Involvement of the α7-nicotinic acetylcholine receptors in the anti-inflammatory action of the thymulin-related peptide (PAT).

BACKGROUND AND PURPOSE: Peptide analog of thymulin (PAT) has been shown to have anti-hyperalgesic and anti-inflammatory properties in animal models of inflammation. Recent reports suggest that the peripheral cholinergic system has an anti-inflammatory role mediated by α7-nicotinic acetylcholine receptor (α7-nAChR). Our aim is to investigate whether the action of PAT is mediated, via the cholinergic pathway. EXPERIMENTAL APPROACH: The anti-hyperalgesic and anti-inflammatory action of PAT was assessed in rat models of inflammatory nociceptive hyperactivity (carrageenan and endotoxin) and in a mice air-pouch model for localized inflammation, respectively; the possible attenuation of PAT's effects by pretreatment with the α7-nAchR specific antagonist methyllycaconitine citrate (MLA) was also investigated. In another series of experiments, using two electrode recordings, the effect of PAT on the α7-nAChRs, expressed in Xenopus Oocytes, was also determined. KEY RESULTS: Administration of PAT reversed inflammatory nociceptive hyperactivity and cold and tactile hyperactivity in rats. This effect was partially or totally prevented by MLA, as assessed by different behavioral pain tests. Treatment with PAT also reduced the alteration of cytokines and NGF levels by carrageenan injection in the mouse air pouch model; this effect was partially antagonized by MLA. Electrophysiological recording demonstrated that PAT significantly potentiated the α7-nAchR expressed in Xenopus Oocytes. These effects were not observed when a control peptide, with a reverse sequence (rPAT), was utilized. CONCLUSIONS AND IMPLICATIONS: The behavioral and electrophysiological observations described in this report demonstrate that PAT mediates, at least partially, its anti-inflammatory action by potentiating the α7-nAChR. These results indicate that PAT has a potential for new therapeutic applications as anti-inflammatory and analgesic agent.

High-frequency (10-18 kHz) hearing thresholds: reliability, and effects of age and occupational noise exposure.

The objective was to investigate the reliability and effects of age and noise on high-frequency hearing thresholds. A cross-sectional study was used involving 187 exposed and 52 non-industrial noise-exposed subjects selected randomly from noise-exposed and non-industrial noise-exposed subjects, respectively. Each subject was tested with both conventional-frequency (0.25-8 kHz) and high-frequency (10-18 kHz) audiometry. Test-retest results showed that high-frequency audiometry (HFA) was as reliable as the conventional procedure. Although the inter-subject variation was large, the intra-subject variation was small, indicating that HFA can be used more reliably than the conventional procedure to monitor individual cases over time. Both the hearing threshold at high frequencies and the upper frequency limit deteriorated as a function of age and frequency. The exposed subjects had significantly higher hearing thresholds than the non-exposed subjects at all the high frequencies tested, the difference between the two groups being greatest at 14 kHz. Multivariate analysis indicated that age was the primary predictor and noise exposure the secondary predictor of hearing thresholds in a high frequency range (10-18 kHz). In contrast, multivariate analysis indicated the reverse order-noise exposure as the primary predictor, then age-for a conventional frequency range (0.25-8 kHz). The results of this study suggest that HFA might be used as an early indicator for noise-induced hearing loss and acoustic trauma rather than audiometry at a conventional frequency (4 kHz), particularly for younger groups.

Occupational noise exposure and hearing loss of workers in two plants in eastern Saudi Arabia.

OBJECTIVE: To determine the prevalence of hearing loss associated with occupational noise exposure and other risk factors. DESIGN: A cross-sectional study involving 269 exposed and 99 non-exposed subjects (non-industrial noise exposed subjects) randomly selected. Current noise exposure was estimated using both sound level meter and noise-dosimeter. Past noise exposure was estimated by interview questionnaire. Otoscopic examination and conventional frequency (0.25-8 kHz) audiometry were used to assess the hearing loss in each subject. RESULTS: 75% (202 subjects) from the exposed group were exposed to a daily Leq above the permissible level of 85 dB(A) and most (61%) of these did not and had never used any form of hearing protection. Hearing loss was found to be bilateral and symmetrical in both groups. Bivariate analysis showed a significant hearing loss in the exposed vs non-exposed subjects with a characteristic dip at 4 kHz. Thirty eight percent of exposed subjects had hearing impairment, which was an 8-fold higher rate than that found for non-exposed subjects. Multivariate analysis indicated exposure to noise was the primary, and age the secondary predictor of hearing loss. Odds of hearing impairment were lower for a small sub-group of exposed workers using hearing protection (N=19) in which logistic regression analysis showed the probability of workers adopting hearing protective devices increased with noise exposure, education, and awareness of noise control. Hearing loss was also greater amongst those who used headphones to listen to recorded cassettes. CONCLUSION: Gross occupational exposure to noise has been demonstrated to cause hearing loss and the authors believe that occupational hearing loss in Saudi Arabia is a widespread problem. Strategies of noise assessment and control are introduced which may help improve the work environment.

Nasal bone fracture.

OBJECTIVE: To study fracture nasal bone at King Faisal Hospital University in Al-Khobar from various aspects, to present our experience and to compare the result with previous works. METHODS: A prospective study conducted from January 1997 to May 1998 including all new cases of fracture nasal bone presented at our emergency department. Plain x-ray of the nose is requested for all patients except one in whom pregnancy is suspected. Reduction of fracture nose was carried out 2-7 days post injury by closed technique under general or local anesthesia with application of nasal cast for 2 weeks. Follow-up of those patients in our clinic is evaluated regarding shape, patency and satisfaction. RESULTS: Eighty six patients included in our study with peak incidence at age 1-30 years with male being dominant. Fall down and road traffic accidents were the common cause of fracture nasal bone. The common presentation was swelling and tenderness in all patients followed by deformity (30.5%) nasal obstruction (40%), and deviated nasal septum (15%). Negative x-ray finding was noticed in 30%, and computerized tomography scan was required for evaluating complicated cases. Only 30 patients (35%) required reduction by closed technique, 23% had poor outcome and were considered as failure. CONCLUSION: This paper stresses the importance of early evaluation of fracture nose in order to avoid complications. The diagnosis is made mainly based on clinical judgement. Closed reduction technique under general anesthesia within 2-10 days post injury is the standard treatment if needed. Failure by closed technique can be managed by septorhinoplasty months later.

Quality assurance in an ear, nose and throat department in Saudi Arabia. A surgical audit.

Quality assurance (QA) in health care is being introduced in developing countries also. However, QA still meets resistance from some clinicians. A prospective voluntary surgical audit was set up in the ENT department of a university teaching hospital in Saudi Arabia. Roles, responsibilities and objectives were defined and designated facilities were provided. There were 2125 admissions and 2389 operations in a 3-yr period. The stated objectives were achieved concerning resource management, post-graduate training, and, especially, the successful establishment of surgical audit as an on-going and open-forum activity in a developing country. We conclude that other clinicians can feel encouraged by our positive experience and implement QA.

Middle ear effusion in children: review of recent literature.

Middle Ear Effusion (O.M.E.) is the commonest ear problem among children, with a peak at the age of 2 years. Incidence varies according to geographical location and race variation, environmental and socio-economic factors. The disease is characterized by accumulation of semi-sterile secretion in the middle ear. It is usually due to either a dysfunction of Eustachian tube or of the mucociliary system or both. The most common presenting symptoms are mild to moderate conductive hearing loss, attacks of earache, and deterioration in school. The diagnosis is based on history, clinical findings and hearing assessments. In general, treatment is classified as conservative and surgical. Early screening and health education are the recent concepts advocated, for early detection.

Hearing screening of infants at King Fahd Hospital of the University.

The detection of hearing impairment in neonatal life and prompt intervention prevents the hazards of physical and developmental delay in speech. During a 12-month period between April 1987 and March 1988, the hearing of 151 well babies and 30 high-risk babied aged 6 to 12 months attending the pediatric clinics of King Fahd Hospital of the University (KFHU), Al-Khobar, were screened. The modified Ewing-Stykar test was performed on all babies. Tympanometry, stapedial reflex, and brainstem evoked response (BERA) were carried out in the well babies who failed the screening test and in all high-risk babies. The failure rate was found to be 4.6% and 43.3% and the validity index 71.4% and 92.3% for the well and high-risk babies, respectively. The results of this limited study encourages us to recommend the implementation of this screening test in all the well baby and the high-risk baby clinics in the Kingdom of Saudi Arabia.

Microbiology of postoperative wound infection: a prospective study of 1770 wounds.

A prospective study of postoperative wound infection was carried out over a 12-month period. Intra-operative swabs from the patients' anterior nares, the opened viscus and parietes were cultured using standard bacteriological techniques. Of the 1770 wounds studied, 167 (9.4%) became infected. Wound infection rates, according to clinical wound types, were clean 5.9%, clean-contaminated 10.7%, contaminated 24.3% and dirty 52.9%. The figures according to microbiological wound types were clean 4.7%, and potentially, lightly and heavily contaminated 15.3%, 22.1% and 30.2% respectively. The commonest causative organisms were Staphylococcus aureus 23.7%, Escherichia coli 16.9%, Staphylococcus epidermidis 13.5% and Pseudomonas aeruginosa 13.0%. When isolated intra-operatively, Enterobacter spp., Proteus spp., Klebsiella spp. and P. aeruginosa appeared to have a high probability of causing postoperative wound infection, but the intra-operative isolation of Bacteroides sp. was a poor predictor of subsequent wound infection.

Frontal encephalocele and the nasal cavity.

Congenital encephaloceles are rare lesions which are often present at the occipital region. Occasionally, they are encountered anteriorly where they may erode through the base of the skull or through a congenital defect in it and appear as a nasal polyp. We describe a case of an anterior basal encephalocele which presented with hypertelorism and was mistaken for a nasal polyp.

Perennial rhinitis in Saudi Arabia. A prospective study.

One hundred consecutive patients with perennial rhinitis were examined clinically and by means of a test battery of laboratory investigations in order to clarify the pathogenesis of the disease, and the clinical value of various tests in the assessment of the patients. In 54% of the cases allergy was proven. The most common allergen was Bermuda grass which is found widely distributed in the Eastern Province. In 46% of the cases, allergy could not be demonstrated. Twelve percent had eosinophilic rhinitis. In this study, investigations of blood eosinophils and IgE were found to be of value in the assessment of patients with perennial rhinitis. The possible connection between pollen allergy and perennial rhinitis in Saudi Arabia is discussed.

Sensorineural hearing loss in sickle cell disease patients in Saudi Arabia.

Among the complications of sickle cell disease, sensorineural deafness is well documented in the Western literature; little is known about it in Saudi Arabian patients, in whom the general pattern of the disease has been reported to be "mild," attributed partly to high levels of HbF. The auditory function of 42 patients with sickle cell anemia was evaluated clinically and audiometrically and compared with 27 normal controls. Sensorineural deafness was observed in 10 (23.8%) of our patients.

Saudi Arabic speech audiometry for children.

Phonetically balanced mono and disyllabic Classical Arabic word lists were chosen to construct a Saudi Arabic speech test for children. These words were taken from children's stories. They were first evaluated by primary and pre-school children in the urban and rural areas of the Province and then divided in eight subgroups of 10 words each. The articulation curves obtained from the children with this test material are similar in course and value to that of the German language using similar speech-test material under the same conditions.

The occurrence of indoor allergens in Saudi Arabia.

Investigations on indoor airborne allergens in Saudi Arabia were performed by mold cultures and dust analyses by counter-current immunoelectrophoresis. Twenty fungal genera were isolated, with Aspergillus as the most often encountered. Most of the dust-bound fungi found are ubiquitous and common. Antibodies against Dermatophagoides pteronyssinus, cat- cow- and rat dander, and Cynodon dactylon pollen were used in the dust analyses. Animal antigens were found in five of the ten dust samples. House dust mites were extraordinarily rare. Pollen of Cynodon dactylon (Bermuda grass) was present in nearly all the samples, and in a concurrent clinical study this antigen was found to be the most common cause of perennial rhinitis.

Hearing levels of school children in Dammam.

Eight hundred children were examined clinically and audiometrically at four frequencies in order to evaluate the incidence of hearing loss in school children of Dammam City (Saudi Arabia) and to analyse the aetiological factors and geographical distribution of these hearing-impaired children. This study revealed that 57 (7.12 per cent) children had hearing defects, of whom 53 (92.98 per cent) had conductive, two (3.5 per cent) mixed and two (3.5 per cent) sensorineural deafness. The children had originated from various regions of Saudi Arabia, and the study was able to show a similar distribution of hearing defects throughout the country. Otitis media was found to be the major cause of impaired hearing.

Effects of intramuscular depot-corticosteroid on the nasal mucosa in allergic rhinitis.

Effects of a single intramuscular depot-corticosteroid in allergic rhinitis were studied at clinical and light microscopic levels in Saudi personnel with allergic rhinitis. Clinical studies and biopsies were performed before and after treatment. Following a single intramuscular injection of Depo-Medrol all patients experienced relief and remained symptom-free thereafter for several months. The roentgenographic appearance of the sinuses, eosinophilia of blood and nasal secretion, skin reactivity and the microscopic features exhibited improvement. These findings suggest that a single intramuscular injection of Depo-Medrol is a satisfactory agent for the treatment of allergic rhinitis.

Saudi Arabic speech audiometry.

Phonetically balanced monosyllabic classical Arabic word lists were chosen to construct a Saudi Arabic speech test. These words were taken from primary school books, daily newspapers and children's stories. They were first evaluated by our students for their familiarity and homogeneity and then divided into six sub-groups of 20 words each. The normal speech-audiometric curves obtained from our students (normally hearing subjects) with this material are similar to normal curves obtained with most European and American monosyllabic word lists. The threshold of intelligibility for our test material was also found to be similar to that of most foreign languages using monosyllabic word lists under the same conditions.