Patient characteristics in tardive COVID-19 pseudoperniosis: a case series of 16 patients.

BACKGROUND: Acute pseudoperniosis (PP) has a recognized association with COVID-19 and tends to occur without cold precipitation in young, healthy patients, often without a clear history of COVID-19. These lesions usually resolve within 2 weeks and without long-term sequelae. In the early months of 2021, patients with delayed and protracted PP began to emerge. We have called this presentation 'tardive COVID-19 PP (TCPP)'. AIM: To consolidate and expand knowledge on TCPP, we describe the clinical characteristics, treatments and outcomes of 16 patients with TCPP who were reviewed by our outpatient dermatology service. RESULTS: The initial clinical manifestations were erythema, swelling and PP of the fingers in 56.2%, and of the toes in 31.2%, desquamation in 56.2% and acrocyanosis in 12.5%. Ten patients had eventual involvement of all acral sites. The median duration of symptoms was 191 days. Six patients reported close contact with a confirmed or suspected case of COVID-19, but only two had positive COVID-19 tests. Four patients experienced complete or almost complete resolution of symptoms, while the rest remain under active treatment. CONCLUSION: Unlike acute PP, TCPP has a protracted and delayed presentation that is typically associated with profound acrocyanosis. Patients with TCPP represent a new phenomenon that is part of the post-COVID-19 syndrome, with risk factors and pathophysiology that are not yet fully understood. Our data indicate that likely predisposing factors for developing TCPP include young age, a preceding history of cold intolerance and an arachnodactyloid phenotype. Anorexia, connective tissue disorders or sickle cell trait may also predispose to TCPP. In addition, low titre antinuclear antibody positivity, the presence of cryoglobulins, or low complement levels may represent further risk factors. Finally, prolonged low temperatures are also likely to be contributing to the symptoms.

Anti-EGFR-resistant clones decay exponentially after progression: implications for anti-EGFR re-challenge.

BACKGROUND: Colorectal cancer (CRC) has been shown to acquire RAS and EGFR ectodomain mutations as mechanisms of resistance to epidermal growth factor receptor (EGFR) inhibition (anti-EGFR). After anti-EGFR withdrawal, RAS and EGFR mutant clones lack a growth advantage relative to other clones and decay; however, the kinetics of decay remain unclear. We sought to determine the kinetics of acquired RAS/EGFR mutations after discontinuation of anti-EGFR therapy. PATIENTS AND METHODS: We present the post-progression circulating tumor DNA (ctDNA) profiles of 135 patients with RAS/BRAF wild-type metastatic CRC treated with anti-EGFR who acquired RAS and/or EGFR mutations during therapy. Our validation cohort consisted of an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling. A separate retrospective cohort of 80 patients was used to evaluate overall response rate and progression free survival during re-challenge therapies. RESULTS: Our analysis showed that RAS and EGFR relative mutant allele frequency decays exponentially (r2=0.93 for RAS; r2=0.94 for EGFR) with a cumulative half-life of 4.4 months. We validated our findings using an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling, confirming exponential decay with an estimated half-life of 4.3 months. A separate retrospective cohort of 80 patients showed that patients had a higher overall response rate during re-challenge therapies after increasing time intervals, as predicted by our model. CONCLUSION: These results provide scientific support for anti-EGFR re-challenge and guide the optimal timing of re-challenge initiation.

Multiplex KRASG12/G13 mutation testing of unamplified cell-free DNA from the plasma of patients with advanced cancers using droplet digital polymerase chain reaction.

Background: Cell-free DNA (cfDNA) from plasma offers easily obtainable material for KRAS mutation analysis. Novel, multiplex, and accurate diagnostic systems using small amounts of DNA are needed to further the use of plasma cfDNA testing in personalized therapy. Patients and methods: Samples of 16 ng of unamplified plasma cfDNA from 121 patients with diverse progressing advanced cancers were tested with a KRASG12/G13 multiplex assay to detect the seven most common mutations in the hotspot of exon 2 using droplet digital polymerase chain reaction (ddPCR). The results were retrospectively compared to mutation analysis of archival primary or metastatic tumor tissue obtained at different points of clinical care. Results: Eighty-eight patients (73%) had KRASG12/G13 mutations in archival tumor specimens collected on average 18.5 months before plasma analysis, and 78 patients (64%) had KRASG12/G13 mutations in plasma cfDNA samples. The two methods had initial overall agreement in 103 (85%) patients (kappa, 0.66; ddPCR sensitivity, 84%; ddPCR specificity, 88%). Of the 18 discordant cases, 12 (67%) were resolved by increasing the amount of cfDNA, using mutation-specific probes, or re-testing the tumor tissue, yielding overall agreement in 115 patients (95%; kappa 0.87; ddPCR sensitivity, 96%; ddPCR specificity, 94%). The presence of ≥ 6.2% of KRASG12/G13 cfDNA in the wild-type background was associated with shorter survival (P = 0.001). Conclusion(s): Multiplex detection of KRASG12/G13 mutations in a small amount of unamplified plasma cfDNA using ddPCR has good sensitivity and specificity and good concordance with conventional clinical mutation testing of archival specimens. A higher percentage of mutant KRASG12/G13 in cfDNA corresponded with shorter survival.

A multifaceted hospital-wide intervention increases hand hygiene compliance.

BACKGROUND: Hand hygiene is an important and basic practice that should be used by all healthcare staff to protect both themselves and their patients against infection. Unfortunately hand hygiene compliance remains poor. OBJECTIVE: To show an improvement in hand hygiene compliance using a multifaceted approach. METHODS: This was a quasiexperimental pre-post intervention study design with a number of standardised interventions to promote hand hygiene. The World Health Organization hand hygiene multimodal (five-step) intervention approach was used. The study ran from June 2015 to August 2015 in 11 selected wards of a 975-bed tertiary and quaternary care public hospital (Groote Schuur Hospital, Cape Town, South Africa). The outcome was to assess improvement in hand hygiene compliance monthly over the 3 months, compared with non-intervention wards and compared with the wards' own performance measured in 2014. The study included both descriptive and analytical components. RESULTS: Post intervention, hand hygiene compliance showed a statistically significant improvement for before patient contact from 34% in 2014 to 76% in 2015 (p<0.05) and for after patient contact from 47% in 2014 to 82% in 2015 (p<0.05). CONCLUSION: The intervention improved hand hygiene compliance and can easily be replicated in other wards, resulting in sustaining a culture of hand hygiene improvement and behavioural change throughout the hospital.

Utility of a molecular prescreening program in advanced colorectal cancer for enrollment on biomarker-selected clinical trials.

BACKGROUND: Incorporation of multiple enrichment biomarkers into prospective clinical trials is an active area of investigation, but the factors that determine clinical trial enrollment following a molecular prescreening program have not been assessed. PATIENTS AND METHODS: Patients with 5-fluorouracil-refractory metastatic colorectal cancer at the MD Anderson Cancer Center were offered screening in the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) program to identify eligibility for companion phase I or II clinical trials with a therapy targeted to an aberration detected in the patient, based on testing by immunohistochemistry, targeted gene sequencing panels, and CpG island methylation phenotype assays. RESULTS: Between August 2010 and December 2013, 484 patients were enrolled, 458 (95%) had a biomarker result, and 157 (32%) were enrolled on a clinical trial (92 on biomarker-selected and 65 on nonbiomarker selected). Of the 458 patients with a biomarker result, enrollment on biomarker-selected clinical trials was ninefold higher for predefined ATTACC-companion clinical trials as opposed to nonpredefined biomarker-selected clinical trials, 17.9% versus 2%, P < 0.001. Factors that correlated positively with trial enrollment in multivariate analysis were higher performance status, older age, lack of standard of care therapy, established patient at MD Anderson, and the presence of an eligible biomarker for an ATTACC-companion study. Early molecular screening did result in a higher rate of patients with remaining standard of care therapy enrolling on ATTACC-companion clinical trials, 45.1%, in contrast to nonpredefined clinical trials, 22.7%; odds ratio 3.1, P = 0.002. CONCLUSIONS: Though early molecular prescreening for predefined clinical trials resulted in an increase rate of trial enrollment of nonrefractory patients, the majority of patients enrolled on clinical trials were refractory to standard of care therapy. Within molecular prescreening programs, tailoring screening for preidentified and open clinical trials, temporally linking screening to treatment and optimizing both patient and physician engagement are efforts likely to improve enrollment on biomarker-selected clinical trials. CLINICAL TRIALS NUMBER: The study NCT number is NCT01196130.

A longitudinal observational study of Salmonella shedding patterns by commercial turkeys during rearing and fattening, showing limitations of some control measures.

1. The onset and progression of Salmonella infections was investigated in commercial turkey flocks from placement at 1 d old until slaughter in "brood and move" systems using a longitudinal observational approach based on faeces and environmental sampling with subsequent culture of Salmonella. 2. Persistent Salmonella Newport contamination was found within rearing houses and on their external concrete aprons after cleaning and disinfection between crops of heavily shedding young birds. 3. Salmonella shedding was often detected by 5 d of age and the frequency of positive samples peaked at 14-35 d. Thereafter Salmonella isolations declined, especially in the later (fattening) stages. Samples were still Salmonella-positive at low prevalence in half of the intensively sampled houses at slaughter age. 4. A number of management interventions to combat Salmonella infection of flocks, including sourcing policy, competitive exclusion cultures and cleaning and disinfection, were inadequate to prevent flock infection, although improved disinfection on one unit was associated with a delay in the onset of flock infection.

Characterizing the patterns of clonal selection in circulating tumor DNA from patients with colorectal cancer refractory to anti-EGFR treatment.

INTRODUCTION: KRAS and EGFR ectodomain-acquired mutations in patients with metastatic colorectal cancer (mCRC) have been correlated with acquired resistance to anti-EGFR monoclonal antibodies (mAbs). We investigated the frequency, co-occurrence, and distribution of acquired KRAS and EGFR mutations in patients with mCRC refractory to anti-EGFR mAbs using circulating tumor DNA (ctDNA). PATIENTS AND METHODS: Sixty-two post-treatment plasma and 20 matching pretreatment archival tissue samples from KRAS (wt) mCRC patients refractory to anti-EGFR mAbs were evaluated by high-sensitivity emulsion polymerase chain reaction for KRAS codon 12, 13, 61, and 146 and EGFR 492 mutations. RESULTS: Plasma analyses showed newly detectable EGFR and KRAS mutations in 5/62 [8%; 95% confidence interval (CI) 0.02-0.18] and 27/62 (44%; 95% CI 0.3-0.56) samples, respectively. KRAS codon 61 and 146 mutations were predominant (33% and 11%, respectively), and multiple EGFR and/or KRAS mutations were detected in 11/27 (41%) cases. The percentage of mutant allele reads was inversely correlated with time since last treatment with EGFR mAbs (P = 0.038). In the matching archival tissue, these mutations were detectable as low-allele-frequency clones in 35% of patients with plasma mutations after treatment with anti-EGFR mAbs and correlated with shorter progression-free survival (PFS) compared with the cases with no new mutations (3.0 versus 8.0 months, P = 0.0004). CONCLUSION: Newly detected KRAS and/or EGFR mutations in plasma ctDNA from patients refractory to anti-EGFR treatment appear to derive from rare, pre-existing clones in the primary tumors. These rare clones were associated with shorter PFS in patients receiving anti-EGFR treatment. Multiple simultaneous mutations in KRAS and EGFR in the ctDNA and the decline in allele frequency after discontinuation of anti-EGFR therapy in a subset of patients suggest that several resistance mechanisms can co-exist and that relative clonal burdens may change over time. Monitoring treatment-induced genetic alterations by sequencing ctDNA could identify biomarkers for treatment screening in anti-EGFR-refractory patients.

Association between KRAS mutation and lung metastasis in advanced colorectal cancer.

BACKGROUND: KRAS mutations have been associated with lung metastases at diagnosis of metastatic colorectal cancer (mCRC), but the impact of this mutation on subsequent development of lung metastasis is unknown. We investigated KRAS mutation as a predictor of lung metastasis development. METHODS: We retrospectively evaluated data from patients with mCRC whose tumour was tested for KRAS mutation from 2008 to 2010. The relationships of KRAS mutational status with time-to-lung metastasis (TTLM) and overall survival (OS) were analysed. RESULTS: Of the 494 patients identified, 202 (41%) had tumours with KRAS mutation. KRAS mutations were associated with a shorter TTLM (median 15.2 vs 22.4 months; hazard ratio=1.40; P=0.002) and a two-fold greater odds of developing lung metastases during the disease course in patients with liver-limited mCRC at diagnosis (72 vs 56%, P=0.007). Overall survival did not differ by KRAS status. CONCLUSIONS: Lung metastasis was more likely to develop during the disease course in patients whose tumour had a KRAS mutation than in those whose tumour did not have a KRAS mutation. This finding may have an impact on decision making for surgical resection of metastatic disease.

Clinicopathologic characteristics and gene expression analyses of non-KRAS 12/13, RAS-mutated metastatic colorectal cancer.

BACKGROUND: KRAS mutations in codons 12 and 13 are present in ∼40% of all colorectal cancers (CRC). Activating mutations in codons 61 and 146 of KRAS and in codons 12, 13, and 61 of NRAS also occur but are less frequent. The clinicopathologic features and gene expression profiles of this latter subpopulation of RAS-mutant colorectal tumors have not yet been clearly defined but in general are treated similarly to those with KRAS 12 or 13 mutations. PATIENTS AND METHODS: Records of patients with metastatic CRC (mCRC) treated at MD Anderson Cancer Center between December 2000 and August 2012 were reviewed for RAS (KRAS or NRAS) and BRAF mutation status, clinical characteristics, and survival outcomes. To study further with an independent cohort, data from The Cancer Genome Atlas were analyzed to define a gene expression signature for patients whose tumors feature these atypical RAS mutations and explore differences with KRAS 12/13-mutated colorectal tumors. RESULTS: Among the 484 patients reviewed, KRAS 12/13, KRAS 61/146, NRAS, and BRAF mutations were detected in 47.7%, 3.0%, 4.1%, and 7.4%, respectively, of patients who were tested for each of these aberrations. Lung metastases were more common in both the KRAS 12/13-mutated and atypical RAS-mutated cohorts relative to patients with RAS/BRAF wild-type tumors. Gene expression analyses revealed similar patterns regardless of the site of RAS mutation, and in silico functional algorithms predicted that KRAS and NRAS mutations in codons 12, 13, 61, and 146 alter the protein function and drive tumorgenesis. CONCLUSIONS: Clinicopathologic characteristics, survival outcomes, functional impact, and gene expression profiling were similar between patients with KRAS 12/13 and those with NRAS or KRAS 61/146-mutated mCRC. These clinical and bioinformatic findings support the notion that colorectal tumors driven by these RAS mutations are phenotypically similar.

[Evolution of lower urinary tract symptoms under silodosin: factors influencing patients' satisfaction]. / Évolution des symptômes du bas appareil urinaire sous silodosine: facteurs influençant la satisfaction des patients.

UNLABELLED: The objective of this study was to analyze the efficacy and safety of silodosin in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) in current urologic practice. METHOD: This was a prospective observational study conducted by 272 urologists on patients treated by silodosin for BPH. The parameters evaluated were the weighted IPSS score, the IPSS question 8 related to quality of life, the USP score and the Athens Insomnia Scale (AIS) measured at treatment initiation and after 3 months. RESULTS: Nine hundred and fourteen patients whose average age was 66 years with LUTS for 3.3 years were analyzed. After 3 months of treatment, a significant decrease in IPSS (from 16.2 ± 6.1 to 9.7 ± 5.5, P<0.0001) and USP score (from 10.6 ± 5.1 to 6 0 ± 4.6, P<0.0001) were observed, quality of life (from 67.1% to 14.4% of unsatisfied patients, P<0.0001) and sleep were significantly improved (from 49.2% to 28.9% patients with insomnia, P<0.0001). Among the patients, 21.2% experienced at least one adverse event. The most frequent were abnormal ejaculation (17.2%). And 7.1% discontinued the treatment for this reason. After 3 months of treatment silodosin was continued in 86.9% of patients. CONCLUSION: This large study confirmed the efficacy of silodosin in LUTS associated with BPH with a safety profile that does not affect patient satisfaction.

Nanoparticle-mediated catalase delivery protects human neurons from oxidative stress.

Several neurodegenerative diseases and brain injury involve reactive oxygen species and implicate oxidative stress in disease mechanisms. Hydrogen peroxide (H2O2) formation due to mitochondrial superoxide leakage perpetuates oxidative stress in neuronal injury. Catalase, an H2O2-degrading enzyme, thus remains an important antioxidant therapy target. However, catalase therapy is restricted by its labile nature and inadequate delivery. Here, a nanotechnology approach was evaluated using catalase-loaded, poly(lactic co-glycolic acid) nanoparticles (NPs) in human neuronal protection against oxidative damage. This study showed highly efficient catalase encapsulation capable of retaining ~99% enzymatic activity. NPs released catalase rapidly, and antioxidant activity was sustained for over a month. NP uptake in human neurons was rapid and nontoxic. Although human neurons were highly sensitive to H2O2, NP-mediated catalase delivery successfully protected cultured neurons from H2O2-induced oxidative stress. Catalase-loaded NPs significantly reduced H2O2-induced protein oxidation, DNA damage, mitochondrial membrane transition pore opening and loss of cell membrane integrity and restored neuronal morphology, neurite network and microtubule-associated protein-2 levels. Further, catalase-loaded NPs improved neuronal recovery from H2O2 pre-exposure better than free catalase, suggesting possible applications in ameliorating stroke-relevant oxidative stress. Brain targeting of catalase-loaded NPs may find wide therapeutic applications for oxidative stress-associated acute and chronic neurodegenerative disorders.

Freezing as an intervention to reduce the numbers of campylobacters isolated from chicken livers.

The aims of this study were (i) to determine the prevalence and numbers of campylobacters in 63 samples of raw livers purchased at retail across the UK and (ii) to investigate whether the freezing of chicken livers contaminated with Campylobacter was a reliable method for decontamination. Chicken livers naturally contaminated with campylobacters were subjected to freezing at -15 and -25°C for one day and 7 days. Numbers of campylobacters on the livers were determined immediately before and after a 24-h or 7-days freeze treatment and daily during 3 days post-thaw refrigerated storage. Freezing for 24 h at -25°C can reduce numbers of Campylobacter by up to 2 log10 CFU g(-1). Freezing the livers for 24 h at -25°C, thawing overnight in a fridge set to 4°C and refreezing for another 24 h at -25°C reduced the numbers of campylobacters by up to three logs. Reduction in the numbers of campylobacters was significantly greater following a second freeze treatment compared with a single freeze treatment.

Galectin 3-ß-galactobiose interactions.

Force spectroscopy has been used to investigate the interaction between the disaccharide ß-galactobiose and the pro-metastatic regulatory protein galectin-3 (Gal3). The studies revealed specific interactions characterised by an off-rate dissociation constant k(off)=0.33 s(-1) and interaction distance x=0.2 nm at zero applied force. These data suggest a lifetime for the interaction of 3.0 s. The results are consistent with the hypothesis that oral consumption of modified citrus pectin controls cancer metastasis by inhibiting the role of Gal3. The modification is considered to facilitate binding of pectin-derived galactan sidechains to Gal3 and inhibition of the roles of Gal3 as a pro-metastatic regulatory protein.

Persistent environmental reservoirs on farms as risk factors for Campylobacter in commercial poultry.

Campylobacter is the most common known source of human bacterial enteritis in the developed world and poultry is considered the main source. Broilers often become colonized with Campylobacter during rearing, and then contaminate the farm environment. The objective of this study was to identify Campylobacter-positive environmental reservoirs on farms, as these pose a risk to broiler flocks becoming colonized with Campylobacter. We considered the temporal aspects of exposure and colonization. A longitudinal study monitored six conventional rearing farms over 2 years. The broiler flocks, catchers' equipment, vehicles, shed surrounds, shed entrance, other equipment, farm entrance, other animals, puddles, dead birds, mains water and drinkers were systematically sampled 2-4 times per flock. A multivariable generalized estimating equation model was used to assess associations between contaminated environmental sites and colonized broiler flocks. The associations were adjusted for confounders and other known risk factors. To further assess temporality of contamination, the sequence of contamination of the different environmental sites and the flocks was established. Contaminated shed entrances and anterooms, contaminated drinkers and shedding of Campylobacter by other animals such as cattle, dogs, wildlife and rodents were significantly associated with positive flocks. The reservoir of 'other animals' was also the reservoir most commonly positive before the flock became colonized. The other sites usually became contaminated after the flock was colonized.

Investigating the effect of an arterial hypertension drug on the structural properties of plasma protein.

Propanolol is a betablocker drug used in the treatment of arterial hypertension related diseases. In order to achieve an optimal performance of this drug it is important to consider the possible interactions of propanolol with plasma proteins. In this work, we have used several experimental techniques to characterise the effect of addition of the betablocker propanolol on the properties of bovine plasma fibrinogen (FB). Differential scanning calorimeter (DSC), circular dichroism (CD), dynamic light scattering (DLS), surface tension techniques and atomic force microscopy (AFM) measurements have been combined to carry out a detailed physicochemical and surface characterization of the mixed system. As a result, DSC measurements show that propranolol can play two opposite roles, either acting as a structure stabilizer at low molar concentrations or as a structure destabilizer at higher concentrations, in different domains of fibrinogen. CD measurements have revealed that the effect of propanolol on the secondary structure of fibrinogen depends on the temperature and the drug concentration and the DLS analysis showed evidence for protein aggregation. Interestingly, surface tension measurements provided further evidence of the conformational change induced by propanolol on the secondary structure of FB by importantly increasing the surface tension of the system. Finally, AFM imaging of the fibrinogen system provided direct visualization of the protein structure in the presence of propanolol. Combination of these techniques has produced complementary information on the behavior of the mixed system, providing new insights into the structural properties of proteins with potential medical interest.

Emerging roles of engineered nanomaterials in the food industry.

Nanoscience is the study of phenomena and the manipulation of materials at the atomic or molecular level. Nanotechnology involves the design, production and use of structures through control of the size and shape of the materials at the nanometre scale. Nanotechnology in the food sector is an emerging area with considerable research and potential products. There is particular interest in the definition and regulation of engineered nanomaterials. This term covers three classes of nanomaterials: natural and processed nanostructures in foods; particulate nanomaterials metabolized or excreted on digestion; and particulate nanomaterials not broken down on digestion, which accumulate in the body. This review describes examples of these classes and their likely status in the food industry.

Potential sources of Campylobacter infection on chicken farms: contamination and control of broiler-harvesting equipment, vehicles and personnel.

AIMS: To test the efficacy of enhanced biosecurity measures on poultry farms for reducing environmental contamination with Campylobacter during partial depopulation of broiler flocks prior to normal slaughter age. The study has also evaluated the risk of infection from live-bird transport crates that are routinely cleaned at the slaughterhouse, but may remain contaminated. METHODS AND RESULTS: On-farm sampling and Campylobacter isolation was undertaken to compare the prevalence of contamination on vehicles, equipment and catching personnel during farm visits that took place under normal or enhanced biosecurity. Campylobacters were found in almost all types of sample examined and enhanced biosecurity reduced the prevalence. However, the additional measures failed to prevent colonisation of the flocks. For transport crates, challenge trials involved exposure of broilers to commercially cleaned crates and genotyping of any campylobacters isolated. The birds were rapidly colonised with the same genotypes as those isolated from the cleaned crates. CONCLUSIONS: The enhanced biosecurity measures were insufficient to prevent flock colonisation, and the problem was exacerbated by inadequate cleaning of transport crates at the slaughterhouse. SIGNIFICANCE AND IMPACT OF THE STUDY: Current commercial practices in the United Kingdom facilitate the spread of campylobacters among broiler chicken flocks. Prevention of flock infection appears to require more stringent biosecurity than that studied here.

Effect of delivery method on the efficacy of Salmonella vaccination in chickens.

To investigate whether the efficacy of live vaccines is influenced by the mode of vaccine delivery, a widely-used UK live commercial Salmonella Enteritidis vaccine was delivered to pullet chicks either by spray, in drinking water, or in combination with a bivalent vaccine containing inactivated Salmonella Enteritidis and Salmonella Typhimurium. The birds were subsequently challenged with 10(2) or 10(8) colony-forming units (cfu) of Salmonella Enteritidis through drinking water at either six or 20 weeks of age. Ten days after the challenge, the birds were euthanased and their caecal contents cultured for Salmonella. All of the vaccinated groups contained fewer Salmonella Enteritidis-positive birds than the unvaccinated groups. The 'spray-vaccinated' group contained significantly fewer Salmonella Enteritidis-positive birds than the 'water-vaccinated' group after challenge with 10(8) cfu at 20 weeks. However, there was little or no difference at the other challenge time points between the groups that received vaccine through different modes of delivery.

The nano-morphological relationships between apatite crystals and collagen fibrils in ivory dentine.

In this work, analytical transmission electron microscopy (TEM) was used to study the nanostructure of mineralised ivory dentine, in order to gain a clearer understanding of the relationship between the organic (collagen fibrils) and inorganic (calcium phosphate apatite crystals) components. Thin sections prepared by both focused ion beam (FIB) milling and ultramicrotomy, in the longitudinal and transverse planes, were investigated using electron energy-loss spectroscopy (EELS) in a monochromated field-emission gun scanning TEM (FEI Titan 80-300 FEGSTEM). Both low- and core-loss spectroscopy were used in the investigation, and the signals from phosphorous, carbon, calcium, nitrogen and oxygen were studied in detail. A combination of HAADF (high-angle annular dark-field)-STEM imaging and EELS analysis was used for simultaneous acquisition of both spatial and spectral information pixel by pixel (spectrum imaging). Across the collagen D banding in longitudinal sections, the relative thickness of the bright bands was significantly higher than that of the dark bands. Core-loss spectroscopy showed that the bright bands were richer in apatite than the dark bands. However, no ELNES variation was observed across the D banding. In transverse sections, significant changes in the carbon edge fine structure were observed at the interface between the extra- and intra-fibrillar regions.