Quantitative reverse transcriptase PCR (RT-PCR) is a sensitive method for the measurement of mRNA copy number. However, the methodology has gained a reputation for poor reproducibility, leading to concern over the validity of much of the data generated using this technique. We have developed two variants of quantitative competitive RT-PCR using a synthesized RNA as an internal standard to measure precisely the relative levels of alpha-, beta- and gamma-fibrinogen mRNAs in the four lobes of the rat liver. In the first of these variants we altered only the amount of total RNA in the RT-PCR reaction, keeping the amount of internal standard RNA and the number of PCR cycles constant. In the second variant only the number of PCR cycles was altered, and the amounts of total RNA and standard RNA were kept constant. Both variants of RT-PCR allowed calculation of the number of mRNA copies, which did not differ significantly between the two techniques. Of the two variants, the second gave better reproducibility, and the intra-assay coefficient of variation for this technique was 14% (n = 20). Using these two variants we have shown that there are different numbers of fibrinogen mRNAs in the four liver lobes for each of the three genes (alpha-fibrinogen F = 14.64, P = 0.0003; beta-fibrinogen F = 3.74, P = 0.04; gamma-fibrinogen F = 3.75, P = 0.04). In conclusion, by using two variants of quantitative competitive RT-PCR we have shown that this technique can be used to give reproducible results, and the low intra-assay coefficient of variation suggests that quantitative RT-PCR should be the technique of choice for accurate measurement of mRNA copy number.
The mechanism by which maternal Fe deficiency in the rat causes fetal growth retardation has not been clearly established. This study compared the effects on the fetuses from dams fed a control diet with two groups of dams fed Fe-restricted diets. One Fe-restricted group was fed the Fe-restricted diet for 1 week prior to mating and throughout gestation and the second Fe-restricted group was fed the Fe-restricted diet for 2 weeks prior to mating and throughout gestation. On day 21 of gestation Fe-restricted dams, and their fetuses, were anaemic. Fetal weight was reduced in both Fe-restricted groups compared with controls. Expression of hypoxia-inducible factor (HIF)-1alpha and vascular endothelial growth factor (VEGF) are induced by hypoxia. The levels of HIF-1alpha mRNA were highest in placenta, then in kidney, heart and liver but were not different between the groups. Levels of plasma VEGF were not different between the groups. Maternal plasma triacylglycerol was decreased in the 1-week Fe-restricted dams compared with controls. Maternal plasma cholesterol and free fatty acid levels were not different between the groups. In fetal plasma, levels of triacylglycerol and cholesterol were decreased in both Fe-restricted groups. In maternal plasma, levels of a number of amino acids were elevated in both Fe-restricted groups. In contrast, levels of a number of amino acids in fetal plasma were lower in both Fe-restricted groups. Fetal plasma lactate was increased in Fe-restricted fetuses but fetal plasma glucose and beta-hydroxybutyrate were not affected. These changes in fetal metabolism may contribute to fetal growth retardation in this model. This study does not support the hypothesis that the Fe-restricted fetus is hypoxic.
This retrospective study investigated the demographics and treatment outcomes of patients with cellulitis receiving outpatient parenteral antibiotic therapy (OPAT) between 2010 and 2014 in Cambridge University Hospitals. The rate of treatment failure (as indicated by the readmission to hospital) was low, at 5.5%. Risk factors associated with a longer duration of OPAT treatment included: immunosuppression, peripheral vascular disease, obesity, lymphoedema, previous cellulitis and diabetes.
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