“Nanocasting”: Using SBA-15 Silicas as Hard Templates to Obtain Ultrasmall Monodispersed γ-Fe2O3 Nanoparticles

This work describes the use of mesoporous SBA-15 silicas as hard templates for the size-controlled synthesis of oxide nanoparticles, with the pores acting as nanoscale reactors. This fundamental work is mainly aimed at understanding unresolved issues concerning the occurrence and size dependence of phase transitions in oxide nanocrystals. Aqueous solutions of Fe(NO3)3*9H2O are deposited inside the pores of SBA-15 silicas with mesopore diameters of 4.3, 6.6, and 9.5 nm. By calcination, the nitrate salt transforms into FeOx oxides. The XRD peaks of nanocrystals are broad and overlapping, resulting in ambiguities attributed to a given allotropic variety of Fe2O3 (alpha, epsilon, or gamma) or Fe3O4. The association of XRD, SAED, and Raman information is necessary to solve these ambiguities. The metastable gamma-Fe2O3 variety is selectively formed at low Fe/Si atomic ratio (ca. 0.20) and when a low calcination temperature is used (773 or 873 K followed by quenching to room temperature once the targeted temperature is reached). The small size dispersion of the patterned nanoparticles, suggested on a local scale by TEM, is confirmed statistically by magnetic measurements. The nanoparticles have a superparamagnetic behavior around room temperature. Their magnetic moments (from 220 to 370 mB), their sizes (from 4.0 to 4.8 nm), and their blocking temperatures (from 36 to 58 K) increase with the silica template mesopore diameter. Their magnetic properties are compared to those of standard gamma-Fe2O3 nanoparticles of similar size, obtained by coprecipitation in water and stabilized by a citrate coating.

Evaluation of a model for maximizing interprofessional education in an acute hospital

A one-year planning phase established a rolling programme of bi-monthly interprofessional clinical teaching workshops derived directly from patient experiences in an acute hospital. Pre-registration healthcare students from 8 professions spent an afternoon in the hospital training centre, randomly allocated to one of 6-8 small working groups. Using a problem-based methodology they analysed a ward case with patient consent, chosen to reflect the input of a wide range of health professionals. Students worked through a prepared workbook facilitated by a range of tutors from all disciplines. Each small group reported back on one aspect of team working to the entire cohort entering into debate and discussion with the support of clinical and academic tutors. Post course patient details were found on a website enabling students to progress their uni-professional knowledge, e.g., on anatomy, physiology, pharmacology etc. The questionnaire evaluation on over 126 students and 11 tutors identified that interprofessional competencies were understood and valued. Students related principles of team working and collaborative practice to their placement experiences of team work. Interactive learning enables further appreciation of professions roles and responsibilities and the importance of teamwork to optimize patient care (82.0 - 90.5%). The half-day learning model can be easily supported by busy clinical staff, led by hospital educators and accessed by students on hospital placements, at a mid-point in training, with learning supported by consenting in-patients or recent admissions prepared to share their experiences.

Block and tackle: CTLA4Ig takes on lupus

Blockade of antigen nonspecific costimulatory signals is a promising approach for the treatment of autoimmune diseases including systemic lupus erythematosus (SLE). CTLA4Ig, an antagonist of the CD28/B7 costimulatory interaction, effectively prevents SLE onset in several murine models and, when used in combination with cyclophosphamide, can induce remission of active SLE nephritis. In this review we describe the known mechanisms of action of CTLA4Ig both in normal immunity and in autoimmune disease models and address issues about its activity that still need to be resolved. We discuss the preclinical use of CTLA4Ig in murine SLE models and the rationale for a clinical trial in SLE patients.

Ultrasound for central venous cannulation: economic evaluation of cost-effectiveness

We compared the economics of using two-dimensional ultrasound locating devices and more traditional landmark methods for central venous cannulation in the National Health Service (NHS). The evaluation consisted of a systematic review of randomised controlled trials and an economic evaluation using decision analytic cost-effectiveness modelling. Incremental costs per complication avoided associated with landmark and ultrasound central venous cannulation were modelled for patients scheduled for central venous cannulation. The marginal economic cost of using ultrasound for central venous cannulation was less than 10 pounds sterling per procedure, assuming that a machine is used for 15 procedures each week. The base case scenario implied that 2000 pounds sterling worth of resource savings result for every 1000 procedures undertaken and 90 avoided complications. Sensitivity analysis indicated that the results of modelling appear robust to the central assumptions used. Ultrasound guidance used in central venous cannulation procedures saves NHS resources even with conservative modelling assumptions.

Lowering anti-dsDNA antibodies--what's new?

Antibodies to dsDNA are specific to SLE and are pathogenic, both due to their ability to deposit in tissues through a variety of mechanisms, and to their ability, when present in immune complexes, to activate inflammatory cells. The relationship of serum anti-dsDNA antibody levels to disease activity is a complex one and the factors that determine whether or not such antibodies will be pathogenic in an individual SLE patient are incompletely understood. Although anti-dsDNA antibodies can be made by naïve B cells and B cells belonging to the B1 and marginal zone subsets, pathogenic anti-dsDNA antibodies have the hallmarks of germinal center development and exposure to T cell help, including accumulation of somatic mutations and class switching to the IgG isotype. Epitope spreading may result in aquisition of cross-reactivities with multiple target organ antigens and aquisition of a memory phenotype will allow these B cells to acquire antigen presentation functions that amplify the autoreactive response. In the early stages of disease, or after remission induction protocols, autoreactive B cells may be susceptible to treatments that target T cell costimulation or that deplete or tolerize naïve and mature B cells. Therapeutic approaches targeting innate immune responses or regulatory T cells are starting to be tested in pre-clinical models. In later disease stages, memory and plasma cell accumulation may render patients more resistant to this type of therapeutic approach. Deposition of anti-dsDNA antibodies in target tissues can stimulate an inflammatory cascade that leads to tissue damage. A number of murine models have now been developed that show that interruption of this cascade can prevent or reverse such damage. This type of approach may be beneficial for individuals with established disease. As we learn more about the specific defects that cause SLE, it may become possible to individualize therapy based on patient specific biologic markers.

EVE/cyclosporin (etoposide, vincristine, epirubicin with high-dose cyclosporin)-chemotherapy selected for multidrug resistance modulation

Sixteen children and young adults were treated with high-dose cyclosporin combined with a combination of cytotoxics (epirubicin, vincristine and etoposide) (EVE) known to be influenced by P-glycoprotein-mediated multidrug resistance (MDR). Tumour types were neuroblastoma 3, Ewing's sarcoma 2, rhabdomyosarcoma 5, osteosarcoma 3, desmoplastic small round cell tumour 1, nephroblastoma 1, T-acute lymphoblastic leukaemia (ALL) 1. All had progressed or relapsed following at least two of the drug types included in EVE. Acute reactions to cyclosporin and myelosuppression were the major toxicities documented. Renal and hepatic toxicity was rarely severe and always transient. Partial responses (PR) were observed in 2 patients (1 rhabdomyosarcoma, 1 Ewing's sarcoma). We conclude that this combination is tolerable in heavily pretreated patients and may be suitable for further evaluation in untreated poor risk tumours.

Identification of Candida glabrata by a 30-second trehalase test

Rapid (30-s) trehalase tests done with material from colonies of 482 yeasts suspended in a drop of trehalose solution on a commercially supplied glucose test strip were positive for 225 (99.1%) of 227 Candida glabrata isolates grown on either of two differential media, Candida ID medium or CandiSelect medium. The test was positive for only 3 (1.2%) and 12 (4.7%) of 255 isolates of other medically important yeast species grown on the same two media, respectively. A rapid maltase test done with a subset of 255 yeast isolates was negative for all but 1 of 64 trehalase-positive C. glabrata isolates, raising the specificity of the rapid testing for C. glabrata to 98.4 to 100%, depending on the isolation medium used. Rapid trehalase and maltase tests done independently in two laboratories with 217 yeast isolates showed sensitivities of 96.0 to 98.0% and specificities of 98.2 to 99.4% for identification of C. glabrata from colonies grown on Candida ID medium. The specificity was much lower because of frequent false-positive trehalose test results when the source of colonies was Sabouraud agar formulated with 4% glucose. We conclude that direct recognition of C. albicans as blue colonies on Candida ID isolation medium coupled with the performance of the 30-s trehalase and maltase tests for C. glabrata among the white colonies on this medium will allow the rapid presumptive identification of the two yeast species most commonly encountered in clinical samples.

A non-immunogenic adenoviral vector, coexpressing CTLA4Ig and bilirubin-uridine-diphosphoglucuronateglucuronosyltransferase permits long-term, repeatable transgene expression in the Gunn rat model of Crigler-Najjar syndrome

Host immune responses limit the duration of expression of transgenes introduced by recombinant adenoviruses, preclude gene transfer upon vector readministration and cause liver injury. CTLA4Ig inhibits immune response by blocking the co-stimulatory interaction between CD28 on T cells and B7 on antigen-presenting cells. We have constructed a recombinant adenovirus, Ad-hUGT1A1-CTLA4Ig that coexpresses human bilirubin-uridinediphosphoglucuronate glucuronosyltransferase (hUGT1A1) and soluble murine CTLA4Ig, both driven by CMV immediate-early promoters. After intravenous injection of this vector (6 x 10(11) p.f.u.) into UGT1A1-deficient jaundiced Gunn rats, serum CTLA4Ig levels peaked at 1.8-2.0 mg/ml on day 7 and declined thereafter to 0.2 mg/ml by day 180. Serum bilirubin declined from mean preinjection levels of 8.0 mg/dl to 0.48-0.6 mg/dl in 3 days, remained normal for 28 weeks, and then gradually increased to 8 mg/dl by day 350. A second injection of Ad-hUGT1A1-CTLA4Ig normalized serum bilirubin. In two rats in this group that were followed longer, serum bilirubin increased to 3.1 and 3.5 mg/dl in 40 weeks, but was normalized again after a third injection. The antibody and cytotoxic lymphocyte (CTL) responses were negligible, and liver biopsy showed no inflammatory cell infiltration. Rats receiving a tertiary challenge with Ad-LacZ (expressing E. coli beta-galactosidase) (5 x 10(11) p.f.u.), 2 months after the second dose of Ad-hUGT1A1-CTLA4Ig, showed beta-galactosidase expression in over 80% of hepatocytes. In contrast, after Ad-hUGT1A1 (which expresses UGT1A1 alone) injection, serum bilirubin remained normal for only 4 weeks, and returned to preinjection levels by day 120. Bilirubin levels did not decline upon reinjection, and beta-galactosidase was not expressed after Ad-LacZ. High levels of adenovirus-specific antibodies and CTL, and hepatic inflammation were found. This is the first demonstration that coexpression of CTLA4Ig permits prolonged expression and repeatable gene transfer by an adenoviral vector.

Allele frequencies of nine STR loci of Jewish and Arab populations in Israel

DNA typing of nine short tandem repeat (STR) loci was carried out on unrelated Israeli Jewish and Arab individuals. All loci were highly polymorphic and the distribution of the obtained genotypes did not deviate from Hardy-Weinberg equilibrium. A comparison between Jewish and Arab population data revealed statistically significant differences in allele frequency distributions for some of the loci. The results presented in this study enable the use of these nine STR loci for forensic, identification and paternity cases in the Jewish and the Arab populations of Israel.

HIV-infected American Indians/Alaska natives in the Western United States

OBJECTIVE

We sought to describe HIV-infected American Indians/Alaska Natives (AI/ AN) in the western United States.

DESIGN

One hundred fifty-one Al/AN and 11,344 non-AI/AN HIV-infected patients in Seattle, Denver, and Los Angeles were followed by medical record review from January 1989 through June 1998 for the Adult/Adolescent Spectrum of HIV-related Diseases study.

METHODS

Bivariate and multivariate statistical analyses comparing HIV-infected Al/AN and non-AI/AN were performed.

RESULTS

There were 103 (68%) male and 48 (32%) female Al/AN patients, while non-Al/AN patients were 86% male and 14% female (P<.001). The median age among AI/ AN was 32 years vs. 34 years among non-AI/AN (P = .05). Male Al/AN were more likely than male non-AI/AN to report the dual risks of having sex with men and injection drug use (32% vs. 14%; P<.001) compared with other HIV risks. Median CD4 cell counts were higher in Al/AN than in non-AI/AN (P< or =.001). AI/AN were more likely to be diagnosed with an acute sexually transmitted disease (STD) than were non-AI/AN (11% vs. 4%, P<.001). Five (6%) of AI/AN with AIDS had active pulmonary tuberculosis (TB) compared with 132 (2%) of non-AI/AN with AIDS (P = .02). While 52% of Al/AN and 44% of non-AI/AN had a psychiatric illness (P = .04), and 13% of AI/AN, and 6% of non-AI/ AN had suicidal ideation (P<.001), these associations became non-significant in analyses stratified by alcohol and drug use (P>.05). In adjusted models, survival and progression to opportunistic infection or CD4 cell count less than 200/mm3 did not significantly differ between Al/AN and non-AI/AN.

CONCLUSIONS

HIV-infected AI/AN were younger than non-AI/AN, and a greater proportion of Al/AN were women relative to non-AI/AN. AI/AN were more likely to be diagnosed with STDs and TB. In adjusted models, their risks of death and developing AIDS did not significantly differ from those of non-AI/AN.

Drosophila-raf acts to elaborate dorsoventral pattern in the ectoderm of developing embryos

In the early Drosophila embryo the activity of the EGF-receptor (Egfr) is required to instruct cells to adopt a ventral neuroectodermal fate. Using a gain-of-function mutation we showed that D-raf acts to transmit this and other late-acting embryonic Egfr signals. A novel role for D-raf was also identified in lateral cell development using partial loss-of-function D-raf mutations. Thus, we provide evidence that zygotic D-raf acts to specify cell fates in two distinct pathways that generate dorsoventral pattern within the ectoderm. These functional requirements for D-raf activity occur subsequent to its maternal role in organizing the anterioposterior axis. The consequences of eliminating key D-raf regulatory domains and specific serine residues in the transmission of Egfr and lateral epidermal signals were also addressed here.