Parental leave, childcare policies, and workplace bias for hepatology professionals: A national survey.

BACKGROUND: The presence of workplace bias around child-rearing and inadequate parental leave may negatively impact childbearing decisions and sex equity in hepatology. This study aimed to understand the influence of parental leave and child-rearing on career advancement in hepatology. METHODS: A cross-sectional survey of physician members of the American Association for the Study of Liver Diseases (AASLD) was distributed through email listserv in January 2021. The 33-item survey included demographic questions, questions about bias, altering training, career plans, family planning, parental leave, and work accommodations. RESULTS: Among 199 US physician respondents, 65.3% were women, and 83.4% (n = 166) were attendings. Sex and racial differences were reported in several domains, including paid leave, perceptions of bias, and child-rearing. Most women (79.3%) took fewer than the recommended 12 paid weeks of parental leave for their first child (average paid leave 7.5 wk for women and 1.7 for men). A majority (75.2%) of women reported workplace discrimination, including 83.3% of Black and 62.5% of Hispanic women. Twenty percent of women were asked about their/their partners' pregnancy intentions or child-rearing plans during interviews for training. Women were more likely to alter career plans due to child-rearing (30.0% vs. 15.9%, p = 0.030). Women were also more likely to delay having children than men (69.5% vs.35.9%). CONCLUSIONS: Women reported sex and maternity bias in the workplace and during training interviews, which was more frequently experienced by Black and Hispanic women. As two-thirds of women had children during training, it is a particularly influential time to reevaluate programmatic support to address long-term gender disparities in career advancement.

A MATLAB-based app to improve LC-MS/MS data analysis for N-linked glycan peak identification.

BACKGROUND: Glycosylation is an important modification to proteins that plays a significant role in biological processes. Glycan structures are characterized by liquid chromatography (LC) combined with mass spectrometry (MS), but data interpretation of LC/MS and MS/MS data can be time-consuming and arduous when analyzed manually. Most of glycan analysis requires dedicated glycobioinformatics tools to process MS data, identify glycan structure, and display the results. However, software tools currently available are either too costly or heavily focused on academic applications, limiting their use within the biopharmaceutical industry for implementing the standardized LC/MS glycan analysis in high-throughput manner. Additionally, few tools provide the capability to generate report-ready annotated MS/MS glycan spectra. RESULTS: Here, we present a MATLAB-based app, GlyKAn AZ, which can automate data processing, glycan identification, and customizable result displays in a streamlined workflow. MS1 and MS2 mass search algorithms along with glycan databases were developed to confirm the fluorescent labeled N-linked glycan species based on accurate mass. A user-friendly graphical user interface (GUI) streamlines the data analysis process, making it easy to implement the software tool in biopharmaceutical analytical laboratories. The databases provided with the app can be expanded through the Fragment Generator functionality which automatically identifies fragmentation patterns for new glycans. The GlyKAn AZ app can automatically annotate the MS/MS spectra, yet this data display feature remains flexible and customizable by users, saving analysts' time in generating individual report-ready spectra figures. This app accepts both OrbiTrap and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS data and was successfully validated by identifying all glycan species that were previously identified manually. CONCLUSIONS: The GlyKAn AZ app was developed to expedite glycan analysis while maintaining a high level of accuracy in positive identifications. The app's customizable user inputs, polished figures and tables, and unique calculated outputs set it apart from similar software and greatly improve the current manual analysis workflow. Overall, this app serves as a tool for streamlining glycan identification for both academic and industrial needs.

A Comparison of Dopaminergic and Cholinergic Populations Reveals Unique Contributions of VTA Dopamine Neurons to Short-Term Memory.

We systematically compare the contributions of two dopaminergic and two cholinergic ascending populations to a spatial short-term memory task in rats. In ventral tegmental area dopamine (VTA-DA) and nucleus basalis cholinergic (NB-ChAT) populations, trial-by-trial fluctuations in activity during the delay period relate to performance with an inverted-U, despite the fact that both populations have low activity during that time. Transient manipulations reveal that only VTA-DA neurons, and not the other three populations we examine, contribute causally and selectively to short-term memory. This contribution is most significant during the delay period, when both increases and decreases in VTA-DA activity impair short-term memory. Our results reveal a surprising dissociation between when VTA-DA neurons are most active and when they have the biggest causal contribution to short-term memory, and they also provide support for classic ideas about an inverted-U relationship between neuromodulation and cognition.

Author Correction: Hexokinase-2 depletion inhibits glycolysis and induces oxidative phosphorylation in hepatocellular carcinoma and sensitizes to metformin.

In the originally published version of this Article, the colours of the bars in Fig. 4b were inadvertently switched during the production process, such that 'HK2-Dox' and 'HK2+Dox' were depicted in red and 'Nt-Dox' and 'Nt+Dox' were depicted in blue. These errors have now been corrected in both the PDF and HTML versions of the Article.

Hexokinase-2 depletion inhibits glycolysis and induces oxidative phosphorylation in hepatocellular carcinoma and sensitizes to metformin.

Hepatocellular carcinoma (HCC) cells are metabolically distinct from normal hepatocytes by expressing the high-affinity hexokinase (HK2) and suppressing glucokinase (GCK). This is exploited to selectively target HCC. Hepatic HK2 deletion inhibits tumor incidence in a mouse model of hepatocarcinogenesis. Silencing HK2 in human HCC cells inhibits tumorigenesis and increases cell death, which cannot be restored by GCK or mitochondrial binding deficient HK2. Upon HK2 silencing, glucose flux to pyruvate and lactate is inhibited, but TCA fluxes are maintained. Serine uptake and glycine secretion are elevated suggesting increased requirement for one-carbon contribution. Consistently, vulnerability to serine depletion increases. The decrease in glycolysis is coupled to elevated oxidative phosphorylation, which is diminished by metformin, further increasing cell death and inhibiting tumor growth. Neither HK2 silencing nor metformin alone inhibits mTORC1, but their combination inhibits mTORC1 in an AMPK-independent and REDD1-dependent mechanism. Finally, HK2 silencing synergizes with sorafenib to inhibit tumor growth.

Enzyme I facilitates reverse flux from pyruvate to phosphoenolpyruvate in Escherichia coli.

The bacterial phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) consists of cascading phosphotransferases that couple the simultaneous import and phosphorylation of a variety of sugars to the glycolytic conversion of phosphoenolpyruvate (PEP) to pyruvate. As the primary route of glucose uptake in E. coli, the PTS plays a key role in regulating central carbon metabolism and carbon catabolite repression, and is a frequent target of metabolic engineering interventions. Here we show that Enzyme I, the terminal phosphotransferase responsible for the conversion of PEP to pyruvate, is responsible for a significant in vivo flux in the reverse direction (pyruvate to PEP) during both gluconeogenic and glycolytic growth. We use 13C alanine tracers to quantify this back-flux in single and double knockouts of genes relating to PEP synthetase and PTS components. Our findings are relevant to metabolic engineering design and add to our understanding of gene-reaction connectivity in E. coli.

Targeted Antioxidant, Catalase-SKL, Reduces Beta-Amyloid Toxicity in the Rat Brain.

Accumulation of beta-amyloid (Aß) in the brain has been implicated as a major contributor to the cellular pathology and cognitive impairment observed in Alzheimer's disease. Beta-amyloid may exert its toxic effects by increasing reactive oxygen species and neuroinflammation in the brain. This study set out to investigate whether a genetically engineered derivative of the peroxisomal antioxidant enzyme catalase (CAT-SKL), is able to reduce the toxicity induced by intracerebroventricular injection of Aß25-35 in the mature rat brain. Histopathological and immunohistochemical analyses were used to evaluate neuroinflammation, and neuronal loss. Spatial learning and reference memory was assessed using the Morris water maze. CAT-SKL treatment was able to reduce the pathology induced by Aß25-35 toxicity by significantly decreasing microglia activation in the basal forebrain and thalamus, and reducing cholinergic loss in the basal forebrain. Aß25-35 animals showed deficits in long-term reference memory in the Morris water maze, while Aß25-35 animals treated with CAT-SKL did not demonstrate long-term memory impairments. This preclinical data provides support for the use of CAT-SKL in reducing neuroinflammation and long-term reference memory deficits induced by Aß25-35.

CO2 fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion.

Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO2 due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO2) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO2 emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H2) is provided, the fermentation emits no CO2. Finally, we show that mixotrophy is a general trait among acetogens.

Dissociated sequential activity and stimulus encoding in the dorsomedial striatum during spatial working memory.

Several lines of evidence suggest that the striatum has an important role in spatial working memory. The neural dynamics in the striatum have been described in tasks with short delay periods (1-4 s), but remain largely uncharacterized for tasks with longer delay periods. We collected and analyzed single unit recordings from the dorsomedial striatum of rats performing a spatial working memory task with delays up to 10 s. We found that neurons were activated sequentially, with the sequences spanning the entire delay period. Surprisingly, this sequential activity was dissociated from stimulus encoding activity, which was present in the same neurons, but preferentially appeared towards the onset of the delay period. These observations contrast with descriptions of sequential dynamics during similar tasks in other brains areas, and clarify the contribution of the striatum to spatial working memory.

13C metabolic flux analysis of microbial and mammalian systems is enhanced with GC-MS measurements of glycogen and RNA labeling.

13C metabolic flux analysis (13C-MFA) is a widely used tool for quantitative analysis of microbial and mammalian metabolism. Until now, 13C-MFA was based mainly on measurements of isotopic labeling of amino acids derived from hydrolyzed biomass proteins and isotopic labeling of extracted intracellular metabolites. Here, we demonstrate that isotopic labeling of glycogen and RNA, measured with gas chromatography-mass spectrometry (GC-MS), provides valuable additional information for 13C-MFA. Specifically, we demonstrate that isotopic labeling of glucose moiety of glycogen and ribose moiety of RNA greatly enhances resolution of metabolic fluxes in the upper part of metabolism; importantly, these measurements allow precise quantification of net and exchange fluxes in the pentose phosphate pathway. To demonstrate the practical importance of these measurements for 13C-MFA, we have used Escherichia coli as a model microbial system and CHO cells as a model mammalian system. Additionally, we have applied this approach to determine metabolic fluxes of glucose and xylose co-utilization in the E. coli ΔptsG mutant. The convenience of measuring glycogen and RNA, which are stable and abundant in microbial and mammalian cells, offers the following key advantages: reduced sample size, no quenching required, no extractions required, and GC-MS can be used instead of more costly LC-MS/MS techniques. Overall, the presented approach for 13C-MFA will have widespread applicability in metabolic engineering and biomedical research.

Motor and Hippocampal Dependent Spatial Learning and Reference Memory Assessment in a Transgenic Rat Model of Alzheimer's Disease with Stroke.

Alzheimer's disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk factor for AD, stroke has also been implicated as a risk factor and an exacerbating factor. The co-morbidity of stroke and AD results in worsened stroke-related motor control and AD-related cognitive deficits when compared to each condition alone. To model the combined condition of stroke and AD, a novel transgenic rat model of AD, with a mutated form of amyloid precursor protein (a key protein involved in the development of AD) incorporated into its DNA, is given a small unilateral striatal stroke. For a model with the combination of both stroke and AD, behavioral tests that assess stroke-related motor control, locomotion and AD-related cognitive function must be implemented. The cylinder task involves a cost-efficient, multipurpose apparatus that assesses spontaneous forelimb motor use. In this task, a rat is placed in a cylindrical apparatus, where the rat will spontaneously rear and contact the wall of the cylinder with its forelimbs. These contacts are considered forelimb motor use and quantified during video analysis after testing. Another cost-efficient motor task implemented is the beam-walk task, which assesses forelimb control, hindlimb control and locomotion. This task involves a rat walking across a wooden beam allowing for the assessment of limb motor control through analysis of forelimb slips, hindlimb slips and falls. Assessment of learning and memory is completed with Morris water maze for this behavioral paradigm. The protocol starts with spatial learning, whereby the rat locates a stationary hidden platform. After spatial learning, the platform is removed and both short-term and long-term spatial reference memory is assessed. All three of these tasks are sensitive to behavioral differences and completed within 28 days for this model, making this paradigm time-efficient and cost-efficient.

Extent of central neck dissection among thyroid cancer surgeons: Cross-sectional analysis.

BACKGROUND: It is unclear if surgeons are performing comprehensive central neck dissections for well-differentiated thyroid cancer. The purpose of this study was to determine mean lymph node retrieval in central neck dissection as well as variability across surgeons and institutions. METHODS: A prospectively collected database identified 18 surgeons performing 425 central neck dissections, 313 unilateral and 112 bilateral. Demographics, perioperative, and pathologic factors were analyzed. RESULTS: Mean lymph node yield was 7.4 and 11.9 for unilateral and bilateral central neck dissection, respectively. Although 224 central neck dissections were prophylactic, both total and pathologic lymph node yields were significantly higher in therapeutic central neck dissection. There was a significant variation in lymph node yield across individual surgeons, institutions, and regions. High-volume central neck dissection surgeons have significantly lower lymph node yield compared to low-volume surgeons. CONCLUSION: Central neck dissection seems to be performed adequately; however, there is a significant variation in lymph node yield. Future initiatives should try to standardize the central neck dissections performed, with emphasis on obtaining a sufficient yield. © 2015 Wiley Periodicals, Inc. Head Neck 38: E328-E332, 2016.

Probiotics are helpful in hepatic encephalopathy: a meta-analysis of randomized trials.

BACKGROUND: Hepatic encephalopathy (HE) is a major complication of cirrhosis and is associated with decreased survival and increased health care utilization. AIM: The aim of this study was to evaluate the efficacy of probiotics in the management minimal hepatic encephalopathy HE (MHE) and overt HE (OHE) in comparison to no treatment/placebo and lactulose. METHODS: The main outcomes measured were mortality, improvement in MHE, progression to OHE in patients with MHE and hospitalization. We calculated odds ratios (OR) with 95% confidence intervals (CI). Study heterogeneity was assessed using the I(2) statistic. RESULTS: Fourteen studies totalling 1152 patients were included in the analysis. The use of probiotics had no impact on the overall mortality when compared to either lactulose (OR: 1.07, 95% CI: 0.47-2.44, P = 0.88) or no treatment/placebo (OR: 0.69, 95% CI: 0.42-1.14, P = 0.15). When probiotics was compared to no treatment/placebo, it was associated with a significant improvement in MHE (OR: 3.91, 95% CI: 2.25-6.80, P < 0.00001), decreased hospitalization rates (OR: 0.53, 95% CI: 0.33-0.86, P = 0.01) and decreased progression to overt hepatic encephalopathy (OR: 0.40, 95% CI: 0.26-0.60, P < 0.0001). However when compared to lactulose, probiotics did not show a significant difference in improvement of MHE (OR: 0.81, 95% CI: 0.52-1.27, P = 0.35), hospitalization rates (OR: 1.02, 95% CI: 0.52-1.99, P = 0.96) or progression to overt hepatic encephalopathy (OR: 1.24, 95% CI 0.73-2.10, P = 0.42). CONCLUSIONS: Overall the use of probiotics was more effective in decreasing hospitalization rates, improving MHE and preventing progression to OHE in patients with underlying MHE than placebo, but similar to that seen with lactulose. The use of probiotics did not affect mortality rates.

Management of Hepatocellular Carcinoma: Current Status and Future Directions.

Hepatocellular carcinoma (HCC) is the second most common cause of cancer death worldwide. This cancer commonly arises against a background of chronic liver disease. As a result, a patient with HCC requires multidisciplinary care. Treatment options vary widely based on tumor burden and metastases. The most widely utilized staging system is the Barcelona Clinic Liver Cancer staging system, which recommends treatments based on tumor size and the underlying liver disease and functional status of the patient. Treatment options range from surgical resection or transplantation to locoregional therapies with modalities such as radiofrequency ablation and transarterial chemoembolization to systemic chemotherapies. Future care involves the development of combination therapies that afford the best tumor response, further clarification of the patients best suited for therapies and the development of new oral chemotherapeutic agents.

Comparison of tibial plateau angles in small and large breed dogs.

Cranial cruciate ligament (CCL) disease can affect dogs of all sizes. The literature describing tibial plateau angle (TPA) in small breed dogs is limited. A retrospective study was conducted in unselected dogs presented for stifle or tibial examination to compare TPA in small breed dogs (n = 146 dogs, 185 stifles) versus large breed dogs (n = 200 dogs, 265 stifles). Small breed dogs had a mean TPA 3.1° ± 0.6° higher than large breed dogs. There were higher TPAs in spayed females and castrated males for all dogs compared with intact males (3.6° ± 1.0° and 2.7° ± 1.0°, respectively). Dogs with unilateral and bilateral CCL disease had higher TPAs compared to dogs with intact CCLs (2.0° ± 0.7° and 2.5° ± 0.8°, respectively). Tibial morphology differs between large and small breed dogs; however, the significance of the impact of TPA on CCL disease in small breed dogs is unknown.

Comparaison des angles du plateau tibial chez les chiens de petite et de grande races. La maladie du ligament cruciforme crânien (LCC) peut affecter les chiens de toutes les tailles. La littérature décrivant l'angle du plateau tibial (APT) chez les chiens de petites races est limitée. Une étude rétrospective a été réalisée chez des chiens non sélectionnés présentés pour un examen du grasset ou du tibia pour comparer l'APT chez les chiens de petite race (n = 146 chiens, 185 grassets) par rapport aux chiens de grande race (n = 200 chiens, 265 grassets). Les chiens de petite race présentait un APT moyen de 3,1° ± 0,6° de plus que les chiens de grande race. Il y avait des APT supérieurs chez les femelles stérilisées et les mâles castrés pour tous les chiens comparativement aux mâles intacts (3,6° ± 1,0° et 2,7° ± 1,0°, respectivement). Les chiens atteints d'une maladie LCC unilatérale et bilatérale présentaient des APT supérieurs comparativement aux chiens avec des LCC intacts (2,0° ± 0,7° et 2,5° ± 0,8°, respectivement). La morphologie tibiale diffère entre les chiens de grande et de petite race. Cependant, l'importance de l'impact de l'APT sur la maladie LCC chez les chiens de petite race est inconnue.(Traduit par Isabelle Vallières).

Parallel labeling experiments validate Clostridium acetobutylicum metabolic network model for (13)C metabolic flux analysis.

In this work, we provide new insights into the metabolism of Clostridium acetobutylicum ATCC 824 obtained using a systematic approach for quantifying fluxes based on parallel labeling experiments and (13)C-metabolic flux analysis ((13)C-MFA). Here, cells were grown in parallel cultures with [1-(13)C]glucose and [U-(13)C]glucose as tracers and (13)C-MFA was used to quantify intracellular metabolic fluxes. Several metabolic network models were compared: an initial model based on current knowledge, and extended network models that included additional reactions that improved the fits of experimental data. While the initial network model did not produce a statistically acceptable fit of (13)C-labeling data, an extended network model with five additional reactions was able to fit all data with 292 redundant measurements. The model was subsequently trimmed to produce a minimal network model of C. acetobutylicum for (13)C-MFA, which could still reproduce all of the experimental data. The flux results provided valuable new insights into the metabolism of C. acetobutylicum. First, we found that TCA cycle was effectively incomplete, as there was no measurable flux between α-ketoglutarate and succinyl-CoA, succinate and fumarate, and malate and oxaloacetate. Second, an active pathway was identified from pyruvate to fumarate via aspartate. Third, we found that isoleucine was produced exclusively through the citramalate synthase pathway in C. acetobutylicum and that CAC3174 was likely responsible for citramalate synthase activity. These model predictions were confirmed in several follow-up tracer experiments. The validated metabolic network model established in this study can be used in future investigations for unbiased (13)C-flux measurements in C. acetobutylicum.

trans Fatty acids in the Canadian food supply: an updated analysis.

BACKGROUND: Dietary trans fatty acids (TFAs) increase the risk of heart disease. In 2007, Canada set voluntary TFA limits for industrial TFAs added to food and encouraged substitution of TFAs with unsaturated fats during reformulation. No longitudinal follow-up assessment of TFA amounts in foods has occurred in Canada since termination of a government-led Trans Fat Monitoring Program (TFMP). OBJECTIVE: The objective was to conduct an updated assessment and longitudinally evaluate TFA amounts in the food supply and to determine whether saturated fats have replaced TFAs in reformulation. DESIGN: This was a cross-sectional study that used 3 databases: TFMP (Health Canada, 2005-2009; n = 921), the University of Toronto Food Label Information Program (2010-2011; n = 5544), and the Restaurant Database (2010; n = 4272). Outcomes were TFAs as a percentage of fat, proportion of foods meeting TFA limits, and saturated fat amounts in foods with high or low TFAs. RESULTS: The proportion of foods meeting TFA limits improved from 75% in 2005-2009 to 97% in 2010-2011, particularly in the following packaged foods: croissants (25% to 100%), pies (36% to 98%), cakes (43% to 90%), and garlic spreads (33% to 100%). Most restaurant categories assessed by the TFMP had 100% of foods meeting TFA limits. Some categories had a large proportion that exceeded TFA limits: dairy-free cheeses (100%), frosting (72.0%), lard and shortening (66.7%), coffee whiteners (66.7%), and restaurant-prepared biscuits and scones (47.4%). Saturated fat amounts were significantly higher (P < 0.05) among some foods with the lowest TFAs, such as cookies, brownies and squares, cakes with pudding/mousse, dessert toppings, and lard and shortening. CONCLUSIONS: There has been an impressive improvement in TFA amounts in the Canadian food supply since the termination of the TFMP. However, action by the food industry is required to reduce TFAs in foods that exceed the recommended TFA limits and to minimize the use of saturated fats in replacing TFAs during reformulation.

A comprehensive analysis of sodium levels in the Canadian packaged food supply.

BACKGROUND: Population-wide sodium reduction strategies aim to reduce the cardiovascular burden of excess dietary sodium. Lowering sodium in packaged foods, which contribute the most dietary sodium, is an important intervention to lower population intakes. PURPOSE: To determine sodium levels in Canadian packaged foods and evaluate the proportion of foods meeting sodium benchmark targets set by Health Canada. METHODS: A cross-sectional analysis of 7,234 packaged foods available in Canada in 2010-2011. Sodium values were obtained from the Nutrition Facts table. RESULTS: Overall, 51.4% of foods met one of the sodium benchmark levels: 11.5% met Phase 1, 11.1% met Phase 2, and 28.7% met 2016 goal (Phase 3) benchmarks. Food groups with the greatest proportion meeting goal benchmarks were dairy (52.0%) and breakfast cereals (42.2%). Overall, 48.6% of foods did not meet any benchmark level and 25% of all products exceeded maximum levels. Meats (61.2%) and canned vegetables and legumes (29.6%) had the most products exceeding maximum levels. The range of sodium within and between food categories was highly variable. Food categories highest in sodium (mg/serving) were dry, condensed, and ready-to-serve soups (834±256, 754±163, and 636±173, respectively); oriental noodles (783±433); broth (642±239); and frozen appetizers/sides (642±292). CONCLUSIONS: These data provide a critical baseline assessment for monitoring sodium levels in Canadian foods. Although some segments of the market are making progress toward sodium reduction, all sectors need encouragement to continue to reduce the amount of sodium added during food processing.