Atrial natriuretic peptide (ANP): a study of ANP and its mRNA in cardiocytes,and of plasma ANP levels in non-obese diabetic mice

Summary Atrial natriuretic peptide (ANP) levels in cardiocytes and plasma were examined by using immunohistochemistry, electron microscopy, and radioimmunoassay in non-obese diabetic mice (NOD). Cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP immunoreactivity in the auricular cardiocytes was more prominent in hyperglycemic mice (NOD-h) than in normoglycemic mice (NOD-n). Ultrastructural examination showed that auricular cardiocytes of the NOD-h group contained more cytoplasmic granules than cells of the NOD-n group. Ultrastructural morphometry indicated that the number of granules per auricular cardiocyte was significantly larger in the NOD-h group than in the NOD-n group. (P<0.01), whereas the granule diameter was significantly smaller in the NOD-h group (P<0.01). Radioimmunoassay showed that ANP levels in the NOD-h auricular cardiocytes were significantly higher than those in the NOD-n cardiocytes (P<0.01); the opposite was true in plasma. Cardiocyte ANP mRNA expression was lower in the NOD-h group than in the NOD-n group.     

Quantification of fibroblast growth factor 23 and N-terminal pro-B-type natriuretic peptide to identify patients with atrial fibrillation using a high-throughput platform: A validation study

BackgroundLarge-scale screening for atrial fibrillation (AF) requires reliable methods to identify at-risk populations. Using an experimental semi-quantitative biomarker assay, B-type natriuretic peptide (BNP) and fibroblast growth factor 23 (FGF23) were recently identified as the most suitable biomarkers for detecting AF in combination with simple morphometric parameters (age, sex, and body mass index [BMI]). In this study, we validated the AF model using standardised, high-throughput, high-sensitivity biomarker assays.Methods and findingsFor this study, 1,625 consecutive patients with either (1) diagnosed AF or (2) sinus rhythm with CHA₂DS₂-VASc score of 2 or more were recruited from a large teaching hospital in Birmingham, West Midlands, UK, between September 2014 and February 2018. Seven-day ambulatory ECG monitoring excluded silent AF. Patients with tachyarrhythmias apart from AF and incomplete cases were excluded. AF was diagnosed according to current clinical guidelines and confirmed by ECG. We developed a high-throughput, high-sensitivity assay for FGF23, quantified plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) and FGF23, and compared results to the previously used multibiomarker research assay. Data were fitted to the previously derived model, adjusting for differences in measurement platforms and known confounders (heart failure and chronic kidney disease). In 1,084 patients (46% with AF; median [Q1, Q3] age 70 [60, 78] years, median [Q1, Q3] BMI 28.8 [25.1, 32.8] kg/m², 59% males), patients with AF had higher concentrations of NT-proBNP (median [Q1, Q3] per 100 pg/ml: with AF 12.00 [4.19, 30.15], without AF 4.25 [1.17, 15.70]; p < 0.001) and FGF23 (median [Q1, Q3] per 100 pg/ml: with AF 1.93 [1.30, 4.16], without AF 1.55 [1.04, 2.62]; p < 0.001). Univariate associations remained after adjusting for heart failure and estimated glomerular filtration rate, known confounders of NT-proBNP and FGF23. The fitted model yielded a C-statistic of 0.688 (95% CI 0.656, 0.719), almost identical to that of the derived model (C-statistic 0.691; 95% CI 0.638, 0.744). The key limitation is that this validation was performed in a cohort that is very similar demographically to the one used in model development, calling for further external validation.ConclusionsAge, sex, and BMI combined with elevated NT-proBNP and elevated FGF23, quantified on a high-throughput platform, reliably identify patients with AF.Trial registrationRegistry IRAS ID 97753 Health Research Authority (HRA), United Kingdom

Winnie Chua and colleagues identify and validate biomarkers for atrial fibrillation     

Polymorphisms associated with the risk of lung cancer in a healthy Mexican Mestizo population: Application of the additive model for cancer

Lung cancer is the leading cause of cancer mortality in Mexico and worldwide. In the past decade, there has been an increase in the number of lung cancer cases in young people, which suggests an important role for genetic background in the etiology of this disease. In this study, we genetically characterized 16 polymorphisms in 12 low penetrance genes (AhR, CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1, GSTPI, XRCC1, ERCC2, MGMT, CCND1 and TP53) in 382 healthy Mexican Mestizos as the first step in elucidating the genetic structure of this population and identifying high risk individuals. All of the genotypes analyzed were in Hardy-Weinberg equilibrium, but different degrees of linkage were observed for polymorphisms in the CYP1A1 and EPHX1 genes. The genetic variability of this population was distributed in six clusters that were defined based on their genetic characteristics. The use of a polygenic model to assess the additive effect of low penetrance risk alleles identified combinations of risk genotypes that could be useful in predicting a predisposition to lung cancer. Estimation of the level of genetic susceptibility showed that the individual calculated risk value (iCRV) ranged from 1 to 16, with a higher iCRV indicating a greater genetic susceptibility to lung cancer.     

Examining methodology to identify patterns of consulting in primary care for different groups of patients before a diagnosis of cancer: An exemplar applied to oesophagogastric cancer

BackgroundCurrent methods for estimating the timeliness of cancer diagnosis are not robust because dates of key defining milestones, for example first presentation, are uncertain. This is exacerbated when patients have other conditions (multimorbidity), particularly those that share symptoms with cancer. Methods independent of this uncertainty are needed for accurate estimates of the timeliness of cancer diagnosis, and to understand how multimorbidity impacts the diagnostic process.MethodsParticipants were diagnosed with oesophagogastric cancer between 2010 and 2019. Controls were matched on year of birth, sex, general practice and multimorbidity burden calculated using the Cambridge Multimorbidity Score. Primary care data (Clinical Practice Research Datalink) was used to explore population-level consultation rates for up to two years before diagnosis across different multimorbidity burdens. Five approaches were compared on the timing of the consultation frequency increase, the inflection point for different multimorbidity burdens, different aggregated time-periods and sample sizes.ResultsWe included 15,410 participants, of which 13,328 (86.5 %) had a measurable multimorbidity burden. Our new maximum likelihood estimation method found evidence that the inflection point in consultation frequency varied with multimorbidity burden, from 154 days (95 %CI 131.8–176.2) before diagnosis for patients with no multimorbidity, to 126 days (108.5–143.5) for patients with the greatest multimorbidity burden. Inflection points identified using alternative methods were closer to diagnosis for up to three burden groups. Sample size reduction and changing the aggregation period resulted in inflection points closer to diagnosis, with the smallest change for the maximum likelihood method.DiscussionExisting methods to identify changes in consultation rates can introduce substantial bias which depends on sample size and aggregation period. The direct maximum likelihood method was less prone to this bias than other methods and offers a robust, population-level alternative for estimating the timeliness of cancer diagnosis.     

The positive impact of cytological specimens for EGFR mutation testing in non‐small cell lung cancer: a single South East Asian laboratory’s analysis of 670 cases

B. Pang, D. Matthias, C.W. Ong, A.N. Dhewar, S. Gupta, G.L. Lim, M.‐E. Nga, J.E. Seet, A. Qasim, T.‐M. Chin, R. Soo, R. Soong and M. Salto‐Tellez The positive impact of cytological specimens for EGFR mutation testing in non‐small cell lung cancer: a single South East Asian laboratory’s analysis of 670 cases Objectives: To compare the rejection rates of non‐small cell lung cancer (NSCLC) samples obtained by differing sampling methods for testing by Sanger sequencing for epidermal growth factor receptor (EGFR) mutations. To assess the association between unsatisfactory outcomes and the quantity of DNA extracted from cytological versus histological samples. Methods: Six hundred and seventy NSCLC samples referred to our centre from 2008 to 2010 were reviewed as a consequence of sample rejection, presence of EGFR mutations, cytological versus histological sampling methods, DNA quantity and the unsatisfactory genotyping rate. Results: Eighty samples were rejected for testing in similar proportions of histological and cytological samples (11.9% versus 10.9%) usually (n = 75) because the amount of cellular material was judged insufficient in small biopsies or cytology samples. The remaining 590 samples on which EGFR testing was attempted yielded 51 (8.6%) unsatisfactory test outcomes caused by failure of the polymerase chain reaction (PCR) (n = 47 cases), uninterpretable Sanger chromatograms (n = 3 cases) and insufficient DNA extracted for PCR (n = 1 case). The difference in rates of unsatisfactory outcomes between cytological samples (seven of 147 samples or 4.7%) versus tissue samples (44 of 443 samples or 9.9%) was clinically relevant but not statistically significant (Mann–Whitney test; P < 0.081). There was no association between the concentration of DNA extracted and the likelihood of an unsatisfactory analysis; which was similar in all types of sections (large and small) while 0% of 37 cytology slides were unsatisfactory. Conclusions: Utilizing cytology samples for EGFR testing avoids unnecessary patient re‐biopsing and yields a clinically superior satisfactory rate to the overall satisfactory rate of tissue biopsies of NSCLC. The quality rather than quantity of DNA extracted may be a more important determinant of a satisfactory result.     

Apatinib for heavily treated patients with non-small cell lung cancer: Report of a case series and literature review

Although many strategies have been developed for non-small cell lung cancer (NSCLC), more secondary and further treatments are needed due to drug resistance or tumor recurrence. Apatinib is a novel oral antiangiogenic agent and in this study, we aim to investigate the clinical value of apatinib in heavily pretreated NSCLC. Here, we reported the characteristics, efficacy and adverse events of three patients treated with apatinib (500?mg/day). We also summarized the currently available evidence and ongoing clinical trials regarding the use of apatinib in NSCLC. Two cases of adenocarcinoma and one case of squamous cell carcinoma were treated with apatinib due to disease progression after previous treatments of chemotherapy and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI). All patients responded to apatinib rapidly and underwent drug resistance shortly afterwards. The patient with squamous cell carcinoma died of hemoptysis. Other adverse events were acceptable. All previous relevant studies were compared and showed similar results but a longer progression-free survival. Additionally, ongoing clinical trials were systematically searched and listed. In conclusion, apatinib shows some efficacy in heavily treated NSCLC and generally tolerable toxicity in non-squamous NSCLC. More solid evidence will be accessible in near future.     

Probability of lung cancer in a population excluded from screening due to low PLCOM2012 risk

BackgroundSeveral randomized trials demonstrated have reduced lung cancer mortality with screening using computed tomography. However, there remains debate about the optimal approach for determining screening eligibility, and no evidence yet exists reporting lung cancer rates in those excluded from screening due to too low of a personalized risk.MethodsThis study was based on the Alberta Lung Cancer Screening Study, which received 1737 applicants and enrolled 850 based on the NLST criteria or a PLCO_M2012 risk ≥ 1.5%. We excluded 887 applicants who were interested in screening but deemed ineligible. We report lung cancer rates in the screened and unscreened cohorts.ResultsWe observed 30 and 8 lung cancers in the screened and unscreened groups, respectively. Only 1 of 8 lung cancers were among those considered too low risk (0.14%), while the remaining 7 were among those excluded for other reasons, including symptoms requiring more immediate workup. No NLST eligible but PLCO risk < 1.5% screened individual had a lung cancer detected as part of the study, so that of all applicants contacting the program with risk estimates less than 1.5%, only 1/857 (0.12%) developed lung cancer.ConclusionOur findings indicate that a risk-based approach for screening eligibility is unlikely to miss many lung cancers.