Path analysis and sib-pair linkage

When the distance between linked loci is expressed in terms of the correlation between the identity-by-descent (idb) values of the loci, then a path model may be used to order loci with data on sib-pairs and their parents. The relationship between the recombination fraction and the correlation coefficient is developed and a method for fitting a covariance matrix predicted by a specific ordering of loci to an observed covariance matrix is proposed. © 1993 Wiley-Liss. Inc.     

Admission rates for peptic ulcer in the Trent Region, UK, 1972–2000: Changing pattern, a changing disease?

BACKGROUND AND AIM: Peptic ulcer disease is believed to be less common and less severe as a result of modern medical treatment. We therefore examined changes in the admission rates for patients with duodenal ulcer and gastric ulcer, both emergency (for haemorrhage, perforation or severe pain) and for elective surgery, before and since the introduction of the new advances in therapy. These admission indices reflect disease prevalence and severity. PATIENTS AND METHODS: We identified admission rates during 1972--2000 within the Trent Regional Health Authority, UK (population 4.7 million), from computerised patient information using diagnostic search codes ICD8-10 and expressed as rates per million resident population. Drug expenditure details were obtained from the Department of Health. RESULTS: Emergency admission rates as a whole changed little, a decline in the young being offset by an increase in the elderly. Haemorrhage was the most common reason (approximately 115 per million for duodenal ulcer and 87 for gastric ulcer) throughout [compared with perforation (80 and 21) and pain (90 and 68)]. In contrast, elective surgery has almost disappeared; this reduction began before the introduction of modern treatment. CONCLUSION: Emergency admission rates for duodenal and gastric ulcer for complications or severe pain have fluctuated over the last three decades but with little overall change. In contrast, elective surgery has declined dramatically, as a result of advances in treatment but also from changes in the natural history.     

Obstetric risk assessment in rural practice

A study was undertaken to evaluate Coopland's obstetric risk index in a rural primary care setting. Information on 635 pregnant women cared for in a rural practice was collected prospectively. Adverse outcome was defined as perinatal death, birthweight less than 2500 g, 5-minute Apgar score less than 7, or newborn transferred to a level 2 or level 3 nursery. Forty-seven pregnancies (8.3%) had an adverse outcome. There was a clear relationship between risk score and probability of adverse outcome. Good sensitivity could be achieved only at the expense of a very high false-positive rate, however. The index can be used to identify a subgroup of women at relatively high risk for adverse outcome, but the majority of adverse outcomes will occur in women identified as low risk. The risk-scoring system in this population was no more effective than a policy that would refer all women with standard obstetric risk factors.     

Risk of Clostridium difficile-associated disease among patients receiving proton-pump inhibitors in a Quebec medical intensive care unit.

Our study was conducted to determine whether use of gastric acid-suppressive agents increased the risk of Clostridium difficile-associated disease (CDAD) in a medical intensive care unit of one of the first hospitals to be threatened by the current CDAD epidemic in Quebec, Canada. Our findings suggest that efforts to determine risk factors for CDAD should focus on other areas, such as older age and antibiotic use.     

Meta-analysis of placebo-controlled studies of the efficacy of Epogam in the treatment of atopic eczema. Relationship between plasma essential fatty acid changes and clinical response

Gamma-linolenic acid in the form of a particular variety of evening primrose oil (Epogam) has been reported of value in the treatment of atopic eczema. Nine controlled trials of evening primrose oil were performed in eight centres. Four of the trials were parallel and five cross-over. Doctors and patients assessed the severity of eczema by scoring measures of inflammation, dryness, scaliness, pruritus and overall skin involvement. Individual symptom scores were combined to give a single global score at each assessment point. In the analysis of the parallel studies, both patient and doctor scores showed a highly significant improvement over baseline (P less than 0.0001) due to Epogam: for both scores the effect of Epogam was significantly better than placebo. Similar results were obtained on analysis of the cross-over trials, but in this case the difference between Epogam and placebo in the doctors' global score, although in favour of Epogam, failed to reach significance. The effects on itch were particularly striking. There was no placebo response to this symptom, whereas there was a substantial and highly significant response to Epogam (P less than 0.0001). When the improvements, or otherwise, in clinical condition were related to changes in plasma levels of dihomogammalinolenic and arachidoni acids, it was found that there was a positive correlation between an improvement in clinical score and a rise in the fatty acid levels.     

Determinants of health-service use by low-income people.

Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.     

Ultrasensitive analysis of the intestinal absorption and compartmentalization of aluminium in uraemic rats: a 26Al tracer study employing accelerator mass spectrometry

BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit the determination of femtogram amounts of 26Al in blood and in various tissues with good precision and free of external contamination. METHODS: In the present study we used trace quantities of 26Al to investigate the intestinal absorption and compartmentalization of aluminium in rats with renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single oral doses of 20 ng 26Al were administered to six animals in each group and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone, liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al were significantly lower in uraemic rats compared to controls, whereas urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/- 6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in uraemia. The target tissues of cellular transferrin-mediated 26Al uptake, liver and spleen, tended to show a larger degree of aluminium accumulation in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27 pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site of extracellular aluminium deposition, 26Al concentrations were more elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g). Estimated total 26Al accumulation in all measured target tissues was significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/- 7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/- 6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our data suggest that fractional absorption from a dietary level dose of 26Al is about 0.13%. Compartmentalization occurs in transferrin-dependent target tissues such as liver and spleen; however, in quantitative terms extracellular deposition in bone is more important. Uraemia has a significant effect on the intestinal absorption and compartmentalization of aluminium. It enhances fractional absorption and increases subsequent extracellular deposition of aluminium in bone. However, at the same time uraemia does not increase transferrin-dependent cellular accumulation of aluminium in liver and spleen.