Species-specific behaviours in amphipods highlight the need for understanding baseline behaviours in ecotoxicology

Behavioural studies in ecotoxicology are increasing with techniques and endpoints used in pharmacology being translated to other vertebrate and invertebrate species. Despite this, data on the baseline behaviours of model organisms, and inter-species variability in behaviour are currently under-studied. This study assessed a range of behaviours associated with anxiety including swimming speed, phototaxis and thigmotaxis in a marine and freshwater amphipod (Echinogammarus marinus and Gammarus pulex). Differences in sensitivity to these assays were observed between species with E. marinus showing a greater sensitivity to the phototaxis assay than G. pulex, while in thigmotaxis assays G. pulex appeared better suited than E. marinus for measuring differences in the use of central zones. Significant inter-species differences were also observed in swimming patterns when breaking the data into ten second time bins but not when data was broken into two-minute time bins. The results of this study provide evidence of phototactic and thigmotactic behaviours in two model crustacean species with potential for use in behavioural ecotoxicology. Inter-species variability in sensitivity to behavioural assays highlights the importance of systematic assessment of baseline responses for all model species used in behavioural studies. Careful analysis of data is also required when performing behavioural studies so as not to lose sensitivity in your data.

Shape and size of the arenas affect amphipod behaviours: implications for ecotoxicology

The use of behaviour in ecotoxicology is expanding, however the lack of standardisation and validation of these assays currently presents a major drawback in moving forward in the development of behavioural assays. Furthermore, there is a current paucity of control data on test species, particularly invertebrate models. In this study we assessed a range of behaviours associated with spatial distribution and locomotion in relation to arena size and shape in two species of amphipod crustacean (Echinogammarus marinus and Gammarus pulex). Arena shape had significant effects on almost all behavioural parameters analysed. Increasing arena size resulted in an increased mean velocity and activity plus increased proportional use of the central zones. These results indicate that 'ceiling effects' may occur in some ecotoxicological studies resulting in potentially 'false' negative effects if careful consideration is not paid to experimental design. Differences in behaviours were observed between the two species of amphipod. For example, G. pulex spend approximately five times (∼20%) more of the available time crossing the central zones of the arenas compared to E. marinus (∼4%) which could have implications on assessing anxiolytic behaviours. The results of this study highlight several behaviours with potential for use in behavioural ecotoxicology with crustaceans but also underscore the need for careful consideration when designing these behavioural assays.

Qualitative study of clinic staff members' experiences using an immunization registry

OBJECTIVES

To examine individual clinic staff members' experiences with using an immunization registry and to compare staff members' perceptions of immunization registries across different provider sites.

DESIGN

Cross-sectional survey using in-depth interviews and direct observation.

SETTINGS

The pediatric department of an urban community health center and 2 urban hospital-based pediatric primary care clinics.

PARTICIPANTS

Twenty-five subjects were recruited using maximum variation sampling at each site. The subjects included clerks, clinic assistants, licensed practical nurses, a nurse practitioner, and registered nurses.

MAIN OUTCOME MEASURES

Clinic staff members' perceptions of an immunization registry and frequency of registry use.

RESULTS

Differences were observed in subjects' perceptions of an immunization registry across provider sites. Although most subjects had positive attitudes toward the registry, they did not necessarily believe that the registry decreased their workload. The ability to access immunization registry data and actual use of the registry seem to be related to training of clinic personnel, location of the registry terminal, and helpfulness and availability of registry staff.

CONCLUSION

Obtaining the opinions of immunization registry users is an important strategy to evaluate the usefulness of a registry in a site and target possible areas for improvement.

The cost to providers of participating in an immunization registry

INTRODUCTION

The medical and public health communities advocate immunization registries as one tool to achieve national immunization goals. Although substantial resources have been expended to establish registries across the nation, minimal research has been conducted to evaluate provider participation costs.

METHODS

The objective of this study was to identify the direct costs to participate in an immunization registry. To estimate labor and equipment costs, we conducted interviews and direct observation at four sites that were participating in one of two immunization registries. We calculated mean data-entry times from direct observation of clinic personnel.

RESULTS

The annual cost of participating in a registry varied extremely, ranging from $6083 to $24,246, with the annual cost per patient ranging from $0.65 to $7. 74. Annual per-patient costs were lowest in the site that used an automated data-entry interface. Of the sites requiring a separate data-entry step, costs were lowest for the site participating in the registry that provided more intensive training and had a higher proportion of the target population entered into the registry.

CONCLUSIONS

Ease of registry interface, data-entry times, and target population coverage affect provider participation costs. Designing the registry to accept electronic transfers of records and to avoid duplicative data-entry tasks may decrease provider costs.

Measuring immunization registry costs: promises and pitfalls

INTRODUCTION

The medical and public health communities advocate the use of immunization registries as one tool to achieve national goals for immunization. Despite the considerable investment of resources into registry development, little information is available about the costs of developing or maintaining a registry.

METHODS

The objective of this study was to measure the direct costs of maintaining one immunization registry. Cost and resource-use data were collected by interviewing registry personnel and staff at participating pediatric practices, collecting available financial records, and direct observation.

RESULTS

The estimated direct cost for maintaining the registry during the 3 calendar years 1995 through 1997 was $439,232. In 1997, this represented an annual cost of $5.26 per child immunized whose record was entered into the registry. In all years, personnel expenses represented at least three fourths of the total costs, with the majority of administrative effort donated. Yearly costs increased over time largely because of growing administrative personnel requirements as the registry became fully operational.

CONCLUSION

Considerable resources are required to establish and maintain immunization registries. Because personnel costs, particularly nontechnical personnel, represent a large portion of total registry costs, it is important to accurately account for donated effort. Recommendations for future registry cost studies include prospective data collection and focusing upon the costs of providing specific outreach or surveillance functions rather than overall registry costs. In addition, registry effectiveness evaluations are needed to translate registry costs into cost-effectiveness ratios.

The effect of primary care gatekeepers on the management of patients with chest pain

OBJECTIVE

To determine whether patients with chest pain referred to a cardiologist from a gatekeeper managed care organization differ from those referred from an open-access managed care organization.

STUDY DESIGN

Retrospective study using clinical and claims data from a cardiac network database.

PATIENTS AND METHODS

We reviewed data from 1414 patients with chest pain or angina who were referred to a cardiologist between January 1, 1995, and June 30, 1996. We examined baseline clinical characteristics and subsequent physician practice patterns for these patients, who were referred from either a primary care gatekeeper model (n = 490) or an open-access model (n = 924).

RESULTS

Although twice as many open-access patients were referred to a cardiologist, there were no differences in patient demographics or clinical characteristics at the time of referral. Cardiologists ordered similar diagnostic tests for patients from both types of managed care plans, and gatekeeper patients did not have a higher rate of abnormal tests. Rates of cardiac catheterization, coronary angioplasty, myocardial infarction, and hospitalization were similar in both groups. A significantly higher percentage of gatekeeper patients received a cardiac catheterization on the day of referral (7% versus 1%; P = .05). Open-access patients were significantly more likely to continue to be seen by a cardiologist (44% versus 28%; P < .01). Cardiology professional charges per patient were lower among gatekeeper patients ($972 +/- 1398 versus $1187 +/- 1897; P = .06), and total cardiology professional charges were significantly lower for the gatekeeper group because of the smaller number of patients seen.

CONCLUSIONS

The type of cardiology services provided to patients with chest pain was not affected by the primary care administrative structure of the managed care organization, but the higher volume of patient referrals from the open-access plan may be an important consideration for cardiology practices participating in capitated contracts. The lower volume of referrals and coordination of care suggest potential cost advantages for the gatekeeper model.

Molecular cloning of mouse glycolate oxidase. High evolutionary conservation and presence of an iron-responsive element-like sequence in the mRNA

Iron regulatory proteins (IRPs) control the synthesis of several proteins in iron metabolism by binding to iron-responsive elements (IREs), a hairpin structure in the untranslated region (UTR) of corresponding mRNAs. Binding of IRPs to IREs in the 5' UTR inhibits translation of ferritin heavy and light chain, erythroid aminolevulinic acid synthase, mitochondrial aconitase, and Drosophila succinate dehydrogenase b, whereas IRP binding to IREs in the 3' UTR of transferrin receptor mRNA prolongs mRNA half-life. To identify new targets of IRPs, we devised a method to enrich IRE-containing mRNAs by using recombinant IRP-1 as an affinity matrix. A cDNA library established from enriched mRNA was screened by an RNA-protein band shift assay. This revealed a novel IRE-like sequence in the 3' UTR of a liver-specific mouse mRNA. The newly identified cDNA codes for a protein with high homology to plant glycolate oxidase (GOX). Recombinant protein expressed in bacteria displayed enzymatic GOX activity. Therefore, this cDNA represents the first vertebrate GOX homologue. The IRE-like sequence in mouse GOX exhibited strong binding to IRPs at room temperature. However, it differs from functional IREs by a mismatch in the middle of its upper stem and did not confer iron-dependent regulation in cells.

Dissemination of clinical results. Mastectomy versus lumpectomy and radiation therapy

OBJECTIVES

This study is an assessment of the extent to which clinical findings concerning mastectomy versus lumpectomy with radiation treatment have been disseminated in practice over time.

METHODS

The authors examined the use of breast-conserving surgery followed by radiation therapy as an alternative treatment to mastectomy for early-stage breast cancer by analyzing 5 years (1986-1990) of inpatient and outpatient claims data from four insurers: Medicare, Medicaid, Blue Cross of Western Pennsylvania, and Pennsylvania Blue Shield. The 9,288 women who were eligible for either a lumpectomy or mastectomy during the study period represented approximately 90% of south western Pennsylvania's adult female population. Given the efficacy of both procedures, the authors expected a trend toward more BCS.

RESULTS

By 1990, the use of lumpectomy increased significantly to 42.4% from 35.2%. The choice of lumpectomy was associated with younger women, private health insurance, absence of axillary node metastases, and treatment in urban hospitals. The authors also found, however, that only 45.3% of women with Medicaid coverage who had a lumpectomy during the study period received the requisite follow-up radiation therapy, compared with 77.5% of private insurance subscribers and 88.1% of Medicare beneficiaries. This finding is troubling even though there was substantially more compliance in the later years of the study, with 60.0% of eligible Medicaid beneficiaries receiving follow-up radiation therapy in 1990.

CONCLUSIONS

This research illustrates the usefulness of administrative claims data in describing trends and practice patterns as well as the need for a different type of research to discover the reasons for the lack of compliance with treatment protocols by women or physicians.

Effect of regular physical training on age-associated alteration of body composition in men

Body composition changes with increasing age in men, in that lean body mass decreases whereas fat mass increases. Whether this altered body composition is related to decreasing physical activity or to the known age-associated decrease in growth hormone secretion is uncertain. To address this question, three groups of healthy men (n = 14 in each group), matched for weight, height and body mass index, were investigated using dual-energy X-ray absorptiometry, indirect calorimetry and estimate of daily growth hormone secretion [i.e. plasma insulin-like growth factor I (IGF-I-) levels]. Group 1 comprised young untrained subjects aged 31.0 +/- 2.1 years (mean +/- SEM) taking no regular physical exercise; group 2 consisted of old untrained men aged 68.6 +/- 1.2 years; and group 3 consisted of healthy old men aged 67.4 +/- 1.2 years undergoing regular physical training for more than 10 years with a training distance of at least 30 km per week. Subjects in group 3 had for the past three years taken part in the 'Grand Prix of Berne', a 16.5-km race run at a speed of 4.7 +/- 0.6 min km-1 (most recent race). Fat mass was more than 4 kg higher in old untrained men (P < 0.01, ANOVA) than in the other groups (young untrained men, 12.0 +/- 0.9 kg; old untrained men, 16.1 +/- 1.0 kg; old trained men, 11.0 +/- 0.8 kg), whereas body fat distribution (i.e. the ratio of upper to lower body fat mass) was similar between the three groups. The lean mass of old untrained men was more than 3.5 kg lower (P < 0.02, ANOVA) than in the other two groups (young untrained men, 56.4 +/- 1.0 kg; old untrained men, 52.4 +/- 1.0 kg; old trained men, 56.0 +/- 1.0 kg), mostly because of a loss of skeletal muscle mass in the arms and legs (young untrained men, 24.0 +/- 0.5 kg; old untrained men 20.8 +/- 0.5 kg; old trained men, 23.6 +/- 0.7 kg; P < 0.01, ANOVA). Resting metabolic rate per kilogram lean mass decreased with increasing age independently of physical activity (r = -0.42, P < 0.005). Fuel metabolism was determined by indirect calorimetry at rest. Protein oxidation was similar in the three groups. Old untrained men had higher (P < 0.001) carbohydrate oxidation (young untrained men, 13.2 +/- 1.0 kcal kg-1 lean mass; old untrained men, 15.2 +/- 1.3 kcal Kg-1; old trained men, 7.8 +/- 0.8 kcal kg-1), but lower (P < 0.05, ANOVA) fat oxidation (young untrained men, 10.1 +/- 1.2 kcal kg-1 lean mass; old untrained men, 6.5 +/- 1.0 kcal kg-1; old trained men, 13.7 +/- 1.0 kcal kg-1) than the other two groups. Mean plasma IGF-I level in old trained men was higher than in old untrained men (P < 0.05), but was still lower than that observed in young untrained men (P < 0.005) (young untrained men, 236 +/- 24 ng mL-1; old untrained men, 119 +/- 13 ng mL-1; old trained men, 166 +/- 14 ng mL-1). In summary, regular physical training in older men seems to prevent the changes in body composition and fuel metabolism normally associated with ageing. Whether regular physical training in formerly untrained old subjects would result in similar changes awaits further study.

Succinate dehydrogenase b mRNA of Drosophila melanogaster has a functional iron-responsive element in its 5'-untranslated region

Iron-responsive elements (IREs) are cis-acting mRNA stem-loop structures that specifically bind cytoplasmic iron regulatory proteins (IRPs). IRP-IRE interactions mediate the coordinate post-transcriptional regulation of key proteins in iron metabolism, such as ferritin, transferrin receptor, and erythroid 5-aminolevulinic acid synthase. Depending on whether the IRE is located in the 5'- or 3'-untranslated region (UTR), binding of IRP will inhibit mRNA translation or degradation, respectively. Here we describe a new IRE in the 5'-UTR of succinate dehydrogenase subunit b (SDHb) mRNA of Drosophila melanogaster. The SDHb IRE binds in vitro to vertebrate and insect IRPs with a high affinity equal to that of human ferritin H chain IRE. Under conditions of iron deprivation, SDHb mRNA of Drosophila SL-2 cells shifts to a non-polysome-bound pool. Moreover, translation of a human growth hormone mRNA with the SDHb IRE in its 5'-UTR is iron-dependent in stably transfected L cells. We conclude that the SDHb IRE mediates translational inhibition both in insect and vertebrate cells. This constitutes the first identification of a functional IRE in insects. Furthermore, Drosophila SDHb represents the second example, after porcine mitochondrial aconitase, of an enzyme of the citric acid cycle whose mRNA possesses all necessary features for translational regulation by cellular iron levels.