Full-field transmission x-ray microscopy for bio-imaging

A full-field hard-x-ray microscope at SSRL has successfully imaged samples of biological and environmental origin at 40 nm resolution. Phase contrast imaging of trabeculae from a female mouse tibia, loaded in vivo to study the effects of weight-bearing on bone structure, revealed a complex network of osteocytes and canaliculi. Imaging of cordgrass roots exposed to mercury revealed nanoparticles with strong absorption contrast. 3D tomography of yeast cells grown in selenium rich media showed internal structure.

Acquisition and eradication of P. aeruginosa in young children with cystic fibrosis

When do infants and young children with cystic fibrosis acquire infection with Pseudomonas aeruginosa? Can this be eradicated when first detected? Children <6 yrs of age participated in an annual bronchoalveolar lavage (BAL)-based microbiological surveillance programme in Perth, Australia. When P. aeruginosa was detected, an eradication programme using combination treatment with i.v., oral and nebulised antibiotics was undertaken. Repeat BAL was performed 3 months following treatment, to assess eradication success. P. aeruginosa was detected in 33 (28.4%) children; median (range) age at detection was 30.5 (3.3-71.4) months. P. aeruginosa was mucoid at detection in six (18.2%) out of 33 patients and associated with respiratory symptoms in 16 (48.5%) out of 33 children. In total, 26 children underwent eradication therapy, with P. aeruginosa eradicated in 20 (77%) out of 26 following one eradication cycle and in three (total 88%) additional children following a second cycle. Eradication was associated with a significant decrease in neutrophil elastase and interleukin-1beta in BAL fluid 12 months post eradication. Eradication of Pseudomonas aeruginosa infection is achievable in young children with cystic fibrosis for up to 5 yrs using combination i.v., oral and nebulised antibiotic therapy and is associated with reduced pulmonary inflammation 12 months post eradication.

A randomized prospective study of extended tocopherol and pentoxifylline therapy, in addition to carbogen, in the treatment of radiation late effects

Purpose:

pentoxifylline (PTX) and tocopherol (vitamin E) are antioxidants previously shown to be useful in combination in the treatment of late radiation induced toxicity. The purpose of this study was to investigate the benefit of combination therapy with carbogen pentoxifylline and tocopherol in the mitigation of late radiation effects. As the optimal duration of PTX and tocopherol treatment has not been fully established, we studied short versus extended treatment duration.

Methods:

we conducted a phase II prospective randomized study of short versus prolonged treatment with pentoxifylline (800 mg) and tocopherol (1000 IU) orally once daily in patients with grade three toxicity post-radical radiotherapy. In addition, all 18 patients received inhaled carbogen (95% O + 5% CO₂) over 90 minutes, five days/week, for three weeks. The primary end point was improved in maximum Lent-Soma toxicity scores.

Results:

maximum Lent-Soma scores improved in six of the 18 patients (response rate 33%). The proportion of patients responding to treatment in the prolonged treatment arm B was more than double than in the shorter arm A, but this did not reach statistical significance (p=0.321). Two patients who had prolonged treatment (arm B) had complete resolution of their symptoms, which was maintained at two and three year follow-ups.

Conclusions:

we recommend prolonged treatment for 12 months, with PTX and tocopherol in combination with carbogen therapy, in the management of late radiation effects.

Hepatitis B reactivation in an Irish dialysis unit, 2005

In April 2005, a case of reactivation of hepatitis B virus (HBV) infection occurred in a patient undergoing haemodialysis in an Irish hospital. This incident potentially affected patients attending hospitals throughout the country, so a national incident team was set up coordinate the response to the incident. A total of 306 dialysis patients, attending 17 different dialysis centres (14 in Ireland), were identified as having been potentially exposed to HBV as a result of this incident. A programme of HBV serological testing and HBV vaccination was instituted. There was no evidence that any patient acquired HBV infection as a result of cross-infection from the index patient, although 11 patients (3.6%) had evidence of past infection (anti-HBc positive, HBsAg negative). The majority of patients in this cohort were of unknown HBV vaccination status (62.7%), 13.4% were fully vaccinated, 4.6% partially vaccinated and 15.7% unvaccinated. Of 239 tested for anti-HBs, 183 (76.6%) had a titre <10 mIU/ml. Local incidents in dialysis units can have national implications due to the frequent patient transfer between units. This incident highlighted serious deficiencies in current structures and practices, and a lack of appropriate guidelines. However, there were positive outcomes from this incident. The majority of Irish dialysis patients have now been vaccinated against HBV, and lessons learned have been used to develop national guidelines on HBV vaccination and testing and on the management of incidents of blood-borne viral infections in dialysis units.

Hepatitis A antibody prevalence among people with an intellectual disability in Ireland

This manuscript aims to determine the prevalence of antibody to and risk factors for hepatitis A virus (HAV) in individuals attending three intellectual disability services through a cross-sectional survey held in Dublin, Ireland. Participants were 636 individuals aged four to 78 years attending three intellectual disability services. The main outcome measure was the measurement of anti-HAV (IgG antibody) in oral fluid swabs using an antibody capture enzyme immunoassay (EIA) technique. Risk factor information was obtained by questionnaire from the individual’s medical record.

Platelet beta-secretase activity is increased in Alzheimer's disease

beta-Secretase activity is the rate-limiting step in Abeta peptide production from amyloid precursor protein. Abeta is a major component of Alzheimer's disease (AD) cortical amyloid plaques. beta-Secretase activity is elevated in post mortem brain tissue in AD. The current study investigated whether beta-secretase activity was also elevated in peripheral blood platelets. We developed a novel fluorimetric beta-secretase activity assay to investigate platelets isolated from individuals with AD (n=86), and age-matched controls (n=115). Platelet membrane beta-secretase activity (expressed as initial rate) varied over fourfold between individuals, raising important questions about in vivo regulation of this proteolytic activity. Nonetheless, we identified a significant 17% increase in platelet membrane beta-secretase activity in individuals with AD compared to controls (p=0.0003, unpaired t-test). Platelet membrane beta-secretase activity did not correlate with mini-mental state examination (MMSE) score in the AD group (mean MMSE=17.7, range 1-23), indicating that the increase did not occur as a secondary result of the disease process, and may even have preceded symptom onset.

Whole body MR imaging: Applications in oncology

This article reviews technique and clinical applications of whole body MR imaging as a diagnostic tool in cancer staging. In particular the article reviews its role as an alternative to scintigraphy (bone scan and PET) in staging skeletal spread of disease, its role in assessing total tumour burden, its role in multiple myeloma and finally its evolving non oncologic role predominantly assessing total body composition.

Inducible NO synthase expression is low in airway epithelium from young children with cystic fibrosis

BACKGROUND

This is the first study to measure inducible nitric oxide synthase (iNOS) gene and protein expression quantitatively in primary epithelial cells from very young children with cystic fibrosis (CF). Low levels of exhaled nitric oxide (NO) in CF suggest dysregulation of NO production in the airway. Due to the importance of NO in cell homeostasis and innate immunity, any defect in the pathway associated with CF would be a potential target for treatment.

METHODS

Cells were obtained by tracheobronchial brushing from 40 children with CF of mean (SD) age 2.1 (1.5) years and from 12 healthy non-atopic children aged 3.4 (1.2) years. Expression of iNOS mRNA was measured using quantitative PCR and iNOS protein by immunofluorescence and Western blot analysis.

RESULTS

Inducible NOS mRNA expression was significantly lower in CF patients with and without bacterial infection than in healthy children (0.22 and 0.23 v 0.76; p=0.002 and p=0.01, respectively). Low levels of iNOS gene expression were accompanied by low levels of iNOS protein expression as detected by Western blot analysis.

CONCLUSIONS

These results support the findings of previous studies in adult patients with advanced disease, cell lines, and animal models. Our findings reflect the situation in children with mild lung disease. They indicate that low iNOS expression may be an innate defect in CF with potential consequences for local antimicrobial defence and epithelial cell function and provide evidence for an approach to treatment based on increasing epithelial NO production or the sensitivity of NO dependent cellular processes.

Exhaled nitric oxide is not reduced in infants with cystic fibrosis

Fractional exhaled nitric oxide (F(eNO)) has been reported to be reduced in cystic fibrosis (CF) patients. However, data from young children are conflicting and it is not clear whether this is a primary feature of the disease or a secondary response. The present study compared F(eNO) between CF and healthy infants using a validated single-breath technique. A total of 23 healthy infants (11 females; mean age 40.1 weeks) and 18 infants with CF (nine females; 64.9 weeks) underwent tests of lung function and F(eNO). Bronchoalveolar lavage (BAL) was collected from all CF infants 2-5 days after lung function testing. There was no significant difference in F(eNO) between the CF and healthy infants (geometric mean: 23.1 parts per billion (ppb) and 17.0 ppb, respectively). There was an inverse relationship between age and F(eNO) in the CF patients, but not in the healthy group. Within the CF group, there was no association between F(eNO) and any marker of airway inflammation measured in the BAL. Exhaled nitric oxide is not reduced in cystic fibrosis infants, but does decrease with age. The current data indicate that F(eNO) is not a good marker of airway inflammation in cystic fibrosis.

Nasal wash as an alternative to bronchoalveolar lavage in detecting early pulmonary inflammation in children with cystic fibrosis

OBJECTIVE

The aim of this study was to determine whether nasal inflammation reflects pulmonary inflammation in young children with cystic fibrosis (CF), as assessed by inflammatory markers in nasal wash (NW) and bronchoalveolar lavage (BAL), respectively.

METHODS

CF patients younger than 6 years of age who were to undergo bronchoscopy for routine BAL from May 2000 to October 2001 were recruited for this study. NW was collected immediately after the patient was sedated for bronchoscopy. Total cell counts (TCC), differential cell counts and interleukin (IL)-8 levels (enzyme-linked immunosorbent assay) were assessed in NW and BAL.

RESULTS

In total, 19 children with CF (mean age, 1.9 years; SD, 1.7 years) were included in the study. There was a significant relationship between IL-8 and the percentages of neutrophils in NW (r (2) = 0.76; P < 0.001) and in BAL fluid (r 2 = 0.62; P = 0.006). Similarly, IL-8 concentrations in the NW correlated with those in the BAL (r 2 = 0.48; P = 0.036) and neutrophil percentages in NW correlated significantly with those in BAL (r 2 = 0.7; P = 0.004).

CONCLUSION

When measured under 'ideal' conditions, nasal IL-8 reflects lower airway levels and may reflect the inflammatory stimulus that results in neutrophilic inflammation. These data encourage further assessment of nasal wash under clinically appropriate conditions to determine its utility for assessing inflammation in young children with CF.

Altruistic living donors: evaluation for nondirected kidney or liver donation

A program was established within our regional procurement organization to permit evaluation of altruistic living donors (LD) interested in nondirected kidney or liver segment donation prior to transplant center referral. During the initial 30 months of program operations, 731 donor inquiries were received of which 131 individuals called back after review of mailed information materials. Forty-seven candidates initiated and 19 completed the evaluation process. Seven underwent donation to include six kidneys and one liver segment, five are actively pending donation, five were excluded from donation following transplant center evaluation and two took no further action after their intended liver recipients received deceased donor (DD) transplants. Psychological evaluation of these 19 candidates found them to be free of psychopathology, highly cooperative and self-directed. They did not exhibit attention-seeking or religious motivations for their actions. All seven donors and recipients continue to do well postoperatively. This evaluation program has made possible large-scale screening and education of prospective altruistic LD within the general population and also provides a unique opportunity to further our understanding of those individuals interested in living-nondirected donation.

Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb

The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotropy indicates that the initially generated fluid differs significantly from the equilibrium liquid.

CD14 C-159T and early infection with Pseudomonas aeruginosa in children with cystic fibrosis

Early acquisition of Pseudomonas aeruginosa is associated with a poorer prognosis in patients with cystic fibrosis. We investigated whether polymorphisms in CD14, the lipopolysaccharide receptor, increase the risk of early infection. Forty-five children with cystic fibrosis were investigated with annual bronchoalveolar lavage (BAL) and plasma sCD14 levels. Plasma sCD14 levels were significantly lower in children from whom P.aeruginosa was subsequently isolated (492.75 microg/ml vs. 1339.43 microg/ml, p = 0.018). Those with the CD14 -159CC genotype had a significantly increased risk of early infection with P.aeruginosa suggesting that CD14 C-159T plays a role in determining the risk of early infection with P.aeruginosa.

Atomic-Scale Visualization of Inertial Dynamics

The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.