Assessing the visual vertical: how many trials are required?

BACKGROUND: The visual vertical (VV) consists of repeated adjustments of a luminous rod to the earth vertical. How many trials are required to reach consistency in this measure? This question has never been addressed despite the widespread clinical use of the measurement in stroke rehabilitation. METHODS: VV perception was assessed (10 trials) in 117 patients undergoing rehabilitation after a first hemisphere stroke. The intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated for each patient category: with contralesional VV bias (n = 48), ipsilesional VV bias (n = 17) and normal VV (n = 52). RESULTS: For patients with VV biases, 6 trials were required to reach high inter-trial reliability (contralesional: ICC = 0.9, SEM = 1.36°; ipsilesional: ICC = 0.896, SEM = 0.96°). For patients with normal VV, a minimum of 10 trials was required (ICC = .728, SEM = 1.13°). A set of 6 trials correctly classified 96 % of patients. CONCLUSIONS: In the literature, 10 is the most frequently used number of trials used to assess VV orientation. Our study shows that 10 trials are required to adequately measure VV orientation in non-selected subacute stroke patients. For complex protocols imposing a decrease in the number of trials in each condition, 6 trials are needed to identify VV biases in most patients.

Measuring verticality perception after stroke: why and how?

About 80 papers dealing with verticality after stroke have been published in the last 20years. Here we reviewed the reasons and findings that explain why measuring verticality perception after stroke is interesting. Research on verticality perception after stroke has contributed to improve the knowledge on brain mechanisms, which build up and update a sense of verticality. Preliminary research using modern techniques of brain imaging has shown that the posterior lateral thalamus and the parietal insular cortex are areas of interest for this internal model of verticality. How they interact and are critical remains to be investigated. From a clinical standpoint, it has now been clearly established that biases in verticality perception are frequent after a stroke, causing postural disorders. Measuring the postural vertical with the wheel paradigm has allowed elucidating the mechanisms of lateropulsion, leading or not to a pushing. Schematically, patients with a hemispheric stroke align their erect posture with an erroneous reference of verticality, tilted to the side opposite the lesion. In patients with a brainstem stroke lateropulsion is usually ipsilesional, and results rather from a pathological asymmetry of tone, through vestibulo-spinal mechanisms. These evolutions of concepts and measurement standards of verticality representation should guide the emergence of rehabilitation programs specifically dedicated to the sense of verticality after stroke. Indeed, several pilot studies using appropriate somatosensory stimulation suggest the possibility to recalibrate the internal model of verticality biased by the stroke, and to improve uprightness. Vestibular stimulations seem to be less relevant and efficient.

Risk genes in head and neck cancer: a systematic review and meta-analysis of last 5 years.

The aim of this work was to identify risk genes related to the development and progression of squamous cell carcinoma head and neck (SCCHN) and do a meta-analysis of available estimates. Eligible gene/polymorphism studies were identified by electronic searches. Individual participant data of 8540 patients with HNC and 9844 controls from 19 genetic studies were analyzed, yielding adjusted (tobacco, gender, age and alcohol) odds ratios (OR) and 95% confidence intervals (CIs) comparing cases with controls. A meta-analysis was done on the studies that applied fixed and random models. People have an increase of polymorphism expression related to inflammation (NFKB1-294-ATTG, TNFα308-A2A2/A2A1, and TNFß252- B2B2/B2B1) or carcinogenic metabolism (GSTM1 null, and CYP1A1 m1/m1), representative of malignancy development. Furthermore, the increased expression of genes associated with the stabilization and repair of the cellular (OGG1-Asp267Asn, Ser279Gly Ile253Phe, 1578A>T, 1582C>T Ala399Glu (1542C>A) 1582insG 1543_1544delCT), and genes associated with the regulation of proliferation, apoptosis or tumor survival (miRNA499-CT/CC, CRYABC802G-CG/GG) are considered as risk factors. In this scheme, only the polymorphisms of ADH7A92G-GG and DEC1606-T/C genes are protective against malignancy transformation. The TP53, GSTM1 and CYPA1genes have been evaluated in more than one study and analyzed for homogeneity in each genotype. The meta-analysis showed no significant association between different allelic variants of Arg72Pro rs1042522 and SCCHN risk. In a model of tumorigenesis, an increased risk of SCCHN is associated with DNA repair and DNA stabilization genes. In addition, the polymorphisms involved in inflammation and carcinogenic metabolism processes represent an increased risk of SCCHN.

[Is the sense of verticality vestibular?]. / Le sens de verticalité est-il vestibulaire ?

The vestibular system constitutes an inertial sensor, which detects linear (otoliths) and angular (semicircular canals) accelerations of the head in the three dimensions. The otoliths are specialized in the detection of linear accelerations and can be used by the brain as a "plumb line" coding earth gravity acceleration (direction). This property of otolithic system suggested that the sense of verticality is supported by the vestibular system. The preeminence of vestibular involvement in the sense of verticality stated in the 1900s was progressively supplanted by the notion of internal models of verticality. The internal models of verticality involve rules and properties of integration of vestibular graviception, somaesthesic graviception, and vision. The construction of a mental representation of verticality was mainly modeled as a bottom-up organization integrating visual, somatosensory and vestibular information without any cognitive modulations. Recent studies reported that the construction of internal models of verticality is not an automatic multi-sensory integration process but corresponds to more complex mechanisms including top-down influences such as awareness of body orientation or spatial representations.

Fractal dimension as an index of left ventricular ischaemia: a pilot study.

Myocardial perfusion is performed by the left and the right coronary arteries, which deliver blood to the left and right ventricles, respectively. The impairment of arterial flow supply to the cardiac muscle by disease denotes a phenomenon known as ischaemia. Previous studies have demonstrated the ability of fractal dimension (FD) value of a physiological parameter in differentiating healthy/pathological behaviours. The aim of this study consisted in quantifying the loss of ventricular thickness fractal complexity in order to determine if FD is an intrinsic marker of acute coronary ischaemia. Five mongrel dogs weighing 18.8-26.5 kg (24.4 ± 3.3, mean ± SD) were submitted to this studio. A left ventricular pressure transducer and a fluid-filled catheter for later calibration of the pressure transducer were introduced through a stab wound near the apex. Two pairs of ultrasonic microcrystals (5 MHz) for continuous wall thickness measurements were implanted at the anterior and posterior walls of the left ventricle following a previously described technique. During coronary occlusion, the ischemic wall started to thin at the very onset of relaxation (showing abnormal motility), while the normoperfused wall displayed postejective thickening. Concomitantly, posterior ventricular wall thickness and anterior wall ventricular thickness showed a significant decrease in its FD value (P <0.05). In conclusion, loss of time series fractal complexity (waveform fine structure diminution or 'unwrinkling') constitutes a marker of the presence of an ischemic process. As a result, a single scalar value is sufficient to characterize the entire behaviour of the time series. This value manifested a similar trend compared to the most well-known clinical indices of myocardial ischaemia.

A patient-specific method for the evaluation of wall shear stress in human coronary arteries.

Atherosclerotic plaques form at specific sites of the arterial tree, an observation that has led to the "geometric risk factor" hypothesis for atherogenesis. It is accepted that the location of atherosclerotic plaques is correlated with sites subjected to low abnormal values of wall shear stress (WSS), which is in turn determined by the specific geometry of the arterial segment. In particular, the left coronary artery (LCA) is one of the most important sites of plaque formation and its progression may lead to stroke. However, little is known about hemodynamics and WSS distributions in the LCA. The purpose of this work is to set up a method to evaluate flow patterns and WSS distributions in the human LCA based on real patient-specific geometries reconstructed from medical images.

Somaesthetic perception of the vertical in spinal cord injured patients: a clinical study.

PURPOSE: The perception of verticality results from the integration of vestibular, visual and somatosensory information. Spinal cord injured patients with complete paraplegia have total somatosensory deafferentation below a certain metameric segment. In our study, we were interested in the implication of somatosensory signal in the construction of verticality and in the possible effect of somatosensory loss on spatial representation. METHOD: We analysed haptic and postural aspects of perceived verticality in 14 spinal cord injured patients with complete paraplegia and in an age- and gender-matched group of 13 controls. We also conducted a structured interview on the existence of vertigo or postural instability in daily life. RESULTS: The spinal cord injured patients perceived verticality without any significant directional bias in the orientation of the vertical but with a greater uncertainty than control subjects, both in haptic and postural modalities. If paraplegic did not report vertigo, half described an altered spatial perception without vision. CONCLUSION: The present results confirm the importance of sensory input from the trunk and the lower limbs in the perception of the vertical. However, visual and vestibular information appear to compensate for somatosensory deafferentation.

Association between mechanics and structure in arteries and veins: theoretical approach to vascular graft confection.

Biomechanical and functional properties of tissue engineered vascular grafts must be similar to those observed in native vessels. This supposes a complete mechanical and structural characterization of the blood vessels. To this end, static and dynamic mechanical tests performed in the sheep thoracic and abdominal aorta and the cava vein were contrasted with histological quantification of their main constituents: elastin, collagen and muscle cells. Our results demonstrate that in order to obtain adequate engineered vascular grafts, the absolute amount of collagen fibers, the collagen/elastin ratio, the amount of muscle cells and the muscle cells/elastic fibers ratio are necessary to be determined in order to ensure adequate elastic modulus capable of resisting high stretches, an adequate elastic modulus at low and normal stretch values, the correct viscous energy dissipation, and a good dissipation factor and buffering function, respectively.

Asymmetric standing posture after stroke is related to a biased egocentric coordinate system.

BACKGROUND: Weakness and somatosensory deficits have long been known to be involved in the postural instability of subjects with stroke. Recently, it has been shown that impaired representations of the orientation of the longitudinal axis of the body (LBA, egocentric reference) and of verticality (allocentric reference) may also play a role. The objective of the present study was to determine whether these two references were independently linked to postural asymmetry in standing stroke patients. METHODS: Twenty-two subjects were tested after a first hemispheric stroke (13 +/- 7.5 weeks). The LBA perception was investigated in the supine position by adjusting the orientation of a luminous rod in the frontal plane to correspond to the subjective LBA. The subjective visual vertical (SVV) was assessed by adjusting the orientation of a luminous line in the frontal plane to correspond to the SVV in upright patients. Weight distribution was measured in the standing position for about 2 minutes and 45 seconds by two separate force platforms under the feet. RESULTS: LBA and SVV were strongly associated (r = 0.7; p < 0.001). The estimate of the LBA was a better predictor (r = -0.52: p < 0.02) of weight bearing asymmetry than was SVV (r = -0.41; p = 0.074) when adjusted for motor weakness and hypoesthesia. CONCLUSION: Contralesional rotation of the longitudinal axis of the body could lead to unequal distribution of loading on the feet. This novel interpretation of weight bearing asymmetry underlines the complexity of control of the erect stance following stroke and brings new perspectives for rehabilitation programs.

Arterial complex elastic modulus was preserved after an intercontinental cryoconserved exchange.

There is a pressing need to obtain adequate vascular substitutes for arterial by-pass or reconstruction. Since the performance of venous and commercially prosthetic grafts is not ideal and the availability of autologous arteries is limited, the use of cryopreserved arteries has emerged as a very attractive alternative. In this sense, the development of an inter-continental network for cryopreserved tissue exchange would improve international cooperation increasing the possibilities of obtaining the requested materials. In this work, the effects of an inter-continental shipment, which includes cryopreservation, on the biomechanical properties of sheep aortas were evaluated by means of the arterial complex elastic modulus. It is shown that these properties were preserved after the shipment. The actual possibilities of establishing a network for arterial exchange for the international cooperation are discussed.

Cryografts implantation in human circulation would ensure a physiological transition in the arterial wall energetics, damping and wave reflection.

Each artery conduces blood (conduit function, CF) and smoothes out the pulsatility (buffering function, BF), while keeping its wall protected against the high oscillations of the pulse waves (damping function, xi). These functions depend on each segment viscoelasticity and capability to store and dissipate energy. When a graft/prosthesis is implanted, the physiological gradual transition in the viscoelasticity and functionality of adjacent arterial segments is disrupted. It remains to be elucidated if the cryografts would allow keeping the physiological biomechanical transition. The aim of this study was to evaluate the cryografts capability to reproduce the functional, energetic and reflection properties of patients' arteries and fresh homografts. Common carotid's pressure, diameter and wall-thickness were recorded in vivo (15 patients) and in vitro (15 cryografts and 15 fresh homografts from donors). Calculus: elastic (Epd) and viscous (Vpd) indexes, CF, BF, dissipated (WD) and stored (WPS) energy and xi. The graft-patient's artery matching was evaluated using the reflection coefficient (Gamma) and reflected power (WGamma). Cryografts did not show differences in Epd, Vpd, BF, CF, WD, WPS, and xi, in respect to fresh homografts and patients' arteries, ensuring a reduced Gamma and WGamma. Cryografts could be considered as alternatives in arterial reconstructions since they ensure the gradual transition of patients' arteries biomechanical and functional behavior.

Perception of longitudinal body axis in patients with stroke: a pilot study.

BACKGROUND AND AIMS: To investigate the hypothesis that patients with a hemisphere stroke may perceive their longitudinal body axis (LBA) rotated in the frontal plane. This error in an egocentric frame of reference could be detrimental to posture, as tilted LBA would imply an unequal distribution of body mass about the true vertical. METHOD: 26 healthy subjects matched in age with 18 patients living with stroke participated in the study. The 18 patients were tested on average 80 days after a first left (n = 8) or right (n = 10) hemisphere stroke. Participants perceived their LBA by adjustments of the orientation of a luminous rod pivoting around a dorsonavel axis to the subjective direction of LBA. Participants were studied in the supine position to dissociate somaesthetic cues from graviceptive cues. RESULTS: Patients with stroke perceived their LBA rotated to the contralesional side in comparison with controls (p = 0.004). For all controls and 10 patients with stroke, the perceived LBA was very close to true LBA (mean (SD) 0.24 degrees (1.31 degrees)). For eight patients with stroke (six right stroke, two left stroke), the perceived LBA was rotated from true body orientation in the direction opposite to the lesioned side (range 3-9.5 degrees, mean 5.2 degrees). These eight patients provided similar estimates by tactile manipulation of the rod (without vision). The rotation of perceived LBA was more pronounced for right-hemisphere strokes. The magnitudes of perceptual rotations correlated with sensory loss, signs of spatial neglect and the degree of postural and gait disability. CONCLUSION: This is the first study showing that certain patients with a hemisphere stroke perceive their LBA rotated to the contralesional side. The consequences for perceptuomotor coordination have implications for their postural disorders.

Mutation in the Trapalpha/Ssr1 gene, encoding translocon-associated protein alpha, results in outflow tract morphogenetic defects.

Translocon-associated protein complex (TRAP) is thought to be required for efficient protein-specific translocation across the endoplasmic reticulum membrane. We created a mutation in the Trapalpha gene that leads to the synthesis of a truncated TRAPalpha protein fused to ShBle-beta-galactosidase. Analysis of Trapalpha cDNAs reveals that among three different messenger RNAs expressed in the mouse, one of them encodes a slightly larger protein that differs in its C-terminal end. This mRNA, specific for skeletal muscle and heart, is only expressed after birth. Homozygous Trapalpha mutant pups die at birth, likely as a result of severe cardiac defects. Indeed, the septation of the proximal part of the outflow tract is absent, resulting in a double-outlet right ventricle. Studies of protein secretion in transfected embryonic fibroblasts reveal that the TRAP complex does not function properly in homozygous mutant cells and confirm, in vivo, the involvement of TRAP in substrate-specific translocation. Our results provide the first in vivo demonstration that a member of the TRAP complex plays a crucial role in mammalian heart development and suggest that TRAPalpha could be involved in translocation of factors necessary for maturation of endocardial cushions.

Importancia de una terapia preventiva de caries durante el tratamiento ortodóncico / The importance of a caries preventive program during orthodontic treatment

El objetivo de este estudio es analizar los resultados de un programa preventivo de caries durante el tratamiento de pacientes con aparatos fijos ortodóncicos. Sesenta y siete pacientes en tratamiento ortodóncico fueron divididos en 4 grupos (GI, GII, GIII y GIV). GI, GII y GIII son pacientes con alto riesgo de caries y GIV son pacientes con bajo riesgo de caries. En GI se aplicó un programa preventivo de caries desde el comienzo del tratamiento ortodóncico, en GII sólo se aplicó el programa durante el tratamiento y en GIII y GIV no se aplicó programa alguno. Los 4 grupos fueron examinados cada 6 meses, donde se evaluó el índice de placa interproximal (IPI), índice de sangrado papilar (ISP), test de saliva, número de lesiones cariosas y se calculó el riesgo de caries. El programa preventivo se efectuó cada 3 meses e incluyó instrucción y motivación de higiene, air-polishing, limpieza interproximal, fluoruración tópica y barnices (clorhexidina). Los resultados mostraron en GI y GII una mejora significativa de ISP, IPI y disminución del riesgo de caries. GIII mantuvo el alto riesgo de caries y tanto ISP, IPI como la aparición de manchas blancas aumentaron significativamente. GIV presentó un claro y significativo aumento del riesgo de caries asociado a un deterioro de la higiene bucal. Estos resultados muestran que el riesgo de caries aumenta en todos los pacientes durante un tratamiento ortodóncico con aparatos fijos, por lo que se aconseja la aplicación de un programa profiláctico regular cada 3 meses en todos los pacientes, incluso en aquellos con bajo riesgo de caries

This study analyses the results of a caries preventive program carried out during the orthodontic treatment of patients with fixed appliances. 67 patients with fixed appliances in orthodontic treatment were divided in 4 groups (GI, GII, GIII and GIV).GI, GII and GIII patients are high caries risk and GIV patients are low caries risk. A preventive program was applied for GI at the beginning and during the orthodontic treatment, for GII it was only applied during the treatment and for GIII, GIV the program was not applied at all. The 4 groups were examined every 6 months and it was evaluated approximal plaque index, bleeding index., saliva test, appearance of lesions and white spots and the caries risk. The preventive program was applied every 3 months and included hygiene instruction and motivation, Air-Polishing, approximal cleaning, topical fluoridation and application of varnishes (chlorhexidine). The results showed that in GI and GII there was a significant improvement of approximal plaque index, bleeding index and decrease in caries risk. In GIII the high caries risk stayed, while plaque index, bleeding index as well as the appearance of white spots increased significantly. GIV presented a clear and significant increase of the caries risk associated with a worsening of the oral hygiene. These results show that the caries risk increases in all the patients during orthodontic treatment with fixed appliances and recommends the application of a regular prophylactic program every 3 months in all the patients included those with low caries risk

[A quality program in haemovigilance: evaluation of the blood transfusion chain]. / Démarche qualité en hémovigilance: analyse du processus transfusionnel.

Blood transfusion, like any effective therapy, involves an element of risk. In order to reduce such risks to a maximum, a legislative and statutory framework has been set up. A reliable evaluation of this system is necessary together with an efficient evaluation method whose aim is to guarantee quality service. Favouring the development of the evaluation of professional practices is one of the priorities of the National Agency of Accreditation and Evaluation in Health (ANAES) created in April 1996. Following the recommendations from ANAES, the University Hospital of Brest decided to set up an evaluation of blood transfusion chain from the prescription of blood products to the transfusion act and follow-up of receivers in two health care services. The method used for this evaluation was a clinical audit. It is a method of evaluation, which allows with the help of certain criteria, care practices to be compared to accepted references, in order to measure the quality of these practices and the results of hospital care, so that improvements may be added. We present here the method and results of this evaluation, as well as the improvements we have put in place.

Comparative effects of inhaled budesonide and the NO-donating budesonide derivative, NCX 1020, against leukocyte influx and airway hyperreactivity following lipopolysaccharide challenge.

Lipopolysaccharide (LPS) inhalation (30 microg ml(-1), 1 h) caused airway hypereactivity (AHR) to histamine (1 mM, 20 s) 1 h later in conscious guinea-pigs. Bronchoalveolar lavage fluid (BALF) levels of neutrophils, myeloperoxidase (MPO) and protein were elevated whereas nitric oxide (NO) metabolites were reduced 1 h after LPS compared with saline challenge. 24 h after LPS, there was no AHR, but BALF neutrophils, eosinophils, macrophages, MPO, protein and NO metabolites were all raised. Budesonide (0.7 mM) and a molar equivalent concentration of the NO-donating budesonide derivative, NCX 1020, were inhaled (15 min) at 24 h and 45 min before LPS. The only change produced by budesonide was to reduce eosinophil influx at 24 h after LPS, compared with vehicle treated animals. NCX 1020, however, blocked AHR and reduced neutrophils (1 and 24 h) and MPO (1 and 24 h), while NO levels were raised at 1 and reduced at 24 h after LPS. The combined inhalation before LPS of the NO donor, SNAP (1.4 mM), with budesonide (0.7 mM) blocked the AHR to histamine and significantly reduced neutrophils (1 and 24 h) and MPO (1 and 24 h), while NO levels were raised at 1 h after LPS. Thus, NO and a corticosteroid co-administered as NCX 1020 or budesonide with a NO donor, have an additive effect against LPS-induced inflammatory responses and may have value in the treatment of neutrophil-driven airways disease such as COPD.

Diferencias regionales en la biomecánica y amortiguamiento arterial sistémico y pulmonar / Regional differences in the biomechanical and systemic and pulmonary arterial buffer

Systemic arteries show higher vascular disease than pulmonary ones. The aim of this study was to establish regional and functional differences in the mechanical properties of arteries in both circulations. Pressure (Konigsberg) and diameter (Sonomicrometry) were measured in seven artery segments corresponding to each sheep (N=7) using a previously developed mock circulation loop...

[Evaluation of postoperative mortality and quality of life of patients over 75 years of age after valve replacement for aortic stenosis. Report of 110 cases]. / Evaluation de la mortalité et de la qualité de vie postopératoire des sujets de plus de 75 ans après remplacement valvulaire pour rétrécissement aortique. A propos de 110 cas.

The authors carried out a retrospective study of short and long-term mortality after aortic valve replacement and assessed the quality of life by the IRIS scale in patients over 75 years of age operated for severe aortic stenosis at the University Hospital of Brest between June 1990 and March 1995. The hospital files of 110 consecutive patients (71 women, 39 men; average age 78 +/- 2 years, range 75-85 years) were studied. The pre- per- and postoperative data was studied. Each survivor was contacted by telephone during the year 2000 and a health and IRIS quality of life questionnaire was sent to them. Precise information about patients who had died was obtained from the family and/or medical practitioner. In the preoperative period, 30.9% of patients had left ventricular failure. The average aortic valve surface area was 0.53 +/- 0.12 cm2. Of the patients who underwent coronary angiography (60%), one third had significant coronary lesions. Coronary artery bypass surgery was associated with aortic valve replacement in 10% of cases. Biological prostheses were used in 108 patients. The operative mortality was 8.2%. One year, 5 year and 10 year survival rates were 89.9%, 75.5% and 33.3% respectively. Of the survivors, 16.7% were in institutional care and 83.3% lived at home. A total of 77.8% were readmitted to hospital, about half of them for cardiac problems. Cardiac treatment was prescribed for 97% of patients. The quality of life questionnaire was completed by 35 patients: the quality of life was better than average in nearly 83% of these patients. Aortic valve replacement for aortic stenosis in patients over 75 years of age improves life expectancy which is almost the same as that of the normal population of the same age, and improves the quality of life by restoring functional autonomy, enabling the majority of them to live in their own houses most of the time.