Consecutive Screening Rounds Research Articles

Combinatorial iterative method for metabolic engineering of Yarrowia lipolytica: Application for betanin biosynthesis

Combinatorial library-based metabolic engineering approaches allow lower cost and faster strain development. We developed a genetic toolbox EXPRESSYALI for combinatorial engineering of the oleaginous yeast Yarrowia lipolytica. The toolbox enables consecutive rounds of engineering, where up to three combinatorially assembled gene expression cassettes can be integrated into each yeast clone per round. The cassettes are integrated into distinct intergenic sites or an open reading frame of a target gene if a simultaneous gene knockout is desired. We demonstrate the application of the toolbox by optimizing the Y. lipolytica to produce the red beet color betanin via six consecutive rounds of genome editing and screening. The library size varied between 24 and 360. Library screening was facilitated by automated color-based colony picking. In the first round, betanin pathway genes were integrated, resulting in betanin titer of around 20 mg/L. Through the following five consecutive rounds, additional biosynthetic genes were integrated, and the precursor supply was optimized, resulting in a titer of 70 mg/L. Three beta-glucosidases were deleted to prevent betanin deglycosylation, which led to a betanin titer of 130 mg/L in a small scale and a titer of 1.4 g/L in fed-batch bioreactors. The EXPRESSYALI toolbox can facilitate metabolic engineering efforts in Y. lipolytica (available via AddGene Cat. Nr. 212682–212704, Addgene kit ID # 1000000245).

Screen and Optimization of an Aptamer for Alexandrium tamarense-A Common Toxin-Producing Harmful Alga.

Among all the paralytic shellfish toxins (PSTs)-producing algae, Alexandrium tamarense is one of the most widespread harmful species posing a serious threat to marine resources and human health. Therefore, it is extremely important to establish a rapid and accurate monitoring method for A. tamarense that can provide early warnings of harmful algal blooms (HABs) caused by this alga and limit the contamination due to PSTs. In this study, an ssDNA library was first obtained by whole cell systematic evolution of ligands by exponential enrichment after 18 consecutive rounds of iterative screening. After sequencing in combination with subsequent multiple alignment of sequences and secondary structure simulation, the library could be classified into 2 families, namely, Family1 and Family2, according to sequence similarity. Flow cytometry was used to test the affinity and cross-reactivity of Ata19, Ata6, Ata25 and Ata29 belonging to Family2. Ata19 was selected to be modified by truncation, through which a new resultant aptamer named as Ata19-1-1 was obtained. Ata19-1-1 with a KD of 75.16 ± 11.10nM displayed a much higher affinity than Ata19. The specificity test showed that Ata19-1-1 has the same discrimination ability as Ata19 and can at least distinguish the target microalga from other microalgae. The observation under a fluorescence microscopy showed that the A. tamarense cells labeled with Ata19-1-1 are exhibiting bright green fluorescence and could be easily identified, factually confirming the binding of the aptamer with target cells. In summary, the aptamer Ata19-1-1 produced in this study may serve as an ideal molecular recognition element for A. tamarense, which has the potential to be developed into a novel detection method for this harmful alga in the future.

Early screening outcomes before, during, and after a randomized controlled trial with digital breast tomosynthesis

PurposeTo describe and compare early screening outcomes before, during and after a randomized controlled trial with digital breast tomosynthesis (DBT) including synthetic 2D mammography versus standard digital mammography (DM) (To-Be 1) and a follow-up cohort study using DBT (To-Be 2). MethodsRetrospective results of 125,020 screening examinations from four consecutive screening rounds performed in 2014–2021 were described and compared for pre-To-Be 1 (DM), To-Be 1 (DM or DBT), To-Be 2 (DBT), and post-To-Be 2 (DM) cohorts. Descriptive analyses of rates of recall, biopsy, screen-detected and interval cancer, distribution of histopathologic tumor characteristics and time spent on image interpretation and consensus were presented for the four rounds including five cohorts, one cohort in each screening round except for the To-Be 1 trail, which included a DBT and a DM cohort. Odds ratios (OR) with 95% CIs was calculated for recall and cancer detection rates. ResultsRate of screen-detected cancer was 0.90% for women screened with DBT in To-Be 2 and 0.64% for DM in pre-To-Be 1. The rates did not differ for the To-Be 1 DM (0.61%), To-Be 1 DBT (0.66%) and post-To-Be 2 DM (0.67%) cohorts. The interval cancer rates ranged between 0.13% and 0.20%. The distribution of histopathologic tumor characteristics did not differ between the cohorts. ConclusionsScreening all women with DBT following a randomized controlled trial in an organized, population-based screening program showed a temporary increase in the rate of screen-detected cancer.

Colorectal cancer screening with faecal immunochemical test: Patterns of participation.

To evaluate participation and participation patterns in a population-based screening programme for colorectal cancer (CRC) using the faecal immunochemical test (FIT). All individuals invited to three consecutive screening rounds in the population-based CRC screening between October 2015 and December 2020 in the Stockholm-Gotland Region, Sweden were included. Patterns of participation were assessed. The study included 26 541 individuals which resulted in 79 623 screening events. The overall uptake rate was 71.5% and women had a significantly higher participation rate. The participation rate increased significantly between the first and third screening round for both men and women, and the increase was larger among men than women (66.1 to 70.7% vs. 73.1 to 75.4%). In total, 80.9% participated at least once. Consistent participation was the most common participation pattern (61.0%). The probability of attending all three consecutive rounds after initial participation was 87.7%. Over the three rounds, 17.4% participated after a reminder letter. Screening individuals attending after a reminder letter had a higher proportion of drop-outs in the following screening round compared to initial participants (15.4% vs 6.2%). A constant and high participation rate was observed in population-based FIT-screening for CRC. Initial participation was a strong predictor for continuous participation. The need for a reminder letter before participation was a risk factor for subsequent drop-out.

Comparison of Colonoscopy, Fecal Immunochemical Test, and Risk-Adapted Approach in a Colorectal Cancer Screening Trial (TARGET-C)

The screening yield and related cost of a risk-adapted screening approach compared with established screening strategies in population-based colorectal cancer (CRC) screening are not clear. We randomly allocated 19,373 participants into 1 of the 3 screening arms in a 1:2:2 ratio: (1) one-time colonoscopy (n= 3883); (2) annual fecal immunochemical test (FIT) (n= 7793); (3) annual risk-adapted screening (n= 7697), in which, based on the risk-stratification score, high-risk participants were referred for colonoscopy and low-risk ones were referred for FIT. Three consecutive screening rounds were conducted for both the FIT and the risk-adapted screening arms. Follow-up to trace the health outcome for all the participants was conducted over the 3-year study period. The detection rate of advanced colorectal neoplasia (CRC and advanced precancerous lesions) was the main outcome. The trial was registered in the Chinese Clinical Trial Registry (number: ChiCTR1800015506). In the colonoscopy, FIT, and risk-adapted screening arms over 3 screening rounds, the participation rates were 42.4%, 99.3%, and 89.2%, respectively; the detection rates for advanced neoplasm (intention-to-treat analysis) were 2.76%, 2.17%, and 2.35%, respectively, with an oddsratio (OR)colonoscopy vs FIT of 1.27 (95% confidence interval [CI]: 0.99-1.63; P= .056), an ORcolonoscopy vsrisk-adapted screening of 1.17 (95% CI, 0.91-1.49; P= .218), and an ORrisk-adapted screeningvs FIT of 1.09 (95% CI, 0.88-1.35; P= .438); the numbers of colonoscopies needed to detect 1 advanced neoplasm were 15.4, 7.8, and 10.2, respectively; the costs for detecting 1 advanced neoplasm from a government perspective using package payment format were 6928 Chinese Yuan (CNY) ($1004), 5821 CNY ($844), and 6694 CNY ($970), respectively. The risk-adapted approach is a feasible and cost-favorable strategy for population-based CRC screening and therefore could complement the well-established one-time colonoscopy and annual repeated FIT screening strategies. (Chinese Clinical Trial Registry; ChiCTR1800015506).

Acceleration of cervical cancer diagnosis with human papillomavirus testing below age 30: Observational study.

Several international cervical screening guidelines advise against using high-risk human papillomavirus (HR-HPV) testing in women younger than 30. The rationale for this in young women, lies in the potential for additional detection of both low-grade and high-grade cervical intraepithelial neoplasia (CIN) leading to unnecessary treatments without reducing the burden of cervical cancer. We studied 56 544 women screened at 24 to 29 with HR-HPV testing and 116 858 screened with liquid-based cytology (LBC) in the English HPV screening pilot. They were compared to 528 460 women screened at the age of 30 to 49. We studied the detection of cervical cancer and CIN2/3 across two consecutive screening rounds 3 years apart. At 24 to 29, a positive HR-HPV test detected more cases of cervical cancer in the prevalence round than did a positive LBC test (1.36/1000 screened vs 0.82/1000, ORadj : 1.61, 95% CI: 1.18-2.19). In women with a negative HR-HPV test, cervical cancer was diagnosed before or at the incidence round in 0.07/1000. After a negative LBC test, cancer detection reached 0.47/1000 and 40% of these cases were diagnosed at FIGO stage IB+. HR-HPV testing increased the detection of CIN2/3 diagnoses in two consecutive rounds combined by 30% (71.9/1000 vs 55.2/1000). The patterns of detection of cervical cancer and CIN2/3 were almost identical at older ages. These data support using HR-HPV testing for screening of women younger than 30, which not only accelerates the diagnosis of cervical cancer but leads to a similar relative increase in CIN2/3 diagnosis to that found in women aged 30 to 49.

Detection and Outcome of Endocervical Atypia in Cytology in Primary HPV Screening Programme

Most endocervical adenocarcinomas (EAC) are associated with high-risk HPV (hrHPV) infection, with HPV genotypes 16, 18 and 45 accounting for >90% of the cases. Among endocervical glandular lesions, screening with hrHPV test has previously shown to predict the outcome better than cytology, although around one-fifth of the EAC remain negative both in hrHPV testing and cytology. The study consists of two consecutive HPV-primary screening rounds, conducted in 2012–2015 and 2017–2020. Of the 87 women aged 35 to 60 years of age diagnosed with Atypical endocervical cells, NOS or Atypical endocervical cells, favor neoplastic cytology during the first screening round, 63 (72.4%) were hrHPV positive and 24 (27.6%) were hrHPV negative. Among hrHPV positive patients, three EAC, two adenocarcinomas in situ (AIS), one AIS + high-grade intraepithelial lesion (HSIL) and 13 HSIL were found. Of the histologically verified lesions, 68.4% (13/19) were purely of squamous origin. All the EAC and AIS were HPV16 or HPV 18 positive. No high-grade histological lesions were found among the hrHPV negative patients with cytological glandular atypia. A later database search revealed one HPV-negative, gastric-type mucinous EAC that was missed by the HPV primary screening.

Lung cancer risk following previous abnormal chest radiographs: A 27-year follow-up study of a Chinese lung screening cohort.

Background Chest radiograph (CXR) is still one of the most commonly used diagnostic tools for chest diseases. In this cohort study, we attempted to investigate the magnitude and temporal pattern of lung cancer risk following abnormal CXR findings.MethodsWe conducted an extended follow‐up of an occupational screening cohort in Yunnan, China. The associations between abnormal CXR results from baseline screening, the first four consecutive rounds of CXR screening, all previous rounds of screening and lung cancer risk were analyzed using time‐varying coefficient Cox regression model. The associations of lung cancer risk and previous CXR‐screening results according to histology were also considered. Sensitivity analyses were conducted to assess the robustness of the previous abnormal CXR findings on subsequent lung cancer risk.ResultsAbnormal CXR findings were associated with a significantly increased lung cancer risk. This relative hazard significantly decreased over time. Compared to negative screening results, the adjusted hazard ratios (HR) of baseline abnormal CXR results, and at least one abnormal result in the first four consecutive screening rounds during the first 5 years of follow‐up were 17.06 (95% CI: 11.74–24.79) and 13.77 (95%: 9.58–17.79), respectively. This significantly increased lung cancer risk continued over the next 5 years. These associations were stronger for persistent abnormal findings, and abnormal findings identified in recent screening rounds.ConclusionsThe increased risk was significant for both squamous cell carcinoma and adenocarcinoma. Although decreased over time, an increased lung cancer risk relative to abnormal CXR findings can continue for 10 years.

Structure-Functional Analysis of Human Cytochrome P450 2C8 Using Directed Evolution.

The human genome includes four cytochrome P450 2C subfamily enzymes, and CYP2C8 has generated research interest because it is subject to drug–drug interactions and various polymorphic outcomes. To address the structure-functional complexity of CYP2C8, its catalytic activity was studied using a directed evolution analysis. Consecutive rounds of random mutagenesis and screening using 6-methoxy-luciferin produced two mutants, which displayed highly increased luciferase activity. Wild-type and selected mutants were expressed on a large scale and purified. The expression levels of the D349Y and D349Y/V237A mutants were ~310 and 460 nmol per liter of culture, respectively. The steady-state kinetic analysis of paclitaxel 6α-hydroxylation showed that the mutants exhibited a 5–7-fold increase in kcat values and a 3–5-fold increase in catalytic efficiencies (kcat/KM). In arachidonic acid epoxidation, two mutants exhibited a 30–150-fold increase in kcat values and a 40–110-fold increase in catalytic efficiencies. The binding titration analyses of paclitaxel and arachidonic acid showed that the V237A mutation had a lower Kd value, indicating a tighter substrate-binding affinity. The structural analysis of CYP2C8 indicated that the D349Y mutation was close enough to the putative binding domain of the redox partner; the increase in catalytic activity could be partially attributed to the enhancement of the P450 coupling efficiency or electron transfer.

Long-term Lung Cancer Risk Associated with Sputum Atypia: A 27-Year Follow-up Study of an Occupational Lung Screening Cohort in Yunnan, China.

Sputum cytologic atypia is associated with increased lung cancer risk. However, little is known about the long-term magnitude and temporal trend of this risk. An extended follow-up was conducted in a prospective screening cohort among occupational tin miners in Yunnan, China. Sputum samples were collected prospectively at baseline and 7 annual screenings since enrollment. The associations between sputum cytologic results from baseline screening, the first 4 consecutive rounds of sputum screening, and lung cancer risk were analyzed by time-varying covariate Cox regression model. A moderate or worse cytologic result was associated with a significantly increased lung cancer risk. This relative hazard significantly decreased over time. Compared with negative screening results, the adjusted hazard ratios of baseline-moderate or worse atypia, at least one moderate or worse atypia in the first 4 consecutive screening rounds during the first 10 years of follow-up were 3.11 [95% confidence interval (CI): 2.37-4.07], 3.25 (95% CI: 2.33-4.54) respectively. This association was stronger for persistent atypia (adjusted hazard ratio = 17.55, 95% CI: 8.32-37.03); atypia identified in the recent screening rounds (adjusted HR = 4.14, 95% CI: 2.70-6.35), and those were old in age, had higher level of smoking, occupational radon, and arsenic exposure. In terms of histology, this increased risk was significant for squamous cell carcinoma and small cell lung cancer. Although decreasing over time, an increased lung cancer risk concerning moderate or worse sputum atypia can continue at least for 10 years. Sputum atypia might be helpful for identifying high-risk individuals for screening, surveillance, or chemoprevention of lung cancer.

Sociodemographic features and patterns of non-participation in colorectal cancer screening in Finland

Colorectal cancer (CRC) screening was run as a randomized health services programme in Finland between 2004 and 2016. This study evaluates sociodemographic features and patterns of non-participation among men and women invited to be screened. The study population in this register-based study includes 233 211 men and women invited to guaiac faecal occult blood test screening on consecutive screening rounds (n = 708 621 invitations). A generalized estimating equation (GEE) was used to estimate incidence rate ratios (IRR) between sociodemographic features and non-participation. The overall proportion of non-participation was 31.6% and was higher in men (38.8%) than in women (24.6%). Birth cohort, education, marital status and country of birth were associated with non-participation. The birth cohort of 1950-54 was less likely to participate than the birth cohort of 1940-44. Men and women with primary education were more likely non-participants (IRR 1.26, CI 1.23-1.29 and IRR 1.22, CI 1.18-1.26, respectively) than men or women with tertiary education. Further, unmarried persons and immigrants had an increased risk of non-participation. Initial non-participation predicted subsequent behaviour, since, e.g. ∼80% of first-round non-participants also remained non-participants in the second round. Education, gender and marital status had a significant effect on non-participation in the CRC screening programme. As high and comprehensive participation is essential for a successful screening programme, attention should be paid in ensuring participation of all sociodemographic groups. Special efforts should be invested in those not participating in the first invitational round, since initial non-participation predicts non-participation to subsequent invitations.

Muscle mass heavily influences creatinine-based renal function estimation: a 12-year longitudinal general population-based cohort study

Abstract Muscle mass heavily influences creatinine-based renal function estimation: a 12-year longitudinal general population-based cohort study Background Current guidelines suggest the use of estimated glomerular filtration rate (eGFR) based on creatinine as measurement of renal function. However, the influence of muscle mass as key determinant of creatinine after renal function may render those estimates imprecise. Purpose To investigate the effects of 24-hour height-indexed creatinine excretion rate (CER index) – deemed an excellent marker of total muscle mass – on creatinine-based eGFR and to compare this with effects of CER index on muscle mass-independent cystatin C-based eGFR. Methods We included community-dwelling individuals aged 28–75 years enrolled in the prospective Prevention of REnal and Vascular ENd-stage Disease study. CER was assessed in paired 24-h urine specimens collected during five consecutive screening rounds, each round comprising two outpatient visits separated by three weeks. Cross-sectional and longitudinal associations were respectively quantified using linear regression and linear mixed-effects models, both of which were adjusted for sociodemographic and cardiovascular risk factors. Results Of the 7,698 individuals aged 49.8 (12.6) years, of whom 3,839 (49.9%) were male, baseline mean (SD) CER index was 7.0 (1.8) mmol/(24 h·m). Lower CER index was curvilinearly associated with higher creatinine-based eGFR and lower cystatin C-based eGFR (Figure 1). In a hypothetical 70-year-old male, assumed to have a CER index of 4 mmol/(24 h·m) (indicating low muscle mass), predicted creatinine-based eGFR and cystatin C-based eGFR were 79.8 and 64.1 (difference: 15.7) ml/min per 1.73 m2, respectively (Figure 1). If the CER index is held constant at 4 mmol/(24 h·m), the predicted ages at which the threshold of 60 ml/min per 1.73 m2 for the detection of chronic kidney disease would have been exceeded, were 84.7 years for creatinine-based eGFR and 72.7 years for cystatin C-based eGFR (difference: 12.0 years) (Figure 1). During 12.5 years of follow-up, CER index decreased with 0.21 (0.23) mmol/(24 h·m) per 10 years. For every 0.1 mmol/(24 h·m) annual decrease in CER index, creatinine-based eGFR increased with 0.16 (0.07 to 0.25; P=0.0004) ml/min per 1.73 m2 per year, whereas cystatin C-based eGFR decreased with 0.25 (0.15 to 0.34; P<0.0001) ml/min per 1.73 m2 after full adjustment. Conclusions Low muscle mass may cause considerable overestimation of single measurements of creatinine-based eGFR compared with cystatin C-based eGFR. Moreover, loss of muscle mass may cause spurious increases in repeatedly measured creatinine-based eGFR. Implementing muscle mass-independent markers for estimating renal function, like cystatin C, could provide a better alternative to accurately assess renal function in all settings wherein low muscle mass or muscle wasting may be encountered. Figure 1. Sex-specific 3D representation. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Dutch Kidney Foundation

Effect of artificial intelligence-based triaging of breast cancer screening mammograms on cancer detection and radiologist workload: a retrospective simulation study

We examined the potential change in cancer detection when using an artificial intelligence (AI) cancer-detection software to triage certain screening examinations into a no radiologist work stream, and then after regular radiologist assessment of the remainder, triage certain screening examinations into an enhanced assessment work stream. The purpose of enhanced assessment was to simulate selection of women for more sensitive screening promoting early detection of cancers that would otherwise be diagnosed as interval cancers or as next-round screen-detected cancers. The aim of the study was to examine how AI could reduce radiologist workload and increase cancer detection. In this retrospective simulation study, all women diagnosed with breast cancer who attended two consecutive screening rounds were included. Healthy women were randomly sampled from the same cohort; their observations were given elevated weight to mimic a frequency of 0·7% incident cancer per screening interval. Based on the prediction score from a commercially available AI cancer detector, various cutoff points for the decision to channel women to the two new work streams were examined in terms of missed and additionally detected cancer. 7364 women were included in the study sample: 547 were diagnosed with breast cancer and 6817 were healthy controls. When including 60%, 70%, or 80% of women with the lowest AI scores in the no radiologist stream, the proportion of screen-detected cancers that would have been missed were 0, 0·3% (95% CI 0·0-4·3), or 2·6% (1·1-5·4), respectively. When including 1% or 5% of women with the highest AI scores in the enhanced assessment stream, the potential additional cancer detection was 24 (12%) or 53 (27%) of 200 subsequent interval cancers, respectively, and 48 (14%) or 121 (35%) of 347 next-round screen-detected cancers, respectively. Using a commercial AI cancer detector to triage mammograms into no radiologist assessment and enhanced assessment could potentially reduce radiologist workload by more than half, and pre-emptively detect a substantial proportion of cancers otherwise diagnosed later. Stockholm City Council.

Screening outcome for consecutive examinations with digital breast tomosynthesis versus standard digital mammography in a population-based screening program.

To retrospectively investigate early performance measures of digital breast tomosynthesis (DBT) versus standard digital mammography (DM) for consecutive screening rounds. We included information about 35,736 women screened in BreastScreen Norway, 2008-2016, with at least two consecutive screening examinations. The pair of two consecutive screening examinations was the unit of analysis, and results from the subsequent examination were the measure of interest. Screening technique changed during the study period, resulting in four study groups: DM after DM, DBT after DM, DM after DBT, and DBT after DBT. We compared selected early performance measures between the study groups. Recall for DM after DM was 3.6% and lower for all other study groups (p < 0.001). The rate of screen-detected breast cancer was 4.6/1000 for DM after DM; for DBT after DM and DBT after DBT, it was 9.9/1000 and 8.3/1000, respectively (p < 0.001 relative to DM after DM), and for DM after DBT 4.3/1000. The rate of tubular carcinoma was higher for DBT after DBT or after DM compared with DM after DM (p < 0.01). The rate of histologic grade 1 tumors was higher for DBT after DM compared with DM after DM (p < 0.001). We did not observe any statistical difference in the interval cancer rates. Lower recall and higher cancer detection rates for screening with DBT were sustainable over two consecutive screening rounds. Positive predictive values were higher for DBT than DM. There were no differences in the interval cancer rates between the study groups. • There is limited knowledge about early performance measures for screening with digital breast tomosynthesis beyond one screening round. • A decline in recall rate and an incline in the rate of screen-detected breast cancer were observed for women screened with DBT compared with DM, irrespective of prior screening technique. The interval breast cancer rate did not differ statistically for women screened with DBT versus DM. • Tumor characteristics tended to be prognostic favorable for DBT compared with DM with no differences in rates of more advanced cancers. The clinical significance of increased cancer detection and the potential for future mortality reduction remain unknown.

Management of HPV‐positive women in cervical screening using results from two consecutive screening rounds

We studied whether triage of human papillomavirus (HPV)-positive women participating in an HPV-based screening programme can be improved by including the HPV result at the previous screen in the triage algorithm. We analyzed data of a subgroup of 366 women from the POBASCAM trial, screened by cytology and HPV cotesting. Women were included if they tested HPV-positive in the second HPV-based screening round. We evaluated the clinical performance of 16 strategies, consisting of cytology, HPV genotyping, and/or previous screen HPV result. The clinical endpoint was cervical precancer or cancer (CIN3+). The current Dutch triage testing policy for HPV-positive women is to refer women for colposcopy if they have abnormal cytology at baseline or after 6-18 months. In the second HPV-based screening round, this strategy yielded a negative predictive value (NPV) of 95.8% (95% confidence interval: 91.9-98.2) and colposcopy referral rate of 37.6% (32.3-43.2%). Replacing repeat cytology by the previous screen HPV result yielded a similar NPV (96.9%, 93.3-98.9) and colposcopy referral rate (38.8%, 33.4-44.4). A higher NPV (99.2%, 96.3-100%) at the cost of a higher colposcopy referral rate (49.2%, 43.6-54.8) was achieved when cytology was combined with HPV16/18 genotyping. The other 13 triage strategies yielded a lower NPV, a higher colposcopy referral rate or performed similarly but required additional testing. HPV-positive women in the second HPV-based screening round can be suitably managed by cytology, HPV16/18 genotyping and the HPV result at the previous screen, obviating the need for repeat testing of HPV-positive, cytology negative women.

Engineering thermal stability and solvent tolerance of the soluble quinoprotein PedE from Pseudomonas putida KT2440 with a heterologous whole-cell screening approach.

SummaryDue to their ability for direct electron transfer to electrodes, the utilization of rare earth metals as cofactor, and their periplasmic localization, pyrroloquinoline quinone‐dependent alcohol dehydrogenases (PQQ‐ADHs) represent an interesting class of biocatalysts for various biotechnological applications. For most biocatalysts protein stability is crucial, either to increase the performance of the protein under a given process condition or to maximize robustness of the protein towards mutational manipulations, which are often needed to enhance or introduce a functionality of interest. In this study, we describe a whole‐cell screening assay, suitable for probing PQQ‐ADH activities in Escherichia coli BL21(DE3) cells, and use this assay to screen smart mutant libraries for increased thermal stability of the PQQ‐ADH PedE (PP_2674) from Pseudomonas putida KT2440. Upon three consecutive rounds of screening, we identified three different amino acid positions, which significantly improve enzyme stability. The subsequent combination of the beneficial mutations finally results in the triple mutant R91D/E408P/N410K, which not only exhibits a 7°C increase in thermal stability but also a twofold increase in residual activity upon incubation with up to 50% dimethyl sulfoxide (DMSO), while showing no significant difference in enzymatic efficiency (k cat/KM).

Detection Rates of Ductal Carcinoma in Situ with Biennial Digital Mammography Screening: Radiologic Findings Support Pathologic Model of Tumor Progression.

Purpose To compare detection rates of ductal carcinoma in situ (DCIS), classified according to nuclear grade, between the prevalence round (baseline screening) and two subsequent screening rounds of a population-based digital mammography screening program, to assess differences over time. Materials and Methods The cancer registry provided data for 1970 graded pure DCIS cases from 16 screening regions of the prevalence round (baseline screening, from 2005 to 2008), first subsequent round, and second subsequent round; the interval between all screening rounds was 22-30 months. Age-adjusted logistic regression analysis was performed to compare the grade-specific detection rates between the prevalence round (reference) and subsequent screening rounds. Results Over all screening rounds, cancer detection rates were lowest for low-grade DCIS (range, 0.11 [58 of 508 817 patients] to 0.25 [178 of 713 867 patients] per 1000 women screened) and highest for high-grade DCIS (range, 0.53[271 of 508 817 patients] to 0.59 [237 of 398 944 patients] per 1000 women screened). Detection rates for low-grade DCIS were significantly lower in the first (odds ratio [OR] = 0.45, P < .001) and second (OR = 0.57, P < .001) subsequent screening rounds compared with that in the prevalence round; the relative reduction of detection rates of intermediate-grade DCIS was less pronounced (OR = 0.79, P = .006 and OR = 0.76, P = .003, respectively). Conversely, the detection rate of high-grade DCIS remained at the high level found in the prevalence screening (OR = 0.89, P = .143 and OR = 0.97, P = .700, respectively). Conclusion The findings demonstrate persistently high detection rates of high-grade DCIS in two consecutive subsequent screening rounds compared with the prevalence round; conversely, rates of low-grade DCIS and, less markedly, intermediate-grade DCIS decreased in subsequent rounds. Grade-related changes of DCIS detection are suggestive of distinct dynamics of lesion progression. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on November 10, 2017.

Initial participation as a predictor for continuous participation in population-based colorectal cancer screening.

To assess patterns and probabilities of participation in multiple rounds of colorectal cancer screening. All individuals who were invited to participate in population-based colorectal cancer screening in the Stockholm-Gotland region in Sweden between 1 January 2008 and 30 September 2015 were included in the study. Guaiac-based faecal occult blood testing was used. All individuals invited to the three first consecutive screening rounds were included in the analysis. There were 346,168 individuals eligible for invitation to screening. The average participation rate during the follow-up period was 60%. Eligible individuals could be invited 1-4 times, depending on age at first invitation. Of 48,959 individuals invited to the three first consecutive rounds of screening, 71% participated at least once, and 50% participated in all three rounds. Participation at first invitation was a predictor for participation in subsequent rounds, and the likelihood of continuous participation following participation in the first round was 84%. Of those who attended the first and second rounds, 93% also participated in the third round. Similar patterns of consistency were seen among non-participants. For individuals not participating in the first screening round, the likelihood of consistent non-participation was 71. Participation in the first round of screening is a strong predictor for participation in subsequent rounds. Therefore, reducing barriers for initial participation is a key for achieving consistent participation over several rounds in organized colorectal cancer screening programmes.

Mammographic density assessed on paired raw and processed digital images and on paired screen-film and digital images across three mammography systems.

BackgroundInter-women and intra-women comparisons of mammographic density (MD) are needed in research, clinical and screening applications; however, MD measurements are influenced by mammography modality (screen film/digital) and digital image format (raw/processed). We aimed to examine differences in MD assessed on these image types.MethodsWe obtained 1294 pairs of images saved in both raw and processed formats from Hologic and General Electric (GE) direct digital systems and a Fuji computed radiography (CR) system, and 128 screen-film and processed CR-digital pairs from consecutive screening rounds. Four readers performed Cumulus-based MD measurements (n = 3441), with each image pair read by the same reader. Multi-level models of square-root percent MD were fitted, with a random intercept for woman, to estimate processed–raw MD differences.ResultsBreast area did not differ in processed images compared with that in raw images, but the percent MD was higher, due to a larger dense area (median 28.5 and 25.4 cm2 respectively, mean √dense area difference 0.44 cm (95% CI: 0.36, 0.52)). This difference in √dense area was significant for direct digital systems (Hologic 0.50 cm (95% CI: 0.39, 0.61), GE 0.56 cm (95% CI: 0.42, 0.69)) but not for Fuji CR (0.06 cm (95% CI: −0.10, 0.23)). Additionally, within each system, reader-specific differences varied in magnitude and direction (p < 0.001). Conversion equations revealed differences converged to zero with increasing dense area. MD differences between screen-film and processed digital on the subsequent screening round were consistent with expected time-related MD declines.ConclusionsMD was slightly higher when measured on processed than on raw direct digital mammograms. Comparisons of MD on these image formats should ideally control for this non-constant and reader-specific difference.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-016-0787-0) contains supplementary material, which is available to authorized users.

Cribado del cáncer colorrectal

In the latest meeting of the American Gastroenterological Association, several clinical studies were presented that aimed to evaluate the various colorectal cancer screening strategies, although most assessed the various aspects of faecal immunochemical testing (FIT) and colonoscopy. Data were presented from consecutive FIT-based screening rounds, confirming the importance of adherence to consecutive screening rounds, achieving a similar or superior diagnostic yield to endoscopic studies. There was confirmation of the importance of not delaying endoscopic study after a positive result. Participants with a negative FIT (score of 0) had a low risk for colorectal cancer. Several studies seemed to confirm the importance of high-quality colonoscopy in colorectal cancer screening programmes. The implementation of high-quality colonoscopies has reduced mortality from proximal lesions and reduced interval cancers in various studies. Finally, participants with a normal colonoscopy result or with a small adenoma are at low risk for developing advanced neoplasms during follow-up.