Strategies to improve respiratory chemoreflex characterization by Duffin's rebreathing.

NEW FINDINGS: What is the central question of this study? We assessed the test-retest variability of respiratory chemoreflex characterization by Duffin's modified rebreathing method and explored whether signal averaging of repeated trials improves confidence in parameter estimation. What is the main finding and its importance? Modified rebreathing is a reproducible method to characterize responses of central and peripheral respiratory chemoreflexes. Signal averaging of multiple repeated tests minimizes within- and between-test variability, improves the confidence of chemoreflex characterization and reduces the minimal change in parameters required to establish an effect. Future experiments that apply this method might benefit from signal averaging to improve its discriminatory effect. ABSTRACT: We assessed the test-retest variability of central and peripheral respiratory chemoreflex characterization by Duffin's modified rebreathing method and explored whether signal averaging of repeated trials improves confidence in parameter estimation. Over four laboratory visits, 13 participants (mean ± SD age, 25 ± 5 years) performed six repetitions of modified rebreathing in isoxic-hypoxic conditions [end-tidal P O 2 ${P_{{{\rm{O}}_{\rm{2}}}}}$ ( P ET , O 2 ${P_{{\rm{ET,}}{{\rm{O}}_{\rm{2}}}}}$ )  = 50 mmHg] and isoxic-hyperoxic conditions ( P ET , O 2 ${P_{{\rm{ET,}}{{\rm{O}}_{\rm{2}}}}}$   = 150 mmHg). End-tidal P C O 2 ${P_{{\rm{C}}{{\rm{O}}_{\rm{2}}}}}$ ( P ET , C O 2 ${P_{{\rm{ET,C}}{{\rm{O}}_{\rm{2}}}}}$ ), P ET , O 2 ${P_{{\rm{ET,}}{{\rm{O}}_{\rm{2}}}}}$ and minute ventilation ( V ̇ $\dot {\rm V}$ E ) were measured breath-by-breath, by gas analyser and pneumotachograph. The V ̇ $\dot {\rm V}$ E versus P ET , C O 2 ${P_{{\rm{ET,C}}{{\rm{O}}_{\rm{2}}}}}$ relationships were fitted with a piecewise model to estimate the ventilatory recruitment threshold (VRT) and the slope above the VRT ( V ̇ $\dot {\rm V}$ E S). Breath-by-breath data from the three within- and between-day trials were averaged using two approaches [simple average (fit then average) and ensemble average (average then fit)] and compared with a single-trial fit. Variability was assessed by intraclass correlation (ICC) and coefficient of variance (CV), and the minimal detectable change was computed for each approach using two independent sets of three trials. Within days, the VRT and V ̇ $\dot {\rm V}$ E S exhibited excellent test-retest variability in both hyperoxic conditions (VRT: ICC = 0.965, CV = 2.3%; V ̇ $\dot {\rm V}$ E S: ICC = 0.932, CV = 15.5%) and hypoxic conditions (VRT: ICC = 0.970, CV = 2.9%; V ̇ $\dot {\rm V}$ E S: ICC = 0.891, CV = 17.2%). Between-day reproducibility was also excellent (hyperoxia, VRT: ICC = 0.930, CV = 2.2%; V ̇ $\dot {\rm V}$ E S: ICC = 0.918, CV = 14.2%; and hypoxia, VRT: ICC = 0.940, CV = 3.0%; V ̇ $\dot {\rm V}$ E S: ICC = 0.880, CV = 18.1%). Compared with a single-trial fit, there were no differences in VRT or V ̇ $\dot {\rm V}$ E S using the simple average or ensemble average approaches; however, ensemble averaging reduced the minimal detectable change for V ̇ $\dot {\rm V}$ E S from 2.95 to 1.39 L min-1  mmHg-1 (hyperoxia) and from 3.64 to 1.82 L min-1  mmHg-1 (hypoxia). Single trials of modified rebreathing are reproducible; however, signal averaging of repeated trials improves confidence in parameter estimation.

A comparison of nicotine content methods to produce a UPC2-MS2 method for the analysis of nicotine and minor alkaloids in SPECTRUM nicotine research cigarettes.

Nicotine is the principal alkaloid in tobacco and has been the primary subject of scientific investigation for its pharmacological effects contributing to tobacco use, dependence, withdrawal, and physical harm. Related minor alkaloids, accounting for less than 6% of alkaloid content in tobacco leaves, may also mirror some of the same pharmacological effects. To detect such low concentrations of the minor alkaloids, tobacco product methods produced by the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) using gas chromatography and flame ionization detection (GC-FID) have been adapted for use with gas chromatography-mass spectrometry (GC-MS). Nicotine and minor alkaloid content in SPECTRUM Nicotine Research Cigarettes (NRC) have previously been determined using GC-FID; however, the minor alkaloids were unable to be detected or quantitated. This study employed UltraPerformance Convergence Chromatography (UPC2) system coupled with tandem mass spectrometry (MS2) to determine the nicotine and minor alkaloid content in NRC tobacco products. CORESTA Recommended Methods (CRMs) were adapted for their sample preparative procedures for optimal extraction followed by detection with UPC2-MS2. These results were compared to two separate CRMs that used GC-FID and GC-MS2 as well as an alternative method with GC-MS2 detection. The GC-FID and GC-MS2 CRM preparations along with the alternative GC-MS2 were unable to detect the analytes in every NRC formulation, whereas the UPC2-MS2 extraction and detection method was able to quantify every analyte in every NRC formulation. This increased sensitivity demonstrates the utility of the UPC2-MS2 analytical method in accurately detecting and quantifying nicotine and minor alkaloids in tobacco filler.

Artemisinin-based combination therapy for uncomplicated Plasmodium falciparum malaria in Mali: a systematic review and meta-analysis.

BACKGROUND: Artemisinin-based combination therapy (ACT) was deployed in 2005 as an alternative to chloroquine and is considered the most efficacious treatment currently available for uncomplicated falciparum malaria. While widespread artemisinin resistance has not been reported to date in Africa, recent studies have reported partial resistance in Rwanda. The purpose of this study is to provide a current systematic review and meta-analysis on ACT at Mali study sites, where falciparum malaria is highly endemic. METHODS: A systematic review of the literature maintained in the bibliographic databases accessible through the PubMed, ScienceDirect and Web of Science search engines was performed to identify research studies on ACT occurring at Mali study sites. Selected studies included trials occurring at Mali study sites with reported polymerase chain reaction (PCR)-corrected adequate clinical and parasite response rates (ACPRcs) at 28 days. Data were stratified by treatment arm (artemether-lumefantrine (AL), the first-line treatment for falciparum malaria in Mali and non-AL arms) and analysed using random-effects, meta-analysis approaches. RESULTS: A total of 11 studies met the inclusion criteria, and a risk of bias assessment carried out by two independent reviewers determined low risk of bias among all assessed criteria. The ACPRc for the first-line AL at Mali sites was 99.0% (95% CI (98.3%, 99.8%)), while the ACPRc among non-AL treatment arms was 98.9% (95% CI (98.3%, 99.5%)). The difference in ACPRcs between non-AL treatment arms and AL treatment arms was not statistically significant (p = .752), suggesting that there are potential treatment alternatives beyond the first-line of AL in Mali. CONCLUSIONS: ACT remains highly efficacious in treating uncomplicated falciparum malaria in Mali. Country-specific meta-analyses on ACT are needed on an ongoing basis for monitoring and evaluating drug efficacy patterns to guide local malaria treatment policies, particularly in the wake of observed artemisinin resistance in Southeast Asia and partial resistance in Rwanda.

Risk of Heart Failure With Preserved Ejection Fraction in Older Women After Contemporary Radiotherapy for Breast Cancer.

BACKGROUND: Cardiomyocytes are resistant to radiation. However, cardiac radiation exposure causes coronary microvascular endothelial inflammation, a perturbation implicated in the pathogenesis of heart failure (HF) and particularly HF with preserved ejection fraction (HFpEF). Radiotherapy for breast cancer results in variable cardiac radiation exposure and may increase the risk of HF. METHODS: We conducted a population-based case-control study of incident HF in 170 female residents of Olmsted County, Minnesota (59 cases and 111 controls), who underwent contemporary (1998-2013) radiotherapy for breast cancer with computed tomography-assisted radiotherapy planning. Controls were matched to cases for age, tumor side, chemotherapy use, diabetes mellitus, and hypertension. Mean cardiac radiation dose (MCRD) in each patient was calculated from the patient's computed tomography images and radiotherapy plan. RESULTS: Mean age at radiotherapy was 69±9 years. Of HF cases, 38 (64%) had EF≥50% (HFpEF), 18 (31%) had EF<50% (HF with reduced EF), and 3 (5%) did not have EF measured. The EF was ≥40% in 50 of the 56 HF cases (89%) with an EF measurement. The mean interval from radiotherapy to HF was 5.8±3.4 years. The odds of HF was higher in patients with a history of ischemic heart disease or atrial fibrillation. The MCRD was 2.5 Gy (range, 0.2-13.1 Gy) and higher in cases (3.3±2.7 Gy) than controls (2.1±2.0 Gy; P=0.004). The odds ratio (95% confidence interval) for HF per log MCRD was 9.1 (3.4-24.4) for any HF, 16.9 (3.9-73.7) for HFpEF, and 3.17 (0.8-13.0) for HF with reduced EF. The increased odds of any HF or HFpEF with increasing MCRD remained significant after adjustment for HF risk factors and in sensitivity analyses matching by cancer stage rather than tumor side. Only 18.6% of patients experienced new or recurrent ischemic events between radiotherapy and the onset of HF. CONCLUSIONS: The relative risk of HFpEF increases with increasing cardiac radiation exposure during contemporary conformal breast cancer radiotherapy. These data emphasize the importance of radiotherapy techniques that limit MCRD during breast cancer treatment. Moreover, these data provide further support for the importance of coronary microvascular compromise in the pathophysiology of HFpEF.

Carbon loss from an unprecedented Arctic tundra wildfire.

Arctic tundra soils store large amounts of carbon (C) in organic soil layers hundreds to thousands of years old that insulate, and in some cases maintain, permafrost soils. Fire has been largely absent from most of this biome since the early Holocene epoch, but its frequency and extent are increasing, probably in response to climate warming. The effect of fires on the C balance of tundra landscapes, however, remains largely unknown. The Anaktuvuk River fire in 2007 burned 1,039 square kilometres of Alaska's Arctic slope, making it the largest fire on record for the tundra biome and doubling the cumulative area burned since 1950 (ref. 5). Here we report that tundra ecosystems lost 2,016 ± 435 g C m(-2) in the fire, an amount two orders of magnitude larger than annual net C exchange in undisturbed tundra. Sixty per cent of this C loss was from soil organic matter, and radiocarbon dating of residual soil layers revealed that the maximum age of soil C lost was 50 years. Scaled to the entire burned area, the fire released approximately 2.1 teragrams of C to the atmosphere, an amount similar in magnitude to the annual net C sink for the entire Arctic tundra biome averaged over the last quarter of the twentieth century. The magnitude of ecosystem C lost by fire, relative to both ecosystem and biome-scale fluxes, demonstrates that a climate-driven increase in tundra fire disturbance may represent a positive feedback, potentially offsetting Arctic greening and influencing the net C balance of the tundra biome.

Spatially Fractionated Radiation Therapy in Sarcomas: A Large Single-Institution Experience.

Purpose: Spatially fractionated radiation therapy (SFRT) is a recognized technique for enhancing tumor response in radioresistant and bulky tumors. We analyzed clinical and treatment outcomes in patients with bone and soft tissue sarcomas treated with modern SFRT techniques. Methods and Materials: Patients with metastatic or unresectable sarcoma treated with brass collimator, volumetric modulated arc therapy lattice, or proton SFRT from December 2019 to June 2022 were retrospectively reviewed. Consolidative external beam radiation therapy (EBRT) was delivered at the physician's discretion. Patient and treatment characteristics, treatment response (symptom improvement, local control, and imaging response), and toxicity data were collected. Results: The cohort consisted of 53 patients treated with 61 SFRT treatments. Median age at treatment was 60.0 years. The primary location was soft tissue in 46 courses (75%) and bone in 15 (25%). Fifty-three courses (87%) were treated for symptom relief. The most used SFRT technique was volumetric modulated arc therapy lattice (n = 52, 85%) to a dose of 20 Gy (n = 48, 79%; range, 16-20 Gy). EBRT was delivered post-SFRT in 55 (90%) treatment courses with a median time interval from SFRT to EBRT of 5 days (range, 0-14 days). Median physical EBRT dose and fractionation was 40 Gy (range, 9-73.5 Gy) and 10 fractions (range, 3-33 fractions). Median follow up was 7.4 months (range, 0.2-30 months). One-year overall survival and local control rates were 53% and 82%. Symptom relief was documented with 32 treatment courses (60%). Stable or partial response was observed with 47 treatment courses (90%). Four grade 3 to 4 acute and subacute toxicities were attributable to SFRT (8%). Conclusions: The current series is the largest to date documenting outcomes for SFRT in sarcomas. Our results suggest combined SFRT with EBRT is associated with a favorable toxicity profile and high rates of symptomatic and radiographic responses for metastatic or unresectable sarcomas.

Quantifying Improvement in V˙ o2peak and Exercise Thresholds in Cardiovascular Disease Using Reliable Change Indices.

PURPOSE: Improving aerobic fitness through exercise training is recommended for the treatment of cardiovascular disease (CVD). However, strong justifications for the criteria of assessing improvement in key parameters of aerobic function including estimated lactate threshold (θ LT ), respiratory compensation point (RCP), and peak oxygen uptake (V˙ o2peak ) at the individual level are not established. We applied reliable change index (RCI) statistics to determine minimal meaningful change (MMC RCI ) cutoffs of θ LT , RCP, and V˙ o2peak for individual patients with CVD. METHODS: Sixty-six stable patients post-cardiac event performed three exhaustive treadmill-based incremental exercise tests (modified Bruce) ∼1 wk apart (T1-T3). Breath-by-breath gas exchange and ventilatory variables were measured by metabolic cart and used to identify θ LT , RCP, and V˙ o2peak . Using test-retest reliability and mean difference scores to estimate error and test practice/exposure, respectively, MMC RCI values were calculated for V˙ o2 (mL·min -1. kg -1 ) at θ LT , RCP, and V˙ o2peak . RESULTS: There were no significant between-trial differences in V˙ o2 at θ LT ( P = .78), RCP ( P = .08), or V˙ o2peak ( P = .74) and each variable exhibited excellent test-retest variability (intraclass correlation: 0.97, 0.98, and 0.99; coefficient of variation: 6.5, 5.4, and 4.9% for θ LT , RCP, and V˙ o2peak , respectively). Derived from comparing T1-T2, T1-T3, and T2-T3, the MMC RCI for θ LT were 3.91, 3.56, and 2.64 mL·min -1. kg -1 ; 4.01, 2.80, and 2.79 mL·min -1. kg -1 for RCP; and 3.61, 3.83, and 2.81 mL·min -1. kg -1 for V˙ o2peak . For each variable, MMC RCI scores were lowest for T2-T3 comparisons. CONCLUSION: These MMC RCI scores may be used to establish cutoff criteria for determining meaningful changes for interventions designed to improve aerobic function in individuals with CVD.

A standardized approach to evaluate effectiveness of aerobic exercise training interventions in cardiovascular disease at the individual level.

BACKGROUND: Reliable change indices can determine pre-post intervention changes at an individual level that are greater than chance or practice effect. We applied previously developed minimal meaningful change (MMCRCI) scores for oxygen uptake (V̇O2) values associated with estimated lactate threshold (θLT), respiratory compensation point (RCP), and peak oxygen uptake (V̇O2peak) to evaluate the effectiveness of exercise training in cardiovascular disease patients. METHODS: 303 patients (65 ± 11 yrs.; 27% female) that completed a symptom-limited cardiopulmonary exercise test (CPET) before and after 6-months of guideline-recommended exercise training were assessed to determine absolute and relative V̇O2 at θLT, RCP, and V̇O2peak. Using MMCRCI ∆V̇O2 scores of ±3.9 mL·kg-1·min-1, ±4.0 mL·kg-1·min-1, and ± 3.6 mL·kg-1·min-1 for θLT, RCP, and V̇O2peak, respectively, patients were classified as "positive" (ΔθLT, ΔRCP, and/or ΔV̇O2peak ≥ +MMCRCI), "non-" (between ±MMCRCI), or "negative" responders (≤ -MMCRCI). RESULTS: Mean RCP (n = 86) and V̇O2peak (n = 303) increased (p < 0.05) from 19.4 ± 3.6 mL·kg-1·min-1 and 18.0 ± 6.3 mL·kg-1·min-1 to 20.1 ± 3.8 mL·kg-1·min-1 and 19.2 ± 7.0 mL·kg-1·min-1 at exit, respectively, whereas θLT (n = 140) did not change (15.5 ± 3.4 mL·kg-1·min-1 versus 15.7 ± 3.8 mL·kg-1·min-1, p = 0.324). For changes in θLT, 6% were classified as "positive" responders, 90% as "non-responders", and 4% as "negative" responders. For RCP, 10% exhibited "positive" changes, 87% were "non-responders", and 2% were "negative" responders. For ΔV̇O2peak, 57 patients (19%) were classified as "positive" responders, 229 (76%) as "non-responders", and 17 (6%) as "negative" responders. CONCLUSION: Most patients that completed the exercise training program did not achieve reliable improvements greater than that of chance or practice at an individual level in θLT, RCP and V̇O2peak.

Circulating tumor cells in metastatic breast cancer patients treated with immune checkpoint inhibitors - a biomarker analysis of the ALICE and ICON trials.

Immune checkpoint inhibitors (ICIs) have been introduced in breast cancer (BC) treatment and better biomarkers are needed to predict benefit. Circulating tumor cells (CTCs) are prognostic in BC, but knowledge is limited on CTCs in the context of ICI therapy. In this study, serial sampling of CTCs (CellSearch system) was evaluated in 82 patients with metastatic BC enrolled in two randomized trials investigating ICI plus chemotherapy. Programmed death-ligand 1 (PD-L1) expression on CTCs was also measured. Patients with ≥ 2 CTCs per 7.5 mL at baseline had gene expression profiles in tumor suggestive of increased T-cell activity, including increased tumor inflammation signature (TIS) in both triple-negative (P = 0.010) and hormone receptor-positive (P = 0.024) disease. Patients with luminal A BC had higher CTC levels. The association between CTC status and outcome was most apparent 4 weeks into therapy. PD-L1 expression in CTCs was observed in 6/17 CTC-positive patients and was associated with inferior survival. In conclusion, our study indicates that CTC numbers may inform on tumor immune composition, as well as prognosis. These findings suggest a potential of using CTCs as an accessible biomarker source in BC patients treated with immunotherapy.

Ipilimumab and nivolumab combined with anthracycline-based chemotherapy in metastatic hormone receptor-positive breast cancer: a randomized phase 2b trial.

BACKGROUND: Immune checkpoint inhibitors have shown minimal clinical activity in hormone receptor-positive metastatic breast cancer (HR+mBC). Doxorubicin and low-dose cyclophosphamide are reported to induce immune responses and counter regulatory T cells (Tregs). Here, we report the efficacy and safety of combined programmed cell death protein-1/cytotoxic T-lymphocyte-associated protein 4 blockade concomitant with or after immunomodulatory chemotherapy for HR+mBC. METHODS: Patients with HR+mBC starting first-/second- line chemotherapy (chemo) were randomized 2:3 to chemotherapy (pegylated liposomal doxorubicin 20 mg/m2 every second week plus cyclophosphamide 50 mg by mouth/day in every other 2-week cycle) with or without concomitant ipilimumab (ipi; 1 mg/kg every sixth week) and nivolumab (nivo; 240 mg every second week). Patients in the chemo-only arm were offered cross-over to ipi/nivo without chemotherapy. Co-primary endpoints were safety in all patients starting therapy and progression-free survival (PFS) in the per-protocol (PP) population, defined as all patients evaluated for response and receiving at least two treatment cycles. Secondary endpoints included objective response rate, clinical benefit rate, Treg changes during therapy and assessment of programmed death-ligand 1 (PD-L1), mutational burden and immune gene signatures as biomarkers. RESULTS: Eighty-two patients were randomized and received immune-chemo (N=49) or chemo-only (N=33), 16 patients continued to the ipi/nivo-only cross-over arm. Median follow-up was 41.4 months. Serious adverse events occurred in 63% in the immune-chemo arm, 39% in the chemo-only arm and 31% in the cross-over-arm. In the PP population (N=78) median PFS in the immune-chemo arm was 5.1 months, compared with 3.6 months in the chemo-only arm, with HR 0.94 (95% CI 0.59 to 1.51). Clinical benefit rates were 55% (26/47) and 48% (15/31) in the immune-chemo and chemo-only arms, respectively. In the cross-over-arm (ipi/nivo-only), objective responses were observed in 19% of patients (3/16) and clinical benefit in 25% (4/16). Treg levels in blood decreased after study chemotherapy. High-grade immune-related adverse events were associated with prolonged PFS. PD-L1 status and mutational burden were not associated with ipi/nivo benefit, whereas a numerical PFS advantage was observed for patients with a high Treg gene signature in tumor. CONCLUSION: The addition of ipi/nivo to chemotherapy increased toxicity without improving efficacy. Ipi/nivo administered sequentially to chemotherapy was tolerable and induced clinical responses. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT03409198.

Quality of life of advanced ovarian cancer patients in the randomized phase III study comparing primary debulking surgery versus neo-adjuvant chemotherapy.

OBJECTIVE: The EORTC 55971 trial compared primary debulking surgery (PDS) versus neo-adjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS). The impact of both treatment arms on quality of life (QOL) is reported. METHODS: Patients with stages IIIc or IV ovarian cancer completed the EORTC QLQ-C30 before treatment, at the third and sixth cycle of chemotherapy, and at 6- and 12-month follow-up. RESULTS: Data of 404 patients (N=201 PDS arm; N=203 IDS arm) were included in the QOL analysis. Between treatment arms no statistically significant differences were found in any of the QOL functioning scales. Patients showed a clinically relevant improvement (>10 points) on the global health/QOL, role functioning, emotional functioning and social functioning scales during and after treatment independent of the type of treatment. Clinically relevant differences from baseline to the follow-up assessments were noted for fatigue, pain, insomnia, appetite loss, constipation, diarrhea indicating symptom control in both treatment arms. Institutions with good QOL compliance were associated with better outcomes. There was a statistical significant difference in the overall debulking status with 39.9% optimal debulking surgery in institutions with good QOL compliance compared to 19.9% in institutions with poor QOL compliance (p=0.0011). Overall survival (median 32.30 versus 23.29 months; p=0.0006) and progression free survival (median 12.35 versus 9.92 months; p=0.0002) were also significantly better. CONCLUSIONS: Survival and QOL after NACT followed by surgery was similar to survival and QOL after PDS followed by chemotherapy. However, institutions with good QOL compliance had better survival outcomes.

Bristles formation in adhesive pads and sensilli of the gecko Tarentola mauritanica derive from a massive accumulation of corneous material in Oberhautchen cells of the epidermis.

Among lizards, geckos possess special digital scales modified as hairy-like lamellae that allow attachment to vertical substrates for the movement using adhesive nanoscale filaments called setae. The present study shows new ultrastructural details on setae formation in the gecko Tarentula mauritanica. Setae derive from the special differentiation of an epidermal layer termed Oberhauchen and can reach 30-60 µm in length. Oberhautchen cells in the adhesive pad lamellae becomes hypertrophic and rest upon 2 layers of non-corneous and pale cells instead of beta-cells like in the other scales. Only 1-2 beta-layers are formed underneath the pale layer. Setae derive from the accumulation of numerous roundish and heterogenous beta-packets with variable electron-density in Oberhautchen cells, possibly indicating a mixed protein composition. Immunofluorescence and immunogold labeling for CBPs show that beta-packets merge at the base of the growing setae forming long corneous bundles. Pale cells formed underneath the Oberhautchen layer contain small vesicles or tubules with a likely lipid content, sparse keratin filaments and ribosomes. In mature lamellae these cells merge with Oberhautchen and beta-cells forming a thin electron-paler layer located between the Oberhautchen and the thin beta-layer, a variation of the typical sequence of epidermal layers present in other scales. The formation of a softer pale layer and of a thin beta-layer likely determines a flexible corneous support for the adhesive setae. The specific molecular mechanism that stimulates the cellular changes observed during Oberhautchen hypertrophy and the alteration of the typical epidermal stratification in the pad epidermis remains unknown.

Micro-ornamentation patterns in different areas of the epidermis in the gecko Tarentola mauritanica reflect variations in the accumulation of corneous material in Oberhautchen cells.

Micro-ornamentations characterize the surface of scales in lepidosaurians and are summarized in four main patterns, i.e., spinulated, lamellated, lamellate-dentate, and honeycomb, although variations of these patterns are present in different species. Although geckos are known to possess a spinulated pattern derived from the Oberhautchen layer, also other pattern variations of the spinulated micro-ornamentation are present such as those indicated as dendritic ramification, corneous belts, and small bare patches. The present study mainly describes the variation of micro-ornamentations present in scales of different skin regions in the Mediterranean gecko Tarentula mauritanica using scannig and transmission electron microscopy. The study reports that the accumulation of corneous material in Oberhautchen cells is not homogenous in different areas of body scales and, when mature, this process gives rise to different sculpturing on the epidermal surface generating not only spinulae but also transitional zones leading to the other main patterns. It is hypothesized that spinulae formation derives from the vertical and lateral symmetric growth of tubercolate, non-overlapped scales of geckos. Sparse areas also result smooth or with serpentine-ridges likely revealing the beta-layer located underneath and merged with the Oberhautchen. The eco-functional role of this variable micro-ornamentation in the skin of lizards however remains largely speculative.

Do Clinical Exercise Tests Permit Exercise Threshold Identification in Patients Referred to Cardiac Rehabilitation?

BACKGROUND: To evaluate the feasibility of "threshold-based" aerobic exercise prescription in cardiovascular disease, we aimed to quantify the proportion of patients whose clinical cardiopulmonary exercise test (CPET) permit identification of estimated lactate threshold (θLT) and respiratory compensation point (RCP) and to characterize the variability at which these thresholds occur. METHODS: Breath-by-breath CPET data of 1102 patients (65 ± 12 years) referred to cardiac rehabilitation were analyzed to identify peak O2 uptake (V˙O2peak; mL·min-1 and mL·kg-1·min-1) and θLT and RCP (reported as V˙O2, %V˙O2peak, and %peak heart rate [%HRpeak]). Patients were grouped by the presence or absence of thresholds: group 0: neither θLT nor RCP; group 1: θLT only; and group 2: both θLT and RCP. RESULTS: Mean V˙O2peak was 1523 ± 627 mL·min-1 (range: 315-3789 mL·min-1) or 18.0 ± 6.5 mL·kg-1·min-1 (5.2-46.5 mL·kg-1·min-1) and HRpeak was 123 ± 24 beats per minute (bpm) (52 bpm-207 bpm). There were 556 patients (50%) in group 0, 196 (18%) in group 1, and 350 (32%) in group 2. In group 1, mean θLT was 1240 ± 410 mL·min-1 (580-2560 mL·min-1), 75% ± 8%V˙O2peak (52%-92%V˙O2peak), or 84% ± 6%HRpeak (64%-96%HRpeak). In group 2, θLT was 1390 ± 360 mL·min-1 (640-2430 mL·min-1), 70% ± 8%V˙O2peak (41%-88%V˙O2peak), or 78% ± 7%HRpeak (52%-96%HRpeak), and RCP was 1680 ± 440 mL·min-1 (730-3090 mL·min-1), 84% ± 7%V˙O2peak (54%-99%V˙O2peak), or 87% ± 6%HRpeak (59%-99%HRpeak). Compared with group 1, θLT in group 2 occurred at a higher V˙O2 but lower %V˙O2peak and %HRpeak (P < 0.05). CONCLUSIONS: Only 32% of CPETs exhibited both θLT and RCP despite flexibility in protocol options. Commonly used step-based protocols are suboptimal for "threshold-based" exercise prescription.

Clinical aspects of spatially fractionated radiation therapy treatments.

PURPOSE: To provide clinical guidance for centers wishing to implement photon spatially fractionated radiation therapy (SFRT) treatments using either a brass grid or volumetric modulated arc therapy (VMAT) lattice approach. METHODS: We describe in detail processes which have been developed over the course of a 3-year period during which our institution treated over 240 SFRT cases. The importance of patient selection, along with aspects of simulation, treatment planning, quality assurance, and treatment delivery are discussed. Illustrative examples involving clinical cases are shown, and we discuss safety implications relevant to the heterogeneous dose distributions. RESULTS: SFRT can be an effective modality for tumors which are otherwise challenging to manage with conventional radiation therapy techniques or for patients who have limited treatment options. However, SFRT has several aspects which differ drastically from conventional radiation therapy treatments. Therefore, the successful implementation of an SFRT treatment program requires the multidisciplinary expertise and collaboration of physicians, physicists, dosimetrists, and radiation therapists. CONCLUSIONS: We have described methods for patient selection, simulation, treatment planning, quality assurance and delivery of clinical SFRT treatments which were built upon our experience treating a large patient population with both a brass grid and VMAT lattice approach. Preclinical research and patient trials aimed at understanding the mechanism of action are needed to elucidate which patients may benefit most from SFRT, and ultimately expand its use.

Persistence of disseminated tumor cells after neoadjuvant treatment for locally advanced breast cancer predicts poor survival.

INTRODUCTION: Presence of disseminated tumor cells (DTCs) in bone marrow (BM) and circulating tumor cells (CTC) in peripheral blood (PB) predicts reduced survival in early breast cancer. The aim of this study was to determine the presence of and alterations in DTC- and CTC-status in locally advanced breast cancer patients undergoing neoadjuvant chemotherapy (NACT) and to evaluate their prognostic impact. METHODS: Bone marrow and peripheral blood were collected before NACT (BM1: n = 231/PB1: n = 219), at surgery (BM2: n = 69/PB2: n = 71), and after 12 months from start of NACT (BM3: n = 162/PB3: n = 141). Patients were included from 1997 to 2003 and followed until 2009 (or ten years follow-up). DTC- and CTC-status were determined by morphological evaluation of immunocytochemically detected cytokeratin-positive cells. The prognostic significance of DTCs/CTCs was assessed by univariate and multivariate Cox-regression analyses. RESULTS: Before NACT, DTCs and CTCs were detected in 21.2% and 4.9% of the patients, respectively. At surgery, 15.9% and 1.4% had DTC- and CTC-presence, compared to 26.5% and 4.3% at 12 months from start of NACT. Of patients for whom DTC results both before NACT and at 12 months were available, concordant results were observed in 68%, and 14 out of 65 had positive DTC-status at both time points. Presence of ≥ 1 DTC 12 months from start of NACT, but not at other time points, predicted reduced disease-free survival (DFS; HR 2.3, p = 0.003), breast cancer-specific survival (BCSS; HR 3.0, p < 0.001) and overall survival (OS; HR 2.8, p < 0.001). Before NACT, presence of ≥ 3 DTCs was also associated with unfavorable outcome, and reduced BCSS was observed for CTC-positive patients (HR 2.2, p = 0.046). In multivariate analysis, DTC status (

High-resolution analyses of copy number changes in disseminated tumor cells of patients with breast cancer.

The presence of disseminated tumor cells (DTCs) in bone marrow (BM) identifies breast cancer patients with less favorable outcome. Furthermore, molecular characterization is required to investigate the malignant potential of these cells. This study presents a single-cell array comparative genomic hybridization (SCaCGH) method providing molecular analysis of immunomorphologically detected DTCs. The resolution limit of the method was estimated using the cancer cell line SK-BR-3 on 44 and 244k arrays. The technique was further tested on 28 circulating tumor cells and four hematopoietic cells (HCs) from peripheral blood (n = 8 patients). The SCaCGH method was finally applied to 24 DTCs, three immunopositive cells morphologically classified as probable HCs from breast cancer patients and five HC controls from BM (n = 7 patients plus n = 1 healthy donor). The frequency of copy number changes of the DTCs revealed similarities with primary breast tumor samples. Three of the patients had available profiles for DTCs and the corresponding tumor tissue from primary surgery. More than two-third of the analyzed DTCs disclosed equivalent changes, both to each other and to the corresponding primary disease, whereas the rest of the cells showed balanced profiles. The probable HCs revealed either balanced profiles (n = 2) or changes comparable to the tumor tissue and DTCs (n = 1), indicating morphological overlap between HCs and DTCs. Similar aberration patterns were visible in DTCs collected at diagnosis and at 3 years relapse-free follow-up. SCaCGH may be a powerful tool for the molecular characterization of DTCs.

Thermal Degradants Identified from the Vaping of Vitamin E Acetate.

Studies have suggested that vitamin E acetate (VEA), when used in an electronic vaping device, undergoes thermal degradation and is considered one of the main contributors in e-cigarette or vaping product use-associated lung injury (EVALI). Using a Borgwaldt 5.1 linear smoker, a SVS250 Electronic Vaporizer and two types of tank systems, VEA was analyzed for degradation products produced via the Cooperation Centre for Scientific Research Relative to Tobacco method 81 when the filter containing vaporized VEA was extracted using acetonitrile. Two of the major products identified were 2,3,5,6-tetramethyl-1,4-benzoquinone and 2,6,10,14-tetramethyl-1-pentadecene, which were confirmed using analytical standards and gas chromatography-high-resolution mass spectrometry (GC-HRMS). Additional synthesis of 4-acetoxy-2,3,5,6-tetramethyl-2,4-cyclohexadienone and subsequent characterization using nuclear magnetic resonance and GC-HRMS suggested that this is not one of the products produced. Identification of these degradants will allow future studies to quantify and examine the degradants in vivo and in vitro as biomarkers for exposure and toxicity assessment.

VMAT Grid Therapy: A Widely Applicable Planning Approach.

PURPOSE: To describe a novel and practical volumetric modulated arc therapy (VMAT) planning approach for grid therapy. METHODS AND MATERIALS: Dose is prescribed to 1.5-cm diameter spherical contours placed throughout the gross tumor volume (GTV). Placement of spheres is variable, but they must maintain at least a 3-cm (center to center) separation, and the edge of any sphere must be at least 1 cm from any organ at risk (OAR). Three concentric ring structures are used during optimization to confine the highest doses to the center of the spheres and maximize dose sparing between them. The end result is alternating regions of high and low dose throughout the GTV and minimal dose to OARs. High-intensity flattening filter-free (FFF) modes are used to efficiently deliver the plans, and entire treatments typically take only 15 to 20 minutes. RESULTS: The approach is illustrated with 2 examples treated at our institution. Patient #1 had a 1703-cm3 mediastinal mass and was prescribed 20 Gray (Gy) to 24 spherical regions within the GTV. Patient #2 had a 3680-cm3 abdominal tumor and was prescribed 18 Gy to 32 spherical regions within the GTV. Both patients received additional consolidative radiation approximately 1 week after the initial VMAT grid treatment. Each patient experienced marked reduction in tumor size and symptomatic relief without treatment-related complications. CONCLUSIONS: We have described in detail a planning approach for VMAT grid therapy treatments that can typically be delivered in a clinically practical time span. The VMAT approach is especially useful for tumors that are surrounded by sensitive critical structures. As many centers offer VMAT treatments, the approach is widely accessible and can be readily implemented once appropriate patient selection and delivery processes are established.

Association of Clinical Outcomes With Surgical Repair of Hip Fracture vs Nonsurgical Management in Nursing Home Residents With Advanced Dementia.

Importance: The decision whether to surgically repair a hip fracture in nursing home (NH) residents with advanced dementia can be challenging. Objective: To compare outcomes, including survival, among NH residents with advanced dementia and hip fracture according to whether they underwent surgical hip fracture repair. Design, Setting, and Participants: We conducted a retrospective cohort study of 3083 NH residents with advanced dementia and hip fracture, but not enrolled in hospice care, using nationwide Medicare claims data linked with Minimum Data Set (MDS) assessments from January 1, 2008, through December 31, 2013. Methods: Residents with advanced dementia were identified using the MDS. Medicare claims were used to identify hip fracture and to determine whether the fracture was managed surgically. Survival between surgical and nonsurgical residents was compared using multivariable Cox proportional hazards with inverse probability of treatment weighting (IPTW). All analyses took place between November 2015 and January 2018. Among 6-month survivors, documented pain, antipsychotic drug use, physical restraint use, pressure ulcers, and ambulatory status were compared between surgical and nonsurgical groups. Results: Among 3083 residents with advanced dementia and hip fracture (mean age, 84.2 years; 79.2% female [n = 2441], 28.5% ambulatory [n = 879]), 2615 (84.8%) underwent surgical repair. By 6-month follow-up, 31.5% (n = 824) and 53.8% (n = 252) of surgically and nonsurgically managed residents died, respectively. After IPTW modeling, surgically managed residents were less likely to die than residents without surgery (adjusted hazard ratio [aHR], 0.88; 95% CI, 0.79-0.98). Among 2007 residents who survived 6 months, residents with surgical vs nonsurgical management had less docmented pain (29.0% [n = 465] vs 30.9% [n = 59]) and fewer pressure ulcers (11.2% [n = 200] vs 19.0% [n = 41]). In IPTW models, surgically managed residents reported less pain (aHR, 0.78; 95% CI, 0.61-0.99) and pressure ulcers (aHR, 0.64; 95% CI, 0.47-0.86). There was no difference between antipsychotic drug use and physical restraint use between the groups. Few survivors remained ambulatory (10.7% [n = 55] of surgically managed vs 4.8% [n = 1] without surgery). Conclusions and Relevance: Surgical repair of a hip fracture was associated with lower mortality among NH residents with advanced dementia and should be considered together with the residents' goals of care in management decisions. Pain and other adverse outcomes were common regardless of surgical management, suggesting the need for broad improvements in the quality of care provided to NH residents with advanced dementia and hip fracture.