A review of current local dose-area product levels for paediatric fluoroscopy in a tertiary referral centre compared with national standards. Why are they so different?

A prospective single centre study has been performed to assess dose-area product (DAP) values in children having fluoroscopic examinations and to revise local diagnostic reference levels (DRLs). DAP measurements for 2658 examinations performed in a dedicated fluoroscopy room over a period of 21 months were analysed. Data for the eight most commonly performed examinations (2215 cases) are presented.

[Clinical findings of tegumentary leishmaniasis in children under five years of age in an endemic area of Leishmania (Viannia) braziliensis].

A retrospective study was performed in a field clinic to characterize the clinical findings of tegumentary leishmaniasis in children from 0 to 5 years old. The clinical records of 4,464 patients were analyzed at the Primary Health Center of Corte de Pedra, Presidente Tancredo Neves, Bahia, Brazil, from May 1987 to December 1995. Four hundred and ninety one (11.

The reliability of survey assessments of characteristics of medical clinics.

Objective: To assess the reliability of survey measures of organizational characteristics based on reports of single and multiple informants.

Data Source: Survey of 330 informants in 91 medical clinics providing care to HIV-infected persons under Title III of the Ryan White CARE Act.

Study Design: Cross-sectional survey.

Endothelial nitric oxide synthase: insight into cell-specific gene regulation in the vascular endothelium.

The vascular endothelium plays a crucial role in regulating normal blood vessel physiology. The gene products responsible are commonly expressed exclusively, or preferentially, in this cell type. However, despite the importance of regulated gene expression in the vascular endothelium, relatively little is known about the mechanisms that restrict endothelial-specific gene expression to this cell type.

Tyrosine phosphatase MEG2 modulates murine development and platelet and lymphocyte activation through secretory vesicle function.

MEG2, a protein tyrosine phosphatase with a unique NH2-terminal lipid-binding domain, binds to and is modulated by the polyphosphoinositides PI(4,5)P2 and PI(3,4,5)P3. Recent data implicate MEG2 in vesicle fusion events in leukocytes. Through the genesis of Meg2-deficient mice, we demonstrate that Meg2-/- embryos manifest hemorrhages, neural tube defects including exencephaly and meningomyeloceles, cerebral infarctions, abnormal bone development, and >90% late embryonic lethality.

Quality of HIV care provided by nurse practitioners, physician assistants, and physicians.

Background: Nurse practitioners (NPs) and physician assistants (PAs) are primary care providers for patients with HIV in some clinics, but little is known about the quality of care that they provide.

Objective: To compare the quality of care provided by NPs and PAs with that provided by physicians.

Design: Cross-sectional analysis.

Hypoxia induces a functionally significant and translationally efficient neuronal NO synthase mRNA variant.

We tested the hypothesis that induction of neuronal NO synthase (nNOS) impairs vascular smooth muscle contractility after hypoxia. nNOS protein was increased in aorta, mesenteric arterioles, pulmonary arteries, brain, and diaphragm from rats exposed to 8% O2 for 48 hours and in human aortic SMCs after hypoxic incubation (1% O2). Ca-dependent NO synthase activity was increased in endothelium-denuded aortic segments from hypoxia-exposed rats.

Correlations of regional cerebral metabolism with memory performance and executive function in patients with herpes encephalitis or frontal lobe lesions.

Cerebral [18F]fluorodeoxyglucose positron emission tomography (18FDG-PET) data from patients suffering amnesia following herpes encephalitis (n=7) or frontal lobe pathology (n=14) were compared with data from age-matched nonamnesic subjects (n=10). All subjects received structural MRI, resting 18FDG-PET scans, and neuropsychological evaluation. PET data were analyzed using complementary statistical parametric mapping and region-of-interest methods.

Epigenetic basis for the transcriptional hyporesponsiveness of the human inducible nitric oxide synthase gene in vascular endothelial cells.

A marked difference exists in the inducibility of inducible NO synthase (iNOS) between humans and rodents. Although important cis and trans factors in the murine and human iNOS promoters have been characterized using episomal-based approaches, a compelling molecular explanation for why human iNOS is resistant to induction has not been reported. In this study we present evidence that the hyporesponsiveness of the human iNOS promoter is based in part on epigenetic silencing, specifically hypermethylation of CpG dinucleotides and histone H3 lysine 9 methylation.

Differential changes in brain glucose metabolism during hypoglycaemia accompany loss of hypoglycaemia awareness in men with type 1 diabetes mellitus. An [11C]-3-O-methyl-D-glucose PET study.

Aims/hypothesis: Hypoglycaemia unawareness in type 1 diabetes increases the risk of severe hypoglycaemia and impairs quality of life for people with diabetes. To explore the central mechanisms of hypoglycaemia awareness, we used [11C]-3-O-methyl-D-glucose (CMG) positron emission tomography (PET) to measure changes in global and regional brain glucose metabolism between euglycaemia and hypoglycaemia in aware and unaware diabetic subjects.

Materials And Methods: Twelve men with type 1 diabetes, of whom six were characterised as aware and six as unaware of hypoglycaemia, underwent two CMG-PET brain scans while plasma glucose was controlled by insulin and glucose infusion either at euglycaemia (5 mmol/l) or at hypoglycaemia (2.

Extensive variation in the 5'-UTR of Dicer mRNAs influences translational efficiency.

The Dicer enzyme is a key component of the RNA interference pathway and also responsible for the processing of micro RNAs, non-coding RNA molecules which regulate the activity of mRNAs by antisense base pairing. Little is known about the structure and regulation of human Dicer mRNA. A comprehensive characterization of Dicer 5'-untranslated region (5'-UTR) RNA structure revealed important diversity within human Dicer mRNA transcripts.

Targeted deletion of Fgl-2/fibroleukin in the donor modulates immunologic response and acute vascular rejection in cardiac xenografts.

Background: Xenografts ultimately fail as a result of acute vascular rejection (AVR), a process characterized by intravascular thrombosis, fibrin deposition, and endothelial cell activation.

Methods And Results: We studied whether targeted deletion of Fgl-2, an inducible endothelial cell procoagulant, (Fgl-2-/-) in the donor prevents AVR in a mouse-to-rat cardiac xenotransplantation model. By 3 days after transplant, Fgl-2+/+ grafts developed typical features of AVR associated with increased levels of donor Fgl-2 mRNA.

Cloning and characterization of the human CD200 promoter region.

CD200 is a type I membrane glycoprotein which is expressed on a number of cell types uniquely relevant to the inflammatory and immune cascade; included in those are dendritic cells, endothelial cells and activated T cells. Previous studies have shown that CD200 plays an important role in prevention of graft rejection, autoimmune diseases and spontaneous abortion. The molecular mechanism(s) controlling expression of CD200 are yet to be defined.

Physician specialization and the quality of care for human immunodeficiency virus infection.

Background: There is debate over the types of physicians who should treat patients with complex chronic medical conditions such as human immunodeficiency virus (HIV) infection. We sought to assess the relationship between specialty training and expertise and the quality of care delivered to patients with HIV infection.

Methods: We selected random samples of HIV-infected patients receiving care at 64 Ryan White CARE (Comprehensive AIDS Resources Emergency) Act-funded clinics throughout the country and their primary HIV physicians for an observational cohort study in which quality-of-care measures were assessed by medical record review.

The expression of endothelial nitric-oxide synthase is controlled by a cell-specific histone code.

Expression of endothelial nitric-oxide synthase (eNOS) mRNA is highly restricted to the endothelial cell layer of medium to large sized arterial blood vessels. Here we assessed the chromatin environment of the eNOS gene in expressing and nonexpressing cell types. Within endothelial cells, but not a variety of nonendothelial cells, the nucleosomes that encompassed the eNOS core promoter and proximal downstream coding regions were highly enriched in acetylated histones H3 and H4 and methylated lysine 4 of histone H3.

Glutathione depletion inhibits lipopolysaccharide-induced intercellular adhesion molecule 1 synthesis.

Cellular redox status is known to regulate a number of biological processes, including the activation of inflammatory genes. Our previous studies demonstrated that thiol depletion using diethyl maleate (DEM) reduced neutrophil sequestration in animal models of inflammation, an effect primarily mediated by impaired upregulation of the adhesion molecule, ICAM-1. The present studies were performed to discern the mechanism whereby DEM prevents LPS-induced ICAM-1 expression in human umbilical vein endothelial cells.

Predicting protein-ligand binding affinities: a low scoring game?

We have investigated the performance of five well known scoring functions in predicting the binding affinities of a diverse set of 205 protein-ligand complexes with known experimental binding constants, and also on subsets of mutually similar complexes. We have found that the overall performance of the scoring functions on the diverse set is disappointing, with none of the functions achieving r(2) values above 0.32 on the whole dataset.

Dissociation between global markers of bone formation and direct measurement of spinal bone formation in osteoporosis.

Unlabelled: Regional bone metabolism measured using 18F-fluoride PET was assessed in 72 postmenopausal women classified as normal, osteopenic, or osteoporotic. Lower values of regional bone formation activity at the lumbar spine were seen in osteoporotic women, whereas global markers of bone formation were significantly increased.

Introduction: Evaluations of global bone remodeling have revealed that increased bone turnover is a feature of patients with osteoporosis.

Differences in patient and clinic characteristics at CARE Act funded versus non-CARE Act funded HIV clinics.

The Ryan White CARE Act supports comprehensive care to persons with HIV infection. With an annual budget of over $1 billion, it is the largest federally funded programme for HIV care in the USA. We analysed data from the HIV Costs and Services Utilization Study, a nationally representative sample of HIV patients.

Structural and functional heterogeneity in the CD200R family of immunoregulatory molecules and their expression at the feto-maternal interface.

Problem: We have shown that CD200Fc, a chimeric molecule including the extracellular domain of CD200 and a murine immunoglobulin (Ig)G2a Fc region, regulates immune responses and prevents T helper (Th)1 cytokine-triggered spontaneous abortions in mice. CD200 is expressed on a subpopulation of uterine decidua cells and on trophoblast, both in the mouse and human. The receptor(s) for CD200, CD200R(s), was not previously well-characterized.

Bright, single-spatial-mode source of frequency non-degenerate, polarization-entangled photon pairs using periodically poled KTP.

We use two perpendicular crystals of periodically-poled KTP to directly generate polarization-entangled photon pairs, the majority of which are emitted into a single Gaussian spatial mode. The signal and idler photons have wavelengths of 810 nm and 1550 nm, respectively, and the photon-pair generation rate is 1.2x107 sec-1 for a pump power of 62 mW.

Post-transcriptional regulation of endothelial nitric-oxide synthase by an overlapping antisense mRNA transcript.

Endothelial nitric-oxide synthase (eNOS) mRNA levels are abnormal in diseases of the cardiovascular system, but changes in gene expression cannot be accounted for by transcription alone. We found evidence for the existence of an antisense mRNA (sONE) that is derived from a transcription unit (NOS3AS) on the opposite DNA strand from which the human eNOS (NOS3) mRNA is transcribed at human chromosome 7q36. The genes are oriented in a tail-to-tail configuration, and the mRNAs encoding sONE and eNOS are complementary for 662 nucleotides.

CD200 is a ligand for all members of the CD200R family of immunoregulatory molecules.

CD200Fc, a chimeric molecule including the extracellular domain of CD200 and a murine IgG2a Fc region, regulates immune responses following engagement of a cell surface receptor, CD200R, expressed on cells of the myeloid and T cell lineage. A recent report focused attention on a family of CD200Rs, but concluded that only one member used CD200 as its ligand. We have also cloned and sequenced a family of CD200Rs, but identify an amino terminus to two of the three isoforms not recognized by previous researchers.