Perspectives of clinicians and patients on community-based maintenance care for adults with obesity

Background

Tertiary metabolic health services are in high demand as people with severe obesity increase. Once predetermined health goals have been achieved patients must transition to community-based care to urgently free up capacity in tertiary services. Maintenance of successful outcomes achieved via tertiary services is therefore important to limit rates of relapse back to these services.

Methods

This qualitative project explored community-based care needs to help individuals living with obesity maintain health gains. An interview schedule guided one-on-one interviews with patients and staff from metabolic clinics in Sydney, Australia.

Results

We interviewed 22 patients and 13 clinicians. A lack of appropriate and consistent clinical support in the community was identified by patients and clinicians. Most clinicians agreed primary care was key to successful maintenance care. Lack of primary care understanding of appropriate management and support for patients with obesity, lack of bariatric equipment and limited funding for allied health were all seen barriers to appropriate support beyond their clinics. Patients were highly reluctant to transition from tertiary clinics and reluctant to engage with community-based care due to experience of limited clinical/social support and bariatric equipment, demeaning clinical interactions, lack of care coordination and being stigmatised. Support groups outside of the clinic were also identified important in mitigating social isolation and stigma. Both patients and clinicians felt support groups have potential to provide important supplementary help to individuals with obesity outside tertiary settings.

Conclusions

Currently, individuals aiming to maintain their weight are likely to struggle in the context of existing community care provisions. Integrated, community-based and affordable models of care are needed now to allow tertiary metabolic services discharge their patients safely.

Key messages

• Tertiary obesity services are at capacity.

• Subsequent community care for people wth obesity needs to be mote appropriate tp promote weight maintenance.

Impact of BMI on breast screening participation: a data linkage study

Background

Regular mammographic screening can reduce breast cancer morbidity and mortality. Participation rates are suboptimal in Australia’s fully funded biennial breastscreening program (BreastScreen) for women aged 50-74. Despite obesity being a well-established risk factor for post-menopausal breast cancer, cross sectional data suggests obesity may be a risk factor for non-participation in recommended screening, due to adverse screening experiences. This research aimed to ascertain the link obesity and non-participation by using data linkage of routinely collected data.

Methods

Data for women age eligible for breast screening were linked between the NSW Cancer Registry and the Australian Longitudinal Study of Women’s Health (ALSWH) to create a cohort of women who either participated in screening as recommended or not. Women from the 1946-1951 ALSWH birth cohort were included in the study. These women reported BMI via 8 survey waves. The primary outcome was adherence to breast screening measured by frequency of screening over the follow-up period (1998-2016). Unadjusted risk ratios were calculated using mixed-effects logistic regression for the association between BMI and screening participation.

Results

The study included 2804 linked records of age eligible women (mean age of 52.37[SD 5.47]). 22.8% of the cohort were obese (BMI>30kg/m2). Obesity was significantly associated with non-recommended screening participation (screening within 3 years of last breast screen); odds ratio 1.63 (95% confidence interval 1.32 to 2.00, p < 0.0001).

Conclusions

Obesity has a significantly impact on recommended participation in a nationally provided breast screening program, despite obesity being a risk factor for post- menopausal breast cancer. Optimising participation among higher risk and under-screened women in under utilised breast cancer screening programs is warranted. Development of targeted interventions to increase screening participation among these higher risk women is needed.

Key messages

• Women living with obesity and less likely to participate in recommended breast screening.

• Targeted interventions are needed to optimise participation in breast screening to ensure these higher risk women are not at higher risk of adverse outcomes due to breast cancer.

Abstract PR002: Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS)

Background: We evaluated the activity of neoadjuvant ICB in localized resectable DDLPS (n=17) and undifferentiated pleomorphic sarcomas (UPS; n=10). DDLPS and UPS patients were randomized to neoadjuvant nivolumab or ipilimumab+nivolumab, with UPS patients receiving concurrent radiotherapy. We assessed genomic markers of early relapse (progression before surgery or relapse within 52 weeks following surgery) using longitudinally acquired tumor samples. Methods: RNA sequencing (RNAseq) and whole genome sequencing (WGS) were performed on longitudinally acquired samples (baseline biopsies and surgical specimens). Differential gene expression between any two groups of patients (i.e., non-early relapse [non-relapsers] vs early relapse [relapsers]) were selected (fold change>1.5 and p value<0.05). Gene set enrichment analyses (GSEA) of KEGG pathways were performed and a network-based approach used to identify genes/pathways associated with MHC-I. Results: At a median follow-up of 23 months, 12 patients (9 DDLPS, 3 UPS) relapsed, including 7 early relapses (relapsers: 5 DDLPS, 2 UPS). The median relapse-free survival was 22 months in DDLPS patients (6 months in relapsers; not reached [NR] in non-relapsers) and NR in UPS patients. At baseline, the most differentially upregulated pathways in non-relapsers compared to relapsers were “graft versus host disease” (GSEA Normalized Enrichment Score[NES]=2.25; False Discovery Rate[FDR] q= 0.009), “natural killer cell mediated cytotoxicity” (NES=2.17; FDR q=0.009), “antigen processing and presentation” (NES=2.16; FDR q=0.009), “allograft rejection” (NES=1.99; FDR q=0.019) and “B-cell receptor signaling pathway” (NES=1.87; FDR q=0.018). In DDLPS patients, the antigen presentation and processing pathway was the most upregulated pathway in non-relapsers compared to relapsers (NES=2.01; FDR q=0.025) while it was not significantly upregulated in UPS (NES=1.15; FDR q=0.62). When looking at pathways longitudinally, the antigen presentation and processing pathway was significantly upregulated at surgery compared to baseline in DDLPS. As antigen presentation and processing was significantly upregulated in DDLPS patients and associated with relapse, we looked for expressed neoantigens that may be processed and presented. Using WGS, we detected 5712 rearrangements at baseline in DDLPS, of which 230 were found in more than one tumor specimen. We also sought to identify genes associated with MHC-I. We selected genes upregulated during ICB comparing baseline to surgical specimens in DDLPS relapsers and looked at the top 10% of genes associated with MHC-I in order to identify potential therapeutic targets for combination. We identified 41 genes upregulated during ICB and associated with MHC-I in relapsers, for which up to 275 inhibitory compounds were found in drug databases. Conclusion: Antigen presentation and processing is a major driver of response to immunotherapy. Future efforts should focus on identifying which antigens are presented to find synergizing compounds in order to increase the clinical benefit of ICB.

Citation Format: Elise F. Nassif, Chia-Chin Wu, Kadir Akdemir, Russell G. Witt, Raymond Traweek, Brandon Cope, Prapassorn Thirasastr, Taylor Tate, Grace Mathew, Shadarra Crosby, Randy Chu, Mohammad Mohammad, Kenna Shaw, Ingram Davis, Khalida Wani, Alexander J. Lazar, Wei-Lien Wang, Sheila Duncan, Ashleigh B. Guadagnolo, Andrew J. Bishop, Valerae Lewis, Justin E. Bird, Keila E. Torres, Kelly K. Hunt, Barry W. Feig, Christopher P. Scally, Ravin Ratan, Shreyaskumar Patel, Robert S. Benjamin, Robert Satcher, Kevin McBride, Wolf H. Fridman, Ignacio Wistuba, Andrew Futreal, Jennifer A. Wargo, Neeta Somaiah, Christina L. Roland, Emily Z. Keung. Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS) [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr PR002.

Randomized phase II study of neoadjuvant checkpoint blockade for surgically resectable undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS): Survival results after 2 years of follow-up and intratumoral B-cell receptor (BCR) correlates

LBA11501

Background: We conducted a randomized, phase II non-comparative trial evaluating the efficacy of neoadjuvant ICB [nivolumab or ipilimumab/nivolumab] in patients (pts) with surgically resectable retroperitoneal DDLPS or extremity/truncal UPS treated with concurrent neoadjuvant radiation therapy (XRT, UPS only). Methods: As of February 28 2022, all pts have a minimum follow-up of 2 years from the start of ICB treatment. Progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan Meier method. The association of pathologic response (percent hyalinization and viable tumor at surgery) with PFS and OS was assessed using Cox univariate models. Comparison of survival curves was done by log-rank method. The intratumoral BCR repertoire was evaluated by bulk tumor RNA sequencing with TRUST4 algorithm, on biopsy specimens collected at baseline. Description of the intratumoral BCR repertoire included diversity by inverse Simpson index, and clonal distribution by Gini coefficient. High and low categories were defined by median values. Results: At a median follow-up of 31 months (interquartile range [IQR]=27-43) since start of ICB treatment, the median PFS was not reached (NR) in UPS (IQR=19-NR) and 18 months for DDLPS (IQR=8-NR), with 13 pts experiencing relapse (2 UPS, 11 DDLPS) and 2 pts who had progressive metastatic disease on treatment (1 UPS, 1 DDLPS). Five pts died of disease relapse (1 UPS, 4 DDLPS) and the median OS was NR. There was no association between percent hyalinization at surgery and PFS (Hazard Ratio [HR]=0.98, p=0.12) or OS (HR=0.99, p=0.60) nor between percent viable tumor at surgery and PFS (HR=1.00, p=0.62) or OS (HR=1.00, p=0.67). There was no association between RECIST response and PFS (p=0.67) or OS (p=0.67). The median BCR heavy chain (IgH) clonal counts detected at baseline was 2,536 per sample (IQR=82-7,680), and the median BCR light chain (IgL) clonal count was 8,870 per sample (IQR=306-30,214). Pts with higher intratumoral BCR clonality and diversity at baseline tended to have longer PFS (Table). High BCR IgH clonality was significantly associated with OS (p=0.02) with consistent trends in each histotype (DDLPS: p=0.06; UPS: p=0.25). Conclusions: Survival results demonstrate efficacy of ICB with XRT in UPS but there is a crucial need to define better predictive markers of survival after neoadjuvant therapy. Further characterization of the BCR repertoire is ongoing and will be presented at the meeting. Clinical trial information: NCT03307616. [Table: see text]

Identifying gut microbial signatures associated with B cells and tertiary lymphoid structures (TLS) in the tumor microenvironment (TME) in response to immune checkpoint blockade (ICB)

2511

Background: While ICB has significantly improved clinical outcomes across several cancer types, only 15-20% of patients develop a durable response. Thus, novel and targetable biomarkers are needed. There is increased appreciation of the role of the gut microbiome, and TLS and B-cells in the TME in response to ICB. Here, we investigate the association between these two determinants of response in patient specimens from three randomized phase 2 neoadjuvant ICB trials of nivolumab +/- ipilimumab (melanoma (MEL; NCT02519322; n=23), non-small-cell lung cancer (NSCLC; NCT03158129; n=31), sarcoma (SARC; NCT02301039; n=17). Methods: Patients were categorized as responders (R) or non-responders (NR) based on major pathologic response, as defined in each histotype (MEL and NSCLC viable tumor ≤10%; SARC hyalinization>30%). Baseline fecal samples were profiled via 16S rRNA gene sequencing from all three cohorts to assess the composition of patient gut microbiomes. Transcriptional profiles of biopsies collected pre-ICB for MEL and SARC, and post-ICB for MEL, SARC, and NSCLC were used to assess TLS (CXCL13, CCL18, CCL19, CCL21) and B-cell (PAX5, CD79B, CR2, MS4A1) signatures in the TME, by calculated mean values of normalized gene expressions. Comparison between samples were carried out using the Wilcoxon signed-rank test. Results: There were 21 R overall (NSCLC n=9; MEL n=9; SARC n=3). Despite significant differences in alpha and beta diversity across cohorts, relative abundance of Ruminococcus was significantly higher in R (p=0.003; NSCLC p<0.001; MEL p=0.049; SARC p=0.7). B-cell signature was significantly higher post-ICB in R (R vs NR, post, TLS p=0.13; B-cell p=0.003), with consistent trends in each cohort. Longitudinal evaluation of transcriptional profiles showed that expression of TLS and B-cell signatures increased with treatment in R (pre vs post, MEL and SARC; TLS p=0.0098; B-cell p<0.001) but not NR (pre vs post; TLS p= 0.87; B-cell p= 0.15), with consistent trends in sarcoma and melanoma subgroups. Combined correlative analysis with matched specimen showed that patients with higher pre-ICB relative abundance of Ruminococcus (above median) had significant increase in B-cell signatures (pre vs post, MEL and SARC; TLS p=0.052; B-cell p=0.002) which was not seen in patients with low abundance (below median) of Ruminococcus (pre vs post, MEL and SARC; TLS p=0.56; B-cell p=0.69). Conclusions: Unifying signatures in the gut microbiome are associated with response to ICB and increased B-cell infiltration and TLS formation in the TME. We expect these findings to energize mechanistic studies and new microbiome-based interventional approaches to improve clinical outcomes with ICB. Clinical trial information: NCT02519322, NCT03158129, NCT02301039.

Unusual Near-Horizon Cosmic-Ray-like Events Observed by ANITA-IV

ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0.27} anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous noninverted polarity, a p=5.3×10^{-4} chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply upcoming anomalous events similar to the two such events seen in prior flights.

Targeting MYC: From understanding its biology to drug discovery

The MYC oncogene is considered to be a high priority target for clinical intervention in cancer patients due to its aberrant activation in more than 50% of human cancers. Direct small molecule inhibition of MYC has traditionally been hampered by its intrinsically disordered nature and lack of both binding site and enzymatic activity. In recent years, however, a number of strategies for indirectly targeting MYC have emerged, guided by the advent of protein structural information and the growing set of computational tools that can be used to accelerate the hit to lead process in medicinal chemistry. In this review, we provide an overview of small molecules developed for clinical applications of these strategies, which include stabilization of the MYC guanine quadruplex, inhibition of BET factor BRD4, and disruption of the MYC:MAX heterodimer. The recent identification of novel targets for indirect MYC inhibition at the protein level is also discussed.

Transformation of remnant algal biomass to 5-HMF and levulinic acid: influence of a biphasic solvent system

The primary commercial product from the green microalgae Dunaliella salina is β-carotene. After extracting the lipophilic fraction containing this red-orange pigment, an algal residue remains. As the carotenogenesis is induced by light stress with simultaneous nitrogen depletion, the protein content is low and the remnant is comprised largely of storage carbohydrates. In this work, we transformed the defatted remnant directly to the platform chemicals, 5-hydroxy methyl furfural (5-HMF) and levulinic acid (LA), without previous purification or any pretreatment. The batch experiments were carried out in an autoclave under biphasic solvent conditions at 453 K for 1 h using acidic ZSM-5 zeolite as a heterogeneous catalyst. Mixtures of methyl isobutyl ketone (MIBK/H₂O) or tetrahydrofuran (THF/H₂O/NaCl) with water were used to create the biphasic reactor conditions. The biphasic reaction mixtures helped to increase the 5-HMF yield and simultaneously mitigated the formation of insoluble humins. The carbon yields of 5-HMF and of LA in the MIBK/H₂O biphasic system without NaCl were 13.9% and 3.7%, respectively. The highest carbon yield of 5-HMF (34.4%) was achieved by adding NaCl to the reaction mixture containing THF/H₂O. The experimentally measured partition ratios of 5-HMF between the two liquid phases were compared to the predictions calculated by the computational method COSMO-RS, which is a quantum chemistry-based method to predict the thermodynamic equilibria of liquid mixtures and the solubilities. The COSMO-RS predicted partition ratios of 5-HMF were in line with the experimentally measured ones.

Defatted algal remnant is transformed to 5-HMF and LA.

Evaluation of La1−xSrxMnO3 (0 ≤ x < 0.4) synthesised via a modified sol–gel method as mediators for magnetic fluid hyperthermia

A range of lanthanum strontium manganates (La_1−xSr_xMnO₃) where 0 ≤ x ≤ 0.4 were prepared using a modified peroxide sol–gel synthesis. The crystal structure of these materials was investigated and their potential as mediators for magnetic fluid hyperthermia was evaluated.

Clinical management patterns and treatment outcomes in patients with non-small cell lung cancer (NSCLC) across Europe: EPICLIN-Lung study

BACKGROUND

Throughout Europe, physicians face similar challenges in non-small cell lung cancer (NSCLC) management, but comprehensive international information on usual clinical practice is lacking so the burden of NSCLC is not fully understood.

METHODS

This multinational, multicentre, non-interventional study (NCT00831909) was conducted in eight European countries. Patients with confirmed NSCLC were consecutively enrolled from January to March 2009 and followed for 12 months or until death. Information was collected on patient and disease characteristics, diagnosis and treatment patterns, and clinical outcomes. Spontaneously reported adverse events (AEs) were also recorded.

RESULTS

Data were available for 3508 patients. Most patients (77.5%) were male, median (range) age was 65.0 years (21.6-90.7), the majority of patients had a World Health Organization performance status of ≤1 (74.7%), and 10.8% were never smokers. The most prevalent histologies were adenocarcinoma (43.8%) and squamous-cell carcinoma (29.4%). Most patients presented with advanced disease (11.6% with stage IIIA, 18.7% with stage IIIB, 48.6% with stage IV). In stage IV disease, median progression-free survival and overall survival (months) by first-line treatment cluster were platinum regimens: 6.5, 10.8; non-platinum regimens: 4.3, 8.5; regimens with bevacizumab 8.7, 12.9; investigational regimens: 5.6, 10.8; best supportive care: 5.4, 6.6. The most frequently reported severe (Common Terminology Criteria for Adverse Events v3.0>2) AEs were blood/bone marrow (16.0%) and pulmonary/upper respiratory (7.8%). Key limitations of this study related to its non-interventional nature and wide regional focus; for example, achieving a representative sample of the overall NSCLC population, variation in recruitment between countries, and data based on information from medical records derived from routine visits.

CONCLUSIONS

The Epidemiological Study to Describe NSCLC Clinical Management Pattern in Europe-Lung (EPICLIN-Lung) study provides new insights into the descriptive patterns and clinical management strategies for NSCLC across Europe, and how they affect patient outcomes.

IgM memory B cells generated during bacterial infection are required for secondary IgG responses to antigenic challenge (43.2)

Immunological memory was long considered to be harbored in B cells that express high affinity class-switched IgG. More recently, IgM memory B cells have been identified following immunization with nominal antigens and adjuvants. Based on the expression of CD11c, we have identified a large population of such cells using a natural model of infection by the bacterium Ehrlichia muris. These CD11c+ IgM memory cells exhibit phenotypic characteristics of memory B cells, including expression of CD73, CD11b, and PD-L2. In addition, these CD11c+ IgM memory cells lack expression of CD138, are largely quiescent, and have accumulated somatic mutations. Although these cells did not proliferate or secrete antibody ex vivo, they produced antigen-specific IgM upon in vitro stimulation with mitogens. Furthermore, in vivo depletion abrogated the IgG recall response to specific antigenic challenge. Our findings are consistent with previous data demonstrating that IgM memory cells undergo class switch recombination and affinity maturation following re-encounter with cognate antigen. We propose that these CD11c+ IgM memory B cells are responsible for the IgG produced following secondary challenge in ehrlichial infection, and likely function to provide greater flexibility to variant antigenic challenges.

Sperm traits in Chinook salmon depend upon activation medium: implications for studies of sperm competition in fishes

Sperm traits of externally fertilizing fish species are typically measured in fresh (or salt) water, even though the spawning environment of their ova contains ovarian fluid. In this study, we measured sperm traits of Chinook salmon ( Oncorhynchus tshawytscha (Walbaum in Artedi, 1792)) in both fresh water and dilute ovarian fluid at 10 and 20 s postactivation, using a computer-assisted sperm analysis system. Spermatozoa swam faster, and had both higher percent motility and a straighter path trajectory for a longer period of forward motility when activated in ovarian fluid compared with activation in fresh water. Comparing sperm activity of 10 males in water versus ovarian fluid, we found a weak but significant correlation for sperm swimming speed at 10 s postactivation (r = 0.34, p = 0.01), but not for any other sperm traits measured. Most important, across males, mean sperm swimming speed in water accounted for <10% of the observed variation in mean sperm swimming speed in ovarian fluid. Thus, we argue that sperm traits measured in fresh water are not particularly relevant to those same traits during normal spawning in this species. We suggest that sperm performance measured in fresh water should be used with caution when comparing the potential for individual males to fertilize ova, especially in studies of sperm competition in externally fertilizing species.

Formative design and evaluation of patient-delivered partner therapy informational materials and packaging

OBJECTIVE

To develop and evaluate instructional and packaging materials for patient-delivered partner therapy (PDPT).

METHODS

64 patients participated from an urban US sexually transmitted infection (STI) clinic. The research comprised three phases: individual interviews to elicit attitudes and beliefs regarding PDPT and to assess the understanding of key STI-related concepts and terminology; the development and rapid validation of prototype instructional and packaging materials for PDPT and interviews to assess the effectiveness, acceptability and usability of the prototype materials. Thematic qualitative data analysis was used to examine interview responses.

RESULTS

Participants were willing to deliver and receive PDPT and several potentially important related beliefs were identified. Participants indicated substantial unfamiliarity with words associated with STI treatment and some variability in definitions of sex partners. PDPT informational materials differentially affected participant willingness to receive (positively) and deliver (negatively) PDPT, positively influenced self-efficacy and understanding and were perceived as easy to use.

DISCUSSION

PDPT creates complex challenges for education, motivation and communication. Issues such as appropriate vocabulary and interpersonal trust may be amplified when responsibility for a medical procedure-dispensation of treatment-is shifted to patients. STI PDPT implementation can be augmented with effective, high-quality informational and packaging materials; however, several challenges exist.

The anti-neurodegeneration drug clioquinol inhibits the aging-associated protein CLK-1

The development of neurodegenerative diseases such as Alzheimer, Parkinson, and Huntington disease is strongly age-dependent. Discovering drugs that act on the high rate of aging in older individuals could be a means of combating these diseases. Reduction of the activity of the mitochondrial enzyme CLK-1 (also known as COQ7) slows down aging in Caenorhabditis elegans and in mice. Clioquinol is a metal chelator that has beneficial effects in several cellular and animal models of neurodegenerative diseases as well as on Alzheimer disease patients. Here we show that clioquinol inhibits the activity of mammalian CLK-1 in cultured cells, an inhibition that can be blocked by iron or cobalt cations, suggesting that chelation is involved in the mechanism of action of clioquinol on CLK-1. We also show that treatment of nematodes and mice with clioquinol mimics a variety of phenotypes produced by mutational reduction of CLK-1 activity in these organisms. These results suggest that the surprising action of clioquinol on several age-dependent neurodegenerative diseases with distinct etiologies might result from a slowing down of the aging process through action of the drug on CLK-1. Our findings support the hypothesis that pharmacologically targeting aging-associated proteins could help relieve age-dependent diseases.

Expression of AID transgene is regulated in activated B cells but not in resting B cells and kidney

Activation-induced DNA cytidine deaminase (AID) is required for somatic hypermutation (SHM) and efficient class switch recombination (CSR) of immunoglobulin (Ig) genes. We created AID-transgenic mice that express AID ubiquitously under the control of a beta-actin promoter. When crossed with AID-/- mice, the AID-transgenic,AID-/- mice carried out SHM and CSR, showing that the AID transgenes were functional. However, the frequencies of SHM in V- and switch-regions, and CSR were reduced compared to those in a wild type AID background. Several criteria suggested that the inefficiency of SHM was due to reduced AID activity, rather than lack of recruiting error-prone DNA repair. High levels of AID mRNA were produced in resting B cells and kidney, cells that do not express AID in wild type mice. Compared with these cells, activated B cells expressed about an order of magnitude less AID mRNA suggesting that there may be a post-transcriptional mechanism that regulates AID mRNA levels in professional AID producers but not other cells. The AID protein expressed in resting B cells and kidney was phosphorylated at serine-38. Despite this modification, known to enhance AID activity, resting B cells did not undergo SHM. Apparently, the large amounts of AID in resting B cells are not targeted to Ig genes in vivo, in contrast to findings in vitro.

Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure

Emissions of ammonia, as well as other gases and particulates, to the atmosphere are a growing concern of livestock producers, the general public, and regulators. The concentration and ruminal degradability of CP in beef cattle diets may affect urinary and fecal excretion of N and thus may affect ammonia emissions from beef cattle feed yards. To determine the effects of dietary CP concentration and degradability on potential ammonia emissions, 54 steers were randomly assigned to nine dietary treatments in a 3 x 3 factorial arrangement of treatments. Treatments consisted of three dietary CP concentrations (11.5, 13, and 14.5%) and three supplemental urea:cottonseed meal ratios (100:0, 50:50, and 0:100 of supplemental N). Steers were confined to tie stalls, and feces and urine excreted were collected and frozen after approximately 30, 75, and 120 d on feed. One percent of daily urine and feces excretion were added to polyethylene chambers containing 1,550 g of soil. Chambers were sealed, and ammonia emissions were trapped in an acid solution for 7 d using a vacuum system. As the protein concentration in the diet increased from 11.5 to 13%, in vitro daily ammonia emissions increased (P < 0.01) 60 to 200%, due primarily to increased urinary N excretion. As days on feed increased, in vitro ammonia emissions also increased (P < 0.01). Potential ammonia losses were highly correlated (P < 0.01) to urinary N (r2 = 0.69), urinary urea-N (r2 = 0.58) excretion, serum urea-N concentration (r2 = 0.52), and intake of degradable protein N (r2 = 0.23). Although dietary composition can affect daily ammonia losses, daily ammonia emissions must be balanced with effects on animal performance to determine optimal protein concentrations and forms in the diet.

Evolutionary conservation of drug action on lipoprotein metabolism-related targets

Genetic analysis has shown that the slower than normal rhythmic defecation behavior of the clk-1 mutants of Caenorhabditis elegans is the result of altered lipoprotein metabolism. We show here that this phenotype can be suppressed by drugs that affect lipoprotein metabolism, including drugs that affect HMG-CoA reductase activity, reverse cholesterol transport, or HDL levels. These pharmacological effects are highly specific, as these drugs affect defecation only in clk-1 mutants and not in the wild-type and do not affect other behaviors of the mutants. Furthermore, drugs that affect processes not directly related to lipid metabolism show no or minimal activity. Based on these findings, we carried out a compound screen that identified 190 novel molecules that are active on clk-1 mutants, 15 of which also specifically decrease the secretion of apolipoprotein B (apoB) from HepG2 hepatoma cells. The other 175 compounds are potentially active on lipid-related processes that cannot be targeted in cell culture. One compound, CHGN005, was tested and found to be active at reducing apoB secretion in intestinal Caco-2 cells as well as in HepG2 cells. This compound was also tested in a mouse model of dyslipidemia and found to decrease plasma cholesterol and triglyceride levels. Thus, target processes for pharmacological intervention on lipoprotein synthesis, transport, and metabolism are conserved between nematodes and vertebrates, which allows the use of C. elegans for drug discovery.

ATM prevents the persistence and propagation of chromosome breaks in lymphocytes

DNA double-strand breaks (DSBs) induce a signal transmitted by the ataxia-telangiectasia mutated (ATM) kinase, which suppresses illegitimate joining of DSBs and activates cell-cycle checkpoints. Here we show that a significant fraction of mature ATM-deficient lymphocytes contain telomere-deleted ends produced by failed end joining during V(D)J recombination. These RAG-1/2 endonuclease-dependent, terminally deleted chromosomes persist in peripheral lymphocytes for at least 2 weeks in vivo and are stable over several generations in vitro. Restoration of ATM kinase activity in mature lymphocytes that have transiently lost ATM function leads to loss of cells with terminally deleted chromosomes. Thus, maintenance of genomic stability in lymphocytes requires faithful end joining as well a checkpoint that prevents the long-term persistence and transmission of DSBs. Silencing this checkpoint permits DNA ends produced by V(D)J recombination in a lymphoid precursor to serve as substrates for translocations with chromosomes subsequently damaged by other means in mature cells.

Men with broken condoms: who and why?

OBJECTIVES

To identify (1) the prevalence of condom breakage, and demographic and sexuality-related differences among young men who have sex with women reporting and not reporting this event; (2) condom-specific behaviours associated with breakage.

METHODS

Young men (n = 278) attending a clinic for treatment of sexually transmitted infections (STIs) responded to an anonymous questionnaire aided by a CD recording of the questions. The samples were screened to include only men who had used a condom during penile-vaginal sex at least three times in the past 3 months. Condom-specific behaviours (including breakage) were assessed using these last three acts of condom use as the recall period. Correlates achieving bivariate significance were subjected to multivariate analysis.

RESULTS

Nearly one third (31.3%) of the men reported recent breakage. The breakage rate was 15%. Three correlates significantly distinguished between men who did and did not report breakage. Men who had past STIs were more likely to report breakage (adjusted odds ratio (AOR) 2.08), as were men who also reported condom slippage (AOR 2.72). Less self-efficacy for correct condom use was also significantly associated with breakage (AOR 1.07). Further, three condom-specific behaviours were significantly associated with breakage: allowing condoms to contact sharp objects (AOR 2.6), experiencing problems with the "fit or feel" of condoms (AOR 2.3) and not squeezing air from the receptacle tip (AOR 2.0).

CONCLUSIONS

Breakage may be common and may occur in a larger context of difficulties with condoms. STI clinics could potentially benefit some men by providing instructions on the correct use of condoms.

The Role of Activation‐Induced Deaminase in Antibody Diversification and Chromosome Translocations

Although B and T lymphocytes are similar in many respects including diversification of their antigen receptor genes by V(D)J recombination, 95% of all lymphomas diagnosed in the western world are of B-cell origin. Many of these are derived from mature B cells [Kuppers, R. (2005). Mechanisms of B-cell lymphoma pathogenesis. Nat. Rev. Cancer 5, 251-262] and display hallmark chromosome translocations involving immunoglobulin genes and a proto-oncogene partner whose expression becomes deregulated as a result of the translocation reaction [Kuppers, R. (2005). Mechanisms of B-cell lymphoma pathogenesis. Nat. Rev. Cancer 5, 251-262; Kuppers, R., and Dalla-Favera, R. (2001). Mechanisms of chromosomal translocations in B cell lymphomas. Oncogene 20, 5580-5594]. These translocations are essential to the etiology of B-cell neoplasms. Here we will review how the B-cell specific molecular events required for immunoglobulin class switch recombination are initiated and how they contribute to chromosome translocations in vivo.