Characterization of buried interfaces using Ga Kα hard X-ray photoelectron spectroscopy (HAXPES)

HAXPES enables the detection of buried interfaces with an increased photo electron sampling depth.

Water-induced reordering in ultrathin ionic liquid films

Water-induced reordering in ultrathin ionic liquid films has been observed using in situ x-ray photoelectron spectroscopy. An ultrathin layer of 1-butyl-3-methylimidazolium tetrafluoroborate ([C₄C₁Im][BF₄]) was deposited on a rutile TiO₂ (1 1 0) single crystal and exposed to water vapour at a relative humidity of ~70% in an in situ cell. Water was found to adsorb onto the ionic liquid surface, causing a reordering of the ions at the interface. Water initially remained trapped on the ionic liquid surface as the in situ cell was evacuated. This could have negative implications for supported ionic liquid phase catalysis, where reactants and products move in and out of an ionic liquid containing the catalyst. This insight into the behaviour at the water/ionic liquid interface provides a basis for understanding interfacial behaviour in more complex gas/ionic liquid systems.

The National Landscape of Living Kidney Donor Follow-Up in the United States

In 2013, the Organ Procurement and Transplantation Network (OPTN)/ United Network for Organ Sharing (UNOS) mandated that transplant centers collect data on living kidney donors (LKDs) at 6 months, 1 year, and 2 years postdonation, with policy-defined thresholds for the proportion of complete living donor follow-up (LDF) data submitted in a timely manner (60 days before or after the expected visit date). While mandated, it was unclear how centers across the country would perform in meeting thresholds, given potential donor and center-level challenges of LDF. To better understand the impact of this policy, we studied Scientific Registry of Transplant Recipients data for 31,615 LKDs between January 2010 and June 2015, comparing proportions of complete and timely LDF form submissions before and after policy implementation. We also used multilevel logistic regression to assess donor- and center-level characteristics associated with complete and timely LDF submissions. Complete and timely 2-year LDF increased from 33% prepolicy (January 2010 through January 2013) to 54% postpolicy (February 2013 through June 2015) (p < 0.001). In an adjusted model, the odds of 2-year LDF increased by 22% per year prepolicy (p < 0.001) and 23% per year postpolicy (p < 0.001). Despite these annual increases in LDF, only 43% (87/202) of centers met the OPTN/UNOS-required 6-month, 1-year, and 2-year LDF thresholds for LKDs who donated in 2013. These findings motivate further evaluation of LDF barriers and the optimal approaches to capturing outcomes after living donation.

Detection of Focal Longitudinal Changes in the Brain by Subtraction of MR Images

BACKGROUND AND PURPOSE

The detection of new subtle brain pathology on MR imaging is a time-consuming and error-prone task for the radiologist. This article introduces and evaluates an image-registration and subtraction method for highlighting small changes in the brain with a view to minimizing the risk of missed pathology and reducing fatigue.

MATERIALS AND METHODS

We present a fully automated algorithm for highlighting subtle changes between multiple serially acquired brain MR images with a novel approach to registration and MR imaging bias field correction. The method was evaluated for the detection of new lesions in 77 patients undergoing cardiac surgery, by using pairs of fluid-attenuated inversion recovery MR images acquired 1-2 weeks before the operation and 6-8 weeks postoperatively. Three radiologists reviewed the images.

RESULTS

On the basis of qualitative comparison of pre- and postsurgery FLAIR images, radiologists identified 37 new ischemic lesions in 22 patients. When these images were accompanied by a subtraction image, 46 new ischemic lesions were identified in 26 patients. After we accounted for interpatient and interradiologist variability using a multilevel statistical model, the likelihood of detecting a lesion was 2.59 (95% CI, 1.18-5.67) times greater when aided by the subtraction algorithm (P = .017). Radiologists also reviewed the images significantly faster (P < .001) by using the subtraction image (mean, 42 seconds; 95% CI, 29-60 seconds) than through qualitative assessment alone (mean, 66 seconds; 95% CI, 46-96 seconds).

CONCLUSIONS

Use of this new subtraction algorithm would result in considerable savings in the time required to review images and in improved sensitivity to subtle focal pathology.

Patterns of accidental craniocerebral injury occurring in early childhood

OBJECTIVE

To describe the range of intracranial injuries encountered in 0-2-year-olds in cases of accidental head injury where the mechanism of trauma was well characterised and to assess the clinical consequences.

DESIGN

A retrospective review of imaging and clinical data.

SETTING

Two tertiary paediatric referral centres.

PATIENTS

All children aged 0-2 undergoing cranial CT as indicated by National Institute for Health and Clinical Excellence guidance for head injury from 2006 to 2011. After exclusion criteria, 149 patients were included.

MAIN OUTCOME MEASURES

Rates of skull fracture, intracranial haemorrhage, parenchymal injuries and ischaemic change per type of mechanism of injury. Rates of neurological sequelae on follow-up.

RESULTS

Skull fractures were demonstrated in 54 (36%) patients of whom 17 (11%) had thin underlying subdural haemorrhage (SDH). Extradural haemorrhage complicated one fracture and two cases of isolated subdural haematomas were seen without skull fracture. Radiologically evident brain parenchymal injuries were present in three patients, all with mechanisms of injury involving high levels of force; severe neurological sequelae were only seen in one patient, who had diffuse hypoxic-ischaemic damage at presentation and whose (accidental) mechanism of injury involved extensive acceleration/deceleration/translational forces.

CONCLUSIONS

Skull fractures and focal SDH are relatively common following minor trauma in this age group but in the vast majority of cases there are no long-term neurological sequelae. Conversely, diffuse brain injury with severe subsequent neurological impairment was only seen in patients with a correspondingly severe mechanism of injury.

Silica-rubber microstructure visualised in three dimensions by focused ion beam-scanning electron microscopy

A focused ion beam-scanning electron microscope (FIB-SEM) technique for three-dimensional reconstruction and representation of material microstructures was applied to a silica-filled synthetic rubber for the first time. Backscattered electron imaging allowed differentiation between rubber matrix, silica filler and zinc oxide (used as an activator for the sulphur vulcanisation reaction). Subsequent image processing allowed three-dimensional isosurface model generation of the particulate structure within the rubber composite and separation of zinc oxide from the silica filler. The potential for development and application of this technique using finite element analysis modelling is also highlighted.

FEA MODELING OF SCHALLAMACH WAVES

The term Schallamach wave is used to describe a wave of detachment that sometimes arises during the frictional sliding of a smooth rubber surface against a smooth rigid surface. Extensive experimental investigations have been made since Schallamach first observed the waves in 1971; however, no successful finite element analysis (FEA) modeling of the behavior has been reported yet. This work uses an explicit dynamics FEA approach to model both the initiation and progression of waves of detachment for the first time. The use of the finite element method allows for the detailed stress and strain analysis at the interface to be examined. Here, the limitations of using a purely elastic solution in plane-strain are explored. To validate the explicit dynamics approach for modeling the Schallamach waves, another biaxial compressive buckling mode has also been modeled.

Cyclic Stress Relaxation (Csr) of Filled Rubber and Rubber Components

Under repeated stressing it is well known that rubber materials exhibit cyclic stress relaxation (CSR). Previous work has shown that the amount of relaxation observed from cycle to cycle is significantly greater than that expected from static relaxation measurements. The reduction in the stress attained on the second and successive loading cycles as compared to the stress attained on the first cycle in a stress strain cyclic test of fixed amplitude has been measured for elastomer test pieces and engineering components. It is seen that the peak force, under cyclic testing to a specific maximum displacement, plotted against the number of cycles on logarithmic scales produces a straight line graph, whose slope correlates to the rate of cyclic stress relaxation per decade. The rate of cyclic stress relaxation was found to increase with displacement amplitude in all modes of deformation. Plotting the rate of stress relaxation per decade against the maximum average strain energy attained in the cycle reduces the data measured in different deformation modes for both simple test pieces and components to a single curve. This approach allows the cyclic stress relaxation in a real component to be predicted from simple laboratory tests.

Systematic review: tolerable amount of gluten for people with coeliac disease

BACKGROUND

The threshold amount of gluten in 'gluten-free' products that can be tolerated by people with coeliac disease is unclear.

AIM

To investigate the threshold amount of gluten and the threshold concentration of gluten in food products that can be tolerated by people with coeliac disease.

DESIGN

Systematic review of studies published between 1966 and May 2007.

METHODS

The data sources used were MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of retrieved articles. We included studies that evaluated the amount of dietary gluten or the concentrations of gluten in food products that can be tolerated by people with coeliac disease whatever their design, method or language of publication.

RESULTS

Thirteen studies (three randomized controlled, one cohort, two crossover, and seven cross-sectional) met the inclusion criteria. The daily amount of tolerable gluten varied widely between studies. Whilst some patients tolerated an average of 34-36 mg of gluten per day, other patients who consumed about 10 mg of gluten per day developed mucosal abnormalities. The effect of the consumption of 'gluten-free' products with different degrees of gluten contamination was also inconsistent.

CONCLUSIONS

The amount of tolerable gluten varies among people with coeliac disease. Although there is no evidence to suggest a single definitive threshold, a daily gluten intake of <10 mg is unlikely to cause significant histological abnormalities.

Electronic properties of the interface between p-CuI and anatase-phase n-TiO2 single crystal and nanoparticulate surfaces: A photoemission study

We present a study of the growth of the p-type inorganic semiconductor CuI on n-type TiO2 anatase single crystal (101) surfaces and on nanoparticulate anatase surfaces using synchrotron radiation photoemission spectroscopy. Core level photoemission data obtained using synchrotron radiation reveal that both the substrate (TiO2) and the overlayer (CuI) core levels shift to a lower binding energy to different degrees following the growth of CuI on TiO2. Valence band photoemission data show that the valence band maximum of the clean substrate differs from that of the dosed surface which may be interpreted qualitatively as due to the introduction of a new density of states within the band gap of TiO2 as a result of the growth of CuI. The valence band offset for the heterojunction n-TiO2p-CuI has been measured using photoemission for both nanoparticulate and single crystal TiO2 surfaces, and the band energy alignment for these heterojunction interfaces is presented. With the information obtained here, it is suggested that the interface between p-CuI and single crystal anatase-phase n-TiO2 is a type-II heterojunction interface, with significant band bending. The measured total band bending matches the work function change at the interface, i.e., there is no interface dipole. In the case of the nanoparticulate interface, an interface dipole is found, but band bending within the anatase nanoparticles remains quite significant. We show that the corresponding depletion layer may be accommodated within the dimension of the nanoparticles. The results are discussed in the context of the functional properties of dye-sensitized solid state solar cells.

Enteral nutrition for maintenance of remission in Crohn's disease

BACKGROUND

Prevention of relapse is a major issue in the management of Crohn's disease. Corticosteroids and 5-ASA preparations are not effective for the maintenance of remission. Methotrexate, infliximab, 6-mercaptopurine and its prodrug, azathioprine may be effective in maintaining remission, but these drugs may cause significant adverse events.

OBJECTIVES

To conduct a systematic review to evaluate the efficacy of enteral nutrition for the maintenance of remission in Crohn's disease.

SEARCH STRATEGY

MEDLINE (1966 to January 2007), EMBASE (1984 to January 2007) the Cochrane Central Register of Controlled Trials from the Cochrane Library (Issue 4, 2006) and the IBD/FBD Review Group Specialized Trials Register were searched. The articles cited in each publication were hand searched.

SELECTION CRITERIA

Randomised controlled trials which compared enteral nutrition with no intervention, placebo or with any other intervention were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of included studies were independently performed by two authors. The main outcome measure was the occurrence of clinical or endoscopic relapse as defined by the primary studies. Odds ratios and 95% confidence intervals were calculated for dichotomous outcomes.

MAIN RESULTS

Two studies were identified that met the inclusion criteria and were included in the review. Statistical pooling of the results of these studies was not possible because the control interventions, and the way outcomes were assessed differed greatly between the two studies. In one study (Takagi 2006), patients who received half of their total daily calorie requirements as elemental diet and the remaining half by normal diet had a significantly lower relapse rate compared to patients who received unrestricted normal diet (9 of 26 versus 16 of 25; OR 0.3, 95% CI 0.09 to 0.94). In the other study (Verma 2001), elemental and polymeric feeds (providing between 35 and 50% of patients' pretrial calorie intake in addition to unrestricted normal food) were equally effective for maintenance of remission and allowing withdrawal of steroid therapy (8 of 19 versus 6 of 14; OR 0.97, 95% CI 0.24 to 3.92).

AUTHORS' CONCLUSIONS

The available evidence suggests that supplementary enteral nutritional may be effective for maintenance of remission in Crohn's disease. Whilst larger studies are needed to confirm these findings, enteral nutritional supplementation could be considered as an alternative or as an adjunct to maintenance drug therapy in Crohn's disease.

Recycled Rubber: The Rubber Granulate - Virgin Rubber Interface

Reusing granulates derived from old tire stock and other sources in high tech engineering applications is still considered a high risk option. In addition to ensuring that the granulates are correctly identified, it is important to know how the incorporation of these materials alters the intrinsic flaw size of a finished product and to see how much the strength of the interface between these materials and the virgin materials compares to the basic strength of the virgin stock and the granulates. This paper explores possible techniques that can examine both properties so that an informed evaluation of the effect of reincorporating granulates can be established in practice.

Tumour necrosis factor alpha blocking agents for induction of remission in ulcerative colitis

BACKGROUND

Anti-TNF-alpha agents have been shown to be effective for the induction of remission in Crohn's disease. The role of TNF-alpha blocking agents in ulcerative colitis is, however, unclear and recent studies have yielded conflicting results.

OBJECTIVES

To evaluate the efficacy of TNF-alpha antibody for induction of remission in ulcerative colitis, and to determine adverse events associated with TNF-alpha antibody treatment.

SEARCH STRATEGY

We searched MEDLINE (1966 to 2005), EMBASE (1984 to 2005), the Cochrane Central Register of Controlled Trials (Issue 3, 2004) and the IBD/FBD Review Group Specialized Trials Register. We hand-searched the articles cited in each publication.

SELECTION CRITERIA

Only randomised controlled trials in which patients with active ulcerative colitis (defined by a combination of clinical, radiographic, endoscopic and histologic criteria) were randomly allocated to receive a TNF-alpha blocking agent in the treatment arm, and to receive placebo or another treatment in the comparison arm were included.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of each study were independently performed by two reviewers. Any disagreement among reviewers was resolved by consensus. The main outcome measure was the occurrence of remission as defined by the primary studies. Other endpoints were clinical, histological or endoscopic improvement as defined by the primary studies; improvement in quality of life as measured by a validated quality of life tool and the occurrence of adverse events.

MAIN RESULTS

Seven randomised controlled trials were identified that satisfied the inclusion criteria. In patients with moderate to severe ulcerative colitis whose disease was refractory to conventional treatment using corticosteroids and/or immunosuppressive agents, infliximab (three intravenous infusions at 0, 2, and 6 weeks) was more effective than placebo in inducing clinical remission (Relative Risk (RR) 3.22, 95% CI 2.18 to 4.76); inducing endoscopic remission (RR 1.88, 95% CI 1.54 to 2.28); and in inducing clinical response (RR 1.99, 95% CI 1.65 to 2.41) at 8 weeks. A single infusion of infliximab was also more effective than placebo in reducing the need for colectomy within 90 days after infusion (RR 0.44, 95% CI 0.22 to 0.87).

AUTHORS' CONCLUSIONS

In patients with moderate to severe ulcerative colitis whose disease is refractory to conventional treatment using corticosteroids and/or immunosuppressive agents, infliximab is effective in inducing clinical remission, inducing clinical response, promoting mucosal healing, and reducing the need for colectomy at least in the short term. Serious adverse events attributable to infliximab were not common in the included studies but physicians should be aware of and be prepared to deal with potential adverse events such as anaphylactic reactions and infections.

Tumour necrosis factor alpha blocking agents for induction of remission in ulcerative colitis

BACKGROUND

Anti-TNF-alpha agents have been shown to be effective for the induction of remission in Crohn's disease. The role of TNF-alpha blocking agents in ulcerative colitis is, however, unclear and recent studies have yielded conflicting results.

OBJECTIVES

To evaluate the efficacy of TNF-alpha antibody for induction of remission in ulcerative colitis, and to determine adverse events associated with TNF-alpha antibody treatment.

SEARCH STRATEGY

We searched MEDLINE (1966 to 2005), EMBASE (1984 to 2005), the Cochrane Central Register of Controlled Trials (Issue 3, 2004) and the IBD/FBD Review Group Specialized Trials Register. We hand-searched the articles cited in each publication.

SELECTION CRITERIA

Only randomised controlled trials in which patients with active ulcerative colitis (defined by a combination of clinical, radiographic, endoscopic and histologic criteria) were randomly allocated to receive a TNF-alpha blocking agent in the treatment arm, and to receive placebo or another treatment in the comparison arm were included.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of methodological quality of each study were independently performed by two reviewers. Any disagreement among reviewers was resolved by consensus. The main outcome measure was the occurrence of remission as defined by the primary studies. Other endpoints were clinical, histological or endoscopic improvement as defined by the primary studies; improvement in quality of life as measured by a validated quality of life tool and the occurrence of adverse events.

MAIN RESULTS

Seven randomised controlled trials were identified that satisfied the inclusion criteria. In patients with moderate to severe ulcerative colitis whose disease was refractory to conventional treatment using corticosteroids and/or immunosuppressive agents, infliximab (three intravenous infusions at 0, 2, and 6 weeks) was more effective than placebo in inducing clinical remission (Relative Risk (RR) 3.22, 95% CI 2.18 to 4.76); inducing endoscopic remission (RR 1.88, 95% CI 1.54 to 2.28); and in inducing clinical response (RR 1.99, 95% CI 1.65 to 2.41) at 8 weeks. A single infusion of infliximab was also more effective than placebo in reducing the need for colectomy within 90 days after infusion (RR 0.44, 95% CI 0.22 to 0.87).

AUTHORS' CONCLUSIONS

In patients with moderate to severe ulcerative colitis whose disease is refractory to conventional treatment using corticosteroids and/or immunosuppressive agents, infliximab is effective in inducing clinical remission, inducing clinical response, promoting mucosal healing, and reducing the need for colectomy at least in the short term. Serious adverse events attributable to infliximab were not common in the included studies but physicians should be aware of and be prepared to deal with potential adverse events such as anaphylactic reactions and infections.

Does gastrostomy tube feeding in children with cerebral palsy increase the risk of respiratory morbidity?

BACKGROUND

Children with severe neurological impairment may have significant oral motor dysfunction and are at increased risk of nutritional deficiencies, poor growth, and aspiration pneumonia. Gastrostomy tube feeding is increasingly being used for nutritional support in these children.

AIM

To examine the occurrence of respiratory morbidity before and after gastrostomy feeding tube insertion in children with severe neurological disabilities.

METHODS

This study was nested in a longitudinal, prospective, uncontrolled, multicentre cohort study designed to investigate the outcomes of gastrostomy tube feeding in 57 children with severe neurological disabilities. Parents completed a questionnaire prior to (visit 1) and 6 and 12 months (visits 2 and 3) following the gastrostomy, detailing number of chest infections requiring antibiotics and/or hospital admission.

RESULTS

Mean number of chest infections requiring antibiotics was 1.8 on visit 1 and 0.9 on visit 3. Hospital admissions for chest infections fell significantly from 0.5 to 0.09.

CONCLUSION

This study provides no evidence for an increase in respiratory morbidity following insertion of a feeding gastrostomy in children with cerebral palsy.

Growth in children with Helicobacter pylori infection and dyspepsia

AIMS

To compare the height, weight, and body mass index (BMI) of children presenting with dyspeptic symptoms and Helicobacter pylori infection, to those with dyspepsia but without the infection.

METHODS

A retrospective chart review of 257 children was performed. 13C urea breath test was performed to detect H pylori infection; weight and height were recorded and BMI was calculated. Weight, height, and BMI SD scores were determined using the 1990 UK normative data. The Index of Multiple Deprivation 2004 (IMD 2004) scores, which measure deprivation at small area level, were calculated from the patients' postcodes.

RESULTS

Ninety seven of the 257 children were H pylori positive. The mean age at diagnosis and presenting symptoms of H pylori positive and negative patients were similar. The mean IMD 2004 scores for children with H pylori infection were significantly higher compared to H pylori negative patients, suggesting that children with the infection came from relatively more deprived areas. The mean weight and height SD score were significantly lower for children with H pylori infection compared to those without. However, this difference was no longer significant after adjusting for socioeconomic deprivation and ethnic differences between the groups.

CONCLUSION

Children with dyspepsia and H pylori infection were shorter and lighter than patients with similar symptoms but no infection. The differences in anthropometry may be due to socioeconomic and ethnic factors rather than H pylori infection.

Interventions for growth failure in childhood Crohn's disease

BACKGROUND

Crohn's disease in childhood is a chronic relapsing condition. Fifteen to forty per cent of children with Crohn's disease have growth retardation (Griffiths 1993a). Some treatment modalities including corticosteroids have been implicated in growth failure but it is thought mainly to be secondary to uncontrolled disease activity (Motil 1993; Markowitz 1993). Growth is fundamental to the practice of pediatrics, so by taking growth as the primary outcome measure we address issues important to both patients, their families and pediatricians.

OBJECTIVES

To evaluate the effectiveness of the different modalities available for the treatment of childhood Crohn's disease with regard to the reversal of growth failure and the promotion of normal growth.

SEARCH STRATEGY

Searches were made of the following databases using the Collaborative Review Group Search Strategy: EMBASE (1984-2004), MEDLINE (1966-2004), The Cochrane Central Register of Controlled Trials, The Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialized Trials Register and the Science Citation Index. Abstracts from the major gastrointestinal research meetings and references from published articles were also reviewed.

SELECTION CRITERIA

Randomized controlled trials pertaining to children less than 18 years of age with Crohn's disease were selected. Those with growth as an outcome measure were included in the review.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of the methodological quality of each trial was independently reviewed by two reviewers. Only one good quality randomized controlled trial was included in the review and therefore no statistical analysis was possible.

MAIN RESULTS

Three randomized controlled trials were identified. One was of good methodological quality (Markowitz 2000). This study looked at the use of 6-mercaptopurine (6-MP) as a steroid sparing agent. No difference in linear growth was observed between the intervention and placebo groups, although the total steroid dose received over the 18 month follow up period was reduced in the group receiving 6-MP. The two remaining randomized controlled trials (Sanderson 1987; Thomas 1993a) consider the use of enteral feeding versus corticosteroids for induction of remission, with height velocity standard deviation score at 6 months as an outcome measure. Although of less rigorous methodological quality, the results of these studies are discussed in detail in the review. In both studies height velocity standard deviation scores were significantly increased in the enteral feeding group compared with the corticosteroid group.

AUTHORS' CONCLUSIONS

In addition to these randomized controlled trials, a body of lower quality evidence does exist relevant to two other important interventions; the use of supplemental enteral nutrition (Morin 1980; Belli 1988; Israel 1995) and the judicious use of surgical interventions in pre-pubertal children with refractory disease (Alperstein 1985; Lipson 1990; McLain 1990). Newer treatments, such as infliximab, are now becoming more widely used and may offer advantages in promoting growth. These effects are as yet unstudied. This review highlights the need for large, multi centre studies of the different treatment options in paediatric Crohn's disease and the importance of standardised measurements of growth, such as height velocity standard deviation scores and height standard deviation scores as outcome measures.

New Technique for Measurement of Rubber-to-Metal Bond Failure

A new test, involving combined pure and simple shear, that can produce failure very close to the interface between the rubber and the bonding agent in a rubber-to-metal joint, is described. The test allows changes in the position of the tip of the de-bonded region to be followed with time, enabling the failure rate to be determined. The latter can be related to the strain energy release rate so that a fracture mechanics based analysis can be applied. Failure characteristics can be correlated with features of the de-bond surface. The results suggest that even when failure is very close to the interface, the measured strength is similar to that of the rubber.

Gastrostomy feeding versus oral feeding alone for children with cerebral palsy

BACKGROUND

Children with cerebral palsy (CP) can be significantly disabled in terms of their ability to suck, chew and swallow. This can lead to significant impairment in feeding ability and, eventually, to under-nutrition. It can also result in aspiration of food into the lungs. Feeding time may be considerably increased and, instead of being an enjoyable experience, mealtimes may be distressing for both the child and carer. Increasingly for children unable to maintain a normal nutritional state feeding by mouth, gastrostomy or jejunostomy tubes are being used to provide the digestive system with nutrients. A gastrostomy tube is a feeding tube inserted surgically through the abdominal wall directly into the stomach. A jejunostomy feeding tube is inserted into the jejunum, part of the small intestine, either directly or via a previous gastrostomy. Although gastrostomy or jejunostomy placement may greatly facilitate feeding of children with CP, many carers find it very difficult to accept this intervention emotionally. The treatment is also relatively costly. For all of these reasons, its effectiveness requires assessment.

OBJECTIVES

To assess the effects of nutritional supplementation given via gastrostomy or jejunostomy in children with feeding difficulties due to cerebral palsy.

SEARCH STRATEGY

We searched the Cochrane Library's register of controlled trials (CENTRAL) up to Issue 4, 2003, MEDLINE 1977 - December 2003, EMBASE 1980 - December 2003, CINAHL 1982 - December 2003, LILACS 1980 - end 2003, ASLIB 1983 - 2003 and Dissertation Abstracts 1980 - 2003.

SELECTION CRITERIA

Only randomised controlled trials which compared delivery of nutrition via a gastrostomy or jejunostomy tube compared with oral feeding alone for children up to the age of 16 were considered for this review.

DATA COLLECTION AND ANALYSIS

Selection of trials, data extraction and assessment of trial quality were undertaken independently by two reviewers.

MAIN RESULTS

No trials were identified that met the inclusion criteria for this review.

REVIEWERS' CONCLUSIONS

On the basis of this systematic review, considerable uncertainty about the effects of gastrostomy for children with cerebral palsy remains. A well designed and conducted randomised controlled trial should be undertaken to resolve the current uncertainties about medical management for children with cerebral palsy and physical difficulties in eating.

Low serum concentrations of insulin-like growth factor-I in children with active Crohn disease: effect of enteral nutritional support and glutamine supplementation

Dept. of Paediatric Gastroenterology, Central Manchester Hospital, Manchester, UK.

Contributions of Time Dependent and Cyclic Crack Growth to the Crack Growth Behavior of Non Strain-Crystallizing Elastomers

Engineering components are observed to fail more rapidly under cyclic loading than under static loading. This reflects features of the underlying crack growth behavior. This behavior is characterized by the relation between the tearing energy, T, and the crack growth per cycle, dc/dn. The increment of crack growth during each cycle is shown here to result from the sum of time dependent and cyclic crack growth components. The time dependent component represents the crack growth behavior that would be present in a conventional constant T crack growth test. Under repeated stressing additional crack growth, termed the cyclic crack growth component, occurs. For a non-crystallizing elastomer, significant effects of frequency have been found on the cyclic crack growth behavior, reflecting the presence of this cyclic element of crack growth. The cyclic crack growth behavior over a wide range of frequencies was investigated for unfilled and swollen SBR materials. The time dependent crack growth component was calculated from constant T crack growth tests and the cyclic contribution derived from comparison with the observed cyclic growth. It is shown that decreasing the frequency or increasing the maximum tearing energy during a cycle results in the cyclic crack growth behavior being dominated by time dependent crack growth. Conversely at high frequency and at low tearing energy, cyclic crack growth is dominated by the cyclic crack growth component. A large effect of frequency on cyclic crack growth behavior was observed for highly swollen SBR. The cyclic crack growth behavior was dominated by the time dependent crack growth component over the entire range of tearing energy and/or crack growth rate. The origin of the cyclic component may be the formation/melting of quasi crystals at the crack tip, which is absent at fast crack growth rates in the unswollen SBR and is absent at all rates in the swollen SBR.

Chlamydial infection and unplanned pregnancy in women with ready access to health care

OBJECTIVE

To apply urine-based ligase chain reaction for Chlamydia trachomatis (C. trachomatis) and Neisseria gonorrhoeae (N. gonorrhoeae) detection and standard urine-based pregnancy testing for Navy-enlisted women, and to compare the prevalence and epidemiologic correlates of these adverse reproductive outcomes.

METHODS

Participants were surveyed and urine was collected for pregnancy testing using standard laboratory methods and detection of C. trachomatis and N. gonorrhoeae infection by ligase chain reaction. Self-administered surveys facilitated collection of demographics, sexual behavior, including contraceptive use, sexual partners, sexually transmitted disease, and pregnancy history.

RESULTS

Among 299 of 314 participants, the prevalence of chlamydial infection was 4.7% and of pregnancy was 9.7%, with 48.3% of the pregnancies unplanned. Chlamydia trachomatis infection was univariately associated with having a new sex partner within the last 6 months, more sexual partners, single marital status, condom use, drinking until passing out or vomiting in the past 30 days (alcohol misuse), and current pregnancy. Unplanned pregnancy was univariately associated with young age, single marital status, inconsistent condom use, having a new sex partner within the last 6 months, and more recent sexual partners. Among the pregnant women, four (13.8%) were infected with C. trachomatis.

CONCLUSION

The high rates of chlamydial infection and unplanned pregnancy found in this population of employed young women with ready access to health care and health education underscore the challenge of enhancing reproductive health via compliance with effective contraceptive and sexually transmitted disease prevention methods. This is a challenge that remains unmet.

Neuroprotection mediated by glutamate carboxypeptidase II (NAALADase) inhibition requires TGF-beta

Inhibition of glutamate carboxypeptidase (GCP) II (EC 3.4.17.21), also termed N-acetylated alpha-linked acidic dipeptidase (NAALADase), has been shown to protect against ischemic injury presumably via decreasing glutamate and increasing N-acetyl-aspartyl-glutamate (NAAG). NAAG is a potent and selective mGlu3 receptor agonist. Activation of glial mGlu3 receptors has been shown to protect against NMDA toxicity by releasing transforming growth factors, TGF-betas. We hypothesized that GCP II inhibition could be neuroprotective also via TGF-betas, due to increased NAAG. To verify this, Enzyme-Linked Immunosorbent Assays (ELISAs) were performed on media from both control and ischemic cultures treated with the GCP II inhibitor, 2-(phosphonomethyl)-pentanedioic acid (2-PMPA). We found that 2-PMPA attenuated ischemia-induced declines in TGF-beta. To further assess the role of TGF-betas in 2-PMPA-mediated neuroprotection, a neutralizing antibody to TGF-beta (TGF-beta Ab) was used. In both in vitro and in vivo models of cerebral ischemia, TGF-beta Ab reversed the neuroprotection by 2-PMPA. Antibodies to other growth factors had no effect. Data suggests that neuroprotection by GCP II inhibition may be partially mediated by promoting TGF-beta release.

Neuroprotection afforded by NAAG and NAALADase inhibition requires glial cells and metabotropic glutamate receptor activation

N-acetylated-alpha-linked-acidic-dipeptidase (NAALADase or glutamate carboxypeptidase II) cleaves the neuropeptide N-acetyl-aspartyl-glutamate (NAAG) to glutamate and N-acetyl-aspartate (NAA). Previously, NAAG and 2-(phosphonomethyl)-pentanedioic acid (2-PMPA), a potent and selective NAALADase inhibitor, were found to be neuroprotective in neuronal/glial co-cultures and in animals following transient middle cerebral artery occlusion. In this report, we examined the involvement of glial cells and metabotropic glutamate (mGlu) receptors in neuroprotection mediated by NAAG and 2-PMPA in an in vitro model of metabolic inhibition. Neuroprotection of neuronal/glial co-cultures by both NAAG and 2-PMPA, against metabolic inhibition, was significantly higher than neuroprotection in the absence of glia. Similarly, (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG IV), a selective group II mGlu receptor agonist, was less neuroprotective in the absence of glia. Selective group II mGlu receptor antagonists and (S)-alpha-methyl-4-carboxyphenylglycine (MCPG), a non-selective mGlu receptor antagonist, reduced the protection afforded by both NAAG and 2-PMPA when using neuronal/glial co-cultures. In contrast, groups I and III mGlu receptor antagonists did not affect NAAG or 2-PMPA neuroprotection. These results underscore the critical involvement of glia and group II mGlu receptors in NAAG and 2-PMPA-mediated neuroprotection.

Quality of life in inflammatory bowel disease: a cross-cultural comparison of English and Canadian children

BACKGROUND

Any disease and its treatment has an important impact on health-related quality of life for affected individuals. There have been few previous studies on the quality of life for children with inflammatory bowel disease (IBD).

METHODS

A cross-cultural comparison was performed to determine whether the concerns of children with IBD in the United Kingdom are ranked similarly to those of children with IBD in Canada. An item reduction questionnaire, developed from interviews with Canadian children with IBD, was scored by 53 British children with IBD for importance and frequency, as a questionnaire had been scored previously by 117 Canadian children.

RESULTS

There was a significant correlation between the mean scores (r = 0.831, P < 0.001) and ranks (r = 0.801, P < 0.001) for the 96 questions, and 43 of the 50 highest-ranking concerns corresponded for both populations. Confidence interval analysis showed a significant difference between the mean values for 21 of the 96 items; 20 of these 21 were ranked higher in the United Kingdom than they had been in Canada, suggesting that the frequency and/or degree of concern was greater for the British children with IBD.

CONCLUSIONS

Health-related concerns of British children with Crohn disease and ulcerative colitis correlate closely with those of Canadian children with those diseases. Further studies are needed to determine the sensitivity of individual questions, the most appropriate wording of these questions, and the optimal length for a proposed instrument to assess quality of life in children with IBD.

High-Speed Fracture of Elastomers: Part I

The fracture behavior of elastomers has been studied in the high speed region immediately above a transition region where a change in the nature of the fracture surface occurs. A video camera operating at up to 6000 frames/s was used to follow the progress of failure. The test pieces employed were of the pure shear or tensile strip (with edge crack) varieties employed in earlier tear studies; in order to attain the high energy release rates required they were usually pre-strained and then cut to initiate the crack growth. The materials studied included various strain crystallizing and non-crystallizing elastomers, with different glass-transition temperatures, including natural rubber in normal, cis—trans isomerized or partially-epoxidized forms, a butadiene—acrylonitrile copolymer, a styrene—butadiene copolymer and ethylene—propylene co- and ter-polymers. The use of a fracture mechanics approach based on the strain energy release rate enables results for different test piece geometries to be brought into agreement in the region above the transition. Fracture energies in this region correlate well with viscoelastic properties, but the potential for strain crystallization to strengthen is not exhibited. This is presumably because at the high failure rates involved, the loading time at the crack tip is insufficient to allow significant crystallization to occur. The correlation with viscoelastic behavior suggests that the material around the propagating tip is still essentially rubbery in its behavior, although the fracture surfaces in the high speed region have a smooth, “glassy” appearance. Further evidence of this is provided by effects of crosslink type and density and filler type and loading, where again the effects seen in the high speed failure region parallel those observed below the transition. An effect of thickness on fracture properties appears to be absent in the high speed region, by contrast with behavior at lower energies and at the transition itself. This supports the view that the fracture surface roughness that develops in the lower energy region is due to the initiation of a process akin to cavitation by through-the-thickness stresses near the crack tip. The transition is found to vary with pressure and temperature, as well as thickness, in a way that does not correlate with viscoelastic changes but may reflect changes in the through-the-thickness stresses. The existence of a limiting crack speed is illustrated and discussed. Fracture under large biaxial deformations, where higher crack speeds are observed, will be discussed in Part II.

N-Acetylated alpha-linked acidic dipeptidase converts N-acetylaspartylglutamate from a neuroprotectant to a neurotoxin

We previously reported that inhibition of the brain enzyme N-acetylated alpha-linked acidic dipeptidase (NAALADase; glutamate carboxypeptidase II) robustly protects cortical neurons from ischemic injury. Since NAALADase hydrolyzes N-acetylaspartylglutamate (NAAG) to glutamate we hypothesized that inhibiting NAALADase would both decrease glutamate and increase NAAG. Increasing NAAG is potentially important because NAAG is a metabotropic glutamate receptor agonist and an N-methyl-D-aspartate (NMDA) partial antagonist, both of which have previously been shown to be neuroprotective. To understand the likely effects of endogenous NAAG in the central nervous system, we have now investigated the activity of NAAG in primary cortical cultures while manipulating NAALADase activity. Under hydrolyzing conditions, when NAALADase was active, NAAG had toxic effects that were blocked by NMDA and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonists and by NAALADase inhibition. NAAG's toxic effects were presumably due to the liberation of glutamate. Under nonhydrolyzing conditions, when NAALADase was inhibited, NAAG demonstrated neuroprotective effects against both NMDA toxicity and metabolic inhibition. In the case of NMDA-induced toxicity, NAAG provided neuroprotection through its partial antagonist activity at the NMDA receptor. In the case of metabolic inhibition, NAAG had an additional neuroprotective effect mediated through its agonist properties at the type II metabotropic glutamate receptor. These results indicate that NAAG might play an important role in the central nervous system, under certain pathological conditions, as a neurotoxin or as a neuroprotectant, depending on the activity of NAALADase.

Technical aspects of feeding the disabled child

Children with neurological impairment frequently have difficulties in consuming sufficient energy and other nutrients to maintain adequate nutritional status. Under-nutrition is a significant contributory factor to growth failure. Eating may be distressing and time-consuming for the child and carer. Aspiration of feeds is common and may predispose to chronic chest infections. Gastro-oesophageal reflux is also common and may contribute to significant morbidity. This paper discusses some of the issues involved in the nutritional management of neurologically impaired children.

Breast cancer education program based in Asian grocery stores

Culturally and linguistically compatible university students were trained as community health educators to provide breast cancer education and screening information to shoppers at Asian grocery stores. Information about early detection of breast cancer was shared with 8,877 women, who reported speaking 40 different languages. Baseline surveys were completed by 1,202 women; 779 took part in the follow-up survey. The survey questions assessed baseline knowledge, attitudes, and screening behaviors regarding breast cancer, tested the efficacy of the intervention, and sought barriers to accessing screening services. Screening adherence at baseline was low, but reported screening compliance had increased by follow-up. This study confirms the cost-effectiveness of student health educators and Asian grocery store sites as venues to reach the diverse age, ethnic, and socioeconomic segments of the Asian community, while demonstrating the community's receptiveness to the dissemination of health information and introducing bilingual students to health education and research careers.

Black cosmetologists promoting health program: pilot study outcomes

BACKGROUND

African Americans suffer a disproportionate burden of illness and premature mortality.

METHODS

A health education program delivered via cosmetologists was pilot tested as a supplement to other programs seeking to reach this community with information designed to remedy this inequality. Eight cosmetologists were randomized to either an active or a passive educational intervention arm, with the active arm (experimental arm) focused on breast cancer early detection.

RESULTS

Both cosmetologists and clients found this an acceptable intervention. Nearly all women in the study demonstrated that they had heard the mainstream messages about the value of breast cancer early detection, but a considerable proportion appeared not to realize breast cancer's high level of morbidity and mortality within their own community.

CONCLUSION

The results suggest this approach is worthy of further evaluation.

Double-blind randomized controlled trial of glutamine-enriched polymeric diet in the treatment of active Crohn's disease

BACKGROUND

Glutamine is traditionally considered a nonessential amino acid but may be conditionally essential in patients with catabolic conditions. Glutamine-supplemented foods in these patients have been shown to prevent deterioration of gut permeability, protect against the development of intestinal mucosal atrophy, and improve nitrogen balance. Animal models of inflammatory bowel disease suggest that glutamine-enriched enteral diets may lead to less severe intestinal damage, less weight loss, improved nitrogen balance, and reduced disease activity. The purpose of the current study was to compare the efficacy of a glutamine-enriched polymeric diet with a standard low-glutamine polymeric diet in the treatment of active Crohn's disease.

METHODS

Eighteen children with active Crohn's disease were randomly assigned to receive a 4-week course of either a standard polymeric diet with a low glutamine content (4% of amino acid composition; group S) or a glutamine-enriched polymeric diet (42% of amino acid composition; Group G). The two diets were isocaloric and isonitrogenous with an identical essential amino acid profile. Remission rates were analysed on an intent-to-treat basis. Changes in clinical and laboratory parameters of disease activity were also compared after 4 weeks of nutritional treatment.

RESULTS

Two of the children, both in group G, were withdrawn from the trial because of nontolerance of the diet. There was no difference between the two groups in proportion of patients achieving remission (intent-to-treat basis): 5 (55.5%) of 9 in group S versus 4 (44.4%) of 9 in group G (p = 0.5). Improvement in mean paediatric Crohn's disease activity index (PCDAI) was significantly more in group S (p = 0.002) but changes in orosomucoid level, platelet count, and weight were not different between the groups.

CONCLUSIONS

The findings suggest that a glutamine-enriched polymeric diet offers no advantage over a standard low-glutamine polymeric diet in the treatment of active Crohn's disease. Rather, it appears to be less effective in improving PCDAI. The reported beneficial effects of glutamine seen in many catabolic states must be viewed with caution when extrapolating to the management of Crohn's disease.

Selective inhibition of NAALADase, which converts NAAG to glutamate, reduces ischemic brain injury

We describe here a new strategy for the treatment of stroke, through the inhibition of NAALADase (N-acetylated-alpha-linked-acidic dipeptidase), an enzyme responsible for the hydrolysis of the neuropeptide NAAG (N-acetyl-aspartyl-glutamate) to N-acetyl-aspartate and glutamate. We demonstrate that the newly described NAALADase inhibitor 2-PMPA (2-(phosphonomethyl)pentanedioic acid) robustly protects against ischemic injury in a neuronal culture model of stroke and in rats after transient middle cerebral artery occlusion. Consistent with inhibition of NAALADase, we show that 2-PMPA increases NAAG and attenuates the ischemia-induced rise in glutamate. Both effects could contribute to neuroprotection. These data indicate that NAALADase inhibition may have use in neurological disorders in which excessive excitatory amino acid transmission is pathogenic.

Indentation Tests on Elastomer Blocks

The problem of indentation hardness for elastomer blocks has been examined at two levels. Initially an examination of the geometric non-linearity was undertaken. It was observed that the empirical equations adopted by the various standards organizations to predict the stiffness relationships were not always applicable. It appears that the classical Hertz solution to the problem gives a better representation of the general behavior. A finite element approach was also adopted here to tackle the large displacement problem and the limitations of this approach have been discussed. This geometric problem is further complicated in practice by the effect of the finite thickness of the elastomer sheet. This problem has also been analyzed and a suitable general relationship proposed to account for the finite thickness effects. The second problem examined is how the effects of the non-linear elasticity of the material can be tackled. It is shown that the form of the elastic stored energy function at small strains influences the indentation behavior.

Toxicity induced by a polyglutamated folate analog is attenuated by NAALADase inhibition

Folates have been shown to be neurotoxic and convulsive. Endogenously, folates exist in the brain in a polyglutamated form with 1-7 terminal glutamates (approx. 1 microM). The brain enzyme N-acetylated alpha-linked acidic dipeptidase (NAALADase) has been shown to remove sequentially the gamma-linked glutamates from folic acid polyglutamates. We report that, at high concentrations (300 microM-30 mM), a folic acid hexaglutamate analog is dose-dependently toxic to dissociated rat cortical cultures and that this toxicity is reversed by 2-PMPA, a potent and selective NAALADase inhibitor. These data suggest a new mechanism for folic acid toxicity.