An Electronic Data Capture Framework (ConnEDCt) for Global and Public Health Research: Design and Implementation

Background

When we were unable to identify an electronic data capture (EDC) package that supported our requirements for clinical research in resource-limited regions, we set out to build our own reusable EDC framework. We needed to capture data when offline, synchronize data on demand, and enforce strict eligibility requirements and complex longitudinal protocols. Based on previous experience, the geographical areas in which we conduct our research often have unreliable, slow internet access that would make web-based EDC platforms impractical. We were unwilling to fall back on paper-based data capture as we wanted other benefits of EDC. Therefore, we decided to build our own reusable software platform. In this paper, we describe our customizable EDC framework and highlight how we have used it in our ongoing surveillance programs, clinic-based cross-sectional studies, and randomized controlled trials (RCTs) in various settings in India and Ecuador.

Objective

This paper describes the creation of a mobile framework to support complex clinical research protocols in a variety of settings including clinical, surveillance, and RCTs.

Methods

We developed ConnEDCt, a mobile EDC framework for iOS devices and personal computers, using Claris FileMaker software for electronic data capture and data storage.

Results

ConnEDCt was tested in the field in our clinical, surveillance, and clinical trial research contexts in India and Ecuador and continuously refined for ease of use and optimization, including specific user roles; simultaneous synchronization across multiple locations; complex randomization schemes and informed consent processes; and collecting diverse types of data (laboratory, growth measurements, sociodemographic, health history, dietary recall and feeding practices, environmental exposures, and biological specimen collection).

Conclusions

ConnEDCt is customizable, with regulatory-compliant security, data synchronization, and other useful features for data collection in a variety of settings and study designs. Furthermore, ConnEDCt is user friendly and lowers the risks for errors in data entry because of real time error checking and protocol enforcement.

Repair of oesophageal atresia by consultants and supervised trainees results in similar outcomes

INTRODUCTION

Consultants and trainees require exposure to complex cases for maintaining and gaining operative experience. Oesophageal atresia (OA) repair is a neonatal surgical procedure with indicative numbers for completion of training. A conflict of interest may exist between adequate training, maintaining consultant experience and achieving good outcomes. We aimed to review outcomes of procedures performed primarily by trainees and those performed by consultants.

METHODS

We carried out a retrospective case note review of all consecutive infants who underwent surgical repair of OA with distal tracheooesophageal fistula (TOF) between January 1994 and December 2014 at our institution. Only cases that underwent primary oesophageal anastomosis were included. Surgical outcomes were compared between cases that had a trainee and those that had a consultant listed as the primary operator.

RESULTS

One hundred and twenty-two cases were included. A total of 52 procedures were performed by trainees, and 68 by consultants. Two cases were undeterminable and excluded. Infant demographics, clinical characteristics and duration of follow-up were similar between groups. All infants survived to discharge. Procedures performed by trainees and those performed by consultants as primary operators had a similar incidence of postoperative pneumothorax (trainees 4, consultants 3; p=0.46), anastomotic leak (trainees 5, consultants 3; p=0.29) and recurrent TOF (trainees 0, consultants 2; p=0.5). Overall 52% of cases had an anastomotic dilatation during follow-up, with no difference between the trainee and consultant groups (50% vs 53%; p=0.85).

CONCLUSIONS

Surgical outcomes for repair of OA/TOF are not adversely affected by trainee operating. Trainees with appropriate skills should perform supervised OA/TOF repair. These data are important for understanding the interrelationship between provision of training and surgical outcomes.

Improving paediatric antimicrobial stewardship in hospital-based settings: why, where and how?

Background

Antimicrobial resistance (AMR) is being recognized as a priority by healthcare organizations across the world. However, many children are managed on IV antimicrobials in hospital with very little consideration of antimicrobial stewardship issues.

Objectives

A nurse-led paediatric ambulatory outpatient parenteral antimicrobial therapy (OPAT) service, managing children with common infections being ambulated on short courses of IV antimicrobials, was introduced within Southampton Children’s Hospital in January 2018. We evaluated the impact of this service in terms of the quality of antimicrobial prescribing and timing of ambulation in children presenting with common infections.

Methods

All cases managed within the service were reviewed in two separate 2 month time periods: prior to introduction of the service (September–October 2016) and then prospectively after its introduction (September–October 2018).

Results

A total of 96% of IV antibiotic management decisions at 48 h were deemed appropriate in 2018, compared with 75% in 2016. A total of 64% of patients were ambulated on IV antibiotics at some point during their treatment course in 2018, compared with 19% in 2016. However, a significant proportion of antimicrobial decisions made at the point of presentation to hospital remained suboptimal in 2018.

Conclusions

Children are commonly managed with IV antibiotics in hospital. We demonstrate marked improvements in appropriate antimicrobial use through the introduction of a nurse-led ambulatory OPAT service. In addition, such a service can promote a greater proportion of children being ambulated from hospital, freeing up valuable inpatient beds and potentially delivering cost savings that can be used to fund such services.

The Concise Guide to PHARMACOLOGY 2013/14: overview

The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.

The atmospheric chemistry of trace gases and particulate matter emitted by different land uses in Borneo

We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity.

Survey of fungi and yeast in polymicrobial infections in chronic wounds

OBJECTIVE

To assess the incidence, abundance and species diversity of fungi in chronic wounds, as well as to describe the associations of major fungi populations.

METHOD

Comprehensive molecular diagnostic reports were evaluated from a total of 915 chronic wounds in a retrospective study.

RESULTS

Of the 915 clinical specimens, 208 (23%) were positive for fungal species. These samples were further compared in a compiled dataset, and sub-classified among the four major chronic wound types (decubitus ulcer, diabetic foot ulcer, non-healing surgical wound, and venous leg ulcer). The most abundant fungi were yeasts in the genus Candida; however, Curvularia, Malessezia, Aureobasidium, Cladosporium, Ulocladium, Engodontium and Trichtophyton were also found to be prevalent components of these polymicrobial infections. A notable bacterial/fungal negative correlation was found to be apparent between Staphylococcus and Candida. There were also significant relationships between both bacterial and fungal genera and patient metadata including gender, diabetes status and cardiovascular comorbidities.

CONCLUSION

This microbial survey shows that fungi are more important wound pathogens and opportunistic pathogens than previously reported, exemplifying the impact of these under-reported pathogens. With the application of modern cost-effective and comprehensive molecular diagnostics, clinicians can now identify and address this significant component of chronic wound bioburden with targeted therapies, thereby improving healing trajectories.

Methylation profiling of rectal cancer identifies novel markers of early-stage disease

BACKGROUND

Radical surgery is the de facto treatment for early rectal cancer. Conservative surgery with transanal endoscopic microsurgery can achieve high rates of cure but the histopathological measures of outcome used to select local treatment lack precision. Biomarkers associated with disease progression, particularly mesorectal nodal metastasis, are urgently required. The aim was to compare patterns of gene-specific hypermethylation in radically excised rectal cancers with histopathological stage.

METHODS

Locus-specific hypermethylation of 24 tumour suppressor genes was measured in 105 rectal specimens (51 radically excised adenocarcinomas, 35 tissues adjacent to tumour and 19 normal controls) using the methylation-specific multiplex ligation-dependent probe assay (MS-MLPA). Methylation values were correlated with histopathological indices of disease progression and validated using bisulphite pyrosequencing.

RESULTS

Five sites (ESR1, CDH13, CHFR, APC and RARB) were significantly hypermethylated in cancer compared with adjacent tissue and normal controls (P < 0·050). Methylation at these sites was higher in Dukes' A than Dukes' 'D' cancers (P = 0·013). Methylation at two sites (GSTP1 and RARB) was individually associated with localized disease (N0 and M0 respectively; P = 0·006 and P = 0·008). Hypermethylation of at least two of APC, RARB, TIMP3, CASP8 and GSTP1 was associated with early (N0 M0) disease (N0, P = 0·002; M0, P = 0·044). Methylation levels detected by MS-MLPA and pyrosequencing were concordant.

CONCLUSION

Locus-specific hypermethylation was more prevalent in early- than late-stage disease. Hypermethylation of two or more of a panel of five tumour suppressor genes was associated with localized disease.

Effects of biofilm treatments on the multi-species Lubbock chronic wound biofilm model

OBJECTIVE

To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in vitro multi-species chronic wound biofilm model.

METHOD

The Lubbock Chronic Wound Biofilm (LCWB) model has been described in detail elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two proprietary, semi-solid, wound-dressing formulations currently under development (Sanguitec gels).

RESULTS

Biofilm formation was completely inhibited in the LCWB model following treatment with 20% xylitol, 10% erythritol, 1,000 microg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two Sanguitec gel formulations. Salicylic acid specifically inhibited S. aureus (p<0.01) at 10mM and 20mM, consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations. The inhibitory effect of both Sanguitec gel formulations was more broadly effective, with an increasingly inhibitory effect on all LCWB species (p<0.01).

CONCLUSION

The LCWB model provides a multi-species format with which to evaluate the effect of biofilm effectors on wound flora in a biofilm phenotype. These results suggest that different treatments can target specific populations within a biofilm. Salicylic acid preferentially targeted S. aureus, xylitol preferentially targeted P. aeruginosa, while erythritol preferentially targeted both P. aeruginosa and S. aureus. In contrast, the two Sanguitec gel formulations provided a broad, less preferential, inhibition of biofilm development.

DECLARATION OF INTEREST

Research and Testing Laboratory is a for-profit enterprise that develops molecular methods and performs service research work on biofilms. Sanguitec gel was developed by JPK and CEJ.

Allelic diversity within the high frequency Mamu-A2*05/Mane-A2*05 (Mane-A*06)/Mafa-A2*05 family of macaque MHC-A loci

Macaque species serve as important animal models of human infection and immunity. To more fully scrutinize their potential in both the analysis of disease pathogenesis and vaccine development, it is necessary to characterize the major histocompatibility complex (MHC) class I loci of Macaca mulatta (Mamu), Macaca nemestrina (Mane), and Macaca fascicularis (Mafa) at the genomic level. The oligomorphic Mamu-A2*05/Mane-A2*05 (previously known as Mane-A*06) family of macaque MHC-A alleles has recently been shown to be present at high frequency in both Indian rhesus and pig-tailed macaque populations. Using a locus-specific amplification and direct DNA typing methodology, we have additionally found that the locus encoding this family is very prevalent (75%) among a sampling of 182 Chinese rhesus macaques and has a high prevalence (80%) within a larger, independent cohort of 309 pig-tailed macaques. Interestingly, among the Chinese rhesus macaques, only six alleles previously identified in Indian-origin animals were observed, while three recently identified in Chinese-origin animals and 25 new alleles were characterized. Among the pig-tailed macaques, we observed 1 previously known (Mane-A*06) and 19 new alleles. Examination of the orthologous locus in a preliminary sampling of 30 cynomolgus macaques showed an even higher presence (87%) of Mafa-A2*05 family alleles, with 5 previously identified and 15 new alleles characterized. The continued discovery of novel alleles and thus further diversity within the Mamu-A2*05/Mane-A2*05/Mafa-A2*05 family indicates that this MHC-A locus, although highly conserved across the three species of macaques, has remained a dynamic entity during evolution.

Anion photoelectron spectroscopy and density functional investigation of diniobium-carbon clusters

Experimental photoelectron and computational results show diniobium-carbon (Nb(2)C(n)) clusters to coexist in multiple structural isomers: three-dimensional geometries, planar rings, and linear chains. Three-dimensional clusters having up to five carbons are formed preferentially with Nb-Nb bonding, whereas only Nb-C bonding is observed experimentally at six carbons. Clusters consisting of an odd number of atoms are also observed with linear geometries. The larger binary clusters (n > or = 7) display properties similar to those of pure carbon clusters. We provide evidence for niobium substitution of carbon atoms.

Anion Photoelectron Spectroscopy and Density Functional Investigation of Vanadium Carbide Clusters

The influence of source conditions on vanadium-carbon cluster formation in a methane-vanadium plasma is explored and analyzed by photoelectron spectroscopy, revealing that the metal-carbon ratio has substantial influence over the cluster products. Experiments that employ large methane content produce carbon-rich mono- and divanadium carbides. The carbon-rich clusters show a preference for the formation of cyclic neutral and linear ionic structures. When the methane concentration is decreased, VmCn clusters are formed with m = 1-4 and n = 2-8. The photoelectron spectra of clusters formed under these conditions are indicative of a three-dimensional network. We have measured a significantly lower vertical electron affinity for the VC2, V2C3, and V4C6 clusters compared with proximate species. Interestingly, the VC2 species is a proposed building block of the M8C12 Met-Car cluster, and the 2,3 and 4,6 clusters correspond to the 1/4 and 1/2 Met-Car cages, respectively. This correlation is taken as evidence of their importance in the formation of the larger Met-Car species. These results are supported by density functional theory (DFT) calculations carried out at the PBE/GGA level.

The Wnt antagonist sFRP1 is downregulated in premalignant large bowel adenomas

Our previous studies have implicated the Wnt antagonist, sFRP1, as a tumour suppressor gene in advanced colorectal cancer. In this study, we set out to investigate the relationship between sFRP1 expression and large bowel adenomas, a precursor of colorectal cancer. The induction of β-catenin/TCF mediated transcription is both a frequent early event in colorectal neoplasia, and a key downstream effect of wnt growth factor signalling. Lithium treatment of a small bowel mucosal cell line (FHs 74 int) induced sFRP1 within 8 h, indicating that this gene is positively regulated by β-catenin, contrasting with the suppression of sFRP1 expression, we saw previously in advanced colorectal cancers. We therefore investigated a series of 12 adenomas and matched large bowel mucosa samples. Real-time RT–PCR analysis showed a reduction in sFRP1 expression in all 12 dysplastic lesions (median 485-fold, IQR 120- to 1500-fold), indicating factors other than β-catenin influence sFRP1 levels. In a second series of 11 adenomas, we identified methylation of the sFRP1 promotor region in all 11 samples, and this was increased compared with the surrounding normal mucosa in seven cases. Immunohistochemical analysis using a polyclonal antibody supported these findings, with sFRP1 expression reduced in many of the adenoma samples examined. sFRP1 staining in normal mucosa adjacent to the dysplastic tissue was also reduced compared with the normal controls, suggesting that sFRP1 expression may be suppressed in a field of mucosa rather than in individual cells. This study identifies sFRP1 inactivation at the premalignant stage of colorectal cancer development, indicating that these pathways may be useful targets for chemoprevention strategies in this common solid tumour.

Structural MRI of carotid artery atherosclerotic lesion burden and characterization of hemispheric cerebral blood flow before and after carotid endarterectomy

Collateral circulation plays a major role in maintaining cerebral blood flow (CBF) in patients with internal carotid artery (ICA) stenosis. CBF can remain normal despite severe ICA stenosis, making the benefit of carotid endarterectomy (CEA) or stenting difficult to assess. Before and after surgery, we assessed CBF supplied through the ipsilateral (stenotic) or contralateral ICA individually with a novel hemisphere-selective arterial spin-labeling (ASL) perfusion MR technique. We further explored the relationship between CBF and ICA obstruction ratio (OR) acquired with a multislice black-blood imaging sequence. For patients with unilateral ICA stenosis (n = 19), conventional bilateral labeling did not reveal interhemispheric differences. With unilateral labeling, CBF in the middle cerebral artery (MCA) territory on the surgical side from the ipsilateral supply (53.7 +/- 3.3 ml/100 g/min) was lower than CBF in the contralateral MCA territory from the contralateral supply (58.5 +/- 2.7 ml/100 g/min), although not statistically significant (p = 0.09). The ipsilateral MCA territory received significant (p = 0.02) contralateral supply (7.0 +/- 2.7 ml/100 g/min), while ipsilateral supply to the contralateral side was not reciprocated. After surgery (n = 11), ipsilateral supply to the MCA territory increased from 57.3 +/- 5.7 to 67.3 +/- 5.4 ml/100 g/min (p = 0.03), and contralateral supply to the ipsilateral MCA territory decreased. The best predictor of increased CBF on the side of surgery was normalized presurgical ipsilateral supply (r(2) = 0.62, p = 0.004). OR was less predictive of change, although the change in normalized contralateral supply was negatively correlated with OR(excess) (=OR(ipsilateral) - OR(contralateral)) (r(2) = 0.58, p = 0.006). The results demonstrate the effect of carotid artery stenosis on blood supply to the cerebral hemispheres, as well as the relative role of collateral pathways before surgery and redistribution of blood flow through these pathways after surgery. Unilateral ASL may better predict hemodynamic surgical outcome (measured by improved perfusion) than ICA OR.

Refractive index distribution and optical properties of the isolated human lens measured using magnetic resonance imaging (MRI)

Using a non-invasive MRI technique for measuring the refractive index distribution through the crystalline lens, refractive index maps were obtained through 20 intact isolated human lenses (7-82years). Focal length measurements, obtained by simulated light ray propagation through each index map were found to be in agreement with direct measurements performed on a scanning laser apparatus. With increasing age, the refractive index profiles became flatter in the central region, accompanied by steepening of the profile in the periphery. This appears to be an important mechanism underlying the observed changes in power and longitudinal aberration of the human lens.

Parity-violating electron deuteron scattering and the proton's neutral weak axial vector form factor

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2=0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51+/-0.57 (stat)+/-0.58 (syst) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions.

Measuring optical properties of an eye lens using magnetic resonance imaging

We compare the focal lengths of porcine lenses measured optically and by using a novel MRI technique. The geometric properties of the lenses were also measured and compared. The MRI technique exploits the dependence of both the lens refractive index and relaxation rates on the local protein concentration. By measuring the refractive index and corresponding values of R2 (=1/T2) for samples of lens homogenates with different protein concentrations, the dependence of refractive index on R2 was determined empirically. R2 maps, constructed from monoexponential fits to multiecho images of a slice through the lens containing the optical axis, were converted to refractive index maps using this relationship. A simulated ray trace through the refractive index map provided an estimate of lens focal length that was compared to a direct optical measurement of focal length using a laser ray-tracing method. It was found that the mean focal lengths estimated from the two techniques agreed within experimental uncertainty. The refractive index profile along the optical axis was found to be well described by a simple function of the form n=n0 + n1 x ra where r is the (normalized) lens radius.

Prevalence of antibiotic-resistant propionibacteria on the skin of acne patients: 10-year surveillance data and snapshot distribution study

BACKGROUND

Cutaneous propionibacteria are implicated in acne pathogenesis, although their exact role in the genesis of inflammation is still poorly understood. Agents, including antibiotics, that reduce the numbers of propionibacteria on skin are therapeutic. Resistance in the target organism is a well-recognized consequence of antibiotic therapy for acne but formal prevalence and distribution data are lacking.

OBJECTIVES

To monitor the prevalence of skin colonization by antibiotic-resistant propionibacteria in acne patients attending the dermatology out-patient clinic at Leeds General Infirmary over a 10-year period beginning in 1991, and to examine the distribution of resistant strains on acne-prone skin and in the nares.

METHODS

Propionibacterial samples were obtained from the skin surface of the worst affected site (usually the face) of 4274 acne patients using a moistened swab. The swab was used to inoculate agar plates with and without selective antibiotics. After anaerobic incubation at 37 degrees C for 7 days, the amount of growth in the presence of each antibiotic was scored on a scale from 0 to 5+. A small number of patients (72) were selected for more detailed quantitative sampling at six different sites to examine the distribution of resistant propionibacteria on acne-prone skin and in the anterior nares.

RESULTS

The proportion of patients carrying strains resistant to one or more commonly used antiacne antibiotics rose steadily from 34.5% in 1991 to a peak of 64% in 1997. The prevalence dropped to 50.5% during 1999 and then rose again to 55.5% in 2000. Resistance to erythromycin was the most common and the majority of erythromycin-resistant strains were cross-resistant to clindamycin. Resistance to tetracyclines was less common in all years and with little increase over time. The more detailed quantitative study in 72 patients showed that population densities of resistant propionibacteria varied considerably between sites and between individuals. Almost invariably, patients were colonized with resistant strains at multiple sites, including the nares.

CONCLUSIONS

Skin colonization with antibiotic-resistant propionibacteria is much more common now than a decade ago. Resistant propionibacteria are widely distributed on acne-prone skin and in the nares. This suggests that they will be very difficult to eradicate using existing therapeutic regimens, especially from the nasal reservoir.

A randomized trial of sodium fluoride (60 mg) +/- estrogen in postmenopausal osteoporotic vertebral fractures: increased vertebral fractures and peripheral bone loss with sodium fluoride; concurrent estrogen prevents peripheral loss, but not vertebral fractures

Postmenopausal Caucasian women aged less than 80 years (n = 99) with one or more atraumatic vertebral fracture and no hip fractures, were treated by cyclical administration of enteric coated sodium fluoride (NaF) or no NaF for 27 months, with precautions to prevent excessive stimulation of bone turnover. In the first study 65 women, unexposed to estrogen (-E study), age 70.8 +/- 0.8 years (mean +/- SEM) were all treated with calcium (Ca) 1.0-1.2 g daily and ergocalciferol (D) 0.25 mg per 25 kg once weekly and were randomly assigned to cyclical NaF (6 months on, 3 months off, initial dose 60 mg/day; group F CaD, n = 34) or no NaF (group CaD, n = 31). In the second study 34 patients, age 65.5 +/- 1.2 years, on hormone replacement therapy (E) at baseline, had this standardized, and were all treated with Ca and D and similarly randomized (FE CaD, n = 17; E CaD, n = 17) (+E study). The patients were stratified according to E status and subsequently assigned randomly to +/- NaF. Seventy-five patients completed the trial. Both groups treated with NaF showed an increase in lumbar spinal density (by DXA) above baseline by 27 months: FE CaD + 16.2% and F CaD +9.3% (both p = 0.0001). In neither group CaD nor E CaD did lumbar spinal density increase. Peripheral bone loss occurred at most sites in the F CaD group at 27 months: tibia/fibula shaft -7.3% (p = 0.005); femoral shaft -7.1% (p = 0.004); distal forearm -4.0% (p=0.004); total hip -4.1% (p = 0.003); and femoral neck -3.5% (p = 0.006). No significant loss occurred in group FE CaD. Differences between the two NaF groups were greatest at the total hip at 27 months but were not significant [p < 0.05; in view of the multiple bone mineral density (BMD) sites, an alpha of 0.01 was employed to denote significance in BMD changes throughout this paper]. Using Cox's proportional hazards model, in the -E study there were significantly more patients with first fresh vertebral fractures in those treated with NaF than in those not so treated (RR = 24.2, p = 0.008, 95% CI 2.3-255). Patients developing first fresh fractures in the first 9 months were markedly different between groups: -23% of F CaD, 0 of CaD, 29% of FE CaD and 0 of E CaD. The incidence of incomplete (stress) fractures was similar in the two NaF-treated groups. Complete nonvertebral fractures did not occur in the two +E groups; there were no differences between groups F CaD and CaD. Baseline BMD (spine and femoral neck) was related to incident vertebral fractures in the control groups (no NaF), but not in the two NaF groups. Our results and a literature review indicate that fluoride salts, if used, should be at low dosage, with pretreatment and co-treatment with a bone resorption inhibitor.

Precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e, e')

We present the first precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e,e') at Q2 values of 0.1 and 0.2 (GeV/c)2. The agreement between the data and nonrelativistic Faddeev calculations which include both final-state interactions and meson-exchange current effects is very good at Q2 = 0.1 (GeV/c)2, while a small discrepancy at Q2 = 0.2 (GeV/c)2 is observed.

Bacteriophage T4 gene 41 helicase and gene 59 helicase-loading protein: a versatile couple with roles in replication and recombination

Bacteriophage T4 uses two modes of replication initiation: origin-dependent replication early in infection and recombination-dependent replication at later times. The same relatively simple complex of T4 replication proteins is responsible for both modes of DNA synthesis. Thus the mechanism for loading the T4 41 helicase must be versatile enough to allow it to be loaded on R loops created by transcription at several origins, on D loops created by recombination, and on stalled replication forks. T4 59 helicase-loading protein is a small, basic, almost completely alpha-helical protein whose N-terminal domain has structural similarity to high mobility group family proteins. In this paper we review recent evidence that 59 protein recognizes specific structures rather than specific sequences. It binds and loads the helicase on replication forks and on three- and four-stranded (Holliday junction) recombination structures, without sequence specificity. We summarize our experiments showing that purified T4 enzymes catalyze complete unidirectional replication of a plasmid containing the T4 ori(uvsY) origin, with a preformed R loop at the position of the R loop identified at this origin in vivo. This replication depends on the 41 helicase and is strongly stimulated by 59 protein. Moreover, the helicase-loading protein helps to coordinate leading and lagging strand synthesis by blocking replication on the ori(uvsY) R loop plasmid until the helicase is loaded. The T4 enzymes also can replicate plasmids with R loops that do not have a T4 origin sequence, but only if the R loops are within an easily unwound DNA sequence.

Muscle fiber and satellite cell apoptosis in the aging human thyroarytenoid muscle: a stereological study with confocal laser scanning microscopy

OBJECTIVE

This study determines the role of changes in numerical densities of apoptotic myonuclei and satellite cells in age-related remodeling of the thyroarytenoid muscle (TA).

DESIGN

Changes in numerical densities of apoptotic myonuclei and satellite cells were estimated for the entire TA by using stereological techniques.

RESULTS

There was an increase in N(V apoptotic myonucleus, fiber type) (P < 0.05) and in the percentage of apoptotic myonuclei (P < 0.05) in type 1 but not in type 2 muscle fibers. There was also an increase in N(V apoptotic satellite cell, fiber type) (P < 0.05) and in the percentage of apoptotic satellite cells (P < 0.05) in type 1 fibers but not in type 2 fibers.

CONCLUSION

Apoptosis may contribute to age-related fiber loss and atrophy in the TA.

SIGNIFICANCE

Therapeutic techniques based on decreasing the frequency of apoptosis may block age-related fiber loss and atrophy in the TA.

Evidence for a three-nucleon-force effect in proton-deuteron elastic scattering

Developments in spin-polarized internal targets for storage rings have permitted measurements of 197 MeV polarized protons scattering from vector polarized deuterons. This work presents measurements of the polarization observables A(y), iT11, and C(y,y) in proton-deuteron elastic scattering. When compared to calculations with and without three-nucleon forces, the measurements provide further evidence that three-nucleon forces make a contribution to the observables. This work indicates that three-body forces derived from static nuclear properties appear to be crucial to the description of dynamical properties.

Strange magnetism and the anapole structure of the proton

The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

Transverse asymmetry AT' from the quasielastic 3He(e,e') process and the neutron magnetic form factor

We have measured the transverse asymmetry A(T') in 3He(e,e(')) quasielastic scattering in Hall A at Jefferson Laboratory with high precision for Q2 values from 0.1 to 0.6 (GeV/c)(2). The neutron magnetic form factor G(n)(M) was extracted based on Faddeev calculations for Q2 = 0.1 and 0.2 (GeV/c)(2) with an experimental uncertainty of less than 2%.

Numerical densities of myonuclei and satellite cells in muscle fiber types in the aging human thyroarytenoid muscle: an immunohistochemical and stereological study using confocal laser scanning microscopy

OBJECTIVE

This study determines the role of changes in numerical densities of myonuclei and satellite cells in age-related remodeling of the thyroarytenoid muscle (TA).

DESIGN

Changes in numerical densities (N(V)) and ratios (N(N)) of myonuclei and satellite cells were estimated for the entire TA by use of stereological techniques.

RESULTS

There was no age-related change or difference between fiber types for N(V myonucleus, fiber), but N(V myonucleus, fiber) increased with decreasing fiber diameter. There was a trend toward a decrease in N(V satellite cell, fiber) and a decrease in N(N satellite cell, myonucleus). N(V satellite cell, fiber) was higher for type 1 than for type 2 fibers, and type 1 satellite cells increased disproportionately with increasing total satellite cell numerical density.

CONCLUSION

Decreased satellite cell proliferation may contribute to age-related fiber loss and atrophy in the TA.

SIGNIFICANCE

Therapeutic techniques based on activation of satellite cells may block age-related fiber loss and atrophy in the TA.

Interaction of the bacteriophage T4 gene 59 helicase loading protein and gene 41 helicase with each other and with fork, flap, and cruciform DNA

Bacteriophage T4 gene 59 helicase loading protein accelerates the loading of T4 gene 41 DNA helicase and is required for recombination-dependent DNA replication late in T4 phage infection. The crystal structure of 59 protein revealed a two-domain alpha-helical protein, whose N-terminal domain has strong structural similarity to the DNA binding domain of high mobility group family proteins (Mueser, T. C., Jones, C. E., Nossal, N. G., and Hyde, C. C. (2000) J. Mol. Biol. 296, 597-612). We have previously shown that 59 protein binds preferentially to fork DNA. Here we show that 59 protein binds to completely duplex forks but cannot load the helicase unless there is a single-stranded gap of more than 5 nucleotides on the fork arm corresponding to the lagging strand template. Consistent with the roles of these proteins in recombination, we find that 59 protein binds to and stimulates 41 helicase activity on Holliday junction DNA, and on a substrate that resembles a strand invasion structure. 59 protein forms a stable complex with wild type 41 helicase and fork DNA in the presence of adenosine 5'-O-(thiotriphosphate). The unwinding activity of 41 helicase missing 20 C-terminal amino acids is not stimulated by 59 protein, and it does not form a complex with 59 protein on fork DNA.

Relative patterns and rates of evolution in heron nuclear and mitochondrial DNA

Mitochondrial cytochrome b sequence data from 15 species of herons (Aves: Ardeidae), representing 13 genera, were compared with DNA hybridization data of single-copy nuclear DNA (scnDNA) from the same species in a taxonomic congruence assessment of heron phylogeny. The two data sets produced a partially resolved, completely congruent estimate of phylogeny with the following basic structure: (Tigrisoma, Cochlearius, (((Zebrilus, (Ixobrychus, Botaurus)), (((Ardea, Casmerodius), Bubulcus), ((Egretta thula, Egretta caerulea, Egretta tricolor), Syrigma), Butorides, Nycticorax, Nyctanassa)))). Because congruence indicated similar phylogenetic information in the two data sets, we used the relatively unsaturated DNA hybridization distances as surrogates of time to examine graphically the patterns and rates of change in cytochrome b distances. Cytochrome b distances were computed either from whole sequences or from partitioned sequences consisting of transitions, transversions, specific codon site positions, or specific protein-coding regions. These graphical comparisons indicated that unpartitioned cytochrome b has evolved at 5-10 times the rate of scnDNA. Third-position transversions appeared to offer the most useful sequence partition for phylogenetic analysis because of their relatively fast rate of substitution (two times that of scnDNA) and negligible saturation. We also examined lineage-based rates of evolution by comparing branch length patterns between the nuclear and cytochrome b trees. The degree of correlation in corresponding branch lengths between cytochrome b and DNA hybridization trees depended on DNA sequence partitioning. When cytochrome b sequences were not partitioned, branch lengths in the cytochrome b and DNA hybridization trees were not correlated. However, when cytochrome b sequences were reduced to third-position transversions (i.e., unsaturated, relatively fast changing data), branch lengths were correlated. This finding suggests that lineage-based rates of DNA evolution in nuclear and mitochondrial genomes are influenced by common causes.

Bacteriophage T4 gene 59 helicase assembly protein binds replication fork DNA. The 1.45 A resolution crystal structure reveals a novel alpha-helical two-domain fold

The bacteriophage T4 gene 59 helicase assembly protein is required for recombination-dependent DNA replication, which is the predominant mode of DNA replication in the late stage of T4 infection. T4 gene 59 helicase assembly protein accelerates the loading of the T4 gene 41 helicase during DNA synthesis by the T4 replication system in vitro. T4 gene 59 helicase assembly protein binds to both T4 gene 41 helicase and T4 gene 32 single-stranded DNA binding protein, and to single and double-stranded DNA. We show here that T4 gene 59 helicase assembly protein binds most tightly to fork DNA substrates, with either single or almost entirely double-stranded arms. Our studies suggest that the helicase assembly protein is responsible for loading T4 gene 41 helicase specifically at replication forks, and that its binding sites for each arm must hold more than six, but not more than 12 nucleotides. The 1.45 A resolution crystal structure of the full-length 217-residue monomeric T4 gene 59 helicase assembly protein reveals a novel alpha-helical bundle fold with two domains of similar size. Surface residues are predominantly basic (pI 9.37) with clusters of acidic residues but exposed hydrophobic residues suggest sites for potential contact with DNA and with other protein molecules. The N-terminal domain has structural similarity to the double-stranded DNA binding domain of rat HMG1A. We propose a speculative model of how the T4 gene 59 helicase assembly protein might bind to fork DNA based on the similarity to HMG1, the location of the basic and hydrophobic regions, and the site size of the fork arms needed for tight fork DNA binding. The fork-binding model suggests putative binding sites for the T4 gene 32 single-stranded DNA binding protein and for the hexameric T4 gene 41 helicase assembly.

Parity violation in elastic electron-proton scattering and the Proton's strange magnetic form factor

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92+/-0.61+/-0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.

Purification and characterization of human Syk produced using a baculovirus expression system

The cytoplasmic tyrosine kinase p72syk (Syk) plays an essential role in signaling via a variety of immune and nonimmune cell receptors. Syk is activated in response to the engagement of the appropriate cell surface receptors and can phosphorylate downstream targets and recruit additional SH2-domain-containing proteins. In order to study the characteristics of Syk in vitro, we have overexpressed untagged, full-length human Syk in a recombinant baculovirus expression system. The enzyme was purified to 95% purity using a novel two-step affinity chromatography process using reactive yellow and phosphotyrosine columns. Yields of 3-10 mg purified Syk were obtained from 1 liter of infected insect cells. Western blotting, internal protein sequencing, and the specific tyrosine phosphorylation of a Syk peptide substrate indicated authenticity of the purified protein. The enzymatic properties of Syk were in good agreement with published data for the human enzyme, as the apparent K(m) of Syk for ATP was 10 microM and the peptide substrate was 3 microM. The recombinant protein also showed similar biochemical characteristics to the native protein isolated from B-cells such as autophosphorylation. Proteolytic cleavage of purified recombinant Syk was used to generate the kinase domain by micro-calpain. We therefore describe an efficient expression system and purification methodology to produce biologically active human Syk.

Intracellular copper routing: the role of copper chaperones

Copper is required by all living systems. Cells have a variety of mechanisms to deal with this essential, yet toxic trace element. A recently discovered facet of homeostatic mechanisms is the protein-mediated, intracellular delivery of copper to target proteins. This routing is accomplished by a novel class of proteins, the 'copper chaperones'. They are a family of conserved proteins present in prokaryotes and eukaryotes, which suggests that copper chaperones are used throughout nature for intracellular copper routing.

The kinetics of mycophenolic acid and its glucuronide metabolite in adult kidney transplant recipients

BACKGROUND

Mycophenolic acid kinetics have been reported to vary after renal transplantation, and mycophenolic acid area under the concentration-time curve (AUC) is the best predictor of suppression of graft rejection.

METHODS

To determine whether mycophenolic acid kinetics vary after renal transplantation and to examine the potential role of enterohepatic recirculation, we investigated the kinetics of mycophenolic acid and mycophenolic acid glucuronide on days 2, 5, and 28 after transplantation in 10 kidney transplant recipients (male/female ratio, 1.5; mean age, 41.7 +/- 5.0 years) given 1 g mycophenolate mofetil twice a day. To facilitate therapeutic drug monitoring, we examined a limited sampling strategy for estimating 12-hour mycophenolic acid [AUC(0-12)].

RESULTS

The mean +/- SE AUC(0-12) for mycophenolic acid on day 28 was 38.5 +/- 1.6 mg x h/L, with a secondary peak 4 to 8 hours after dosing that was attributable to enterohepatic recirculation. Marked variability was shown in the kinetic profile of mycophenolic acid among patients across the three sampling days. Mycophenolic acid AUC(0-12) was positively predicted by both serum creatinine (P = .01) and serum albumin (P = .03) but not by time after transplantation, body weight, or trough concentration. Limited sampling (at 0, 1, 3, and 6 hours) accounted for 84.1% of the variability in the mycophenolic acid AUC(0-12) data and predicted the AUC(0-12) closely (r2 = 0.954) when evaluated in 10 different kidney transplant recipients.

CONCLUSIONS

Mycophenolic acid AUC(0-12) is predicted by serum albumin and creatinine after kidney transplantation, and the AUC(0-12) may be determined during the early posttransplant period while the patient remains hospitalized with use of a limited sampling strategy to facilitate therapeutic drug monitoring.

Copper chaperones: function, structure and copper-binding properties

Copper is an absolute requirement for living systems and the intracellular trafficking of this metal to copper-dependent proteins is fundamental to normal cellular metabolism. The copper chaperones perform the dual functions of trafficking and the prevention of cytoplasmic exposure to copper ions in transit. Only a small number of copper chaperones have been identified at this time but their conservation across plant, bacterial and animal species suggests that the majority of living systems utilise these proteins for copper routing. The available data suggest that each copper-dependent protein in the cell is served by a specific copper chaperone. Although copper chaperones cannot be substituted for one another in a given cell type, copper chaperones that deliver to the same protein in different cell types appear to be functionally equivalent. The majority of the copper chaperones identified thus far have an "open-faced beta-sandwich" global fold with a conserved MXCXXC metal-binding motif. Specificity for a given copper-dependent protein appears to be mediated by the residues surrounding the copper-binding motif. Copper binds to such proteins as Cu(I) in a trigonal complex with three sulfur ligands. Only the copper chaperone specific for cytochrome-c-oxidase, Cox17, deviates from this design.

Floral morphological changes and reproductive success in deer weed (Lotus scoparius

Pollination-related and time-dependent floral morphological changes occur in a diverse set of angiosperm taxa and appear to be particularly common in species occupying resource-limited environments. In deer weed (Lotus scoparius), such floral modifications include a color change from yellow to orange and a folding of the banner petal down over the keel. These changes are rapidly induced by pollination, but will also occur much more slowly without pollination. Orange flowers typically lack nectar and pollen. We examined the reproductive success of these plants to test the hypothesis that retention of orange flowers increases pollinator visitation rate and fruit set while reducing costs to the pollinators. All of the common species of bee pollinators that visited deer weed easily distinguished between yellow and orange flowers at close range and preferentially probed yellow flowers. Retention of orange flowers by these plants resulted in a higher frequency of pollinator visits and a higher fruit set per flower than plants that lacked orange flowers. The number of flowers visited by each pollinator was lower on plants with a mixture of yellow and orange flowers, suggesting that the presence of orange flowers may reduce selfing. The possible selective pressures involved in the evolution of these mechanisms and their relation to stressful environments are also discussed.

Evaluation of an immunoassay (EMIT) for mycophenolic acid in plasma from renal transplant recipients compared with a high-performance liquid chromatography assay

Mycophenolic acid is an immunosuppressant administered as a bioavailable ester, mycophenolate mofetil. The pharmacokinetics of mycophenolic acid have been reported to be variable. Accurate measurement of concentrations of this drug could be important to adjust doses. The aim of this study was to compare the enzyme-multiplied immunoassay technique (EMIT [Dade Behring; San Jose, CA, U.S.A.]) for mycophenolic acid with a high-performance liquid chromatographic (HPLC) assay using samples collected from renal transplant recipients. The HPLC assay used solid phase extraction and a C18 stationary phase with ultraviolet (UV) detection (254 nm). The immunoassay required no manual sample preparation. Plasma samples (n=102) from seven patients, collected at various times after a dose, were analyzed using both methods. Both assays fulfilled quality-control criteria. Higher concentrations were consistently measured in patient samples when using EMIT. The mean (+/-standard deviation [SD]) bias (EMIT-HPLC) was 1.88+/-0.86 mg/L. The differences in concentrations were higher in the middle of a dosage interval, suggesting that a metabolite might have been responsible for overestimation. Measurement of glucuronide concentrations by HPLC demonstrated only a weak correlation between assay differences and glucuronide concentrations. If the crossreacting substance is active, EMIT could provide a superior measure of immunosuppression; if inactive, further work is needed to improve antibody specificity. In conclusion, it was found that EMIT overestimates the concentration of mycophenolic acid in plasma samples from renal transplant recipients compared with HPLC analysis.

Plasma indomethacin assay using high-performance liquid chromatography-electrospray-tandem mass spectrometry: application to therapeutic drug monitoring and pharmacokinetic studies

The authors report the use of high-performance liquid chromatography-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS) for the quantification of indomethacin (IND) in plasma with microscale sample preparation. Plasma samples (100 microL) and mefanamic acid (internal standard [IS]), buffered to pH 3.5, were prepared using solid phase extraction and chromatographed using a C8 column. The mobile phase composition was 80% methanol to 20% ammonium acetate buffer (40 mM, pH 5.1). A flow rate of 300 microL per minute was used with a 1-to-12 postcolumn split into the mass spectrometer. Selected reaction monitoring with mass transitions m/z 357.9-->139.0 and m/z 242-->209.0 were used for IND and IS, respectively. The chromatographic analysis time was 4 minutes. The assay was linear from 5 microg/L to 2000 microg/L with interday imprecision (n=5) over the analytic range (5%). At four concentrations (10 microg/L, 25 microg/L, 250 microg/L, 1500 microg/L), assay imprecision was 9% (total coefficient of variation [CV]) and accuracy ranged between 96.5% and 102.8% (n=16). The absolute recovery of IND and IS was 74% (n=8) and 95% (n=24), respectively. This method was developed and validated in less than 10 working days, had a lower limit of quantification than reported HPLC-ultraviolet (UV) methods, and uses small sample volumes. These factors illustrate the power of HPLC-ESI-MS/MS for drug analysis. Furthermore, the ability of this method to measure IND over a wide concentration range makes it suitable for therapeutic drug monitoring and pharmacokinetic studies.

The Kidney's role in glucose balance following partial hepatectomy

It has long been believed that the liver is the major contributor to glucose balance during fasting and stressful situations. Recently, investigators have implicated the kidney as having a significant contribution to systemic glucose appearance. We studied the relative contributions of the kidney and liver to glucose homeostasis in fasted nonoperated, sham-operated, and 70% hepatectomized rats. Systemic glucose appearance, renal glucose release and uptake, and hepatic glucose release were determined by glucose balance and isotopic dilution techniques. Systemic glucose appearance remained unchanged following hepatectomy. There was a significant output of glucose by the kidney in all groups, accounting for >50% of total glucose appearance. Despite the kidney's appreciable contribution to circulating glucose in the postabsorptive state, renal glucose release was not increased in the hepatectomized rats compared to controls. Total glucose appearance was maintained following hepatectomy by an increase in hepatic glucogenesis. There was a significant increase in the rate of hepatic glucose release from resected rats when normalized to gram of remaining liver (P < 0.001). Despite the substantial amount of renal glucose output in the postabsorptive state, preservation of glucose balance following 70% hepatectomy is accomplished by adaptation in hepatic glucose output.

Inhibition of human peripheral blood mononuclear cell proliferation by Streptococcus pyogenes cell extract is associated with arginine deiminase activity

Streptococcus pyogenes (group A Streptococcus) cell extracts (CE) have a remarkably powerful and dose-dependent inhibitory effect on antigen, superantigen, or mitogen-stimulated human peripheral blood mononuclear cell (PBMC) proliferation in vitro. Purification of the inhibitory component present in S. pyogenes type M5 (Manfredo strain) CE by anion-exchange chromatography followed by gel filtration chromatography showed that the inhibitor had an approximate native molecular mass of 100 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified inhibitory fractions followed by silver staining gave a single band with an approximate molecular mass of 47 kDa, indicating that the inhibitor is composed of two identical subunits. NH2-terminal sequencing of the protein revealed that it was identical to the previously characterized streptococcal acid glycoprotein (SAGP); this protein possesses between 31.5 and 39.0% amino acid identity with arginine deiminase (AD) from Mycoplasma hominis, Mycoplasma arginini, Pseudomonas putida, and Pseudomonas aeruginosa. AD enzyme activity was present in unfractionated CE prepared from a range of streptococcal strains, and partially purified inhibitory fractions of Manfredo CE also had high levels of activity. The inhibitory effect of Manfredo CE was overcome by the addition of L-arginine to proliferation assays in which human PBMC were stimulated with phytohemagglutinin. We conclude that SAGP, or its homolog, possesses AD activity and that the potent inhibition of proliferation of human T cells by streptococcal CE is due to activity of this enzyme.

Characterization, crystallization and preliminary X-ray investigation of glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon Sulfolobus solfataricus

Recombinant Sulfolobus solfataricus glyceraldehyde-3-phosphate dehydrogenase has been purified and found to be a tetramer of 148 kDa. The enzyme shows dual cofactor specificity and uses NADP+ in preference to NAD+. The sequence has been compared with other GAPDH proteins including those from other archaeal sources. The purified protein has been crystallized from ammonium sulfate to produce crystals that diffract to 2.4 A with a space group of P43212 or P41212. A native data set has been collected to 2.4 A using synchrotron radiation and cryocooling.

Production of human tissue factor using the Pichia pastoris expression system

Tissue factor plays an important role in the initiation of the blood coagulation cascade resulting in the formation of a fibrin clot. The extracellular domain of human tissue factor has been expressed in the protease-deficient strain of the methylotrophic yeast Pichia pastoris, SMD1168. Tissue factor was expressed with a human influenza hemagglutinin tag fused at the C-terminus under control of the regulatory sequences from the Pichia AOX1 gene. Expressed protein was secreted in a soluble form at levels of up to 10 mg L-1 and correct processing of the PHO1 signal sequence was confirmed by N-terminal amino acid sequence analysis. Tissue factor was produced in Pichia as three discrete forms which appeared as three bands in the range 37-45 kDa by SDS-PAGE. These were all recognized by an anti-tissue factor monoclonal antibody. Deglycosylation studies using Endo H showed that the three forms were the result of differences in glycosylation of the protein. The low levels of secreted proteins produced by P. pastoris make this an efficient host for producing biologically active recombinant tissue factor requiring little purification.

Estrogen replacement reverses endothelial dysfunction in postmenopausal women

PURPOSE

To measure the effect of long-term clinical hormone replacement therapy on brachial artery vasomotor responses, and to compare these responses in premenopausal and postmenopausal women.

PATIENTS AND METHODS

We studied 23 postmenopausal women, including 18 who were evaluated prior to starting clinically indicated oral hormone replacement therapy. Twelve postmenopausal women received estrogen alone, the other 6 were treated with estrogen/medroxyprogesterone combinations. Eleven premenopausal volunteers served as a comparison group. Change in brachial artery diameter in response to postischemic hyperemic flow and sublingual nitroglycerin was measured by ultrasound.

RESULTS

The 18 postmenopausal subjects receiving hormone replacement showed a progressive improvement in their postischemic vasodilation. Mean (+/-SD) postischemic vasodilation was 0.4%+/-7.1% prior to estrogen replacement. There were significant increases in postischemic vasodilation of 4.8%+/-6.6% after 1 month and 8.3%+/-3.4% after 6 months of estrogen replacement. The response to nitroglycerin was similar at all time points studied. Women with the most abnormal responses to hyperemic flow at baseline demonstrated the greatest improvement after 6 months of hormone replacement therapy. Premenopausal and postmenopausal subjects differed in their response to hyperemic flow, with premenopausal women showing 5.8% vasodilatation compared with a 0.6% vasodilation in postmenopausal women (P=0.046).

CONCLUSIONS

Endothelial function is abnormal in many postmenopausal women compared with premenopausal women, and in some postmenopausal women it can be enhanced by estrogen replacement therapy. This effect may increase with prolonged use.

High-performance liquid chromatography determination of mycophenolic acid and its glucuronide metabolite in human plasma

Two HPLC-UV assays are reported here: one is a rapid assay for mycophenolic acid (MPA) and the other is a simultaneous assay for MPA and its metabolite mycophenolic acid glucuronide (MPAG). For both methods, plasma samples (500 microl) with added internal standard were acidified and extracted using C18 solid-phase extraction cartridges. Chromatographic separation was achieved on a C18 Novapak column using a mobile phase consisting of methanol-0.05% orthophosphoric acid (40:60, v/v) for the rapid MPA assay and 30:70 for the simultaneous MPA and MPAG assay. The assays were linear over the ranges 0.1 to 50.0 mg/l for MPA and 2.8 to 225.8 mg/l for MPAG. Mean absolute recovery for all analytes was >99%. These methods are suitable for therapeutic drug monitoring and pharmacokinetic studies.

Microscale high-performance liquid chromatography-electrospray tandem mass spectrometry assay for cyclosporin A in blood

To facilitate quantitative analysis of cyclosporin A in low volume blood samples we developed a sensitive and specific microscale reversed-phase HPLC-electrospray tandem mass spectrometry assay. Blood samples (100 microl) were prepared by acetonitrile precipitation and C18 solid-phase extraction. Detection was by multiple-reactant monitoring. The method was linear over the range 5-1000 microg/l (r> or =0.997) with accuracy between 95.4 and 102.0% over this range. Total imprecision was 11.1% at 10 microg/l and 2.8% at 800 microg/l. Absolute recovery of cyclosporin A and internal standard was 72.5 and 73.3%, respectively. When this method was evaluated against a conventional HPLC with UV detection, in patient samples, they were interchangeable (y=0.988x + 10.0, r=0.996). This HPLC-ESI-MS-MS method will be applicable to therapeutic monitoring in paediatric transplant patients and multiple point pharmacokinetic studies in animals and humans.

Routine pulmonary artery catheterization does not reduce morbidity and mortality of elective vascular surgery: results of a prospective, randomized trial

OBJECTIVE

The authors determined whether the preoperative placement of a pulmonary artery catheter (PAC) with optimization of hemodynamics results in outcome improvement after elective vascular surgery.

SUMMARY BACKGROUND DATA

The PAC commonly is used not only in patients who are critically ill, but also perioperatively in major elective surgery. Few prospective studies exist documenting its usefulness.

METHODS

One hundred four consecutive patients were randomized to have a PAC placed the morning of operation (group I) or to have a PAC placed only if clinically indicated (group II). Group I patients were resuscitated to preestablished endpoints before surgery and kept at these points both intraoperatively and postoperatively. Group II patients received standard care.

RESULTS

There was one death in each group. An intraoperative or postoperative complication developed in 13 patients in group I versus 7 patients in group II (p = not significant). Group I patients received more fluid than did group II patients (5137 +/- 315 mL vs. 3789 +/- 306 mL; p < 0.003). There was no significant difference in either overall or surgical intensive care unit length of stay. Only one patient in group II required a postoperative PAC.

CONCLUSIONS

Routine PAC use in elective vascular surgery increases the volume of fluid given to patients without demonstrable improvement in morbidity or mortality.

Physiological and biochemical studies on psychrotolerance in Listeria monocytogenes

Studies were undertaken to explain the ability of Listeria monocytogenes to grow at low temperatures in a chemostat. It was found that when grown in continuous culture at a dilution rate of 0.02 h-1 L. monocytogenes had a lower proportion of anteiso-17:0, and a higher proportion of anteiso-15:0, and smaller chain fatty acids when grown at 10 degrees C compared to 30 degrees C. A previously unreported glycolipid was only seen after growth at low temperature. Growth temperature had no effect on the rate of glucose uptake.

Clinical resistance to erythromycin and clindamycin in cutaneous propionibacteria isolated from acne patients is associated with mutations in 23S rRNA

The genetic basis of erythromycin resistance in cutaneous propionibacteria was determined by comparing the nucleotide sequences of the peptidyl transferase region in the 23S rRNAs from 9 susceptible and 26 resistant clinical isolates as well as 4 laboratory-selected erythromycin-resistant mutants of a susceptible strain. In 13 isolates and the 4 laboratory mutants, cross-resistance to macrolides, lincosamides, and B-type streptogramins was associated with an A-->G transition at a position cognate with Escherichia coli 23S rRNA base 2058. These strains were resistant to > or = 512 microg of erythromycin per ml. Two other mutations were identified, an A-->G transition at base 2059 in seven strains, associated with high-level resistance to all macrolides, and a G-->A transition at base 2057 in six strains, associated with low-level resistance to erythromycin. These mutations correspond to three of four phenotypic classes previously identified by using MIC determinations.

A comparison of the dual lumen and coaxial catheters for temporary hemodialysis access

Percutaneous central venous catheterization can provide reliable temporary hemodialysis access. The current study compared the hemodynamic performance of 28 coaxial catheters to 27 side by side catheters. A total of 675 dialysis sessions were evaluated to assess the flow characteristics of these two designs. The results demonstrated that the side by side catheter provided greater cumulative blood flow with more favorable venous and arterial pressures. Nevertheless, the coaxial catheter performed satisfactorily and met the minimum standards for these devices.