Analysing and presenting qualitative data

This paper provides a pragmatic approach to analysing qualitative data, using actual data from a qualitative dental public health study for demonstration purposes. The paper also critically explores how computers can be used to facilitate this process, the debate about the verification (validation) of qualitative analyses and how to write up and present qualitative research studies.

ABT-378, a highly potent inhibitor of the human immunodeficiency virus protease

The valine at position 82 (Val 82) in the active site of the human immunodeficiency virus (HIV) protease mutates in response to therapy with the protease inhibitor ritonavir. By using the X-ray crystal structure of the complex of HIV protease and ritonavir, the potent protease inhibitor ABT-378, which has a diminished interaction with Val 82, was designed. ABT-378 potently inhibited wild-type and mutant HIV protease (Ki = 1.3 to 3.6 pM), blocked the replication of laboratory and clinical strains of HIV type 1 (50% effective concentration [EC50], 0.006 to 0.017 microM), and maintained high potency against mutant HIV selected by ritonavir in vivo (EC50, 50-fold after 8 h. In healthy human volunteers, coadministration of a single 400-mg dose of ABT-378 with 50 mg of ritonavir enhanced the area under the concentration curve of ABT-378 in plasma by 77-fold over that observed after dosing with ABT-378 alone, and mean concentrations of ABT-378 exceeded the EC50 for >24 h. These results demonstrate the potential utility of ABT-378 as a therapeutic intervention against AIDS.

In vitro and in vivo antitumor properties of the cyclin dependent kinase inhibitor CYC202 (R-roscovitine)

CDK2 inhibitors have been proposed as effective anti-cancer therapeutics. We show here that CYC202 (R-roscovitine) is a potent inhibitor of recombinant CDK2/cyclin E kinase activity (IC(50) = 0.10 microM) with an average cytotoxic IC(50) of 15.2 microM in a panel of 19 human tumour cell lines, and we also demonstrate selectivity for rapidly proliferating cells over non-proliferating cells. A study of the cell cycle effects of CYC202 in Lovo colorectal carcinoma cells showed that the major effect was not the predicted arrest in one part of the cycle, but rather an induction of cell death from all compartments of the cell cycle. The maximum tolerated dose given intravenously to mice was in excess of 20 mg/kg. Doses up to 2,000 mg/kg were tolerated when administered orally in mice. Following repeated intraperitoneal administration (3 times daily for 5 days) of 100 mg/kg to nude mice bearing the Lovo human colorectal tumour, CYC202 induced a significant antitumour effect with a 45% reduction in tumour growth compared to controls. A second experiment using the human uterine xenograft MESSA-DX5 treated with orally administered CYC202 (500 mg/kg 3 times daily for 4 days) also exhibited a significant reduction in the rate of growth of the tumour (62%). These data, showing enzyme and cellular potency together with antitumour activity, confirm the potential of CDK2 inhibitors such as CYC202 as anticancer drugs.

Scrapie replication in lymphoid tissues depends on prion protein-expressing follicular dendritic cells

The immune system is central in the pathogenesis of scrapie and other transmissible spongiform encephalopathies (TSEs) or 'prion' diseases. After infecting by peripheral (intraperitoneal or oral) routes, most TSE agents replicate in spleen and lymph nodes before neuroinvasion. Characterization of the cells supporting replication in these tissues is essential to understanding early pathogenesis and may indicate potential targets for therapy, for example, in 'new variant' Creutzfeldt-Jakob disease. The host 'prion' protein (PrP) is required for TSE agent replication and accumulates in modified forms in infected tissues. Abnormal PrP is detected readily on follicular dendritic cells (FDCs) in lymphoid tissues of patients with 'new variant' Creutzfeldt-Jakob disease, sheep with natural scrapie and mice experimentally infected with scrapie. The normal protein is present on FDCs in uninfected mice and, at lower levels, on lymphocytes. Studies using severe combined immunodeficiency (SCID) mice, with and without bone marrow (BM) grafts, have indicated involvement of FDCs and/or lymphocytes in scrapie pathogenesis. To clarify the separate roles of FDCs and lymphocytes, we produced chimeric mice with a mismatch in PrP status between FDCs and other cells of the immune system, by grafting bone marrow from PrP-deficient knockout mice into PrP-expressing mice and vice versa. Using these chimeric models, we obtained strong evidence that FDCs themselves produce PrP and that replication of a mouse-passaged scrapie strain in spleen depends on PrP-expressing FDCs rather than on lymphocytes or other bone marrow-derived cells.

A middle stone age worked bone industry from Katanda, Upper Semliki Valley, Zaire

Three archaeological sites at Katanda on the Upper Semliki River in the Western Rift Valley of Zaire have provided evidence for a well-developed bone industry in a Middle Stone Age context. Artifacts include both barbed and unbarbed points as well as a daggerlike object. Dating by both direct and indirect means indicate an age of approximately 90,000 years or older. Together with abundant fish (primarily catfish) remains, the bone technology indicates that a complex subsistence specialization had developed in Africa by this time. The level of behavioral competence required is consistent with that of upper Paleolithic Homo sapiens sapiens. These data support an African origin of behaviorally as well as biologically modern humans.

Vegetarian diets and incidence of diabetes in the Adventist Health Study-2

AIM

To evaluate the relationship of diet to incident diabetes among non-Black and Black participants in the Adventist Health Study-2.

METHODS AND RESULTS

Participants were 15,200 men and 26,187 women (17.3% Blacks) across the U.S. and Canada who were free of diabetes and who provided demographic, anthropometric, lifestyle and dietary data. Participants were grouped as vegan, lacto ovo vegetarian, pesco vegetarian, semi-vegetarian or non-vegetarian (reference group). A follow-up questionnaire after two years elicited information on the development of diabetes. Cases of diabetes developed in 0.54% of vegans, 1.08% of lacto ovo vegetarians, 1.29% of pesco vegetarians, 0.92% of semi-vegetarians and 2.12% of non-vegetarians. Blacks had an increased risk compared to non-Blacks (odds ratio [OR] 1.364; 95% confidence interval [CI], 1.093-1.702). In multiple logistic regression analysis controlling for age, gender, education, income, television watching, physical activity, sleep, alcohol use, smoking and BMI, vegans (OR 0.381; 95% CI 0.236-0.617), lacto ovo vegetarians (OR 0.618; 95% CI 0.503-0.760) and semi-vegetarians (OR 0.486, 95% CI 0.312-0.755) had a lower risk of diabetes than non-vegetarians. In non-Blacks vegan, lacto ovo and semi-vegetarian diets were protective against diabetes (OR 0.429, 95% CI 0.249-0.740; OR 0.684, 95% CI 0.542-0.862; OR 0.501, 95% CI 0.303-0.827); among Blacks vegan and lacto ovo vegetarian diets were protective (OR 0.304, 95% CI 0.110-0.842; OR 0.472, 95% CI 0.270-0.825). These associations were strengthened when BMI was removed from the analyses.

CONCLUSION

Vegetarian diets (vegan, lacto ovo, semi-) were associated with a substantial and independent reduction in diabetes incidence. In Blacks the dimension of the protection associated with vegetarian diets was as great as the excess risk associated with Black ethnicity.

MRI as a biomarker of disease progression in a therapeutic trial of milameline for AD

OBJECTIVE

To assess the feasibility of using MRI measurements as a surrogate endpoint for disease progression in a therapeutic trial for AD.

METHODS

A total of 362 patients with probable AD from 38 different centers participated in the MRI portion of a 52-week randomized placebo-controlled trial of milameline, a muscarinic receptor agonist. The therapeutic trial itself was not completed due to projected lack of efficacy on interim analysis; however, the MRI arm of the study was continued. Of the 362 subjects who underwent a baseline MRI study, 192 subjects underwent a second MRI 1 year later. Hippocampal volume and temporal horn volume were measured from the MRI scans.

RESULTS

The annualized percent changes in hippocampal volume (-4.9%) and temporal horn volume (16.1%) in the study patients were consistent with data from prior single-site studies. Correlations between the rate of MRI volumetric change and change in behavioral/cognitive measures were greater for the temporal horn than for the hippocampus. Decline over time was more consistently seen with imaging measures, 99% of the time for the hippocampus, than behavioral/cognitive measures (p < 0.001). Greater consistency in MRI than behavioral/clinical measures resulted in markedly lower estimated sample size requirements for clinical trials. The estimated number of subjects per arm required to detect a 50% reduction in the rate of decline over 1 year are: AD Assessment Scale-cognitive subscale 320; Mini-Mental Status Examination 241; hippocampal volume 21; temporal horn volume 54.

CONCLUSION

The consistency of MRI measurements obtained across sites, and the consistency between the multisite milameline data and that obtained in prior single-site studies, demonstrate the technical feasibility of using structural MRI measures as a surrogate endpoint of disease progression in therapeutic trials. However, validation of imaging as a biomarker of therapeutic efficacy in AD awaits a positive trial.

Integrin expression and function on human osteoblast-like cells

The integrin family of cell adhesion molecules are a series of cell surface glycoproteins that recognize a range of cell surface and extracellular matrix (ECM)-associated ligands. To date, the precise role of individual integrin molecules in bone cell-ECM interactions remains unclear. Cell binding assays were performed to examine the ability of normal human bone cells (NHBCs) to adhere to different ECM proteins in vitro. NHBCs displayed preferential adhesion to fibronectin over collagen types I, IV, and vitronectin and showed low affinity binding to laminin and collagen type V. No binding was observed to collagen type III. The integrin heterodimers alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha v beta 3, and alpha v beta 5 were found to be constitutively expressed on the cell surface of NHBCs by flow cytometric analysis. The integrins alpha 4 beta 1 and alpha 6 beta 1 were not expressed by NHBCs. Subsequent binding studies showed that NHBC adhesion to collagen and laminin was mediated by multiple integrins where cell attachment was almost completely inhibited in the presence of a combination of function-blocking monoclonal antibodies (Mabs) to alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, and beta 1. In contrast, the adhesion of NHBCs to fibronectin was only partially inhibited (50%) in the presence of blocking Mabs to alpha 3 beta 1, alpha 5 beta 1, and beta 1. The attachment of NHBCs to collagen, laminin, fibronectin, and vitronectin was also found to be unaffected in the presence of a function-blocking Mab to alpha v beta 3. The results of this study indicate that beta 1 integrins appear to be the predominant adhesion receptor subfamily utilized by human osteoblast-like cells to adhere to collagen and laminin and in part to fibronectin.

Effects of reducing dietary saturated fatty acids on plasma lipids and lipoproteins in healthy subjects: the DELTA Study, protocol 1

Few well-controlled diet studies have investigated the effects of reducing dietary saturated fatty acid (SFA) intake in premenopausal and postmenopausal women or in blacks. We conducted a multicenter, randomized, crossover-design trial of the effects of reducing dietary SFA on plasma lipids and lipoproteins in 103 healthy adults 22 to 67 years old. There were 46 men and 57 women, of whom 26 were black, 18 were postmenopausal women, and 16 were men > or =40 years old. All meals and snacks, except Saturday dinner, were prepared and served by the research centers. The study was designed to compare three diets: an average American diet (AAD), a Step 1 diet, and a low-SFA (Low-Sat) diet. Dietary cholesterol was constant. Diet composition was validated and monitored by a central laboratory. Each diet was consumed for 8 weeks, and blood samples were obtained during weeks 5 through 8. The compositions of the three diets were as follows: AAD, 34.3% kcal fat and 15.0% kcal SFA; Step 1, 28.6% kcal fat and 9.0% kcal SFA; and Low-Sat, 25.3% kcal fat and 6.1% kcal SFA. Each diet provided approximately 275 mg cholesterol/d. Compared with AAD, plasma total cholesterol in the whole group fell 5% on Step 1 and 9% on Low-Sat. LDL cholesterol was 7% lower on Step 1 and 11% lower on Low-Sat than on the AAD (both P<.01). Similar responses were seen in each subgroup. HDL cholesterol fell 7% on Step 1 and 11% on Low-Sat (both P<.01). Reductions in HDL cholesterol were seen in all subgroups except blacks and older men. Plasma triglyceride levels increased approximately 9% between AAD and Step 1 but did not increase further from Step 1 to Low-Sat. Changes in triglyceride levels were not significant in most subgroups. Surprisingly, plasma Lp(a) concentrations increased in a stepwise fashion as SFA was reduced. In a well-controlled feeding study, stepwise reductions in SFA resulted in parallel reductions in plasma total and LDL cholesterol levels. Diet effects were remarkably similar in several subgroups of men and women and in blacks. The reductions in total and LDL cholesterol achieved in these different subgroups indicate that diet can have a significant impact on risk for atherosclerotic cardiovascular disease in the total population.

Mutations in RYR1 are a common cause of exertional myalgia and rhabdomyolysis

Mutations in the skeletal muscle ryanodine receptor (RYR1) gene are a common cause of neuromuscular disease, ranging from various congenital myopathies to the malignant hyperthermia (MH) susceptibility trait without associated weakness. We sequenced RYR1 in 39 unrelated families with rhabdomyolysis and/or exertional myalgia, frequent presentations in the neuromuscular clinic that often remain unexplained despite extensive investigations. We identified 9 heterozygous RYR1 mutations/variants in 14 families, 5 of them (p.Lys1393Arg; p.Gly2434Arg; p.Thr4288_Ala4290dup; p.Ala4295Val; and p.Arg4737Gln) previously associated with MH. Index cases presented from 3 to 45 years with rhabdomyolysis, with or without exertional myalgia (n=12), or isolated exertional myalgia (n=2). Rhabdomyolysis was commonly triggered by exercise and heat and, less frequently, viral infections, alcohol and drugs. Most cases were normally strong and had no personal MH history. Inconsistent additional features included heat intolerance, and cold-induced muscle stiffness. Muscle biopsies showed mainly subtle changes. Familial RYR1 mutations were confirmed in relatives with similar or no symptoms. These findings suggest that RYR1 mutations may account for a substantial proportion of patients presenting with unexplained rhabdomyolysis and/or exertional myalgia. Associated clinico-pathological features may be subtle and require a high degree of suspicion. Additional family studies are paramount in order to identify potentially MH susceptible relatives.

High concentrations of dexamethasone suppress the proliferation but not the differentiation or further maturation of human osteoblast precursors in vitro: relevance to glucocorticoid-induced osteoporosis

OBJECTIVE

The use of glucocorticoids (GCs) in the treatment of RA is a frequent cause of bone loss. In vitro, however, this same class of steroids has been shown to promote the recruitment and/or maturation of primitive osteogenic precursors present in the colony forming unit-fibroblastic (CFU-F) fraction of human bone and marrow. In an effort to reconcile these conflicting observations, we investigated the effects of the synthetic GC dexamethasone (Dx) on parameters of growth and osteogenic differentiation in cultures of bone marrow stromal cells derived from a large cohort of adult human donors (n=30).

METHODS

Marrow suspensions were cultured in the absence and presence of Dx at concentrations between 10 pm and 1 microm. After 28 days we determined the number and diameter of colonies formed, the total number of cells, the surface expression of receptors for selected growth factors and extracellular matrix proteins and, based on the expression of the developmental markers alkaline phosphatase (AP) and the antigen recognized by the STRO-1 monoclonal antibody, the proportion of cells undergoing osteogenic differentiation and their extent of maturation.

RESULTS

At a physiologically equivalent concentration, Dx had no effect on the adhesion of CFU-F or on their subsequent proliferation, but did promote their osteogenic differentiation and further maturation. These effects were independent of changes in the expression of the receptors for fibroblast growth factors, insulin-like growth factor 1, nerve growth factor, platelet-derived growth factors and parathyroid hormone/parathyroid hormone-related protein, but were associated with changes in the number of cells expressing the alpha(2) and alpha(4), but not beta(1), integrin subunits. At supraphysiological concentrations, the effects of Dx on the osteogenic recruitment and maturation of CFU-F and their progeny were maintained but at the expense of a decrease in cell number.

CONCLUSIONS

A decrease in the proliferation of osteogenic precursors, but not in their differentiation or maturation, is likely to be a key factor in the genesis of GC-induced bone loss.

Further characterization of cells expressing STRO-1 in cultures of adult human bone marrow stromal cells

Primitive cells of the osteoblast lineage are not well characterized but are known to be present within the STRO-1+ fraction of adult human bone and marrow. A survey of human osteosarcoma cell lines revealed that STRO-1 is expressed by MG-63 but not SaOS-2. Among murine cell lines tested, expression of STRO-1 was detected in the bipotential (adipocyte/osteoblast) line BMS-2 but not the committed osteoblast precursor MC3T3-E1. A proportion of cultured adult human bone marrow stromal cells (BMSCs) consistently expressed the STRO-1 antigen. The expression of a range of cell surface antigens was studied in relation to STRO-1 by flow cytometry and several, including the bone/liver/kidney isoform of alkaline phosphatase (ALP), were found to subtype the STRO-1+ population of BMSCs. Further, BMSCs dual-labeled with antibodies recognizing STRO-1 and ALP could be assigned to one of four fractions: STRO-1-/ALP-, STRO-1+/ALP-, STRO-1+/ALP+, and STRO-1-/ALP+. Cells from each fraction could be isolated in high purity and, when recultured, remained viable and exhibited a limited degree of phenotypic stability. Using reverse transcriptase-polymerase chain reaction, cells in the four fractions were found to express different levels of transcripts for the parathyroid hormone receptor (PTHr) and bone sialoprotein (BSP). The expression of transcripts for the nuclear transcription factor core-binding factor alpha 1/osteoblast-specific factor-2 (CBFA1/OSF2) was restricted to those fractions expressing STRO-1 and/or ALP. Treatment with 10 nM dexamethasone consistently increased the proportion of cells present in those fractions which expressed the highest levels of transcripts for PTHr and BSP (STRO-1+/ALP+ and STRO-1-/ALP+) while simultaneously decreasing the proportion present in the STRO-1+/ALP- fraction. In conclusion, the expression of STRO-1 in vitro remains a characteristic of less well differentiated cells of the osteoblast lineage; in cultures of BMSCs and in established human osteosarcoma cell lines, there is an inverse association between the expression of STRO-1 and ALP; dual labeling of BMSCs with monoclonal antibodies recognizing STRO-1 and ALP permits the identification and isolation of cells of the osteoblast lineage at different stages of differentiation.

The Pharmacy Diabetes Care Program: assessment of a community pharmacy diabetes service model in Australia

AIM

To assess the impact of a community pharmacy diabetes service model on patient outcomes in Type 2 diabetes.

METHODS

The study utilized a multisite, control vs. intervention, repeated-measures design within four states in Australia. Fifty-six community pharmacies, 28 intervention and 28 control, were randomly selected from a representative sample of urban and rural areas. Intervention pharmacies delivered a diabetes service to patients with Type 2 diabetes, which comprised an ongoing cycle of assessment, management and review, provided at regular intervals over 6 months in the pharmacy. These services included support for self monitoring of blood glucose, education, adherence support, and reminders of checks for diabetes complications. Control pharmacists assessed patients at 0 and 6 months and delivered no intervention.

RESULTS

A total of 289 subjects (149 intervention and 140 control) completed the study. For the intervention subjects, the mean blood glucose level decreased over the 6-month study from 9.4 to 8.5 mmol/l (P < 0.01). Furthermore, significantly greater improvements in glycaemic control were seen in the intervention group compared with the control: the mean reduction in HbA(1c) in the intervention group was -0.97% (95% CI: -0.8, -1.14) compared with -0.27% (95% CI: -0.15, -0.39) in the control group. Improvements were also seen in blood pressure control and quality of life in the intervention group.

CONCLUSION

A pharmacy diabetes service model resulted in significant improvements in clinical and humanistic outcomes. Thus, community pharmacists can contribute significantly to improving care and health outcomes for patients with Type 2 diabetes. Future research should focus on clarifying the most effective elements of the service model.

Kidney Single-Cell Atlas Reveals Myeloid Heterogeneity in Progression and Regression of Kidney Disease

BACKGROUND

Little is known about the roles of myeloid cell subsets in kidney injury and in the limited ability of the organ to repair itself. Characterizing these cells based only on surface markers using flow cytometry might not provide a full phenotypic picture. Defining these cells at the single-cell, transcriptomic level could reveal myeloid heterogeneity in the progression and regression of kidney disease.

METHODS

Integrated droplet- and plate-based single-cell RNA sequencing were used in the murine, reversible, unilateral ureteric obstruction model to dissect the transcriptomic landscape at the single-cell level during renal injury and the resolution of fibrosis. Paired blood exchange tracked the fate of monocytes recruited to the injured kidney.

RESULTS

A single-cell atlas of the kidney generated using transcriptomics revealed marked changes in the proportion and gene expression of renal cell types during injury and repair. Conventional flow cytometry markers would not have identified the 12 myeloid cell subsets. Monocytes recruited to the kidney early after injury rapidly adopt a proinflammatory, profibrotic phenotype that expresses Arg1, before transitioning to become Ccr2 ⁺ macrophages that accumulate in late injury. Conversely, a novel Mmp12 ⁺ macrophage subset acts during repair.

CONCLUSIONS

Complementary technologies identified novel myeloid subtypes, based on transcriptomics in single cells, that represent therapeutic targets to inhibit progression or promote regression of kidney disease.

Weekly variation in health-care quality by day and time of admission: a nationwide, registry-based, prospective cohort study of acute stroke care

BACKGROUND

Studies in many health systems have shown evidence of poorer quality health care for patients admitted on weekends or overnight than for those admitted during the week (the so-called weekend effect). We postulated that variation in quality was dependent on not only day, but also time, of admission, and aimed to describe the pattern and magnitude of variation in the quality of acute stroke care across the entire week.

METHODS

We did this nationwide, registry-based, prospective cohort study using data from the Sentinel Stroke National Audit Programme. We included all adult patients (aged >16 years) admitted to hospital with acute stroke (ischaemic or primary intracerebral haemorrhage) in England and Wales between April 1, 2013, and March 31, 2014. Our outcome measure was 30 day post-admission survival. We estimated adjusted odds ratios for 13 indicators of acute stroke-care quality by fitting multilevel multivariable regression models across 42 4-h time periods per week.

FINDINGS

The study cohort comprised 74,307 patients with acute stroke admitted to 199 hospitals. Care quality varied across the entire week, not only between weekends and weekdays, with different quality measures showing different patterns and magnitudes of temporal variation. We identified four patterns of variation: a diurnal pattern (thrombolysis, brain scan within 12 h, brain scan within 1 h, dysphagia screening), a day of the week pattern (stroke physician assessment, nurse assessment, physiotherapy, occupational therapy, and assessment of communication and swallowing by a speech and language therapist), an off-hours pattern (door-to-needle time for thrombolysis), and a flow pattern whereby quality changed sequentially across days (stroke-unit admission within 4 h). The largest magnitude of variation was for door-to-needle time within 60 min (range in quality 35-66% [16/46-232/350]; coefficient of variation 18·2). There was no difference in 30 day survival between weekends and weekdays (adjusted odds ratio 1·03, 95% CI 0·95-1·13), but patients admitted overnight on weekdays had lower odds of survival (0·90, 0·82-0·99).

INTERPRETATION

The weekend effect is a simplification, and just one of several patterns of weekly variation occurring in the quality of stroke care. Weekly variation should be further investigated in other health-care settings, and quality improvement should focus on reducing temporal variation in quality and not only the weekend effect.

FUNDING

None.

Design, synthesis, and structural analysis of influenza neuraminidase inhibitors containing pyrrolidine cores

The discovery of (+/-)-(2S,3R,4R)-2-(trifluoroacetamido)methyl-3-amino-1-(N'-ethyl-N'-isopropylcarbamyl)pyrrolidine-4-carboxylic acid (A-192558, 20e) as a potent inhibitor of influenza neuraminidase (NA) is described. Efficient syntheses of two core structures, cis-3-(allyloxycarbonyl)amino-1-(9'-fluorenylmethoxycarbonyl)pyrrolidine-4-carboxylic acid (7) and tert-butyl (+/-)-(2S,3R,4R)-2-aminomethyl-3-bis(tert-butyloxycarbonyl)amino-1-(N'-ethyl-N'-isopropylcarbamyl)pyrrolidine-4-carboxylate (18b), were developed. Starting with these core structures and using available structural information of the NA active site as the guide, analogues were synthesized in both the tri- and tetrasubstituted pyrrolidine series by means of high-throughput parallel synthesis in solid or solution phase for expeditious SAR. These studies accelerated the identification of (+/-)-(2S,3R,4R)-2-(trifluoroacetamido)methyl-3-amino-1-(N-ethyl-N-isopropylcarbamyl)pyrrolidine-4-carboxylate (20e, A-192558) as the most potent NA inhibitor in this series (IC50 = 0.2 microM against NA A and 8 microM against NA B). The X-ray crystallographic structure of A-192558 bound to NA revealed the predicted interaction of the carboxylic group with the positively charged pocket (Arg118, Arg292, Arg371) and interaction of the trifluoroacetamino residue with the hydrophobic pocket (Ile222, Trp178) of the enzyme active site. Surprisingly, the ethyl and isopropyl groups of the urea functionality induced a conformational change of Glu276, turning the Glu276/Glu277 hydrophilic pocket, which normally accommodates the triglycerol side chain of substrate sialic acid, into an induced hydrophobic pocket.

Antifungal prophylaxis in lung transplantation--a world-wide survey

While variations in antifungal prophylaxis have been previously reported in lung transplant (LTx) recipients, recent clinical practice is unknown. Our aim was to determine current antifungal prophylactic practice in LTx centers world-wide. One nominated LTx clinician from each active center was invited by e-mail to participate in a web-based survey between September 2009 and January 2010. Fifty-seven percent (58/102) responded. The majority of responses were from medical directors of LTx centers (72.4%), and from the United States (44.8%). Within the first 6 months post-LTx, most centers (58.6%) employed universal prophylaxis, with 97.1% targeting Aspergillus species. Voriconazole alone, and in combination with inhaled amphotericin B (AmB), were the preferred first-line agents. Intolerance to side effects of voriconazole (69.2%) was the main reason for switching to alternatives. Beyond 6 months post-LTx, most (51.8%) did not employ antifungal prophylaxis. Fifteen centers (26.0%) conducted routine antifungal therapeutic drug monitoring during prophylactic period. There are differences in strategies employed between U.S. and European centers. Most respondents indicated a need for antifungal prophylactic guidelines. In comparison to earlier findings, there was a major shift toward prophylaxis with voriconazole and an increased use of echinocandins, posaconazole and inhaled lipid formulation AmB.

Expression of the developmental markers STRO-1 and alkaline phosphatase in cultures of human marrow stromal cells: regulation by fibroblast growth factor (FGF)-2 and relationship to the expression of FGF receptors 1-4

Autologous marrow stromal cells have been proposed as an adjuvant in the treatment of bone defects and diseases. This will require the development of culture conditions that permit their rapid expansion ex vivo while retaining their potential for further differentiation. Fibroblast growth factor (FGF)-2 has been proposed as a candidate for the ex vivo expansion of cells with enhanced osteogenic potential, and we have explored this possibility further using cells obtained from a large cohort of adult human donors. Treatment with FGF-2 (0.001-2.5 ng/mL) had no detectable effect on colony formation, but markedly increased their proliferative potential and that of their immediate progeny, as shown by the increases in colony size and cell number. Based on the observed increase in the expression of the developmental markers STRO-1 and alkaline phosphatase (AP), a major target for the actions of FGF-2 appears to be the more primitive cells of the osteoblast lineage, and that, when added in combination with the synthetic glucocorticoid dexamethasone (Dx), it interacts positively to promote further cell maturation. The maintenance of adequate levels of ascorbate was shown to be a critical component in determining the nature of the effect of FGF-2 on AP expression. Variation in the response (predominantly in the magnitude and/or sensitivity) of the cultured cell populations to treatment with FGF-2 was apparent, but a preliminary analysis indicated that this was not due to differences in the age or gender of the donors used. The cultured cell populations were found to express multiple FGF receptors (FGFRs; 1-4) and the observed changes in the spectrum and abundance of FGFRs expressed in relation to that of STRO-1 and AP are consistent with their expression being developmentally regulated during the process of osteogenic differentiation. These results provide novel insights into the mechanism of action of FGF-2 on human cells of the osteoblast lineage and support the use of this factor, alone or in combination with Dx, for the rapid, ex vivo expansion of cell populations with enhanced osteogenic potential.

Effect on mortality of community-based maternity-care programme in rural Bangladesh

Various community-based interventions have been proposed to improve maternity care, but hardly any studies have reported the effect of these measures on maternal mortality. In this study, the efficacy of a maternity-care programme to reduce maternal mortality has been evaluated in the context of a primary health-care project in rural Bangladesh. Trained midwives were posted in villages, and asked to attend as many home-deliveries as possible, detect and manage obstetric complications at onset, and accompany patients requiring referral for higher-level care to the project central maternity clinic. The effect of the programme was evaluated by comparison of direct obstetric maternal mortality ratios between the programme area and a neighbouring control area without midwives. Random assignment of the intervention was not possible but potentially confounding characteristics, including coverage and use of other health and family planning services, were similar in both areas. Maternal mortality ratios due to obstetric complications were similar in both areas during the 3 years preceding the start of the programme. By contrast, during the following 3 years, the ratio was significantly lower in the programme than in the control area (1.4 vs 3.8 per 1000 live births, p = 0.02). The findings suggest that maternal survival can be improved by the posting of midwives at village level, if they are given proper training, means, supervision, and back-up. The inputs for such a programme to succeed and the constraints of its replication on a large scale should not be underestimated.

Structure of a secreted aspartic protease from C. albicans complexed with a potent inhibitor: implications for the design of antifungal agents

The three-dimensional structure of a secreted aspartic protease from Candida albicans complexed with a potent inhibitor reveals variations on the classical aspartic protease theme that dramatically alter the specificity of this class of enzymes. The structure presents: (1) an 8-residue insertion near the first disulfide (Cys 45-Cys 50, pepsin numbering) that results in a broad flap extending toward the active site; (2) a 7-residue deletion replacing helix hN2 (Ser 110-Tyr 114), which enlarges the S3 pocket; (3) a short polar connection between the two rigid body domains that alters their relative orientation and provides certain specificity; and (4) an ordered 11-residue addition at the carboxy terminus. The inhibitor binds in an extended conformation and presents a branched structure at the P3 position. The implications of these findings for the design of potent antifungal agents are discussed.

A prospective study of real-time panfungal PCR for the early diagnosis of invasive fungal infection in haemato-oncology patients

A blinded prospective study was performed to determine whether screening of whole blood using a real-time, panfungal polymerase chain reaction (PCR) technique could predict the development of invasive fungal infection (IFI) in immunocompromised haemato-oncology patients. In all, 78 patients (125 treatment episodes) were screened twice weekly by real-time panfungal PCR using LightCyclertrade mark technology. IFI was documented in 19 treatment episodes (five proven, three probable and 11 possible), and in 12, PCR was sequentially positive. PCR positivity occurred in: 4/5 proven; 2/3 probable; 6/11 possible; and 29/106 with no IFI. In 8/12 with IFI and sequentially positive PCR results, PCR positivity occurred before (median 19.5 days) and in 4/12 (median 10.5 days) after the initiation of empirical antifungal therapy. Based on sequential positive results for proven/probable IFI sensitivity, specificity, positive predictive value and negative predictive value were 75, 70, 15 and 98%, respectively. Real-time panfungal PCR is a sensitive tool for the early diagnosis of IFI in immunocompromised haemato-oncology patients. It may be most useful as a screening method in high-risk patients, either to direct early pre-emptive antifungal therapy or to determine when empirical antifungal therapy can be withheld in patients with antibiotic--resistant neutropenic fever. However, these strategies require further assessment in comparative clinical trials.

Species variation in dopamine receptor binding

Binding of 3H-spiroperidol, 3H-apomorphine and 3H-ADTN (2-amino-6,7-dihydroxytetrahydronaphthalene) associated with dopamine receptors has been evaluated in corpus striatal membranes of calf, rat and human brains. Substantial species differences are apparent for numberous agonists and antagonists in competing for receptor binding. In general, dopamine receptor antagonists are more potent in rat and agonists more potent in calf. In competing for 3H-spiroperidol binding sulpiride, molindone and metaclopramide show the most pronounced species differences, being 3--10 times more potent in rat and human than in calf. In all three species agonists compete for 3H-spiroperidol binding with Hill coefficients less than one while antagonists inhibit 3H-spiroperidol binding with Hill coefficients of about 1.0. Conversely, 3H-apomorphine and 3H-ADTN binding in all three species is inhibited by antagonists with Hill coefficients less than 1.0 while agonists display Hill coefficients of about 1.0. In general agonists are more potent in competing for binding of 3H-apomorphine and 3H-ADTN than 3H-spiroperidol. However, a small component of dopamine, apomorphine and ADTN inhibition of 3H-spiroperidol binding displays very high affinity (IC50 about 1 nM). In human amygdala 3H-spiroperidol appears to label serotonin receptors predominantly.

Replication of scrapie in spleens of SCID mice follows reconstitution with wild-type mouse bone marrow

SCID mice are resistant to intraperitoneal infection with 10(3) and 10(4) intracerebral ID50 units of ME7 scrapie agent whereas they develop disease after intracerebral challenge. However, higher doses introduced, by intraperitoneal or subcutaneous routes, produce disease. Immunocompetent mice of the same strain (CB20) developed scrapie following either intracerebral or intraperitoneal infection. Bioassay of spleens from SCID mice infected with 10(-1) dilutions of ME7 scrapie by intraperitoneal, intracerebral or abdominal subcutaneous injection showed traces or low levels of infectivity in spleen. However, subcutaneous injection beneath the skin of the neck failed to infect the spleen. CB20 bone marrow reconstitution of SCID mice resulted in the regeneration of a normal lymphoid architecture in the spleen. Spleens from these reconstituted mice, infected intracerebrally with a 10(-1) dilution of ME7 contained high levels of infectivity. These results suggest that the ability to replicate scrapie agent in spleen or lymphoid tissue depends on the restoration of normal lymphoid structure and in particular the presence of differentiated follicular dendritic cells. The possibility that SCID mice can select minor strains of scrapie which are normally unrecognized in cloned ME7 is discussed.

Stress, song and survival in sparrows

The stress response--increases in circulating glucocorticoids following a stressor--is typically considered adaptive, but few studies address the fitness consequences of individual variation in stress response. Generally, due to negative consequences of prolonged elevation of glucocorticoids, animals should have a transient stress response just sufficient to cope with the stressor. In rodents, stress responsiveness is affected by early developmental experience, and hyper-responsiveness to stress is linked to morbidity and mortality. We assessed individual variation in stress responses in free-living song sparrows, Melospiza melodia, in relation to fitness-related measures including song and overwinter survival. Birds with greater increases in corticosterone 30 min following restraint stress were less likely to return to breed the following year. Stress responsiveness was also correlated with song complexity: males with fewer syllables in their song repertoires had greater stress reactivity. Our findings support the hypothesis that developmental stressors both impair song development and affect the adult stress response. Thus, individual variation in the stress response may relate to variation in fitness.

Single-cell RNA sequencing profiling of mouse endothelial cells in response to pulmonary arterial hypertension

AIMS

Endothelial cell (EC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension (PAH). We aimed to characterize EC dynamics in PAH at single-cell resolution.

METHODS AND RESULTS

We carried out single-cell RNA sequencing (scRNA-seq) of lung ECs isolated from an EC lineage-tracing mouse model in Control and SU5416/hypoxia-induced PAH conditions. EC populations corresponding to distinct lung vessel types, including two discrete capillary populations, were identified in both Control and PAH mice. Differential gene expression analysis revealed global PAH-induced EC changes that were confirmed by bulk RNA-seq. This included upregulation of the major histocompatibility complex class II pathway, supporting a role for ECs in the inflammatory response in PAH. We also identified a PAH response specific to the second capillary EC population including upregulation of genes involved in cell death, cell motility, and angiogenesis. Interestingly, four genes with genetic variants associated with PAH were dysregulated in mouse ECs in PAH. To compare relevance across PAH models and species, we performed a detailed analysis of EC heterogeneity and response to PAH in rats and humans through whole-lung PAH scRNA-seq datasets, revealing that 51% of up-regulated mouse genes were also up-regulated in rat or human PAH. We identified promising new candidates to target endothelial dysfunction including CD74, the knockdown of which regulates EC proliferation and barrier integrity in vitro. Finally, with an in silico cell ordering approach, we identified zonation-dependent changes across the arteriovenous axis in mouse PAH and showed upregulation of the Serine/threonine-protein kinase Sgk1 at the junction between the macro- and microvasculature.

CONCLUSION

This study uncovers PAH-induced EC transcriptomic changes at a high resolution, revealing novel targets for potential therapeutic candidate development.