Prevalence and evaluation of oropharyngeal dysphagia in patients with severe acute respiratory syndrome coronavirus 2 infection in the intensive care unit.

OBJECTIVE: The main objective was to assess the prevalence of dysphagia in the intensive care unit in patients with coronavirus disease 2019.Methods. A cohort, observational, retrospective study was conducted of patients admitted to the intensive care unit for severe acute respiratory syndrome coronavirus 2 pneumonia at the University Hospital of Rouen in France. RESULTS: Over 4 months, 58 patients were intubated and ventilated, 43 of whom were evaluated. Screening revealed post-extubation dysphagia in 62.7 per cent of patients. In univariate analysis, a significant association was found between the presence of dysphagia and: the severity of the initial pathology, the duration of intubation, the duration of curare use, the degree of muscle weakness and the severity indicated on the initial scan. At the end of intensive care unit treatment, 22 per cent of the dysphagic patients had a normal diet, 56 per cent had an adapted diet and 22 per cent still received exclusive tube feeding. CONCLUSION: Post-extubation dysphagia is frequent and needs to be investigated.

A large panel of chicken cells are invaded in vivo by Salmonella Typhimurium even when depleted of all known invasion factors.

Poultry are the main source of human infection by Salmonella. As infected poultry are asymptomatic, identifying infected poultry farms is difficult, thus controlling animal infections is of primary importance. As cell tropism is known to govern disease, our aim was therefore to identify infected host-cell types in the organs of chicks known to be involved in Salmonella infection and investigate the role of the three known invasion factors in this process (T3SS-1, Rck and PagN). Chicks were inoculated with wild-type or isogenic fluorescent Salmonella Typhimurium mutants via the intracoelomic route. Our results show that liver, spleen, gall bladder and aortic vessels could be foci of infection, and that phagocytic and non-phagocytic cells, including immune, epithelial and endothelial cells, are invaded in vivo in each organ. Moreover, a mutant defective for the T3SS-1, Rck and PagN remained able to colonize organs like the wild-type strain and invaded non-phagocytic cells in each organ studied. As the infection of the gall bladder had not previously been described in chicks, invasion of gall bladder cells was confirmed by immunohistochemistry and infection was shown to last several weeks after inoculation. Altogether, for the first time these findings provide insights into cell tropism of Salmonella in relevant organs involved in Salmonella infection in chicks and also demonstrate that the known invasion factors are not required for entry into these cell types.

Protecting effect of PrP codons M142 and K222 in goats orally challenged with bovine spongiform encephalopathy prions.

Breeding towards genetic resistance to prion disease is effective in eliminating scrapie. In sheep, classical forms of scrapie have been eradicated almost completely in several countries by breeding programs using a prion protein (PrP) gene (PRNP) amino acid polymorphism. For goats, field and experimental studies have provided evidence for several amino acid polymorphisms that are associated with resistance to scrapie, but only limited data are available concerning the susceptibility of caprine PRNP genotypes to BSE. In this study, goat kids representing five PRNP genotypes based on three polymorphisms (M142, Q211 and K222 and the wild type I142, R211 and Q222) were orally challenged with bovine or goat BSE. Wild type goats were killed with clinical signs between 24-28 months post inoculation (mpi) to both challenges, and goats with genotype R/Q211 succumbed between 29-36 mpi. I/M142 goats developed clinical signs at 44-45 mpi and M/M142 goats remained healthy until euthanasia at 48 mpi. None of the Q/K222 goats showed definite clinical signs. Taken together the highest attack ratios were seen in wild type and R/Q211 goats, and the lowest in I/M142, M/M142 and Q/K222. In all genotype groups, one or more goats remained healthy within the incubation period in both challenges and without detectable PrP deposition in the tissues. Our data show that both the K222 and M142 polymorphisms lengthen the incubation period significantly compared to wild type animals, but only K222 was associated with a significant increase in resistance to BSE infection after oral exposure to both BSE sources.

Laccase wiring on free-standing electrospun carbon nanofibres using a mediator plug.

Electrospun carbon nanofibres (CNFs) containing CNTs were produced by electrospinning and subsequent thermal treatment. This material was evaluated as a bioelectrode for biofuel cell applications after covalent grafting of laccase. Bis-pyrene-modified ABTS was used as a plug to wire laccase to the nanofibres leading to a maximum current density of 100 µA cm(-2).

Picosecond acoustics in vegetal cells: non-invasive in vitro measurements at a sub-cell scale.

A 100 fs laser pulse passes through a single transparent cell and is absorbed at the surface of a metallic substrate. Picosecond acoustic waves are generated and propagate through the cell in contact with the metal. Interaction of the high frequency acoustic pulse with a probe laser light gives rise to Brillouin oscillations. The measurements are thus made with lasers for both the opto-acoustic generation and the acousto-optic detection, and acoustic frequencies as high as 11 GHz can be detected, as reported in this paper. The technique offers perspectives for single cell imaging. The in-plane resolution is limited by the pump and probe spot sizes, i.e. approximately 1 microm, and the in-depth resolution is provided by the acoustic frequencies, typically in the GHz range. The effect of the technique on cell safety is discussed. Experiments achieved in vegetal cells illustrate the reproducibility and sensitivity of the measurements. The acoustic responses of cell organelles are significantly different. The results support the potentialities of the hypersonic non-invasive technique in the fields of bio-engineering and medicine.

Diffraction of picosecond bulk longitudinal and shear waves in micron thick films. Application to their nondestructive evaluation.

In this paper, acute focusing of the laser pump beam ( approximately 0.5 microm) on the sample surface allows picosecond acoustic diffraction in thin metallic films. The resulting wavefronts propagate at a group velocity which differs from phase velocities in anisotropic films. Waveforms have been experimentally recorded in a gold layer (2.1 microm thick) for several distances between pump and probe on the sample surface. A specified signal processing based on a Synthetic Focalization Technique allows analyzing the space repartition of the acoustic wave vectors for both longitudinal and shear waves. Stiffness coefficients of the gold layer are then identified from wave arrival times.

Acoustic waves generated by a laser line pulse in a hollow cylinder.

A theoretical solution is proposed to predict acoustic waves generated in a homogeneous and isotropic hollow cylinder by a laser line source under either ablation or thermoelastic regime. The Fourier series expansion is introduced for one spatial coordinate to solve this transient response problem. Theoretical displacements are obtained in both regimes for aluminum hollow cylinders with various thickness including a rod of the same size. The corresponding displacements are observed experimentally by the laser ultrasonic technique. Agreement has been found in the time arrival, shape and relative amplitude of surface waves and various longitudinal and transverse bulk waves. These acoustic waves are further identified by the ray trajectory analysis. This work will be helpful when dealing with the inverse problem of the nondestructive evaluation of hollow cylindrical parts.

Identification of laser-generated ultrasounds in the response of the cylinder over time and space.

A theoretical solution is presented to identify laser-generated ultrasounds in the transient response over time and space of a cylinder impacted by a laser line pulse. Theoretical radial displacements at various observation angles are obtained for an aluminum cylinder under thermoelastic regime. The corresponding displacements are observed experimentally by the laser ultrasonic technique. Good agreement is found in the time arrival, shape and relative amplitude of surface waves and various longitudinal and transverse bulk waves. These laser-generated ultrasounds are further identified by the ray trajectory analysis. This work will be helpful for the inverse problem of the nondestructive evaluation of cylinder parts.

The transient response of a transversely isotropic cylinder under a laser point source impact.

The transient response of a transversely isotropic cylinder under a laser point source impact is solved theoretically. The radial displacement generated by the laser under the ablation regime is numerically calculated by introducing Fourier series expansion and two-dimensional Fourier transform. The validity of this theoretical solution is demonstrated on a fiber reinforced composite cylinder with a strong anisotropy. Experimental displacements are detected at the cylinder surface by the laser ultrasonic technique, and are analyzed by the ray trajectories. Corresponding theoretical displacements are calculated numerically and compared to the experimental signals. Good agreement is found. The diffraction effect caused by the cusp is observed in both theory and experiment.

Picosecond ultrasonics time resolved spectroscopy using a photonic crystal fiber.

We present a broadband picosecond ultrasonics time resolved spectroscopy. Detection of picosecond coherent acoustic phonons using a wavelength continuum generation in a photonic crystal fiber (PCF) with femtosecond laser pulses is developed. Measurements are performed for selected wavelengths of a broad wavelength probe pulse within a bandwidth of 250 nm with an 825 nm center wavelength on two samples made of tungsten and of gallium arsenide.

On the use of laser-ultrasonics technique to excite selectively cylinder acoustic resonances.

Acoustic propagation in the transverse plane of a cylinder is considered in this paper. The acoustic source is a line along the axis z of the cylinder coordinates, obtained by focusing the beam of a pulsed laser on the surface of the cylinder. Point detection is performed with a laser interferometer. By adequately combining elementary signals measured for a large number of relative source-receiver positions, a signal is synthesized containing the basic acoustic resonances of the cylinder. Various elementary signal combinations allow us to select the observed acoustic modes related to Whispering Gallery modes and to Rayleigh surface waves. The changes in the signal spectrum are discussed. These acoustic modes are experimentally selected and observed at ultrasonic frequencies for the first time.

Numerical analysis of bulk conical waves in anisotropic cylinders; application to stiffness tensor measurement.

A point source-point receiver technique, based on laser generation and laser detection of acoustic waves, allows determination of mechanical properties of an anisotropic cylinder. The nature of the material and the geometry of the sample give a dispersive behaviour to the diffracted waves and make the acoustic signature difficult to interpret. To overpass the intricacies, wave fronts (conical waves in the volume and helical waves on the surface) are synthesized from signals provided by scanning the primitive line of the cylinder with a laser point source. In order to distinguish between direct bulk conical waves and other contributions in the acoustic response, some considerations on line surface waves and on reflected bulk conical waves are supplied. The identification of the stiffness tensor components, based on the inversion of the bulk waves phase velocities, is applied to signals simulated for a composite material.

Acoustic waves generated by a laser point pulse in a transversely isotropic cylinder.

A three-dimensional (3D) model is presented to predict the acoustic waves generated by a laser point pulse in a transversely isotropic cylinder. The Fourier series expansion and the two-dimensional Fourier transform are introduced to calculate the 3D transient response under either the ablation or the thermoelastic generation. The presented physical model and the numerical inverse scheme are applied to a fiber reinforced composite cylinder with a strong anisotropy. Experimental radial displacements of the cylinder surface are detected by the laser ultrasonic technique and analyzed by the ray trajectories for both generation regimes. Corresponding theoretical displacements are obtained numerically and compared to the experimental signals. Good agreement is found between theoretical and experimental results. The focusing effects that anisotropy gives rise to are observed in both theory and experiment under either regime.

Identification of laser generated acoustic waves in the two-dimensional transient response of cylinders.

The published model [Appl. Phys. Lett. 82, 4379-4381 (2003)] for the two-dimensional transient wave propagation in a cylinder is modified to avoid the inherited integration of the numerical inverse scheme. The Fourier series expansion is introduced for one spatial coordinate to resolve the transient response problem: theoretical radial displacements in either the ablation or the thermoelastic regime are obtained with little numerical noise and short computation time. The normal mode expansion method fails to deliver results with the same accuracy. Acoustic waves are fully identified by the ray trajectory analysis. These identified waves are further verified on the experimental results observed with the laser ultrasonic technique.

Generation and detection of shear acoustic waves in metal submicrometric films with ultrashort laser pulses.

We present experimental and calculational results demonstrating the thermoelastic generation of shear acoustic waves using femtosecond laser pulses in submicrometric isotropic aluminum films. We show that the generation of the shear waves is correlated to the reduction of the width of the optoacoustic source on the surface. The presence of shear waves is related to acoustic diffraction and acoustic mode conversion at the thin film interfaces.

Bsm I polymorphism in the vitamin D receptor gene is related to bone collagen turnover in healthy infants.

We examined the vitamin D receptor genotypes (BB, Bb and bb) defined by the Bsml restriction endonuclease in relation to biochemical indices of bone metabolism in healthy Caucasian infants. We measured the serum concentrations of the carboxy-terminal propeptide of type I procollagen (PICP) and the urinary excretion of total pyridinoline, free, total and bound deoxypyridinoline, the type I collagen N-terminal and C-terminal cross-linked telopeptides. The concentrations of the urinary indices are expressed relative to creatinine. Subjects with BB genotype had the highest mean concentrations of free, total and bound deoxypyridinoline and of the N-terminal cross-linked telopeptide (PANOVA = 0.0016, 0.0004, 0.0002 and 0.0053, respectively). BB boys had a higher excretion of the C-terminal cross-linked telopeptide than the other genotypes (PANOVA = 0.0253). In a subgroup of homozygotes aged 10 (1) months, BB subjects had the highest levels of the C-terminal cross-linked telopeptide (p=0.03), and of total deoxypyridinoline (p=0.02) and pyridinoline (p=0.06) concentrations. No significant association between the vitamin D receptor genotype and PICP was found. These data suggest that there may be a contribution of the vitamin D receptor genotype to skeletal metabolism in early childhood.

Interactive effect of estradiol and vitamin D receptor gene polymorphisms as a possible determinant of growth in male and female infants.

An association between vitamin D receptor (VDR) gene polymorphism and body size has been observed in infants. We hypothesized that the estradiol receptor (ER) gene is another determinant of infant growth and that the effects of the VDR and ER genotypes may interact with each other. The ER genotype (PvuII and XbaI sites), VDR genotype (BsmI site), and body size during the first 2 yr of life were analyzed in 161 healthy Caucasian full-term babies homozygous for the BsmI polymorphism of the VDR gene (BB or bb). There was no significant association between ER polymorphism and 1) body weight in boys and girls, 2) body length in girls, or 3) body length in boys with a bb genotype. In contrast, ER polymorphism and body length were significantly associated in BB boys. Boys with the BBpp genotype were shorter at birth (P < 0.005) and at 10 months of age (P < 0.001) than boys with other genotypes. They were even shorter than girls with the same genotype. These results indicate some degree of interaction between the effects of the VDR and ER genes, leading to significant variations in body growth during infancy, especially in boys.

Association between vitamin D receptor gene polymorphism and sex-dependent growth during the first two years of life.

An association between vitamin D receptor (VDR) gene polymorphisms and bone mass variance has been observed in adult populations. To analyze possible association between VDR genotype and growth, we studied 589 healthy infants who were homogeneous for age, diet, and vitamin D status. The Bsm I, TaqI, and ApaI alleles' frequencies and genotypes were similar to those reported for Caucasian populations. Variations in Bsm I polymorphism were not associated with calcium intakes nor with serum levels of calcium, 25-hydroxyvitamin D, 1, 25-dihydroxyvitamin D, or alkaline phosphatase activity. But, they were associated with differences in body size. At 2 yr, homozygote BB (BsmI site absent) girls had higher length, weight and body surface area, and inversely, BB boys had lower weight, body mass index and body surface area, than their respective bb counterparts. As a result, gender-related differences were observed in Bb and bb, but not in BB populations. This VDR genotypic effect was observed also at birth and at 10 months in the longitudinal analysis of 145 selected full-term babies homozygous for the Bsm I polymorphism. These findings provide support for the hypothesis that VDR genotype influences intrauterine and early postnatal growth, directly or via interactions with gender-related growth regulators.

Procollagen propeptide and pyridinium cross-links as markers of type I collagen turnover: sex- and age-related changes in healthy children.

The correlations among age, gender, body size parameters, and type I collagen metabolism were evaluated in 183 healthy infants, aged 8.5-27.5 months. Collagen formation was assessed by measuring serum type I collagen carboxy-terminal propeptide, and degradation was determined by urinary pyridinoline and deoxypyridinoline (measured by high performance liquid chromatography) and cross-linked N- and C-terminal telopeptides of type I collagen (measured by NTx and CrossLaps assays). A new RIA specific for deoxypyridinoline was also evaluated. The results provide reference values at 10 months and 2 yr of age, including cross-linked C-terminal telopeptides (1492 +/- 685 and 1510 +/- 446 in boys; 1705 +/- 612 and 1849 +/- 611 micrograms/mmol creatinine in girls; mean +/- 1 SD). There was a good correlation between the high performance liquid chromatography and RIA data for deoxypyridinoline, showing that the RIA method is suitable for use in healthy children. Some correlations were found among peptide-bound cross-links, serum type I collagen carboxy-terminal propeptide, and the anthropometric parameters, suggesting that these peptides reflect bone resorption and also overall body type I collagen. Finally, there were age- and sex-related differences in the urinary excretion of the collagen degradation markers, suggesting that, unlike boys, girls maintain a high degree of collagen degradation up to the age of 24 months despite a decrease in their rate of collagen formation.

Individual patterns of food intake development in children: a 10 months to 8 years of age follow-up study of nutrition and growth.

Individual patterns of food intake development have been investigated on the basis of a longitudinal study of nutrition and growth carried out in 112 children at the ages of 10 months, and 2, 4, 6, and 8 years. On the average, energy intake increased steadily with age. However, individual subjects sometimes followed a different pattern. Approximately 1 out of 5 subjects decreased their intake between two examinations. Besides, less than half the children (43%) were in the same category of energy intake (defined as tertiles) at 10 months and 8 years of age. Similarly, 47% of the children were in the same weight/height (BMI) category at 10 months and 8 years. Correlations computed between early intakes (10 months, and 2, 4, and 6 years) and intakes at 8 years were better for energy and protein intake than for fat and carbohydrates (CHO), showing that intake of energy or protein early in life has a better predictive value of intake at later ages. Energy intake development has been examined in those children who were found to be lean, medium, and fat at the age of 8 years; it increased more between the ages of 4 and 6 years, in children who were fat at 8 years. Individual variations of anthropometric measurements during growth are well documented. The present study points out that similar individual variations of intake also exists. These variations could reflect regulatory processes acting during growth and should be taken into account in investigating the child's appetite.