- and α/β-peptide (each involved in a gp41-mimetic helix bundle) that contain the dense acid/base residue array manifest disorder in the ionic side chains, but there is little side-chain disorder in analogous α- and α/β-peptide structures with a sparser ionic side-chain array. These observations suggest that dense arrays of complementary acidic and basic residues can provide conformational stabilization via Coulombic attractions that do not require entropically costly ordering of side chains.

Broad distribution of energetically important contacts across an extended protein interface

Infection of cells by HIV depends upon profound structural rearrangements within the trimeric viral protein gp41. Critical to this process is the formation of a six-helix bundle in which a set of three N-terminal heptad repeat (NHR) helices assemble to form a core displaying long grooves that provide docking sites for three C-terminal heptad repeat (CHR) helices. We report experiments designed to discriminate between two alternative hypotheses regarding the source of affinity between individual CHR helices and the complementary groove: (1) affinity is dominated by interactions of a small cluster of side chains at one end of the CHR helix; or (2) affinity depends upon interactions distributed across the long CHR helix. We have employed two complementary experimental designs, and results from both favor the latter hypothesis.

Effect of a brief educational intervention on the attitudes of young women toward the intrauterine device

STUDY OBJECTIVE

The intrauterine device (IUD) is underused by young women, who are at high risk for unintended pregnancy. We aimed to assess the impact of a brief educational intervention on the attitudes of young women toward intrauterine contraception and to assess characteristics associated with a change in attitude.

DESIGN, SETTING, AND PARTICIPANTS

This is a planned secondary analysis of a survey of 144 women, aged 14-24 years, which assessed attitudes toward the IUD.

INTERVENTION

The analysis was planned to fully examine the impact of a 3-minute educational intervention about the IUD given during administration of the survey, which included risks and benefits of IUD use, costs, side effects, and a demonstration of the IUD insertion and removal process.

MAIN OUTCOME MEASURE

Proportions of participants with a positive attitude toward the IUD before and after the intervention were compared using McNemar's chi-square test for paired proportions. Factors associated with a change in attitude toward the IUD were evaluated using multivariable analysis.

RESULTS

Before the educational intervention, 14.7% (21/143) had both heard of the IUD and expressed a positive attitude toward it. After the intervention, this proportion increased to 53.8% (77/143) (P < .01). The increase in proportion with a positive attitude was consistent for all subpopulations. In multivariable analysis, the only significant predictor of a positive change in attitude toward the IUD was a history of voluntary sexual activity (adjusted odds ratio 10.3, 95% confidence interval 2.0-53.1).

CONCLUSIONS

A brief educational intervention significantly improves the attitude of young sexually active women toward the IUD.

Adolescent and young adult women's knowledge of and attitudes toward the intrauterine device

BACKGROUND

This study aimed to assess adolescent (aged 14-18 years) and young adult (aged 19-24 years) women's knowledge of and attitudes toward intrauterine devices (IUDs) before and after a brief educational intervention.

STUDY DESIGN

We administered a 43-item survey to 144 women aged 14-24 years, with half in each age category. The survey assessed knowledge of and attitudes toward IUDs, and incorporated a 3-min educational intervention about IUDs. Predictors for knowledge of and attitudes toward the IUD were examined using logistic regression.

RESULTS

Forty percent of participants had heard of the IUD. Having ever heard of the IUD was associated with age >18 years [adjusted odds ratio (OR)=5.7; 95% confidence interval (95% CI)=2.1-15.7], a higher level of maternal education (adjusted OR=4.5; 95% CI=1.5-13.3) and a history of voluntary sexual intercourse (adjusted OR=4.9; 95% CI=1.0-23.5). Of those who had heard of the IUD previously, 37.5% reported a positive attitude toward the IUD before the intervention. After the educational intervention, 53.5% of all participants reported a positive attitude toward the IUD, with both adolescent and young adult women having similarly positive attitudes (51.4% vs. 55.6%, p=.62). This positive attitude was associated only with a history of voluntary sexual intercourse (adjusted OR=5.2; 95% CI=1.3-21.1). The characteristics of the IUD that the participants strongly liked and disliked were rated similarly by the two age groups. However, more adolescent women considered the privacy of the IUD and the ability to use the copper IUD for 10 years as positive characteristics.

CONCLUSION

Most young women were unaware of IUDs but were likely to think positively about IUDs after being educated about them. Demographic and reproductive health history did not predict attitude; thus, all young women should be offered education about IUDs.

Residency education, preventive medicine, and population health care improvement: the Dartmouth-Hitchcock Leadership Preventive Medicine approach

In 2003, Dartmouth-Hitchcock Medical Center (DHMC) inaugurated its Leadership Preventive Medicine residency (DHLPMR), which combines two years of leadership preventive medicine (LPM) training with another DHMC residency. The aim of DHLPMR is to attract and develop physicians who seek to become capable of leading change and improvement of the systems where people and health care meet. The capabilities learned by residents are (1) leadership -- including design and redesign -- of small systems in health care, (2) measurement of illness burden in individuals and populations, (3) measurement of the outcomes of health service interventions, (4) leadership of change for improvement of quality, value, and safety of health care of individuals and populations, and (5) reflection on personal professional practice enabling personal and professional development. The DHLPMR program includes completion of an MPH degree at The Dartmouth Institute for Health Policy and Clinical Practice (formerly the Center for Evaluative Clinical Sciences) and a practicum during which the resident leads change to improve health care for a defined population of patients. Residents also complete a longitudinal public health experience in a governmental public health agency. A coach in the resident's home clinical department helps the resident develop his or her practicum proposal, which must then be approved by a practicum review board (PRB). Twelve residents have graduated as of July 2007. Residents have combined anesthesia, family medicine, internal medicine, infectious disease, pain medicine, pathology, psychiatry, pulmonary and critical care medicine, surgery, gastroenterology, geriatric psychiatry, obstetrics-gynecology, and pediatrics with preventive medicine.

The role of illness uncertainty on coping with fibromyalgia symptoms

This study examined the role of illness uncertainty in pain coping among women with fibromyalgia (FM), a chronic pain condition of unknown origin. Fifty-one FM participants completed initial demographic and illness uncertainty questionnaires and underwent 10-12 weekly interviews regarding pain, coping difficulty, and coping efficacy. Main outcome measures included weekly levels of difficulty coping with FM symptoms and coping efficacy. Multilevel analyses indicated that pain elevations for those high in illness uncertainty predicted increases in coping difficulty. Furthermore, when participants had more difficulty coping, they reported lower levels of coping efficacy. Results were consistent with hypothesized effects. Illness uncertainty accompanied by episodic pain negatively influenced coping efficacy, an important resource in adaptation to FM.

Uncertainty of Illness Relationships with Mental Health and Coping Processes in Fibromyalgia Patients

Fibromyalgia syndrome (FMS) is a chronic musculoskeletal pain condition poorly understood in terms of etiology and treatment by both physicians and patients. This condition of "uncertainty of illness" was examined as a variable involved in the adjustment of FMS patients, relating it to their depression, anxiety, affect, and coping styles. Fifty-one community-residing FMS patients provided self-report information on subsets of adjustment variables. Both cross-sectional and more dynamic longitudinal analyses showed that illness uncertainty was significantly associated with anxiety, negative affect, and avoidant and passive coping. Its positive relationship with depression was eliminated when a control variable, pain helplessness, was included as a covariate. Longitudinally, illness uncertainty interacted with interpersonally stressful daily events in predicting reports of reduced positive affect, suggesting that illness uncertainty acts as a risk factor for affective disturbances during stressful times. Implications of these results for therapeutic interventions are discussed.

Positive affect as a source of resilience for women in chronic pain

A sample of 124 women with osteoarthritis or fibromyalgia, or both, completed initial assessments for demographic data, health status, and personality traits and 10-12 weekly interviews regarding pain, stress, negative affect, and positive affect. Multilevel modeling analyses indicated that weekly elevations of pain and stress predicted increases in negative affect. Both higher weekly positive affect as well as greater positive affect on average resulted in lower negative affect both directly and in interaction with pain and stress. Finally, increases in weekly negative affect and higher average negative affect related to greater levels of pain in subsequent weeks. In contrast, higher levels of overall positive affect predicted lower levels of pain in subsequent weeks.

Fibromyalgia: evidence for deficits in positive affect regulation

OBJECTIVE

Fibromyalgia (FMS) is characterized by chronic pain, high psychiatric comorbidity, and the absence of observable pathology. Our objective was to examine positive and negative affective indices, both at the trait and contextual levels, in FMS compared with a chronic pain control group, osteoarthritis (OA).

METHODS

The sample consisted of 126 female FMS (87) and OA (39) patients from the community. Participants answered a self-report questionnaire assessing demographic and personality variables and were interviewed regarding average pain, affect, anxiety, and depression. Participants were then interviewed weekly for up to 12 weeks regarding pain, affect, fatigue, perceived interpersonal stress (IS), and positive interpersonal events (PE).

RESULTS

FMS participants reported lower levels of positive affect (p < .01) and extraversion (p < .01) than OA participants. There were no significant differences between groups in negative affect, depression, anxiety, or neuroticism after controlling for age and average pain. At the weekly level, FMS participants reported lower levels of positive affect (p < .01), but not negative affect. Furthermore, during weeks of elevated IS, FMS participants evidenced steeper declines in positive affect than OA participants (p < .01).

CONCLUSIONS

Despite the predominance of literature focusing on psychologic disturbance in FMS, these analyses identified dysfunctional positive affect regulation as a key feature of FMS. FMS status was uniquely characterized by lower levels of positive affect, especially during stressful weeks. These findings challenge current conceptualizations of FMS and point to new directions for interventions that focus on improving positive affective resources, especially during times of stress.

Coping effectiveness training for men living with HIV: results from a randomized clinical trial testing a group-based intervention

OBJECTIVE

This randomized clinical trial was designed to compare the effects of a theory-based coping effectiveness training (CET) intervention with an active informational control (HIV-Info) condition and a waiting-list control (WLC) condition on psychological distress and positive mood in HIV-seropositive gay men.

MATERIALS AND METHODS

The authors recruited 149 self-identified gay or bisexual men who were 21 to 60 years of age, reported depressed mood, and had CD4 levels of 200 to 700 cells/mm(3). CET and HIV-Info participants attended 10 90-minute group sessions during the 3-month intervention phase and six maintenance sessions over the remainder of the year. Participants were assessed at baseline and at 3, 6, and 12 months. Data were collected 1992 to 1994, before the introduction of HAART. Analyses were based on the 128 participants who completed the 3-month assessment.

RESULTS

After the 3-month intervention phase, when compared with HIV-Info, CET participants showed significantly greater decreases in perceived stress and burnout, and regression analyses indicated that significant increases in coping self-efficacy mediated the improvements in perceived stress and burnout. Compared with WLC, CET participants also showed significantly greater decreases in anxiety, and regression analyses indicated that significant increases in positive states of mind mediated the improvements in anxiety. Significant treatment group differences for positive morale were maintained at 6 and 12 months. In addition, optimism continued to increase in the CET and HIV-Info treatment groups during the maintenance phase.

CONCLUSIONS

CET can be an effective strategy for managing psychological distress and improving positive psychological states in patients confronting chronic illness.

Palmitate potentiation of glucose-induced insulin release: a study using 2-bromopalmitate

The mechanisms whereby fatty acids (FA) potentiate glucose-induced insulin secretion from the pancreatic beta cell are incompletely understood. In this study, the effects of palmitate on insulin secretion were investigated in isolated rat islets. Palmitate did not initiate insulin secretion at nonstimulatory glucose concentrations, but markedly stimulated insulin release at concentrations of glucose > or = 5.6 mmol/L. At concentrations of palmitate > or =0.5 mmol/L, the important determinant of the potency of the FA was its unbound concentration. At total concentrations < or = 0.5 mmol/L, both the total and unbound concentrations appeared important. Surprisingly, 2-bromopalmitate did not affect palmitate oxidation, but significantly diminished palmitate esterification into cellular lipids. Neither methyl palmitate, which is not activated into a long-chain acyl-CoA ester, nor 2-bromopalmitate affected glucose-stimulated insulin release. Further, 2-bromopalmitate partly inhibited the potentiating effect of palmitate. These results support the concept that FA potentiation of insulin release is mediated by FA-derived signals generated in the esterification pathway.

Corn Silage Management: Effects of Hybrid, Maturity, Chop Length, and Mechanical Processing on Rate and Extent of Digestion

Five experiments were conducted to evaluate the effects of hybrid, chop length, maturity, and mechanical processing of corn silage on dry matter and nutrient disappearance in the rumen. Corn silage that had not been dried or ground was incubated in macro in situ bags (30 x 35 cm) for 8, 16, 24,48, and 96 h. Experiments la and 2 evaluated the effects of maturity and mechanical processing for two corn silage hybrids harvested at two theoretical lengths-of-cut. Experiments 3 through 5 evaluated the effects of chop length and mechanical processing for two corn silage hybrids harvested at two-thirds milkline. The hybrid with low neutral fiber (NDF) concentrations had greater dry matter and starch disappearance than the hybrid with high NDF concentrations. The effect of chop length on nutrient disappearance was variable across experiments 3 through 5. Processing improved dry matter disappearance in experiments la, 2 (two-thirds milkline and blackline), 3, 4, and 5 at the majority of ruminal incubation timepoints. Starch disappearance was greater for unprocessed corn silage in experiment la (hard dough and two-thirds milkline) and was greater for processed corn silage in experiments 2 and 5. However, there was no consistent trend in starch disappearance between processed and unprocessed corn silage in experiments 3 and 4. This can be partially explained by the high disappearance of starch (experiment 3, > or = 98% and experiment 4, > or = 94%) by 24 h of ruminal incubation. Minimal differences were detected in NDF disappearance between processed and unprocessed corn silage across maturities. In experiments 2 and 5, crude protein disappearance was improved due to processing at some incubation timepoints. Rate of dry matter, starch (one-third milkline and two-thirds milkline), and NDF disappearance tended to increase when corn silage was mechanically processed in experiment 2. Dry matter, starch, and crude protein disappearance tended to be greater for corn silage harvested at the early maturity (one-third milkline) in experiment 2 compared with advanced maturities (two-thirds milkline and blackline). Disappearance of NDF was greater at early maturities compared with advanced maturities in experiments 1a and 2. Rate of dry matter (hybrid 3845), starch, and NDF (hybrid 3845) disappearance tended to decrease as maturity advanced from one-third milkline to blackline in experiment 2. These results suggest that the macro in situ method can be used to evaluate nutrient disappearance in the rumen.

Social support, distress, and well-being in older men living with HIV infection

Older men with HIV infection/AIDS, having often lived with the condition longer, are more likely to confront the stress of managing more advanced HIV disease than their younger counterparts. Meanwhile, they also are more likely to have less social support and experience more distress than younger persons with HIV infection. The moderating effect of social support on health functioning and distress is unknown for persons with HIV infection, particularly those who are older. Study objectives were to assess whether the association between perceived health functioning and psychological distress and well-being is moderated (or influenced) by social support and age and if the impact of social support on distress and well-being is more pronounced for older than for younger men living with HIV infection/AIDS. In this cross-sectional study of HIV-positive adult men (n = 199) who have sex with men, participants completed self-report assessments of perceived health functioning, social support, and psychological distress and well-being. Measures of health functioning and overall social support were significantly associated with outcome measures of distress and positive affect (all p < .05). However, the main effect for social support was qualified by a significant age-by-social support interaction for both outcomes (beta = -.190, p < .01 for distress; beta = .172, p < .05 for positive affect), indicating that the impact of social support on decreasing distress and increasing well-being was more pronounced in older men. The relationships between perceived health functioning and distress and well-being were not moderated by social support or age. The influence of social support on negative and positive moods in this population of HIV-infected men who have sex with men was significantly greater among older than among younger participants. With an increasing number of older people with HIV infection/AIDS, special efforts to create effective and sustainable social support interventions may be particularly beneficial to older persons living with HIV infection.

Dose related association of impact activity and bone mineral density in pre-pubertal girls

Impact activity is an important contributor to bone accrual. Children engaging in such activity have been shown to have greater bone mineral density (BMD) than their peers. This cross-sectional study was designed to quantify the association between BMD and impact activity in pre-pubescent girls, specifically examining for a dose-dependent relationship. Fifty 7-11-year-old Caucasian female gymnasts were grouped by hours of gymnastics participation during a 6-month period: LOW, 1-8 hours/week (hrs/wk); HIGH, >8 hrs/wk. They were compared with 20 controls, with height, weight, age, and Tanner stage averages matched to the gymnasts. Total body, forearm, hip, lumbar spine BMD, and body composition were measured by dual energy X-ray absorptiometry (DXA). Strength was measured by one repetition maximum testing, calcium intake was quantified by questionnaire, and physical activity was measured by questionnaire and activity monitors. Total and regional BMD were greater in the HIGH group than the controls (P<0.05). Furthermore, both total and forearm BMD were greater in the HIGH group than in the LOW group, and greater in the LOW group than in the controls (P<0.05). Simple regression analysis between hrs/wk of gymnastics activity versus total and regional BMD (using maturation-adjusted Z scores) yielded a positive slope for each site. R2 was greatest for hip BMD (R2 = 0.25), and least for lumbar spine (R2 = 0.10) (P<0.0001). In conclusion, in this group of pre-pubescent girls, we observed a dose-dependent relationship between BMD and hrs/wk of impact activity; even moderate doses of impact activity were associated with increased BMD.

Corn silage management: effects of hybrid, chop length, and mechanical processing on digestion and energy content

Two experiments were conducted to evaluate the effects of chop length and mechanical processing of two hybrids of whole plant corn on digestion and energy content of the total mixed ration (TMR). The experimental designs in experiments 1 and 2 were 6 x 6 and 4 x 4 Latin squares, respectively. In the first experiment, Pioneer hybrid 3845 was harvested at three theoretical lengths of cut: 11.1, 27.8, and 39.7 mm. At each chop length, corn was harvested with and without mechanical processing using a John Deere 5830 harvester with an onboard kernel processor. In the second experiment, Pioneer hybrid Quanta was harvested at two theoretical lengths of cut: 27.8 and 39.7 mm, with and without mechanical processing. In both experiments, the increase in the theoretical length of cut of corn silage increased the average length of cut and tended to increase the percentage of particles greater than 19 mm and lower the percentage of particles between 8 and 19 mm. In experiment 1, apparent total tract dry matter, organic matter, and neutral detergent fiber (NDF) digestibilities were lower for cows fed diets containing corn silage harvested at a short chop length (11.1 mm) than for corn silage harvested at a long chop length (39.7 mm). The lower total tract digestibility of nutrients may have contributed to the lower TDN, metabolizable energy (percentage of digestible energy), and NEL concentration of diets containing the short chop length corn silage (experiment 1). In experiment 2, total tract starch digestibility was greater for cows fed medium chop (27.8 mm) corn silage diets, and total tract NDF digestibility was greater for cows fed long chop (39.7 mm) corn silage diets. The opposing effect of total tract starch and fiber digestibilities between chop lengths may have contributed to the lack of difference in energy content of the diets in experiment 2. The TDN and NEL concentrations of the processed corn silage diets were greater than the unprocessed corn silage diets in experiment 1. The increase in energy concentration for the processed corn silage diet was due to greater total tract digestibility of organic matter and ether extract. Total tract starch digestibility was greater, and total tract NDF digestibility was lower for cows fed processed corn silage diets than unprocessed corn silage diets in experiment 2. The opposing effect of total tract starch and fiber digestibilities between processed and unprocessed corn silage may have contributed to the lack of difference in energy content of the diets.

Corn silage management: effects of hybrid, maturity, inoculation, and mechanical processing on fermentation characteristics

Two experiments were conducted to evaluate the effects of hybrid, maturity, mechanical processing, and inoculation of corn silage on fermentation characteristics. In experiment 1, Pioneer hybrid 3845 corn silage was harvested at three maturities (hard dough, one-third milkline, two-thirds milkline). In experiment 2, Pioneer hybrids 3845 and Quanta were harvested at three maturities (one-third milkline, two-thirds milkline, and blackline). In both experiments, corn silage was harvested at each maturity with and without mechanical processing and with and without inoculation. In experiments 1 and 2, corn silage was harvested at a theoretical length-of-cut of 6.4 and 12.7 mm, respectively. Maturity at harvest tended to have a greater impact on silage fermentation characteristics of corn silage than mechanical processing and inoculation. In experiments 1 and 2, corn silage harvested at the earliest maturity tended to have decreased dry matter content and increased water-soluble carbohydrate concentrations during the ensiling process than corn silage harvested at advanced maturities. In experiment 2, pH levels were lower for corn silage harvested at the early maturity (one-third milkline) compared with advanced maturities (two-thirds milkline and blackline) by 57 d after ensiling. The difference in pH can be explained by the greater concentration of water-soluble carbohydrates at the early maturity (one-third ML) soon after ensiling (2, 3, 6 and 10 d after ensiling) compared with advanced maturities (two-thirds ML and BL). The increased water-soluble carbohydrate concentrations in the less mature corn silage provided nutrients for bacteria to grow and produce primarily lactic acid (6, 10, and 57 d after ensiling) and some acetic acid (2, 3, 6, and 10 d after ensiling) which reduced the pH of corn silage more than at the advanced maturities. There was a slight change in silage fermentation characteristics when corn silage was inoculated with Pioneer 1132 inoculant in experiment 1. The inoculated corn silage had increased temperature, lactate and acetate concentrations, and lower water-soluble carbohydrate and pH levels compared with uninoculated corn silage. Dry matter recovery tended to be greater for processed corn silage in experiment 1, and greater for unprocessed corn silage in experiment 2. It appears that when fermentation was greater (increased temperature and lactate concentration 57 d after ensiling) the dry matter recovery was lower.

Corn silage management III: effects of hybrid, maturity, and processing on nitrogen metabolism and ruminal fermentation

Two experiments were conducted to evaluate the effects of maturity and mechanical processing of two hybrids of whole plant corn silage on DM and OM digestibility, nitrogen metabolism, ruminal fermentation, and milk production and composition in lactating Holstein cows. In the first experiment, Pioneer hybrid 3845 whole plant corn was harvested at hard dough, one-third milkline, and two-thirds milkline with a theoretical length-of-cut of 6.4 mm. At each stage of maturity, corn was harvested with (1-mm roll clearance) and without (15.9-mm roll clearance) mechanical processing using a John Deere 5830 harvester with an on-board kernel processor. In the second experiment, Pioneer hybrids 3845 and Quanta were harvested at one-third milkline, two-thirds milkline, and blackline stages of maturity with and without mechanical processing. The theoretical length-of-cut was 12.7 mm. Total tract DM and OM digestibilities were lower for cows fed diets containing processed corn silage in experiment 1, and tended to be lower for cows fed diets containing unprocessed corn silage in experiment 2. Ruminal acetate concentrations were greater and ruminal propionate concentrations were lower 2 and 6 h after feeding for cows fed diets containing corn silage harvested at physiological maturity in experiment 2. This was due to decreased digestion of starch at advanced maturities in experiment 2. Ruminal pH tended to decline rapidly after feeding for cows fed hybrid Quanta (2 h) compared to hybrid 3845 (5 h) corn silage based diets. Ruminal acetate concentrations decreased and ruminal propionate concentrations increased 2 and 6 h after feeding for cows fed diets containing hybrid Quanta corn silage compared to hybrid 3845 corn silage. This was related to a greater starch concentration in the corn silage, greater starch intake, and increased rate of starch digestion for cows fed hybrid Quanta corn silage-based diets. Microbial nitrogen flow was lower and feed nitrogen flow was greater for cows fed diets containing hybrid Quanta corn silage. The lower microbial nitrogen flow was due to lower microbial nitrogen concentration and nonammonia nitrogen flow to the duodenum. Milk fat and protein concentrations had a strong quadratic relationship with forage NDF intake as a percentage of body weight. When forage NDF intake as a percentage of body weight dropped below 0.70%, there was a rapid decline in milk fat and protein concentrations.

Corn silage management II: effects of hybrid, maturity, and mechanical processing on digestion and energy content

Two experiments were conducted to evaluate the effects of maturity and mechanical processing of two hybrids of whole plant corn on starch, fiber, and ether extract digestibilities and energy content of the total mixed ration fed to lactating Holstein cows. In the first experiment, Pioneer hybrid 3845 whole plant corn was harvested at hard dough, one-third milkline, and two-thirds milkline with a theoretical length of cut of 6.4 mm. At each stage of maturity, corn was harvested with and without mechanical processing. In the second experiment, Pioneer hybrids 3845 and Quanta were harvested at one-third milkline, two-thirds milkline, and blackline stages of maturity with and without mechanical processing. The theoretical length of cut was 12.7 mm. The measured TDN and NEL concentrations were lower for diets containing processed corn silage in experiment 1 and greater for diets containing processed corn silage in experiment 2, compared with diets containing unprocessed corn silage. The lower energy content for diets containing processed corn silage in experiment 1 can be explained by the lower total tract NDF, ether extract, and CP digestibilities. The greater energy content for diets containing processed corn silage in experiment 2 can be attributed to greater total tract starch and NDF digestibilities for cows fed processed corn silage diets. In experiment 2, diets containing processed corn silage (1.59 Mcal/kg) had approximately 2.6% more energy available per kilogram of DM consumed compared with diets containing unprocessed corn silage (1.55 Mcal/kg). For hybrid Quanta in experiment 2, the TDN and NEL concentrations of diets containing corn silage harvested at two-thirds ML were greater than at other maturities.

Increasing triglyceride synthesis inhibits glucose-induced insulin secretion in isolated rat islets of langerhans: a study using adenoviral expression of diacylglycerol acyltransferase

The mechanisms by which prolonged exposure to elevated levels of fatty acids (FA) adversely affects pancreatic beta-cell function remain unclear. Studies in the Zucker diabetic fatty rat have suggested that excessive accumulation of triglycerides (TG) in islets plays a key role in the deleterious effects of FA. However, a direct relationship between TG accumulation and defective beta-cell function has not been established. The aim of the present study was therefore to determine whether increasing TG synthesis in isolated rat islets of Langerhans impairs insulin secretion. To this end, we infected isolated rat islets with an adenovirus encoding for the enzyme catalyzing the last step of triglyceride synthesis, acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT). DGAT overexpression did not modify glucose oxidation nor palmitate oxidation, but increased palmitate incorporation into triglycerides by approximately 2-fold. Islets overexpressing DGAT and cultured in elevated glucose levels for 72 h had markedly impaired insulin secretion in response to glucose, but responded normally to the nonglucose secretagogues glyburide and potassium chloride. The deleterious effects of DGAT overexpression were not additive to those of prolonged exposure to palmitate. We conclude that a selective increase in TG content impairs glucose-induced insulin secretion, a mechanism likely to mediate, at least in part, the deleterious effects of FA on pancreatic beta-cell function.

Implication of alpha4 phosphoprotein and the rapamycin-sensitive mammalian target-of-rapamycin pathway in prolactin receptor signalling

A prolactin (PRL)-responsive 3'-end cDNA encoding rat alpha4 phosphoprotein was previously isolated from a rat lymphoma cDNA library. Rat alpha4 is a homologue of yeast Tap42 and is a component of the mammalian target-of-rapamycin (mTOR) signalling pathway that stimulates translation initiation and G1 progression in response to nutrients and growth factors. In the present study, the full-length rat alpha4 cDNA was obtained by 5'-RACE and the 1023 bp open reading frame predicted a 340 amino acid protein of 39.1 kDa. The alpha4 mRNA was expressed in quiescent PRL-dependent Nb2 lymphoma cells deprived of PRL for up to 72 h but expression was downregulated within 4 h of PRL treatment. In contrast, PRL-independent Nb2-Sp cells showed constitutive expression of alpha4 that was not affected by PRL. Western analysis of Nb2 cell lysates or of V5-tagged-alpha4 expressed in COS-1 cells detected a single immunoreactive band of approximately 45 kDa. Enzymatic deglycosylation of affinity-purified 45 kDa alpha4 yielded the predicted 39 kDa protein. Phosphorylation of Nb2 alpha4 was induced by PRL or 2-O-tetradecanoyl-phorbol-13-acetate (TPA) and further enhanced by a combination of PRL and TPA. The Nb2 alpha4 associated with the catalytic subunit of protein phosphatase 2A and localized predominantly in Nb2 nuclear fractions with trace amounts in the cytosol. The immunosuppressant drug rapamycin inhibited proliferation of Nb2 cells in response to PRL or interleukin-2, but had no effect on Nb2-Sp cells. Furthermore, transient overexpression of alpha4 in COS-1 cells inhibited PRL stimulation of the immediate-early gene interferon regulatory factor-1 promoter activity. Therefore, PRL downregulation of alpha4 expression and/or PRL-inducible phosphorylation of alpha4 may be necessary for PRL receptor (PRLr) signalling to the interferon regulatory factor-1 promoter in the Nb2 cells and, furthermore, implicates cross-talk between the mTOR and PRLr signalling cascades during Nb2 cell mitogenesis.