Differential impact of a dyskeratosis congenita mutation in TPP1 on mouse hematopoiesis and germline

A TPP1 mutation known to cause telomere shortening and bone marrow failure in humans recapitulates telomere loss but results in severe germline defects in mice without impacting murine hematopoiesis.

Telomerase extends chromosome ends in somatic and germline stem cells to ensure continued proliferation. Mutations in genes critical for telomerase function result in telomeropathies such as dyskeratosis congenita, frequently resulting in spontaneous bone marrow failure. A dyskeratosis congenita mutation in TPP1 (K170∆) that specifically compromises telomerase recruitment to telomeres is a valuable tool to evaluate telomerase-dependent telomere length maintenance in mice. We used CRISPR-Cas9 to generate a mouse knocked in for the equivalent of the TPP1 K170∆ mutation (TPP1 K82∆) and investigated both its hematopoietic and germline compartments in unprecedented detail. TPP1 K82∆ caused progressive telomere erosion with increasing generation number but did not induce steady-state hematopoietic defects. Strikingly, K82∆ caused mouse infertility, consistent with gross morphological defects in the testis and sperm, the appearance of dysfunctional seminiferous tubules, and a decrease in germ cells. Intriguingly, both TPP1 K82∆ mice and previously characterized telomerase knockout mice show no spontaneous bone marrow failure but rather succumb to infertility at steady-state. We speculate that telomere length maintenance contributes differently to the evolutionary fitness of humans and mice.

Discovery of first-in-class inhibitors of ASH1L histone methyltransferase with anti-leukemic activity

ASH1L histone methyltransferase plays a crucial role in the pathogenesis of different diseases, including acute leukemia. While ASH1L represents an attractive drug target, developing ASH1L inhibitors is challenging, as the catalytic SET domain adapts an inactive conformation with autoinhibitory loop blocking the access to the active site. Here, by applying fragment-based screening followed by medicinal chemistry and a structure-based design, we developed first-in-class small molecule inhibitors of the ASH1L SET domain. The crystal structures of ASH1L-inhibitor complexes reveal compound binding to the autoinhibitory loop region in the SET domain. When tested in MLL leukemia models, our lead compound, AS-99, blocks cell proliferation, induces apoptosis and differentiation, downregulates MLL fusion target genes, and reduces the leukemia burden in vivo. This work validates the ASH1L SET domain as a druggable target and provides a chemical probe to further study the biological functions of ASH1L as well as to develop therapeutic agents.

TPP1 mutagenesis screens unravel shelterin interfaces and functions in hematopoiesis

Telomerase catalyzes chromosome end replication in stem cells and other long-lived cells. Mutations in telomerase or telomere-related genes result in diseases known as telomeropathies. Telomerase is recruited to chromosome ends by the ACD/TPP1 protein (TPP1 hereafter), a component of the shelterin complex that protects chromosome ends from unwanted end joining. TPP1 facilitates end protection by binding shelterin proteins POT1 and TIN2. TPP1 variants have been associated with telomeropathies but remain poorly characterized in vivo. Disease variants and mutagenesis scans provide efficient avenues to interrogate the distinct physiological roles of TPP1. Here, we conduct mutagenesis in the TIN2- and POT1-binding domains of TPP1 to discover mutations that dissect TPP1's functions. Our results extend current structural data to reveal that the TPP1-TIN2 interface is more extensive than previously thought and highlight the robustness of the POT1-TPP1 interface. Introduction of separation-of-function mutants alongside known TPP1 telomeropathy mutations in mouse hematopoietic stem cells (mHSCs) lacking endogenous TPP1 demonstrated a clear phenotypic demarcation. TIN2- and POT1-binding mutants were unable to rescue mHSC failure resulting from end deprotection. In contrast, TPP1 telomeropathy mutations sustained mHSC viability, consistent with their selectively impacting end replication. These results highlight the power of scanning mutagenesis in revealing structural interfaces and dissecting multifunctional genes.

Definitions, indications and practice of urotherapy in children and adolescents: - A standardization document of the International Children's Continence Society (ICCS)

BACKGROUND

Urotherapy is an umbrella term for all non-surgical, non-pharmacological interventions for lower urinary tract disorders (LUTD) in children and adolescents. Urotherapy is a specialized practice, which has become mainstay therapy not only for daytime urinary incontinence, but also for nocturnal enuresis, functional constipation and fecal incontinence. The aim of urotherapy is to achieve the normalization of the micturition and bowel pattern and to prevent further functional disturbances by repeated training. It is well known that in the treatment of adult and childhood incontinence a team approach is best, where there are shared areas of expertise and also discipline-specific expertise available.

AIM

We present a consensus view from a cross-professional team of experts affiliated with the International Children's Continence Society on definitions, indications and practice of urotherapy. This is a selective, non-systematic review with practical recommendations for the implementation and research on urotherapy.

METHODS

The document uses the globally accepted ICCS terminology. Evidence-based literature serves as the basis, but in areas lacking in primary evidence, expert consensus is used. Before submission, a full draft was made available to all ICCS members for additional comments.

RESULTS

Urotherapy uses non-pharmacological, non-surgical methods and focuses on behavioral interventions, largely based on cognitive-behavioral psychotherapy (CBT). Standard urotherapy comprises components such as provision of information, instructions, life-style advice, counselling and registration of symptoms. Specific urotherapy is tailored towards specific disorders and includes alarm treatment, biofeedback training, pelvic floor training, neurostimulation and other interventions. Fig. 1. Urotherapy is a treatment that addresses all aspects of incontinence, leading to the best clinical outcome. This includes somatic, psychosocial, and behavioral problems and quality of life. Therefore urotherapy is recommended by the ICCS as the first-line treatment for most types of LUTD. The document is intended to be clinically useful in primary, secondary and tertiary care.

Elucidating the Importance of DOT1L Recruitment in MLL-AF9 Leukemia and Hematopoiesis

MLL1 (KMT2a) gene rearrangements underlie the pathogenesis of aggressive MLL-driven acute leukemia. AF9, one of the most common MLL-fusion partners, recruits the histone H3K79 methyltransferase DOT1L to MLL target genes, constitutively activating transcription of pro-leukemic targets. DOT1L has emerged as a therapeutic target in patients with MLL-driven leukemia. However, global DOT1L enzymatic inhibition may lead to off-target toxicities in non-leukemic cells that could decrease the therapeutic index of DOT1L inhibitors. To bypass this problem, we developed a novel approach targeting specific protein-protein interactions (PPIs) that mediate DOT1L recruitment to MLL target genes, and compared the effects of enzymatic and PPIs inhibition on leukemic and non-leukemic hematopoiesis. MLL-AF9 cell lines were engineered to carry mutant DOT1L constructs with a defective AF9 interaction site or lacking enzymatic activity. In cell lines expressing a DOT1L mutant with defective AF9 binding, we observed complete disruption of DOT1L recruitment to critical target genes and inhibition of leukemic cell growth. To evaluate the overall impact of DOT1L loss in non-leukemic hematopoiesis, we first assessed the impact of acute Dot1l inactivation in adult mouse bone marrow. We observed a rapid reduction in myeloid progenitor cell numbers within 7 days, followed by a loss of long-term hematopoietic stem cells. Furthermore, WT and PPI-deficient DOT1L mutants but not an enzymatically inactive DOT1L mutant were able to rescue sustained hematopoiesis. These data show that the AF9-DOT1L interaction is dispensable in non-leukemic hematopoiesis. Our findings support targeting of the MLL-AF9-DOT1L interaction as a promising therapeutic strategy that is selectively toxic to MLL-driven leukemic cells.

Bacillus subtilis: a potential growth promoter in weaned pigs in comparison to carbadox

The study was conducted to investigate the efficacy of a probiotic Bacillus subtilis strain on growth performance, diarrhea, systemic immunity, and intestinal health of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli and to compare the efficacy of B. subtilis with that of carbadox. Weaned pigs (n = 48, 6.17 ± 0.36 kg body weight [BW]) were individually housed in disease containment rooms and randomly allotted to one of four dietary treatments: negative control (NC, control diet without E. coli challenge), positive control (PC, control diet with E. coli challenge), and supplementation of 50 mg/kg of carbadox (antibiotic growth promotor [AGP]) or 2.56 × 109 CFU/kg of B. subtilis probiotics (PRO). The experiment lasted for 28 d with 7 d before and 21 d after the first E. coli inoculation. Fecal and blood samples were collected on days 0, 3, 7, 14, and 21 post inoculation (PI) to analyze β-hemolytic coliforms and complete blood cell count, respectively. Diarrhea score was recorded daily for each pig to calculate the frequency of diarrhea. All pigs were euthanized at day 21 PI to collect jejunal and ileal mucosa for gene expression analysis. Pigs in AGP had greater (P < 0.05) BW on days 7, 14, and 21 PI than pigs in PC and PRO groups. Supplementation of PRO enhanced pigs' BW on day 21 PI compared with the PC. Escherichia coli F18 challenge reduced (P < 0.05) average daily gain (ADG) and feed efficiency from day 0 to 21 PI, while supplementation of carbadox or PRO enhanced ADG and feed efficiency in E. coli F18-challenged pigs from day 0 to 21 PI. Pigs in AGP and PRO groups had reduced (P < 0.05) frequency of diarrhea throughout the experiment and fecal β-hemolytic coliforms on day 7 PI than pigs in the PC. Pigs in PRO had greater (P < 0.05) gene expression of CLDN1 in jejunal mucosa than pigs in the PC. Supplementation of carbadox or PRO reduced (P < 0.05) the gene expression of IL6 and PTGS2 in ileal mucosa of E. coli-infected pigs compared with pigs in the PC. Pigs in the PRO group had lower (P < 0.05) white blood cell number and neutrophil count, and serum haptoglobin concentration on day 7 PI, and less (P < 0.05) monocyte count on day 14 PI, compared with PC. In conclusion, supplementation of probiotic B. subtilis could enhance disease resistance and promote the growth performance of weaned pigs under disease challenge conditions. The potential mechanisms include but not limited to enhanced gut barrier integrity and local and systemic immune responses of weaned pigs.

Determining the effects of insulin Detemir on endogenous secretion of insulin

Type 2 diabetes (T2D) is a long-term metabolic disorder. A pilot trial was designed to investigate the effects of the long acting insulin Detemir on endogenous insulin secretion, to assess use in early T2D care. Provesn metabolic system models are used to identify patient-specific insulin sensitivity and endogenous insulin secretion from clinical data. Post-cardiac surgery patients with early T2D or pre-diabetes based on HbA1c were given a bolus of insulin Detemir on one day, and none on the second day in hospital. Blood glucose, insulin, C-Peptide, and all nutrition given are recorded. Early results from N=3 patients show 0.8-1.0U/hour insulin Detemir doses have no apparent suppression of endogenous insulin secretion, but does help lower glucose levels. The results show the model captures glucose-insulin dynamics in pre-diabetic post-surgical patients, and insulin Detemir may be useful to support individuals with pre-diabetes in reducing blood glucose levels. Tests with higher doses, need to be carried out to verify these results over a greater range of patients.

Association between herd management practices and antimicrobial resistance in Salmonella spp. from cull dairy cattle in Central California

Background

In this study cull dairy cows from six California dairy herds were sampled seasonally over the course of a year. The objectives were to determine the prevalence of antimicrobial resistant (AMR) Salmonella spp. shed in cull cow feces, and the factors associated with fecal shedding of AMR and multidrug resistant (MDR) Salmonella.

Methods

Six dairy farms located in the San Joaquin Valley of California were identified and enrolled as a convenience sample. On each dairy, and once during each of the four seasons, 10 cull cows were randomly selected for fecal sampling on the day of their removal from the herd. In addition, study personnel completed a survey based on responses of the herd manager to questions related to the previous 4 month's herd management and the specific cattle sampled. Fecal samples were submitted to the California Animal Health and Food Safety laboratory for Salmonella isolation. Antimicrobial resistance was evaluated using broth microdilution method and a gram-negative assay plate following Clinical Laboratory Standards Institute (CLSI) guidelines and breakpoint references. All statistical models were survey adjusted for number of animals on sampling day.

Results

A total of 62 Salmonella were isolated from 60 of the 239 fecal samples collected. For 12% (95% confidence interval (CI) [3-20]) of fecal samples a multidrug resistant Salmonella was isolated. The survey-weighted results for the two most common drug classes for which isolates were resistant were tetracycline (39%; 95% CI [27-51]) and ampicillin (18%; 95% CI [9-27]). An important finding was the identification of cephalosporin as the third most common drug class for which isolates were resistant, with ceftriaxone (10%; 95% CI [2-17]) being the most common drug associated with resistance in that class. At the cow-level, reason for culling, prior treatment with antimicrobial drugs as the reason for culling was associated with higher odds of isolating an AMR Salmonella isolate. At the herd-level, percent of animals monthly culled on the farm as well as number of milking cows in the herd were associated with isolation of antimicrobial resistant Salmonella in cull cows.

Discussion

Salmonella isolated from fecal samples from cull cows were resistant to important antimicrobials, such as ceftriaxone. The most common drug classes for which isolates were resistant were tetracyclines and beta-lactams, with ampicillin, ceftriaxone and ceftiofur being the three most common drugs within the latter. Cow and herd level factors were associated with isolating antimicrobial resistant Salmonella that should be further investigated for their potential role in promoting occurrence of AMR Salmonella. Our results also highlight the importance of monitoring dairy cattle sent to slaughter for shedding of Salmonella resistant to medically important antimicrobial drugs.

Abstract 1380: Towards peptidomimetics to target DOT1L recruitment in MLL-AF9 leukemia

Leukemias harboring rearrangements of mixed-lineage leukemia gene (MLL1) are associated with poor clinical outcomes, and new therapeutic approaches are needed. Rearrangement of the MLL1 gene generates fusion oncoproteins which drive the high expression of the clustered homeobox (HOX) genes and induce leukemic transformation. Genome-wide histone methylation studies have revealed that the abnormal expression of MLL1 fusion target genes is associated with high levels of histone H3 lysine 79 (H3K79) methylation. Recruitment of DOT1L (disruptor of telomeric silencing 1-like), a unique histone methyltransferase that catalyzes methylation of H3K79, proved to be essential for the transforming activity of multiple MLL fusion proteins. We have mapped the binding site to a short segment of 10 amino acids in DOT1L and shown that DOT1L mutants lacking these residues did not support transformation by MLL-AF9. We hypothesized that by targeting the AF9-DOT1L protein-protein interactions (PPIs), we would selectively kill MLL-AF9 cells without effecting DOT1L role in normal hematopoiesis. Using established DOT1Lf/f MLL-AF9 with reintroduced WT-DOT1L, DOT1L missing 10aa AF9-binding domain (D10), DOT1L with a point mutation in the AF9-binding domain (I867A) and enzymatically inactive DOT1L (RCR), we were able to demonstrate that by disrupting the AF9-DOT1L PPIs, although we can inhibit leukemogenesis similarly to enzymatic inhibition, this interaction is not essential for normal hematopoiesis. Based on our initial studies to map the DOT1L interaction site and in conjunction with utilizing reported NMR structures of the AF9-DOT1L complex, we investigated the nature of the interactions and the minimum length of the peptide. Using different natural and unnatural amino acids, we successfully designed a 7mer peptide with KD of 10 nM and 25 nM against AF9 and ENL, respectively, showing similar potency as the originally identified and validated 10mer peptide. These results lay the groundwork for further optimization of the 7mer peptide towards developing DOT1L peptidomimetics with improved potency and cellular activity, to further validate the PPIs between DOT1L and MLL-fusion proteins as a potential therapeutic target for MLL rearranged leukemia.

Citation Format: Sierrah Marie Grigsby, Jennifer Chase, Bridget Waas, Ann Friedman, Lei Du, Aihong Yao, James Ropa, Justin Serio, Andrew Muntean, Ivan Maillard, Haying Sun, Zaneta Nikolovska-Coleska. Towards peptidomimetics to target DOT1L recruitment in MLL-AF9 leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1380.

Loss of mTORC1 signaling alters pancreatic α cell mass and impairs glucagon secretion

Glucagon plays a major role in the regulation of glucose homeostasis during fed and fasting states. However, the mechanisms responsible for the regulation of pancreatic α cell mass and function are not completely understood. In the current study, we identified mTOR complex 1 (mTORC1) as a major regulator of α cell mass and glucagon secretion. Using mice with tissue-specific deletion of the mTORC1 regulator Raptor in α cells (αRaptorKO), we showed that mTORC1 signaling is dispensable for α cell development, but essential for α cell maturation during the transition from a milk-based diet to a chow-based diet after weaning. Moreover, inhibition of mTORC1 signaling in αRaptorKO mice and in WT animals exposed to chronic rapamycin administration decreased glucagon content and glucagon secretion. In αRaptorKO mice, impaired glucagon secretion occurred in response to different secretagogues and was mediated by alterations in KATP channel subunit expression and activity. Additionally, our data identify the mTORC1/FoxA2 axis as a link between mTORC1 and transcriptional regulation of key genes responsible for α cell function. Thus, our results reveal a potential function of mTORC1 in nutrient-dependent regulation of glucagon secretion and identify a role for mTORC1 in controlling α cell-mass maintenance.

Abstract 5489: Using genetic and chemical approaches to probe the mechanism of DOT1L recruitment in MLL fusion leukemia

Mixed lineage leukemia (MLL) is an aggressive form of leukemia where the MLL gene is translocated and fused to more than 80 different nuclear, cytoplasmic and membrane proteins. MLL-AF9 is one of the most common MLL-fusions. This fusion partner is known to recruit several multiprotein complexes including the AEP, SEC and DOT1L complexes leading to transcriptional activation. In particular, the recruitment of Disruptor of telomeric silencing 1-like (DOT1L), a H3K79 histone methyltransferase, is essential for leukemogenesis by multiple MLL fusion proteins. We mapped the binding site to a 10 amino acid segment (865 - 874) on DOT1L where AF9 binds. Peptides derived from this region that show dose-dependent disruption of this interaction. We also demonstrated that DOT1L mutants lacking these 10 residues did not support transformation by MLL-AF9. Encouraged by these results, we generated both genetic and chemical tools to elucidate the role of DOT1L recruitment to the MLL fusion partners and the mechanism of leukemogenic inhibition by disrupting the protein-protein interaction (PPI) between MLL-AF9 and DOT1L. Fl/Fl DOT1L MLL-AF9 Cre+ cell lines were generated with different constructs of DOT1L. These constructs consisted of DOT1L mutants lacking the 10 amino acid binding site, a I867A point mutant known to block DOT1L binding, and an enzymatic mutant known to yield a catalytically inactive protein. As control cell lines, MLL-AF6, a MLL-fusion containing a cytoplasmic protein, and E2A-HLF, a non-DOT1L dependent fusion, were generated to demonstrate the specific effects of generated DOT1L mutant constructs. Both DOT1L PPI mutants impaired the transformation by MLL-AF9 and induced cell death by inducing apoptosis and cell cycle arrest similarly to enzymatic inhibition. These results established a foundation for discovering small-molecule inhibitors that disrupting the AF9-DOT1L as potential disease-specific therapies that target chromatin modifications in this highly aggressive leukemia. A high throughput screening was conducted identifying several different chemical classes of small molecules that bind to the AF9 C-terminal hydrophobic binding site and disrupt the PPI between DOT1L and MLL-AF9 fusion protein. Identified small molecule inhibitors were validated with series of biochemical, functional and cell-based assays. Validated compounds selectively inhibit the growth of the DOT1L dependent murine cells and induce cell death in a similar manner to the genetic approach. The small molecules also showed specificity in killing human MLL-fusion cell lines in comparison to non-MLL fusion leukemia. These results show that blocking the recruitment of DOT1L by AF9 using both genetic and chemical tools eliminate MLL-AF9 mediated immortalization emphasizing an essential function for this interaction in leukemogenesis and warrant further development of the identified small-molecule inhibitors.

Citation Format: Sierrah M. Grigsby, James Ropa, Justin Serio, Chenxi Shen, Jennifer Chase, Ivan Maillard, Andrew Muntean, Zaneta Nikolovska-Coleska. Using genetic and chemical approaches to probe the mechanism of DOT1L recruitment in MLL fusion leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5489. doi:10.1158/1538-7445.AM2017-5489

Abstract 3803: Development of genetic and chemical tools for understanding the recruitment of DOT1L in MLL-fusion driven leukemia and normal hematopoiesis

Leukemias harboring rearrangements of mixed-lineage leukemia gene (MLL1) are associated with poor clinical outcomes, and new therapeutic approaches are needed. Rearrangements of the MLL1 gene generate fusion oncoproteins which drive the high expression of the clustered homeobox (HOX) genes and induce leukemic transformation. Genome wide histone methylation studies have revealed that the abnormal expression of MLL1 fusion target genes is associated with high levels of histone H3 lysine 79 (H3K79) methylation. Recruitment of DOT1L (disruptor of telomeric silencing 1-like), a unique histone methyltransferase that catalyzes methylation of H3K79, proved to be essential for the transforming activity of multiple MLL fusion proteins. To gain insights into the unique functions of DOT1L in MLL-driven leukemia, we elucidated the mechanisms of DOT1L recruitment to the MLL fusion partners. The binding site was mapped to a short segment of 10 amino acids in DOT1L and peptides derived from this region disrupted the interaction between DOT1L and MLL-AF9. DOT1L mutants lacking these 10 residues did not support transformation by MLL-AF9. This discovery has established a foundation for disease-specific therapies that target chromatin modifications in highly malignant leukemias. Applying high throughput screening approach several different chemical classes of small molecules that disrupt the protein-protein interactions between DOT1L and oncogenic MLL-fusion proteins were identified and validated. To evaluate if the AF9-binding domain of DOT1L is critical for its functions in normal hematopoietic stem cells as opposed to leukemias driven by MLL fusion proteins, genetic tools were developed to functionally investigate the importance of the DOT1L AF9-binding domain in MLL-AF9-driven leukemia and its role in the physiological functions of DOT1L in normal hematopoiesis. Our findings demonstrate that pharmacological inhibition of the DOT1L complex through disrupting the AF9-DOT1L interactions may provide therapeutic benefits in an array of malignancies with abnormal HOXA gene expression.

Citation Format: Sierrah Grigsby, Jennifer Chase, James Ropa, Justin Serio, Chenxi Shen, Martha Larsen, Preston Donover, Melvin Reichman, Andrew Muntean, Ivan Maillard, Zaneta Nikolovska-Coleska. Development of genetic and chemical tools for understanding the recruitment of DOT1L in MLL-fusion driven leukemia and normal hematopoiesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3803.

Safety restraint injuries in fatal motor vehicle collisions

The presence of an apparent seat belt mark (SBM) on a car crash occupant is often used as evidence for use of a seat belt at the time of the crash and, conversely, the lack of a SBM is used as an indication that no seat belt was used. This study examined whether there are clear indications of seat belt use to be found at autopsy and evaluated the sensitivity and specificity of apparent SBM and whether the use of a seat belt and seating location affects the type and severity of injuries sustained. Information on the type of injuries sustained and seatbelt use was retrieved from autopsy reports and police reports, respectively, for cases of fatal motor vehicle collisions occurring in Sydney, Australia over a 5-year period. In this study, a SBM was only found on restrained occupants. The proportion of restrained occupants with evidence of a SBM was 36% (sensitivity), whilst unrestrained occupants showed no evidence of a SBM (100% specificity). A SBM was also found to reliably reflect the seating position of the occupant. We conclude that restrained occupants can be expected to show evidence of the seat belt in just over one third of cases and that the absence of a SBM is not necessarily an indication that no seat belt was used. Spurious SBM is very unlikely to be present if the occupant was unrestrained.

Pancreatic SEC23B deficiency is sufficient to explain the perinatal lethality of germline SEC23B deficiency in mice

In humans, loss of function mutations in SEC23B result in Congenital Dyserythropoietic Anemia type II (CDAII), a disease limited to defective erythroid development. Patients with two nonsense SEC23B mutations have not been reported, suggesting that complete SEC23B deficiency might be lethal. We previously reported that SEC23B-deficient mice die perinatally, exhibiting massive pancreatic degeneration and that mice with hematopoietic SEC23B deficiency do not exhibit CDAII. We now show that SEC23B deficiency restricted to the pancreas is sufficient to explain the lethality observed in mice with global SEC23B-deficiency. Immunohistochemical stains demonstrate an acinar cell defect but normal islet cells. Mammalian genomes contain two Sec23 paralogs, Sec23A and Sec23B. The encoded proteins share ~85% amino acid sequence identity. We generate mice with pancreatic SEC23A deficiency and demonstrate that these mice survive normally, exhibiting normal pancreatic weights and histology. Taken together, these data demonstrate that SEC23B but not SEC23A is essential for murine pancreatic development. We also demonstrate that two BAC transgenes spanning Sec23b rescue the lethality of mice homozygous for a Sec23b gene trap allele, excluding a passenger gene mutation as the cause of the pancreatic lethality, and indicating that the regulatory elements critical for Sec23b pancreatic function reside within the BAC transgenes.

Management of functional nonretentive fecal incontinence in children: Recommendations from the International Children's Continence Society

BACKGROUND

Fecal incontinence (FI) in children is frequently encountered in pediatric practice, and often occurs in combination with urinary incontinence. In most cases, FI is constipation-associated, but in 20% of children presenting with FI, no constipation or other underlying cause can be found - these children suffer from functional nonretentive fecal incontinence (FNRFI).

OBJECTIVE

To summarize the evidence-based recommendations of the International Children's Continence Society for the evaluation and management of children with FNRFI.

RECOMMENDATIONS

Functional nonretentive fecal incontinence is a clinical diagnosis based on medical history and physical examination. Except for determining colonic transit time, additional investigations are seldom indicated in the workup of FNRFI. Treatment should consist of education, a nonaccusatory approach, and a toileting program encompassing a daily bowel diary and a reward system. Special attention should be paid to psychosocial or behavioral problems, since these frequently occur in affected children. Functional nonretentive fecal incontinence is often difficult to treat, requiring prolonged therapies with incremental improvement on treatment and frequent relapses.

Fecal Indicator and Pathogenic Bacteria and Their Antibiotic Resistance in Alluvial Groundwater of an Irrigated Agricultural Region with Dairies

Surveys of microbiological groundwater quality were conducted in a region with intensive animal agriculture in California, USA. The survey included monitoring and domestic wells in eight concentrated animal feeding operations (CAFOs) and 200 small (domestic and community supply district) supply wells across the region. was not detected in groundwater, whereas O157:H7 and were each detected in 2 of 190 CAFO monitoring well samples. Nonpathogenic generic and spp. were detected in 24.2% (46/190) and 97.4% (185/190) groundwater samples from CAFO monitoring wells and in 4.2% (1/24) and 87.5% (21/24) of CAFO domestic wells, respectively. Concentrations of both generic and spp. were significantly associated with well depth, season, and the type of adjacent land use in the CAFO. No pathogenic bacteria were detected in groundwater from 200 small supply wells in the extended survey. However, 4.5 to 10.3% groundwater samples were positive for generic and . Concentrations of generic were not significantly associated with any factors, but concentrations of were significantly associated with proximity to CAFOs, seasons, and concentrations of potassium in water. Among a subset of and isolates from both surveys, the majority of (63.6%) and (86.1%) isolates exhibited resistance to multiple (≥3) antibiotics. Findings confirm significant microbial and antibiotic resistance loading to CAFO groundwater. Results also demonstrate significant attenuative capacity of the unconfined alluvial aquifer system with respect to microbial transport.

Pharmacologic inhibition of the Menin-MLL interaction blocks progression of MLL leukemia in vivo

Chromosomal translocations affecting mixed lineage leukemia gene (MLL) result in acute leukemias resistant to therapy. The leukemogenic activity of MLL fusion proteins is dependent on their interaction with menin, providing basis for therapeutic intervention. Here we report the development of highly potent and orally bioavailable small-molecule inhibitors of the menin-MLL interaction, MI-463 and MI-503, and show their profound effects in MLL leukemia cells and substantial survival benefit in mouse models of MLL leukemia. Finally, we demonstrate the efficacy of these compounds in primary samples derived from MLL leukemia patients. Overall, we demonstrate that pharmacologic inhibition of the menin-MLL interaction represents an effective treatment for MLL leukemias in vivo and provide advanced molecular scaffold for clinical lead identification.

Ash1l controls quiescence and self-renewal potential in hematopoietic stem cells

Rapidly cycling fetal and neonatal hematopoietic stem cells (HSCs) generate a pool of quiescent adult HSCs after establishing hematopoiesis in the bone marrow. We report an essential role for the trithorax group gene absent, small, or homeotic 1-like (Ash1l) at this developmental transition. Emergence and expansion of Ash1l-deficient fetal/neonatal HSCs were preserved; however, in young adult animals, HSCs were profoundly depleted. Ash1l-deficient adult HSCs had markedly decreased quiescence and reduced cyclin-dependent kinase inhibitor 1b/c (Cdkn1b/1c) expression and failed to establish long-term trilineage bone marrow hematopoiesis after transplantation to irradiated recipients. Wild-type HSCs could efficiently engraft when transferred to unirradiated, Ash1l-deficient recipients, indicating increased availability of functional HSC niches in these mice. Ash1l deficiency also decreased expression of multiple Hox genes in hematopoietic progenitors. Ash1l cooperated functionally with mixed-lineage leukemia 1 (Mll1), as combined loss of Ash1l and Mll1, but not isolated Ash1l or Mll1 deficiency, induced overt hematopoietic failure. Our results uncover a trithorax group gene network that controls quiescence, niche occupancy, and self-renewal potential in adult HSCs.

Effects of racing on reticulocyte concentrations in Greyhounds

BACKGROUND

Greyhounds have several hematologic variables that are outside of the respective reference intervals of other dog breeds. In addition, increases in HCT, total protein and HGB concentration, and RBC and WBC counts occur immediately after exercise; these values return to resting values within a few hour after racing.

OBJECTIVE

This study evaluated the effects of exercise on the concentration of reticulocytes in circulating blood in racing Greyhounds. We hypothesized that reticulocyte numbers are significantly increased immediately after a race, and return to baseline within one to 2 h postrace.

METHODS

Fifty actively racing Greyhounds at the Wheeling Island Racetrack and Casino were included in the study. Samples were collected by jugular venipuncture one day prior to racing at the kennel (resting), immediately after racing, and one to 2 h after the race (recovery). Reticulocyte counts were determined with an IDEXX ProCyte Dx Hematology Analyzer (IDEXX Laboratories, Inc., Westbrook, ME, USA). Due to a nonparametric distribution, the results were statistically compared using the Friedman test.

RESULTS

Reticulocyte concentrations were significantly different among the 3 sample collection times (P < .0001). There was a significant increase in reticulocyte concentration immediately after racing (P < .001); one to 2 h after racing, the reticulocyte numbers decreased significantly (P < .001) to counts comparable to resting samples.

CONCLUSION

The increase in reticulocyte concentration is probably related to splenic contraction secondary to the release of catecholamines, although premature bone marrow release could also account for these changes. Thus, it is important to consider a Greyhound's activity and degree of excitement when interpreting selected hematologic data in a clinical setting.

Structural correlation between cuticular hydrocarbons and female contact sex pheromone of German cockroachBlattella germanica (L.)

The structural relationships between the cuticular hydrocarbons and the contact sex pheromone of the female German cockroach,Blattella germanica, were investigated. Cuticular hexane extracts were separated into hydrocarbon and ketone fractions by TLC or silicic acid column chromatography. The ketone fraction (which contains the major contact sex pheromone component) was analyzed by GC-MS before and after reduction to ydrocarbon. In addition to 3,11-dimethyl-2-nonacosanone, 3,11-dimethyl-2-heptacosanone was also identified. Females have the 3,11- and 3,9-dimethyl C27 and C29 alkanes, but only the 3,11- isomer of the dimethylketones. Inddition to the hydrocarbon components previously reported, a number of new components were characterized. Although the ratios of cuticular hydrocarbons differ among nymphs, adult males, and adult females, they have qualitatively identical hydrocarbon profiles, suggesting that the production of the contact sex pheromone results from the sex-specific oxidation of 3,11-imethylalkanes to pheromone components by the female.

Improving ascertainment of risk factors for HIV infection: results of a group-randomized evaluation

To allow appropriate allocation of prevention and care funding, HIV/AIDS surveillance data must include risk factor information, currently available for less than 70% of cases reported in the United States. The authors evaluated an intervention consisting of provider training and materials to improve risk factor reporting. Facilities were matched prior to randomization to intervention or control, and generalized linear mixed models were used to test for an intervention effect. Twenty-one percent of cases from intervention facilities and 33.4% from control facilities (p = .09) were reported without any risk factor information. The pre-post difference (20.7% for intervention and 36.0% for control) was not significant among HIV cases (p = .11) nor among AIDS cases (p = .12; 21.3% for intervention and 31.1% for control). The methods the authors' evaluated may need to be combined with other approaches and/or alternative classification schemes to significantly reduce the percentage of cases reported to surveillance without risk factor information.

Study of ventricular interaction during pulmonary embolism using clinical identification in a minimum cardiovascular system model

Cardiovascular disturbances are difficult to diagnose and treat because of the large range of possible underlying dysfunctions combined with regulatory reflex mechanisms that can result in conflicting clinical data. Thus, medical professionals often rely on experience and intuition to optimize hemodynamics in the critically ill. This paper combines an existing minimal cardiovascular system model with an extended integral based parameter identification method to track the evolution of induced pulmonary embolism in porcine data. The model accounts for ventricular interaction dynamics and is shown to predict an increase in the right ventricle expansion index and a decrease in septum volume consistent with known physiological response to pulmonary embolism. The full range of hemodynamic responses was captured with mean prediction errors of 4.1% in the pressures and 3.1% in the volumes for 6 sets of clinical data. Pulmonary resistance increased significantly with the onset of embolism in all cases, as expected, with the percentage increase ranging from 89.98% to 261.44% of the initial state. These results are an important first step towards model-based cardiac diagnosis in the Intensive Care Unit.

Assessing the influence of payment on motivations of women participating as oocyte donors

We report on the motivations of potential ovum donors entering an assisted reproduction program and discuss the potential ramifications of escalating payments to donors. From July 1995 to July 1998, recruitment of ovum donors was directed at healthy women between 21 and 34 years of age. Financial remuneration for services rendered was USD 2,500 from July 1995 through March 1998 and increased to USD 5,000 after that. Donors were screened and consented according to established SART guidelines. The demographic background of the women was similar for women paid USD 2,500 to those receiving USD 5,000. The financial motivation was greater in those receiving USD 5,000 (68%) than USD 2,500 (39%). Some form of expressed altruism was similarly present in both groups (USD 5,000 90%, and USD 2,500 91%). However, altruism expressed as the sole motivation occurred more in those receiving USD 2,500 (61%) compared to USD 5,000 (32%). Financial reimbursement has escalated for the services of ovum donors in order to maintain the increasing demand. While money has become a dominant factor motivating ovum donors, its seductive nature requires even greater attention to adequate informed consent. Young donors may be unable to adequately weigh the risks of ovarian hyperstimulation and oocyte retrieval against the monetary reward.

Surgery after downstaging of unresectable hepatic tumors with intra-arterial chemotherapy

BACKGROUND

This retrospective study was performed to assess the outcome among patients who underwent hepatic resection or tumor ablation after hepatic artery infusion (HAI) therapy down-staged previously unresectable hepatocellular carcinoma (HCC) or liver metastases from colorectal cancer (CRC).

METHODS

Between 1983 and 1998, 25 patients with HCC and 383 patients with hepatic CRC metastases were treated with HAI therapy for unresectable liver disease. We retrospectively reviewed the records of 26 (6%) of these patients who underwent subsequent surgical exploration for tumor resection or ablation.

RESULTS

At a median of 9 months (range 7-12 months) after HAI treatment, four patients (16%) with HCC underwent exploratory surgery; two underwent resection with negative margins, and the other two were given radiofrequency ablation (RFA) because of underlying cirrhosis. At a median postoperative follow-up of 16 months (range 6-48 months), all four patients were alive with no evidence of disease. At a median of 14.5 months (range 8-24 months) after HAI therapy, 22 patients with hepatic CRC metastases underwent exploratory surgery; 10 underwent resection, 6 underwent resection and RFA or cryotherapy, and 2 underwent RFA only. At a median follow-up of 17 months, 15 (83%) of the 18 patients with CRC who had received surgical treatment had developed recurrent disease; the other 3 died of other causes (1 of postoperative complications) within 7 months of the surgery. One patient in whom disease recurred underwent a second resection and was disease-free at 1 year follow-up.

CONCLUSIONS

Hepatic resection or ablation after tumor downstaging with HAI therapy is a viable option for patients with unresectable HCC. However, given the high rate of recurrence of metastases from CRC, hepatic resection or ablation after downstaging with HAI should be used with caution.

Intraoperative lower extremity compartment pressures in lithotomy-positioned patients

PURPOSE

Measurement of anterior leg compartment pressures in eight patients (16 limbs) who were positioned in the lithotomy position for prolonged periods of time while undergoing colorectal intra-abdominal surgery.

METHODS

Anterior leg compartment pressures were measured in eight patients (16 limbs) by using a slit catheter, whereas subjects were positioned in the lithotomy position for prolonged periods of time while undergoing colorectal intra-abdominal surgery.

RESULTS

Compartment pressures had minor elevations after initial lithotomy positioning, and gradually increased over time. Levels elevated to 30 mmHg at an average of five (range, 3.5 to 6) hours. The maximum recorded leg compartment pressure was 70 mmHg. The addition of Trendelenburg positioning was noted to consistently increase compartment pressures. All pressures returned to less than 10 mmHg shortly after removing the limb from the stirrups and placing the limb supine. No patients developed clinical evidence of compartment syndrome.

CONCLUSIONS

Leg anterior compartment pressures rise when limbs are placed in the lithotomy position for prolonged periods of time. The rise in pressure is increased with the addition of Trendelenburg positioning. Anterior compartment pressures reached a threshold of 30 mmHg at an average of five hours. The results of this study suggest that lithotomy positioning of the lower extremities has the potential to initiate leg compartment syndrome when the period of positioning approaches five hours. Removing the limbs from the stirrups and placing them in the supine position allows the pressure in the compartments to return to normal.

Adenovirus-mediated expression of a ribozyme to c-myb mRNA inhibits smooth muscle cell proliferation and neointima formation in vivo

Smooth muscle cell (SMC) proliferation is an important component of restenosis in response to injury after balloon angioplasty. Inhibition of proliferation in vivo can limit neointima hyperplasia in animal models of restenosis. Ribozymes against c-myb mRNA have been shown to be effective inhibitors of SMC proliferation in vitro. The effectiveness of adenovirus as a gene therapy vector in animal models of restenosis is well documented. In order to test the utility of ribozymes to inhibit SMC proliferation by a gene therapy approach, recombinant adenovirus expressing ribozymes against c-myb mRNA was generated and tested both in vitro and in vivo. This adenovirus ribozyme vector is shown to inhibit SMC proliferation in culture and neointima formation in a rat carotid artery balloon injury model of restenosis.

Flexion and traction effect on C5-C6 foraminal space

OBJECTIVE

To determine the effects of cervical flexion and traction on foraminal volume and isthmus area at the C5-C6 foraminal space in cadavers.

DESIGN

This study evaluated the foraminal space at C5-C6 in cadaver specimens during flexion and traction of the cervical spine.

SETTING

An orthopedic biomechanics laboratory and department of radiology of a university medical center.

PATIENTS OR OTHER PARTICIPANTS

Nine cadaver cervical spines, C1 through T3, were used in the study. Superficial tissues were dissected, preserving the ligaments.

INTERVENTIONS

Proximal and distal portions of the cadaver spines were potted using bone cement. Spines were mounted and imaged with computed tomography in neutral position, 15 degrees of flexion, and maximum flexion with and without 25lbs of axial traction.

MAIN OUTCOME MEASURES

The areas and volumes of the foramen were measured and calculated.

RESULTS

Flexion alone significantly increased the foraminal volume and isthmus area at C5-C6. Traction resulted in little additional change.

CONCLUSIONS

For cervical spines with mild to moderate degenerative changes at C5-C6, cervical flexion with or without traction produces significant increases in foraminal volume and area at the foraminal isthmus.

Value-based formulas for purchasing. Pursuing value in Medicaid managed care: access to care and enrollee information management

Medicaid and other publicly funded health coverage programs face special challenges in managed care purchasing. This article discusses two of those challenges based on the state of Minnesota's experience: how to develop, evaluate, and communicate access to care; and how to manage the transfer of enrollee eligibility and health status information.

Phase II trial of hepatic arterial infusion of fluorouracil and recombinant human interferon alfa-2b for liver metastases of colorectal cancer refractory to systemic fluorouracil and leucovorin

PURPOSE

To determine the toxicity, response rate, and survival in patients treated with hepatic arterial infusion (HAI) of fluorouracil (5-FU) plus recombinant human interferon alfa-2b (rIFN-alpha 2b) (Intron-A; Schering-Plough, Inc, Kenilworth, NJ) for colorectal carcinoma (CRC) liver metastases refractory to systemic 5-FU plus leucovorin (LCV).

PATIENTS AND METHODS

Forty-eight patients were given a 6-hour HAI of rIFN-alpha 2b 5 MU/m2 followed by an 18-hour HAI of 5-FU, 1,500 mg/m2 daily for 5 days. Twenty-nine patients were treated through percutaneously placed catheters and 19 through implantable infusion pumps (Shiley Infusaid Inc, Noorwood, MA). Treatment cycles were repeated every 28 to 35 days.

RESULTS

There were three (6.6%) complete remissions (CRs) and 12 (26.6%) partial remissions (PRs), for a CR plus PR rate of 33.3% among 45 assessable patients (95% confidence interval [CI], 20% to 49%). The median response duration was 7 months, while median survival duration was 15 months. Grade 3 to 4 treatment-related toxic effects included mucositis (40%), neutropenia (42%), and thrombocytopenia (12%). No hepatobiliary toxicity was encountered in any of the patients. Treatment was discontinued because of progressive liver disease in 23 patients and extrahepatic progression in 16, while six patients continue treatment through an infusaid pump.

CONCLUSION

HAI of 5-FU plus rIFN-alpha 2b is well tolerated, devoid of hepatobiliary toxicity, and can produce a response rate of 33.3% among patients refractory to bolus intravenous (IV) 5-FU plus LCV. The lack of hepatobiliary toxicity may permit salvage HAI with floxuridine (FUDR) in patients whose liver tumors fail to respond to HAI of 5-FU plus rIFN-alpha 2b. Because diarrhea was not a common side effect of HAI of 5-FU plus rIFN-alpha 2b, it would be of interest to investigate whether alternating HAI of 5-FU and rIFN-alpha 2b with systemic irinotecan (CPT-11) will decrease the incidence of both hepatic and extrahepatic disease progression.

Judgements and processes in care decisions in acute medical and surgical wards

The decisions which health care professionals make are the basis of treatment and care given. In order to evaluate effective care it seems logical to suggests that an awareness of the decisions which health care professionals make and how they make them is needed. This study examines the processes nurses use when making decisions about the health care needs of acutely ill patients. In stage one, 104 qualified nurses were interviewed to identify how they decide health care needs. In stage two, a 'think aloud' technique was used with patient simulations to obtain verbal protocols from a further 55 qualified nurses to identify the information strategies they used when making these decisions. The results suggest that nurses base their health care decisions mainly on their assessment of qualitative patient states or conditions. Initial indications are that the processes used differ from those characterized in the diagnostic reasoning model, with the context in which decisions are made being an important influence together with nurses' experience. It is suggested that, in order to develop effective predictive models and clinical guidelines which aid decision making, more research into the nature of health care professionals' decision making is carried out.

Overview and critique of judgement and decision making in health care: social and procedural dimensions

This paper presents an outline of the scope for the application of decision theory to health care. Firstly, the main approaches to and assumptions of decision theory are discussed. Secondly, health care decision making is reviewed. It is noted that decision theory can be applied to either the health care professional or to the lay person. Applications of decision theory to clinical practice, to the management of care and to resourcing are considered. Thirdly, some areas which would repay further research are identified. These include social processes in individual and group decision making, the temporal distribution of outcomes and the development of techniques capable of dealing with the complex and dynamic features of decisions. On the basis of the foregoing, some conclusions are drawn.

Comparison between the Health Belief Model and Subjective Expected Utility Theory: predicting incontinence prevention behaviour in post-partum women

A small-scale study was undertaken to test the relative predictive power of the Health Belief Model and Subjective Expected Utility Theory for the uptake of a behaviour (pelvic floor exercises) to reduce post-partum urinary incontinence in primigravida females. A structured questionnaire was used to gather data relevant to both models from a sample antenatal and postnatal primigravida women. Questions examined the perceived probability of becoming incontinent, the perceived (dis)utility of incontinence, the perceived probability of pelvic floor exercises preventing future urinary incontinence, the costs and benefits of performing pelvic floor exercises and sources of information and knowledge about incontinence. Multiple regression analysis focused on whether or not respondents intended to perform pelvic floor exercises and the factors influencing their decisions. Aggregated data were analysed to compare the Health Belief Model and Subjective Expected Utility Theory directly.

NMR studies of muscle glycogen synthesis in insulin-resistant offspring of parents with non-insulin-dependent diabetes mellitus immediately after glycogen-depleting exercise

To examine the impact of insulin resistance on the insulin-dependent and insulin-independent portions of muscle glycogen synthesis during recovery from exercise, we studied eight young, lean, normoglycemic insulin-resistant (IR) offspring of individuals with non-insulin-dependent diabetes mellitus and eight age-weight matched control (CON) subjects after plantar flexion exercise that lowered muscle glycogen to approximately 25% of resting concentration. After approximately 20 min of exercise, intramuscular glucose 6-phosphate and glycogen were simultaneously monitored with 31P and 13C NMR spectroscopies. The postexercise rate of glycogen resynthesis was nonlinear. Glycogen synthesis rates during the initial insulin independent portion (0-1 hr of recovery) were similar in the two groups (IR, 15.5 +/- 1.3 mM/hr and CON, 15.8 +/- 1.7 mM/hr); however, over the next 4 hr, insulin-dependent glycogen synthesis was significantly reduced in the IR group [IR, 0.1 +/- 0.5 mM/hr and CON, 2.9 +/- 0.2 mM/hr; (P < or = 0.001)]. After exercise there was an initial rise in glucose 6-phosphate concentrations that returned to baseline after the first hour of recovery in both groups. In summary, we found that following muscle glycogen-depleting exercise, IR offspring of parents with non-insulin-dependent diabetes mellitus had (i) normal rates of muscle glycogen synthesis during the insulin-independent phase of recovery from exercise and (ii) severely diminished rates of muscle glycogen synthesis during the subsequent recovery period (2-5 hr), which has previously been shown to be insulin-dependent in normal CON subjects. These data provide evidence that exercise and insulin stimulate muscle glycogen synthesis in humans by different mechanisms and that in the IR subjects the early response to stimulation by exercise is normal.