Bone fragility contributes to the risk of fracture in children, even after moderate and severe trauma

We prospectively examined whether the relationship between skeletal fragility and fracture risk in children 9.9 +/- 0.3 (SD) yr is affected by trauma level. Bone size relative to body size and humeral vBMD showed similar inverse relationships with fracture risk, irrespective of whether fractures followed slight or moderate/severe trauma.

INTRODUCTION

Fracture risk in childhood is related to underlying skeletal fragility. However, whether this relationship is confined to low-trauma fractures or whether skeletal fragility also contributes to the risk of fracture caused by higher levels of trauma is currently unknown.

MATERIALS AND METHODS

Total body DXA scan results obtained at 9.9 yr of age were linked to reported fractures over the following 2 yr in children from the Avon Longitudinal Study of Parents and Children. DXA scan results that were subsequently derived included total body less head (TBLH) bone size relative to body size (calculated from TBLH area adjusted for height and weight) and humeral volumetric BMD (vBMD; derived from subregional analysis at this site). Trauma level was assigned using the Landin classification based on a questionnaire asking about precipitating causes.

RESULTS

Of the 6204 children with available data, 549 (8.9%) reported at least one fracture over the follow-up period, and trauma level was assigned in 280 as follows: slight trauma, 56.1%; moderate trauma, 41.0%; severe trauma, 2.9%. Compared with children without fractures, after adjustment for age, sex, socioeconomic status, and ethnicity, children with fractures from both slight and moderate/severe trauma had a reduced bone size relative to body size (1133 cm(2) in nonfractured children versus 1112 cm(2) for slight trauma fractures, p < 0.001; 1112 cm(2) for moderate/severe trauma fractures, p = 0.001) and reduced humeral vBMD (0.494 g/cm(3) in nonfractured children versus 0.484 g/cm(3) for slight trauma fractures, p = 0.036; and 0.482 g/cm(3) for moderate/severe trauma fractures, p = 0.016).

CONCLUSIONS

Skeletal fragility contributes to fracture risk in children, not only in fractures caused by slight trauma but also in those that result from moderate or severe trauma.

Association between bone mass and fractures in children: a prospective cohort study

This is the first prospective cohort study of the association between bone mass and fracture risk in childhood. A total of 6213 children 9.9 years of age were followed for 24 months. Results showed an 89% increased risk of fracture per SD decrease in size-adjusted BMC.

INTRODUCTION

Although previous case-control studies have reported that fracture risk in childhood is inversely related to bone mass, this has not been confirmed in prospective studies. Additionally, it remains unclear which constituent(s) of bone mass underlie this association. We carried out a prospective cohort study to examine the relationship between DXA measures in children 9.9 years of age and risk of fracture over the following 2 years.

MATERIALS AND METHODS

Total body DXA scan results obtained at 9.9 years of age were linked to reported fractures over the following 2 years in children from a large birth cohort in southwest England. DXA measures consisted of total body less head (TBLH) BMD, bone area, and BMC, and results of subregional analysis of the humerus. Analyses were adjusted for age, sex, ethnicity, and social position.

RESULTS

Complete data were available on 6213 children. There was a weak inverse relationship between BMD at 9.9 years and subsequent fracture risk (OR per SD decrease = 1.12; 95% CI, 1.02-1.25). In analyses examining the relationship between fracture risk and volumetric BMD, fracture risk was inversely related to BMC adjusted for bone area, height, and weight (OR = 1.89; 95% CI, 1.18-3.04) and to estimated volumetric BMD of the humerus (OR = 1.29; 95% CI, 1.14-1.45). Fracture risk was unrelated to both TBLH and humeral bone area. However, in analyses of the relationship between fracture risk and bone size relative to body size, an inverse association was observed between fracture risk and TBLH area adjusted for height and weight (OR = 1.51; 95% CI, 1.17-1.95).

CONCLUSIONS

Fracture risk in childhood is related to volumetric BMD, reflecting an influence of determinants of volumetric BMD such as cortical thickness on skeletal fragility. Although bone size per se was not related to fracture risk, we found that children who fracture tend to have a smaller skeleton relative to their overall body size.

Adipose tissue stimulates bone growth in prepubertal children

CONTEXT

Fat mass represents a positive influence on bone mass in adults, independently of other factors such as lean mass, but whether a similar action occurs in children is unclear.

OBJECTIVE

Our objective was to examine the relationship between fat mass and bone mass in children.

DESIGN AND SETTING

We conducted combined cross-sectional and prospective analyses at university research clinics.

PARTICIPANTS

Participants included children aged 9.9 yr from a large population-based birth cohort in southwest England.

OUTCOMES

Relationships between total body fat mass were measured by dual-energy x-ray absorptiometry at age 9.9 yr, and 1) total-body-less-head bone mass and area at age 9.9 and 2) increase in bone mass and area over the following 2 yr.

RESULTS

There was a strong positive relationship between total body fat mass and total-body-less-head bone mass and area, even after adjustment for height and/or lean mass (P < 0.001). There was a similar positive association between total body fat mass and increase in bone mass and area over the following 2 yr in boys and Tanner stage 1 girls. In contrast, no association was present between fat mass and gain in bone mass and size in Tanner stage 2 girls, whereas a negative association was seen in Tanner stage 3 girls (puberty-fat mass interaction, P < 0.001).

CONCLUSIONS

In prepubertal children, fat mass is a positive independent determinant of bone mass and size and of increases in these parameters over the following 2 yr, suggesting that adipose tissue acts to stimulate bone growth. However, this relationship is attenuated by puberty.

Association between bone density and fractures in children: a systematic review and meta-analysis

OBJECTIVE

The objective of this article was to systematically review all published studies that investigated the association between bone density and fractures in children.

DESIGN

Potentially relevant articles were identified by searching electronic databases. Duplicates were removed, abstracts were inspected, and relevant articles were obtained. Studies were included in the systematic review if participants were <16.0 years old, were healthy, had extractable data on bone mass, and had fractures as the outcome.

RESULTS

Ten case-control studies were identified. No prospective studies were found. There was no evidence of heterogeneity between studies or of funnel-plot asymmetry. Eight of the studies were included in the meta-analysis, because they presented results as means and standard deviations of bone density in cases and controls. The pooled standardized mean difference for bone mass in children with and without fractures, from a fixed-effects model, was -0.32 (95% confidence interval: -0.43 to -0.21).

CONCLUSIONS

Evidence for an association between bone density and fractures in children is limited. The results from this meta-analysis suggest that there is an association between low bone density and fractures in children. Although there was no evidence of heterogeneity or publication bias, this meta-analysis is based on case-control studies that are prone to bias. Large, well-conducted prospective cohort studies are required to confirm the association between bone density and fractures in children.

Social position affects bone mass in childhood through opposing actions on height and weight

We studied relationships between social position of the mother in pregnancy and bone mass of the child at age 9.9 years. The tendency for social position to increase bone area and bone mass through a positive influence on height was opposed by a negative effect of social position on weight and fat mass.

INTRODUCTION

Evidence that social factors influence skeletal growth raises the possibility that bone mass acquisition in childhood is socially determined.

MATERIALS AND METHODS

To clarify the role of social factors in bone mass acquisition in childhood, we studied relationships between these variables in the Avon Longitudinal Study of Parents and Children (ALSPAC). Measures of the mother's social position during pregnancy were linked to DXA results obtained at age 9.9 years in 6,702 children. Linear regression analyses were carried out after adjusting for age and gender. Because social position may affect height and weight of the child, analyses were repeated after adjusting for these additional variables.

RESULTS

Measures of social position in pregnancy were unrelated to total body BMC in analyses adjusted for age and gender alone. However, after adjusting for height, which was positively related to social position, a strong negative association was observed between BMC and housing tenure (p < 0.001), maternal education (p < 0.001), paternal education (p < 0.001), and social class (p < 0.001). Similar results were obtained for bone area. After adjusting for weight as well as height, an association between social position and BMC and bone area was no longer observed. Hence, social position seems to exert opposing height- and weight-dependent effects on BMC and bone area in childhood. In further analyses, we found that adjusting for fat mass of the child led to similar results to those obtained with weight.

CONCLUSIONS

Social position in childhood seems to be positively related to bone mass acquisition in childhood as a consequence of enhanced gain in height (i.e., longitudinal growth). However, this influence is counteracted by the tendency for increased fat deposition in those from a lower social position to increase bone area, presumably reflecting the stimulation of appositional bone growth.

Evaluation of a broadly reactive nucleic acid sequence based amplification assay for the detection of noroviruses in faecal material

A recently described nucleic acid sequence based amplification (NASBA) assay for the detection of genogroup I (GI) and genogroup II (GII) norovirus RNA in faecal samples was evaluated against a reverse transcription polymerase chain reaction (RT-PCR). Both assays were used to screen a panel of 38 faecal samples known to contain 17 different norovirus strains and 131 clinical samples collected from 60 gastroenteritis outbreaks of unknown aetiology. The NASBA assay detected 13 out of the 17 strains of norovirus in the characterised panel, failing to detect a single GII strain and three GI strains. There was 90% agreement between the two assays used to detect norovirus in clinical samples from outbreaks. NASBA detected norovirus RNA in all 64 samples positive by RT-PCR and also detected norovirus RNA in additional 13 samples that were negative by RT-PCR. The sensitivity and specificity of NASBA was 100% and 80%, respectively, compared to RT-PCR results. The norovirus NASBA assay was shown to be highly sensitive and specific, and its ease of use and rapid turnaround time makes it a favourable alternative to RT-PCR for the investigation of norovirus outbreaks.

Development and validation of brief scales to measure collectivism, religiosity, racial pride, and time orientation in urban African American women

This article describes the development and pilot-testing of brief scales to measure four cultural constructs prevalent in urban African American women. Internal consistency and temporal stability were assessed in two convenience samples (n=47 and n=25) of primarily lower-income African American women. All scales performed well: collectivism alpha=.93, r=.85, p<.001); religiosity (alpha=.88, r=.89, p<.001); racial pride (alpha=.84, r=.52, p<.001); present time orientation (alpha=.73, r=.52, p<.01) and future time orientation (alpha=.72, r=.54, p=.07).

Understanding the effects of printed health education materials: which features lead to which outcomes?

Printed health education materials (HEMs) are widely used to increase awareness and knowledge, change attitudes and beliefs, and help individuals adopt and maintain healthy lifestyle behaviors. While much of the contemporary research and development of persuasive communication is based on McGuire's input/output model, to date few studies have compared the impact of a large set of inputs across a comprehensive set of the 12 outputs. We examined the effects of printed HEMs on weight loss on the cognitive, affective, and behavioral responses of 198 overweight adults. Participants were recruited via a newspaper advertisement and were randomly assigned to review one of three HEMs. Participants were interviewed and asked to complete a series of questionnaires both before and after viewing the HEMs. Regression analyses were conducted to identify the input characteristics associated with success at each of the output steps. The results revealed attractiveness, encouragement, level of information, and application to one's life were significantly associated with early steps (attention, liking, and understanding) as well as some of the mediating steps (recalling, keeping, and rereading HEMs). Later steps, such as intention to change behavior and show others, were associated with readiness to change, self-efficacy, and perceived application to one's life. Behavior change was more likely for those who received tailored materials and those who had higher self-efficacy. These results provide useful direction for the use of computers in tailoring the content of HEMs and the development of effective communication of health information on weight loss.

Weight locus of control and weight-related attitudes and behaviors in an overweight population

Rotter's [Psychol. Monogr. 80 (1966)] construct of internal-external control of reinforcement led to the conceptualization of locus of control as a personality construct that can be used to predict behavior. More specific measures of locus of control in particular behavioral domains have followed. In the present study, the Weight Locus of Control Scale (WLOC) was used to predict weight-related attitudes and behaviors of overweight individuals, as well as their responses to health education materials (HEM) on weight loss. The WLOC scores predicted responses to baseline weight-related measures such as etiology of obesity, confidence in weight loss behaviors, and behavioral intention. In addition, WLOC scores predicted participants' reactions to the HEM, as well as the actual number of weight loss ideas from the HEM that the participants tried by the 1-month follow-up assessment. The results are discussed in terms of the validity of the WLOC and implications for future development of effective HEM.

Does locus of control moderate the effects of tailored health education materials?

Research in health communication has shown that individually tailored health education materials are more effective than traditional or generic materials in producing changes in health-related behaviors. However, tailored materials have not been equally effective for all individuals. Because locus of control affects behavioral outcomes in other self-change interventions, its effect on individuals' responses to tailored messages is of particular interest. The present study examined differences in cognitive responses to tailored and non-tailored weight loss materials among 198 overweight individuals. Weight locus of control significantly interacted with study group (who received either tailored or non-tailored materials), suggesting that externals may respond to tailored health education materials with counter-arguments. Implications for the development and application of tailored health communication materials are discussed.

Are tailored health education materials always more effective than non-tailored materials?

While promising, the evidence in support of tailored health communication has not been overwhelming. One explanation is that tailored materials may be far superior to non-tailored materials in some cases, but only slightly better, no different or less effective in others. In this study, 198 overweight adults were randomly assigned to receive either tailored or non-tailored weight loss materials. Participants' cognitive, affective and behavioral responses to the materials were measured at an immediate and 1 month follow-up. Analyses compared those who received tailored materials to those who received non-tailored materials that were--by chance alone--either a good fit, moderate fit or poor fit, based on the match between behavioral characteristics of the participant and content of the non-tailored materials. Findings showed that good-fitting non-tailored materials performed as well or better than tailored materials for several cognitive, affective and behavioral outcomes. However, moderate- and poor-fitting non-tailored materials were consistently inferior to both approaches. The art and science of creating tailored health communication programs is still evolving. Data from this study suggest present approaches to tailoring are more effective than non-tailored materials in most, but not all cases. Specific recommendations are made describing ways to refine tailoring methods to maximize the effectiveness of this approach.

Understanding how people process health information: a comparison of tailored and nontailored weight-loss materials

Health information tailored to meet individuals' unique needs has been shown to be more effective than generic information in promoting risk-reducing behavior changes. To explore mechanisms underlying tailoring's effectiveness, this study randomly assigned 198 overweight adults to receive weight-loss materials that were (a) tailored to the individual, (b) in an American Heart Association (AHA) brochure, or (c) AHA-content formatted to look like tailored materials. Participants who received tailored materials had more positive thoughts about the materials, positive personal connections to the materials, positive self-assessment thoughts, and positive thoughts indicating behavioral intention than those who received either of the untailored materials. The tailoring of health information can significantly improve the chances the information will be thoughtfully considered and can stimulate prebehavioral changes such as self-assessment and intention.

Understanding how people process health information: a comparison of tailored and nontailored weight-loss materials

Health information tailored to meet individuals' unique needs has been shown to be more effective than generic information in promoting risk-reducing behavior changes. To explore mechanisms underlying tailoring's effectiveness, this study randomly assigned 198 overweight adults to receive weight-loss materials that were (a) tailored to the individual, (b) in an American Heart Association (AHA) brochure, or (c) AHA-content formatted to look like tailored materials. Participants who received tailored materials had more positive thoughts about the materials, positive personal connections to the materials, positive self-assessment thoughts, and positive thoughts indicating behavioral intention than those who received either of the untailored materials. The tailoring of health information can significantly improve the chances the information will be thoughtfully considered and can stimulate prebehavioral changes such as self-assessment and intention.

Investigation of measures to reduce interfering abdominal activity on rest myocardial images with Tc-99m sestamibi

With the new myocardial agent Tc-99m sestamibi, relatively high abdominal uptake represents a major limiting factor. The effect of a standard feeding (commercial milkshake taken immediately after injection), and posture (standing versus sitting for 10 minutes postinjection) on the resting biodistribution of sestamibi was investigated in patients receiving 3 to 5 MBq/kg injections as part of rest-stress tomography. Ancillary anterior 1-minute images of heart and abdomen were obtained at 15 minutes postinjection and 90 to 140 minutes postinjection in 32 patients, randomized to feeding and postural treatments. Feeding decreased the activity in the gallbladder at both 15 and 110 minutes, but had no effect on liver parenchyma; activity in a background rectangle immediately beneath the heart was decreased by feeding only on the 15-minute images. An effect of posture was not apparent. Further study of the acute effects of a milkshake in eight patients showed a prompt reduction of 26% in a subdiaphragmatic background rectangle, but a more gradual decline in gallbladder counts. Thus, feeding of lipid after injection is not an essential component of sestamibi imaging protocols; oral administration of fluid immediately before imaging may help reduce interfering gastric activity.

d(TG)n.d(CA)n sequences upstream of the rat prolactin gene form Z-DNA and inhibit gene transcription

Two alternating purine-pyrimidine sequences of the d(TG)n.d(CA)n-type (170bp and 60 bp in length) lie upstream of the rat prolactin (rPRL) gene. Conformational studies of plasmids containing these sequences indicate that both form left-handed (Z) DNA, with transitions initiating at superhelical densities of -0.041 and -0.044 respectively. These alternating purine-pyrimidine (APP) sequences are hypersensitive to cleavage with S1 nuclease both at the boundaries and within these APP repeats, where there is a loss in APP alternation. We have investigated the function of one of these Z-DNA sequences in the regulation of rPRL transcription, by linking regions of the 5' flanking sequence of the rPRL gene to a reporter gene encoding chloramphenicol acetyltransferase (CAT), and transferring these plasmids into GH3 pituitary tumour cell lines. The major conclusion from these studies is that the 170bp repeat exerts a negative effect on the transcription of the rPRL gene, and also down-regulates the expression of the fusion gene pRSVcat when cloned 50bp upstream of the Rous sarcoma virus promoter. However, despite its proximity to an estrogen response element in prolactin, this sequence does not affect the responsiveness of the rPRL gene to estrogen.

The comparability of two commonly used carbon monoxide analysis systems: a technical note

Carbon monoxide (CO) in expired breath is a common strategy for verifying smoking abstinence. The purpose of this investigation was to determine the comparability of two carbon monoxide (CO) analyzers: the commonly used Ecolyzer Series 2000 analyzer versus the new, highly portable, and less expensive Ecolyzer Model 210. Fifty-eight CO readings were obtained from 29 subjects (17 smokers, 12 nonsmokers) and analyzed on both systems simultaneously. Results indicated that the analyzers yielded highly comparable values for both smokers and nonsmokers. Moreover, the correlation between the two units' readings was very high (r = .92, p less than .001). There was, however, a significant analyzer by sex interaction with the Series 2000 analyzer yielding higher values for males. Overall, it was concluded that the Series 210 analyzer is a highly accurate and cost-effective instrument.

Insulin therapy in patients with poorly controlled non-insulin dependent diabetes mellitus

In spite of maximal doses of sulphonylurea agents, patients with poorly controlled non-insulin dependent diabetes (NIDDM) often do not have improved metabolic control after the introduction of insulin therapy. We have assessed 22 patients with NIDDM who commenced insulin therapy in order to identify those characteristics which were associated with an improvement in glycaemic control. Twelve months after the commencement of insulin therapy, 14 (64%) patients showed a decrease in glycosylated haemoglobin (HbA1) levels; 12 of the 14 (55%) patients had achieved HbA1 levels that were considered to reflect acceptable glycaemic control (HbA1 less than or equal to 11%; reference range, 6%-9%). The HbA1 levels in the other patients either remained unchanged or had increased (one subject). When the subjects who had achieved good glycaemic control with insulin therapy were compared with the remainder of the group, a failure to improve with insulin therapy was associated with a longer duration of diabetes, greater obesity and higher levels of cholesterol and triglycerides before the commencement of insulin therapy. Greater obesity and high levels of circulating lipids were found by means of multiple linear regression analysis to correlate independently with a poor response to insulin therapy. We conclude that standard insulin therapy can improve the majority of patients with poorly controlled NIDDM. However, there is a substantial number of patients, who tend to be obese and have high levels of circulating lipids, whose condition does not improve with insulin therapy, or who require more aggressive dosage increases than are used as a routine.

Outpatient initiation of insulin therapy in patients with diabetes mellitus

Before insulin therapy is begun, patients with diabetes are often admitted to hospital. In a retrospective study we have reviewed the initiation of insulin therapy in 54 unselected outpatients (12 of whom were insulin-dependent), when the initial stabilization of therapy was performed predominantly by nurse educators. Most patients found the procedure satisfactory; only one subject indicated dissatisfaction with the regimen and only two indicated that they would have preferred admission to hospital. No patient experienced an acute hypoglycaemic or hyperglycaemic problem that required admission to hospital nor was emergency intervention required during the 12 months that followed the initial stabilization period of insulin therapy. Metabolic control, as measured by glycosylated haemoglobin levels, improved in the majority of both insulin-dependent and non-insulin-dependent patients after 12 months of insulin therapy. A retrospective cost analysis that compared the cost of the outpatient procedure with the cost (hospital-bed costs only) of initiating insulin therapy in a similar group of patients who were admitted to hospital, indicated a saving of $1857 for each outpatient. We conclude that the outpatient initiation of insulin therapy is feasible where the facilities for education about diabetes exist, that it is safe, achieves satisfactory metabolic control, is acceptable to most patients, and offers a considerable saving in costs.

Insulin dosage reduction. Evaluation of an education-stabilization programme for patients with insulin-dependent diabetes

A retrospective survey was conducted of 52 consecutive subjects with insulin-treated diabetes who were attending an education-stabilization programme. Eleven subjects (21%) achieved more than a 20% reduction in daily insulin dosage six months after completion of the programme. Compared with the remainder of the group, these subjects had a significantly earlier age of onset, higher initial insulin dosage (mean, 61 units/day, compared with 39 units/day), higher initial insulin carbohydrate and fat consumption, but similar initial glycosylated haemoglobin levels. These results suggest that overinsulinization is a relatively frequent occurrence and should be particularly considered in younger patients who are receiving relatively large doses of insulin.

Gene amplification in methotrexate-resistant mouse cells. V. Intact amplified units can be transferred to and amplified in methotrexate-sensitive mouse L cells

Wild-type mouse LtAp20 cells were treated with calcium phosphate-precipitated DNA or chromosomes from two highly Methotrexate (MTX)-resistant mouse lymphoma cell lines--EL4/8 and EL4/11. Transfections with purified MTX-resistant DNA produced colonies of LtAp20 cells resistant to 3 X 10(-8) M MTX, at about eight times the frequency with which resistant colonies arose in control transfections. DNA transfectants contained multiple copies of the dihydrofolate reductase (dhfr) gene, but other sequences characteristic of the donor DNA could not be detected. Transfections using isolated chromosomes were twice as efficient as those using purified DNA. Unlike DNA transfectants, over 90% of all chromosome transfectants took up large stretches of donor DNA intact and contained DNA sequences characteristic of donor DNA. Of chromosome transfectants selected for resistance to high levels of MTX (1 mM), 70% amplified a unit of DNA which was indistinguishable from that present in the donor cell. The results showed that large fragments of chromosomes (as opposed to purified DNA) can be taken up to recipient cells without detectable alteration to the fine structure of the DNA they contain. The results also support the notion that all amplified units within a MTX-resistant cell have the same overall complex DNA structure.

Association of an endophytic fungus with fescue toxicity in steers fed Kentucky 31 tall fescue seed or hay

Previous research has implicated an endophytic fungus as being associated with fescue toxicity (summer syndrome) in cattle grazing Kentucky 31 tall fescue (Festuca arundinacea Schreb.) pastures. Hay and seed were harvested from Kentucky 31 pastures known to be either fungus-free or heavily infested with an endophytic fungus identified as Acremonium coenophialum Morgan-Jones and Gams. Four diets containing either 60% fungus-free seed, 60% fungus-infested seed, 85% fungus-free hay or 85% fungus-infested hay were group-fed to three steers each (avg wt 239 kg) in a 53-d feeding trial. Presence of the fungus reduced (P less than .05) daily gains (kg/d) in steers fed either the seed diets (.96 vs .20) or the hay diets (.66 vs .28). Feed intake was depressed 36% for the seed diets and 8% for the hay diets when the fungus was present. Rectal temperatures were elevated .6 C (P less than .05) for both groups receiving diets containing the fungus, but respiration rate was elevated only in the fungus-infested seed group. In vitro dry matter disappearance was not decreased by presence of the fungus. Steers receiving fungus from either seed or hay were nervous and highly excitable, which resulted in large variations in plasma epinephrine and norepinephrine concentrations. The results of this experiment further implicate an endophytic fungus as being associated with fescue toxicity.

Data integrity in a general practice computer system (CLINICS)

The accuracy of computer held medical information may be of critical importance in patient care, therefore it is important not only to know the error rate in the stored data but also to know the effectiveness of error checking and detection programmes. This paper reports on the errors which were detected in the University of Southampton Primary Medical Care computer system (CLINICS) by checking the consistency between stored data and incoming data. Seven per cent of incoming data had important errors of kinds not normally detected by many medical record systems. The majority were traced either to the registration of new patients or to the doctors failing to pay adequate attention to detail in their record keeping (or to their legibility). They have been subsequently corrected, and it is calculated that the stored data contains less than 1% errors. We suggest ways of improving this; and conclude that certain items are essential to general practice information systems.

A new design concept for an audio dosimeter

A design concept for a new audio dosimeter is presented which can be used to evaluate employee exposure to both continuous and impulsive noise more accurately. Unlike existing dosimeters, the instrument is capable of eliminating the influence of impulsive sounds upon the employee exposure or "dose." The concept relies upon an interpretation of the intent of existing and proposed U.S. Department of Labor regulations with regard to the evaluation of continuous and impulsive sounds. This paper presents the rationale for the design concept, the block diagram of the microprocessor-based instrument, and a summary of its intended operation.