[Outcome of adult patients with cystic fibrosis admitted to intensive care with respiratory failure: the role of non-invasive ventilation]

Recourse to mechanical ventilation may prove necessary in adult patients with cystic fibrosis who have reached the stage of severe respiratory insufficiency. We report the experience of an intensive care service using non-invasive ventilation (NIV) as the first step in the management of acute respiratory failure in these patients. The records of 16 patients with cystic fibrosis presenting with acute respiratory failure and treated with NIV were analysed retrospectively. The characteristics of the group were: mean age 26.9 +/- 9.5 years; mean FEV1 21.5 +/- 10.4% predicted; mean body mass index 16.8 +/- 2.1; mean Pa CO(2) on admission 66 +/- 15 mm Hg. The mean duration of NIV in the ICU was 10 +/- 7 days. Eight patients (50%) died after having been intubated on account of failure of NIV. The eight survivors were discharged home with long-term NIV (mean duration 235 +/- 158 days). Six of them have received a lung transplant. The mode of onset of respiratory failure was an important prognostic factor: a rapid onset (<7 days) was invariably associated with death, on the other hand a gradual deterioration (> 7 days) was noted in the eight patients able to leave the ICU. In conclusion NIV may be regarded as the treatment of choice in patients with cystic fibrosis admitted to ICU with respiratory failure. In the case of persistent hypercapnia after the acute episode long-term NIV may keep them stable while awaiting lung transplantation.

atonal is required for exoskeletal joint formation in the Drosophila auditory system

Hearing relies on the delicate arrangement of mechanoreceptor neurones and an acoustomechanical interface. The concerted action of these neural and non-neural components is essential to audition, raising the question of whether they also develop in a concerted way. Drosophila hears with its antennae. A specialized antennal joint allows the distal part of the antenna to vibrate in response to sound and, thus, to serve as the sound receiver. This receiver's vibration is transduced by a chordotonal sense organ (CHO) that is closely associated with the joint. Here, we report that atonal (ato), the proneural gene for CHOs, is required for the formation of this antennal joint. Biophysical measurements in hemi- and homozygous ato(1) mutant flies show that, in addition to eliminating the auditory CHO, loss of ato function makes the antennal receiver insensitive to sound, impairing its auditory function. Anatomically, the cause for this mechanical effect resides in the deprivation of mobile exoskeletal joint structures. Hence, ato, the homologue of mouse Math1, is required for the formation of both the auditory CHO and joint, providing a genetic link between the very neural and exoskeletal components that together transform fly antennae into ears.

[Treatment of obstructive sleep apnea syndrome with mandibular advancement appliances]

Mandibular advancement device provide a therapeutic option for obstructive sleep apnea syndrome (OSAS). Clinical improvement has been proven in the different available studies, mainly on nocturnal respiratory events and quality of sleep. Less snoring have been noted by bed partners and objective studies have demonstrated a decrease in snoring frequency and intensity. The effects of these appliances on upper airways resistance syndrome is not yet well documented. The significant clinical improvement is secondary to the decrease in the occurrence of apneas and hypopneas. Polysomnographic improvement criteria with an apnea hypopnea index less than 10 per hour has been noted in certain cases, although no improvement or even worsening was noted in other cases. Sleep architecture has also changed in these patients, with a decrease in the time spent in stages 1 and 2, and an increase in the time spent in stages 3, 4 and rapid eye movement sleep. Micro-arousals are also reduced in number. Somnolence and loss of attention are improved; these have been evaluated subjectively or by a well known and approved somnolence scale. In some cases a test for vigilance was done. Our results are identical to those published in the different studies concerning respiratory events and sleep architecture.

Evaluation of ventilators used during transport of ICU patients -- a bench study

OBJECTIVES

To evaluate portable ventilators.

DESIGN AND SETTINGS

Bench study.

MATERIALS AND METHODS

Five portable ventilators used for transporting ICU patients [Osiris 1, (ventilator a), Osiris 2, (ventilator b), Oxylog 1000, (ventilator c), Oxylog 2000, (ventilator d), AXR1a, (ventilator e)] and three ICU ventilators which can be used for this purpose [Horus, (ventilator f), T-Bird, (ventilator g), and SV 300, (ventilator h)] were compared using a test lung regarding: 1) their capability to maintain set tidal volumes (V(T)) of 300 ml, 500 ml, and 800 ml under a normal condition A [resistance (R) 5 cmH(2)O/l/s and compliance (C) 100 ml/cmH(2)0] and two abnormal conditions B (R 20-C 30) and C (R 50-C 100); 2) trapped volume (expired V(T)relative to inspired V(T)at 0.7 s, 1 s, and 1.4 s), an estimate of the expiratory resistance of both circuit and valve; and 3) the triggering system assessed from the measurements of Delta t, Delta P for two inspiratory efforts at a PEEP of 0 cmH(2)0 and 5 cmH(2)0 in ventilators b, d, f, g, and h. Flow and airway pressure were measured with an independent physiologic recording system.

RESULTS

1) V(T). For ventilators a-h, the mean+/-SD changes of a set V(T)of 300 ml were -2.6+/-0.2%, -9.7+/-0.2%, 0+/-0%, -6.1+/-0.2%, 1.0+/-0.3%, -2.1+/-1.7%, 0.3+/-0%, and -1.3+/-0.1% ( P<0.001), respectively, during condition B relative to A. Similar results were obtained for a V(T)of 500 ml and 800 ml and during condition C relative to A; 2) Trapped volume. For ventilators a-h, trapped volume averaged 1+/-1%, 20+/-0%, 30+/-0.4%, 20+/-1%, 1+/-0%, 19+/-0%, 15+/-0%, and 14+/-0% at 0.7 s ( P <0.001) and 0.6+/-0%, 5+/-0%, 0.5+/-0%, 0+/-0%%, 0+/-0%, 0.6+/-0%, 0+/-0%, and 0+/-0% at 1.4 s ( P=NS); and 3) the triggering system of Oxylog 2000 was poor whereas it was of good quality for Horus, T-Bird, SV 300, and Osiris 2.

CONCLUSIONS

The small portable ventilators presently investigated varied between each other and were less accurate than ICU ventilators.

Acoustic sensitivity of fly antennae

The vast majority of higher flies - the brachycerans - is endowed with strikingly similar antennal morphologies and elaborate antennal mechanosensory organs. Thus far, however, the function of audition has been attributed only to the antennae of Drosophilid and Tephritid flies. Antennal mechanical sensitivity to sound is now documented in a broad range of fly species. These results highlight the wide occurrence of audition in as many as 120,000 species of higher Diptera. Antenna-based audition, as defined by the capacity of sensing the mechanical vibrations of the antenna in response to sound, thus appears to constitute an ubiquitous sensory capacity among higher flies. Functionally, antennal hearing can be used in the contexts of intraspecific acoustic signalling, flight control, and putatively close-range echolocation.

Comprehensive study on the chemical structure of dioxane lignin from plantation Eucalyptus globulus wood

Results of a comprehensive study on the chemical structure of lignin from plantation Eucalyptus globulus Labill are presented. Lignin has been isolated by a modified mild acidolysis method and thoroughly characterized by functional group analysis, by a series of degradation techniques (nitrobenzene oxidation, permanganate oxidation, thioacidolysis, and Py-GC-MS), and (1)H and (13)C NMR spectroscopy. Plantation Eucalyptus globulus lignin was found to be of the S/G type with an extremely high proportion of syringyl (S) units (82-86%) and a minor proportion of p-hydrophenyl propane (H) units (roughly 2-3 mol %). Unknown C-6 substituted and 4-O-5' type syringyl substructures represent about 65% of lignin "condensed" structures. Eucalypt lignin showed high abundance of beta-O-4 (0.56/C(6)) structures and units linked by alpha-O-4 bonds (0.23/C(6)). The proportion of phenylcoumaran structures was relatively low (0.03/C(6)). Different kinds of beta-beta substructures (pino-/syringaresinol and isotaxiresinol types) in a total amount of 0.13/C(6) were detected. ESI-MS analysis revealed a wide molecular weight distribution of lignin with the center of gravity of mass distribution around 2500 u.

3D light scanning macrography

The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences.

Outcome of patients with idiopathic pulmonary fibrosis admitted to the ICU for respiratory failure

STUDY OBJECTIVES

To analyze the outcome of acute respiratory failure (ARF) in patients with idiopathic pulmonary fibrosis (IPF), and to evaluate the benefits of invasive and noninvasive mechanical ventilation (MV).

DESIGN

Retrospective study.

SETTING

University hospital.

PATIENTS

Fifteen consecutive patients with IPF referred to the ICU for ARF between January 1989 and June 1998.

MEASUREMENTS AND RESULTS

Fifteen patients (mean +/- SD age, 64 +/- 10 years) were included. Eight patients had clinical, functional, and radiologic features of IPF, and the remaining seven patients also had biopsy specimen-proven IPF. The mean duration between diagnosis of IPF and admission to the ICU was 26.5 +/- 28 months. At the time of ICU admission, mean arterial blood gas levels were as follows: PaO(2)/fraction of inspired oxygen, 113 +/- 95; pH, 7.32 +/- 0.10; and PaCO(2), 55 +/- 21 mm Hg. All patients received MV; 12 patients required tracheal intubation, either at the time of ICU admission (n = 10) or after failure of noninvasive ventilation (NIV; n = 2); and 3 patients only received NIV. Three of the five patients receiving NIV died of respiratory failure. Eleven patients died in the ICU, either from hypoxemia (n = 8) or from septic shock (n = 3). Four patients were discharged alive from the ICU, and two of them died shortly thereafter.

CONCLUSION

The outcome of patients with IPF referred to the ICU for ARF was very poor and not improved by MV. Without a clearly identified reversible cause of ARF, these patients should not benefit from admission to the ICU.

Innovative biomechanics for directional hearing in small flies

In humans and animals alike, the localization of sound constitutes a fundamental processing task of the auditory system. Directional hearing relies on acoustic cues such as the interaural amplitude and time differences and also, sometimes, the signal spectral composition. In small animals, such as insects, the auditory receptors are forcibly set close together, a design constraint imposing very short interaural distances. Due to the physics of sound propagation, the close proximity of the sound receivers results in vanishingly small amplitude and time cues. Yet, because of their directionality, small auditory systems embed original and innovative solutions that can be of inspirational value to some acute problems of technological miniaturization. Such ears are found in a parasitoid fly that acoustically locates its singing cricket host. Anatomically rather unconventional, the fly's auditory system is endowed with a directional sensitivity that is based on the mechanical coupling between its two hemilateral tympanal membranes. The functional principle permitting this directionality may be of particular relevance for technological applications necessitating sensors that are low cost, low weight, and low energy. Based on silicon-etching technology, early prototypes of sub-millimeter acoustic sensors provide evidence for directional mechanical responses. Further developments hold the promise of applications in hearing aid technology, vibration sensors, and miniature video-acoustic surveillance systems.

A shot in the dark: the silent quest of a free-flying phonotactic fly

To reproduce, females of the parasitoid fly Ormia ochracea detect and localise a calling male cricket upon which they deposit their endoparasitic larvae. Calling male crickets are therefore subject to both sexual and natural selection by simultaneously attracting mates and phonotactic parasitoids. The possible strategy of song interruption employed by the cricket host to reduce his attractiveness to acoustic parasitoids was tested in the laboratory by examining the fly's phonotactic quest in response to synthetic cricket songs. Phonotactic flight trajectories were recorded in three dimensions with a stereo infrared video tracking system while the sound stimulus was controlled on-line as a function of the fly's position in space. Within a single flight, three distinct phases could be observed: a take-off phase, a cruising phase, during which course and altitude were rather constant, and a landing phase characterised by a spiralling descent towards the sound source. The flies showed remarkable phonotactic accuracy in darkness; they landed at a mean distance of 8.2 cm from the centre of the loudspeaker after a flight distance of approximately 4 m. The present data illustrate the fly's surprising ability to gauge the direction and distance of a sound source in three dimensions and, subsequently, to find it in darkness and silence.

Active auditory mechanics in mosquitoes

In humans and other vertebrates, hearing is improved by active contractile properties of hair cells. Comparable active auditory mechanics is now demonstrated in insects. In mosquitoes, Johnston's organ transduces sound-induced vibrations of the antennal flagellum. A non-muscular 'motor' activity enhances the sensitivity and tuning of the flagellar mechanical response in physiologically intact animals. This motor is capable of driving the flagellum autonomously, amplifying sound-induced vibrations at specific frequencies and intensities. Motor-related electrical activity of Johnston's organ strongly suggests that mosquito hearing is improved by mechanoreceptor motility.

Structure-toxicity relationships of polycyclic aromatic hydrocarbons using molecular quantum similarity

The establishment of quantitative structure-activity relationship (QSAR) models for the toxicity of polycylic aromatic hydrocarbons (PAHs) is described. Two properties, in vitro percutaneous absorption in rat skin and discrete levels of carcinogenic activity, are examined using molecular quantum similarity measures (MQSM). The results show that MQSM produces comparable, or even better, results than other approaches using physicochemical, topological and quantum-chemical molecular descriptors. Furthermore, a careful analysis puts into evidence that most of the information characterized by the original descriptors is in fact contained in the molecular density functions, the basis of MQSM. The present paper, together with several other reported by our laboratory, proves that MQSM might be appropriate theoretical tools for QSAR and computer-aided drug design, comparable to other highly predictive QSAR methodologies.

[The pectoralis myofascial flap in oropharyngeal and pharyngolaryngeal reconstruction in salvage surgery]

BACKGROUND

The pectoralis major myofascial (PMMF) flap is rapidly mobilized, reliable in a number of clinical situations calling for vascularized soft tissue coverage in the head and neck. Salvage surgery after radiation failures produce salivary fistula, skin flap necrosis, vascular rupture. Use of PMMF improves healing in such cases.

METHODS

A retrospective review performed at the university hospital, Marseille, between August 1987 and August 1999, was undertaken in two groups of salvage surgery. Groupe 1: protection of great vessels and fistula prevention after total laryngectomy (TL) and pharyngolaryngectomy (PL). Groupe 2: intra oral and pharyngeal defects reconstruction. Outcomes were classified in three types: type 1 - no complications; type 2 - delayed healing; type 3 - complicated healing. In groupe 2, in six cases the amount of flap contraction was analysed by C.T. scan.

RESULTS

83 PMMF was performed. Groupe 1, 57 cases (TL 28 cases, PL 26 cases); groupe 2, oral cavity défect 9 cases; oropharyngeal défects; 17 cases. There was no flap necrosis or vascular rupture. The donor site complications rate was 9.2%. The overall complications follow up was; groupe 1; type 1: 66%; type 2: 32%; type 3: 2%. In the groupe 2, type 1: 81%; type 2: 19%; type 3: 0%. The flap contracture was 30%. The use of PMMF in salvage surgery must be indicated in all cases after TL or PL, and is an excellent alternative from soft tissue coverage of oropharyngeal defects.

Photometric observations of a polychromatic laser guide star

We report the photometric observation of a polychromatic laser guide star (PLGS) using the AVLIS laser at the Lawrence Livermore National Laboratory (LLNL). The process aims at providing a measurement of the tilt of the incoming wave front at a telescope induced by atmospheric turbulence. It relies on the two-photon coherent excitation of the 4D5/2 energy level of sodium atoms in the mesosphere. We used two laser beams at 589 and 569 nm, with a maximum total average output power of approximately 350 W. For the purpose of photometric calibration, a natural star was observed simultaneously through the same instrument as the PLGS at the focus of the LLNL 50-cm telescope. Photometric measurements of the 330-nm return flux confirm our previous theoretical studies that the PLGS process should allow us at a later stage to correct for the tilt at wavelengths as short as approximately 1 microm at good astronomical sites. They show also that, at saturation of two-photon coherent absorption in the mesosphere, the backscattered flux increases by a factor of approximately 2 when the pulse repetition rate decreases by a factor of 3 at constant average power. This unexpected behavior is briefly discussed.

The histological architecture of the auditory organs in the parasitoid fly Ormia ochracea

Gravid females of the parasitoid fly species Ormia ochracea (Diptera: Tachinidae) rely on their sense of hearing to detect and localize their hosts, field crickets of the genus Gryllus. As in any hearing insect species, the fly's auditory system consists of a rather complex cascade of mechanical and physiological mechanisms, starting with the conversion of the acoustic energy in the sound field into mechanical vibrations that, in turn, are sensed in the auditory sensory organs by multicellular mechanoreceptive units - the scolopidia. This article reports on the histological architecture of the sensory organs using conventional histological serial sections and their three-dimensional reconstructions, and confocal laser microscopy. The scolopidia's spatial distribution and the three-dimensional organization of the actin-containing attachment cells are described. Morphometric measurements show that individual scolopales vary in their size and shape. Pronounced intersexual differences have been previously shown to exist in auditory function, in particular with respect to frequency sensitivity, peripheral auditory anatomy, and notably behavior. The present results show that intersexual differences in the histoarchitecture of the sensory organs are small. Results are compared with some other insect auditory systems and are also discussed in terms of their significance for frequency sensitivity.

Hepatitis B exacerbation with a precore mutant virus following withdrawal of lamivudine in a human immunodeficiency virus-infected patient

Chronic active hepatitis B exacerbations have been reported following development of resistance to or withdrawal of lamivudine in HIV-infected patients. A 38-year-old woman with HIV and chronic HBV infections was hospitalized because of acute hepatitis. The occurrence of cytolysis with replication of HBV 2 months after withdrawing lamivudine suggests that our patient experienced a severe reactivation of HBV infection due to the modification of her treatment. Sequencing of the HBV precore region showed the strain to be a mutant. We conclude that lamivudine should not be stopped in HIV- and HBV-infected patients, but could be continued at the dose of 100mg/day as used in isolated HBV infection.

Tracking of flying insects using pan-tilt cameras

Potent and affordable video and computer systems for automatic data acquisition are becoming increasingly important in behavioural neuroscience. It has remained challenging, however, to acquire data from small and fast-moving animals, such as insects in flight, due to the limited spatial and temporal resolution of the systems currently available. Our research on free-flying insects motivated the development of new methods in the context of two different experimental settings. First, the position and precise body axis direction of honey bees approaching a food source were automatically measured. Second, the flight trajectories of a phonotactic parasitoid fly homing in on its cricket host were recorded in 3D. We used pan-tilt cameras, i.e. cameras with moveable optics, to follow the animal's path with a close up image. Novel methods were developed for image acquisition and position measurement using pan-tilt cameras, as well as calibration and data evaluation in 3D world coordinates. The innovations of this system comprise: (1) Acquisition of images in high spatial detail over large observation areas. (2) Image acquisition at a field rate of 50 Hz PAL. (3) Free positioning of the cameras for 3D acquisition. (4) Computation of the flight path in 3D world coordinates. We illustrate the capabilities of the system with data obtained from a calibration object as well as from the behaviour of unrestricted, free-flying flies and bees. Potential applications in behavioural neuroscience and the psychophysics of sensory perception are briefly discussed.