Complications of pediatric macrocystic lymphatic malformations of the head and neck: a survival analysis of treated and untreated patients.

OBJECTIVE: To compare events of recurrent swelling between treated and untreated patients with macrocystic lymphatic malformations of the head and neck not involving the airway. The frequency and timing of emergency department (ED) visits related to the event were analysed to provide data on efficacy and ideal timing of treatment. METHODS: A 5-year retrospective review of a hospital database was conducted reviewing 35 patients (15 female, 20 male; mean age 3.9 years) with macrocystic lymphatic malformations of the head and neck not involving the airway. Patients treated with oral medications were excluded. A survival analysis was performed comparing the incidence of recurrent swelling of the malformation. A Cox regression analysis was conducted using age, gender, diameter of lymphatic malformation at presentation, and echogenicity on US as covariates. Fisher's test and mean comparisons were performed to correlate the populations baselines and the number and frequency of ED visits between the 2 groups. RESULTS: Thirteen patients underwent sclerotherapy soon after initial presentation and 22 elected for observation. The two baseline populations differed at presentation with the treatment group being younger (1.4 ± 2.4 vs. 5.4 ± 6.3 years, p = 0.03) and with larger lesions (5.7 ± 2.7 vs. 4.0 ± 1.7 cm p = 0.03). Mean follow-up time was 2.7 years. Survival analysis showed 1 or multiple recurrences affected 16 patients in the untreated group and 3 patients in the treated group. (p = 0.04). Age, gender, diameter of the lesion at presentation and increased echogenicity on US were not predictive factors of recurrence. Although the probability of visiting the ED at least once did not differ between the two groups (p = 0.42), patients from the non-treatment group were more likely to visit the ED more than once (p = 0.03). CONCLUSIONS: Sclerotherapy treatment may reduce the chance of recurrent swelling or an event after initial presentation to the ED.

Spathaspora passalidarum selected for resistance to AFEX hydrolysate shows decreased cell yield.

This study employed cell recycling, batch adaptation, cell mating and high-throughput screening to select adapted Spathaspora passalidarum strains with improved fermentative ability. The most promising candidate YK208-E11 (E11) showed a 3-fold increase in specific fermentation rate compared to the parental strain and an ethanol yield greater than 0.45 g/g substrate while co-utilizing cellobiose, glucose and xylose. Further characterization showed that strain E11 also makes 40% less biomass compared to the parental strain when cultivated in rich media under aerobic conditions. A tetrazolium agar overlay assay in the presence of respiration inhibitors, including rotenone, antimycin A, KCN and salicylhydroxamic acid elucidated the nature of the mutational events. Results indicated that E11 has a deficiency in its respiration system that could contribute to its low cell yield. Strain E11 was subjected to whole genome sequencing and an ∼11 kb deletion was identified; the open reading frames absent in strain E11 code for proteins with predicted functions in respiration, cell division and the actin cytoskeleton, and may contribute to the observed physiology of the adapted strain. Results of the tetrazolium overlay also suggest that cultivation on xylose affects the respiration capacity in the wild-type strain, which could account for its faster fermentation of xylose as compared to glucose. These results support our previous finding that S. passalidarum has highly unusual physiological responses to xylose under oxygen limitation.

Media Impacts on Women's Fertility Desires: A Prolonged Exposure Experiment.

Media exposure may have implications for family planning, a public health issue of key importance. Drawing on social comparison theory and social identity theory, a prolonged exposure experiment examined whether media portrayals of women's social roles affect fertility desires among 166 American, nonstudent, never married, childless women ages 21-35 years old. After sign-up and baseline sessions, participants viewed magazine pages five days in a row. Stimuli presented women in either mother/homemaker roles, beauty ideal roles, or professional roles. Three days later, participants again indicated their number of desired children and time planned until first birth. Exposure to mother/homemaker and beauty ideal portrayals increased the number of desired children across time. Exposure to professional portrayals increased the time planned until 1st birth compared to beauty ideal portrayals-this impact was partially mediated by a shift toward more progressive gender norms (per social identity theory) and assimilation (per social comparison theory).

Nitrogen limitation, oxygen limitation, and lipid accumulation in Lipomyces starkeyi.

Lipid production by oleaginous yeasts is optimal at high carbon-to-nitrogen ratios. In the current study, nitrogen and carbon consumption by Lipomyces starkeyi were directly measured in defined minimal media with nitrogen content and agitation rates as variables. Shake flask cultures with an initial C:N ratio of 72:1 cultivated at 200rpm resulted in a lipid output of 10g/L, content of 55%, yield of 0.170g/g, and productivity of 0.06g/L/h. All of these values decreased by ≈50-60% when the agitation rate was raised to 300rpm or when the C:N ratio was lowered to 24:1, demonstrating the importance of these parameters. Under all conditions, L. starkeyi cultures tolerated acidified media (pH≈2.6) without difficulty, and produced considerable amounts of alcohols; including ethanol, mannitol, arabitol, and 2,3-butanediol. L. starkeyi also produced lipids from a corn stover hydrolysate, showing its potential to produce biofuels from renewable agricultural feedstocks.

Effects of aeration on growth, ethanol and polyol accumulation by Spathaspora passalidarum NRRL Y-27907 and Scheffersomyces stipitis NRRL Y-7124.

Spathaspora passalidarum NN245 (NRRL-Y27907) is an ascomycetous yeast that displays a higher specific fermentation rate with xylose than with glucose. Previous studies have shown that its capacity for xylose fermentation increases while cell yield decreases with decreasing aeration. Aeration optimization plays a crucial role in maximizing bioethanol production from lignocellulosic hydrolysates. Here, we compared the kinetics of S. passalidarum NN245 and Scheffersomyces (Pichia) stipitis NRRL Y-7124 fermenting 15% glucose, 15% xylose, or 12% xylose plus 3% glucose under four different aeration conditions. The maximum specific fermentation rate for S. passalidarum was 0.153 g ethanol/g CDW · h with a yield of 0.448 g/g from 150 g/L xylose at an oxygen transfer rate of 2.47 mmol O2 /L h. Increasing the OTR to 4.27 mmol O2 /L h. decreased the ethanol yield from 0.46 to 0.42 g/g xylose while increasing volumetric ethanol productivity from 0.52 to 0.8 g/L h. Both yeasts had lower cells yields and higher ethanol yields when growing on xylose than when growing on glucose. Acetic acid accretions of both strains correlated positively with increasing aeration. S. passalidarum secreted lower amounts of polyols compared to S. stipitis under most circumstances. In addition, the composition of polyols differed: S. passalidarum accumulated mostly xylitol and R,R-2,3-butanediol (BD) whereas S. stipitis accumulated mostly xylitol and ribitol when cultivated in xylose or a mixture of 12% xylose and 3% glucose. R,R-2,3-BD accumulation by S. passalidarum during xylose fermentation can be as much as four times of that by S. stipitis, and R,R-2,3-BD is also the most abundant byproduct after xylitol. The ratios of polyols accumulated by the two species under different aeration conditions and the implications of these observations for strain and process engineering are discussed.

Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover.

The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH.

An optimized transformation protocol for Lipomyces starkeyi.

We report the development of an efficient genetic transformation system for Lipomyces starkeyi based on a modified lithium acetate transformation protocol. L. starkeyi is a highly lipogenic yeast that grows on a wide range of substrates. The initial transformation rate for this species was extremely low, and required very high concentrations of DNA. A systematic approach for optimizing the protocol resulted in an increase in the transformation efficiency by four orders of magnitude. Important parameters included cell density, the duration of incubation and recovery periods, the heat shock temperature, and the concentration of lithium acetate and carrier DNA within the transformation mixture. We have achieved efficiencies in excess of 8,000 transformants/µg DNA, which now make it possible to screen libraries in the metabolic engineering of this yeast. Metabolic engineering based on this transformation system could improve lipogenesis and enable formation of higher value products.

Weighing women down: messages on weight loss and body shaping in editorial content in popular women's health and fitness magazines.

Exposure to idealized body images has been shown to lower women's body satisfaction. Yet some studies found the opposite, possibly because real-life media (as opposed to image-only stimuli) often embed such imagery in messages that suggest thinness is attainable. Drawing on social cognitive theory, the current content analysis investigated editorial body-shaping and weight-loss messages in popular women's health and fitness magazines. About five thousand magazine pages published in top-selling U.S. women's health and fitness magazines in 2010 were examined. The findings suggest that body shaping and weight loss are a major topic in these magazines, contributing to roughly one-fifth of all editorial content. Assessing standards of motivation and conduct, as well as behaviors promoted by the messages, the findings reflect overemphasis on appearance over health and on exercise-related behaviors over caloric reduction behaviors and the combination of both behaviors. These accentuations are at odds with public health recommendations.

Phenotypic selection of a wild Saccharomyces cerevisiae strain for simultaneous saccharification and co-fermentation of AFEX™ pretreated corn stover.

BACKGROUND: Simultaneous saccharification and co-fermentation (SSCF) process involves enzymatic hydrolysis of pretreated lignocellulosic biomass and fermentation of glucose and xylose in one bioreactor. The optimal temperatures for enzymatic hydrolysis are higher than the standard fermentation temperature of ethanologenic Saccharomyces cerevisiae. Moreover, degradation products resulting from biomass pretreatment impair fermentation of sugars, especially xylose, and can synergize with high temperature stress. One approach to resolve both concerns is to utilize a strain background with innate tolerance to both elevated temperatures and degradation products. RESULTS: In this study, we screened a panel of 108 wild and domesticated Saccharomyces cerevisiae strains isolated from a wide range of environmental niches. One wild strain was selected based on its growth tolerance to simultaneous elevated temperature and AFEX™ (Ammonia Fiber Expansion) degradation products. After engineering the strain with two copies of the Scheffersomyces stipitis xylose reductase, xylitol dehydrogenase and xylulokinase genes, we compared the ability of this engineered strain to the benchmark 424A(LNH-ST) strain in ethanol production and xylose fermentation in standard lab medium and AFEX pretreated corn stover (ACS) hydrolysates, as well as in SSCF of ACS at different temperatures. In SSCF of 9% (w/w) glucan loading ACS at 35°C, the engineered strain showed higher cell viabilities and produced a similar amount of ethanol (51.3 g/L) compared to the benchmark 424A(LNH-ST) strain. CONCLUSION: These results validate our approach in the selection of wild Saccharomyces cerevisiae strains with thermo-tolerance and degradation products tolerance properties for lignocellulosic biofuel production. The wild and domesticated yeast strains phenotyped in this work are publically available for others to use as genetic backgrounds for fermentation of their pretreated biomass at elevated temperatures.

Lipid profiles are associated with lesion formation over 24 months in interferon-ß treated patients following the first demyelinating event.

OBJECTIVES: To investigate the associations of serum lipid profile with disease progression in high-risk clinically isolated syndromes (CIS) after the first demyelinating event. METHODS: High density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) were obtained in pretreatment serum from 135 high risk patients with CIS (≥ 2 brain MRI lesions and ≥ 2 oligoclonal bands) enrolled in the Observational Study of Early Interferon ß-1a Treatment in High Risk Subjects after CIS study (SET study), which prospectively evaluated the effect of intramuscular interferon ß-1a treatment following the first demyelinating event. Thyroid stimulating hormone, free thyroxine, 25-hydroxy vitamin D3, active smoking status and body mass index were also obtained. Clinical and MRI assessments were obtained within 4 months of the initial demyelinating event and at 6, 12 and 24 months. RESULTS: The time to first relapse and number of relapses were not associated with any of the lipid profile variables. Higher LDL-C (p=0.006) and TC (p=0.001) levels were associated with increased cumulative number of new T2 lesions over 2 years. Higher free thyroxine levels were associated with lower cumulative number of contrast-enhancing lesions (p=0.008). Higher TC was associated as a trend with lower baseline whole brain volume (p=0.020). Higher high density lipoprotein was associated with higher deseasonalised 1,25-dihydroxy vitamin D3 (p=0.003) levels and a trend was found for deseasonalised 25-hydroxy vitamin D3 (p=0.014). CONCLUSIONS: In early multiple sclerosis, lipid profile variables particularly LDL-C and TC levels are associated with inflammatory MRI activity measures.

Environmental factors associated with disease progression after the first demyelinating event: results from the multi-center SET study.

OBJECTIVES: To investigate the associations of environmental MS risk factors with clinical and MRI measures of progression in high-risk clinically isolated syndromes (CIS) after the first demyelinating event. METHODS: We analyzed 211 CIS patients (age: 28.9±7.8 years) enrolled in the SET study, a multi-center study of high-risk CIS patients. Pre-treatment samples were analyzed for IgG antibodies against cytomegalovirus (anti-CMV), Epstein Barr virus (EBV) early nuclear antigen-1 (EBNA-1), viral capsid antigen (VCA), early antigen-diffuse (EA-D), 25 hydroxy-vitamin D3 and cotinine levels and HLA DRB1*1501 status. The inclusion criteria required evaluation within 4 months of the initial demyelinating event, 2 or more brain MRI lesions and the presence of two or more oligoclonal bands in cerebrospinal fluid. All patients were treated with interferon-beta. Clinical and MRI assessments were obtained at baseline, 6, 12, and 24 months. RESULTS: The time to first relapse decreased and the number of relapses increased with anti-CMV IgG positivity. Smoking was associated with increased number and volume of contrast-enhancing lesions (CEL) during the 2-year period. The cumulative number of CEL and T2 lesions during the 2-year period was greater for individuals in the highest quartile of anti-EBV VCA IgG antibodies. The percent loss of brain volume was increased for those in the highest quartile of with anti-EBV VCA IgG antibodies. CONCLUSIONS: Relapses in CIS patients were associated with CMV positivity whereas anti-EBV VCA positivity was associated with progression on MRI measures, including accumulation of CEL and T2 lesions and development of brain atrophy.

Cofermentation of glucose, xylose, and cellobiose by the beetle-associated yeast Spathaspora passalidarum.

Fermentation of cellulosic and hemicellulosic sugars from biomass could resolve food-versus-fuel conflicts inherent in the bioconversion of grains. However, the inability to coferment glucose and xylose is a major challenge to the economical use of lignocellulose as a feedstock. Simultaneous cofermentation of glucose, xylose, and cellobiose is problematic for most microbes because glucose represses utilization of the other saccharides. Surprisingly, the ascomycetous, beetle-associated yeast Spathaspora passalidarum, which ferments xylose and cellobiose natively, can also coferment these two sugars in the presence of 30 g/liter glucose. S. passalidarum simultaneously assimilates glucose and xylose aerobically, it simultaneously coferments glucose, cellobiose, and xylose with an ethanol yield of 0.42 g/g, and it has a specific ethanol production rate on xylose more than 3 times that of the corresponding rate on glucose. Moreover, an adapted strain of S. passalidarum produced 39 g/liter ethanol with a yield of 0.37 g/g sugars from a hardwood hydrolysate. Metabolome analysis of S. passalidarum before onset and during the fermentations of glucose and xylose showed that the flux of glycolytic intermediates is significantly higher on xylose than on glucose. The high affinity of its xylose reductase activities for NADH and xylose combined with allosteric activation of glycolysis probably accounts in part for its unusual capacities. These features make S. passalidarum very attractive for studying regulatory mechanisms enabling bioconversion of lignocellulosic materials by yeasts.

The implications of long-term acute care hospital transfer practices for measures of in-hospital mortality and length of stay.

RATIONALE: The National Quality Forum recently endorsed in-hospital mortality and intensive care unit length of stay (LOS) as quality indicators for patients in the intensive care unit. These measures may be affected by transferring patients to long-term acute care hospitals (LTACs). OBJECTIVES: To quantify the implications of LTAC transfer practices on variation in mortality index and LOS index for patients in academic medical centers. METHODS: We used a cross-sectional study design using data reported to the University HealthSystem Consortium from 2008-2009. Data were from patients who were mechanically ventilated for more than 96 hours. MEASUREMENTS AND MAIN RESULTS: Using linear regression, we measured the association between mortality index and LTAC transfer rate, with the hospital as the unit of analysis. Similar analyses were conducted for LOS index and cost index. A total of 137 hospitals were analyzed, averaging 534 transfers to LTAC per hospital during the study period. Mean±SD in-hospital mortality was 24±6.4%, and observed LOS was 30.4±8.2 days. The mean LTAC transfer rate was 15.7±13.7%. Linear regression demonstrated a significant correlation between transfer rate and mortality index (R2=0.14; P<0.0001) and LOS index (R2=0.43; P<0.0001). CONCLUSIONS: LTAC hospital transfer rate has a significant impact on reported mortality and LOS indices for patients requiring prolonged acute mechanical ventilation. This is an example of factors unrelated to quality of medical care or illness severity that must be considered when interpreting mortality and LOS as quality indicators.

HLA DRB1*1501 is only modestly associated with lesion burden at the first demyelinating event.

OBJECTIVES: The presence of MRI lesions at the first demyelinating event increases the risk of developing clinically definite multiple sclerosis (MS). The HLA DRB1*1501 genotype is linked to MS susceptibility but its relationship to quantitative MRI parameters at the first demyelinating event has not been assessed. The objectives were to assess the associations between HLA DRB1*1501 status and magnetic resonance imaging (MRI) measures in clinically isolated syndromes (CIS) at the first demyelinating event. METHODS: We genotyped 205 CIS patients (age: 29.0±7.7 years) enrolled in the Observational Study of Early Interferon beta 1-a Treatment in High Risk Subjects after CIS (SET study), a multi-center, clinical study of CIS for rs3135005, a single nucleotide polymorphism associated with HLA DRB1*1501 status. The inclusion criteria required 2 or more brain MRI lesions and the presence of two or more oligoclonal bands in cerebrospinal fluid. Clinical and MRI assessments were obtained within 4 months of the initial demyelinating event. RESULTS: The frequency of HLA DRB1*1501 positivity was 102/205 (49.7%). HLA DRB1*1501 positivity was associated with higher contrast-enhancing (CE) lesion number (p=0.002), higher CE-lesion volume (LV) (p<0.001) and exhibited a trend with higher T2-LV (p=0.012). There was no evidence for significant associations of HLA DRB1*1501 positivity with disability, symptoms at CIS presentation, whole brain, white and gray matter atrophy. CONCLUSIONS: HLA DRB1*1501 positivity is associated with increased brain inflammatory processes at first clinical onset. However, the effect sizes of the HLA DRB1*1501 associations with MRI are modest, which potentially limits the clinical usefulness.

Production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from plant oil by engineered Ralstonia eutropha strains.

The polyhydroxyalkanoate (PHA) copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB-co-HHx)] has been shown to have potential to serve as a commercial bioplastic. Synthesis of P(HB-co-HHx) from plant oil has been demonstrated with recombinant Ralstonia eutropha strains expressing heterologous PHA synthases capable of incorporating HB and HHx into the polymer. With these strains, however, short-chain-length fatty acids had to be included in the medium to generate PHA with high HHx content. Our group has engineered two R. eutropha strains that accumulate high levels of P(HB-co-HHx) with significant HHx content directly from palm oil, one of the world's most abundant plant oils. The strains express a newly characterized PHA synthase gene from the bacterium Rhodococcus aetherivorans I24. Expression of an enoyl coenzyme A (enoyl-CoA) hydratase gene (phaJ) from Pseudomonas aeruginosa was shown to increase PHA accumulation. Furthermore, varying the activity of acetoacetyl-CoA reductase (encoded by phaB) altered the level of HHx in the polymer. The strains with the highest PHA titers utilized plasmids for recombinant gene expression, so an R. eutropha plasmid stability system was developed. In this system, the essential pyrroline-5-carboxylate reductase gene proC was deleted from strain genomes and expressed from a plasmid, making the plasmid necessary for growth in minimal media. This study resulted in two engineered strains for production of P(HB-co-HHx) from palm oil. In palm oil fermentations, one strain accumulated 71% of its cell dry weight as PHA with 17 mol% HHx, while the other strain accumulated 66% of its cell dry weight as PHA with 30 mol% HHx.

Improved detergent-based recovery of polyhydroxyalkanoates (PHAs).

Extracting polyhydroxyalkanoate (PHA) polymer from bacterial cells often involves harsh conditions, including use of environmentally harmful solvents. We evaluated different detergents under various conditions to extract PHA from Ralstonia eutropha and Escherichia coli cells. Most detergents tested recovered highly pure PHA polymer from cells in amounts that depended on the percentage of polymer present in the cell. Detergents such as linear alkylbenzene sulfonic acid (LAS-99) produced a high yield of high purity polymer, and less detergent was needed compared to the amount of SDS to produce comparable yields. LAS-99 also has the advantage of being biodegradable and environmentally safe. Chemical extraction of PHA with detergents could potentially minimize or eliminate the need to use harsh organic solvents, thus making industrial PHA production a cleaner technology process.

Vitamin D metabolites are associated with clinical and MRI outcomes in multiple sclerosis patients.

PURPOSE: The associations between vitamin D and MRI measures of brain tissue injury have not been previously investigated in multiple sclerosis (MS). This research evaluates the significance of vitamin D and its active metabolites in brain tissue injury and clinical disability in MS patients. METHODS: The study population consisted of 193 MS patients (152 women and 41 men; mean age 46.1 (SD 8.4) years; disease duration 13.8 (SD 8.4) years). Serum levels of 25-hydroxyvitamin D(3) (25(OH)VD(3)), 25-hydroxyvitamin D(2) (25(OH)VD(2)), 1α, 25-dihydroxyvitamin D(3) (1, 25(OH)(2)VD(3)) and 24(R), 25-dihydroxyvitamin D(3) (24, 25(OH)(2)VD(3)) were measured using a novel capillary liquid-chromatography-mass spectrometry method. Disability was assessed with the Expanded Disability Status Scale (EDSS) and the MS Severity Scale (MSSS). MRI measures included T2 lesion volume (LV), T1-LV and brain parenchymal fraction. The associations between deseasonalised levels of vitamin D metabolites and clinical and MRI measurements were assessed using regression analyses. RESULTS: Lower deseasonalised levels of total 25(OH)VD (p=0.029), 25(OH)VD(3) (p=0.032) and 24, 25(OH)(2)VD(3) (p=0.005) were associated with higher MSSS. Similarly, lower deseasonalised levels of 24, 25(OH)(2)VD(3) (p=0.012) were associated with higher EDSS. Higher values of the 25(OH)VD(3) to 24, 25(OH)(2)VD(3) ratio were associated with higher MSSS (p=0.041) and lower brain parenchymal fraction (p=0.008). CONCLUSIONS: Vitamin D metabolites have protective associations with disability and brain atrophy in MS. In particular, the results indicate strong associations for the 24, 25(OH)(2)VD(3) metabolite, which has not been extensively investigated in MS patients.

Optimization of growth media components for polyhydroxyalkanoate (PHA) production from organic acids by Ralstonia eutropha.

We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of acetate dramatically affected the final pH of the growth medium. A model was constructed using our data that predicts the effects of these acids, individually and in combination, on cell dry weight (CDW), PHA content (%CDW), PHA production, 3HV in the polymer, and final culture pH. Cell growth and PHA production improved approximately 1.5-fold over initial conditions when the proportion of butyrate was increased. Optimization of the phosphate buffer content in medium containing higher amounts of butyrate improved cell growth and PHA production more than 4-fold. The validated organic acid mixture analysis model can be used to optimize R. eutropha culture conditions, in order to meet targets for PHA production and/or polymer HV content. By modifying the growth medium made from treated industrial waste, such as palm oil mill effluent, more PHA can be produced.

Digital and screen-film mammography: comparison of image acquisition and interpretation times.

OBJECTIVE: The objective of our study was to compare acquisition times and interpretation times of screening examinations using screen-film mammography and soft-copy digital mammography. MATERIALS AND METHODS: Technologist study acquisition time from examination initiation to release of the screenee was measured for both screen-film and digital mammography (100 cases each) in routine clinical practice. The total interpretation time for screening mammography was also measured for 183 hard-copy screen-film cases and 181 soft-copy digital cases interpreted by a total of seven breast imaging radiologists, four experienced breast imagers, and three breast imaging fellows. RESULTS: Screening mammography acquisition time averaged 21.6 minutes for screen-film and 14.1 minutes for digital, a highly significant 35% shorter time for digital than screen-film (p < 10(-17)). The average number of images per case acquired with digital mammography was higher than that for screen-film mammography (4.23 for screen-film, 4.50 for digital; p = 0.047). The total interpretation time averaged 1.4 minutes for screen-film mammography and 2.3 minutes for digital mammography, a highly significant 57% longer interpretation time for digital (p < 10(-11)). In addition, technical problems delaying interpretation were encountered in none of the 183 screen-film cases but occurred in nine (5%) of the 181 digital cases. CONCLUSION: Compared with screen-film mammography, the use of digital mammography for screening examinations significantly shortened acquisition time but significantly increased interpretation time. In addition, more technical problems were encountered that delayed the interpretation of digital cases.

Bioreactor culture of oil palm (Elaeis guineensis) and effects of nitrogen source, inoculum size, and conditioned medium on biomass production.

We report the successful culture of oil palm (Elaeis guineensis Jacq.) suspension cells in a bioreactor. In vitro propagation of this perennial monocotyledonous tree is an important part of the oil palm industry's approach to clonal propagation of high-yielding accessions. During culture of oil palm cells in a batch bioreactor, nutrients and extracellular metabolites were monitored, and kinetic parameters and nutrient-to-biomass conversion yields were calculated. The biomass increased approximately 3.5-fold per month, consistent with values reported for shake flask cultures. Although the carbon source was completely depleted by the end of the run, nitrogen sources remained in large excess and the sugar-to-biomass conversion yield remained low. Linear growth indicated that the cells were limited. The results obtained from the bioreactor runs indicated that we should be able to improve biomass production by carrying out optimization studies. Therefore, we initiated multi-factorial analyses using response surface experimental designs to investigate the effects of different nitrogen sources, as well as inoculum size and conditioned medium, on biomass production in flask cultures. Whereas glutamine does not have a significant effect on biomass production, ammonia has a positive effect up to an optimum concentration. Both inoculum density and conditioned medium have positive, synergistic effects on biomass production.