Evaluation of an in-line dialysate urea monitor including assessment of 'V'

Summary: Dialysate based assessment of the delivered dose of dialysis offers several advantages over blood sampling methods as it remains accurate in the face of fistula recirculation, urea rebound, variable blood flow and incorrect treatment time. Kr/V is calculated from the slope of the decline in urea concentration in the dialysate over the course of the treatment. By equilibrating dialysate with blood at the initiation of the treatment an estimate of pre-dialysis blood urea and the volume of distribution for urea (V) can be obtained. We performed Kt/V assessments on 20 in-centre haemodialysis patients using the Baxter Biostat 1000® dialysate urea monitor and compared the results with urea reduction ratios and Kt/V calculated by the formula of Basile. In addition, in 11 of these patients, V and pre-dialysis urea was derived and compared to total body water estimates using D₂O. the mean Kt/V by Biostat was 1.11 ± 0.23 and by formula was 1.23 ± 0.16 ( P < 0.005, Student's paired t -test). the lab pre-dialysis urea was 24.4 ± 6.2 mmol/L compared to the Biostat result of 23.9 ± 5.9 (when corrected for plasma water), with the mean difference of the techniques being −0.53 mmol/L. (95% CI −0.36–1.42). For V, the D₂O result was 36.7 ± 9.7 litres, compared to the Biostat result of 37.9 ± 9.6. the mean difference of the techniques by Bland and Altman analysis (or bias of the Biostat) was 1.2 L (95% CI −0.9–3.3) and the limits of agreement were −5.2–7.6L. Thus the Biostat provides easy access to dialysis adequacy data and gives a reasonable assessment of V, tending to overestimate this value.     

Identification of personality types at risk for poor health and injury in late adolescence

In an unselected general birth cohort of 862 18-year-olds, we sought to identify the personality characteristics associated with involvement in each of five different health-risk behaviours (unprotected sexual intercourse with multiple partners, dangerous driving habits, violent crime, alcohol dependence and marijuana dependence) as well as the personality characteristics associated with a syndrome of multiple health-risk behaviours. A unique configuration of traits differentiated youth involved in any given single health-risk behaviour from youth who were not. These youth were more impulsive, aggressive, alienated and tended to experience negative emotions in response to daily hassles. A different unique configuration of traits differentiated youth involved in a syndrome of multiple health-risk behaviours from youth involved in a single or in no health-risk behaviours. These youth were distinguished by a rejection of social norms, danger-seeking, impulsivity, a very low threshold for negative emotional responses such as anger, irritability and nervous tension, and by little need or capacity for connection to other people. In planning health campaigns, health professionals need to consider the unique psychological make-up of persons most at risk for health-risk behaviours and design programmes that will appeal to them.     

Evaluation of a new technique for the demonstration of gonococci and other micro-organisms in host cells.

A method (Gram-MGPLG) for demonstrating micro-organisms was compared with Gram and four other known methods. Each method was tested on tissue infected with Staphylococcus aureus, Pseudomonas aeruginosa or Neisseria gonorrhoeae, which were then fixed in Bouin's formol saline, formol sublimate, or Van de Grift solutions. Gram-positive organisms in tissues were easily seen even at low magnification when stained by several of the methods tested. Gram-negative organisms, however, are very difficult to locate when stained by Gram's method because tissue components and the organisms are all shades of red, whereas the Gram-MGPLG provided easier location of organisms because these are stained red while the nuclei are blue and connective tissue is green. All methods are markedly affected by fixation; better preservation of cytological detail and improved staining reactions were produced by fixative containing mercuric chloride.     

A seven year follow-up study of the cognitive development of children who experienced common perinatal problems

The prevalence of perinatal problems in a sample of 1037 children was described. There was no significant association between perinatal problems and socio-economic status. The association between perinatal problems and cognitive development was examined by stepwise regression analyses of the more common perinatal problems on cognitive factor scores, using measures of language and, intelligence taken when the children were aged 3, 5, and 7 years. Of 14 perinatal problems analysed in this manner, only two, being a twin or being small for gestational age, were found to be consistently associated with a significantly lower cognitive factor score.     

A 6 year follow-up of childhood enuresis: Prevalence in adolescence and consequences for mental health

Recent studies have shown an association between enuresis and behavioural or emotional problems. The direction or causality of the association and its duration, however, remain unclear. This study followed a large group of children from ages 11 to 15 years and reported the prevalence of enuresis to age 13 years. The enuretic status of the sample at age 11 years was established relative to the history of enuresis at age 9 years. At age 11 years a significant association was found between enuresis and measures of psychopathology. This association was particularly evident for those children with secondary enuresis, and those who had a history of enuresis but had ceased to wet the bed. Current primary enuresis was not significantly associated with disorder. Similar associations were found between enuresis at age 11 and later disorder at age 13. At age 15 years no significant associations between enuresis and disorder were found. These findings have implications for parents of children with enuresis and for clinicians dealing with the disorder.     

A longitudinal study of reasons for smoking in adolescence

This longitudinal study examined factors related to smoking at age 13 and to persistence of smoking from ages 13 to 15 years in a sample (n =719) of New Zealand adolescents. History of smoking at 9 and 11 years predicted smoking at 13 (odds ratio = 2.8), persistence of smoking from age 13 to 15 (OR = 2.4) and smoking at 15 among those not smoking at age 13 (OR = 2.4). While there were no significant sex differences in pre-adolescent and early adolescent smoking, by age 15 more girls than boys reported smoking. A concern with the immediate negative effects of smoking (taste, smell, feeling ill and feeling silly) as a reason for not smoking at age 13 was inversely related to smoking at age 15 (OR = 0.4). Reasons for smoking at age 13 were not associated with later smoking. Family disadvantage and use of alcohol and other drugs were also associated with later adolescent smoking.