An enhancer of DNA replication.

cmp, a nucleotide sequence element in the plasmid pT181 of Staphylococcus aureus, acts as an enhancer of DNA replication. When cmp is present on an unrelated vector along with the pT181 origin of replication, it increases the ability of the linked pT181 origin to compete with a coresident pT181 plasmid for the initiator protein RepC. cmp is contained within a 156-base-pair segment, and its deletion from pT181 reduces by twofold the frequency of plasmid replication under derepressed conditions. The enhancer sequence contains a locus of DNA bending, and enhancer activity decreases with distance from the replication origin.     

Circular dichroism of polynucleotides: Interactions of NiCl2 with poly(dA-dT).poly(dA-dT) and poly(dG-dC).poly(dG-dC) in a water-in-oil microemulsion

The thermal behavior of the synthetic, high molecular weight, double stranded polynucleotides poly(dA-dT).poly(dA-dT) [polyAT] and poly(dG-dC).poly(dG-dC) [polyGC] solubilized in the aqueous core of the quaternary water-in-oil cationic microemulsion CTAB|n-pentanol|n-hexane|water in the presence of increasing amounts of NiCl(2) at several constant ionic strength values (NaCl) has been studied by means of circular dichroism and electronic absorption spectroscopies. In the microemulsive medium, both polynucleotides show temperature-induced modifications that markedly vary with both Ni(II) concentration and ionic strength. An increase of temperature causes denaturation of the polyAT duplex at low nickel concentrations, while more complex CD spectral modifications are observed at higher nickel concentrations and ionic strengths. By contrast, thermal denaturation is never observed for polyGC. At low Ni(II) concentrations, the increase of temperature induces conformational transitions from B-DNA to Z-DNA form, or, more precisely, to left-handed helical structures. In some cases, at higher nickel concentrations, the CD spectra suggest the presence of Z'-type forms of the polynucleotide.     

Identification of Insulin in Chick Embryo Retina During Development and Its Inhibitory Effect on DNA Synthesis

Incubation of chick embryo retinal explants with insulin resulted in a pronounced inhibition of thymidine uptake and incorporation into trichloroacetic acid-insoluble fraction. The inhibitory effect was highest with explants from embryos at day 7 and day 8, and thereafter it declined markedly with the age of embryos until day 11. A time-course study of the effect revealed that the inhibition occurred after a lag time; both thymidine uptake and incorporation were not altered significantly after 2-6 h of incubation with insulin, but began to decrease thereafter, reaching the maximum after 16 h. The effect was also dose dependent. After 16 h of incubation, the maximal inhibition (65%) was found with 10(-8) M insulin. Insulin caused similar effects also on thymidine kinase activity. All these effects were obtained by using minimal essential medium without glutamine. The addition of glutamine to the medium reduced the inhibitory effect of insulin. Retinas of chick embryos contain immunoreactive insulin. Retinal immunoreactive insulin was at the highest level (1.12 ng/mg of protein) in the youngest retinas studied (day 6), then it declined with age, reaching the lowest value (0.58 ng/mg of protein) at day 14. This value did not vary significantly during the third week of development. A potential biological role of insulin in retinal development is discussed.     

Glomerular filtration and fluid balance in genetically hypertensive mice

The Schlager genetically hypertensive mouse has been shown to be a valuable animal model with which to study human essential hypertension. Previous studies have characterized renal morphology, juxtaglomerular index, hematocrit, prostaglandin levels, brain catecholamines, social behavior, and patterns of inheritance. The present study continues the phenotypic characterization of this animal model. Using desiccation, isotope dilution, and clearance, the total body water, extracellular fluid volume, and glomerular filtration rate (GFR) in hypertensive and normotensive animals during normal postnatal development were measured. Additionally, using an electron microscopic tracer, the relative permeabilities of the glomerular filter in these animals were assessed. The data indicate a volume expansion in the young hypertensive animals along with a reduction in GFR. As the animals mature the volume expansion in the hypertensives subsides and is eventually reversed resulting in a lower than normal fluid volume level. The significance of the reduced GFR in the hypertensives is also diminished with age although not to the same degree as that of the fluid volume. The indication of a reduced glomerular permeability may account for the above in light of Guyton's cascade hypothesis.     

Addressing long-term physical healthcare needs in a forensic mental health inpatient population using the UK primary care Quality and Outcomes Framework (QOF): an audit

Objectives This audit aims to evaluate the effectiveness of delivering an equivalent primary care service to a long-term forensic psychiatric inpatient population, using the UK primary care national Quality and Outcomes Framework (QOF).Method The audit compares the targets met by the general practitioner with special interest (GPwSI) service, using local and national QOF benchmarks (2005-2006), and determines the prevalence of chronic disease in a long-term inpatient forensic psychiatry population.Results The audit results show that the UK national QOF is a useful tool for assessment and evaluation of physical healthcare needs in a non-community based population. It shows an increased prevalence of all QOF-assessed long-term physical conditions when compared to the local East London population and national UK population, confirming previously reported elevated levels of physical healthcare need in psychiatric populations.Conclusions This audit shows that the UK General Practice QOF can be used as a standardised instrument for commissioning and monitoring the delivery of physical health services to in-patient psychiatric populations, and for the evaluation of the effectiveness of clinical interventions in long-term physical conditions. The audit also demonstrates the effectiveness of using a GPwSI in healthcare delivery in non-community based settings. We suggest that the findings may be generalisable to other long-term inpatient psychiatric and prison populations in order to further the objective of delivering an equivalent primary care service to all populations.The QOF is a set of national primary care audit standards and is freely available on the British Medical Association website or the UK Department of Health website. We suggest that primary care workers in health economies who have not yet developed their own national primary care standards can access and adapt these standards in order to improve the clinical standards of care given to the primary care populations that they serve.