Commercial weight management programmes for patients living with overweight or obesity prior to elective orthopaedic surgery: an evidence review

BACKGROUND

Increased body mass index is associated with increased operative risk during elective joint replacement surgery. Commercial weight management programmes are designed to achieve weight loss. It is not known whether commercial weight management programmes are effective at achieving weight loss in patients awaiting planned hip or knee replacement surgery, or whether achieving significant planned weight loss prior to surgery is associated with changes in surgical outcome.

METHODS

A systematic literature search of seven databases was conducted. Reference lists and grey literature were searched, including commercial weight management programme and medical association websites. Four relevant primary interventional studies were identified.

RESULTS

There is weak, low-quality evidence from four small studies, of which three demonstrated that commercial weight management programmes initiated between 3 and 6 months prior to elective joint replacement surgery are associated with a statistically significant weight loss and body mass index reduction. There is a weak evidence from two studies that peri- and post-operative complications are similar between control and commercial weight management programme groups.

CONCLUSION

There is a paucity of studies investigating commercial weight management programmes aiming to reduce weight in patients living with overweight or obesity awaiting total joint replacement. Further, high-quality research is urgently needed.

Correction to: Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women

The original version of this article, published on 14 December 2018, unfortunately contained a mistake.

Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women

In a population-based sample of British women aged over 70 years old, lean mass and peak lower limb muscle force were both independently associated with hip strength and fracture risk indices, thereby suggesting a potential benefit of promoting leg muscle strengthening exercise for the prevention of hip fractures in postmenopausal women.

INTRODUCTION

To investigate cross-sectional associations of lean mass and physical performance, including lower limb muscle function, with hip strength, geometry and fracture risk indices (FRIs) in postmenopausal women.

METHODS

Data were from the Cohort of Skeletal Health in Bristol and Avon. Total hip (TH) and femoral neck (FN) bone mineral density (BMD), hip geometry and total body lean mass (TBLM) were assessed by dual x-ray absorptiometry (DXA). Finite element analysis of hip DXA was used to derive FN, intertrochanteric and subtrochanteric FRIs. Grip strength, gait speed and chair rise time were measured objectively. Lower limb peak muscle force and muscle power were assessed by jumping mechanography.

RESULTS

In total, 241 women were included (age = 76.4; SD = 2.6 years). After adjustment for age, height, weight/fat mass and comorbidities, TBLM was positively associated with hip BMD (β_{TH BMD} = 0.36, P ≤ 0.001; β_{FN BMD} = 0.26, P = 0.01) and cross-section moment of inertia (0.24, P ≤ 0.001) and inversely associated with FN FRI (- 0.21, P = 0.03) and intertrochanteric FRI (- 0.11, P = 0.05) (estimates represent SD difference in bone measures per SD difference in TBLM). Lower limb peak muscle force was positively associated with hip BMD (β_{TH BMD} = 0.28, P ≤ 0.001; β_{FN BMD} = 0.23, P = 0.008) and inversely associated with FN FRI (- 0.17, P = 0.04) and subtrochanteric FRI (- 0.18, P = 0.04). Associations of grip strength, gait speed, chair rise time and peak muscle power with hip parameters were close to the null.

CONCLUSIONS

Lean mass and lower limb peak muscle force were associated with hip BMD and geometrical FRIs in postmenopausal women. Leg muscle strengthening exercises may therefore help prevent hip fractures in older women.

Impact of mild and moderate/severe vertebral fractures on physical activity: a prospective study of older women in the UK

Little is known about the long-term impact of vertebral fractures on physical activity. There is also uncertainty over the clinical significance of mild vertebral fracture. We showed that women with moderate/severe but not mild vertebral fracture do less walking duration and housework than those without fracture after 5.4 years of follow-up.

INTRODUCTION

Little is known about the long-term impact of vertebral fractures on physical activities. There is also uncertainty over the clinical significance of mild fracture. Therefore, the aim of this study was to evaluate the prospective association between vertebral fracture and future physical activity.

METHODS

This is a 5-year prospective study of a mixed community and secondary care cohort of women aged > 50 from the UK. Vertebral fractures were identified at baseline on radiographs or DXA-based Vertebral Fracture Assessment by a Quantitative Morphometric approach and defined as moderate/severe (≥ 25% height decrease) or mild (20-24.9% height decrease). Physical activity data were collected 5.4 years later by self-completion questionnaires. Multivariable logistic regression was used to determine the association between presence of fracture and various physical activities while adjusting for potential confounders.

RESULTS

Two hundred eighty-six women without, 58 with mild, and 69 with moderate/severe fracture were recruited. Those with mild and moderate/severe fracture were older than women without fracture and had more concomitant diseases at baseline. At 5.4 years follow-up, women with moderate/severe fracture self-reported shorter walking duration compared to those without fracture, even after adjusting for potential confounders (OR 2.96, 95%CI 1.11-7.88, P = 0.030). No independent association was seen between the presence of mild fractures and reduced physical activity at follow-up.

CONCLUSION

This is the first study of older women from the UK that explored the prospective association between vertebral fracture and physical activity duration. Moderate/severe fractures were associated with reduced walking duration. Mild fractures had no impact on future physical ability.

An observational cohort study to produce and evaluate an improved tool to screen older women with back pain for osteoporotic vertebral fractures (Vfrac): study protocol

The aim of this study is to produce an easy to use checklist for general practitioners to complete whenever a woman aged over 65 years with back pain seeks healthcare. This checklist will produce a binary output to determine if the patient should have a radiograph to diagnose vertebral fracture.

PURPOSE

People with osteoporotic vertebral fractures are important to be identified as they are at relatively high risk of further fractures. Despite this, less than a third of people with osteoporotic vertebral fractures come to clinical attention due to various reasons including lack of clear triggers to identify who should have diagnostic spinal radiographs. This study aims to produce and evaluate a novel screening tool (Vfrac) for use in older women presenting with back pain in primary care based on clinical triggers and predictors identified previously. This tool will generate a binary output to determine if a radiograph is required.

METHODS

The Vfrac study is a two-site, pragmatic, observational cohort study recruiting 1633 women aged over 65 years with self-reported back pain. Participants will be recruited from primary care in two sites. The Vfrac study will use data from two self-completed questionnaires, a simple physical examination, a lateral thoracic and lateral lumbar radiograph and information contained in medical records.

RESULTS

The primary objective is to develop an easy-to-use clinical screening tool for identifying older women who are likely to have vertebral fractures.

CONCLUSIONS

This article describes the protocol of the Vfrac study; ISRCTN16550671.

Correction to: Using self-reports of pain and other variables to distinguish between older women with back pain due to vertebral fractures and those with back pain due to degenerative changes

This article was originally published under a CC BY-NC-ND 4.0 license, but has now been made available under a CC BY 4.0 license. The PDF and HTML versions of the paper have been modified accordingly.

Self-reported everyday physical activities in older people with osteoporotic vertebral fractures: a systematic review and meta-analysis

Previous work has shown that patients with vertebral fractures do less physical activity. However, the association between vertebral fracture and different components of physical activity is unclear. Our results suggest that vertebral fracture (VF) is associated with a reduction in activities involving bending, ambulation, and daily living, regardless of age.

INTRODUCTION

The aim of this study was to determine whether osteoporotic VF is associated with reduced self-reported everyday routine physical activity and/or ability (PAA).

METHODS

A comprehensive search was undertaken using the databases of PubMed, Embase, Medline, Web of Science, and the "grey" literature from 1950 to the end of July 2016. Standardised search terms for VF and PAAs were used. Four categories of PAA were included: (1) bending ability, (2) ambulatory activities, (3) reaching arms above shoulder level, and (4) activities of daily living (ADLs). Strict inclusion and exclusion criteria were used, and only studies that adjusted for age were included. For the meta-analysis, pooled OR and 95% confidence interval (CI) were calculated using a random-effects model.

RESULTS

Eleven studies in total were identified which had investigated the associations between the prevalent VF and the selected PAAs and expressed these as ORs or RR. Women (six studies) with VF had a 64% increase in difficulty forward bending compared to those without VF. Women (nine studies) with VF had a 27% increase in difficulty doing ambulatory activities, while no association was observed for men (four studies). Women also have 73% (five studies), 127% (three studies), and 100% (four studies) increase in difficulty reaching arms above shoulder, shopping, and preparing meals, respectively.

CONCLUSION

Studies consistently show women with VF have reduced everyday activities, while much less research has been carried out in men. This information may be useful when designing interventions to improve physical function in people with osteoporotic VFs.

Test-retest reliability and smallest detectable change of the Bristol Impact of Hypermobility (BIoH) questionnaire

OBJECTIVE

The Bristol Impact of Hypermobility (BIoH) questionnaire is a patient-reported outcome measure developed in conjunction with adults with Joint Hypermobility Syndrome (JHS). It has demonstrated strong concurrent validity with the Short Form-36 (SF-36) physical component score but other psychometric properties have yet to be established. This study aimed to determine its test-retest reliability and smallest detectable change (SDC).

DESIGN

A test-retest reliability study.

SETTING

Participants were recruited from the Hypermobility Syndromes Association, a patient organisation in the United Kingdom.

PATIENTS

Recruitment packs were sent to 1080 adults who had given permission to be contacted about research.

MAIN OUTCOME MEASURES

BIoH and SF-36 questionnaires were administered at baseline and repeated two weeks later. An 11-point global rating of change scale (-5 to +5) was also administered at two weeks. Test-retest analysis and calculation of the SDC was conducted on 'stable' patients (defined as global rating of change -1 to +1).

RESULTS

462 responses were received. 233 patients reported a 'stable' condition and were included in analysis (95% women; mean (SD) age 44.5 (13.9) years; BIoH score 223.6 (54.0)). The BIoH questionnaire demonstrated excellent test-retest reliability (ICC 0.923, 95% CI 0.900-0.940). The SDC was 42 points (equivalent to 19% of the mean baseline score). The SF-36 physical and mental component scores demonstrated poorer test-retest reliability and larger SDCs (as a proportion of the mean baseline scores).

CONCLUSION

The results provide further evidence of the potential of the BIoH questionnaire to underpin research and clinical practice for people with JHS.

Habitual levels of higher, but not medium or low, impact physical activity are positively related to lower limb bone strength in older women: findings from a population-based study using accelerometers to classify impact magnitude

This study assessed the effect of accelerometry-measured higher impacts resulting from habitual weight-bearing activity on lower limb bone strength in older women. Despite higher impacts being experienced rarely in this population-based cohort, positive associations were observed between higher vertical impacts and lower limb bone size and strength.

INTRODUCTION

We investigated whether the benefit of habitual weight-bearing physical activity (PA) for lower limb bone strength in older women is explained by exposure to higher impacts, as previously suggested by observations in younger individuals.

METHODS

Four hundred and eight women from the Cohort for Skeletal Health in Bristol and Avon (COSHIBA), mean 76.8 years, wore tri-axial accelerometers at the waist for a mean of 5.4 days. Y-axis peaks were categorised, using previously identified cutoffs, as low (0.5-1.0 g), medium (1.0-1.5 g), and higher (≥1.5 g) impacts. Mid and distal peripheral quantitative computed tomography scans of the tibia and radius were performed, as were hip and lumbar spine Dual X-ray Absorptiometry (DXA) scans. Regressions between (log transformed) number of low, medium and high impacts, and bone outcomes were adjusted for artefact error grade, age, height, fat and lean mass and impacts in other bands.

RESULTS

Eight thousand eight hundred and nine (4047, 16,882) low impacts were observed during the measurement week, 345 (99, 764) medium impacts and 42 (17, 106) higher impacts (median with 25th and 75th quartiles). Higher vertical impacts were positively associated with lower limb bone strength as reflected by cross-sectional moment of inertia (CSMI) of the tibia [0.042 (0.012, 0.072) p = 0.01] and hip [0.067 (0.001, 0.133) p = 0.045] (beta coefficients show standard deviations change per doubling in impacts, with 95 % confidence interval). Higher impacts were positively associated with tibial periosteal circumference (PC) [0.015 (0.003, 0.027) p = 0.02], but unrelated to hip BMD. Equivalent positive associations were not seen for low or medium impacts.

CONCLUSIONS

Despite their rarity, habitual levels of higher impacts were positively associated with lower limb bone size and strength, whereas equivalent relationships were not seen for low or medium impacts.

Spinal radiographs in those with back pain-when are they appropriate to diagnose vertebral fractures?

The presence of an osteoporotic vertebral fracture improves fracture risk assessment and may change management, so it is vital for healthcare professionals to assess patients for the presence or absence of these fractures. This may be particularly important in the presence of back pain. However, the correlation between low back symptoms and spinal imaging results is poor and the pathophysiology of most low back pain is not known, leading to a common conclusion that spinal radiographs are not appropriate for the assessment of back pain. For individual patients with back pain, spinal radiographs should be considered if they have certain features in the history and examination. As well as the traditional risk factors for osteoporosis, self-reported descriptives of back pain and novel physical examination findings have been shown to make the presence of vertebral fractures more likely. Systematic approaches have the potential to improve bone health across the population but need to be targeted to be cost-effective. Spinal radiographs should be considered for individual older patients with back pain if they have certain additional features in the history and examination.

A novel accelerometer-based method to describe day-to-day exposure to potentially osteogenic vertical impacts in older adults: findings from a multi-cohort study

This observational study assessed vertical impacts experienced in older adults as part of their day-to-day physical activity using accelerometry and questionnaire data. Population-based older adults experienced very limited high-impact activity. The accelerometry method utilised appeared to be valid based on comparisons between different cohorts and with self-reported activity.

INTRODUCTION

We aimed to validate a novel method for evaluating day-to-day higher impact weight-bearing physical activity (PA) in older adults, thought to be important in protecting against osteoporosis, by comparing results between four cohorts varying in age and activity levels, and with self-reported PA levels.

METHODS

Participants were from three population-based cohorts, MRC National Survey of Health and Development (NSHD), Hertfordshire Cohort Study (HCS) and Cohort for Skeletal Health in Bristol and Avon (COSHIBA), and the Master Athlete Cohort (MAC). Y-axis peaks (reflecting the vertical when an individual is upright) from a triaxial accelerometer (sampling frequency 50 Hz, range 0-16 g) worn at the waist for 7 days were classified as low (0.5-1.0 g), medium (1.0-1.5 g) or higher (≥1.5 g) impacts.

RESULTS

There were a median of 90, 41 and 39 higher impacts/week in NSHD (age 69.5), COSHIBA (age 76.8) and HCS (age 78.5) participants, respectively (total n = 1512). In contrast, MAC participants (age 68.5) had a median of 14,322 higher impacts/week. In the three population cohorts combined, based on comparison of beta coefficients, moderate-high-impact activities as assessed by PA questionnaire were suggestive of stronger association with higher impacts from accelerometers (0.25 [0.17, 0.34]), compared with medium (0.18 [0.09, 0.27]) and low impacts (0.13 [0.07,0.19]) (beta coefficient, with 95 % CI). Likewise in MAC, reported moderate-high-impact activities showed a stronger association with higher impacts (0.26 [0.14, 0.37]), compared with medium (0.14 [0.05, 0.22]) and low impacts (0.03 [-0.02, 0.08]).

CONCLUSIONS

Our new accelerometer method appears to provide valid measures of higher vertical impacts in older adults. Results obtained from the three population-based cohorts indicate that older adults generally experience very limited higher impact weight-bearing PA.

A systematic review and meta-analysis of the association between eating disorders and bone density

This meta-analysis investigates the effect of an eating disorder on bone mineral density in two eating disorder subtypes. Following conflicting findings in previous literature, this study finds that not only anorexia nervosa, but also bulimia nervosa has a detrimental effect on BMD. Key predictors of this relationship are discussed. This systematic review and meta-analysis investigates bone mineral density (BMD) in individuals with anorexia nervosa (AN) and bulimia nervosa (BN) in comparison to healthy controls (HCs). AN has been associated with low BMD and a risk of fractures and mixed results have been obtained for the relationship between BN and BMD. Deciphering the effect these two ED subtypes on BMD will determine the effect of low body weight (a characteristic of AN) versus the effects of periods of restrictive eating and malnutrition which are common to both AN and BN. We conducted a systematic search through the electronic databases MedLine, EMBASE and PsychInfo and the Cochrane Library to investigate and quantify this relationship. We screened 544 articles and included 27 studies in a random-effect meta-analysis and calculated the standardised mean difference (SMD) in BMD between women with a current diagnosis of AN (n = 785) vs HCs (n = 979) and a current diagnosis of BN (n = 187) vs HCs (n = 350). The outcome measures investigated were spinal, hip, femoral neck and whole body BMD measured by DXA or DPA scanning. A meta-regression investigated the effect of factors including age, duration since diagnosis, duration of amenorrhea and BMI on BMD. The mean BMI of participants was 16.65 kg/m(2) (AN), 21.16 kg/m(2) (BN) and 22.06 kg/m(2) (HC). Spine BMD was lowest in AN subjects (SMD, -3.681; 95 % CI, -4.738, -2.625; p < 0.0001), but also lower in BN subjects compared with HCs (SMD, -0.472; 95 % CI, -0.688, -0.255; p < 0.0001). Hip, whole body and femoral neck BMD were reduced to a statistically significant level in AN but not BN groups. The meta-regression was limited by the number of included studies and did not find any significant predictors. This meta-analysis confirms the association between low BMD and AN and presents a strong argument for assessing BMD not only in patients with AN, but also in patients with BN.

Using self-reports of pain and other variables to distinguish between older women with back pain due to vertebral fractures and those with back pain due to degenerative changes

Women with back pain and vertebral fractures describe different pain experiences than women without vertebral fractures, particularly a shorter duration of back pain, crushing pain and pain that improves on lying down. This suggests a questionnaire could be developed to identify older women who may have osteoporotic vertebral fractures.

INTRODUCTION

Approximately 12 % of postmenopausal women have vertebral fractures (VFs), but less than a third come to clinical attention. Distinguishing back pain likely to relate to VF from other types of back pain may ensure appropriate diagnostic radiographs, leading to treatment initiation. This study investigated whether characteristics of back pain in women with VF are different from those in women with no VFs.

METHODS

A case control study was undertaken with women aged ≥60 years who had undergone thoracic spinal radiograph in the previous 3 months. Cases were defined as those with VFs identified using the algorithm-based qualitative (ABQ) method. Six hundred eighty-three potential participants were approached. Data were collected by self-completed questionnaire including the McGill Pain Questionnaire. Chi-squared tests assessed univariable associations; logistic regression identified independent predictors of VFs. Receiver operating characteristic (ROC) curves were used to evaluate the ability of the combined independent predictors to differentiate between women with and without VFs via area under the curve (AUC) statistics.

RESULTS

One hundred ninety-seven women participated: 64 cases and 133 controls. Radiographs of controls were more likely to show moderate/severe degenerative change than cases (54.1 vs 29.7 %, P = 0.011). Independent predictors of VF were older age, history of previous fracture, shorter duration of back pain, pain described as crushing, pain improving on lying down and pain not spreading down the legs. AUC for combination of these factors was 0.85 (95 % CI 0.79 to 0.92).

CONCLUSION

We present the first evidence that back pain experienced by women with osteoporotic VF is different to back pain related solely to degenerative change.

Natural history, reasons for, and impact of low/non-adherence to medications for osteoporosis in a cohort of community-dwelling older women already established on medication: a 2-year follow-up study

Approximately 15 % of older women on oral medications for osteoporosis could be considered for alternatives including parenteral therapies. Collection of data on socio-demographic/clinical variables is unlikely to be helpful in predicting low/non-adherence. Alternative approaches are needed to identify individuals at risk of low/non-adherence.

INTRODUCTION

This study aims to identify individual patient reasons for stopping medications for osteoporosis, and to investigate whether this can be predicted from knowledge about socio-demographic/clinical data, or whether alternative approaches need to be used.

METHODS

The Cohort for Skeletal Health in Bristol and Avon (COSHIBA) recruited 3200 older women from South West UK, of whom a proportion were on medications for osteoporosis at baseline. Information on self-reported adherence and reasons for low/non-adherence were collected at 6-monthly intervals over a 2-year period. Data was also collected on potential predictors of and impact of low/non-adherence.

RESULTS

Two hundred thirty-three of 3200 (7.3 %) women were on medications for osteoporosis at baseline. Mean length of time on treatment prior to enrolment was 46 months. Of those on osteoporosis medications, 94.9 % were on bisphosphonates; 8.5 % reported low adherence and 21.6 % stopped their medication completely over the 2-year follow-up period. Length of time on medication at baseline did not influence rates of low/non-adherence. Reasons for low/non-adherence to bisphosphonates included side effects (53.9 %), practical reasons such as forgetting to take them (18.0 %) and beliefs about medications (20.5 %). No convincing predictors of low/non-adherence were identified.

CONCLUSIONS

Approximately 15 % of older women on oral medications for osteoporosis could be considered for alternatives including parenteral therapies. This has important implications for healthcare provision. Collection of data on socio-demographic/clinical variables is unlikely to be helpful in predicting low/non-adherence. Alternative approaches are needed to identify individuals at risk of low/non-adherence to osteoporosis medications.

Broadening the examination of sociocultural constructs relevant to African-American colorectal cancer screening

The importance of sociocultural constructs as influences on cancer attitudes and screening has been established in the literature. This paper reports on the efforts to explore alternatives to sociocultural constructs previously associated with African-American cancer screening, but with low acceptance among community members or incomplete measurement (empowerment and collectivism) and develop a measure for a recently identified construct of interest (privacy). We report preliminary psychometric data on these sociocultural scales and their associations with cancer attitudes. African-Americans (N = 1021), 50-75 years of age participated in this study. Participants were identified via a listed sample and completed a telephone survey administered via call center. Sociocultural attitudes were assessed using items identified through computerized database searches, reviewed by advisory panels, edited and tested using cognitive response strategies. Cancer screening pros and cons, cancer worry, perceived cancer risk, colorectal cancer (CRC) screening subjective norms, and perceived self-efficacy for colorectal cancer screening (CRCS) were also assessed. Confirmatory factor analyses and multivariate analyses were conducted to provide support for the validity of the constructs and to understand the associations among the selected sociocultural constructs (empowerment, collectivism, and privacy) and cancer beliefs and attitudes (CRC perceived benefits and barriers, perceived risks, subjective norms, and perceived behavioral control/self-efficacy). Consistent with the literature, the factor analytic model (RMSEA for the model was .062; 90% CI: .060-.065) provided support for the empowerment, collectivism, and privacy constructs. The modified collectivism and privacy scales had acceptable reliability. The privacy scale demonstrated the strongest associations with measures of cancer beliefs and attitudes. The implication of the findings and need for further scale development activities is discussed.

Vertebral fracture assessment (VFA) by lateral DXA scanning may be cost-effective when used as part of fracture liaison services or primary care screening

SUMMARY

We identified that use of VFA may be cost-effective in either selected women from primary care or women attending after a low trauma fracture.

INTRODUCTION

Lateral DXA scanning of the spine for vertebral fracture assessment (VFA) is used for research, but its wider role is unclear. We aimed to establish whether VFA is cost-effective in women based on two different scenarios: following a low-trauma fracture, and after screening of high-risk women identified in primary care.

METHODS

The fracture cohort (FC) consisted of 377 women and the primary care cohort (PCC) of 251. Vertebral fractures were identified on VFA images by quantitative morphometry (QM). Outcome was cost-effectiveness of VFA, based on predicted change in clinical management defined as the identification of a vertebral fracture in a patient who otherwise falls below the threshold for treatment. FRAX treatment thresholds assessed were (1) 20/3 % thresholds and (2) National Osteoporosis Guidelines Group (NOGG) thresholds.

RESULTS

As a result, 9.8 % from FC and 13.9 % from PCC were identified with vertebral fractures. Management was changed in 21 to 22/377 (5.6-5.8 %) in FC and 12 to 26/251 (4.8-10.4 %) from PCC depending on which thresholds were used. Sensitivity analyses identified medication adherence as the assumption which most influenced the model. The best-estimate cost-per-QALY for use of VFA in FC was £3,243 for 20/3 threshold and £2,130 for NOGG; for PCC, this was £7,831 for 20/3 and was cost-saving for NOGG. Further analyses to adjust for potential false-positive vertebral fracture identification with QM showed VFA was no longer cost-effective.

CONCLUSION

VFA appears to be cost-effective in routine clinical practise, particularly when relatively inaccurate methods of identification of vertebral fractures are used such as QM.

Children with low muscle strength are at an increased risk of fracture with exposure to exercise

OBJECTIVES

To use objective measures of physical fitness and muscle function to assess the interplay between exercise, muscle and fractures during childhood.

METHODS

A cross-sectional analysis was performed using The Young Hearts Project, a population-based cohort recruited from Northern Ireland. Grip strength was assessed with a hand-held dynamometer. Aerobic fitness was assessed using the 20-metre endurance shuttle run. The outcome of interest was reported fractures. Data were also collected on other potential confounders.

RESULTS

There were 787 boys (49.5%) and 803 girls aged 13.9±1.5 years. 414 (26.0%) children reported a fracture at anytime since birth. There was a positive association between higher aerobic fitness and reported fracture (OR 1.23, 95%CI 1.05 to 1.45, P=0.012) greatest in those with lowest grip strength (OR 2.10, 95%CI 1.23 to 3.31, P=0.005). Conversely, in those with highest grip strength, no association was seen between aerobic fitness and reported fractures.

CONCLUSION

In children, higher levels of aerobic fitness are associated with an increased risk of fractures, with the greatest risk seen in those with low muscle strength. Our results suggest that there is the potential for exercise protocols that aim to strengthen forearm musculature to reduce upper limb fractures in adolescents.

In Vitro Growth of Acremonium coenophialum, an Endophyte of Toxic Tall Fescue Grass

Acremonium coenophialum, an endophytic fungus present in toxic tall fescue grass and seed, grew very slowly or not at all with conventional media and cultural practices. However, a considerable increase in growth was achieved in a relatively dilute medium consisting solely of glucose and yeast extract. The optimal levels of glucose and yeast extract were 3 to 6% and 0.35% (wt/vol), respectively. The addition of salts which lowered the pH suppressed growth. Even when the pH was controlled, the addition of KH(2)PO(4) at a level of 3.2% or more greatly inhibited growth. A. coenophialum grew better in shake culture than in stationary culture. The optimal temperature was 23 degrees C, and the optimal pH was 6.5.

Gender differences in the ratio between humerus width and length are established prior to puberty

SUMMARY

On a sample of 1,317 children aged 9.9 years we developed a novel method of measuring humeral dimensions from total body dual-energy X-ray absorptiometry (DXA) scans and showed that gender differences in the ratio between humeral width and length are established prior to puberty.

INTRODUCTION

It is recognised that long bone cross-sectional area is greater in males compared to females, which is thought to reflect more rapid periosteal bone growth in boys. However, it is currently unclear whether these findings reflect gender differences in bone size or shape. In the present study, we investigated whether gender differences exist in the balance between longitudinal and periosteal long bone growth in children, leading to gender differences in bone shape, based on a novel method for evaluating shape of the humerus. We also examined whether these differences are established prior to puberty.

METHODS

Length, area and width of the humerus were estimated from total body DXA scans in 1,317 children aged 9.9 +/- 0.33 years, who had participated in a nested case-control study of fractures within the Avon Longitudinal Study of Parents and Children (ALSPAC) (a geographically based birth cohort based in South West England). No differences were observed with respect to parameters of humeral geometry according to fracture history, and so both groups were pooled for further analysis. Aspect ratio (AR) of the humerus was calculated as humeral width divided by length. Total body height and weight were measured at the same time as the DXA scan. Puberty was assessed using self-completion questionnaires.

RESULTS

Humeral width and length were positively associated with age and height in boys and girls combined (P<0.001), and with Tanner stage in girls (P<0.002). In contrast, age, height and Tanner stage were not related to humeral AR. We then examined gender differences in humeral shape according to pubertal stage. In prepubertal children (i.e. Tanner stage 1), humeral length was similar in boys and girls, but width (1.92 vs 1.88 cm, P<0.001) and area (47.7 vs 46.9 cm(2), P<0.001) were greater in boys, resulting in a greater AR (7.78 vs 7.53, P<0.001). Similar gender differences were observed in early pubertal children (i.e. Tanner stage 2).

CONCLUSION

We conclude that the greater periosteal diameter of boys compared to girls reflects differences in the balance between longitudinal and periosteal bone growth. Interestingly, resulting gender differences in humeral AR are established in prepubertal children.

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.

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.

Characterization of the indole-3-acetic acid (IAA) biosynthetic pathway in an epiphytic strain of Erwinia herbicola and IAA production in vitro

An epiphytic strain of Erwinia herbicola (strain 299R) synthesized indole-3-acetic acid (IAA) from indole-3-pyruvic acid and indole-3-acetaldehyde, but not from indole-3-acetamide and other intermediates of various IAA biosynthetic pathways in enzyme assays. TLC, HPLC, and GC–MS analyses revealed the presence of indole-3-pyruvic acid, indole-3-ethanol, and IAA in culture supernatants of strain 299R. Indole-3-acetaldehyde was detected in enzyme assays. Furthermore, strain 299R genomic DNA shared no homology with the iaaM and iaaH genes from Pseudomonas syringae pv. savastanoi, even in Southern hybridizations performed under low-stringency conditions. These observations strongly suggest that unlike gall-forming bacteria which can synthesize IAA by indole-3-acetamide, the indole-3-pyruvic acid pathway is the primary route for IAA biosynthesis in this plant-associated strain. IAA synthesis in tryptophan-supplemented cultures of strain 299R was over 10-fold higher under nitrogen-limiting conditions, indicating a possible role for IAA production by bacterial epiphytes in the acquisition of nutrients during growth in their natural habitat.Key words: indole-3-acetic acid, Erwinia, tryptophan, indole-3-pyruvic acid, nitrogen.

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.

Major tendon repairs with dacron vascular graft suture

Achilles and patellar tendon tears in nine patients were repaired with 5 mm Dacron vascular grafts. There have been no failures with this method of fixation. In the patients we studied this method permitted earlier mobilization of joints.

Satellite DNA in large marker chromosomes of methotrexate-resistant mouse cells

The additional segments of five large marker chromosomes of methotrexate-resistant mouse melanoma PG19T3 cells are shown to consist of C-banding material. In situ hybridization indicates that these additional segments also contain a high proportion of sequences that will cross hybridize with mouse satellite DNA. Analytical density gradient centrifugation suggests that up to 60% of the DNA in the additional segments may be in the form of satellite DNA. Incorporation of bromodeoxyuridine for one complete S phase and staining with the Hoechst 33258 fluorescence plus Giemsa technique reveals complex asymmetries within the additional segments. These asymmetries are interpreted as showing a large repeating unit, which is likely to be involved in the amplification of the dihydrofolate reductase gene.

Errors in a computerized medical records system (CLINICS)

The accuracy of computer-held medical information can 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 correction programs. This paper reports on the errors which were detected by checking the consistency between stored data and incoming data (context checks), in Southampton University Primary Medical Care computer system (CLINICS). The majority of detected errors 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). 7% of incoming data had errors detected by the context checking program and subsequently corrected; we calculate that the stored data contains less than 1% in error.

The development of resistance to methotrexate in a mouse melanoma cell line. I. Characterisation of the dihydrofolate reductases and chromosomes in sensitive and resistant cells

PG19T3 mouse melanoma cells were selected for resistance to methotrexate. Nine sub-lines that are resistant to concentrations of methotrexate ranging from 1.27 x 10(-7) M, to 1 x 10(-4) M methotrexate were selected and characterised in terms of their content of dihydrofolate reductase activity and their chromosomes. The intracellular level of dihydrofolate reductase activity increases with increasing resistance such that at the highest level of resistance PG19T3:MTXR10(-4)M cells contain approximately 1,000 fold more enzyme activity than the parental PG19T3 cells. It is shown that the enhanced activity is due to an increase in the amount of the enzyme rather than any structural change to the enzyme in resistant cells. Comparisons of pH activity profiles, profiles under different activating conditions and titrations with methotrexate suggest that the sensitive and resistant cells contain identical dihydrofolate reductases. Analysis of the chromosomes of resistant cells shows the presence of up to 5 large marker chromosomes which contain homogeneously staining regions after G-banding. These same regions stain intensely after C-banding and fluoresce brightly after staining with Hoechst 33258. The size of homogeneously staining regions increases throughout the process of selection. For one marker chromosome this increase may have been mediated via a ring chromosome.