Rapid tests and urine sampling techniques for the diagnosis of urinary tract infection (UTI) in children under five years: a systematic review

Background: Urinary tract infection (UTI) is one of the most common sources of infection in children under five. Prompt diagnosis and treatment is important to reduce the risk of renal scarring. Rapid, cost-effective, methods of UTI diagnosis are required as an alternative to culture. Methods: We conducted a systematic review to determine the diagnostic accuracy of rapid tests for detecting UTI in children under five years of age. Results: The evidence supports the use of dipstick positive for both leukocyte esterase and nitrite (pooled LR+ = 28.2, 95% CI: 17.3, 46.0) or microscopy positive for both pyuria and bacteriuria (pooled LR+ = 37.0, 95% CI: 11.0, 125.9) to rule in UTI. Similarly dipstick negative for both LE and nitrite (Pooled LR- = 0.20, 95% CI: 0.16, 0.26) or microscopy negative for both pyuria and bacteriuria (Pooled LR- = 0.11, 95% CI: 0.05, 0.23) can be used to rule out UTI. A test for glucose showed promise in potty-trained children. However, all studies were over 30 years old. Further evaluation of this test may be useful. Conclusion: Dipstick negative for both LE and nitrite or microscopic analysis negative for both pyuria and bacteriuria of a clean voided urine, bag, or nappy/pad specimen may reasonably be used to rule out UTI. These patients can then reasonably be excluded from further investigation, without the need for confirmatory culture. Similarly, combinations of positive tests could be used to rule in UTI, and trigger further investigation

How does study quality affect the results of a diagnostic meta-analysis?

Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited

Molecular pathways leading to loss of skeletal muscle mass in cancer cachexia can findings from animal models be translated to humans?

Background: Cachexia is a multi-factorial, systemic syndrome that especially affects patients with cancer of the gastrointestinal tract, and leads to reduced treatment response, survival and quality of life. The most important clinical feature of cachexia is the excessive wasting of skeletal muscle mass. Currently, an effective treatment is still lacking and the search for therapeutic targets continues. Even though a substantial number of animal studies have contributed to a better understanding of the underlying mechanisms of the loss of skeletal muscle mass, subsequent clinical trials of potential new drugs have not yet yielded any effective treatment for cancer cachexia. Therefore, we questioned to which degree findings from animal studies can be translated to humans in clinical practice and research. Discussion: A substantial amount of animal studies on the molecular mechanisms of muscle wasting in cancer cachexia has been conducted in recent years. This extensive review of the literature showed that most of their observations could not be consistently reproduced in studies on human skeletal muscle samples. However, studies on human material are scarce and limited in patient numbers and homogeneity. Therefore, their results have to be interpreted critically. Summary: More research is needed on human tissue samples to clarify the signaling pathways that lead to skeletal muscle loss, and to confirm pre-selected drug targets from animal models in clinical trials. In addition, improved diagnostic tools and standardized clinical criteria for cancer cachexia are needed to conduct standardized, randomized controlled trials of potential drug candidates in the future

Cold Climate is an Important Factor in Explaining Regional Differences in Coronary Mortality Even if Serum Cholesterol and other Established Risk Factors are Taken into Account

Earlier studies have shown a strong regional association between cold climate and coronary mortality in Sweden and that coronary mortality is more strongly associated with cold climate than with other explanatory factors such as drinking water hardness, socioeconomic factors, tobacco and sales of butter. To examine the joint impact of these factors and to investigate regional differences in serum cholesterol and their relation to cold climate and coronary mortality, regression analyses were performed with 259 municipalities in Sweden as units. Mortality from acute myocardial infarction in men aged 40–64 during 1975–1984 was used as the dependent variable. A cold index was calculated, this index and the above mentioned factors were used as explanatory variables. The main results were: Cold index was the strongest factor when introduced into a multiple regression model. Four other strong factors had to be used to obtain the same explanatory strength as cold index did alone, and even when introduced as the last factor, cold index increased the coefficient of determination substantially. In a subsample of 37 municipalities, serum cholesterol was not significantly associated with coronary mortality. However, there was a significant correlation between cold index and serum cholesterol. </jats:p

Improvement of the plasma lipoprotein pattern after institution of insulin treatment in diabetes mellitus

Plasma lipids and lipoproteins were studied in 26 nonobese diabetic patients, either newly diagnosed or unsatisfactorily controlled by oral antidiabetic treatment. Measurements were performed before and 3-4 mo after the institution of insulin treatment. In a subgroup of seven patients, the activities of lipoprotein lipase (LPL) and hepatic lipase (HL) in postheparin plasma and the elimination rate of exogenous triglyceride were also monitored. After beginning insulin treatment, diabetic control was improved as demonstrated by decreasing levels of HbA1. Mean plasma cholesterol and triglyceride levels decreased by about 10% (P less than 0.01) and 40% (P less than 0.05), respectively. The decrease in plasma cholesterol was largely accounted for by a fall in LDL cholesterol levels (-8%, P less than 0.05), while plasma HDL cholesterol concentrations increased by about 12% (P less than 0.01). The elimination rate of exogenous triglycerides increased significantly. There was a suggestive, but not significant, increase in LPL activity while the HL activity remained unchanged. It is concluded that the improved diabetic control after institution of insulin treatment results in a significant improvement of the plasma lipoprotein profile. Since the improvement of the lipoprotein pattern is not strictly correlated to the amelioration of indices reflecting glucose transport, we suggest that the plasma lipoprotein pattern may provide an additional tool for monitoring the degree of control in diabetes mellitus

Smoking Habits, Sales of Fat and Antihypertensives Fail to Explain the High Coronary Mortality in Cold Regions of Sweden

A previous study has shown a strong regional association between cold climate and coronary mortality in Sweden. The present study intended to elucidate further this association, in particular whether or not it could be attributed to smoking, hypertension and fat consumption. The 284 Swedish municipalities were used as units. The outcome was mortality (SMR) from acute myocardial infarction in men aged 40–64. Prevalence of smoking and use of snuff was estimated by interviews. Sales of antihypertensive drugs were used to estimate prevalence of hypertension. Sales of butter and estimates of consumption of saturated fat by interviews were used to estimate the consumption of fat. Weighted determination coefficients (D) were calculated. Apart from the strong association between cold climate and coronary mortality (D=0.39), an association was shown between fat consumption and coronary mortality (D=0.22). A weaker association was found between prevalency of snuffing and coronary mortality (D=0.15) and between sales of butter and coronary mortality (D=0.10) and the weakest between sales of antihypertensives and coronary mortality (D=0.06). No association was found between prevalence of smoking and coronary mortality. When the other explanatory factors were added to cold climate in the model no substantial enhancement of the association was achieved. Cold exposure was correlated to the other explanatory factors. To conclude, this study showed that the strong association between cold exposure and coronary mortality was not affected by the regional variation in the estimates of fat consumption, hypertension or tobacco use. </jats:p

Purine metabolic pathways in rat hindlimb perfusion model during ischemia and reperfusion

The perfused rat hindlimb preparation was used with a blood cell-free perfusate to investigate alterations in the purine nucleotide metabolism, flow rate, perfusion pressure, and venous excretion in response to ischemia and ischemia followed by reperfusion in skeletal muscle. The development of a physical hindrance during postischemic reperfusion, indicated by an increase in reperfusion pressure and a decrease in flow rate, coincided with a 90% decrease in phosphocreatine and a 50-70% reduction in total adenine nucleotide pool. The reflow impairment could not be explained by blood cell plugging of the capillaries. Washout of several metabolites was demonstrated during reperfusion. Hypoxanthine accumulated intracellularly during ischemia, and a substantial amount of uric acid was excreted into the venous effluent during reperfusion. The experimental data were fitted into a computer simulation model of the purine pathways. The model indicated that AMP deaminase was the predominant enzymatic pathway for the AMP degradation. It was demonstrated that ATP preferably accumulated as inosine-5'-monophosphate during ischemia and that xanthine oxidase was undetectable in skeletal muscle tissue homogenates. However, vascular endothelial cell xanthine oxidase activity responsible for a free radical-induced reperfusion injury could not be excluded. </jats:p