Staphylococcus Aureus Nasal Carriage, Exit-Site Infection and Catheter Loss in Patients Treated with Continuous Ambulatory Peritoneal Dialysis (CAPD)

Over a three-year period, 217 episodes of bacterial peritonitis occurred in 183 patient years. Thirty-seven episodes were due to Staphylococcus aureus and 19 (51 %) of these required removal of the catheter to eradicate infection. This compared with catheter loss in 4/63 (6.3%) coagulase negative staphylococci infections ( p < 0.001); 7/67 (9.5%) culture negative peritonitis ( p < 0.001); and 10/30 (33.3%) episodes due to gram-negative organisms ( p < 0.05). Over half (51.3%) the episodes due to S. aureus were associated with exit-site infections, and this rose to 100% (10/10) with recurrent peritonitis ( p < 0.01).

A prospective analysis of nasal carriage and exit-site infections due to S. aureus was carried out in 87 patients. Exit-site infections were present in 21 (24%), almost entirely due to different strains as judged by sensitivity patterns and phage typing. Nasal carriage, defined as two positive swabs within the study period, was present in 20 (23%) patients. Fourteen (70%) of these had exit site infections due to the same strain as that isolated from the nose, whereas no patient grew different strains from either site. Nasal carriage increased the risk of infection sixfold ( p < 0.001).

Astrocytes are important mediators of Aβ-induced neurotoxicity and tau phosphorylation in primary culture

Alzheimer's disease (AD) is pathologically characterised by the age-dependent deposition of β-amyloid (Aβ) in senile plaques, intraneuronal accumulation of tau as neurofibrillary tangles, synaptic dysfunction and neuronal death. Neuroinflammation, typified by the accumulation of activated microglia and reactive astrocytes, is believed to modulate the development and/or progression of AD. We have used primary rat neuronal, astrocytic and mixed cortical cultures to investigate the contribution of astrocyte-mediated inflammatory responses during Aβ-induced neuronal loss. We report that the presence of small numbers of astrocytes exacerbate Aβ-induced neuronal death, caspase-3 activation and the production of caspase-3-cleaved tau. Furthermore, we show that astrocytes are essential for the Aβ-induced tau phosphorylation observed in primary neurons. The release of soluble inflammatory factor(s) from astrocytes accompanies these events, and inhibition of astrocyte activation with the anti-inflammatory agent, minocycline, reduces astrocytic inflammatory responses and the associated neuronal loss. Aβ-induced increases in caspase-3 activation and the production of caspase-3-truncated tau species in neurons were reduced when the astrocytic response was attenuated with minocycline. Taken together, these results show that astrocytes are important mediators of the neurotoxic events downstream of elevated Aβ in models of AD, and suggest that mechanisms underlying pro-inflammatory cytokine release might be an important target for therapy.

Transgenic mouse models of tauopathy in drug discovery

Tauopathies, including Alzheimer's disease, are neurodegenerative diseases characterized by the deposition of hyperphosphorylated tau protein in the central nervous system, and are the major cause of dementia in later life. Considerable advances have been made in developing mouse models that recapitulate, to varying extents, the development of human tau pathology, and the learning and memory deficits characteristic of some tauopathies. Furthermore, such models have been used to show promising disease-modifying effects in pre-clinical testing of new therapeutics. Various strategies have been utilised to generate mouse models of tauopathies. Some of the most enlightening models developed to date either constitutively or inducibly express pathogenic tau mutations. These animals have been instrumental in defining critical disease-related mechanisms, including the observation that tangles are not the toxic form of tau in disease. Here, we discuss the strengths and weaknesses of well characterised transgenic models that emulate human tauopathy, and include a comprehensive listing of the main phenotypic characteristics of all reported tau transgenic rodents. We summarise the use of tau mice for the development and evaluation of new therapeutic approaches, and their utility in identifying novel drug targets. In addition, we review the parameters to be considered in the development of the next generation of mouse models of tauopathy, aimed at further increasing our understanding of disease aetiology and in evaluating novel treatments.

RNA and protein-dependent mechanisms in tauopathies: consequences for therapeutic strategies

Tauopathies are a group of neurodegenerative diseases characterised by intracellular deposits of the microtubule-associated protein tau. The most typical example of a tauopathy is Alzheimer's disease. The importance of tau in neuronal dysfunction and degeneration has been demonstrated by the discovery of dominant mutations in the MAPT gene, encoding tau, in some rare dementias. Recent developments have shed light on the significance of tau phosphorylation and aggregation in pathogenesis. Furthermore, emerging evidence reveals the central role played by tau pre-mRNA processing in tauopathies. The present review focuses on the current understanding of tau-dependent pathogenic mechanisms and how realistic therapies for tauopathies can be developed.

Long-term sexual co-habitation offers no protection from hypertensive disease of pregnancy

Long-term sexual co-habitation and previous pregnancies are thought to protect against the development of hypertensive disease of pregnancy. In order to test the hypothesis that pregnancies conceived after prolonged exposure to the partner's spermatozoa have reduced rates of hypertensive disease this study examined the outcomes of pregnancies of women who conceived by donor insemination as compared with women who conceived after IVF with partner's spermatozoa. This was a retrospective cohort study of 218 women attending an IVF clinic, 45 of whom conceived by donor insemination and 173 of whom conceived by partner's spermatozoa. Cases were identified from the IVF unit and data were extracted from patients' notes by blinded observers. Results showed no difference between the groups, with 22% of women who conceived with donor spermatozoa and 24% who conceived with partner spermatozoa developing some form of hypertensive disease of pregnancy. Insemination by partner's spermatozoa was not associated with a reduction of hypertensive disease and neither was donor spermatozoa associated with an increased incidence.

Cytokine expression during allergen-induced late nasal responses: IL-4 and IL-5 mRNA is expressed early (at 6 h) predominantly by eosinophils

The production of TH2-type cytokines [interleukin-4 (IL-4) and IL-5] and tissue eosinophilia are characteristic features of allergic diseases. It was previously reported that at 24 h after allergen provocation, CD3+ T-lymphocytes were the principal cell source of IL-4 and IL-5 mRNA transcripts in both atopic asthma and rhinitis. To investigate whether IL-4 and IL-5 mRNA are expressed earlier during late nasal responses and if so, which cell(s) are responsible. Nasal biopsies were obtained at 6 h after nasal allergen challenge and following a control challenge with the allergen diluent. Sections were immunostained for T-lymphocytes (CD3+, CD4+) and eosinophils (EG2+). In situ hybridization was used to detect the number of cells expressing messenger RNA (mRNA) for IL-4 and IL-5. In patients with allergic rhinitis, eosinophils (EG2+ cells P = 0. 006) but not T- cells (CD3+ cells) increased in the nasal mucosa at 6 h after allergen challenge. The number of cells expressing IL-4 mRNA (P = 0.01) and IL-5 mRNA (P = 0.05) also increased at 6 h. Co-localization studies showed that 76% of IL-4 mRNA+ cells and 77% of IL-5 mRNA+ cells were eosinophils, whereas at this time point, T-cells and mast cells accounted for </=5% of mRNA expression; the identity of the remaining 20% of IL-4 and IL-5 mRNA+ cells was not determined. By use of immunohistology, cytokine protein expression at 6 h was confirmed for IL-4 but not for IL-5. No increases in T-cells, eosinophils or cytokine expression were detected in non-atopic subjects. Eosinophils represent an early source of IL-4 which may contribute to TH2-type responses during late nasal responses and ongoing allergic rhinitis.

Self-reports about tinnitus and about cochlear implants

OBJECTIVE

Analyze literature on self-report outcomes in two areas of audiological rehabilitation: 1) tinnitus and 2) cochlear implant hearing aids.

DESIGN

1) Tinnitus: survey of features in the development of self-report approaches and of formal scales used in assessment of tinnitus disability and handicaps. 2) Cochlear implants: summary of the literature using self-report approaches to cochlear implant experience that indicates points of theoretical significance.

RESULTS

1) Major features of tinnitus are: a) disabilities such as interference with and distortion of normal auditory perception; b) handicaps such as emotional distress, interference with sleep, and with personal and social life. Nonauditory factors-chronic depression, high self-focused attention-mediate the degree of experienced tinnitus handicap. 2) People with prelingual loss of hearing report that a cochlear implant primarily enables improved detection and discrimination of environmental sound; those with postlingual loss find that an implant in addition provides improved speech recognition.

CONCLUSIONS

1) Coping with tinnitus is influenced by the personal resources that can be brought to bear on the experience, highlighting a general point that any rehabilitation outcome is not only a matter of acoustical solutions. By the same token, tinnitus can be easier to cope with if its "psychoacoustic presence" can be diminished by some form of masking. 2) Cochlear implants fitted in childhood that do not provide meaningful input signals in real-world settings may be rejected in adolescence. 3) "Hearing," as a capacity, does not have a fixed worth. Different circumstances mean it will be taken as desirable or as delivering torment (extreme tinnitus, e.g.). Its value will also vary depending on the extent of a person's access to spoken language (aiding in very early childhood, e.g.).

Optimal outcome measures, research priorities, and international cooperation

The participants in the Eriksholm Workshop on "Measuring Outcomes in Audiological Rehabilitation Using Hearing Aids" debated three issues that are reported in this article. First, it was agreed that the characteristics of an optimal outcome measure vary as a function of the purpose of the measurement. Potential characteristics of outcome self-report tools for four common goals of outcome measurement are briefly presented to illustrate this point. Second, 10 important research priorities in outcome measurement were identified and ranked. They are presented with brief discussion of the top five. Third, the concept of generating a brief universally applicable outcome measure was endorsed. This brief data set is intended to supplement existing outcome measures and to promote data combination and comparison across different social, cultural, and health-care delivery systems. A set of seven core items is proposed for further study.

Glandular abnormalities on cervical smear: a study to compare the accuracy of cytological diagnosis with underlying pathology

The interpretation of glandular abnormalities detected by cervical smear provides a diagnostic dilemma. This study aims to compare the accuracy of cytological diagnosis with underlying pathology so that guidelines for the investigation and management of abnormal glandular smears may be formulated. A retrospective review of 150 women with glandular abnormalities reported on cervical smear collected over 12 months from 1996 in a University hospital was performed. Smears were graded by the initial report into 3 groups, dependent on the severity of abnormality. Investigation, treatment and subsequent 3-year follow-up were recorded. The accuracy of prediction for a significant neoplastic or preneoplastic glandular pathology only was 0% with mild, 9% (3/35) with moderate, and 24% (9/38) with severe abnormalities. When squamous lesions were included, the chance of finding any dysplastic squamous or glandular abnormality was 16% (12/77), 51% (18/35) and 82% (31/38), respectively, following a smear showing a suspected glandular abnormality only. Our results highlight the poor specificity of predicting glandular neoplasia or preneoplasia from cervical smears, with a final diagnosis of high grade CIN in 35% (17/49) of patients with dyskaryotic glandular cytological changes only and 83% (20/24) where concomitant squamous dyskaryosis was reported. The reporting of reactive or minor changes in endocervical cells was of no diagnostic value. Management protocols for moderate and severe glandular abnormalities should include visualisation and biopsy of the uterine cavity to exclude endometrial neoplasia.

Long-term clinical efficacy of grass-pollen immunotherapy

BACKGROUND

Pollen immunotherapy is effective in selected patients with IgE-mediated seasonal allergic rhinitis, although it is questionable whether there is long-term benefit after the discontinuation of treatment.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of the discontinuation of immunotherapy for grass-pollen allergy in patients in whom three to four years of this treatment had previously been shown to be effective. During the three years of this trial, primary outcome measures were scores for seasonal symptoms and the use of rescue medication. Objective measures included the immediate conjunctival response and the immediate and late skin responses to allergen challenge. Cutaneous-biopsy specimens obtained 24 hours after intradermal allergen challenge were examined for T-cell infiltration and the presence of cytokine-producing T helper cells (TH2 cells) (as evidenced by the presence of interleukin-4 messenger RNA). A matched group of patients with hay fever who had not received immunotherapy was followed as a control for the natural course of the disease.

RESULTS

Scores for seasonal symptoms and the use of rescue antiallergic medication, which included short courses of prednisolone, remained low after the discontinuation of immunotherapy, and there was no significant difference between patients who continued immunotherapy and those who discontinued it. Symptom scores in both treatment groups (median areas under the curve in 1995, 921 for continuation of immunotherapy and 504 for discontinuation of immunotherapy; P=0.60) were markedly lower than those in the group that had not received immunotherapy (median value in 1995, 2863). Although there was a tendency for immediate sensitivity to allergen to return late after discontinuation, there was a sustained reduction in the late skin response and associated CD3+ T-cell infiltration and interleukin-4 messenger RNA expression.

CONCLUSIONS

Immunotherapy for grass-pollen allergy for three to four years induces prolonged clinical remission accompanied by a persistent alteration in immunologic reactivity.

Open earmold fittings for improving aided auditory localization for sensorineural hearing losses with good high-frequency hearing

OBJECTIVE

We tested the hypothesis that the use of nonoccluding earmolds for hearing aid fittings could optimize auditory localization in the vertical plane for people with moderate, low-frequency hearing losses and good hearing at frequencies above 4000 Hz. This benefit was expected to arise from leaving the pinna unobstructed and by optimizing hearing (unaided) for frequencies above the hearing aid's limit.

DESIGN

Twenty-two participants had hearing losses greater than 30 dB over the range 250 to 2000 Hz and had minimal losses (< 30 dB) at 6000 Hz and 8000 Hz. Their auditory localization was tested, using a horizontal arc and a vertical arc of loudspeakers, when listening unaided and when fitted bilaterally with Behind The Ear hearing aids with three earmold types--closed (occluded), open (partly occluded), sleeve (nonoccluded).

RESULTS

Localization of vertical plane sound sources was significantly poorer for the closed earmold condition than for unaided. The open and sleeve conditions were better than the closed condition, and, for the sleeve earmold, vertical localization was almost equal to that unaided. The capacity to benefit from using open rather than closed earmolds was related to hearing level; people with the best hearing at 4000, 6000, and 8000 Hz received the most benefit. There was limited evidence that open earmolds also can be advantageous for some aspects of horizontal plane localization.

CONCLUSIONS

Nonoccluding earmolds optimize aided vertical localization for hearing aid users with good high-frequency hearing. The "sleeve" earmold, so far used only in research, may be a useful clinical option.

Improvement in aided sound localization with open earmolds: observations in people with high-frequency hearing loss

Sound localization ability was tested in nine people with marked, bilateral, high-frequency hearing loss and little or no low-frequency loss. They had previously been fitted bilaterally with behind-the-ear hearing aids and closed earmolds and showed poorer aided than unaided localization performance. Further testing was conducted in unaided and aided conditions, with the aids coupled to closed, open, and "sleeve" (extra-open) earmolds. Closed earmolds affected localization, particularly in the frontal horizontal plane, but performance was restored to unaided levels in both of the open earmold conditions. In the lateral vertical plane, localization was found to correlate with the extent of difference between low- and high-frequency hearing levels. That result is discussed in terms of a dynamic, low-frequency localization cue. Open earmolds are argued to improve aided sound localization for the present sample by permitting undistorted access to low-frequency interaural time/phase differences.

The effect of head rotations on vertical plane sound localization

Current understanding gives predominant weight to stationary cues for auditory localization. Two experiments were conducted to investigate the possible existence of a dynamic cue. The first experiment involved localization of concealed sources in the upper median vertical plane (MVP) and showed, as expected, that elevation was not detectable with motionless listening when high-frequency energy was absent or when normal pinna function was distorted. Elevation under such conditions did become detectable with horizontal head rotations, provided low-frequency energy was present in the signal. This indicates that the basis of the dynamic cue is variation in the rate of transformation of low-frequency interaural time/phase differences. The second experiment involved localization of sources arrayed throughout upper and lower regions of the MVP and in the left lateral vertical plane (LVP); it showed that upper hemisphere sources can be distinguished somewhat from those in the lower hemisphere, even in motionless listening conditions, but more so with rotation. The greatest benefit for localization from rotation of the head appears to be gained for sources positioned in the front MVP.

Auditory localization, detection of spatial separateness, and speech hearing in noise by hearing impaired listeners

In two groups, one with sensorineural and the other with conductive-mixed hearing loss, measures were made of single-source localization and speech intelligibility in both spatially separate and nonseparate noise. There was also a test for detecting when two sounds came from the same location or from separate ones. Localization test results confirmed earlier findings, namely, disruption of vertical plane ability generally, and a further, particular disturbance to horizontal plane localization in the conductive-mixed group. Compared with a normal control group, there were only slight signs of benefit from separation of speech and noise in the region lateral to the listener, and virtually none in the frontal region. The new test, spatial separateness, had elements in common with both of the other tests, and links were observed from localization to separateness detection, and from separateness to benefit from separation of speech and noise. Localization was also related to speech hearing in nonspatially separated noise.

The contribution of head motion cues to localization of low-pass noise

Localization of low-pass sounds was tested in relation to aspects of Wallach's (1939, 1940) hypotheses about the role of head movement in front/back and elevation discrimination. With a 3-sec signal, free movement of the head offered only small advantage over a single rotation through 45 degrees for detecting elevation differences. Very slight rotation, as observed using a 0.5-sec signal, seemed sufficient to prevent front/back confusion. Cluster analysis showed that, in detecting elevation, some listeners benefited from rotation, some benefited from natural movement, and some from both. Evidence was found indicating that a moving auditory system generates information for the whereabouts of sounds, even when the movement does not result in the listener facing the source. Results offer significant if partial support for Wallach's hypotheses.

Effects of earmold type on ability to locate sounds when wearing hearing aids

OBJECTIVE

To determine whether the choice of earmold type can affect aided auditory localization.

HYPOTHESES

1) for sensorineural hearing losses with good low-frequency hearing (Low group, n = 10), the use of open earmolds could avoid decrements in horizontal plane localization found with closed (occluding) earmolds; 2) for sensorineural losses with good high-frequency hearing (High group, n = 12), the use of open earmolds could result in better vertical plane localization than could the use of closed earmolds; and 3) for conductive/mixed hearing losses (CM group, n = 19), the choice of earmold type-hard short, soft short, or soft long-could affect aided localization.

DESIGN

Aided and unaided auditory localization was tested for the above three groups of hearing-impaired listeners when wearing bilaterally fitted hearing aids.

RESULTS

For the Low group, results were inconclusive because nine listeners showed virtually perfect horizontal localization with both closed and open earmolds. For the High group, two listeners showed improved vertical plane localization with open earmolds. These were the only listeners with HTLs of 30 dB or better at 6000 Hz and 8000 Hz. For the CM group, aided horizontal plane localization was significantly better than unaided localization for about half of the listeners and was similar for the other half. There was no significant group difference for the three earmold types. For some individuals, one earmold type was better than the others.

CONCLUSIONS

The choice of earmold can effect aided localization, but the specific effects need further elucidation. Audiologists should be aware that people with conductive or mixed hearing losses may have poor auditory localization and that this may be improved by the fitting of hearing aids.

Disabilities and handicaps associated with impaired auditory localization

A questionnaire on (1) difficulties in everyday sound localization (localization disabilities), (2) limitations and disadvantages related to such disabilities (localization handicaps), and (3) everyday speech hearing disabilities was completed by 104 people with symmetrical hearing losses. Respondents considered situations when listening with and without their usual hearing aid fittings. The hearing-impaired group rated their unaided localization ability as significantly poorer than a sample with no reported hearing loss, particularly discrimination of distance. Only slight limitations on everyday activity due to localization disability were found, but disadvantage was reported in the form of experiences of confusion of sounds, of resultant loss of concentration, and of a wish to escape settings where this occurred. There was a moderate correlation between localization and speech hearing, even when hearing level was controlled for. Aided listening, whether with one or with two hearing aids, was reported as enabling significant improvements in both functions.

Available response choices affect localization of sound

Successful replication of an experiment by Butler and Humanski (1992) showed that listeners are able to proficiently localize sources on a lateral vertical plane on the basis of interaural differences alone. When a lateral horizontal array was included in the test setup, that finding was replicated only for a broadband signal interacting with the pinna, not for ones (lowpass and pure tone) providing only interaural differences. Cross-plane errors conforming to "cones of confusion" were observed for those latter sounds. In a second experiment, response options were made more unconstrained, which clarified the nature of the cross-plane confusions. Lowpass signals from lateral vertical plane sources tend to be heard at or close to the horizon. Measurement of cue values needs to take account of the response options available to listeners, as well as signal properties.

An ecological approach to disability and handicap in relation to impaired hearing

A contrast of perspectives can be witnessed in individualist versus collectivist approaches to the definition of handicap resulting from hearing impairments and disabilities. The individualist approach tends to neglect the possibility of intervention at the level of the environment of the person with impaired hearing, while the collectivist approach tends to neglect the adaptations the individual may make to overcome hearing difficulties. An ecological approach is advocated giving attention to the system of interactions, both disabling and enabling, among various components: persons, environments and interfaces. Implications for audiological practice are indicated under several headings, ranging from physical and social environmental interventions to evaluation of individual needs.

Effects on sound localization of configuration and type of hearing impairment

Localization ability of 87 bilaterally hearing-impaired listeners was tested in the horizontal and vertical planes, frontally and laterally. In those with sensorineural hearing loss, it was found that deficits in localization accuracy in different regions of auditory space could be related to different configurations of hearing loss. For example, there were associations between vertical plane discrimination and high-frequency sensitivity; and front-rear discrimination and mid-to-high-frequency sensitivity. These results agree with theoretical expectations, while the outcome overall contrasts with previous reports that localization performance is unrelated to audiometric configuration. A comparison of 13 listeners with conductive/mixed types of impairment with a sensorineural-loss group, matched for degree of loss, showed that a conductive component adds significantly to localization disturbance, particularly in the horizontal plane. The probable reason is a disturbance of low-frequency interaural time cues, and this occurs because a higher proportion of low-frequency sound is likely to be transmitted via bone conduction relative to air conduction. Correlations between hearing loss and localization are only moderate, suggesting that aspects of hearing impairment, in addition to simple attenuation, may also reduce auditory localization performance.

Effects of long-term bilateral and unilateral fitting of different hearing aid types on the ability to locate sounds

Aided localization ability of 87 hearing-impaired listeners was tested for horizontal and vertical sound sources, at two signal levels, and for two orientations to the loudspeaker array (facing, sideways). Some listeners wore behind-the-ear (BTE) aids, others in-the-ear (ITE) aids. Some were bilaterally fitted, others unilaterally fitted. Listeners were tested only with types of aids and fittings that they were accustomed to wearing. The results strongly supported bilateral fitting for moderately and severely hearing-impaired listeners. However, for mildly impaired listeners, those fitted unilaterally performed as well, on average, as those fitted bilaterally. This suggests a need to consider individual listening requirements and also to provide such listeners with experience in unilaterally-aided listening before assessing the possible advantages of bilateral fitting. When hearing level was controlled, there was no overall difference in the performance of ITE and BTE aid wearers. This discrepancy with other research may be explained by measures (removal of intensity cues, permitting of head movement) designed to make the test situation more representative of real-life listening.

Auditory localization under conditions of unilateral fitting of different hearing aid systems

The spatial localization function of hearing-impaired listeners, usually fitted bilaterally with BTE, ITE or ITC devices, was tested under conditions of unilateral fitting of each of their own hearing aids, and unilateral fitting of stock versions of each of the other types. For the BTE wearers average localization accuracy and individual variability were not greatly changed when wearing only their left ear device, compared with bilateral aided performance. In ITE wearers, unilateral fitting in either ear led to somewhat poorer performance than bilateral. In the ITC wearers unilateral fitting produced inconsistent outcomes. Both BTE and ITE wearers fared poorly when fitted unilaterally with stock forms of devices 'foreign' to them, whereas ITC wearers did not show such a contrasting outcome. A group of non-impaired listeners showed severe disruption of localization under unilateral BTE and ITC hearing aid conditions, and to a lesser extent with ITEs. Results for the hearing-impaired listeners are interpreted in terms of adaptation to different usage patterns, with BTE wearers suggested as having adapted to their own systems unilaterally as well as bilaterally.

A comparison of different binaural hearing aid systems for sound localization in the horizontal and vertical planes

Three groups of hearing-impaired listeners who had been fitted binaurally with behind-the-ear (BTE), in-the-ear (ITE), or in-the-ear-canal (ITC) hearing aids were tested on spatial localization function for sources in the frontal horizontal and vertical planes. No significant differences in unaided performance were observed between the groups, nor between that and aided performance in the BTE and ITE wearers. ITC wearers, by contrast, showed a deterioration in aided over unaided performance. From observations of performance when each group wore temporary fittings of the other two types of system, and from the performance of a non-impaired control group, it appears that the performance decrement for the ITC wearers was due to their own particular systems although specific reasons for this decrement could not be identified. In all conditions, aided and unaided, vertical plane localization was markedly disrupted in all the hearing impaired groups. It was also disrupted, to a lesser but still substantial extent, in aided conditions for the non-impaired listeners.

The effect of various hearing protectors on sound localization in the horizontal and vertical planes

Listeners were tested under free head/torso movement conditions, using a brief pulsed broadband noise signal presented from any 1 of 20 loudspeakers in two intersecting hemicircumferential arrays: one in the horizontal plane, one in the vertical. The listeners' task was to judge the whereabouts of each signal while listening in normal, open-ears conditions or while wearing various types of standard or electronic earmuffs or compressible foam earplugs. Results showed that listeners could accomplish the task successfully in normal (open-ear) conditions. Results using earplugs, nonelectronic earmuffs, and two types of dichotic (dual microphone) electronic earmuffs showed decrements in performance similar to each other. These decrements took the general form of loss of appreciation of the vertical plane and of front-rear differences in the horizontal plane. Lateral discrimination was blurred but otherwise intact. Of two diotic (single microphone) electronic earmuffs, one completely disrupted localization function and the other came close to it.

Staff carriage of epidemic methicillin-resistant Staphylococcus aureus

Twenty-six nurses were repeatedly screened for carriage of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) immediately before and after duty periods in which they solely attended six patients widely colonized with two EMRSA strains distinguishable by plasmid analysis. EMRSA carriage was detected in 13 nurses. Three EMRSA carriage patterns emerged: transient carriage in 12 nurses, when the EMRSA was isolated from noses or fingers of nurses after duty but was gone before their next day's duty; short-term nasal carriage, seen on occasion in 4 of these 12 nurses, when EMRSA carriage was detected on two consecutive screens; and persistent nasal carriage, seen in 1 nurse only, when the EMRSA was seen on more than two consecutive occasions. All but one of these incidents of carriage could be explained by close patient, rather than environmental, exposure and occurred despite an intensive control programme. Transient or short-term carriage in nurses probably resulted in transfer of the EMRSA between patients. Staff decontamination should be considered following a period of cohort nursing of EMRSA patients, especially if staff members are shortly to nurse unaffected patients. Our findings may explain some of the difficulties in controlling EMRSA.

Generation 04 sodium slides and generation 04 reference fluid evaluated for use with the Ektachem 400 Analyzer

Evaluation of a new generation of sodium slides and reference fluid for use with the Kodak Ektachem 400 Analyzer demonstrated improved performance in generation 04 over the previous generation 03 slide for sodium determinations. A decrease in between-replicate imprecision and a correction of the "serum" assigned values of the calibrators used to calibrate the slide used with the reference fluid account for the improvement. When generation 04/Ektachem results (y) were compared with results obtained with a Beckman ion-selective electrode (x), linear regression statistics were: slope = 0.88, y-intercept = 15.4 mmol/L, and Syx = 2.1 mmol/L. The average fixed bias in comparison with the Beckman electrode decreased from +1.9 mmol/L with generation 03 to -0.6 mmol/L with generation 04 materials. Random error is indicated by a decrease in Syx from 2.8 mmol/L for generation 03 to 2.1 mmol/L for generation 04. Application of Deming's regression, a more accurate portrayal of the generation 04 sodium data set, produces a slope of 1.0 and a y-intercept of -0.6 mmol/L.

Generation 04 sodium slides and generation 04 reference fluid evaluated for use with the Ektachem 400 Analyzer

Evaluation of a new generation of sodium slides and reference fluid for use with the Kodak Ektachem 400 Analyzer demonstrated improved performance in generation 04 over the previous generation 03 slide for sodium determinations. A decrease in between-replicate imprecision and a correction of the "serum" assigned values of the calibrators used to calibrate the slide used with the reference fluid account for the improvement. When generation 04/Ektachem results (y) were compared with results obtained with a Beckman ion-selective electrode (x), linear regression statistics were: slope = 0.88, y-intercept = 15.4 mmol/L, and Syx = 2.1 mmol/L. The average fixed bias in comparison with the Beckman electrode decreased from +1.9 mmol/L with generation 03 to -0.6 mmol/L with generation 04 materials. Random error is indicated by a decrease in Syx from 2.8 mmol/L for generation 03 to 2.1 mmol/L for generation 04. Application of Deming's regression, a more accurate portrayal of the generation 04 sodium data set, produces a slope of 1.0 and a y-intercept of -0.6 mmol/L.

Skin as a source for hospital infection

The skin is itself the site of infection by many different bacteria. Dermatologists may see primary skin infection due toStaphylococcus aureus, beta hemolytic streptococci and a host of less common pathogens including gonococci, mycobacteria and even enterobacteriaceae, or secondary infection which is mostly staphylococcal in eczema or weighted toward Proteus and Pseudomonas in venous stasis ulcers. Geriatricians see a mixed microbial flora in decubitus ulcers while those who insert plastic prostheses, intravenous or abdominal catheters can expect infection with coagulase-negative or positive cocci.

The skin also forms a natural reservoir of organisms available to infect a variety of patients and it is with the skin as a reservoir that this article is concerned. The normal flora of the skin in healthy subjects is composed chiefly of coagulase-negative cocci and coryneforms with gram-negative bacilli chiefly, but not entirely, represented by Acinetobacter. Patients admitted to the hospital who are severely ill may become more heavily colonized by gram-negative bacilli while frank skin lesions constitute a more obvious source of potential pathogens.

Occupational deafness: the continuing challenge of early German and Scottish research

Systematic studies in occupational deafness were first carried out in the late 19th century, in America, Germany, Russia, and Scotland. The studies by Gottstein and Kayser, in 1881 in Germany, and by Barr, in 1886 in Scotland, are identified as the two principal landmarks. The physicians who carried them out should be seen as occupying a place in the mainstream of development of industrial medicine. Gottstein and Kayser's study of personnel in a railway works reflected a contemporary concern about railway safety; Barr's, of boilermakers, a feeling for the difficulties in hearing in the everyday world experienced by the victims of occupational deafness. Barr's evaluation of such difficulties through self-report, we argue, reveals more of the quality of hearing handicap than the present century's apparently objective tests. Both studies relied on occupation-based epidemiology, which was able to identify occupational deafness, distinguish its etiology, and locate the site of its pathology. We argue that occupation-based epidemiology has since been neglected in favour of dose-response epidemiology to the detriment of research in occupational deafness and in industrial medicine generally. Dose-response epidemiology seems the more scientific but, in practice, it is afflicted by even more uncertainty than occupation-based epidemiology. To compound the uncertainty, there are two incompatible mathematical expressions for the dose-response relation for noise, both separately enshrined in legislation in various parts of the world. We conclude by advocating more secondary research in industrial medicine. Barr points us to a further topic for such research, the place of temporary threshold shift in the development of knowledge about occupational deafness as a problem for industrial medicine.

Hearing, hearing impairment, and the audible world: a theoretical essay

In contrast to traditional understandings about hearing, based on physics and physiology, the ecological model permits development of a perspective on hearing in relation to the audible features and characteristics of the real, day-to-day world. An ecological account, furthermore, addresses the perceiver's role more adequately, allowing the description of 'hearing acts' typically undertaken in relation to the audible world. The affordances or utilities of the audible world for the normally hearing perceiver having been understood - and the most crucial affordance is ongoing sustainment of social selves - a model of the hearing-impaired actor is advanced that incorporates the concept of 'management of spoiled identity'. The implications for practitioners' attitudes in assessment and rehabilitation are discussed.

Effect of oxprenolol on some fear-induced behavioral responses and hyperthermia in rats subjected to inescapable shocks

The effect of oxprenolol (100 mg/kg p.o.) on the development of hyperthermia in a shock enclosure and on exploratory and grooming responses in an exploration box, was investigated in rats subjected to inescapable shocks once daily for 5 days. The hyperthermic response of shocked rats was found to be significantly reduced by oxprenolol treatment. Exploratory behavior, which was suppressed by previous exposure to shocks, was not influenced by oxprenolol. However, under oxprenolol treatment grooming diminished from the first day of the trial onward, both in duration and frequency, as though habituation had occurred. The results are interpreted as evidence of partial effectiveness of oxprenolol in suppressing fear-induced somatic and behavioral manifestations.