Breast Cancer Screening and BI-RADS Scoring Trends Before and During the COVID-19 Pandemic in an Academic Safety-Net Hospital.

BACKGROUND: Little is known about how the COVID-19 pandemic affected screening mammography rates and Breast Imaging Reporting and Data Systems (BI-RADS) categorizations within populations facing social and economic inequities. Our study seeks to compare trends in breast cancer screening and BI-RADS assessments in an academic safety-net patient population before and during the COVID-19 pandemic. PATIENTS AND METHODS: Our single-center retrospective study evaluated women ≥ 18 years old with no known breast cancer diagnosis who received breast cancer screening from March 2019-September 2020. The screening BI-RADS score, completion of recommended diagnostic imaging, and diagnostic BI-RADS scores were compared between the pre-COVID-19 era (from 1 March 2019 to 19 March 2020) and COVID-19 era (from 20 March 2020 to 30 September 2020). RESULTS: Among the 11,798 patients identified, screened patients were younger (median age 57 versus 59 years, p < 0.001) and more likely covered by private insurance (35.9% versus 32.3%, p < 0.001) during the COVID-19 era compared with the pre-COVID-19 era. During the pandemic, there was an increase in screening mammograms categorized as BI-RADS 0 compared with the pre-COVID-19 era (20% versus 14.5%, p < 0.0001). There was no statistically significant difference in rates of completion of diagnostic imaging (81.6% versus 85.4%, p = 0.764) or assignment of suspicious BI-RADS scores (BI-RADS 4-5; 79.9% versus 80.8%, p = 0.762) between the two eras. CONCLUSIONS: Although more patients were recommended to undergo diagnostic imaging during the pandemic, there were no significant differences in race, completion of diagnostic imaging, or proportions of mammograms categorized as suspicious between the two time periods. These findings likely reflect efforts to maintain equitable care among diverse racial groups served by our safety-net hospital.

Assessing breast cancer-related lymphedema screening and treatment gaps in a safety-net hospital.

BACKGROUND AND OBJECTIVES: We evaluated the unmet breast cancer-related lymphedema (BCRL) treatment and education needs at New England's largest safety-net hospital serving a diverse population by assessing prevalence, risk factors, and treatment. METHODS: This was a retrospective cohort study examining breast cancer surgery patients from September 2016 to September 2021. The primary outcome was BCRL diagnosis. Secondary outcomes included BCRL risk factors, and physical and occupational therapy (PT/OT) referral frequency and completion. RESULTS: Of 639 patients, 17% of patients had documented BCRL, which was significantly associated with axillary lymph node dissection (ALND). There were no racial, insurance, breast radiation, or BMI category differences between patients with and without a BCRL diagnosis. Of those with BCRL, 58% received a PT/OT referral, and 56% completed their referral. There were no racial, insurance, or BMI category differences between those who received a PT/OT referral and those who did not. CONCLUSION: In our high-risk population, rates of documented BCRL were higher than expected, approaching rates of ALND, despite the majority undergoing sentinel lymph node biopsy (SLNB). PT/OT referral and completion rates were low, concerning for an unmet BCRL treatment and education need. No disparities in care delivery were seen, but a program that addresses treatment gaps and ensures accessible and patient-centered BCRL care is urgently needed.

Assessing Time to Removal of Tunneled Dialysis Catheters after Arteriovenous Access Creation.

BACKGROUND: Tunneled dialysis catheters (TDCs) are a temporary bridge until definitive arteriovenous (AV) access is established. Our objective was to evaluate the time to TDC removal in patients who underwent AV access creations with TDCs already in place. METHODS: A single-center analysis of all AV access creations in patients with TDCs was performed (2014-2020). Primary outcome was time to TDC removal after access creation. RESULTS: There were 364 AV access creations with TDCs in place. The average age was 58 years, 44% of patients were female, and 64% were Black. The median time to TDC removal was 113 days (range, 22-931 days) with 71.4% having a TDC >90 days after access creation. Patients with TDC >90 days were often older (60 vs. 54.7), had hypertension (98.1% vs. 93.3%), were diabetic (65.4% vs. 47.1%), and had longer average time to maturation (107.1 vs. 55.4 days, P < 0.001) and first access (114 vs. 59.4 days, P < 0.001). Multivariable analysis showed that older age was associated with prolonged TDC placement (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05, P = 0.005) and prosthetic graft use was associated with shorter TDC indwelling time (OR 0.09, 95% CI 0.04-0.23, P ≤ 0.001). Kaplan-Meier analysis showed that 87% of TDCs were removed at 1 year. CONCLUSIONS: The majority of patients with TDCs who underwent AV access creation had prolonged TDC placement. Prosthetic graft use was associated with shorter catheter times. Close follow-up after access placement, improving maturation times, and access type selection should be considered to shortened TDC times.

Group B Streptococcus Infection and Obstetric Hemorrhage Risk.

OBJECTIVE: To elucidate the association between GBS infection and maternal risk for obstetric hemorrhage (OBH) and OBH-related morbidities (OBH-M). METHODS: This was a retrospective cohort study of all deliveries with a documented GBS status at a single large academic medical center from 2018 to 2019. GBS status was determined by either urine culture or rectovaginal culture collected during the antepartum period. The primary outcomes were quantitative blood loss (QBL), OBH, and a composite of OBH-M. Secondary outcomes were individual components of the OBH-M composite and frequency of hemorrhage-related interventions utilized intrapartum and postpartum. A stratified analysis was conducted examining only patients who were diagnosed intrapartum with an intrapartum intraamniotic infection (III). RESULTS: Of 4679 pregnant individuals who delivered a live infant between January 1, 2018 and January 1,2019 with a documented GBS status, 1,487 were identified as GBS positive (+) and 3192 were identified as GBS negative (-). The GBS + group did not have significantly higher QBL (p = 0.29) or rate of OBH (p = 0.35). There were no significant differences by GBS status in OBH morbidity (p = 0.79) or its individual components or frequency of individual pharmacologic or non-pharmacologic OBHrelated interventions. There were also no significant differences by GBS status among patients with an III. CONCLUSIONS FOR PRACTICE: GBS infection at the time of delivery was not associated with increased risk for OBH or OBH-M. Further research is needed to further explore the relationship between peripartum infections and OBH risk.

Pre-Pandemic and Recent Oral and Medical Health Care Utilization among Young American Indian Children and Their Caregivers.

Children from diverse ethnic groups are at significantly increased risk for dental caries. In particular, American Indian (AI) children have the highest incidence of detal caries of any ethnic group. The COVID-19 pandemic dramatically restricted health care access, including preventive oral health care. Given this context, it is unclear whether or not preventive oral health care for AI children has resumed since lockdown. To address this question, we surveyed adult AI caregivers (N = 152) of children aged 0-5 years, assessing recent (12-month) and pre-COVID (for caregivers of children aged 3-5 years) preventive oral and medical health services. We also examined medical health care access and utilization among caregivers. Among children aged 3-5 years old, both pre-pandemic and past year medical care utilization were generally high (80 and 90%, respectively) as was any oral health care utilization (64 & 78%, respectively). Oral health check-ups were more common over the last year (62%) compared to pre-COVID (44%). Recent health care utilization among children 1-5 years old in this sample were generally comparable to national estimates, except for higher reported preventive medical care (99% vs. 87.6%, respectively) and higher preventive oral care (96% vs. 59.6%, respectively). More caregivers reported delaying or foregoing needed health care due to COVID (28-38%) versus due to cost (8-17%). In this survey of AI caregivers, recent child preventive health care utilization was high, and changes in utilization following the lockdown phases of the pandemic were comparable for oral and medical health care.

Association between duration of intrapartum oxytocin exposure and obstetric hemorrhage.

PURPOSE: Prolonged duration of intrapartum oxytocin exposure is included as a risk factor within widely adopted obstetric hemorrhage risk stratification tools. However, the duration of exposure that confers increased risk is poorly understood. This study aimed to assess the association between duration of intrapartum oxytocin exposure and obstetric blood loss, as measured by quantitative blood loss, and hemorrhage-related maternal morbidity. METHODS: This was a retrospective cohort study of all deliveries from 2018 to 2019 at a single medical center. We included patients who had received any intrapartum oxytocin, and we categorized them into 1 of 5 groups: > 0-2, ≥ 2-4, ≥ 4-6, ≥ 6-12, and ≥ 12 h of intrapartum oxytocin exposure. The primary outcomes were mean quantitative blood loss, proportion with obstetric hemorrhage (defined as quantitative blood loss ≥ 1000 mL), and proportion with obstetric hemorrhage-related morbidity, a composite of hemorrhage-related morbidity outcomes. Secondary outcomes were hemorrhage-related pharmacologic and procedural interventions. A stratified analysis was also conducted to examine primary and secondary outcomes by delivery mode. RESULTS: Of 5332 deliveries between January 1, 2018 and December 31, 2019 at our institution, 2232 (41.9%) utilized oxytocin for induction or augmentation. 326 (14.6%) had exposure of > 0-2 h, 295 (13.2%) ≥ 2-4 h, 298 (13.4%) ≥ 4-6 h, 562 (25.2%) ≥ 6-12 h, and 751 (33.6%) ≥ 12 h. Across all deliveries, there was higher mean quantitative blood loss (p < 0.01) as well as increased odds of obstetric hemorrhage (adjusted odds ratio [aOR] 1.52, 95% confidence interval [CI] 1.21-1.91) for those with ≥ 12 h of oxytocin compared to all groups between > 0-12 h of exposure. In our stratified analysis, ≥ 12 h of oxytocin exposure was associated with higher mean quantitative blood loss (p = 0.04) and odds of obstetric hemorrhage in vaginal deliveries (aOR 1.47, 95% CI: 1.03-2.11), though not in cesarean deliveries (aOR 1.16, 95% CI 0.82-1.62). There were no differences in proportion with obstetric hemorrhage-related morbidity across all deliveries (p = 0.40) or in the stratified analysis. CONCLUSION: Intrapartum oxytocin exposure of ≥ 12 h was associated with increased quantitative blood loss and odds of obstetric hemorrhage in vaginal, but not cesarean, deliveries.

Metabolic Remodeling Promotes Cardiac Hypertrophy by Directing Glucose to Aspartate Biosynthesis.

RATIONALE: Hypertrophied hearts switch from mainly using fatty acids (FAs) to an increased reliance on glucose for energy production. It has been shown that preserving FA oxidation (FAO) prevents the pathological shift of substrate preference, preserves cardiac function and energetics, and reduces cardiomyocyte hypertrophy during cardiac stresses. However, it remains elusive whether substrate metabolism regulates cardiomyocyte hypertrophy directly or via a secondary effect of improving cardiac energetics. OBJECTIVE: The goal of this study was to determine the mechanisms of how preservation of FAO prevents the hypertrophic growth of cardiomyocytes. METHODS AND RESULTS: We cultured adult rat cardiomyocytes in a medium containing glucose and mixed-chain FAs and induced pathological hypertrophy by phenylephrine. Phenylephrine-induced hypertrophy was associated with increased glucose consumption and higher intracellular aspartate levels, resulting in increased synthesis of nucleotides, RNA, and proteins. These changes could be prevented by increasing FAO via deletion of ACC2 (acetyl-CoA-carboxylase 2) in phenylephrine-stimulated cardiomyocytes and in pressure overload-induced cardiac hypertrophy in vivo. Furthermore, aspartate supplementation was sufficient to reverse the antihypertrophic effect of ACC2 deletion demonstrating a causal role of elevated aspartate level in cardiomyocyte hypertrophy. 15N and 13C stable isotope tracing revealed that glucose but not glutamine contributed to increased biosynthesis of aspartate, which supplied nitrogen for nucleotide synthesis during cardiomyocyte hypertrophy. CONCLUSIONS: Our data show that increased glucose consumption is required to support aspartate synthesis that drives the increase of biomass during cardiac hypertrophy. Preservation of FAO prevents the shift of metabolic flux into the anabolic pathway and maintains catabolic metabolism for energy production, thus preventing cardiac hypertrophy and improving myocardial energetics.

Intrapartum Risk Factors and Prediction of Obstetric Hemorrhage-Related Morbidity.

OBJECTIVE: The aim of this study was to assess whether inclusion of intrapartum risk factors improves our obstetric hemorrhage risk stratification tool in predicting obstetric hemorrhage, transfusion, and related severe morbidity. STUDY DESIGN: This is a retrospective cohort study using all live deliveries at a single institution over a 2-year period (n = 5,332). Obstetric hemorrhage risk factors, hemorrhage burden, and severe maternal morbidity index outcomes were assessed through chart abstraction. Hemorrhage risk was assessed at (1) "time of admission" through chart abstraction and (2) "predelivery" by calculation after inclusion of all abstracted intrapartum risk factors. Admission high risk was compared with predelivery high risk for sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio in predicting obstetric hemorrhage, obstetric hemorrhage requiring transfusion, and obstetric hemorrhage-related severe morbidity. Significance levels were calculated using descriptive statistical methods including chi-squared tests and McNemar's tests. RESULTS: The sensitivities of the risk assessment tool using admission risk classification for high-risk patients is 25% for obstetric hemorrhage, 37% for obstetric hemorrhage requiring transfusion, and 22% for obstetric hemorrhage-related severe morbidity. After intrapartum factor inclusion, the sensitivities increase to 55% for obstetric hemorrhage, 59% for obstetric hemorrhage requiring transfusion, and 47% for obstetric hemorrhage-related severe morbidity. This "predelivery" risk assessment is significantly more sensitive across all three end points (p < 0.001 for all three outcomes). While the positive likelihood ratios for obstetric hemorrhage are equal on admission and predelivery (2.10 on admission and predelivery), they increase after intrapartum factor inclusion for obstetric hemorrhage requiring transfusion and obstetric hemorrhage-related severe morbidity (on admission, 2.74 and 1.6, respectively, and predelivery: 4.57 and 3.58, respectively). CONCLUSION: Inclusion of intrapartum risk factors increases the accuracy of this obstetric hemorrhage risk stratification tool in predicting patients requiring hemorrhage management with transfusion and obstetric hemorrhage-related severe morbidity. KEY POINTS: · There are little data to validate intrapartum hemorrhage risk reassessment.. · Including intrapartum factors improves risk stratification for transfusion and related morbidity.. · Future research should clinically validate risk reassessment in the intrapartum period..

Increasing fatty acid oxidation elicits a sex-dependent response in failing mouse hearts.

BACKGROUND: Reduced fatty acid oxidation (FAO) is a hallmark of metabolic remodeling in heart failure. Enhancing mitochondrial long-chain fatty acid uptake by Acetyl-CoA carboxylase 2 (ACC2) deletion increases FAO and prevents cardiac dysfunction during chronic stresses, but therapeutic efficacy of this approach has not been determined. METHODS: Male and female ACC2 f/f-MCM (ACC2KO) and their respective littermate controls were subjected to chronic pressure overload by TAC surgery. Tamoxifen injection 3 weeks after TAC induced ACC2 deletion and increased FAO in ACC2KO mice with pathological hypertrophy. RESULTS: ACC2 deletion in mice with pre-existing cardiac pathology promoted FAO in female and male hearts, but improved cardiac function only in female mice. In males, pressure overload caused a downregulation in the mitochondrial oxidative function. Stimulating FAO by ACC2 deletion caused unproductive acyl-carnitine accumulation, which failed to improve cardiac energetics. In contrast, mitochondrial oxidative capacity was sustained in female pressure overloaded hearts and ACC2 deletion improved myocardial energetics. Mechanistically, we revealed a sex-dependent regulation of PPARα signaling pathway in heart failure, which accounted for the differential response to ACC2 deletion. CONCLUSION: Metabolic remodeling in the failing heart is sex-dependent which could determine the response to metabolic intervention. The findings suggest that both mitochondrial oxidative capacity and substrate preference should be considered for metabolic therapy of heart failure.

Convenience and comfort: reasons reported for using drugs alone among clients of harm reduction sites in British Columbia, Canada.

BACKGROUND: North American communities are severely impacted by the overdose crisis, particularly in British Columbia (BC), which has the highest toxic drug overdose death rate in Canada. Most fatal overdoses in BC occurred among individuals using alone and in private residences. This study aimed to assess prevalence and reasons for using drugs alone among people accessing harm reduction services in BC. METHODS: We recruited harm reduction supply distribution site clients from 22 communities across BC. Descriptive statistics and multivariable logistic regression were used to describe factors associated with using alone. Thematic analysis of free-text responses providing reasons for using alone were grouped with survey data and additional themes identified. RESULTS: Overall, 75.8% (n = 314) of the study sample (N = 414) reported using drugs alone within the last week. Those that reported using alone did not differ from those that did not by gender, age, urbanicity, or preferred drug use method. Among those that used alone, 73.2% (n = 230) used opioids, 76.8% (n = 241) used crystal meth, 41.4% (n = 130) used crack/cocaine, and 44.6% (n = 140) used alcohol in the past week. Polysubstance use involving stimulants, opioids, and/or benzodiazepines was reported by 68.5% (n = 215) of those that used alone. Additionally, 22.9% (n = 72) of those that used alone had experienced an opioid and/or stimulant overdose in the past 6 months. In a multivariable logistic regression model, having no regular housing and past week crack/cocaine use were associated with using alone (adjusted odds ratio (AOR): 2.27; 95% CI 1.20-4.27 and AOR: 2.10; 95% CI 1.15-3.82, respectively). The most common reason reported for using alone was convenience and comfort of using alone (44.3%). Additional reasons included: stigma/hiding drug use (14.0%); having no one around (11.7%); safety (9.6%); and not wanting to share drugs with others (8.6%). CONCLUSIONS: Using drugs alone, particularly for convenience and comfort, is ubiquitous among people accessing harm reduction services. Overdose prevention measures that go beyond individual behaviour changes, including providing a safer supply of drugs and eliminating stigma, are paramount to mitigate harms. These interventions are especially necessary as emergence of coronavirus disease may further exacerbate unpredictability of illicit drug content and overdose risk.

Function of inhibitor of Bruton's tyrosine kinase isoform α (IBTKα) in nonalcoholic steatohepatitis links autophagy and the unfolded protein response.

Nonalcoholic fatty liver disease (steatosis) is the most prevalent liver disease in the Western world. One of the advanced pathologies is nonalcoholic steatohepatitis (NASH), which is associated with induction of the unfolded protein response (UPR) and disruption of autophagic flux. However, the mechanisms by which these processes contribute to the pathogenesis of human diseases are unclear. Herein, we identify the α isoform of the inhibitor of Bruton's tyrosine kinase (IBTKα) as a member of the UPR, whose expression is preferentially translated during endoplasmic reticulum (ER) stress. We found that IBTKα is located in the ER and associates with proteins LC3b, SEC16A, and SEC31A and plays a previously unrecognized role in phagophore initiation from ER exit sites. Depletion of IBTKα helps prevent accumulation of autophagosome intermediates stemming from exposure to saturated free fatty acids and rescues hepatocytes from death. Of note, induction of IBTKα and the UPR, along with inhibition of autophagic flux, was associated with progression from steatosis to NASH in liver biopsies. These results indicate a function for IBTKα in NASH that links autophagy with activation of the UPR.

Cobalamin Deficiency Results in Increased Production of Formate Secondary to Decreased Mitochondrial Oxidation of One-Carbon Units in Rats.

Background: Formate is produced in mitochondria via the catabolism of serine, glycine, dimethylglycine, and sarcosine. Formate produced by mitochondria may be incorporated into the cytosolic folate pool where it can be used for important biosynthetic reactions. Previous studies from our lab have shown that cobalamin deficiency results in increased plasma formate concentrations. Objective: Our goal was to determine the basis for elevated formate in vitamin B-12 deficiency. Methods: Male Sprague Dawley rats were randomly assigned to consume either a cobalamin-replete (50 µg cobalamin/kg diet) or -deficient (no added cobalamin) diet for 6 wk. Formate production was measured in vivo and in isolated liver mitochondria from a variety of one-carbon precursors. We also measured the oxidation of [3-14C]-l-serine to 14CO2 in isolated rat liver mitochondria and the expression of hepatic genes involved in one-carbon unit and formate metabolism. Results: Cobalamin-deficient rats produce formate at a rate 55% higher than that of replete rats. Formate production from serine was increased by 60% and from dimethylglycine and sarcosine by ∼200% in liver mitochondria isolated from cobalamin-deficient rats compared with cobalamin-replete rats. There was a 26% decrease in the 14CO2 produced by mitochondria from cobalamin-deficient rats. Gene expression analysis showed that 10-formyltetrahydrofolate dehydrogenase-cytosolic (Aldh1l1) and mitochondrial (Aldh1l2) expression were decreased by 40% and 60%, respectively, compared to control, while 10-formyltetrahydrofolate synthetase, mitochondrial, monofunctional (Mthfd1l) expression was unchanged. Conclusion: We propose that a bifurcation in mitochondrial one-carbon metabolism is a key control mechanism in determining the fate of one-carbon units, to formate or CO2. During cobalamin deficiency in rats the disposition of 10-formyl-tetrahydrofolate carbon is shifted in favor of formate production. This may represent a mechanism to generate more one-carbon units for the replenishment of the S-adenosylmethionine pool which is depleted in this condition.

Upstream Open Reading Frames Differentially Regulate Gene-specific Translation in the Integrated Stress Response.

Translation regulation largely occurs during initiation, which features ribosome assembly onto mRNAs and selection of the translation start site. Short, upstream ORFs (uORFs) located in the 5'-leader of the mRNA can be selected for translation. Multiple transcripts associated with stress amelioration are preferentially translated through uORF-mediated mechanisms during activation of the integrated stress response (ISR) in which phosphorylation of the α subunit of eIF2 results in a coincident global reduction in translation initiation. This review presents key features of uORFs that serve to optimize translational control that is essential for regulation of cell fate in response to environmental stresses.

Translation Regulation of the Glutamyl-prolyl-tRNA Synthetase Gene EPRS through Bypass of Upstream Open Reading Frames with Noncanonical Initiation Codons.

In the integrated stress response, phosphorylation of eIF2α (eIF2α-P) reduces protein synthesis while concomitantly promoting preferential translation of specific transcripts associated with stress adaptation. Translation of the glutamyl-prolyl-tRNA synthetase gene EPRS is enhanced in response to eIF2α-P. To identify the underlying mechanism of translation control, we employed biochemical approaches to determine the regulatory features by which upstream ORFs (uORFs) direct downstream translation control and expression of the EPRS coding region. Our findings reveal that translation of two inhibitory uORFs encoded by noncanonical CUG and UUG initiation codons in the EPRS mRNA 5'-leader serve to dampen levels of translation initiation at the EPRS coding region. By a mechanism suggested to involve increased translation initiation stringency during stress-induced eIF2α-P, we observed facilitated ribosome bypass of these uORFs, allowing for increased translation of the EPRS coding region. Importantly, EPRS protein expression is enhanced through this preferential translation mechanism in response to multiple known activators of eIF2α-P and likely serves to facilitate stress adaptation in response to a variety of cellular stresses. The rules presented here for the regulated ribosome bypass of noncanonical initiation codons in the EPRS 5'-leader add complexity into the nature of uORF-mediated translation control mechanisms during eIF2α-P and additionally illustrate the roles that previously unexamined uORFs with noncanonical initiation codons can play in modulating gene expression.

Nuclear Matrix Protein 4 Is a Novel Regulator of Ribosome Biogenesis and Controls the Unfolded Protein Response via Repression of Gadd34 Expression.

The unfolded protein response (UPR) maintains protein homeostasis by governing the processing capacity of the endoplasmic reticulum (ER) to manage ER client loads; however, key regulators within the UPR remain to be identified. Activation of the UPR sensor PERK (EIFAK3/PEK) results in the phosphorylation of the α subunit of eIF2 (eIF2α-P), which represses translation initiation and reduces influx of newly synthesized proteins into the overloaded ER. As part of this adaptive response, eIF2α-P also induces a feedback mechanism through enhanced transcriptional and translational expression of Gadd34 (Ppp1r15A),which targets type 1 protein phosphatase for dephosphorylation of eIF2α-P to restore protein synthesis. Here we describe a novel mechanism by which Gadd34 expression is regulated through the activity of the zinc finger transcription factor NMP4 (ZNF384, CIZ). NMP4 functions to suppress bone anabolism, and we suggest that this occurs due to decreased protein synthesis of factors involved in bone formation through NMP4-mediated dampening of Gadd34 and c-Myc expression. Loss of Nmp4 resulted in an increase in c-Myc and Gadd34 expression that facilitated enhanced ribosome biogenesis and global protein synthesis. Importantly, protein synthesis was sustained during pharmacological induction of the UPR through a mechanism suggested to involve GADD34-mediated dephosphorylation of eIF2α-P. Sustained protein synthesis sensitized cells to pharmacological induction of the UPR, and the observed decrease in cell viability was restored upon inhibition of GADD34 activity. We conclude that NMP4 is a key regulator of ribosome biogenesis and the UPR, which together play a central role in determining cell viability during endoplasmic reticulum stress.

Ribosome Elongation Stall Directs Gene-specific Translation in the Integrated Stress Response.

Upon exposure to environmental stress, phosphorylation of the α subunit of eIF2 (eIF2α-P) represses global protein synthesis, coincident with preferential translation of gene transcripts that mitigate stress damage or alternatively trigger apoptosis. Because there are multiple mammalian eIF2 kinases, each responding to different stress arrangements, this translational control scheme is referred to as the integrated stress response (ISR). Included among the preferentially translated mRNAs induced by eIF2α-P is that encoding the transcription factor CHOP (DDIT3/GADD153). Enhanced levels of CHOP promote cell death when ISR signaling is insufficient to restore cell homeostasis. Preferential translation of CHOP mRNA occurs by a mechanism involving ribosome bypass of an inhibitory upstream ORF (uORF) situated in the 5'-leader of the CHOP mRNA. In this study, we used biochemical and genetic approaches to define the inhibitory features of the CHOP uORF and the biological consequences of loss of the CHOP uORF on CHOP expression during stress. We discovered that specific sequences within the CHOP uORF serve to stall elongating ribosomes and prevent ribosome reinitiation at the downstream CHOP coding sequence. As a consequence, deletion of the CHOP uORF substantially increases the levels and modifies the pattern of induction of CHOP expression in the ISR. Enhanced CHOP expression leads to increased expression of key CHOP target genes, culminating in increased cell death in response to stress.

Use of cell phones and computers for health promotion and tobacco cessation by American Indian college students in Montana.

INTRODUCTION: Cell phones and personal computers have become popular mechanisms for delivering and monitoring health information and education, including the delivery of tobacco cessation education and support. Tobacco smoking is prevalent among American Indians (AIs) and Alaska Natives (ANs), with 26% AI/AN adult men smoking compared to 19% of Caucasian adult males and 22% of African American adult males. Smoking is even more prevalent in Northern Plains AI populations, with 42% of men and women reporting current smoking. The literature on the availability and use of cell phones and computers, or the acceptability of use in health promotion among AIs and ANs, is scant. The authors report findings from a survey of AI students regarding their cell phone and computer access and use. The survey was conducted to inform the development and implementation of a text messaging smoking cessation intervention modeled on a program developed and used in Australia. METHODS: A 22-item paper and pencil survey was administered to students at tribal colleges in rural Montana. The survey questions included cell phone ownership and access to service, use of cell phones and computers for health information, demographics, tobacco use habits, and interest in an intervention study. The study was reviewed and determined exempt by the institutional review boards at the tribal colleges and the lead research university. The study was conducted by researchers at the tribal colleges. Survey respondents received $10 when the survey was completed and returned. Data analysis was performed with the Statistical Package for the Social Sciences. RESULTS: Among 153 AI respondents, the mean age was 29 years, range was 18-64 years. Overall, 40% reported smoking cigarettes with a mean age of 16 years at initiation. A total of 131 participants (86%) had cell phones and, of those, 122 (93%) had unlimited text messaging. A total of 104 (68%) had smart phones (with internet access), although 40% of those with smart phones reported that internet access on their phone was very slow or location limited. A total of 146 (95%) participants reported having access to a computer, although 32% of those did not have daily access. Students aged less than 23 years were more likely to have cell phones with internet access. Cell phone ownership differed by site (93% vs 77%, p=0.007). About 60% of the respondents who smoked indicated interest in participating in the intervention study. CONCLUSIONS: This study revealed that AI tribal college students in the rural communities surveyed had less cell phone, smart phone, and computer and internet access than that reported for undergraduate college students elsewhere in the USA. Research efforts and public health interventions must be culturally appropriate and technologically viable, therefore access to and acceptability of mobile technology must be evaluated when planning and implementing interventions for rural and other marginalized populations. The findings from this study contribute to the literature regarding the access to and acceptability of mobile technology for health promotion among AI/AN college students in rural and remote areas, and helped introduce the proposed study to the community and solicited useful data regarding tobacco prevalence and interest in tobacco research in the target population.

Ribosome Reinitiation Directs Gene-specific Translation and Regulates the Integrated Stress Response.

In the integrated stress response, phosphorylation of eIF2α (eIF2α-P) reduces protein synthesis to conserve resources and facilitate preferential translation of transcripts that promote stress adaptation. Preferentially translated GADD34 (PPP1R15A) and constitutively expressed CReP (PPP1R15B) function to dephosphorylate eIF2α-P and restore protein synthesis. The 5'-leaders of GADD34 and CReP contain two upstream ORFs (uORFs). Using biochemical and genetic approaches we show that features of these uORFs are central for their differential expression. In the absence of stress, translation of an inhibitory uORF in GADD34 acts as a barrier that prevents reinitiation at the GADD34 coding region. Enhanced eIF2α-P during stress directs ribosome bypass of the uORF, facilitating translation of the GADD34 coding region. CReP expression occurs independent of eIF2α-P via an uORF that allows for translation reinitiation at the CReP coding region independent of stress. Importantly, alterations in the GADD34 uORF affect the status of eIF2α-P, translational control, and cell adaptation to stress. These results show that properties of uORFs that permit ribosome reinitiation are critical for directing gene-specific translational control in the integrated stress response.

In vivo kinetics of formate metabolism in folate-deficient and folate-replete rats.

It is now established that the mitochondrial production of formate is a major process in the endogenous generation of folate-linked one-carbon groups. We have developed an in vivo approach involving the constant infusion of [(13)C]formate until isotopic steady state is attained to measure the rate of endogenous formate production in rats fed on either a folate-replete or folate-deficient diet. Formate was produced at a rate of 76 µmol·h(-1)·100 g of body weight(-1) in the folate-replete rats, and this was decreased by 44% in folate-deficient rats. This decreased formate production was confirmed in isolated rat liver mitochondria where formate production from serine, the principal precursor of one-carbon groups, was decreased by 85%, although formate production from sarcosine and dimethylglycine (choline metabolites) was significantly increased. We attribute this unexpected result to the demonstrated production of formaldehyde by sarcosine dehydrogenase and dimethylglycine dehydrogenase from their respective substrates in the absence of tetrahydrofolate and subsequent formation of formate by formaldehyde dehydrogenase. Comparison of formate production with the ingestion of dietary formate precursors (serine, glycine, tryptophan, histidine, methionine, and choline) showed that ∼75% of these precursors were converted to formate, indicating that formate is a significant, although underappreciated end product of choline and amino acid oxidation. Ingestion of a high protein diet did not result in increased production of formate, suggesting a regulation of the conversion of these precursors at the mitochondrial level to formate.

Bmi1 promotes erythroid development through regulating ribosome biogenesis.

While Polycomb group protein Bmi1 is important for stem cell maintenance, its role in lineage commitment is largely unknown. We have identified Bmi1 as a novel regulator of erythroid development. Bmi1 is highly expressed in mouse erythroid progenitor cells and its deficiency impairs erythroid differentiation. BMI1 is also important for human erythroid development. Furthermore, we discovered that loss of Bmi1 in erythroid progenitor cells results in decreased transcription of multiple ribosomal protein genes and impaired ribosome biogenesis. Bmi1 deficiency stabilizes p53 protein, leading to upregulation of p21 expression and subsequent G0/G1 cell cycle arrest. Genetic inhibition of p53 activity rescues the erythroid defects seen in the Bmi1 null mice, demonstrating that a p53-dependent mechanism underlies the pathophysiology of the anemia. Mechanistically, Bmi1 is associated with multiple ribosomal protein genes and may positively regulate their expression in erythroid progenitor cells. Thus, Bmi1 promotes erythroid development, at least in part through regulating ribosome biogenesis. Ribosomopathies are human disorders of ribosome dysfunction, including Diamond-Blackfan anemia (DBA) and 5q- syndrome, in which genetic abnormalities cause impaired ribosome biogenesis, resulting in specific clinical phenotypes. We observed that BMI1 expression in human hematopoietic stem and progenitor cells from patients with DBA is correlated with the expression of some ribosomal protein genes, suggesting that BMI1 deficiency may play a pathological role in DBA and other ribosomopathies.