Rational thresholding of circulating tumor DNA concentration for improved surveillance of metastatic breast cancer.

BACKGROUND: The use of circulating tumor DNA (ctDNA) concentration for metastatic cancer surveillance is promising, but uncertainty remains about cut-offs with clinical validity. MATERIALS AND METHODS: This observational study recruited 136 subjects with advanced metastatic breast cancer (irrespective of ERBB2/hormone receptor status) for sequencing of their primary tumor in search for PIK3CA hotspot variants amenable for monitoring by droplet digital PCR (ddPCR). The study analyzed 341 on-treatment samples from 19 patients with PIK3CA variants H1047R or E545K enrolled for long-term (median 85 weeks, range 13-125 weeks), frequent (every 3-5 weeks, median of 14 time points per subject, range 2-29) blood sampling for ctDNA quantification by ddPCR, orthogonally validated by deep sequencing. The diagnostic accuracy of ctDNA versus cancer antigen 15-3 (CA15-3) concentrations to predict disease progression within 12 weeks was investigated using receiver operating characteristic (ROC) analysis. Likelihood ratios were used for rational selection of ctDNA result intervals. RESULTS: ctDNA [area under the ROC curve (AUC) 0.848, 95% confidence interval (CI) 0.791-0.895] showed superior diagnostic performance than CA15-3 (AUC 0.670, 95% CI 0.601-0.735, P < 0.001) to predict clinical progression within 12 weeks. ctDNA levels below 10 mutant allele copies/ml had high negative predictive value (88%), while levels above 100 copies/ml detected 64% of progressions 10 weeks earlier versus standard of care. Logistic regression analysis indicated complementary value of ctDNA and the presence of two consecutive CA15-3 rises, resulting in a model with 86% (95% CI 74% to 93%) positive predictive value and a clinically meaningful result in 89% of blood draws. CONCLUSIONS: Intensive ctDNA quantification improves metastatic breast cancer surveillance and enables individualized risk-based scheduling of clinical care.

Prevalence of Bordetella holmesii and Bordetella bronchiseptica in respiratory tract samples from Belgian patients with pertussis-like symptoms by sensitive culture method and mass spectrometry.

Insertion sequences IS481 and IS1001 are targets for molecular detection of respectively Bordetella pertussis and Bordetella parapertussis. There is a raising concern about specificity of these targets due to sequence similarity with Bordetella holmesii and Bordetella bronchiseptica. The likelihood of false (para)pertussis diagnoses should be correlated with the prevalence of these organisms in the respiratory tract (RT). From October 2010 until September 2011, 2,207 RT samples were submitted to the Belgian reference laboratory for pertussis diagnosis. End-point IS481/IS 1001 PCR and culture were performed for B. pertussis and B. parapertussis. We developed a sensitive culture method followed by screening with matrix-assisted laser desorption/ionisation- time of flight mass spectrometry (MALDI-TOF MS) to look for B. holmesii and B. bronchiseptica in our samples,. Only one B. bronchiseptica and no B. holmesii were detected in RT samples from Belgian patients with pertussis-like symptoms.

Optimization of the coherence measurement computed by means of the Welch averaged periodogram method for assessment of impaired cerebral autoregulation.

The coherence method (COH) has been widely used to study the concordance between continuously measured signals intervening in the assessment of cerebral autoregulation in neonates. Several research groups have applied this method to mean arterial blood pressure (MABP) combined with cerebral signals such as the intravascular oxygenation (HbD), cerebral tissue oxygenation (TOI), and regional oxygen saturation (rSO(2)) measured by near-infrared spectroscopy (NIRS). All groups contributed in a particular way to the fine-tuning of the application of COH with the Welch averaged periodogram (WAP) method. We have made a comparative study of all published results coupled with an optimization of the use of the WAP method within COH. We have also proposed a pre-processing algorithm to remove signal artefacts, and defined a new critical score value (CSV) for COH to distinguish infants with impaired autoregulation from those without.

The partial coherence method for assessment of impaired cerebral autoregulation using near-infrared spectroscopy: potential and limitations.

The most important forms of brain injury in premature infants are partly caused by disturbances in cerebral autoregulation. As changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO(2)), and cerebral tissue oxygenation (TOI) reflect changes in cerebral blood flow (CBF), impaired autoregulation can be measured by studying the concordance between HbD/rSO(2)/TOI and the mean arterial blood pressure (MABP), assuming no changes in oxygen consumption, arterial oxygen saturation (SaO(2)), and in blood volume. We investigated the performance of the partial coherence (PCOH) method, and compared it with the coherence method (COH). The PCOH method allows the elimination of the influence of SaO(2) on HbD/rSO(2)/TOI in a linear way. We started from long-term recordings measured in the first days of life simultaneously in 30 infants from three medical centres. We then compared the COH and PCOH results with patient clinical characteristics and outcomes, and concluded that PCOH might be a better method for assessing impaired autoregulation.

Molecularly imprinted solid-phase extraction of fumonisin B analogues in bell pepper, rice and corn flakes.

A molecularly imprinted polymer (MIP) for the recognition of fumonisin B analogues (FB) using 2-(diethylamino) ethyl methacrylate (DEAEM) as functional monomer and trimethylolpropane trimethacrylate (TRIM) as cross-linker was prepared by bulk polymerization in acetonitrile. Fumonisin B(1) (FB(1)) was used as a template molecule. A molecularly imprinted solid-phase extraction (MISPE) procedure was developed for further application in the analysis of FB. The performance of the MIP throughout the clean-up of spiked bell pepper, rice and corn flake sample extracts was compared with the results obtained when using non-imprinted polymer, C(18), strong anion exchange and immunoaffinity sorbents. Extracts were analysed for FB with liquid chromatography-tandem mass spectrometry (LC-MS/MS) after clean-up. Depending on the food matrix and the concentration range of the fumonisins, recoveries after MISPE varied from 62 to 86%, from 62 to 83%, and from 67 to 81% for fumonisin B(1) (FB(1)), fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)), respectively. The selectivity of the synthesized MIP for mycotoxins belonging to the group of FB was confirmed by evaluating cross-reactivity from analogue structures and other mycotoxins. Analysis of 39 naturally contaminated samples (corn flakes) by liquid chromatography tandem mass spectrometry indicated that the synthesized MIP could be an excellent alternative for clean-up and pre-concentration of FB in food samples. Pearson correlations between immunoaffinity clean-up and MISPE were calculated and amounted to 0.923 for FB(1), 0.808 for FB(2), and 0.759 for FB(3). It was shown that the developed MIP could be reused more than 50 times. The synthesis of an FB(1) imprinted polymer and its application in food analysis is reported for the first time.

Surgical closure of the patent ductus arteriosus and its effect on the cerebral tissue oxygenation.

AIM: Surgical patent ductus arteriosus (PDA) ligation is considered after failure or contraindication of medical treatment. Till now ligation of the PDA has been associated with low morbidity and mortality although recently concerns have been raised about the possible association of ductal clipping and neurodevelopmental abnormalities later in life. By means of near-infrared spectroscopy (NIRS), we analysed the changes in the cerebral tissue oxygenation index (TOI) and fractional tissue oxygen extraction (FTOE) at the time of clipping as well as after clipping. METHOD: Ten preterm infants with a symptomatic PDA who underwent surgical ligation were continuously monitored for heart rate (HR), mean arterial blood pressure (MABP), peripheral oxygen saturation (SaO(2)) and TOI from 1 h before up to 1 h after clipping. FTOE and haemoglobin difference (HbD) were calculated. Changes in parameters at 5 min after ligation represent the effect of the clipping itself whereas changes up to 1 h-post-clipping represent the post-clipping effect. RESULTS: At the exact time of clipping, over the entire group, we found a significant increase in TOI of 2.9% (p = 0.037), in HbD of 12.5 micromol/l (p = 0.047) and in HR of 6.5 bpm (p = 0.012). FTOE significantly decreased by 0.02% (p = 0.013). One hour post-clipping, the cerebral and peripheral parameters were not significantly different from the control values before clipping. CONCLUSION: The ductal clipping in se has no negative effect on the cerebral oxygenation.

Adiponectin levels do not predict clinical onset of type 1 diabetes in antibody-positive relatives.

AIMS/HYPOTHESIS: Insulin resistance has been proposed as a risk factor for type 1 diabetes. We investigated whether adiponectin, an insulin sensitiser, can serve as an additional predictive marker for type 1 diabetes in first-degree relatives of known patients. METHODS: Adiponectin was followed in 211 persistently islet antibody-positive (Ab+) first-degree relatives of type 1 diabetic patients and in 211 age- and sex-matched persistently antibody-negative relatives, and correlated with antibody status, random proinsulin:C-peptide ratio and HLA-DQ genotype. During follow-up, 37 Ab+ relatives developed type 1 diabetes. RESULTS: In the group of 422 relatives, baseline adiponectin correlated inversely with age and BMI and was lower in male than in female participants, especially after 15 years of age (p < 0.001). There was no correlation with antibody status or later development of diabetes. In 24 Ab+ relatives sampled fasted, adiponectin levels correlated significantly with homeostasis model assessment of insulin sensitivity (p = 0.006). In Ab+ relatives (n = 211), adiponectin levels could not predict type 1 diabetes nor complement risk assessment based on islet antibodies, HLA-DQ genotype and pancreatic hormones in Cox regression analysis. CONCLUSIONS/INTERPRETATION: Adiponectin levels do not contribute to the prediction of type 1 diabetes in Ab+ relatives.

D-901 neonatal oxygenator: a new perspective.

Five infants with congenital heart disease were perfused with the D-901 neonatal oxygenator at the time of their cardiac surgery. The ability to reduce the prime volume below the blood volume as well as the blood handling and gas transfer characteristics were studied. In all cases the prime volume was less than or equal to the blood volume of the patient. This resulted in a reduction in the use of homologous blood products. Due to the concept of the D-901 it was possible to adapt the tubing in such a way that a complete prime of 220 ml was obtained. The device had a maximum oxygen transfer of 45 ml/min. The maximum carbon dioxide removal was 50 ml/min at a blood gas ratio of one. The mean platelet count post bypass decreased to 91% of the baseline value. Mean free haemoglobin levels increased to 86 mg/100 ml at 120 minutes of bypass. We conclude that the D-901 oxygenator opens new perspectives for perfusion in small babies in terms of priming volume and use of homologous blood products while maintaining good gas transfer characteristics. However, larger series are necessary to expand our experience with this device and its limitations. No specific problems related to the device were encountered and all infants had an uneventful postoperative course.

Clinical evaluation of a new hollow fibre membrane oxygenator.

Twelve consecutive patients undergoing elective cardiac surgery were perfused with the Cobe Optima hollow fibre oxygenator. Gas transfer characteristics and blood handling were studied. The device had a maximum oxygen transfer of 315 ml/minute. The average shunt fraction was 4.5%, and was not influenced by blood-flow rate. Mean platelet count declined slightly to 91% of the baseline at the end of the study period. Haemolysis was evaluated by monitoring serum-free haemoglobin, serum haptoglobin and serum haemopexin. The evolution was as follows: free haemoglobin increased from 14 +/- 5 mg/100 ml to 85 +/- 0.8/100 ml (p = 0.01) at the end of bypass; haptoglobin decreased from 1.33 +/- 0.90 g/l to 0.89 +/- 0.15 g/l (p = 0.01); and haemopexin decreased from 0.84 +/- 0.13 g/l to 0.74 +/- 0.15 g/l (p = nonsignificant). In all patients the residual capacity of serum haptoglobin to protect against haemolysis was satisfactory. All patients had an uneventful postoperative course.

Assessment of anti-HLA antibodies in sera being tested for platelet reactivity by a platelet lymphocyte immunofluorescence test (PLIFT).

An indirect immunofluorescence test using a platelet mononuclear cell suspension is described. The test is a simple and sensitive method to assess the contamination by anti-HLA antibodies of sera being tested for platelet reactivity and eliminates the need to support two independent test systems such as lymphocytotoxicity and immunofluorescence testing. The test could be of value in routine platelet serology testing and platelet crossmatching.

Reflection from an oriented biaxial surface.

Analytic expressions for the amplitude reflection and transmission coefficients for light incident on a biaxial anisotropic material are presented for the special case where one of the principal axes of the material is parallel to the surface of the material. It is assumed that either the material or the light source can be oriented so that the principal axis that is parallel to the surface is also perpendicular to the plane of incidence of the light.

HLA-DR and monoclonal gammopathy.

The frequencies of the HLA-DR antigens were compared in 3 groups: a group of 33 patients with multiple myeloma (MM) or Morbus Waldenström (MW): a group of 34 persons with benign monoclonal gammopathy (BMG); and a group of 118 healthy controls. No statistically significant associations were observed.