Model-based signal processing enables bidirectional inferring between local field potential and spikes evoked by noxious stimulation.

BACKGROUND: Recording spontaneous and evoked activities by means of unitary extracellular recordings and local field potential (LFP) are key understanding the mechanisms of neural coding. The LFP is one of the most popular and easy methods to measure the activity of a population of neurons. LFP is also a composite signal known to be difficult to interpret and model. There is a growing need to highlight the relationship between spiking activity and LFP. Here, we hypothesized that LFP could be inferred from spikes under evoked noxious conditions. METHOD: Recording was performed from the medullary dorsal horn (MDH) in deeply anesthetized rats. We detail a process to highlight the C-fiber (nociceptive) evoked activity, by removing the A-fiber evoked activity using a model-based approach. Then, we applied the convolution kernel theory and optimization algorithms to infer the C-fiber LFP from the single cell spikes. Finally, we used a probability density function and an optimization algorithm to infer the spikes distribution from the LFP. RESULTS: We successfully extracted C-fiber LFP in all data recordings. We observed that C-fibers spikes preceded the C-fiber LFP and were rather correlated to the LFP derivative. Finally, we inferred LFP from spikes with excellent correlation coefficient (r = 0.9) and reverse generated the spikes distribution from LFP with good correlation coefficients (r = 0.7) on spikes number. CONCLUSION: We introduced the kernel convolution theory to successfully infer the LFP from spikes, and we demonstrated that we could generate the spikes distribution from the LFP.

Non cross-linked equine collagen (Salvecoll-E gel) for treatment of complex ano-rectal fistula.

BACKGROUND: Fistula-in-ano is one of the most commonly presenting anorectal diseases. Sphincter sparing treatment options should be considered in patients with complex fistulas. Salvecoll-E gel is a native collagen deantigenated and purified, non-cross-linked equine dermal extract, with an amino acid composition identical to human collagen. METHODS: The multicentric trial study was a prospective, single-arm observational clinical study with the objective to assess the efficacy of Salvecoll-E gel for anal fistula repair in 70 patients. All patients had undergone preliminary surgical treatment consisting of positioning of a draining loosing seton that was maintained for a period of 4-6 weeks. After seton removal, a gentle debridement and washing of the fistula track was performed. The scar tissue was removed from the internal orifice. Internal opening was covered by a side-to side mucosal suture. Salvecoll-E was injected through the external opening into the fistula track, the external opening it has been opened. RESULTS: Twelve months after surgery, 55 patients demonstrated a clinically healed fistula (78,5%), 15 patients have a recurrence (21,5%). Most of the recurrences were observed in the first 6 months of treatment (13/15, 86.6%). We don't observe any worsening in CCF score. The results obtained at 1 year certainly seem satisfactory and in line with the best results published in literature using mini-invasive techniques. CONCLUSION: Salvecoll-E gel is a promising non-invasive technique for conservative treatment of anal fistulas, it's well tolerated by the patients and, in case of recurrence, reinjection or all other known techniques are feasible.

Comparing multiple correspondence and principal component analyses with biomechanical signals. Example with turning the steering wheel.

The purpose of this article is to compare Principal Component Analysis (PCA) and a much less used method, i.e. MCA (Multiple Correspondence Analysis) with data being first changed into membership values to fuzzy space windows. For such a comparison, data from an experimental study about turning the steering wheel is used. In a didactic perspective, this article only considers one multidimensional signal with 5 components: 3 linked to the steering wheel angle and hand positions and 2 to hand effort variables. A discussion weighs out the pros and the cons of both methods with criteria such as the possibility to show complex relational phenomena, the analysis/computing time or the information loss inherent to the averaging stage (in the perspective to analyze several hundreds of large multidimensional signals).

The smartphone: a novel diagnostic tool in pollen allergy?

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Collection of normative data for spatial and temporal gait parameters in a sample of French children aged between 6 and 12.

OBJECTIVE: Normative data on gait is essential for clinical practice - especially in children whose gait pattern changes over time. Sets of normative gait data in healthy children vary significantly from one country to another. We decided to generate a specific reference database of gait parameters for French children. METHOD: Three hundred and eighty-two children (228 boys and 154 girls, aged between 6 and 12) were asked to walk as naturally as possible and at a self-selected speed on a GAITRite track. Velocity, step count, cadence, step time, step length, cycle time, stride length, base width, swing time, stance time, single support time and double support time were recorded. Parameters were analyzed by age group, height group and BMI. RESULTS: Velocity, step and stride length increased regularly with advancing age and height. Cadence decreased with height. All temporal parameters (except for double support) differed significantly (P<0.05) when comparing the 6-year-old group or the 7-year-old group with the 9-year-old group and older groups. A small number of temporal parameters (cadence, step time, cycle time and stance time) differed significantly when comparing 7-year-olds and 8-year-olds. Temporal parameters appeared rise in proportion height from 110 cm to 130 cm and then reached a plateau. Overweight was associated with a longer stance time and more double support. CONCLUSION: The gait pattern in French children aged between 6 and 12 differs from those recorded elsewhere in the world; although gait parameters appear to change in much the same way with age worldwide, our values (even when normalized) are different. Our local database should be of value in French studies of childhood gait disorders. Given that gait patterns do not appear to mature by the age of 12, it would be valuable to study gait patterns in a population of teenagers.

Involving patients who attempt suicide in suicide prevention: a focus groups study.

The aim of this study is to gain insight into the individual experiences of patients who attempt suicide in order to better understand the reasons for and emotions behind a suicide attempt, thus also gaining insight, through the patients' own input, into the risk and protective factors which might influence possible repeat attempts and the attitude towards the assistance they receive. Two focus groups were conducted involving 17 participants, all hospitalized at the time of research for attempting suicide. The patients proved themselves competent, even expert in indicating reasons for, risk factors of and prevention strategies for suicide. The main findings suggest that the relational factor represents a key point both as a trigger for the suicide attempt and for promoting the communication of the intent or for preventing a repeat suicide attempt, as interpersonal relationships and an empathic environment were, in essence, what was perceived as therapeutic and protective and enabled the expression of thoughts and self-understanding. Accordingly psychotherapy, non-specific relationship 'monitoring' after discharge and tutored self-help groups have been suggested. Feasibility and implementing methods as well as the role of the nurse for such interventions were discussed.

EOS orthopaedic imaging system to study patellofemoral kinematics: assessment of uncertainty.

BACKGROUND: Accurate knowledge of knee joint kinematics, especially patellofemoral joint kinematics,is essential for prosthetic evaluation so as to further improve total knee arthroplasty performances. Improving the evaluation of the functioning of the extensor apparatus appears,in this respect, particularly important in this optimization effort. OBJECTIVES: The aim of this study was to propose a new experimental setup for the analysis of knee joint kinematics and to validate its relevance in terms of accuracy and uncertainty.The technique developed herein combines 3D reconstruction imaging with the use of a motion capture system. MATERIAL AND METHODS: Eight pairs of fresh-frozen cadaver specimens with no evidence of previous knee surgery were studied using a new test rig where the femur remains fixed and the tibia is free to rotate. The flexion-extension cycles were executed using computer-controlled traction of the quadriceps tendon combined with an antagonist force applied to the distal part of the tibia. Knee joint kinematics were tracked using an optoelectronic motion capture system after a preliminary stage of data acquisition of bone geometry and markers position. This stage was carried out using a new digital stereophotogrammetric system, EOS, combined with specific 3D reconstruction software that also determined the coordinate system used in the kinematic analysis. The resulting uncertainty was assessed as was its impact on the estimated kinematics. RESULTS: Test results on eight knees validated the setup designed for the analysis of knee joint kinematics during the flexion-extension cycle. More specifically, the statistical results show that measurement uncertainty for rotations and translations remains below 0.4 and 1.8 mm,respectively, for the tibia and 0.4 and 1.2 mm for the patella (+/- 2 S.D. for all four measurements). DISCUSSION: The combination of 3D imaging and motion capture enables the proposed method to track the real-time motion of any bone segment during knee flexion-extension cycle. In particular,the new test rig introduced in this paper allows in vitro measurements of the patello femoral and tibiofemoral kinematics with a good level of accuracy. Moreover, this personalized experimental analysis can provide a more objective approach to the evaluation of knee implants as well as the validation of the finite-elements-based models of the patellofemoral joint.

Lifetime co-morbidity with different subtypes of eating disorders in 148 females with bipolar disorders.

OBJECTIVES: To evaluate the impact of Eating Disorders (EDs) lifetime co-morbidity among female with Bipolar Disorders (BDs) and to compare clinical and cognitive features among EDs subgroups. METHOD: A hundred and forty eight women with a lifetime history of Diagnostic and Statistical Manual, Fourth Edition (DSM-IV)-defined Bipolar-I, Bipolar-II and/or Cyclothymia, were consecutively enrolled to determinate the prevalence of co-morbid DSM-IV-defined Anorexia Nervosa [AN], Bulimia Nervosa [BN] or Binge Eating Disorder [BED]. Measures included the Structured Clinical Interview for the DSM-IV Axis I Disorders (SCID-I), the Clinical Global Impression (CGI) rating scale, the Eating Disorder Examination Questionnaire (EDE-Q) and BMI record. RESULTS: Forty six patients (31%) reported lifetime history of at least one ED: AN was the most common ED (n=23, 15.5%), followed by BED (n=21, 14.2%), and BN (n=8, 5.4%); 6 patients (4.1%) reported multiple lifetime EDs. As expected, BMI was highest in BED patients and lowest in those with AN. Clinical characteristics were similar in the 3 groups, while rapid cycling and co-morbid drug abuse were more common in BED compared to AN or No-ED group. As expected cognitive eating symptoms assessed by the EDE-Q were all more represented in AN than in No-ED patients. AN and BED only differed in restricting behavior and weight concerns. CONCLUSIONS: Our results prompt for the recognition of co-morbid EDs among bipolar patients, indicating that BED, along with other EDs, may influence in different ways both clinical characteristics and course of the illness. Further perspective studies are necessary to better define the relationships between different EDs and Bipolar Spectrum disorders.

Time-frequency analysis to detect bone fracture in impact biomechanics. Application to the thorax.

Experimental testing is a major source of data to quantify the tolerance of the human body to impact and to develop protection strategies. Correlating the time of rib fractures with the kinematics of the occupant and the action of safety systems would provide valuable data for assessing safety systems and developing injury risk functions. However, methods for determining rib fractures timing are not yet fully developed. Time-history analysis of data from multiple strain gauges mounted directly to ribs is commonly used for this purpose, but this method is not very sensitive and the time and cost required to instrument the rib cage with more than 100 strain gauges is prohibitive for many applications. In this study a new approach based on time-scale analysis of signals obtained from piezoelectric transducers (PZT) is reported. A post-mortem human subject was instrumented with four PZT on ribs 3 and 7 bilaterally and exposed to lateral blunt impacts to the shoulder and the chest. The fractures were documented after each test, and a criterion was developed to process the PZT signals. The criterion consists in detecting in the PZT signal the onset of a high frequency transient generated by the fracture of a rib using the continuous wavelet transform. Two thresholds were successfully determined to detect fractures that occurred (1) on an instrumented rib, and (2) on the adjacent rib. Further development of this method should allow the detection of all rib fractures using only a few PZT.

Long-term outcome of a multicentre randomized clinical trial of stapled haemorrhoidopexy versus Milligan-Morgan haemorrhoidectomy.

INTRODUCTION: Stapled haemorrhoidopexy is less painful than Milligan-Morgan haemorrhoidectomy, allowing an earlier return to working activities, but its long-term efficacy is not fully established. This study reports the long-term follow-up of a randomized clinical trial comparing the two techniques in 100 patients affected by third- and fourth-degree haemorrhoids. METHODS: All patients were contacted and invited to attend the clinic to assess long-term functional outcome. The degree of continence and satisfaction were assessed by questionnaire. Anal manometry and anoscopy were performed. RESULTS: Eighty patients were available after a median follow-up of 87 months. No statistically significant differences were found between the two groups in terms of incontinence, stenosis, pain, bleeding, residual skin tags or recurrent prolapse. A tendency towards a higher recurrence rate was reported in patients with fourth-degree haemorrhoids, irrespective of the technique used. No significant changes in anal manometric values were found after surgery in either group. CONCLUSION: Both techniques are effective in the long term.

[Cardiorespiratory fitness and arterial stiffness in sedentary and not sedentary hypertensive workers]. / Relazione tra VO2 e Augmentation Index in lavoratori sedentari e non, affetti da ipertensione arteriosa.

In hypertensive subjects, arterial stiffness and arterial wave early reflection are thought to be the major factor limiting cardiac reserve and exercise capacity. Aortic augmentation index (AIx) is a measure of arterial wave reflection and stiffness, and has been associated with decreased cardiorespiratory fitness. We investigated the role of physical activity at work and its effect on such association. 25 hypertensive middle-aged workers, without history of diabetes, cardiovascular disease, renal failure and inflammatory diseases, were studied. Our study confirms that AIx provides information for the prediction of VO2 peak, being also gained with a non-invasive and practical test. Inside the two groups of sedentary and non sedentary workers, the relation between AIx and VO2 peak is still significant; whereas the non sedentary group showed a worse cardiorespiratory fitness without significantly differences in arterial stiffness.

Hep27, a member of the short-chain dehydrogenase/reductase family, is an NADPH-dependent dicarbonyl reductase expressed in vascular endothelial tissue.

Human Hep27 was originally isolated from growth-arrested HepG2 cells and identified as a member of the superfamily of short-chain dehydrogenases/reductases (SDR). Its substrate specificity has not been determined, but a cross-species comparison suggests that it occurs in widely divergent species, such as human, Cenorhabditis elegans, Drosophila and Arabidopsis thaliana. In this study, Hep27 was expressed as a His(6) fusion protein, and subjected to a substrate screen, using a compound library of SDR substrates, comprising steroids, retinoids, sugars and carbonyl compounds. Whereas no steroid dehydrogenase or retinoid activity was detected, it was found that Hep27 catalyzed the NADPH-dependent reduction of dicarbonyl compounds, like 3,4-hexanedione and 1-phenyl-1,2-propanedione with similar turnover numbers as DCXR (a mitochondrial dicarbonyl reductase/xylulose reductase). In contrast, Hep27 does not convert sugar substrates like xylulose or threose. Based on its substrate specificity and expression in endothelial tissues, it is suggested that Hep27 functions as a dicarbonyl reductase in enzymatic inactivation of reactive carbonyls, involved in covalent modification of cellular components.

Identification of cells secreting a thymostimulin-like substance and examination of some histoenzymatic pathways in aging avian primary lymphatic organs: II. Bursa of Fabricius.

The Bursa of Fabricius of 15 day, 1-, 3-, and 6 month-old adult chickens (White Leghorn strain) were studied by histological and histochemical staining, histoenzymatic reactions (LDH, SDH, a-GPDH, NAD, NADPH, Ca++-dependent ATP-ase, pH 8.5) and by anti-thymostimulin immunoreaction. Positive reactions for mucopolysaccharides and enzymatic activities were located in the epithelia of the follicles, i.e. in follicle-associated-epithelium (FAE), inter-follicle-epithelium (IFE) and in different epithelial compartments of cortical and medullary zones. Positive reaction for thymostimulin-like (TS-like) substance was restricted to FAE cells and weakly to the basal lamina of IFE. In 6-month-old chickens, the FAE cells disappeared; the phenomenon of bursal regression was evident, although not all the follicles were involved. In the few still normal follicles, the good reactivity to the enzymes tested suggests that residual physiological activity is still present, even if reduced.

Lymphatic mapping and sentinel node identification in squamous cell carcinoma and melanoma of the head and neck.

AIM: The aim of our study was to evaluate the role of scintigraphy in lymphatic mapping and in the identification of the sentinel lymph node (SLN) in patients with head and neck cancer. METHODS: Between September 1999 and February 2001 we enrolled 22 consecutive patients with cancer in the head and neck region: five squamous cell carcinomas, one Merkel cell tumor of the cheek, and 16 malignant melanomas. Lymphoscintigraphy was performed three hours before surgery after injection of 30-50 MBq of 99mTc -Nanocoll in 0.3 mL; the dose was fractionated by injecting the radiotracer at two points around the lesion. Static acquisition (anterior and/or lateral views, 512 x 512 matrix, 5 mins pre-set time) was started immediately after the injections so as to visualize the pathways of lymphatic drainage. The skin projection of the SLN was marked with ink. Intraoperative SLN detection was performed with perilesional injection of patent blue. RESULTS: SLNs were found with lymphoscintigraphy in all patients. Thirty-three SLNs were identified: one occipital node, three nodes at the base of the tongue, 10 superficial lateral nodes (external jugular), five submandibular nodes, five submental nodes, three mastoid nodes and six supraclavicular nodes. Biopsy was performed in 21/22 patients. In 20/22 patients the first lymph nodes were visualized in the proximal cranial regions (retroauricular, jugular and submandibular) at five minutes post injection. The SLN positivity rate was 13.6% (three patients). All patients with tumor-positive SLNs were submitted to radical dissection. Poor concordance in the detection of sentinel nodes was observed with patent blue. CONCLUSIONS: The flow of nanocolloid in the lymph vessels of the head is rapid. In our experience immediate scintigraphic imaging was essential to visualize the pathways of lymphatic drainage and the first SLN. Radioguided SLN biopsy is therefore recommended within three hours. Injection of patent blue is inadvisable because of the poor concordance with lymphoscintigraphy and the risk of permanent tattooing of the face.