Unraveling the potential clinical utility of circulating tumor DNA detection in colorectal cancer-evaluation in a nationwide Danish cohort

BACKGROUND

Increasingly, circulating tumor DNA (ctDNA) is proposed as a tool for minimal residual disease (MRD) assessment. Digital PCR (dPCR) offers low analysis costs and turnaround times of less than a day, making it ripe for clinical implementation. Here, we used tumor-informed dPCR for ctDNA detection in a large colorectal cancer (CRC) cohort to evaluate the potential for post-operative risk assessment and serial monitoring, and how the metastatic site may impact ctDNA detection. Additionally, we assessed how altering the ctDNA-calling algorithm could customize performance for different clinical settings.

PATIENTS AND METHODS

Stage II-III CRC patients (N = 851) treated with a curative intent were recruited. Based on whole-exome sequencing on matched tumor and germline DNA, a mutational target was selected for dPCR analysis. Plasma samples (8 ml) were collected within 60 days after operation and-for a patient subset (n = 246)-every 3-4 months for up to 36 months. Single-target dPCR was used for ctDNA detection.

RESULTS

Both post-operative and serial ctDNA detection were prognostic of recurrence [hazard ratio (HR) = 11.3, 95% confidence interval (CI) 7.8-16.4, P < 0.001; HR = 30.7, 95% CI 20.2-46.7, P < 0.001], with a cumulative ctDNA detection rate of 87% at the end of sample collection in recurrence patients. The ctDNA growth rate was prognostic of survival (HR = 2.6, 95% CI 1.5-4.4, P = 0.001). In recurrence patients, post-operative ctDNA detection was challenging for lung metastases (4/21 detected) and peritoneal metastases (2/10 detected). By modifying the cut-off for calling a sample ctDNA positive, we were able to adjust the sensitivity and specificity of our test for different clinical contexts.

CONCLUSIONS

The presented results from 851 stage II-III CRC patients demonstrate that our personalized dPCR approach effectively detects MRD after operation and shows promise for serial ctDNA detection for recurrence surveillance. The ability to adjust sensitivity and specificity shows exciting potential to customize the ctDNA caller for specific clinical settings.

Effects of bilateral lung transplantation on cardiac autonomic modulation and cardiorespiratory coupling: a prospective study

Background

Although cardiac autonomic modulation has been studied in several respiratory diseases, the evidence is limited on lung transplantation, particularly on its acute and chronic effects. Thus, we aimed to evaluate cardiac autonomic modulation before and after bilateral lung transplantation (BLT) through a prospective study on patients enrolled while awaiting transplant.

Methods

Twenty-two patients on the waiting list for lung transplantation (11 women, age 33 [24–51] years) were enrolled in a prospective study at Ospedale Maggiore Policlinico Hospital in Milan, Italy. To evaluate cardiac autonomic modulation, ten minutes ECG and respiration were recorded at different time points before (T0) and 15 days (T1) and 6 months (T2) after bilateral lung transplantation. As to the analysis of cardiac autonomic modulation, heart rate variability (HRV) was assessed using spectral and symbolic analysis. Entropy-derived measures were used to evaluate complexity of cardiac autonomic modulation. Comparisons of autonomic indices at different time points were performed.

Results

BLT reduced HRV total power, HRV complexity and vagal modulation, while it increased sympathetic modulation in the acute phase (T1) compared to baseline (T0). The HRV alterations remained stable after 6 months (T2).

Conclusion

BLT reduced global variability and complexity of cardiac autonomic modulation in acute phases, and these alterations remain stable after 6 months from surgery. After BLT, a sympathetic predominance and a vagal withdrawal could be a characteristic autonomic pattern in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01752-6.

Co-divergence and tree topology

In reconstructing the common evolutionary history of hosts and parasites, the current method of choice is the phylogenetic tree reconciliation. In this model, we are given a host tree H, a parasite tree P, and a function [Formula: see text] mapping the leaves of P to the leaves of H and the goal is to find, under some biologically motivated constraints, a reconciliation, that is a function from the vertices of P to the vertices of H that respects [Formula: see text] and allows the identification of biological events such as co-speciation, duplication and host switch. The maximum co-divergence problem consists in finding the maximum number of co-speciations in a reconciliation. This problem is NP-hard for arbitrary phylogenetic trees and no approximation algorithm is known. In this paper we consider the influence of tree topology on the maximum co-divergence problem. In particular we focus on a particular tree structure, namely caterpillar, and show that-in this case-the heuristics that are mostly used in the literature provide solutions that can be arbitrarily far from the optimal value. Then, we prove that finding the max co-divergence is equivalent to compute the maximum length of a subsequence with certain properties of a given permutation. This equivalence leads to two consequences: (1) it shows that we can compute efficiently in polynomial time the optimal time-feasible reconciliation and (2) it can be used to understand how much the tree topology influences the value of the maximum number of co-speciations.

Automatic procedures for the synthesis of difficult peptides using oxyma as activating reagent: A comparative study on the use of bases and on different deprotection and agitation conditions

Solid-Phase Peptide Synthesis (SPPS) is a rapid and efficient methodology for the chemical synthesis of peptides and small proteins. However, the assembly of peptide sequences classified as "difficult" poses severe synthetic problems in SPPS for the occurrence of extensive aggregation of growing peptide chains which often leads to synthesis failure. In this framework, we have investigated the impact of different synthetic procedures on the yield and final purity of three well-known "difficult peptides" prepared using oxyma as additive for the coupling steps. In particular, we have comparatively investigated the use of piperidine and morpholine/DBU as deprotection reagents, the addition of DIPEA, collidine and N-methylmorpholine as bases to the coupling reagent. Moreover, the effect of different agitation modalities during the acylation reactions has been investigated. Data obtained represent a step forward in optimizing strategies for the synthesis of "difficult peptides".

[Therapeutic education of elderly patients under antivitamin - K treatment: evaluation of the program after 5 years]

INTRODUCTION

Elderly people with vitamin K antagonists (VKA) have a higher risk of potentially serious hemorrhagic complications. An education program for patients (EPP) aged > or = 75 years with VKA was set up in 2008 in a French geriatric hospital. It includes individual and group sessions conducted by a nurse and a geriatrician.

OBJECTIVES

The aim of this study was to assess this EPP after 5 years. Strengths, weaknesses and difficulties of implementation were highlighted, and some improvements were proposed.

METHODS

This study is an external audit conducted by a pharmacist trained in EPP. Files of consecutive patients included in the program between may 2008 and March 2013 were reviewed allowing the data collection of patients characteristics and results of the different sessions. The educational objectives were assessed by the rate of correct responses to the questionnaires during the program. The results are presented taking into account the changes made during the 5 years of the program.

RESULTS

One hundred forty-three patients, mean age 83.3 +/- 6.5 years, were included in the EPP. 51 sessions were conducted (2.8 patients/session on average). 58% of selected patients were hospitalized. The mean time between the start of anticoagulant treatment and the incLusion in the program was 48.9 +/- 71 months. For 95 patients (66.4%) the medication management at home required a caregiver who was present for sessions in 82 cases (57.3%). The questionnaires form and the organisation of the sessions were gradually improved between 2008 and the end of 2010. Thus, the impact of the EPP has been estimated from November 2010 to March 2013. The correct responses rates before and after the sessions were respectively: 47.8% vs 91.3% for knowledge of INR target values, 25.4% vs 91.3% for knowledge of hemorrhagic signs, 14.9% vs 87.0% for knowledge of the situations or the medications that may disturb the INR equilibrium. Furthermore, the mean number of correct responses, for the 23 patients participating in the entire program, is statistically different between the educational diagnostic and immediate evaluation (3.7/7 vs 5.4/7 p = 0.023) and no significant difference is observed between immediate and distant evaluation (5.4/7 vs 5.8/7 p = 0.720).

CONCLUSION

An improvement of patient knowledge was observed with regard to the main educational objectives. Some improvements are proposed: to disseminate information to general practitioners, to add the follow up of INR values to assess an impact on anticoagulant treatment stability. Furthermore, this program is now adapted to the new oral anticoagulants. It is the role of hospital or community pharmacists to initiate and/or assess this type of EPP.

[Relationship between maintenance dosages of fluindione (Préviscan) and warfarin (Coumadin) for patients 70 years and older]

INTRODUCTION

Switching from fluindione, an indanedione vitamin K antagonist derivative, to warfarin, a coumarin one, or vice versa, requires to know the relationships between dosages of these two molecules.

METHODS

We conducted a prospective study in 288 consecutive patients aged 70 years and over, converted from fluindione to warfarin. Patients who were retained for the analysis were those for whom maintenance dosages were obtained for both vitamin K antagonists.

RESULTS

Eighty-two patients, mean aged 83 ± 6 years, were analysed. The average daily maintenance dosages were 13.8 ± 6.7 mg (range 5-35) and 3.7 ± 1.7 mg (range 1-8) for fluindione and warfarin, respectively. Using a linear regression model, we built a transition algorithm for the maintenance dosages of warfarin and fluindione.

CONCLUSION

This is the first study to propose a conversion algorithm to help prescribers to estimate the maintenance dosage when it is necessary for a patient to switch from fluindione to warfarin or conversely.

Assessment of efficacy and safety of pandemic A/H1N1/2009 influenza vaccine in a group of health care workers

INTRODUCTION

The development in an extremely short time of an efficacious and safe vaccine against the pandemi A/H1N1 virus was a challenge that involved the entire scientific community.

AIMS

To assess the immunological and clinical efficacy of the new H1N1v monovalent influenza vaccine (Focetria Novartis Vaccines, Siena, Italy) in a group of health care workers (HCWs).

METHODS

A total of 148 volunteer HCWs were enrolled between Mid-Novembre 2009 and December 2009. After measuring antibody titers, a single intramuscular dose of 7.5 microg of Focetria monovalent vaccine against A/H1N1/2009 influenza virus with MF59C.1 adjuvant was administered.

RESULTS

Antibody titers (median value) before and after a single dose of vaccine, measured by means of standard beam-agglutination inhibition test (HAI), increased from 32 to 256 (p < 0.001). After vaccination, 79.7% of the subjects showed antibody seroconversion, and in 97.3% seroprotection was achieved. The ratio between the geometric means of antibody titers (GMTR) was 6.69. For the 3 subjects who reported symptoms of ILI (Influenza-like illness), a regular nasal-pharyngeal swab sample was taken to identify the virus type by RT-PCR, the laboratory results of tests performed on these samples were negative for pandemic A/H1N1/2009 virus. During the entire follow-up period of 6 months no severe adverse events occurred.

CONCLUSIONS

The vaccine against pandemic A/H1N1/2009 virus provided protection against the virus and not only contributed to a significant immunization (according to EMEA criteria), but kept all 148 subjects under study free from A/H1N1/2009 influenza illness.

Late rectal bleeding after 3D-CRT for prostate cancer: development of a neural-network-based predictive model

The aim of this study was to develop a model exploiting artificial neural networks (ANNs) to correlate dosimetric and clinical variables with late rectal bleeding in prostate cancer patients undergoing radical radiotherapy and to compare the ANN results with those of a standard logistic regression (LR) analysis. 718 men included in the AIROPROS 0102 trial were analyzed. This multicenter protocol was characterized by the prospective evaluation of rectal toxicity, with a minimum follow-up of 36 months. Radiotherapy doses were between 70 and 80 Gy. Information was recorded for comorbidity, previous abdominal surgery, use of drugs and hormonal therapy. For each patient, a rectal dose-volume histogram (DVH) of the whole treatment was recorded and the equivalent uniform dose (EUD) evaluated as an effective descriptor of the whole DVH. Late rectal bleeding of grade ≥ 2 was considered to define positive events in this study (52 of 718 patients). The overall population was split into training and verification sets, both of which were involved in model instruction, and a test set, used to evaluate the predictive power of the model with independent data. Fourfold cross-validation was also used to provide realistic results for the full dataset. The LR was performed on the same data. Five variables were selected to predict late rectal bleeding: EUD, abdominal surgery, presence of hemorrhoids, use of anticoagulants and androgen deprivation. Following a receiver operating characteristic analysis of the independent test set, the areas under the curves (AUCs) were 0.704 and 0.655 for ANN and LR, respectively. When evaluated with cross-validation, the AUC was 0.714 for ANN and 0.636 for LR, which differed at a significance level of p = 0.03. When a practical discrimination threshold was selected, ANN could classify data with sensitivity and specificity both equal to 68.0%, whereas these values were 61.5% for LR. These data provide reasonable evidence that results obtained with ANNs are superior to those achieved with LR when predicting late radiotherapy-related rectal bleeding. The future introduction of patient-related personal characteristics, such as gene expression profiles, might improve the predictive power of statistical classifiers. More refined morphological aspects of the dose distribution, such as dose surface mapping, might also enhance the overall performance of ANN-based predictive models.

Treatment efficacy of language and calculation disorders and speech apraxia: a review of the literature

The aim of the study was to evaluate the efficacy of the treatment for language and calculation disorders and for speech apraxia in vascular subjects. Only therapeutic methods that could be qualified as neuropsychological were taken into account. For language disorders, we searched the pertinent literature published from 1950 to August 31, 2007 by means of electronic data banks and we took into consideration the Cochrane review, and papers in Cicerone et al. and Cappa et al. systematic reviews. For acalculia we examined the literature from 1980 by carrying out research on electronic data banks; for speech apraxia, studies emerged from a search of PUBMED. Aphasia therapy has been clearly demonstrated efficacious in groups of subjects if sufficiently prolonged/intensive. Treatment for specific disorders (words and sentences processing, reading, writing) studied in series of single patients, though always efficacious, reaches a lower level of recommendation due to the lack of RCT. Only a few studies tackled the problem of efficacy in case of speech apraxia and calculation disorders. Results are positive but data are scanty. Efficacy of aphasia therapy seems well established in group of subjects and well-promising for speech apraxia and calculation disorders. It is suggested, however, that the term "aphasia" covers widely different impairments and that RCT are not the best instrument to evaluate efficacy; the importance of chronicity is underlined.

Long-term productivity of lowland and upland switchgrass cytotypes as affected by cutting frequency

A considerable number of studies has been conducted on switchgrass (Panicum virgatum L.) as a bioresource for energy over the last few years. Nonetheless, some important issues concerning the agro-technique are still open. This research examines the long-term total dry matter yield (TDM) and ash content of two lowland (L) and two upland (U) switchgrass cytotypes, as affected by one or two-cut system, under southern EU climatic conditions (44 degrees 33' N). Overall, L produced higher TDM than U (on average 14.9 and 11.7 Mg ha(-1), respectively); two-cut system allowed to produce higher biomass yields (especially in U) than single harvest during the two first years, but it also drastically reduced plant vigour and productivity of all cytotypes in the following two years. Moreover, under two-cut system almost total seasonal biomass derived from the early harvest, while the second cut slightly contributed to the total seasonal biomass, nor it appeared to offset the additional harvest costs. Biomass quality was also significantly affected by cutting frequency, with two-cut system leading to a considerably higher ash content of biomass. Therefore, it is perceived that two-cut system is not worthwhile with U and L cytotypes as bioresource for energy production under southern EU conditions.

Improved naming after transcranial direct current stimulation in aphasia

Transcranial direct current stimulation (tDCS) has been proposed as an adjuvant technique to improve functional recovery after ischaemic stroke. This study evaluated the effect of tDCS over the left frontotemporal areas in eight chronic non-fluent post-stroke aphasic patients. The protocol consisted of the assessment of picture naming (accuracy and response time) before and immediately after anodal or cathodal tDCS (2 mA, 10 minutes) and sham stimulation. Whereas anodal tDCS and sham tDCS failed to induce any changes, cathodal tDCS significantly improved the accuracy of the picture naming task by a mean of 33.6% (SEM 13.8%).

A set of nomograms predicting acute gastrointestinal syndrome after prostate cancer conformal radiation

15555

Background: To predict acute toxicities (tox) of the gastrointestinal syndrome (SOMA LENT) in prostate cancer (PCa) patients (pts) undergoing 3D-CRT using a tool (nomogram) with clinical as well as dosimetric variables which has proved to be significant in the AIROPROS 01–02 trial. Methods: Acute rectal tox was scored in 1,132 pts using a 10 item self assessed questionnaire (QST) describing radio-induced GI symptoms profiles for bowel frequency, tenesmus, fecal continence, rectal pain and bleeding. The correlation between hormonal therapy (HT), drug prescription, diabetes or hypertension, pelvic node or seminal vesicles irradiation, mean rectal dose, DVH constraints and rectal tox was investigated by uni- and multivariate (MVA) logistic analyses. MVA results were used the R-project software to create nomograms predicting the symptoms of the acute GI syndrome. Results: 4/10 items of the QST are reported: moderate/severe bleeding, increased bowel frequency, moderate/severe bowel urgency and severe fecal incontinence. Bleeding is related to haemorrhoids (OR=1.9), HT (protective factor, OR=0.78) and mean rectal dose (continuous variable (cv), OR=1.024). Bowel frequency is related to seminal vesicles irradiation (OR=2.8) and V60 (cv, OR=1.024), while bowel urgency is correlated to seminal vesicles irradiation (OR=3.3) and mean rectal dose (cv, OR=1.027). Fecal incontinence depends on seminal vesicles irradiation (OR=4.6) and V70 (cv, OR=1.029). MVA results were used to create a set of nomograms. Conclusions: The combined effect of several independent, prognostically valuable variables for a specific disease can be expressed using nomograms. They can evaluate clinical and technical parameters of the single pt and offer clinicians a tailored probability of a specific outcome. To our best knowledge, this work presents the first set of nomograms available in the literature specific symptoms of the GI syndrome. The prediction capability of these tools will be validated on a independent set of patients. This work was partly supported by Fondazione I. Monzino, Milan

No significant financial relationships to disclose.

[Femoropopliteal arterial thrombosis in a young patient with heterozygous V Leiden factor mutation. Case report]

Activated C protein resistance is a common coagulation defect caused by factor V Leiden mutation and is associated with an augmented risk of predominantly venous thrombosis. Augmented tendency to arterial thrombosis is sporadically reported. This case report describes femoropopliteal thrombosis in a young patient with heterozygous V Leiden factor mutation. Progressive thrombotic occlusion required amputation of the forefoot which resulted in stump dehiscence. Poor blood supply to the perilesional substrate delayed wound healing. An optimal though not yet definitive result was achieved after months of accurate medication. The criticality of lower limb ischemia in an otherwise healthy young patient underscores the grave impact this condition can have on the patient's quality of life and on health care costs.

The effect of transient and continuous drought on yield, photosynthesis and carbon isotope discrimination in sugar beet (Beta vulgaris L.)

Stable carbon isotope discrimination (delta13C), photosynthetic performance (A), dry matter accumulation (DW), and sucrose yield (Y(s)) of sugar beet were evaluated in a glasshouse experiment under transient (TS) and permanent (PS) water stress. A was significantly reduced under drought, to an extent depending on stress duration. The reduced A was strictly associated with a low DW and Y(s), the later being 42% lower in PS than control plants (C). Restoring water steeply increased A and the associated leaf traits (RWC, leaf water potential etc.), but the increase of Y(s) was negligible. Therefore, the negative effects of severe water stress in the early growth period, though reversible on gas-exchange and most leaf traits, can drastically reduce Y(s) of sugar beet. Furthermore, A seems not to be effective in predicting sucrose accumulation, although it was very effective in detecting the occurrence of plant water stress. The A/C(i) model was used to assess the photosynthetic adjustments to continuous or transient drought by calculating the photosynthetic parameters Vcmax and Jmax and then compared with delta13C. Mesophyll conductance (g(m)) was estimated by comparing delta13C measured on soluble sugars and gas-exchange data. This approach confirmed the expectation that g(m) was limiting A and that there was a significant drop in [CO2] from the substomatal cavities and the chloroplast stroma both in favourable and drought conditions. Therefore, the carbon concentration at the carboxylation site was overestimated by 25-35% by conventional gas-exchange measurements, and Vcmax was consistently underestimated when g(m) was not taken into account, especially under severe drought. Root delta13C was found to be strictly related to sucrose content (brix%), Y(s) and root dry weight, and this was especially clear when delta13C was measured on bulk dry matter. By contrast, leaf delta13C measured in soluble sugars (delta(s)) and bulk dry matter (delta(dm)) were found to correlate weakly to brix% and yield, and this was not surprising as the integration time-scale of leaf delta(s) and delta(dm) were found to be shorter than that of root delta13C in bulk dry matter. The effect of water stress on diffusive and biochemical limitations with different integration times ranged from 1 d (leaf delta(s)) to more than 1 month (root delta(dm)).

Transcoronary sinus administration of autologous bone marrow in patients with chronic refractory stable angina Phase 1

PURPOSE

Based on our preclinic studies with autologous unfractionated bone marrow (AUBM) via coronary sinus with transitory occlusion, a clinic study in patients with chronic stable angina was designed. The objectives were to evaluate safety, tolerance and feasibility.

METHODS AND MATERIALS

A multicenter prospective study with inclusion and exclusion criteria defined by an Independent Clinical Committee was carried out. Fourteen patients underwent transcoronary sinus administration of freshly aspirated and filtered AUBM (60-120 ml). Safety and tolerance were evaluated. Feasibility was evaluated with Seattle Angina Questionnaire (SAQ), Canadian Cardiovascular Society (CCS) angina classification (baseline-Day 180), myocardial perfusion (baseline-Day 90) with independent core laboratory and coronary angiography (baseline and Day 30).

RESULTS

There were no changes in the safety and tolerance parameters. Preliminary clinical efficacy at Day 180 disclosed a significant improvement of 38%, evaluated by the SAQ. The CCS angina classification shows that the mean angina class was 3.0+/-0.55 at baseline and improved to 2.0+/-0.00 at Day 180 (P <.001). Semiquantitative radionuclide perfusion imaging (core lab) showed a significant improvement at Day 90 in 13/14 patients, with a mean improvement of 24% at rest (P <.01) and 33% at stress (P <.05). Coronary angiography showed more collateral vessels in 9/14 patients.

CONCLUSIONS

We can conclude that AUBM via coronary sinus with transitory occlusion is tolerable and safe. Significant improvement in the myocardial perfusion at Day 90 and in the quality of life at Day 180 was observed.

The importance of aquatic and terrestrial habitat for the European pond turtle (Emys orbicularis): implications for conservation planning and management

The European pond turtle, Emys orbicularis (L., 1758), is threatened throughout its distribution, prompting management of habitats and populations for conservation. Quantitative data on habitat requirements for this species are needed to better evaluate which areas are the most suitable, or what actions can improve habitat suitability. We studied relationships between the distribution and abundance of E. orbicularis and the environment by analysing water quality and features of 39 wetland and upland habitats in the Po River delta of northern Italy; visual transects and point counts were used to determine turtle presence and relative abundance. Emys orbicularis occurs more frequently and abundantly in permanent wetlands surrounded by woodlands, and its presence does not appear to be related to water eutrophication. Woodlands strongly influence adjacent wetland features and may be important for turtles' terrestrial activities such as nesting and dispersal. Habitat management and conservation plans for E. orbicularis should include protection of extensive terrestrial woodland habitat containing diverse wetland systems, to support turtle survival at different life-history stages. The requirements for wetlands and natural terrestrial habitat are difficult to meet in the currently human-dominated European lowlands; nevertheless, conservation plans for this species should take a broad-scale approach.

Difficulties in maintaining long-term partial nitritation of ammonium-rich sludge digester liquids in a moving-bed biofilm reactor (MBBR)

Nitrogen can be eliminated effectively from sludge digester effluents by anaerobic ammonium oxidation (anammox), but 55-60% of the ammonium must first be oxidized to nitrite. Although a continuous flow stirred tank reactor (CSTR) with suspended biomass could be used, its hydraulic dilution rate is limited to 0.8-1 d(-1) (30 degrees C). Higher specific nitrite production rates can be achieved by sludge retention, as shown here for a moving-bed biofilm reactor (MBBR) with Kaldnes carriers on laboratory and pilot scales. The maximum nitrite production rate amounted to 2.7 gNO2-Nm(-2)d(-1) (3 gO2m(-3)d(-1), 30.5 degrees C), thus doubling the dilution rate compared to CSTR operation with suspended biomass for a supernatant with 700 gNH4-Nm(-3). Whenever the available alkalinity was fully consumed, an optimal amount of nitrite was produced. However, a significant amount of nitrate was produced after 11 months of operation, making the effluent unsuitable for anaerobic ammonium oxidation. Because the sludge retention time (SRT) is relatively long in biofilm systems, slow growth of nitrite oxidizers occurs. None of the selection criteria applied - a high ammonium loading rate, high free ammonia or low oxygen concentration - led to selective suppression of nitrite oxidation. A CSTR or SBR with suspended biomass is consequently recommended for full-scale operation.

Cardiorespiratory system dynamics in chronic heart failure

AIMS

With the complex demodulation (CDM) method, we assessed the instantaneous amplitude and frequency of cardiovascular (CV) and respiratory oscillations, and the instant phase (IP) between the CV and respiratory signals using respiration as a periodic forced stimulation. We hypothesised a possible lack of synchronisation between CV and respiratory signals under regular breathing at different frequencies.

METHODS

RR interval (ECG), blood pressure (SBP/DBP, Finapress), respiration (Respitrace) were monitored during two random-order periods of voluntary paced-breathing (0.15 Hz/0.25 Hz) in 10 moderate CHF patients and 10 age-matched controls. The CDM method provides the amplitude and frequency of a particular spectral component as a function of time in both LF and HF bands. IP between CV and respiratory oscillations was assessed using the real modulating breathing rate.

RESULTS

(i) Continuous phase variations between CV oscillations and the respiratory signal were evidenced in CHF patients, the slower the breathing rate, the greater the phase variation (RR/Resp; 0.25 Hz, 23+/-17 degrees; 0.15 Hz, 46+/-57 degrees, P<0.01; RR/Resp at 0.15 Hz 6+/-3 vs. 46+/-57 P<0.01 controls vs. CHF). Phase was constant in controls. (ii) In patients, the instant amplitude of the cardiovascular oscillations in the high frequency domain is more markedly altered when the breathing rate was slowed down as compared to controls.

CONCLUSION

The lack of synchronisation between physiological signals during voluntary breathing in CHF patients highlights a central uncoupling between CV and respiratory neuronal activities.

Autonomic control of the cardiovascular system during sleep in normal subjects

The autonomic control of heart rate and blood pressure during sleep is controversial: although it has been reported that vagal activity is more often lower in rapid eye movement sleep (REM) than in other stages of sleep (non-REM, NREM), the opposite has also been described. Initially, it was reported that baroreflex sensitivity (BRS) increases during sleep (REM and NREM), but in later studies, this was only partially confirmed. We therefore studied autonomic control of the cardiovascular (CV) system during sleep in 12 normal adults. The spectral components of the heart rate R-R interval, blood pressure (BP), and BRS were computed at low (LF) and actual breathing frequency (high frequency, HF). Analysis of sleep stage and a cycle-by-cycle stage II analysis were performed. CV variability is affected largely by sleep-stage and sleep-cycle organisation: NREM and the last cycle exhibit the greatest vagal activity and the lowest sympathetic activity. BRS estimation for both the LF and HF bands confirmed previous results obtained by pharmacological and spontaneous slope methods: BRS is greater during sleep than during nocturnal wake periods, and further increased in REM. BRS is frequency dependent: in NREM, the higher value of HF BRS compared to LF BRS favours the HF control of BP variability, whereas higher BRS HF and LF components contribute to the strongest control in REM. BRS variability exhibits no significant pattern during the night. Our results suggest that both sleep-cycle organisation and BRS estimation in the LF and HF bands should be considered in sleep studies of autonomic CV control.

Transcoronary sinus delivery of autologous bone marrow and angiogenesis in pig models with myocardial injury

PURPOSE

The aim of the investigation is to study myocardial injury on pig model with two objectives: (1) feasibility of stimulating angiogenesis with fresh autologous bone marrow; (2) administration of the same fresh autologous bone marrow via coronary sinus with transitory occlusion.

METHODS

A controlled study was done in animal model with three phases, in a study group of 12 pigs (bone marrow administration) as well as in control group of 4 pigs (saline administration). Phase 1-production of coronary stenosis and myocardial injury; Phase 2-two weeks later, administration of bone marrow through coronary sinus with 10 min occlusion in the study group and saline solution in the control group. Phase 3-two weeks later, histological staining with hematoxylin-eosin and inmunohistochemical staining with monoclonal antibody for smooth muscle alpha-actin were conducted on both study and control groups.

RESULTS

The percentage of angionenesis observed in the study group was 91% and 0% in control group. Counting of positive actin in affected and control areas showed statistically significant differences in relation to both groups: study group (1.37 vs. 0.79) and control group (0.47 vs. 0.51). The percentage of mononuclear immature cells observed in the myocardium in the study group was 25% and in the control group was 0%. There was no increment in the coronary collateral circulation when comparing coronary angiography.

CONCLUSIONS

Autologous bone marrow in animal model with experimental myocardial injury enhances angiogenesis, as well as vessels with smooth muscles. The transitory occlusion of the coronary sinus might be an effective way to administer cells as those from the bone marrow.

[Obstructive sleep apnea syndrome and heart failure]

Heart failure has an increasing prevalence in middle age adults. The prognosis is very poor even with improved medical therapy and heart transplants. The outcome is related to the neurohumoral disease resulting from heart failure which leads to sympathetic activation that in turns worsens the prognosis. About half of the patients have sleep breathing disorders with variable proportions of central and obstructive apneas. Obstructive apneas are acutely deleterious to ventricular function. On the long run, they may be responsible for a worsening of the disease due to the permanent sympathetic activation seen in obstructive sleep apnea. It is therefore important to detect sleep apnea in patients and to apply a treatment. The best therapeutic procedure in obstructive events appears to be CPAP, provided hemodynamic status is closely monitored.

A use of a neural network to evaluate contrast enhancement curves in breast magnetic resonance images

For the diagnosis of breast cancer using magnetic resonance imaging (MRI), one of the most important parameters is the analysis of contrast enhancement. A three-dimensional MR sequence is applied before and five times after bolus injection of paramagnetic contrast medium (Gd-DTPA). The dynamics of absorption are described by a time/intensity enhancement curve, which reports the mean intensity of the MR signal in a small region of interest (ROI) for about 8 minutes after contrast injection. The aim of our study was to use an artificial neural network to automatically classify the enhancement curves as "benign" or "malignant." We used a classic feed-forward back-propagation neural network, with three layers: five input nodes, two hidden nodes, and one output node. The network has been trained with 26 pathologic curves (10 invasive carcinoma [K], two carcinoma-in-situ [DCIS], and 14 benign lesion [B]). The trained network has been tested with 58 curves (36 K, one DCIS, 21 B). The network was able to correctly identify the test curves with a sensitivity of 76% and a specificity of 90%. For comparison, the same set of curves was analyzed separately by two radiologists (a breast MR expert and a resident radiologist). The first correctly interpreted the curves with a sensitivity of 76% and a specificity of 90%, while the second scored 59% for sensitivity and 90% for specificity. These results demonstrate that a trained neural network recognizes the pathologic curves at least as well as an expert radiologist. This algorithm can help the radiologist attain rapid and affordable screening of a large number of ROIs. A complete automatic computer-aided diagnosis support system should find a number of potentially interesting ROIs and automatically analyze the enhancement curves for each ROI by neural networks, reporting to the radiologist only the potentially pathologic ROIs for a more accurate, manual, repeated evaluation.

Optimization of a novel bioerodible device based on auto-catalyzed poly(ortho esters) for controlled delivery of tetracycline to periodontal pocket

Local delivery of antimicrobial agents in inflamed periodontal pocket has been shown to be effective in reducing periodontopathic microorganisms. This research focuses on developing and characterizing bioerodible formulations based on auto-catalyzed poly(ortho esters) (POExLAy) for modulated release of tetracycline over 2 weeks. POExLAy are a new versatile family of POE-containing lactoyl lactyl dimers in the polymer backbone. By modifying the proportion of lactic acid in the polymer, viscous or solid materials having different degradation rate can be produced. The formulations can be either injected or placed as a solid device directly into the periodontal pocket. Tetracycline-free base incorporated into these materials was released within 10-14 days depending on polymer structure. Increase in lactic acid content in the polymer tended to increase the drug release rate and to reduce the initial lag time. Tetracycline release from such bioerodible delivery system occurs predominantly by surface erosion of the polymeric matrix, leading to kinetics which can be zero order. This periodontal drug delivery system is designed to be used as an adjunct in the treatment of periodontal diseases. Clinical studies are currently in progress.

Altered baroreflex gain during voluntary breathing in chronic heart failure

BACKGROUND

We assessed the behavior of the baroreflex (BR) gain in chronic heart failure (CHF) patients using the spectral analysis method during application of a forcing stimulus, i.e. respiration.

METHODS

Simultaneous RR interval and arterial pressure fluctuation recordings were obtained during two random-order periods of voluntary paced-breathing (0.15 Hz and 0.25 Hz) in seven patients with moderate CHF (NYHA class II/III; EF, 30+/-9%; peak VO(2), 18+/-5 ml kg(-1) min(-1)) and six age-matched controls. BR gain was assessed in the time (sequential method) and frequency (cross-spectral gain in the low and high frequency) domains.

RESULTS

Slower breathing was associated with a BR gain decrease in CHF patients whereas a BR gain increase was evidenced in controls (BR gain: 6+/-5 ms mmHg(-1) at 0.25 Hz vs. 4+/-3 ms mmHg(-1) at 0.15 Hz, P<0.05 in CHF; BR gain: 12+/-7 ms mmHg(-1) at 0.25 Hz vs. 15+/-7 ms mmHg(-1) at 0.15 Hz, P<0.05 in controls).

CONCLUSIONS

Voluntary breathing, which involves cortical centers in the brain, had major effects on cardiovascular system controller gain in CHF patients, indicating an impairment of the central neural regulation of the autonomic outflow.

Relationship between pulse interval and respiratory sinus arrhythmia: a time- and frequency-domain analysis of the effects of atropine

Respiratory sinus arrhythmia (RSA) estimation is commonly used as a non-invasive index of cardiac vagal tone. To test this relationship, vagal tone was augmented or blocked using atropine. The study was carried out using 14 healthy volunteers, following beta-adrenoceptor blockade (10 mg bisoprolol per os) and during controlled respiration (0.25 Hz) in order to limit the confounding effects of cardiac sympathetic tone and respiration pattern changes. Atropine was slowly infused intravenously over a 30-min period up to a vagolytic cumulative dose of 0.04 mg/kg. The instant vagal tone was compared to the instant RSA value obtained from a time-/frequency-domain analysis of pulse interval (PI). RSA and PI varied in the same direction with an initial increase corresponding to the early vagomimetic effect of atropine followed by a decrease during the vagolytic phase. The comparative percentage fluctuations of RSA and PI over this large vagal tone range indicate that RSA is more sensitive (about twofold) than PI in reflecting fluctuations around the set point. This dissociated behaviour of PI and heart rate variability could be important to our understanding of the circulatory changes that result from fluctuations in vagal inputs to the sinus node.

The effects of focus-skin distance and shaping block tray on the calibration factor of in-vivo dosimetry diodes

PURPOSE

In-vivo dose measurements during conformal treatment require correction factor evaluations for differences in block shapes, field size and source-skin distance (SSD). The aim of this paper is to evaluate a single correction factor, CFentranceSSD, depending only on source-skin distance, which takes into account both shape and size of blocked fields, in pelvic treatments.

MATERIALS AND METHODS

A set of measurements was performed to investigate the effects of different block shapes and sizes, source-skin distances and collimator settings on the entrance dose values. For this reason EDP 20 Scanditronix diodes, with 20 mm water-equivalent build-up cap, were irradiated by 2 Varian linear accelerators (Clinac 1800 and Clinac 2100) 18 MV photon beams with 3 different collimator settings. Diodes were calibrated by comparison with a Farmer 2571 ionization chamber at reference conditions (10 cm x 10 cm open field, source-skin distance 100 cm, build-up depth 3.3 cm) in order to convert the semiconductor signal into water absorbed dose. Three sets of different measurements (regarding open beams, tray fields and shaped fields) were performed. Diode responses were compared with the ionization chamber ones, in the same irradiation conditions.

RESULTS

The CFentranceSSD trends can be described by linear fits in dependence upon source-skin distance, and the effect with tray alone or with tray and blocks is stronger than in the open field. The observed effects can be interpreted by the influences of a) the different source distances of diode and reference point in the phantom and b) the secondary electron contamination of the photon beam upon the calibration factor of the diode.

CONCLUSION

The effects of source-skin distance and of the shaping blocks and tray upon the diode calibration factor can be effectively accounted for by a single CFentranceSSD correction factor.

Monitoring mobility in the early steps of unfolding: the case of oxidized cytochrome b(5) in the presence of 2 M guanidinium chloride

A Model-Free analysis of the (15)N relaxation properties of oxidized cytochrome b(5), a heme-containing electron-transfer protein, has been performed in 2 M guanidinium chloride (GdmCl), i.e., just before the heme is released by the action of denaturant. This analysis provides information on the mobility in the nano- to picosecond time range. A parallel study on the motions in the milli- to microsecond time scale has also been performed by analyzing rotating-frame (15)N relaxation rates. The protein contains a 60:40 ratio of two conformers (A and B) differing for the rotation of the heme group around the alpha-gamma meso axis. The effect of denaturant has been followed for both species, and the mobility properties have been compared with the analogous information in the absence of denaturant. To complete the picture, we also performed (15)N relaxation measurements and the Model-Free analysis of the native B form, whereas data on the A form [Dangi, B., Sarma, S., Yan, C., Banville, D. L., Guiles, R. D. (1998) J. Phys. Chem. B 102, 8201-8208], as well as rotating-frame measurements for both native forms [Banci, L., Bertini, I., Cavazza, C., Felli, I. C., Koulougliotis, D. (1998) Biochemistry 37, 12320-12330; Arnesano, F., Banci, L., Bertini, I., Felli, I. C., Koulougliotis, D. (1999) Eur. J. Biochem. 260, 347-354], are already available in the literature. It is found that GdmCl tends to increase the internal mobility, although some residues are rigidified on both time scales. In the milli- to microsecond time scale, the tendency to increased mobility is reflected in a decrease in the tau(ex) values rather than in the number of residues experiencing conformational equilibria. In the nano- to picosecond time scale, the tendency to increased mobility is indicated by an overall decrease in the S(2) values. Color pictures are reported to visually show these effects. On the fast time scale, the B form is more mobile than the A form, reflecting the different stability with respect to unfolding. The increase in mobility upon addition of denaturant largely occurs around the heme pocket, which facilitates the release of the heme. The relevance of the internal motions with respect to the early steps of the unfolding process is also analyzed and discussed.

Radiological findings when very small lung volumes are irradiated in breast and chest wall treatment

Acute pneumonitis following breast irradiation is a rare and transient phenomenon that can be easily managed by drugs. The aim of this study is to evaluate late sequelae on lung, after postoperative radiotherapy (RT) for breast cancer. We were concerned with investigating late radiological findings when very small lung volumes are involved in the irradiated volume. We studied 28 consecutive patients. They underwent clinical examination and all staging procedures before surgery, evaluation of pulmonary function with spirometry, postoperative chest x-ray and high resolution computed tomography (HRCT) of the lung before RT. Clinical examinations were usually performed every 3 months after RT. A second chest x-ray, HRCT and spirometry were carried out after nearly 7 months from the end of RT. We estimated the irradiated lung volume by measuring the area of the lung surface enclosed by the 50% isodose (LA50) in each profile. We found a significant correlation between LA50 and the score of radiological findings after RT. No correlations were found between other factors (i.e., adjuvant chemotherapy, age, weight, smoking) and lung fibrosis. No woman developed radiation pneumonitis syndrome or respiratory symptoms. Our results indicate that irradiation of the breast and/or chest wall is well tolerated if treatment planning is done accurately. The fibrosis likelihood is strongly correlated to the irradiated lung volume. The use of tangential fields limits radiological changes that can be detected only by HRCT examination and are not associated with clinical symptoms.