COS-Speech: protocol to develop a core outcome set for dysarthria after stroke for use in clinical practice and research.

BACKGROUND: Dysarthria after stroke is when speech intelligibility is impaired, and this occurs in half of all stroke survivors. Dysarthria often leads to social isolation, poor psychological well-being and can prevent return to work and social lives. Currently, a variety of outcome measures are used in clinical research and practice when monitoring recovery for people who have dysarthria. When research studies use different measures, it is impossible to compare results from trials and delays our understanding of effective clinical treatments. The aim of this study is to develop a core outcome set (COS) to agree what aspects of speech recovery should be measured for dysarthria after stroke (COS-Speech) in research and clinical practice. METHODS: The COS-Speech study will include five steps: (1) development of a long list of possible outcome domains of speech that should be measured to guide the survey; (2) recruitment to the COS-Speech study of three key stakeholder groups in the UK and Australia: stroke survivors, communication researchers and speech and language therapists/pathologists; (3) two rounds of the Delphi survey process; (4) a consensus meeting to agree the speech outcomes to be measured and a follow-up consensus meeting to match existing instruments/measures (from parallel systematic review) to the agreed COS-Speech; (5) dissemination of COS-Speech. DISCUSSION: There is currently no COS for dysarthria after stroke for research trials or clinical practice. The findings from this research study will be a minimum COS, for use in all dysarthria research studies and clinical practice looking at post-stroke recovery of speech. These findings will be widely disseminated using professional and patient networks, research and clinical forums as well as using a variety of academic papers, videos, accessible writing such as blogs and links on social media. TRIAL REGISTRATION: COS-Speech is registered with the Core Outcome Measures in Effectiveness Trials (COMET) database, October 2021 https://www.comet-initiative.org/Studies/Details/1959 . In addition, "A systematic review of the psychometric properties and clinical utility of instruments measuring dysarthria after stroke" will inform the consensus meeting to match measures to COS-Speech. The protocol for the systematic reviews registered with the International Prospective Register of Systematic Reviews. PROSPERO registration number: CRD42022302998 .

Field efficacy trial of a novel HVT-IBD vector vaccine for 1-day-old broilers.

Two vaccination programmes for infectious bursal disease (IBD) were compared in broiler chickens with maternal immunity, placed on two farms. A turkey herpes virus (HVT)-IBD vector vaccine was administered by the subcutaneous route, at the hatchery, into the chicks of farm A at the age of 1 day. On farm B, an attenuated intermediate live IBD vaccine was given orally at the ages of 17 and 24 days. The vaccine uptake was monitored via serology and bursa/body weight ratio evolution, as well as PCR-based viral IBDV detection in the bursa of Fabricius at various time points. It was also verified by an experimental very virulent IBDV challenge performed at the age of 30 days in birds transferred from the farms with appropriate control groups in a laboratory. An immunity gap was observed in birds from farm B between the decay of the passive and the rise of the active immunity based upon serological data. The level of protection against challenge is not possible to establish in this farm as the reduction of the bursa/body weight ratio observed could be due to the residual pathogenicity of the vaccine strain or the challenge as well. This immunity gap was not present on farm A showing higher serological titres at the ages of 26 and 45 days via a suitable ELISA test and 93% protection against the very virulent challenge at the age of 30 days was observed. The maternal immunity interfering with the live IBDV vaccine replication had no detectable effect on the vector vaccine take.

Expression of thymidine kinase driven by an endothelial-specific promoter inhibits tumor growth of Lewis lung carcinoma cells in transgenic mice.

The possibility of inhibiting tumor growth by limiting angiogenesis has raised considerable interest. In this study, we examined the feasibility of inhibiting tumor growth by targeting a suicide gene in the endothelium. Toxicity must be directed solely to angiogenic cells. Therefore, we used the herpes simplex virus-thymidine kinase (TK) gene, in combination with the prodrug ganciclovir (GCV), which affects replicative cells. To test this strategy, we produced transgenic mice carrying the TK gene driven by the vascular endothelial (VE)-cadherin promoter. Lewis lung carcinoma cells were injected subcutaneously to establish tumors and to test the effect of GCV on tumor growth. In two independent transgenic lines, GCV treatment (75 mg/kg/day) resulted in a 66-71% reduction of tumor volume at day 20 postimplantation compared to wild-type mice (650 and 550 versus 1930 mm(3), P<0.02 and 0.01, respectively), whereas no significant difference was observed when vehicle alone was injected. Tumor growth inhibition was accompanied by a marked reduction in tumor vascular density (151 versus 276 vessels/mm(2), P<0.05) and an increase in tumor cell death, suggesting that tumor growth inhibition was caused by a reduction in tumor angiogenesis. Our data support the potential utility of endothelial targeting of suicide genes in cancer therapy.

Intracochlear acoustic pressure measurements: transfer functions of the middle ear and cochlear mechanics.

Direct intracochlear acoustic pressure recordings (from 20 to 20,000 Hz) are used to measure the middle-ear transfer functions (forward and reverse) and to better understand the cochlear mechanics in the guinea pig. In the forward direction, the middle-ear transfer function is strongly dependent on the frequency and presents a maximum of +30 dB at 1,000 Hz (bulla open). In the reverse direction, the middle-ear transfer function looks like an ideal reverse middle-ear pressure transformer with -35 dB gain and 0 degrees phase lag from 20 to 8,000 Hz (bulla open, closed ear canal). Passive cochlear mechanics is studied with the help of intracochlear pressure measurements and differential cochlear microphonic potential recordings in the different turns.

Hearing Protection in the Military Environment.

The present state of passive (linear and non-linear) and active techniques for hearing protection in the military environment is reviewed. Solutions which allow to protect the ear from large continuous and high-level impulse noises while preserving the operational abilities of the personnel (detection, localisation, communication.) are emphasised.

Treatment of acoustic trauma.

The aim of this study is to determine the actual efficiency of the present medical treatments of acoustic trauma. Untreated and treated groups of guinea pigs are exposed to a traumatic noise exposure, inducing up to 60-dB threshold shift. The recovery is followed for up to 14 days. The first results indicate that in some animals the recovery of the threshold shifts are complete despite the fact that significant areas of hair cells are damaged. The most widely used medical treatments of acoustic trauma (oxygenotherapy, carbogen, hyperbaric oxygen, vasoactive agents, and corticotherapy) have been tested. Preliminary results indicate that pure oxygen and carbogen seem ineffective, hyperbaric oxygen used alone is dangerous, and corticoids and combined corticoid/hyperbaric oxygen seem to improve functional and morphological recovery. This study will be taken as a reference to look for new treatments that will be applied directly to the cochlea by means of an implanted osmotic micropump.

Role of connexin (gap junction) genes in cell growth control: approach with site-directed mutagenesis and dominant-negative effects.

Evidence is accumulating that connexin (Cx) genes form a family of tumor-suppressor genes. Our long-standing study revealed that, in almost all tumors, some abnormality in gap junction is observed, including loss or reduction of expression, aberrant localization of gap junction. In this study, we have examined the dominant-negative effects of mutant (prepared by site-directed mutagenesis) Cx43 constructs in C6 glioma cells, and of mutant Cx26 constructs in HeLa cells, on tumorigenicity. The mutant Cx43 A253V (Ala 253 to Val) inhibited the tumor-suppressive function exerted by wild-type Cx43 in C6 cells. Similarly, the mutant Cx26 P87L (Pro 87 to Leu) manifested dominant-negative inhibition of connexin-mediated cell growth control in HeLa cells. These results suggest that mutations of connexin genes can affect the tumor-suppressive function of gap junction and that gap junctional intercellular communication can be regulated by not only non-genotoxic but also genotoxic activities of environmental carcinogens.

Direct evidence of cubic difference tone propagation by intracochlear acoustic pressure measurements in the guinea-pig.

The fine tuning mechanisms involved in the normal processing of sound in the cochlea are non-linear, hence combination tones are generated inside the cochlea when a pair of low-level pure tones with neighbouring frequencies f1 and f2 is used as a stimulus. Their detection as sounds in the ear canal proves that they undergo backward propagation in the cochlea and through the middle ear, and the non-invasive measurement of the combination tone at 2f1-f2, called the cubic difference tone (CDT), has become a routine method of monitoring cochlear function. In order to gain information on the hypothetical places where CDTs are generated, on their intracochlear levels and propagation velocities, direct measurements of CDT pressure waves were carried out in scala vestibuli and tympani of the first and second turn of the guinea-pig cochlea. Cubic difference tones at 2f1-f2 varied from 0.75 to 9 kHz and were measured with a miniature piezoresistive transducer. Its high sensitivity allowed the detection of CDTs whenever their levels exceeded 5 dB SPL in the ear canal, i.e. 40 dB SPL (re: 20 microPa) inside the cochlea. The levels of CDTs were similar in scala vestibuli of the first and second turn. Phase comparisons between measurements at 2f1-f2 in the first and second turn allowed determination of the place where the CDT phase was minimum. It provided an estimation of the generation site of the CDT, which appeared to be close to the place tuned to f2 for stimulus levels lower than 70 dB SPL. Forward and backward travel times from one turn to the other were assessed at several frequencies, and both values were shorter than 0.2 ms. In contrast, the overall 'round-trip' delay of CDTs, measured in the ear canal, was about five times larger, suggesting that local filtering processes rather than propagation delays account for the overall CDT delay.

The specific problems of noise in military life.

In military life, noise has unusual characteristics and constitutes a serious hazard for hearing. Hearing impairments due to the exposure to weapon noises represent an important prejudice for the health of many soldiers. A special attention is given to (i) the "critical level", (ii) the frequency localization of the threshold shifts, (iii) the actual influence of the protective reflexes of the ear, (iv) the existence of delayed threshold shifts following impulse noise exposures, and (v) the interest of the medical treatment of the acoustic trauma. Damage risk criteria for weapon noises are compared: criteria using the (A-weighted) isoenergy principle represent the best present solution (LAeq = 85 dB). Specific problems related to the use of hearing protection are also discussed.

Long-term connexin-mediated bystander effect in highly tumorigenic human cells in vivo in herpes simplex virus thymidine kinase/ganciclovir gene therapy.

Gene therapy via the herpes simplex virus thymidine kinase (tk) gene and ganciclovir (GCV) treatment eliminates experimental tumors. In this approach, cells expressing the tk gene (tk+) and neighboring tumor cells which do not express the gene are killed. We have demonstrated this bystander effect is enhanced in vitro by gap junctional intercellular communication (GJIC). In order to extend our in vitro results into in vivo situations, we injected into nude mice different ratios of tk+/tk- HeLa cells, either lacking or transfected with connexin43 (Cx43), a gene coding for a gap junction protein. When GCV was administered before tumors were palpable, fewer animals developed tumors, even after a longer period, if the injected cells were mixtures of Cx43(+)-tk+ and Cx43(+)-tk- while tumor growth was not prevented with mixtures of HeLa cells not expressing Cx43, i.e. Cx43(+)-tk+/Cx43(-)-tk-. When GCV was given after the appearance of tumors, the size of the tumors from Cx43- cells was 30% reduced for 3 weeks if 50% of the injected cells were tk+. However, for cells expressing Cx43, the tumor size was 66% reduced if 10% of the cells were tk+. Such a reduction demonstrates a long-term bystander effect which is dependent on Cx43 expression.

Dominant-negative abrogation of connexin-mediated cell growth control by mutant connexin genes.

Connexin genes exert negative growth control when transfected into various types of tumor cell lines. We previously demonstrated that connexin 26 (Cx26) suppresses in vitro and in vivo growth of HeLa cells. In this study, we have examined whether certain Cx26 mutants can abrogate cell growth control and the gap junctional intercellular communication (GJIC) capacity of such Cx26-transfected HeLa cells. For this purpose, we transfected three mutated Cx26 genes (C60F, P87L and R143W) into HeLa cells already containing the wild-type Cx26 gene, which are GJIC-competent and non-tumorigenic. Transfection of P87L and R143W mutants enhanced the tumorigenicity of the HeLa Cx26 cells in nude mice without any change in GJIC capacity. On the other hand, transfection of the C60F mutant reduced the GJIC capacity of HeLa Cx26 cells without affecting their growth in vivo. Immunostaining studies demonstrated that the Cx26 proteins were localized mainly at cell-cell contact areas in the HeLa Cx26 cells both before and after transfection of mutated Cx26 genes. These results suggest that certain mutant Cx26 proteins exert a dominant-negative effect on Cx26-regulated growth of HeLa cells and that such effects may be independent of the effect on GJIC ability. It is proposed that wild-type and mutant Cx26 proteins produce heteromeric connexons and that such heteromeric connexons may exert different effects on growth control from those of homomeric connexons.

Reverse middle-ear transfer function in the guinea pig measured with cubic difference tones.

Otoacoustic emissions are increasingly useful for determining cochlear function noninvasively. It is widely agreed that these acoustic signals reflect micromechanical processes in the cochlea. However, their quantitative interpretation requires knowledge of the ways in which vibrations travelling back to the ear canal from the cochlea are shaped by the middle ear. An intracochlear source is needed to derive the reverse middle-ear transfer function (rMETF) by comparing pressure in the external ear canal to the corresponding pressure in scala vestibuli. In the present study, the rMETF was obtained in vivo in the guinea pig using as intracochlear sound source the cubic difference tones (CDTs) generated by a pair of external pure tones. With a closed ear canal and open bulla, the rMETF was found to be flat (-35 dB) over a broad frequency range (1.5-8 kHz). The differences between forward and reverse METF could be explained by different loads acting on the middle ear network, which depends on the direction of signal transmission. With knowledge of the rMETF, it becomes possible to quantify CDTs within the cochlea by measuring them noninvasively in the ear canal.

Partial regression, yet incomplete eradication of mammary tumors in transgenic mice by retrovirally mediated HSVtk transfer 'in vivo'.

Mice transgenic for the activated rat neu oncogene under the control of the mouse mammary tumor virus long terminal repeat (MMTV-LTR) (neu+ mice), develop breast tumors in 100% of cases. We have previously reported that double transgenic mice obtained from crossing neu+ mice with mice transgenic for the herpes simplex virus thymidine kinase (HSVtk) gene can be used as a suitable model to test the 'suicide gene' strategy for mammary tumor gene therapy in vivo. In the present study, we evaluated the efficacy of the HSVtk/ganciclovir (GCV) system in the neu+ mice by inoculating cells producing a retroviral vector bearing the HSVtk gene in the mammary tumors on one side of the animals, and comparing their weight with that of the contralateral tumors, after systemic GCV administration. A statistically significant effect of this therapy was clearly seen (P < 0.001) but complete eradication of the tumors could not be achieved. This was not due to the inefficient delivery of GCV, as no HSVtk expression was detected in the residual tumors, but could be related to the low transduction efficiency (< 10%) and to inability of the 'bystander effect' (probably due to the absence of functional gap-junctions among mammary tumor cells) to kill nontransduced neoplastic cells. These data suggest that results obtained by in vivo models using transplanted tumor cell lines as targets for gene therapy might not be immediately transferable to spontaneously arising tumors in animals or humans.

[Biomechanics of the middle ear]. / Biomécanique de l'oreille moyenne.

We describe the main biomechanical characteristics of the middle ear in man and in animals. Physical principles of functionment, tympano-ossicular displacements, acoustic reflex, adaptation of impedance, transfer function of the middle ear, middle ear as an acoustic power transformer... are presented. Practical consequences for the hearing sensitivity, the susceptibility to noise and some clinical applications are discussed.

[Effect of noise on the auditory transduction]. / Effets du bruit sur la transduction sensorielle.

The effects of noise on the auditory transduction and the temporary and permanent threshold shifts (TTS and PTS) are reviewed in relation to the physiology, the morphology and the mechanics of the Corti's organ and especially of the outer hair cells. The modification of the mechanical characteristics of the stereocilia: decrease of stiffness, shortening of the rootlets, softening of the interciliary links...reduce the number of ionic channels which are opened during the mechanical excitation of the Corti's organ. This reduction modifies greatly the behavior of the "cochlear amplifier" which is located at the level of the outer hair cells and is responsible for the auditory sensitivity at threshold and the frequency selectivity. Permanent damages to the stereocilia of the hair cells following exposure to noise seem to be the main factor responsible for the apparition and the extent of the hearing losses. The influence cof several parameters: amplitude, duration, frequency..., on TTS and PTS are reviewed and the phenomenon of the half-octave shift is described.

Effectiveness of earplugs in high-intensity impulse noise.

The efficiency of different types of earplugs was assessed by means of Békésy audiometry following the exposure of 42 human subjects to weapon impulses. The peak pressure of the impulses ranged from 2.3-27.8 kPa (from 161 to 183-dB peak SPL) and the A-weighted equivalent level (over 8 h) of each exposure ranged from 100-114 dB. All subjects wore earplugs fitted by an experienced individual. The devices tested included one brand of conventional foam earplugs and a number of different models of perforated earplugs, one type of which had been previously shown to provide nonlinear attenuation. Perforated earplugs were tested because they provide better speech communication than conventional passive earplugs, and in the nonlinear case also afford attenuation that increases with the peak pressure of the impulses. The temporary threshold shifts (TTSs) observed in these experiments were very small and indicated no significant hazard for hearing. Well-fitted perforated earplugs seem to be able to protect the ear from infrequent exposures to the high-level impulses produced by small and large weapons while allowing good speech communication, and without impairing the operational capacity of soldiers who must remain aware of their acoustic environment.

Experimental look at cochlear mechanics.

The mechanisms by which the organ of Corti is stimulated by acoustic stimuli are discussed on the basis of experimental observations. This discussion refers to the resonance theory as well as to the traveling wave (TW) theory. The measurement of the basilar membrane displacements, of the cochlear microphonic (CM) responses to pure tones and impulses, and the recording of the intracochlear acoustic pressure seem to indicate that, at least in the basal part of the cochlea and for frequencies up to the characteristic frequency of a given location, the cochlear responses do not exhibit large phase lags and long delays which characterize the one-dimensional long-wave models (in which a TW transports the energy along the cochlear partition). These experimental observations suggest that the cochlear partition is excited simultaneously as a whole, more or less like a bank of resonators, as proposed a long time ago by Helmholtz.

Delayed temporary threshold shift induced by impulse noises (weapon noises) in men.

Most of the available information on the effects of impulse noise on hearing is derived from temporary threshold shift (TTS2) measurements performed 2 min after a single exposure to small-weapon noises. TTS is known to recover as a linear function of the logarithm of time when it is induced by a continuous noise of moderate intensity. Following the exposure to impulse noise, several investigators have reported individual exceptions to the log-time relation, e.g. increases in TTS during the first hour of recovery. These authors observed a 'rebound recovery function' for most of the exposed men, and they conclude that this phenomenon '... has implications for the use of TTS in the construction of damage risk criteria for hazardous noise exposure ..., a single measure, such as the widely used TTS2 may not be an adequate index of the magnitude of the TTS'. In order to thoroughly investigate in man the existence of 'delayed' TTS following the exposure to actual weapon noises, the 'French Committee on Weapon Noises' carried out the following study. Three groups of soldiers (28 subjects) wearing no hearing protection were exposed in the free field over 2 days to impulse noises produced by a rifle. Békésy audiograms were obtained from each subject just before the exposure, and at 5 min, 1 h and 4 h after exposure. All audiometric tests were carried out even when no TTS was observable in the first postexposure audiogram. A significant number of subjects showed a 'delayed TTS' and/or 'rebound recovery'. The maximum TTS was observed at 1 h after exposure, but the observation of a delayed recovery and a rebound recovery indicate that audiometric tests should be performed in all cases at least up to 4 h after the exposure. More detailed work is necessary to establish what changes may be necessary in the present damage risk criteria for impulse noises of a very high level.