Sponsorship bias and quality of randomised controlled trials in veterinary medicine.

BACKGROUND: Randomised controlled trials (RCTs) are considered the gold standard form of evidence for assessing treatment efficacy, but many factors can influence their reliability including methodological quality, reporting quality and funding source. The aim of this study was to examine the relationship between funding source and positive outcome reporting in veterinary RCTs published in 2011 and to assess the risk of bias in the RCTs identified. METHODS: A structured search of PubMed was used to identify feline, canine, equine, bovine and ovine clinical trials examining the efficacy of pharmaceutical interventions published in 2011. Funding source and outcomes were extracted from each RCT and an assessment of risk of bias made using the Cochrane risk of bias tool. RESULTS: Literature searches returned 972 papers, with 86 papers (comprising 126 individual RCTs) included in the analysis. There was found to be a significantly higher proportion of positive outcomes reported in the pharmaceutical funding group (P) compared to the non-pharmaceutical (NP) and 'no funding source stated' (NF) groups (P = 56.9%, NP = 34.9%, NF = 29.1%, p < 0.05). A high proportion of trials had an unclear risk of bias across the five criteria examined. CONCLUSIONS: We found evidence that veterinary RCTs were more likely to report positive outcomes if they have pharmaceutical industry funding or involvement. Consistently poor reporting of trials, including non-identification of funding source, was found which hinders the use of the available evidence.

Sample size and number of outcome measures of veterinary randomised controlled trials of pharmaceutical interventions funded by different sources, a cross-sectional study.

BACKGROUND: Randomised controlled trials (RCTs) are a key component of the veterinary evidence base. Sample sizes and defined outcome measures are crucial components of RCTs. To describe the sample size and number of outcome measures of veterinary RCTs either funded by the pharmaceutical industry or not, published in 2011. METHODS: A structured search of PubMed identified RCTs examining the efficacy of pharmaceutical interventions. Number of outcome measures, number of animals enrolled per trial, whether a primary outcome was identified, and the presence of a sample size calculation were extracted from the RCTs. The source of funding was identified for each trial and groups compared on the above parameters. RESULTS: Literature searches returned 972 papers; 86 papers comprising 126 individual trials were analysed. The median number of outcomes per trial was 5.0; there were no significant differences across funding groups (p = 0.133). The median number of animals enrolled per trial was 30.0; this was similar across funding groups (p = 0.302). A primary outcome was identified in 40.5% of trials and was significantly more likely to be stated in trials funded by a pharmaceutical company. A very low percentage of trials reported a sample size calculation (14.3%). CONCLUSIONS: Failure to report primary outcomes, justify sample sizes and the reporting of multiple outcome measures was a common feature in all of the clinical trials examined in this study. It is possible some of these factors may be affected by the source of funding of the studies, but the influence of funding needs to be explored with a larger number of trials. Some veterinary RCTs provide a weak evidence base and targeted strategies are required to improve the quality of veterinary RCTs to ensure there is reliable evidence on which to base clinical decisions.

A randomised controlled trial comparing TVT, Pelvicol and autologous fascial slings for the treatment of stress urinary incontinence in women.

OBJECTIVE: To compare TVT(TM) , Pelvicol(TM) and autologous fascial slings (AFSs). DESIGN: A multicentre randomised control trial. SETTING: Four units in the UK. POPULATION: Women requiring primary surgery for stress urinary incontinence (SUI). METHODS: A total of 201 women with urodynamically proven stress incontinence were randomised into three groups and assessed at baseline, 6 weeks, 6 months and 1 year. MAIN OUTCOME MEASURE: The primary outcome was patient-reported improvement rates. Secondary outcomes included operative complications/time, intermittent self-catheterisation (ISC) and re-operation rates. The quality-of-life tools used were the Bristol Female Lower Urinary Tract Symptoms (BFLUTS) and EuroQoL. RESULTS: Fifty women had a Pelvicol(TM) sling, 79 had AFSs and 72 had TVT(TM). At 6 months the Pelvicol(TM) arm had poorer improvement rates (73%) than TVT(TM) (92%)/AFS (95%); P=0.003. At 1 year only 61% of the Pelvicol(TM) slings remained as improved, versus 93% of TVTs and 90% of AFSs (P<0.001). Pelvicol(TM) has poorer dry rates (22%) than TVT(TM) (55%)/AFS (48%) (P=0.001) at 1 year; hence, the Pelvicol(TM) arm was suspended following interim analysis. There is no difference in the success rates between TVT(TM) and AFS. One in five women in the Pelvicol(TM) arm had further surgery for SUI by 1 year, but none required further surgery in the other arms. AFS took longer to do (54 minutes versus 35 minutes for TVT(TM) /36 minutes for Pelvicol(TM) ) and had higher ISC rates (9.9 versus 0% Pelvicol(TM) /TVT(TM) 1.5%). Hospital stay was shortest for TVT(TM) (2 days). Most BFLUTS domains showed improvement in all three arms. The improvement for women in the Pelvicol(TM) arm, however, was less than for women in the other arms in several key domains. CONCLUSIONS: Pelvicol(TM) cannot be recommended for the management of SUI. TVT(TM) does not have greater efficacy than AFS, but does utilise fewer resources.

Extracorporeal magnetic energy stimulation of pelvic floor muscles for urodynamic stress incontinence of urine in women.

The aim of this study was to assess the efficacy, side effects and drop out rate of extra-corporeal magnetic energy stimulation of pelvic floor muscles for urodynamic stress incontinence of urine in women. It was a prospective non-controlled study at 2 district general hospitals in South Wales. It included 48 female patients with urodynamic stress incontinence of urine, who had 16, twice weekly treatment sessions. Pad test was the primary outcome measure and continence diary, King's Health and EuroQol quality of life questionnaires, side effects and drop out were the secondary outcome measures. Assessment was made on recruitment, at the end of treatment sessions and at 3 months follow up. Thirty one patients completed treatment sessions and 27 attended for follow up at 3 months. There was no significant change in outcome measures at the end of treatment or at 3 months follow up. Side effects were encountered by 52.1% of patients and the drop out rate was 35.4%.

Effects of low-dose cimetidine on nocturnal acid secretion in healthy subjects.

The effects of 100 mg and 200 mg bedtime doses of cimetidine on nocturnal gastric acid secretion were examined in nine healthy subjects in a double blind, placebo controlled, randomised three way crossover study. Treatment was given at 23.00 hours and the gastric contents continually aspirated from midnight until 07.00 hours the following morning. Hourly aliquots were analysed for pH and acid output. Relative to placebo the 100 mg and 200 mg doses of cimetidine respectively increased mean pH by 2.22 and 2.63 units/h (P less than 0.001) with mean acid output decreasing by 0.95 and 0.98 mmol/h (P less than 0.001). Whilst mean pH was higher and mean acid output was lower for 200 mg cimetidine compared to 100 mg cimetidine the difference was not statistically significant. Mean hourly pH was consistently above pH 3 for 100% of the time for both doses of cimetidine whereas mean pH failed to reach this value at anytime on placebo. Low doses of cimetidine taken at bedtime effectively reduced nocturnal gastric acid secretion in healthy individuals.

Practice characteristics associated with audit activity: a medical audit advisory group survey.

AIM: A survey of general practices in West Glamorgan was carried out to assess the development of record systems and practice organization and to relate this to audit activity. METHOD: Following mutual agreement practices were visited by two assessors. Visits were conducted using an agreed protocol and practice data were recorded on a semi-structured questionnaire, which had been sent to the practices in advance of the visits. Practices varied from single handed practices to group practices with six partners. RESULTS: Fifty seven of the 63 practices in the county suitable for inclusion were visited (90%). Data were analysed from 54 practices (three visits were regarded as a pilot). The practices more likely to be involved in audit were those with three or more partners and which had modern medical record systems. Audit activity had occurred in 87% of practices who kept clinical summaries in the notes (compared with 38% who did not), in 87% of practices with long-term medication summaries in the notes (compared with 40% with no summaries) and in 85% of practices with a computerized age-sex register (compared with 50% with no register). All training practices had undertaken audit compared with 63% of non-training practices. CONCLUSION: The survey enabled the medical audit advisory group to identify the type and degree of audit undertaken locally and highlighted the characteristics which encourage this activity. As a consequence the group is able to target practices who have limited or no involvement in audit and to offer assistance and advice on record modification likely to enhance audit activity.

Universal prophylaxis for Chlamydia trachomatis and anaerobic vaginosis in women attending for suction termination of pregnancy: an audit of short-term health gains.

A previous study of infection and morbidity in 400 women attending for termination of pregnancy (TOP) had shown that 32 (8%) harboured cervical Chlamydia trachomatis and 112 (28%) had anaerobic (bacterial) vaginosis (AV). Fifty-three per cent of the women with preoperative C. trachomatis had AV. Thirty of the 32 women with chlamydial infection were followed up and 19 (63%) of these developed post-abortion upper genital tract infection, 7 of whom needed re-admission. In view of the high morbidity in women with chlamydial infection attending for TOP, anti-bacterial prophylaxis with metronidazole suppositories and oral oxytetracycline was introduced for women attending for suction termination of pregnancy (STOP). An audit of the clinical and financial benefits and/or losses was carried out. The audit of 1951 consecutive patients attending for STOP revealed that 132 (6.8%) had chlamydial infection with equivocal results reported in a further 2 patients. One hundred and eight of the 134 women responded to recall. Full genital tract infection screening was carried out in 105 of the 108 recalled patients of whom 5 had repeat positive cervical swabs for C. trachomatis, one had Trichomonas vaginalis, 24 had candidiasis and 17 had anaerobic vaginosis, none had gonorrhoea. Thirteen (12%) of the 108 women had pelvic infection as previously defined, none of whom required re-admission. At least pound sterling 20,000 has been saved each year in our Trust following the introduction of pre-abortion chlamydial screening and universal antichlamydial and anti-anaerobe prophylaxis. The introduction of universal prophylaxis against C. trachomatis and AV has profoundly reduced morbidity in patients attending for TOP and has also resulted in substantial financial savings.

PIP: This paper presents an audit of the clinical and financial benefits and/or losses of a new management protocol for Chlamydia trachomatis and anaerobic vaginosis (AV) in women requesting suction termination of pregnancy (STOP). This management protocol is known as the Singleton Regimen and involves the introduction of an antibacterial prophylaxis with metronidazole suppositories and oral oxytetracycline. The audit included 1951 patients requesting STOP at the Singleton Hospital between January 1992 and October 1993; 132 of them had chlamydial infection. A total of 108 women responded to recall. Full genital tract infection screening was carried out in 105 of the 108 recalled patients. Of the 105 patients, 5 had repeat positive cervical swabs for C. trachomatis, 1 had Trichomonas vaginalis, 24 had candidiasis, and 17 had anaerobic vaginosis. 13 of the 108 women had pelvic infection; none of them required readmission. In conclusion, the introduction of universal prophylaxis against C. trachomatis and AV has significantly reduced morbidity in patients obtaining a termination of pregnancy and has also resulted in substantial financial savings.

A high-dose preparation of lactobacilli and bifidobacteria in the prevention of antibiotic-associated and Clostridium difficile diarrhoea in older people admitted to hospital: a multicentre, randomised, double-blind, placebo-controlled, parallel arm trial (PLACIDE).

BACKGROUND: Antibiotic-associated diarrhoea (AAD) occurs most commonly in older people admitted to hospital and within 12 weeks of exposure to broad-spectrum antibiotics. Although usually a mild and self-limiting illness, the 15-39% of cases caused by Clostridium difficile infection [C. difficile diarrhoea (CDD)] may result in severe diarrhoea and death. Previous research has shown that probiotics, live microbial organisms that, when administered in adequate numbers, are beneficial to health, may be effective in preventing AAD and CDD. OBJECTIVES: To determine the clinical effectiveness and cost-effectiveness of a high-dose, multistrain probiotic in the prevention of AAD and CDD in older people admitted to hospital. DESIGN: A multicentre, randomised, double-blind, placebo-controlled, parallel-arm trial. SETTING: Medical, surgical and elderly care inpatient wards in five NHS hospitals in the UK. PARTICIPANTS: Eligible patients were aged ≥ 65 years, were exposed to one or more oral or parenteral antibiotics and were without pre-existing diarrhoeal disorders, recent CDD or at risk of probiotic adverse effects. Out of 17,420 patients screened, 2981 (17.1%) were recruited. Participants were allocated sequentially according to a computer-generated random allocation sequence; 1493 (50.1%) were allocated to the probiotic and 1488 (49.9%) to the placebo arm. INTERVENTIONS: Vegetarian capsules containing two strains of lactobacilli and two strains of bifidobacteria (a total of 6 × 10(10) organisms per day) were taken daily for 21 days. The placebo was inert maltodextrin powder in identical capsules. MAIN OUTCOME MEASURES: The occurrence of AAD within 8 weeks and CDD within 12 weeks of recruitment was determined by participant follow-up and checking hospital laboratory records by research nurses who were blind to arm allocation. RESULTS: Analysis based on the treatment allocated included 2941 (98.7%) participants. Potential risk factors for AAD at baseline were similar in the two study arms. Frequency of AAD (including CDD) was similar in the probiotic (159/1470, 10.8%) and placebo arms [153/1471, 10.4%; relative risk (RR) 1.04; 95% confidence interval (CI) 0.84 to 1.28; p = 0.71]. CDD was an uncommon cause of AAD and occurred in 12/1470 (0.8%) participants in the probiotic and 17/1471 (1.2%) in the placebo arm (RR 0.71; 95% CI 0.34 to 1.47; p = 0.35). Duration and severity of diarrhoea, common gastrointestinal symptoms, serious adverse events and quality of life measures were also similar in the two arms. Total health-care costs per patient did not differ significantly between the probiotic (£8020; 95% CI £7620 to £8420) and placebo (£8010; 95% CI £7600 to £8420) arms. CONCLUSION: We found no evidence that probiotic administration was effective in preventing AAD. Although there was a trend towards reduced CDD in the probiotic arm, on balance, the administration of this probiotic seems unlikely to benefit older patients exposed to antibiotics. A better understanding of the pathogenesis of AAD and CDD and the strain-specific effects of probiotics is needed before further clinical trials of specific microbial preparations are undertaken. Evaluation of the effectiveness of other probiotics will be difficult where other measures, such as antibiotic stewardship, have reduced CDD rates. TRIAL REGISTRATION: This trial is registered as ISRCTN70017204. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 57. See the NIHR Journals Library website for further project information.

A Randomised, Cross-Over, Placebo-Controlled Study of Aloe vera in Patients with Irritable Bowel Syndrome: Effects on Patient Quality of Life.

Background. Irritable bowel syndrome (IBS) is a chronic, difficult to treat condition. The efficacy of Aloe vera in treating IBS symptoms is not yet proven. The purpose of this study was to determine if Aloe vera is effective in improving quality of life. Methods. A multicentre, randomised, double-blind, cross-over placebo controlled study design. Patients were randomised to Aloe vera, wash-out, placebo or placebo, washout, Aloe vera. Each preparation (60 mL) was taken orally twice a day. Patient quality of life was measured using the Gastrointestinal Symptoms Rating Score, Irritable Bowel Syndrome Quality of Life, EuroQol and the Short-Form-12 at baseline and treatment periods 1 and 2. Results. A total of 110 patients were randomised, but only 47 completed all questionnaires and both study arms. Statistical analysis showed no difference between the placebo and Aloe vera treatment in quality of life. Discussion. This study was unable to show that Aloe vera was superior to placebo in improving quality of life. Drop outs and other confounding factors may have impacted on the power of the study to detect a clinically important difference. Conclusion. This study failed to find Aloe vera superior to placebo in improving quality of life proven Irritable Bowel Syndrome patients.

Effects of short-term therapy with glibenclamide and repaglinide on incretin hormones and oxidative damage associated with postprandial hyperglycaemia in people with type 2 diabetes mellitus.

AIM: To examine the effects of glibenclamide and repaglinide on glucose stimulated insulin release, incretins, oxidative stress and cell adhesion molecules in patients with type 2 diabetes suboptimally treated with metformin. METHODS: A randomized clinical trial was performed recruiting 27 subjects (HbA(1c) between 7.5 and 10.5%) free from cardiovascular and renal disease. Glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), total antioxidant status, F(2)-isoprostane, interleukin-6 and cell adhesion molecules were measured during an oral glucose load at baseline and after eight weeks of treatment. The areas under the curve were analysed at 45, 60 and 120 min (AUC(45), AUC(60), AUC(120)). RESULTS: Significant improvements in glucose were observed with repaglinide (HBA(1c): -1.5%, fasting glucose: -2.8 mmol/L, 2-h glucose: -3.7 mmol/L, AUC(120): -18.9%) and glibenclamide (-1.0%, -2.2 mmol/L, -2.5 mmol/L, -17.5%). Repaglinide was also associated with an increase in the AUC(60) and AUC(120) for insulin (+56%, +61%) and C-peptide (+41%, +36%). GLP-1, GIP, IL-6, ICAM-1 and E-selectin levels did not change in either group. No association was observed between GLP-1, GIP-1 and plasma markers of oxidative stress. CONCLUSION: Repaglinide is associated with improved postprandial glycaemic control via insulin and C-peptide release. We observed no direct effects of glibenclamide or repaglinide on plasma levels of GLP-1 or GIP. We observed no associations of GLP-1 and GIP with plasma markers of oxidative stress.

Social health outcomes following thermal injuries: a retrospective matched cohort study.

INTRODUCTION: Over 50% of children admitted with burns are aged under 3 years. US studies suggest that up to 26% of childhood burns are non-accidental, although UK reports are lower (1-16%). OBJECTIVES: To determine the social health outcomes of burned children as regards the number of children abused, neglected or "in need" before the age of 6 years compared with matched controls. METHODS: A retrospective matched cohort study. 145 children aged under 3 years admitted for burns in 1994-1997 were matched with controls for sex, age and enumeration district and followed up until 2003. Electronic routine databases provided study data on local authority care episodes and Social Services referrals by age 6 years. RESULTS: 89.0% of cases had accidental burns and four cases (2.8%) had non-accidental burns. No case was attributed to neglect. By their sixth birthday cases were statistically more likely to have been referred to Social Services with 14 (9.7%) of the burned children having been abused or neglected versus two (1.4%) controls (95% CI 0.030 to 0.13, p = 0.004). Forty six (32%) cases versus 26 (18%) controls were defined as "in need" (95% CI 0.047 to 0.23, p = 0.006). CONCLUSION: Although most burns were deemed accidental, 2.8% were categorised as non-accidental at presentation. Almost a third of the burned children went on to be "in need". Children with a burn appear to be at higher risk of further abuse or neglect compared with controls. A burn therefore could be a surrogate marker indicating need for closer supervision and follow-up by professionals.

Functional evidence for the expression of P2X1, P2X4 and P2X7 receptors in human lung mast cells.

BACKGROUND AND PURPOSE: P2X receptors are widely expressed in cells of the immune system with varying functions. This study sought to characterize P2X receptor expression in the LAD2 human mast cell line and human lung mast cells (HLMCs). EXPERIMENTAL APPROACH: Reverse transcriptase polymerase chain reaction (RT-PCR) and patch clamp studies were used to characterize P2X expression in mast cells using a range of pharmacological tools. KEY RESULTS: RT-PCR revealed P2X1, P2X4 and P2X7 transcripts in both cell types; mRNA for P2X6 was also detected in LAD2 cells. Under whole-cell patch clamp conditions, rapid application of ATP (1-1000 microM) to cells clamped at -60 mV consistently evoked inward currents in both types of cells. Brief application of ATP (1 s) evoked a rapidly desensitizing P2X1-like current in both cell types. This current was also elicited by alphabetamethylene ATP (10 microM, 94% cells, n= 31) and was antagonized in LAD2 cells by NF 449 (1 microM) and pyridoxal phosphate-6-azo(benzene-2,4-disulphonic acid) (1-10 microM). A P2X7-like non-desensitizing current in response to high concentrations of ATP (1-5 mM) was also seen in both cell types (96% LAD2, n= 24; 54% HLMCs, n= 24) which was antagonized by AZ11645373 (1 microM). P2X7-like responses were also evoked in LAD2 cells by 2'(3')-0-(4-benzoylbenzoyl)ATP (300 microM). A P2X4-like current was evoked by 100 microM ATP (80% LAD2, n= 10; 21% HLMCs, n= 29), the amplitude and duration of which was potentiated by ivermectin (3 microM). CONCLUSION AND IMPLICATIONS: Our data confirmed the presence of functional P2X1, P2X4 and P2X7 receptors in LAD2 cells and HLMCs.

A prospective evaluation of the Modified Hand Injury Severity Score in predicting return to work.

Hand injuries are the main cause of work-related disability in young adults. We have devised the Modified Hand Injury Scoring System to quantify hand, wrist and forearm injuries. This study aims to determine its value in predicting ability and time taken to return to work after such injury. Prospectively-assigned MHISS at presentation was compared with demographic, injury, employment and quality of life information 40-52months after acute hand or forearm injury. MHISS score was the only variable investigated found to predict ability to return to work. Factors not associated included age at injury, occupation, hand injury side or dominance, main earner status and compensation-seeking. Median time to return to work increased from 30 to 760days for Mild and Major MHISS categories respectively. Injury severity quantified using MHISS is an important determinant of return to work after hand or forearm injury. Only 60% of patients return to work following a Major injury and may take over a year to do so. Such information may allow the patient to make early informed personal financial and retraining decisions after their injury.

A randomised controlled trial comparing two autologous fascial sling techniques for the treatment of stress urinary incontinence in women: short, medium and long-term follow-up.

This randomised control trial compares full-length autologous slings (Group A: 81 women) with a modified "sling-on-a-string" (Group B: 84 women) technique for the treatment of stress urinary incontinence (SUI). Primary outcomes are quality of life (QoL) scores; Group A/Group B. The IIQ-7 scores decrease from 1.91/1.85 at baseline to 0.65/0.72 at 12 months and 0.85/0.92 at +5 years. The UDI-6 scores decrease from 1.85/1.61 at baseline to 0.66/0.62 at 12 months and 1.22/1.08 at +5 years. The incidence of SUI is 13% at 3 months but averages 53% at +5 years. Both techniques offer similar improvements. The shorter sling is quicker, less painful and with less hospital readmissions. The 'sling-on-a-string' technique is as effective as the standard technique with better short-term sequelae. The incidence of SUI post-autologous slings rises over the long term.

Botulinum toxin B is not an effective treatment of refractory overactive bladder.

OBJECTIVES: To determine the efficacy and safety of botulinum toxin-B (BTX-B) in two groups of patients with urodynamically proven idiopathic detrusor overactivity (IDO) or neurogenic DO (NDO) refractory to conservative treatment. METHODS: This was a nonrandomized, prospective study. We diluted 5000 U of BTX-B in 20 mL of normal saline and injected it at 20 sites around the bladder, avoiding the trigone. The data collected at recruitment and 10 and 26 weeks postoperatively included number of incontinent episodes, frequency, and nocturia, King's Health Questionnaire score, and the urodynamic parameters of volume at the first overactive contraction and maximal cystometric capacity. RESULTS: A total of 25 patients were recruited, 20 with IDO and 5 with NDO. Only 7 patients, all with IDO, reported symptomatic improvement at the 10-week assessment. The symptoms had returned in these 7 patients at a median of 136 days (range 106 to 151) after injection. Of the remaining 20 patients, 16 (13 with IDO and 3 with NDO) thought an initial improvement had occurred but it had worn off or was wearing off by the first assessment. Two patients (both with NDO) reported no improvement. CONCLUSIONS: BTX-B had a limited duration of action, with most of its symptomatically beneficial effects wearing off by 10 weeks in most of our patients. The short duration of action for BTX-B suggests it is unlikely to gain widespread use in the treatment of DO.

Preventing fractures among older people living in institutional care: a pragmatic randomised double blind placebo controlled trial of vitamin D supplementation.

INTRODUCTION: Osteoporotic fractures in older people are a major and increasing public health problem. We examined the effect of vitamin D supplementation on fracture rate in people living in sheltered accommodation. METHODS: In a pragmatic double blind randomised controlled trial of 3 years duration, we examined 3,440 people (2,624 women and 816 men) living in residential or care home. We used four-monthly oral supplementation using 100,000 IU vitamin D(2) (ergocalciferol). As a main outcome measure, we used the incidence of first fracture using an intention to treat analysis. This was a multicentre study in 314 care homes or sheltered accommodation complexes in South Wales, UK. RESULTS: The vitamin D and placebo groups had similar baseline characteristics. In intention-to-treat analysis, 205 first fractures occurred in the intervention group during a total of 2,846 person years of follow-up (7 fractures per 100 people per year of follow-up), with 218 first fractures in the control group over 2,860 person years of follow-up. The hazard ratio of 0.95 (95% confidence interval 0.79-1.15) for intervention compared to control was not statistically significant. CONCLUSION: Supplementation with four-monthly 100,000 IU of oral vitamin D(2) is not sufficient to affect fracture incidence among older people living in institutional care.

Estimation of the primordial pool size of the mouse liver using a histochemically demonstrable X-linked enzyme in the adult female mouse.

We have used a histochemical technique to study cellular mosaicism in the livers of female mice heterozygous for an abnormal form of the X-linked enzyme ornithine carbamoyltransferase. The proportion of cells expressing the normal enzyme was found to be consistent within a liver lobe, but discordant between lobes, with as few as 4% or as many as 91% of cells being enzyme positive. Systematic observation of variation of the proportion of positive cells in different lobes of 12 mice was used to calculate the primordial pool size for each lobe and for the liver as a whole. Although confidence limits for this small study are wide, the data suggest that the liver pool is about 15 cells, and that it enlarges to at least 50 cells before subdividing into six lobe pools ranging in size from a minimum of 4 to a maximum of at least 14 cells.