Estimated prevalence of noise-induced hearing threshold shifts among children 6 to 19 years of age: the Third National Health and Nutrition Examination Survey, 1988-1994, United States.

OBJECTIVE: This analysis estimates the first nationally representative prevalence of noise-induced hearing threshold shifts (NITS) among US children. Historically, NITS has not been considered a common cause of childhood hearing problems. Among children, NITS can be a progressive problem with continued exposure to excessive noise, which can lead to high-frequency sound discrimination difficulties (eg, speech consonants and whistles). METHODS: The Third National Health and Nutrition Examination Survey (NHANES III) was conducted from 1988 to 1994. NHANES III is a national population-based cross-sectional survey with a household interview, audiometric testing at 0.5 to 8 kHz, and compliance testing. A total of 5249 children aged 6 to 19 years completed audiometry and compliance testing for both ears in NHANES III. The criteria used to assess NITS included audiometry indicating a noise notch in at least 1 ear. RESULTS: Of US children 6 to 19 years old, 12.5% (approximately 5.2 million) are estimated to have NITS in 1 or both ears. In the majority of the children meeting NITS criteria, only 1 ear and only 1 frequency are affected. In this analysis, all children identified with NITS passed compliance testing, which essentially rules out middle ear disorders such as conductive hearing loss. The prevalence estimate of NITS differed by sociodemographics, including age and sex. CONCLUSIONS: These findings suggest that children are being exposed to excessive amounts of hazardous levels of noise, and children's hearing is vulnerable to these exposures. These data support the need for research on appropriate hearing conservation methods and for NITS screening programs among school-aged children. Public health interventions such as education, training, audiometric testing, exposure assessment, hearing protection, and noise control when feasible are all components of occupational hearing conservation that could be adapted to children's needs with children-specific research.

The depression in primary care tool kit.

OBJECTIVE: A tool kit was developed to help primary care physicians overcome some of the barriers to recognition and management of depression. METHOD: Tools were collected from a variety of sources, categorized by function, and evaluated on the basis of previously established criteria, with the best tools selected for inclusion in the tool kit. New tools were developed when an adequate tool for a desired function was not available. The tool kit was reviewed and then revised based on the feedback from eleven experts on depression in primary care, five medical directors from health care systems or managed care companies, and eighteen primary care physicians. All eighteen primary care physicians completed a questionnaire after reviewing the tool kit as part of the evaluation process. RESULTS: Only five of the eighteen physicians were using any kind of tool for depression prior to reviewing the tool kit. All eighteen physicians indicated that they were likely to use one or more of the components of the tool kit. On average, physicians indicated they were likely to use 6.5 of the ten types of tools included in the kit. CONCLUSIONS: A depression tool kit containing screening, diagnostic, management planning, and outcomes assessment questionnaires as well as treatment and counseling guidelines, information tables, flow charts, and patient education materials is likely to be well received by primary care physicians. However, its effectiveness may have as much to do with how its use is organized and implemented as it does with the intrinsic value of its components.

Conversion to neoral for neurotoxicity after primary adult liver transplantation under tacrolimus.

BACKGROUND: Neurological complications after orthotopic liver transplantation (OLTX) have remained a major concern in a small proportion of patients. The etiology of these complications is often thought to be multifactorial: the influence of calcineurin inhibitors is occasionally thought to play an important role. When neurotoxicity occurs after OLTX under tacrolimus, it is usually a minor complication and responds readily to a reduction in the dosage of or a temporary withdrawal of tacrolimus. However, neurotoxic complications occasionally do not respond to this conventional process. Neoral is a microemulsion formulation of cyclosporine. It has more consistent pharmacokinetic parameters and improved bioavailability when compared with conventional cyclosporine. The aim of the present report was to evaluate the role of Neoral in OLTX recipients with neurotoxic complication who failed to respond to a reduction in the dosage of tacrolimus. METHOD: Between August 1995 and November 1997, 330 adults (age >18 years) received primary OLTX under tacrolimus-based immunosuppression (mean age 52.6+/-11.4 years). There were 190 men and 140 women. Twenty-three (7%) patients (mean age 53.2+/-11.8 years; 17 men, 6 women) were converted to Neoral (mean 35+/-41 days after OLTX). These patients were followed until June 1998 (mean follow-up 22.7+/-7.8 months). RESULTS: Four (17.4%) patients died during the follow-up period, and two patients underwent retransplantation. Neurological symptoms improved in all patients who survived. Adequate trough concentrations were achieved in all patients with p.o. Neoral. Nine (39%) patients experienced rejection episodes after conversion. Six (26.1%) patients were converted back to tacrolimus because of ongoing rejection (n=3), retransplantation (n=2), or persistent nausea and vomiting (n=1) without recurrence of the original neurological complication. CONCLUSION: Neurological complications after OLTX disorders that occur under tacrolimus and that fail to respond to a reduction in the dosage can be treated safely by conversion to Neoral. However, the rate of rejection is up to 39%, and patients can often be converted back to tacrolimus without recurrence of the original neurological complication.

Relief of G-protein inhibition of calcium channels and short-term synaptic facilitation in cultured hippocampal neurons.

G-protein inhibition of voltage-gated calcium channels can be transiently relieved by repetitive physiological stimuli. Here, we provide evidence that such relief of inhibition contributes to short-term synaptic plasticity in microisland-cultured hippocampal neurons. With G-protein inhibition induced by the GABA(B) receptor agonist baclofen or the adenosine A1 receptor agonist 2-chloroadenosine, short-term synaptic facilitation emerged during action potential trains. The facilitation decayed with a time constant of approximately 100 msec. However, addition of the calcium channel inhibitor Cd(2+) at 2-3 microM had no such effect and did not alter baseline synaptic depression. As expected of facilitation from relief of channel inhibition, analysis of miniature EPSCs implicated presynaptic modulation, and elevating presynaptic Ca(2+) entry blunted the facilitation. Most telling was the near occlusion of synaptic facilitation after selective blockade of P/Q- but not N-type calcium channels. This was as predicted from experiments using recombinant calcium channels expressed in human embryonic kidney (HEK) 293 cells; we found significantly stronger relief of G-protein inhibition in recombinant P/Q- versus N-type channels during action potential trains. G-protein inhibition in HEK 293 cells was induced via recombinant M2 muscarinic acetylcholine receptors activated by carbachol, an acetylcholine analog. Thus, relief of G-protein inhibition appears to produce a novel form of short-term synaptic facilitation in cultured neurons. Similar short-term synaptic plasticity may be present at a wide variety of synapses, as it could occur during autoreceptor inhibition by glutamate or GABA, heterosynaptic inhibition by GABA, tonic adenosine inhibition, and in many other instances.

Prevalence of hearing loss among children 6 to 19 years of age: the Third National Health and Nutrition Examination Survey.

CONTEXT: Hearing loss in children influences the development of communication and behavioral skills, but few studies in the United States have used pure-tone audiometry to derive hearing loss prevalence estimates for children. OBJECTIVE: To describe the prevalence of hearing loss among US children by sociodemographic characteristics, reported hearing loss, and audiometric screening factors. DESIGN: National population-based cross-sectional survey with an in-person interview and audiometric testing at 0.5 to 8 kHz. SETTING/PARTICIPANTS: A total of 6166 children aged 6 to 19 years completed audiometry in the mobile examination center of the Third National Health and Nutrition Examination Survey conducted between 1988 and 1994. MAIN OUTCOME MEASURE: Hearing loss, defined as audiometric threshold values of at least 16-dB hearing level based on a low or high pure-tone average. RESULTS: A total of 14.9% of children had low-frequency or high-frequency hearing loss of at least 16-dB hearing level, 7.1% had low-frequency hearing loss of at least 16-dB hearing level, and 12.7% had high-frequency hearing loss of at least 16-dB hearing level. Most hearing loss was unilateral and slight in severity (16- to 25-dB hearing level). Of those with measured hearing loss, 10.8% were reported to have current hearing loss during the interview. CONCLUSIONS: This analysis indicates that 14.9% of US children have low-frequency or high-frequency hearing loss of at least 16-dB hearing level in 1 or both ears. Among children in elementary, middle, and high school, audiometric screening should include low-frequency and high-frequency testing to detect hearing loss.

Exposure of the US population to environmental tobacco smoke: the Third National Health and Nutrition Examination Survey, 1988 to 1991.

OBJECTIVE: To estimate the extent of exposure of the US population to environmental tobacco smoke and the contribution of the home and workplace environment to environmental tobacco smoke exposure. DESIGN: Nationally representative cross-sectional survey including questionnaire information from persons aged 2 months and older (n=16818) and measurements of serum cotinine (a metabolite of nicotine) from persons aged 4 years and older (n=10642). SETTING/PARTICIPANTS: Participants in the Third National Health and Nutrition Examination Survey, October 25, 1988, to October 21, 1991. RESULTS: Of US children aged 2 months to 11 years, 43% lived in a home with at least 1 smoker, and 37% of adult non-tobacco users lived in a home with at least 1 smoker or reported environmental tobacco smoke exposure at work. Serum cotinine levels indicated more widespread exposure to nictoine. Of non-tobacco users, 87.9% had detectable levels of serum cotinine. Both the number of smokers in the household and the hours exposed at work were significantly and independently associated (P<.001, multiple regression t test) with increased serum cotinine levels. Serum cotinine levels of children, non-Hispanic blacks, and males indicated that these groups had higher exposure to environmental tobacco smoke. Dietary variables showed no consistent association with serum cotinine levels, and dietary contribution to serum cotinine level, if any, appeared to be extremely small. CONCLUSIONS: The high proportion of the population with detectable serum cotinine levels indicates widespread exposure to environmental tobacco smoke in the US population. Both the home and workplace environments significantly contribute to environmental tobacco smoke exposure in the United States.

Psychological side effects of breast cancer screening.

Evaluated the impact of receiving abnormal mammogram results on women's anxiety and breast cancer worries and on their breast self-examination (BSE) frequency and intentions to obtain subsequent mammograms. A telephone survey was conducted with 308 women 50 years old and older approximately 3 months following a screening mammogram. Subjects included women with suspicious abnormal mammograms, nonsuspicious abnormal mammograms, and normal mammograms. Women with suspicious abnormal mammograms exhibited significantly elevated levels of mammography-related anxiety and breast cancer worries that interfered with their moods and functioning, despite the fact that diagnostic work-ups had ruled out breast cancer. Women with moderate levels of impairment in mood or functioning were more likely to practice monthly BSE than women with either high or low levels of impairment. Breast cancer worries, perceived susceptibility to breast cancer, and physician encouragement to get mammograms all exhibited independent positive relationships to mammogram intentions.

Apparent underreporting of cigarette consumption among Mexican American smokers.

To determine the accuracy of self-report of cigarette consumption among Mexican American smokers, we compared self-reported cigarette use and serum cotinine concentrations in a sample of 547 participants in the Hispanic Health and Nutrition Examination Survey (HHANES). We defined underreporting of cigarette use as a cotinine to cigarette-per-day ratio of greater than 0.142 microM/l which represented a substantial discrepancy between self-reported consumption and serum cotinine. Of the 98 men and 97 women who reported smoking one to nine cigarettes/day, 20.4 percent and 24.7 percent, respectively, underreported their cigarette consumption. Underreporting was less common among men and women smoking 10 to 19 cigarettes/day (8.3 percent and 10.8 percent, respectively) and 20 or more cigarettes/day (2.2 percent and 2.9 percent, respectively). Comparison of underreporters to other smokers by demographic characteristics within sex and cigarettes/day categories showed no differences. Differences in cotinine metabolism and extremely efficient smoking are alternative explanations that can not be ruled out with these data. We believe, however, that a proportion of Mexican American light smokers may underreport the quantity of cigarettes smoked per day, and may truly be moderate or heavy smokers.

Factors associated with inadequate cervical cancer screening among lower income primary care patients.

This study identified factors associated with cervical cancer screening patterns among lower income primary care patients. One hundred forty-one women completed a self-administered questionnaire before their medical visit. The results indicated that 71 percent had a Papanicolaou (Pap) test in the past year, 14 percent had one between 1 and 3 years ago, and 15 percent had not had a Pap test for 3 or more years. Advanced age was associated with a reduced likelihood of adequate screening; 21 percent of women aged 50-64 years and 39 percent of those aged 65 years and older had not had a Pap test in the past 3 years. Factors positively associated with screening included perceived susceptibility to cervical cancer and the belief in the efficacy of Pap tests and benefits of screening. Fear of finding cancer was a significant barrier to cervical screening in this population. Of those women who had not been screened adequately, 58 percent were interested in obtaining Pap tests in the primary care setting. The implications for promoting cervical cancer screening in primary care practices are discussed.

Membrane IL-1: IL-1 alpha precursor binds to the plasma membrane via a lectin-like interaction.

Although biologically active IL-1 associated with plasma membrane has been demonstrated in both mouse and man, a biochemical mechanism for membrane anchoring has not been described. We have analyzed the nature of membrane IL-1 in stimulated murine macrophages. We show that it consists of an IL-1 alpha precursor bound to the plasma membrane via a lectin-like interaction that is specifically dissociated with D-mannose. The dissociated IL-1 was detected as both a biological activity and, by immunoprecipitation and SDS-PAGE, as a 33 kDa IL-1 alpha precursor. Treatment of macrophages with D-mannose before fixation depleted detectable IL-1 biological activity associated with the membrane. Pro-IL-1 alpha was glycosylated in these cells, as shown by incorporation of D-[14C]mannose; thus it is likely that a cell surface lectin binds pro-IL-1 via these carbohydrate residues. In addition to anchoring IL-1 precursor to the plasma membrane, this lectin-like interaction may also be important in the overall regulation of IL-1 release.

A study of respiratory effects from exposure to 2.0 ppm formaldehyde in occupationally exposed workers.

It has been suggested that exposure to formaldehyde (FA) induces asthmatic symptomatology. We have previously studied healthy and asthmatic individuals and found that lung function was unaltered by controlled exposures to 2.0 ppm FA with and without mild exercise. Our present study extends these observations to a group of hospital laboratory workers routinely exposed to FA. Fifteen laboratory workers were exposed in double-blind, random sequence to 0 and 2 ppm FA for 40 min in an environmental chamber with temperature and relative humidity held constant at 23 degrees C and 50%, respectively. These exposures were repeated on two more occasions with a 10-min exercise regimen (450 kpm/min) after being in the chamber 5 min. In addition, a symptom diary and measurements of peak expiratory flow rate (PEFR) were recorded for 24 hr after exposure. Lung function remained unaltered for all 4 exposure days; e.g., mean FEV1.0 for the group did not change by more than 3% at any testing time on any exposure day. Also, there were no delayed obstructive changes as measured by PEFR recordings. Symptoms were mild and transient with unusual odor and eye irritation the most frequent complaint. No lower airway symptoms were reported. We conclude that this group of healthy laboratory workers did not experience any acute or delayed lung function changes from exposure to 2.0 ppm FA at rest and with exercise and that irritative symptoms were few.

Short interpregnancy interval: a risk factor for low birthweight.

In a prospective study of 1683 women delivering at Yale-New Haven Hospital during 1980 through 1982, those conceiving within 1-4 months of a prior live birth were at increased risk of delivering a low birthweight (less than 2500 gm) newborn (RR = 5.70, 95% Cl = 0.83, 39.75), as were those conceiving 5-8 months later (RR = 3.25, 95% Cl = 1.02, 10.34), when compared with women conceiving 9 or more months later. Adjustment was made for maternal age, ethnicity, preterm delivery or low birthweight of prior newborn, and cigarette smoking in pregnancy. Gestational age of the second delivery was not affected by interpregnancy interval. These results may explain earlier reports of increased perinatal mortality after short birth intervals.

Viral transduction of c-myc gene in naturally occurring feline leukaemias.

Feline leukaemia virus (FeLV) is epidemiologically associated with induction of the majority of lymphoid tumours of the domestic cat. However, about one-third of these tumours are devoid of exogenous virus or show evidence of virus integration only after tumour outgrowth. To help define the genetic mechanisms of feline lymphomagenesis we have explored here the possibility that cellular oncogenes (c-onc genes) are rearranged in tumour cell DNA. Of 16 FeLV-positive T-cell tumours among 31 naturally occurring lymphomas, 2 showed evidence of recombinant FeLV proviruses containing myc oncogene sequences. One of the two produced a transmissible myc-containing FeLV. In both cases c-myc and its surrounding DNA appeared unaltered. We believe that the association of myc with FeLV may result in its activation and play a part in the development of a significant fraction of cat T-cell lymphomas. Our findings contrast with studies of experimental induction of chicken lymphoma, in which myc activation occurs by retrovirus promoter insertion near c-myc (refs 3-5), rather than by incorporation into virus.

Rehabilitation of the injured runner.

I have attempted to discuss the preventive aspects of running injuries, the use of orthotic devices and their indications, the use of standard physiotherapeutic techniques, medications, injections, and finally surgery in the prevention of running injuries. Return to running and faulty training techniques have also been mentioned.