Opinion

The Editors of Letters in Applied Microbiology will, at their discretion, publish invited and submitted 'Opinions' on subjects in the general area of Applied Microbiology. They will not be subjected to the normal refereeing procedures and reprints will not be provided. The 'Opinions' will not necessarily represent the views of the Society for Applied Bacteriology or of the Editors. The Editors may invite or readers may submit 'Responses' to published 'Opinions' , provided that they are not merely polemics, and these will also be published at the discretion of the Editors. 'Responses' will be treated precisely like 'Opinions'. They should clearly indicate, in their first sentence, the 'Opinion' to which they are a response.     

Low Empathy in Deaf and Hard of Hearing (Pre)Adolescents Compared to Normal Hearing Controls

Objective

The purpose of this study was to examine the level of empathy in deaf and hard of hearing (pre)adolescents compared to normal hearing controls and to define the influence of language and various hearing loss characteristics on the development of empathy.

Methods

The study group (mean age 11.9 years) consisted of 122 deaf and hard of hearing children (52 children with cochlear implants and 70 children with conventional hearing aids) and 162 normal hearing children. The two groups were compared using self-reports, a parent-report and observation tasks to rate the children’s level of empathy, their attendance to others’ emotions, emotion recognition, and supportive behavior.

Results

Deaf and hard of hearing children reported lower levels of cognitive empathy and prosocial motivation than normal hearing children, regardless of their type of hearing device. The level of emotion recognition was equal in both groups. During observations, deaf and hard of hearing children showed more attention to the emotion evoking events but less supportive behavior compared to their normal hearing peers. Deaf and hard of hearing children attending mainstream education or using oral language show higher levels of cognitive empathy and prosocial motivation than deaf and hard of hearing children who use sign (supported) language or attend special education. However, they are still outperformed by normal hearing children.

Conclusions

Deaf and hard of hearing children, especially those in special education, show lower levels of empathy than normal hearing children, which can have consequences for initiating and maintaining relationships.     

Mechano-electrical Transduction: New Insights into Old Ideas

The gating-spring theory of hair cell mechanotransduction channel activation was first postulated over twenty years ago. The basic tenets of this hypothesis have been reaffirmed in hair cells from both auditory and vestibular systems and across species. In fact, the basic findings have been reproduced in every hair cell type tested. A great deal of information regarding the structural, mechanical, molecular and biophysical properties of the sensory hair bundle and the mechanotransducer channel has accumulated over the past twenty years. The goal of this review is to investigate new data, using the gating spring hypothesis as the framework for discussion. Mechanisms of channel gating are presented in reference to the need for a molecular gating spring or for tethering to the intra- or extracellular compartments. Dynamics of the sensory hair bundle and the presence of motor proteins are discussed in reference to passive contributions of the hair bundle to gating compliance. And finally, the molecular identity of the channel is discussed in reference to known intrinsic properties of the native transducer channel.     

Self-Esteem in Hearing-Impaired Children: The Influence of Communication,Education, and Audiological Characteristics

Objective

Sufficient self-esteem is extremely important for psychosocial functioning. It is hypothesized that hearing-impaired (HI) children have lower levels of self-esteem, because, among other things, they frequently experience lower language and communication skills. Therefore, the aim of this study was to compare HI children''s self-esteem across different domains with those of normal hearing (NH) children and to investigate the influence of communication, type of education, and audiological characteristics.

Methods

This large (N = 252) retrospective, multicenter study consisted of two age- and gender-matched groups: 123 HI children and 129 NH controls (mean age  = 11.8 years). Self-reports were used to measure self-esteem across four domains: perceived social acceptance by peers, perceived parental attention, perceived physical appearance, and global self-esteem.

Results

HI children experienced lower levels of self-esteem regarding peers and parents than NH controls. Particularly HI children who attended special education for the deaf were at risk, even after correcting for their language development and intelligence. Yet, levels of global self-esteem and self-esteem involving physical appearance in HI children equalled those of NH controls. Furthermore, younger age at implantation and longer duration of having cochlear implants (CIs) were related to higher levels of self-esteem.

Conclusion

HI children experience lower levels of self-esteem in the social domains. Yet, due to the heterogeneity of the HI population, there is high variability in levels of self-esteem.

Discussion

Clinicians must always be aware of the risk and protective factors related to self-esteem in order to help individual patients reach their full potential.     

Surveillance of human mitral valve cells by autochthonous lymphocytes,in vitro

Summary Analysis of a time-lapse film of cultured human mitral valve endothelium containing autochthonous lymphocytes reveals details of a pattern of interaction suggesting a previously undescribed type of cellular surveillance. Highly mobile lymphocytes rapidly approach individual endothelial cells, slowly circumnavigate the nuclear region, and rapidly move away to repeat this behavior on adjacent cells during the 1-month culture period. This work was supported by NRC of Canada Grant A-2351, a University of Victoria Faculty Research Grant and a summer studentship from the Victoria Medical Research Foundation.     

Hydrodynamic detection by cupulae in a lateral line canal: functional relations between physics and physiology

In the present review, signal-processing capabilities of the canal lateral line organ imposed by its peripheral architecture are quantified in terms of a limited set of measurable physical parameters. It is demonstrated that cupulae in the lateral line canal organ can only partly be described as canal fluid velocity detectors. Deviation from velocity detection may result from resonance, and can be characterized by the extent to which a single dimensionless resonance number, N _r , exceeds 1. This number depends on four physical parameters: it is proportional to cupular size, cupular sliding stiffness and canal fluid density, and inversely proportional to the square of fluid viscosity. Situated in a canal, a cupula may benefit from its resonance by compensating for the limited frequency range of water motion that is efficiently transferred into the lateral line canal. The peripheral transfer of hydrodynamic signals, via canal and cupula, leads to a nearly constant sensitivity to outside water acceleration in a bandwidth that ranges from d.c. to a cut-off frequency of up to several hundreds of Hertz, significantly exceeding the cut-off frequency of the lateral line canal. Threshold values of hydrodynamic detection by the canal lateral line organ are derived in terms of water displacement, water velocity, water acceleration and water pressure gradients and are shown to be close to the detection limits imposed by hair cell mechano-transduction in combination with the physical constraints of peripheral lateral line signal transfer. The notion that the combination of canal- and cupular hydrodynamics effectively provides the lateral line canal organ with a constant sensitivity to water acceleration at low frequencies so that it consequently functions as a low-pass detector of pressure gradients, supports the appropriateness of describing it as a sense organ that “feels at a distance” (Dijkgraaf in Biol Rev 38:51–105, 1963)     

A note on catalase enhanced recovery of acid injured cells of Gram negative bacteria and its consequences for the assessment of the lethality of L-lactic acid decontamination of raw meat surfaces

Addition of catalase (150 units/ml) to a rich infusion agar used for solid medium repair of acid injured pathogenic Enterobacteriaceae increased the recovery of such populations by 1–2 log cycles entailing an equal size reduction in the true lethality of this mode of processing for safety.