HREM of the {111} surfaces of iron oxide nanoparticles

Mixed phase Fe3O4-gamma-Fe2O3 (magnetite-maghemite) iron oxide nanoparticles have been fabricated by colloidal routes. HRTEM/HRSTEM images of the nanoparticles show the presence of [111] facets that terminate with enhanced contrast, which is shown to be caused by the presence of additional cations at the edges of the nanoparticles. HRTEM images were taken on a FEI CM200 FEGTEM, a JEOL 3100 with a LaB6 source, and a double aberration corrected JEOL-JEM 2200FS FEGTEM. The enhanced contrast effect was observed on the [111] surface atomic layers resolved using each machine. HRSTEM images, taken on an aberration corrected STEM, resolved enhanced contrast at specific surface sites. Exit wave reconstruction was also carried out on focal series taken on a double aberration corrected JEOL-JEM 2200FS and showed similar highly resolved enhanced contrast at specific surface cation sites. It is apparent that additional cations are occupying the [111] terminating layers of these nanoparticle surfaces. The use of different microscopes and techniques in this paper provides strong evidence that the enhanced contrast is a real effect and not an effect caused by microscope aberrations.

The assessment of hookworm calreticulin as a potential vaccine for necatoriasis

A vaccine against the human hookworm Necator americanus is urgently required to reduce hookworm-induced morbidity in endemic areas. In the present study, recombinant hookworm calreticulin, a nominated vaccine candidate, has been tested in mice. Mice given calreticulin had 43-49% fewer worms in their lungs, compared to non-vaccinated controls, following challenge infection with infective hookworm larvae. These levels of protection were achieved in the absence of adjuvant following intraperitoneal administration of three doses of 15 microg antigen. Antigen was also encapsulated in PLG microparticles. Encapsulated calreticulin elicited higher levels of anti-calreticulin IgG1 than free antigen but failed to induce protective immunity. The protection induced by free calreticulin was associated with low levels of serum IgE and moderate lung eosinophilia whilst administration of calreticulin-loaded microparticles was associated with high levels of serum IgE and higher lung eosinophil activity, suggesting that the classical Th2 phenotype may not always be associated with protective immunity, albeit in experimental necatoriasis.

Degradation of extracellular matrix components by defined proteinases from the greenbottle larva Lucilia sericata used for the clinical debridement of non-healing wounds

BACKGROUND

Larvae of the greenbottle fly Lucilia sericata are used routinely for the clinical treatment of difficult necrotic and infected wounds. Degradation by proteinases contained in larval excretory/secretory (ES) products is thought to contribute to wound debridement by removal of dead tissue. However, proteinase activity may also affect host tissue remodelling processes.

OBJECTIVES

To identify proteolytic enzymes derived from L. sericata ES products with activities against fibrin and extracellular matrix (ECM) components.

METHODS

Larval proteinase activities were assayed in vitro using class-specific substrates and inhibitors. Their action against fibrin and ECM components was examined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

RESULTS

Three classes of proteolytic enzyme were detected in the secretions using fluorescein isothiocyanate-labelled casein as a model substrate. The predominant activity belonged to serine proteinases (pH optima 8-9) of two different subclasses (trypsin-like and chymotrypsin-like), with a weaker aspartyl proteinase (pH 5) and a metalloproteinase (pH 9) with exopeptidase characteristics also present. Using skin-relevant ECM components as substrates L. sericata ES products solubilized fibrin clots and degraded fibronectin, laminin and acid-solubilized collagen types I and III. Hydrolysis of ECM macromolecules was inhibited by preincubating ES products with phenylmethylsulphonyl fluoride but not 4-amidinophenylmethylsulphonyl fluoride, indicating that degradation was due to the 'chymotrypsin-like' serine proteinase.

CONCLUSIONS

These data suggest that a combination of L. sericata ES proteinases involving chymotrypsin-like and trypsin-like activities could potentially influence wound healing events when maggots are introduced into necrotic and infected wounds, with the chymotrypsin-like activity involved in the remodelling of ECM components.

A phylogenetic analysis of Diurideae (Orchidaceae) based on plastid DNA sequence data

DNA sequence data from plastid matK and trnL-F regions were used in phylogenetic analyses of Diurideae, which indicate that Diurideae are not monophyletic as currently delimited. However, if Chloraeinae and Pterostylidinae are excluded from Diurideae, the remaining subtribes form a well-supported, monophyletic group that is sister to a "spiranthid" clade. Chloraea, Gavilea, and Megastylis pro parte (Chloraeinae) are all placed among the spiranthid orchids and form a grade with Pterostylis leading to a monophyletic Cranichideae. Codonorchis, previously included among Chloraeinae, is sister to Orchideae. Within the more narrowly delimited Diurideae two major lineages are apparent. One includes Diuridinae, Cryptostylidinae, Thelymitrinae, and an expanded Drakaeinae; the other includes Caladeniinae s.s., Prasophyllinae, and Acianthinae. The achlorophyllous subtribe Rhizanthellinae is a member of Diurideae, but its placement is otherwise uncertain. The sequence-based trees indicate that some morphological characters used in previous classifications, such as subterranean storage organs, anther position, growth habit, fungal symbionts, and pollination syndromes have more complex evolutionary histories than previously hypothesized. Treatments based upon these characters have produced conflicting classifications, and molecular data offer a tool for reevaluating these phylogenetic hypotheses.

"Titicut follow-up": successful transfer of assaultive patients from a high security facility to a less restrictive setting

Currently many state mental health agencies are redoubling their efforts to close or downsize state hospitals and place their populations in less restrictive settings. Prior to 1990, certain assaultive non-criminal male patients from public facilities operated by the Massachusetts Department of Mental Health (DMH) could be transferred to prison psychiatric facilities operated by the Department of Corrections (DOC). In 1989 that practice was declared illegal, and clients so placed were ordered returned to DMH facilities. This case study describes the liaison process by which patients remaining in the DOC facility returned to DMH facilities, describes their subsequent hospital course, and reviews the validity of policy assumptions made about these patients' needs in the context of this follow-up data. The results of this analysis indicate that many fewer patients in this group of primarily chronic schizophrenic men required a secure facility upon their return than was previously assumed.

Identification of a novel low-temperature-response element in the promoter of the barley (Hordeum vulgare L) gene blt101.1

Two winter barley (Hordeum vulgare L. cv. Igri) genomic clones, lambda gblt101.1 and lambda gblt101.2, encoding the blt101 gene family, were isolated from a genomic library. Deletion analysis of the blt101.1 promoter, using transient beta-glucuronidase (GUS) reporter expression assays, indicated that it contains at least three regulatory regions. A 107-bp region between nucleotides -168 and -275 with respect to the translation initiation codon, confers high-level GUS reporter expression at low temperature and contains a sequence (designated CR1) that is highly conserved in equivalent positions within the promoters of both members of the blt101 gene family. A 10-bp motif contained within CR1 binds proteins present in nuclear extracts from both control and low-temperature-treated barley tissue. Loss-of-function experiments, using transient-expression analysis, confirmed that this motif acts as a previously unreported low-temperature-responsive element. Nuclease sensitivity analysis of intact chromatin indicated that the blt101.1 promoter becomes more susceptible to DNase and micrococcal nuclease at low temperature, consistent with chromatin reorganisation upon transcriptional induction. It is proposed that both the 10-bp motif and chromatin reorganisation are involved in the regulation of blt101.1 at low temperature. This is the first detailed analysis of a low-temperature-specific plant promoter and identifies a novel low-temperature-response element.

Ascaris suum-derived products induce human neutrophil activation via a G protein-coupled receptor that interacts with the interleukin-8 receptor pathway

Infection with tissue-migrating helminths is frequently associated with intense granulocyte infiltrations. Several host-derived factors are known to mediate granulocyte recruitment to the tissues, but less attention has been paid to how parasite-derived products trigger this process. Parasite-derived chemotactic factors which selectively recruit granulocytes have been described, but nothing is known about which cellular receptors respond to these agents. The effect of products from the nematodes Ascaris suum, Toxocara canis, and Anisakis simplex on human neutrophils were studied. We monitored four parameters of activation: chemotaxis, cell polarization, intracellular Ca(2+) transients, and priming of superoxide anion production. Body fluids of A. suum (ABF) and T. canis (TcBF) induced strong directional migration, shape change, and intracellular Ca(2+) transients. ABF also primed neutrophils for production of superoxide anions. Calcium mobilization in response to A. suum-derived products was completely abrogated by pretreatment with pertussis toxin, implicating a classical G protein-coupled receptor mechanism in the response to ABF. Moreover, pretreatment with interleukin-8 (IL-8) completely abrogated the response to ABF, demonstrating desensitization of a common pathway. However, ABF was unable to fully desensitize the response to IL-8, and binding to CXCR1 or CXCR2 was excluded in experiments using RBL-2H3 cells transfected with the two human IL-8 receptors. Our results provide the first evidence for a direct interaction between a parasite-derived chemotactic factor and the host's chemotactic network, via a novel G protein-coupled receptor which interacts with the IL-8 receptor pathway.

The OMENS trial: opportunistic evaluation of musculo-skeletal physician care among orthopaedic outpatients unlikely to require surgery

STUDY OBJECTIVE

For orthopaedic outpatients judged as unlikely to require surgery, how does the cost-effectiveness of treatment from a musculo-skeletal medicine physician compare with that of a conventional orthopaedic surgeon-led service?

DESIGN

Partially randomised, pragmatic trial comparing management from a single musculo-skeletal medicine physician with orthopaedic surgeon-led management, with the timing and nature of treatments at the discretion of individual clinicians. Main outcomes were: change in patient reported health (SF-36 and EuroQol), and marginal health service costs.

SETTING

Outpatient department of an Edinburgh orthopaedic hospital.

SUBJECTS

One thousand three hundred and twenty six people; aged over 18, referred to and later attending the outpatient department with a 'non-surgical' musculo-skeletal condition, who provided baseline information. Eight hundred and twenty nine were randomly allocated to management by either the musculo-skeletal medicine physician (medical group) or a conventional orthopaedic surgeon-led service (surgical group); 497 were assigned to the treatment groups according to their general practitioner's preference.

RESULTS

There are aspects of the study design concerning statistical power, potential selection bias and generalisability, which mean that any results must be treated with caution. Although there was no statistically significant difference in health gain between the randomly allocated groups (with similar findings in the non-randomised medical and surgical groups), the patient groups were heterogeneous and the confidence intervals did not rule out clinically important differences. The medical group received more outpatient treatment, 20% vs. 10% (difference 95% CI 5% to 15%) with a higher rate of physiotherapy referral, 45% vs. 30% (15%, 9% to 22%). The surgical group received more inpatient surgical care 6% vs. 17% (-11%, -15% to -7%). Mean healthcare costs in the medical group were 179 Pounds per patient compared with 287 Pounds in the surgical group (-108 Pounds, -25 Pounds to -191 Pounds).

CONCLUSIONS

Interpretation should take into account the practical difficulties and circumstances of the study. Although no differences in health gain were found between these two management policies for 'non-surgical' orthopaedic outpatients, the trial was less statistically powerful than planned and the confidence intervals included clinically important differences. Differences in treatment emphasis gave estimated costs savings to the Health Service of 108 Pounds per patient treated by the musculo-skeletal medicine service.

Targeted histone acetylation and altered nuclease accessibility over short regions of the pea plastocyanin gene

The chromatin structure of the pea plastocyanin gene (PetE) was examined at three different transcriptional states by investigating the acetylation states of histones H3 and H4 and the nuclease accessibility of the gene in pea roots, etiolated shoots, and green shoots. The acetylation states of histones associated with different regions of PetE were analyzed by chromatin immunoprecipitation with antibodies specific for acetylated or nonacetylated histone H3 or H4 tails, followed by polymerase chain reaction quantification. Comparison of pea tissues indicated that histone hyperacetylation was associated with increased PetE transcription in green shoots. Moreover, hyperacetylation of both histones H3 and H4 was targeted to the enhancer/promoter region in green shoots, suggesting that only specific nucleosomes along the gene were modified. Time-course digestions of nuclei with micrococcal nuclease and DNaseI indicated that the enhancer/promoter region was more resistant to digestion in the inactive gene in pea roots than was the same region in the active gene in shoots, whereas the transcribed region of PetE was digested similarly among the tissues. This finding indicates that transcription is accompanied by changes in the nuclease accessibility of the enhancer/promoter region only. Moreover, these results indicate that the changes in nuclease accessibility are organ specific, whereas histone hyperacetylation is light dependent, and they suggest that changes in nuclease accessibility precede histone hyperacetylation during PetE activation.

Targeted histone acetylation and altered nuclease accessibility over short regions of the pea plastocyanin gene

The chromatin structure of the pea plastocyanin gene (PetE) was examined at three different transcriptional states by investigating the acetylation states of histones H3 and H4 and the nuclease accessibility of the gene in pea roots, etiolated shoots, and green shoots. The acetylation states of histones associated with different regions of PetE were analyzed by chromatin immunoprecipitation with antibodies specific for acetylated or nonacetylated histone H3 or H4 tails, followed by polymerase chain reaction quantification. Comparison of pea tissues indicated that histone hyperacetylation was associated with increased PetE transcription in green shoots. Moreover, hyperacetylation of both histones H3 and H4 was targeted to the enhancer/promoter region in green shoots, suggesting that only specific nucleosomes along the gene were modified. Time-course digestions of nuclei with micrococcal nuclease and DNaseI indicated that the enhancer/promoter region was more resistant to digestion in the inactive gene in pea roots than was the same region in the active gene in shoots, whereas the transcribed region of PetE was digested similarly among the tissues. This finding indicates that transcription is accompanied by changes in the nuclease accessibility of the enhancer/promoter region only. Moreover, these results indicate that the changes in nuclease accessibility are organ specific, whereas histone hyperacetylation is light dependent, and they suggest that changes in nuclease accessibility precede histone hyperacetylation during PetE activation.

Limnanthes douglasii erucic acid-specific lysophospatidic acid acyltransferase activity in oilseed rape: an analysis of biochemical effects

It has been shown previously that erucic acid accumulates in the sn-2 position of triglycerides after introduction of a Limnanthes lysophosphatidic acid acyltransferase. However, in none of the studies to date has a proper evaluation been made of the relationship between transgene expression and the erucic acid accumulation at sn-2. One of the necessary tools to study the variability is the presence of a specific antibody raised against the introduced acyltransferase. In the present study, we have looked at the correlation between erucic acid accumulation at sn-2, production of trierucin and the expression of the transgene, as detected by Western blotting. The data presented include comparisons of progeny of individual lines grown under various conditions and at various times, and an analysis of a number of lines during development. We also present calculations that could indicate from which position the erucic acid found at position sn-2 is derived.

Outcome of reduction mammaplasty--a patients' perspective

There have been several studies analysing the outcome of reduction mammaplasty in the literature. Our study is condition specific, with emphasis placed on the patients' subjective experience of treatment. Following a successful pilot study, data were obtained from 74 patients' charts and an anonymous postal questionnaire over a 1-year period. Sixty-six returned the questionnaire complete (89%). Overall satisfaction with the procedure was high (94%). The outcome of surgery with respect to breast size, shape, nipple position, sensation and scarring is documented. All patients expressed marked improvement regarding neck pain, back pain, submammary rash, breast pain and shoulder grooving. Other parameters including psychological wellbeing, quality of life, time on the waiting list, weight of tissue removed and complication rates are analysed. The findings of this study demonstrate overwhelming physical and psychological benefits from surgery. This supports the suggestion that reduction mammaplasty is not primarily cosmetic, producing significant improvement in symptoms.

Stress produced by gavage administration in the rat

This research project examined the relationship between gavage administration of various vehicles and induction of the stress response, as defined by increased plasma corticosterone levels, in the rat. In addition, we assessed elicitation of clinical signs of distress and aspiration leading to airway/pulmonary changes. We studied various vehicles used in toxicology studies, including water, corn oil, and 1% methylcellulose/0.2% Tween 80. Male CD rats received a single gavage administration of vehicle, blood was collected 1 h after dosing for measurement of plasma corticosterone, and necropsies were performed 4 h after dosing. Gavage administration of corn oil at. 20 mL/kg, but not 1% methylcellulose/0.2% Tween 80 or water, induced a stress response in a volume-dependent fashion, resulting in elevated plasma corticosterone levels. This response was not due to aspiration, which occurred after administration of. 20 mL/kg of water or 1% methylcellulose/0.2% Tween 80 but not corn oil. Administration of corn oil at 40 mL/kg resulted in plasma corticosterone levels that were elevated for 4 h. The stress response produced by corn oil was not unique to this vehicle but also occurred after gavage administration of sesame, soybean, and peanut oils. Our data indicate that gavage dosing of lipid vehicles induces activation of the stress response, as indicated by increased adrenal output of corticosterone, in a volume-dependent fashion. In conclusion, gavage administration of various vehicles can result in aspiration, pulmonary injury, and/or elicitation of a stress response in a vehicle- and dose volume-dependent fashion. The results of our project suggest that dose volumes for gavage administration in the rat generally should not exceed 10 mL/kg.

Difluoromethylornithine in combination with tamoxifen in female rats: 13-week oral toxicity study

PURPOSE

Cancer chemoprevention is the use of pharmacologic or natural agents to inhibit the development of cancer. Difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase, the rate-limiting enzyme in the biosynthesis of polyamines. DFMO has demonstrated chemopreventive efficacy in animal models of tumorigenesis. Tamoxifen (TAM) is currently used for treatment of estrogen receptor-positive breast carcinoma and has demonstrated efficacy in chemoprevention of breast cancer in women at high risk for the disease. The administration of tamoxifen with DFMO is being considered for development by the National Cancer Institute as a potential drug regimen for the chemoprevention of breast carcinoma.

METHODS

The toxicity of DFMO in combination with TAM was evaluated in female rats following 13 weeks of daily administration by gavage. Dose groups were vehicle control, DFMO (1000 mg/kg per day), low TAM (0.25 mg/kg per day), high TAM (2.5 mg/kg per day), low combination (1000 + 0.25) and high combination (1000 + 2.5).

RESULTS

No mortalities occurred in the study. Clinical signs of toxicity were limited to dermal lesions consisting of scab formation and abrasions produced by DFMO. Administration of either DFMO or TAM resulted in decreased body weight gains, with coadministration having an additive effect. Serum albumin, total protein, cholesterol and triglyceride levels were decreased in all drug-treated dose groups, although histologic evidence of liver lesions were not seen. TAM resulted in increased numbers of red blood cells, whereas DFMO produced a slightly anemic response. DFMO produced lesions in the small intestine consisting of necrosis of crypt epithelium and crypt microabscess, which were enhanced by TAM coadministration. Administration of TAM resulted in histologic changes in the ovaries, fallopian tube, vagina, cervix and uterus, indicating that inhibition of ovulation and reproductive cycle arrest in the proestrus stage had occurred. Coadministration with DFMO did not affect the changes to the reproductive system induced by TAM.

CONCLUSIONS

Coadministration of DFMO with tamoxifen did not result in toxicity unique to the combination drug regimen, but rather toxicity resulted from administration of each drug. Under the conditions of the study, the overall toxicity produced by dual administration of DFMO with tamoxifen was additive with respect to the toxicity associated with each agent alone.

Bacterial loss from biofilms exposed to free chlorine

Previous studies have demonstrated the increased resistance of biofilm bacteria to biocides when compared with freely suspended planktonic cells, but there have been few investigations of sloughing and losses from biofilms in response to biocide activity. A model biofilm system was used to demonstrate that the loss of sloughed bacteria (including Escherichia coli as a pathogen indicator organism) from actively growing biofilm reached levels of 10(6)-10(7) CFU ml-1 of eluted medium. The sloughing response was examined in response to a range of free chlorine concentrations from 0.6 to 5.0 mg l-1. While chlorine treatment greatly reduced bacterial sloughing, significant bacterial loss into the planktonic phase still occurred with free chlorine concentrations below 3.0 mg l-1, indicating active growth and sloughing of biofilm organisms. Exposure of the biofilm to higher levels of free chlorine resulted in inhibition of bacterial loss, though biocide removal was accompanied by a rapid, almost immediate, recovery of sloughing ability. This work demonstrates the endurance and speed of biofilm recovery upon quenching of chlorine residuals, highlighting a potentially significant public health risk from biofilm recovery and the sloughing of pathogenic organisms associated with the biofilm.

Thirteen-week oral toxicity study of difluoromethylornithine in combination with tamoxifen citrate in female dogs

PURPOSE

Cancer chemoprevention is the use of pharmacologic or natural agents to inhibit the development of cancer. Difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase, the rate-limiting enzyme in the biosynthesis of polyamines. DFMO has demonstrated chemopreventive efficacy in animal models of tumorigenesis. Tamoxifen (TAM), a nonsteroidal antiestrogen, is approved for use in the treatment of estrogen receptor-positive breast carcinoma and has demonstrated efficacy in chemoprevention of breast cancer in women at high risk for the disease. The administration of TAM with DFMO is being considered for development by the National Cancer Institute as a potential drug regimen for the chemoprevention of breast carcinoma.

METHODS

The toxicity of DFMO in combination with TAM was evaluated in female Beagle dogs following 13 weeks of daily oral administration by capsule. Dose levels in milligrams per kilogram body weight per day were: 0 (vehicle control), 100 DFMO, 0.1 TAM, 1.0 TAM, 0.1 TAM + 100 DFMO and 1.0 TAM + 100 DFMO.

RESULTS

No mortalities occurred. Diarrhea was produced by TAM and vaginal discharge, due to reproductive tract lesions, was produced by both DFMO and TAM, either alone or in combination. DFMO decreased reticulocyte counts and TAM increased counts of mature neutrophils. DFMO alone resulted in lesions to the intestines and ovaries, and cornified epithelium of vagina and cervix. TAM produced cornified epithelium of vagina and cervix, and numerous lesions in the ovaries, fallopian tube, uterus, cervix and vagina which were likely due to an estrogen agonist effect. Coadministration of DFMO increased the incidence and/or severity of these reproductive tract lesions. Each compound alone produced ovarian atrophy, and antral follicles and corpora lutea were completely absent in the 1.0 TAM + 100 DFMO group.

CONCLUSIONS

Coadministration of DFMO and TAM resulted in additive toxicity involving the female reproductive system.

Mite allergens: significance of enzymatic activity

Ten years ago, the cloning and sequencing of a cDNA encoding the group I allergen of house-dust mites unequivocally determined that protein allergens may have biochemical functions in addition to their ability to bind IgE. Since this discovery, several groups have speculated that the biochemical activities of allergens, or substances associated with allergens, may be involved in their immunogenicity or allergenicity. This paper will focus on just one biochemical function, proteolytic activity, and will be illustrated by examples of our own work that we believe support the hypothesis that this category of molecules are endowed with the properties of proallergic adjuvants.