GABAergic neural activity involved in salicylate-induced auditory cortex gain enhancement.

Although high doses of sodium salicylate impair cochlear function, it paradoxically enhances sound-evoked activity in the auditory cortex (AC) and augments acoustic startle reflex responses, neural and behavioral metrics associated with hyperexcitability and hyperacusis. To explore the neural mechanisms underlying salicylate (SS)-induced hyperexcitability and "increased central gain," we examined the effects of GABA receptor agonists and antagonists on SS-induced hyperexcitability in the AC and startle reflex responses. Consistent with our previous findings, local or systemic application of SS significantly increased the amplitude of sound-evoked AC neural activity, but generally reduced spontaneous activity in the AC. Systemic injection of SS also significantly increased the acoustic startle reflex. S-baclofen or R-baclofen, GABA-B agonists, which suppressed sound-evoked AC neural firing rate and local field potentials, also suppressed the SS-induced enhancement of the AC field potential and the acoustic startle reflex. Local application of vigabatrin, which enhances GABA concentration in the brain, suppressed the SS-induced enhancement of AC firing rate. Systemic injection of vigabatrin also reduced the SS-induced enhancement of acoustic startle reflex. Collectively, these results suggest that the sound-evoked behavioral and neural hyperactivity induced by SS may arise from a SS-induced suppression of GABAergic inhibition in the AC.

Consensus for tinnitus patient assessment and treatment outcome measurement: Tinnitus Research Initiative meeting, Regensburg, July 2006.

There is widespread recognition that consistency between research centres in the ways that patients with tinnitus are assessed and outcomes following interventions are measured would facilitate more effective co-operation and more meaningful evaluations and comparisons of outcomes. At the first Tinnitus Research Initiative meeting held in Regensburg in July 2006 an attempt was made through workshops to gain a consensus both for patient assessments and for outcome measurements. It is hoped that this will contribute towards better cooperation between research centres in finding and evaluating treatments for tinnitus by allowing better comparability between studies.

Trends in oral surgery in England and Wales 1991-2000.

OBJECTIVE: To investigate trends in oral surgery in England and Wales 1991-2000. METHODS: Oral surgery procedure data were derived from Dental Practice Board and Department of Health Hospital Episode Statistics. RESULTS: There was a 6% increase in minor oral surgery (MOS) procedures, including ordinary extractions, extractions of special difficulty, apicectomies and third molar removals, carried out in the General Dental Services (GDS) but the number of third molars removed fell by 32% after 1997. General anaesthetics (GA) administered in the GDS fell by 77% and the number of sedations rose 54% after 1998. There was concentration of minor oral surgery in practices: in the year 2000, 88% of practitioners carried out less than five third molar removals. In the Hospital Dental Service (HDS) there was a 98% increase in day surgery, and a 53% decrease in ordinary admissions for minor oral surgery. HDS waiting times remained constant over the ten year period. CONCLUSIONS: The principal trends were substantial decreases in apicectomies, third molar removals after 1997 and GAs after 1998; increases in extractions of special difficulty and concentration of MOS in the GODS. Numbers of ordinary extractions did not change. In the HDS there was a large shift from in-patient to daycase provision which has facilitated expansion of maxillofacial surgery. This is an important example of NHS reconfiguration. Perhaps the most important implication of these changes concerns the place of MOS in vocational training.

A controlled trial of three referral methods for patients with third molars.

AIM: To evaluate the accuracy, sensitivity and specificity of three primary to secondary care referral strategies. METHOD: Thirty two primary care dental practitioners (GDPs) were randomly allocated one of three referral strategies: current practice (control strategy); a neural network embedded within a computer program and a paper-based clinical algorithm. One hundred and seven patients were assessed for lower third molar treatment: 47, 30 and 30 in each group, respectively. Clinical details were assessed by a panel of experts against a gold standard for third molar removal (the National Institutes of Health criteria). The accuracy, sensitivity, specificity, positive and negative predictive values were calculated for each strategy. RESULTS: The referral decisions made by the GDPs in the control group displayed greater accuracy and sensitivity but poorer specificity (0.83; 0.97; 0.22) compared with the neural network (0.67; 0.56; 0.79) and clinical algorithm (0.73; 0.56; 0.93). CONCLUSIONS: It was concluded that incorporation of the clinical algorithm into primary care was the most appropriate option. The computer neural network performed less well than either current practice or the clinical algorithm.

The minor oral surgery outcome scale: a multi-attribute patient-derived outcome measure.

PURPOSE: The purpose of this study was to produce a clinically useful, patient-derived, minor oral surgery outcome scale. PATIENTS AND METHODS: Seventy-seven consecutive patients scheduled for minor oral surgery were interviewed using semistructured interview techniques to identify those areas of life (domains) that patients believed will be affected by minor oral surgery. These interviews were analyzed by a multidisciplinary panel and a scale based on 5 domains, each with 4 outcome statements was constructed. The domains and outcome statements were weighted in terms of importance by a further consecutive sample of 100 patients using resource allocation and visual analog tasks. An additive mathematical formula was applied to the mean weights for each domain and outcome states to produce the final weighted scale. RESULTS: Five domains were identified from the interviews and weighted according to their order of importance (0 to 100 scale; 0 = least important). These were general health and well-being (24.6); impact on home/social life (20.8); health and comfort of the mouth, teeth, and gums (20.0); appearance (18.8); and impact on job/studies (15.8). CONCLUSION: A clinically applicable, multi-attribute outcome scale has been produced that takes into account all determinants of health outcome as perceived by the patient in the context of minor oral surgery. It is completed by selecting a weighted statement from each domain, the sum of which constitutes the patient's health state utility score. The scale has potentially extensive application to both clinical care and research.

The cost, effectiveness and cost effectiveness of removal and retention of asymptomatic, disease free third molars.

PURPOSE OF INVESTIGATION: The study was undertaken to identify the least costly, most effective and most cost-effective management strategy for asymptomatic, disease free mandibular third molars. METHODS AND PATIENTS: A decision tree model of the outcomes of mandibular third molar retention and removal was constructed. Probability data for possible outcomes were obtained from a comprehensive literature review and entered into the decision tree. The cost to the NHS in treating each outcome was calculated. 100 patients attending the oral surgery clinics, University of Wales Dental Hospital rated the effect of each outcome on their own life. The cost and effectiveness data for each outcome were entered into the decision tree and the analyses were conducted by 'folding back' the decision tree based on the probabilities. MAIN FINDINGS: Mandibular third molar retention was less costly (170 Pounds), more effective (69.5 effectiveness units on a 100 point scale) and more cost-effective (2.43 Pounds per unit of effectiveness) than removal (226 Pounds, 63.3 and 3.57 Pounds respectively). These findings were sensitive to changes in the probability of pericoronitis, periodontal disease and caries. PRINCIPAL CONCLUSIONS: Mandibular third molar retention is less costly to the NHS, more effective for the patient and more cost-effective to both parties than removal. However, should the likelihood of developing pericoronitis, periodontal disease and caries increase substantially then removal becomes the more cost-effective strategy.

The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population.

Classical studies have demonstrated genetic heterogeneity for nonsyndromic autosomal recessive congenital neurosensory deafness, with at least six loci postulated. Linkage analysis in two consanguineous Tunisian kindreds has demonstrated that one such deafness locus, DFNB1, maps near chromosome 13 markers D13S175, D13S143, and D13S115. We tested these markers for cosegregation with deafness in 18 New Zealand and 1 Australian nonconsanguineous kindreds, each of which included at least two siblings with nonsyndromic presumed congenital sensorineural deafness and that had a pedigree structure consistent with autosomal recessive inheritance. When all families were combined, a peak two-point lod score of 2.547 (theta = .1) was obtained for D13S175, 0.780 (theta = .2) for D13S143, and 0.664 (theta = .3) for D13S115. While there was no statistically significant evidence for heterogeneity at any of the three loci tested, nine families showed cosegregation of marker haplotypes with deafness. These observations suggest that the DFNB1 locus may make an important contribution to autosomal recessive neurosensory deafness in a Caucasian population. In the nine cosegregating families, phenotypic variation was observed both within sibships (in four families), which indicates that variable expressivity characterizes some genotypes at the DFNB1 locus, and between generations (in two families), which suggests allelic heterogeneity.

Drugs in the treatment of tinnitus.

Many drugs and some foods can cause or aggravate tinnitus in some patients. These substances should be identified and withdrawn. Tinnitus may be improved by the treatment of associated conditions, infections, or hearing loss with appropriate drugs--hypotensives, antibiotics, vasodilators, fluoride or thyroxine. Intravenous lignocaine can temporarily reduce or abolish tinnitus in many patients but can aggravate existing tinnitus in some and may have no effect on others. Analogy with pain of central origin suggests that the beneficial effects of lignocaine (lidocaine) may be due to its anticonvulsant action. Lignocaine is used as a test to distinguish between different mechanisms of tinnitus and to predict responses to oral anticonvulsants. Dramatic responses with lignocaine are usually associated with cochlear hearing loss and often with comparable though less marked responses to oral anticonvulsants. Patients who do not benefit from lignocaine do not respond to oral anticonvulsants. The action of anticonvulsants is often potentiated by tricyclic antidepressants. The majority of patients who respond to lignocaine can also have their tinnitus effectively masked, as predicted, on a tinnitus synthesizer. A small proportion respond to masking and not to lignocaine and a small proportion to lignocaine and not to masking. Beneficial effects of masking and anticonvulsants are cumulative. Anticonvulsants may also produce subjective improvement in clarity, improved tolerance of hearing aids and increased masking benefit when a hearing aid is worn.

Fertility of bull spermatozoa in egg-yolk diluents of varied lipid fatty acid composition.

Three groups of hens were fed a standard egg-production mixture or similar diets enriched with either sunflower oil or beef tallow. The resulting egg yolks were used to prepare bovine semen diluents. Changes in the liquid fatty acid composition of the diluents were demonstrated by gas-liquid chromatography. No significant effects of the treatments were seen on bovine sperm motility after freezing and thawing, or on fertilty.

The use of intravenous lignocaine in the diagnosis and treatment of tinnitus.

The effect of intravenous lignocaine upon the symptom of tinnitus has been assessed in seventy-eight patients and the results correlated with associated hearing loss. Lignocaine appears to be highly effective in suppressing tinnitus in patients with presumed damage or degeneration of the Organ of Corti and is less effective in other groups. It is postulated that tinnitus in patients with Organ of Corti damage is the result of abnormal hyperactivity in the auditory pathway following deafferentation.

Antibiotic treatment of secretory otitis media assessed by impedence audiometry.

Impedence audiometry was used to assess the response to treatment with antibiotics of children with secretory otitis media. Only ears with pressure at maximum compliance of less than --150mm water were included. There was a significant improvement with Bactrim, ampicillin and Vibramycin. There was no change without treatment and deterioration with penicillin.