A Curvature-Enhanced Random Walker Segmentation Method for Detailed Capture of 3D Cell Surface Membranes

High-resolution 3D microscopy is a fast advancing field and requires new techniques in image analysis to handle these new datasets. In this work, we focus on detailed 3D segmentation of Dictyostelium cells undergoing macropinocytosis captured on an iSPIM microscope. We propose a novel random walker-based method with a curvature-based enhancement term, with the aim of capturing fine protrusions, such as filopodia and deep invaginations, such as macropinocytotic cups, on the cell surface. We tested our method on both real and synthetic 3D image volumes, demonstrating that the inclusion of the curvature enhancement term can improve the segmentation of the aforementioned features. We show that our method performs better than other state of the art segmentation methods in 3D images of Dictyostelium cells, and performs competitively against CNN-based methods in two Cell Tracking Challenge datasets, demonstrating the ability to obtain accurate segmentations without the requirement of large training datasets. We also present an automated seeding method for microscopy data, which, combined with the curvature-enhanced random walker method, enables the segmentation of large time series with minimal input from the experimenter.

QuimP: analyzing transmembrane signalling in highly deformable cells

Summary

Transmembrane signalling plays important physiological roles, with G protein-coupled cell surface receptors being particularly important therapeutic targets. Fluorescent proteins are widely used to study signalling, but analyses of image time series can be challenging, in particular when cells change shape. QuimP software semi-automatically tracks spatio-temporal patterns of fluorescence at the cell membrane at high spatial resolution. This makes it a unique tool for studying transmembrane signalling, particularly during cell migration in immune or cancer cells for example.

Availability and implementation

QuimP (http://warwick.ac.uk/quimp) is a set of Java plugins for Fiji/ImageJ (http://fiji.sc) installable through the Fiji Updater (http://warwick.ac.uk/quimp/wiki-pages/installation). It is compatible with Mac, Windows and Unix operating systems, requiring version >1.45 of ImageJ and Java 8. QuimP is released as open source (https://github.com/CellDynamics/QuimP) under an academic licence.

Supplementary information

Supplementary data are available at Bioinformatics online.

Discordance in latent tuberculosis (TB) test results in patients with end-stage renal disease

OBJECTIVES

This natural experiment was designed to assess the impact of exposure to an active case of tuberculosis (TB) on a group of immunosuppressed individuals, with end-stage renal disease over an extended follow-up.

STUDY DESIGN

Close contacts of people with sputum smear-positive Mycobacterium tuberculosis are at high risk of infection, particularly immunosuppressed individuals. An infectious TB healthcare worker worked in a renal dialysis unit for a month before diagnosis, with 104 renal dialysis patients, was exposed for ≥8 h.

METHODS

Patients were informed and invited for screening 8-10 weeks postexposure. They either underwent standard two-step assessment with tuberculin skin test (TST) and QuantiFERON^®-TB Gold (Cellestis GmbH; QFN) interferon-gamma release assay (IGRA) or after consent, enrolled in a study where these two tests were performed simultaneously with T-SPOT^®-TB (Oxford Immunotec Ltd; TSPOT). Patients within the study were followed up for 2 years from exposure, with QFN and TSPOT repeated at months 3 and 6 from the first testing.

RESULTS

Of 104 exposed individuals, 75 enrolled in the study. There was a high degree of discordance among QFN, TSPOT and TST. This was seen at both the first time point and also over time in subjects who were retested. No patients had active TB at the baseline testing. None received treatment for latent TB infection. Over the following 2 years, no one developed TB disease.

CONCLUSION

This study suggests that there is a low risk of progression to active TB in low-incidence countries even in high-risk groups. This plus the degree of the test result discordance emphasises the complexities of managing TB in such settings as it is unclear which of these tests, if any, provides the best diagnostic accuracy.

Healing of Circular Defects in the Rabbit Medial Meniscus Can Occur Spontaneously and Is not Improved by Intra-Articular Hyaluronic Acid

The aim of this study was to determine the effects of intra-articular hyaluronic acid on meniscal healing. Circular defects, 1.0 mm in diameter, were made in the anterior third of the medial meniscus in rabbits. In one joint, 0.4 ml hyaluronic acid (Healon®) was instilled, and in the contralateral (control) joint, 0.4 ml Ringer’s saline. Four rabbits were killed after four, eight and 12 weeks and the menisci examined histologically. By eight weeks most of the lesions had healed by filling with hyaline-like cartilage. Healing was not improved by hyaluronic acid treatment. The repair tissue stained strongly with alcian blue, and the presence of type II collagen, keratan sulphate, and chondroitin sulphate was demonstrated by immunohistochemical localisation. In contrast to the circular defects, longitudinal incisions made in the medial menisci of a further six rabbits did not show any healing after 12 weeks, indicating that the shape of the lesion largely determined the potential for healing.

The effect of hyaluronic acid on meniscal healing was tested in a rabbit model. With one millimeter circular lesions in the medial meniscus, healing by filling with hyalinelike cartilage was not significantly affected by the application of hyaluronic acid intra-articularly at the time of surgery, compared to saline controls, as assessed histologically four, eight and 12 weeks after the operation.

A prospective cohort study assessing the appearance of retrieved aesthetic orthodontic archwires

OBJECTIVES

To investigate the appearance of three esthetic nickel titanium (NiTi) wires after 6 weeks of intra-oral cycling and to determine the association between objective and subjective measures of esthetics.

SETTING AND SAMPLE POPULATION

A prospective cohort study was undertaken involving participants undergoing upper fixed orthodontic appliance treatment with ceramic brackets.

MATERIALS AND METHODS

Fifty participants were assigned to one of three groups of NiTi esthetic wires (American Orthodontics Ever White™, Forestadent Biocosmetic™ and GAC High Aesthetic™), with wires retrieved after 6 weeks in situ. Participants completed a bespoke questionnaire exploring perceptions of wire esthetics. Objective measurement of coating loss was undertaken using a custom arch wire jig.

RESULTS

American Orthodontics Ever White™ had the greatest mean coating loss (50.7%) followed by Forestadent Biocosmetic™ (6%), with GAC High Aesthetic TM undergoing minimal loss (0.07%) (P < .001). The majority of coating loss with the American Orthodontics Ever White™ wires arose in the anterior region while Forestadent Biocosmetic™ wires and GAC High Aesthetic™ wires exhibited coating loss posteriorly (P < .001). These findings were reflected in the subjective assessment with a negative correlation found between coating loss and final Visual Analogue Scale scores (P < .001).

CONCLUSIONS

Considerable esthetic variation between arch wires following 6 weeks of intraoral cycling was identified in this prospective cohort study. Intraoral cycling has a negative impact on participant perception of arch wire esthetics, and objective and subjective assessment of wire esthetics appears to be consistent.

Image based modeling of bleb site selection

Cells often employ fast, pressure-driven blebs to move through tissues or against mechanical resistance, but how bleb sites are selected and directed to the cell front remains an open question. Previously, we found that chemotaxing Dictyostelium cells preferentially bleb from concave regions, where membrane tension facilitates membrane-cortex detachment. Now, through a novel modeling approach based on actual cell contours, we use cell geometry to predict where blebs will form in migrating cells. We find that cell geometry alone, and by implication, physical forces in the membrane, is sufficient to predict the location of blebs in rounded cells moving in a highly resistive environment. The model is less successful with more polarized cells moving against less resistance, but can be greatly improved by positing a front-to-back gradient in membrane-cortex adhesion. In accord with this prediction, we find that Talin, which links membrane and cortex, forms such a front-to-back gradient. Thus our model provides a means of dissecting out the role of physical forces in controlling where blebs form, and shows that in certain circumstances they could be the major determining factor.

Ochromobactrum intermedium: an emerging opportunistic pathogen-case of recurrent bacteraemia associated with infective endocarditis in a haemodialysis patient

We describe the first clinical case report of infective endocarditis related to Ochrobactrum intermedium infection. The case involved a 23-year-old man receiving dialysis via an internal jugular long-term haemodialysis catheter. He improved with a prolonged course of meropenem and minocycline. Ochrobactrum spp. are recognized as rare emerging opportunistic pathogens.

Septic arthritis of the temporomandibular joint as a complication of acute otitis media in a child: A rare case and the importance of real-time PCR for diagnosis

We document the case of a 7-year-old boy who presented with pain in his left ear and trismus after a diagnosis of acute otitis media one week previously. His blood inflammatory markers were raised and magnetic resonance imaging (MRI) showed significant left temporomandibular joint effusion and partial attenuation of the left mastoid. A clinical diagnosis of septic arthritis of the TMJ was made and the patient was commenced on broad-spectrum antibiotics. Analysis using real time PCR enabled identification of the offending organism, confirmation of the diagnosis and antibiotic treatment to be specifically tailored for treatment.

Raised levels of metal ions in the blood in patients who have undergone uncemented metal-on-polyethylene Trident-Accolade total hip replacement

The issues surrounding raised levels of metal ions in the blood following large head metal-on-metal total hip replacement (THR), such as cobalt and chromium, have been well documented. Despite the national popularity of uncemented metal-on-polyethylene (MoP) THR using a large-diameter femoral head, few papers have reported the levels of metal ions in the blood following this combination. Following an isolated failure of a 44 mm Trident-Accolade uncemented THR associated with severe wear between the femoral head and the trunnion in the presence of markedly elevated levels of cobalt ions in the blood, we investigated the relationship between modular femoral head diameter and the levels of cobalt and chromium ions in the blood following this THR. A total of 69 patients received an uncemented Trident-Accolade MoP THR in 2009. Of these, 43 patients (23 men and 20 women, mean age 67.0 years) were recruited and had levels of cobalt and chromium ions in the blood measured between May and June 2012. The patients were then divided into three groups according to the diameter of the femoral head used: 12 patients in the 28 mm group (controls), 18 patients in the 36 mm group and 13 patients in the 40 mm group. A total of four patients had identical bilateral prostheses in situ at phlebotomy: one each in the 28 mm and 36 mm groups and two in the 40 mm group. There was a significant increase in the mean levels of cobalt ions in the blood in those with a 36 mm diameter femoral head compared with those with a 28 mm diameter head (p = 0.013). The levels of cobalt ions in the blood were raised in those with a 40 mm diameter head but there was no statistically significant difference between this group and the control group (p = 0.152). The levels of chromium ions in the blood were normal in all patients. The clinical significance of this finding is unclear, but we have stopped using femoral heads with a diameter of ≤ 36 mm, and await further larger studies to clarify whether, for instance, this issue particularly affects this combination of components.

Gas-phase CO2 subtraction for improved measurements of the organic aerosol mass concentration and oxidation degree by an aerosol mass spectrometer

The Aerodyne aerosol mass spectrometer (AMS) has been widely used for real-time characterization of the size-resolved chemical composition of sub-micrometer aerosol particles. The first step in AMS sampling is the pre-concentration of aerosols while stripping away the gas-phase components, which contributes to the high sensitivity of this instrument. The strength of the instrument lies in particle phase measurement; however, ion signals generated from gas-phase species can influence the interpretation of the particle-phase chemistry data. Here, we present methods for subtracting the varying contributions of gas-phase carbon dioxide (CO2) in the AMS spectra of aerosol particles, which is critical for determining the mass concentration and oxygen-to-carbon (O/C) ratio of organic aerosol. This report gives details on the gaseous CO2 subtraction analysis performed on a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) data set acquired from sampling of fresh and diluted vehicle emissions. Three different methods were used: (1) collocated continuous gas-phase CO2 measurement coupled with periodic filter tests consisting of sampling the same particle-free air by the AMS and the CO2 analyzer, (2) positive matrix factorization (PMF) analysis to separate the gas- and particle-phase signals of CO2(+) at m/z 44, and (3) use of the particle time-of-flight (PTOF) size-resolved chemical information for separation of gas- and particle-phase signals at m/z 44. Our results indicate that these three different approaches yield internally consistent values for the gas/particle apportionment of m/z 44, but methods 2 and 3 require certain conditions to be met to yield reliable results. The methods presented are applicable to any situation where gas-phase components may influence the PM signal of interest.

A prospective study comparing contamination rates between a novel mid-stream urine collection device (Peezy) and a standard method in renal patients

INTRODUCTION

It is imperative that laboratories receive uncontaminated urine samples to avoid giving false-positive results and reduce antimicrobial use.

AIM

The aim of the study was to investigate a novel urine collection device (Peezy) in a renal outpatient clinic to determine whether it reduced contamination of urine samples.

METHODS

The novel device was used in 420 renal transplant recipients and the results were compared with 424 matched historical controls, who used the standard method of urine collection. High epithelial cell counts on microscopy and mixed urine cultures were used to identify contaminated samples.

RESULTS

Peezy increased the rates of both epithelial cells and mixed growths in the urine samples when compared with the historical controls.

CONCLUSIONS

Further randomised studies in other more generalisable populations need to be performed.

Characterisation of amyloid-induced inflammatory responses in the rat retina

Amyloid-induced inflammation is thought to play a critical and early role in the pathophysiology of Alzheimer's disease. As such, robust models with relevant and accessible compartments that provide a means of assessing anti-inflammatory agents are essential for the development of therapeutic agents. In the present work, we have characterised the induction of inflammation in the rat retina following intravitreal administration of amyloid-beta protein (Aβ). Histology and mRNA endpoints in the retina demonstrate Aβ1-42-, but not Aβ42-1-, induced inflammatory responses characterised by increases in markers for microglia and astrocytes (ionised calcium-binding adaptor molecule 1 (iba-1), GFAP and nestin) and increases in mRNA for inflammatory cytokines and chemokines such as IL1-β, MIP1α and TNFα. Likewise, analysis of vitreal cytokines also revealed increases in inflammatory cytokines and chemokines, including IL1-β, MIP1α and MCP1, induced by Aβ1-42 but not Aβ42-1. This profile of pro-inflammatory gene and protein expression is consistent with that observed in the Alzheimer's disease brain and suggest that this preclinical model may provide a useful relevant tool in the development of anti-inflammatory approaches directed towards Alzheimer's disease therapy.

External quality assessment scheme for parasite serology; a review of the scheme design and performance

Background

An external quality assessment (EQA) scheme for parasite serology was introduced in April 2005 as a tool to measure how well laboratories were performing in parasite serodiagnosis.

Aim and Methods

To review the scheme design and performance from its beginning until January 2008.

Results

The numbers of participating laboratories gradually increased during the review period and was 28 in January 2008. The results showed that the standard of reporting was extremely high and there was an encouraging trend towards improvement in the overall percentage of correct reports. The most common error made was the returning of false negative results for Strongyloides antibodies.

Conclusion

It is hoped that this scheme will lead to a more standardised approach to the serological diagnosis of parasitic infection.

Persistent alanine aminotransferase elevations in children with parenteral nutrition-associated liver disease

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) is a serious condition affecting many children with short bowel syndrome. The aim of this study was to longitudinally assess serum alanine aminotransferase (ALT), a marker for hepatocyte injury, in enterally fed children with PNALD.

METHODS

Retrospective chart review of 31 patients treated from 1999 to 2006 by the Center for Advanced Intestinal Rehabilitation at Children's Hospital Boston (Mass). Inclusion criteria included PN duration of greater than 3 months with subsequent tolerance of full enteral nutrition and evidence of PN-associated liver injury. Time to normalize ALT and direct bilirubin were estimated using Kaplan-Meier and Cox proportional hazards methods.

RESULTS

Mean age PN cessation was 6 months (range, 2-14 months). Median PN duration was 18 weeks (interquartile range [IQR], 13-33 weeks), and median follow-up was 24 weeks (IQR, 14-48 weeks). After transition to full enteral nutrition, 74% of children normalized direct bilirubin, whereas only 50% normalized ALT. Kaplan-Meier median time to direct bilirubin and ALT normalization were 13 weeks and 35 weeks, respectively (P = .001).

CONCLUSION

Children with PNALD who have achieved PN independence have persistent ALT elevation despite normal direct bilirubin levels. This implies that hepatic injury may be ongoing beyond the time of bilirubin normalization in this cohort of patients.

Methodological issues related to assessing and measuring quality of life in patients with cancer: implications for patient care

Consideration of quality-of-life issues by all members of the healthcare team is essential in caring for people with cancer. In cancer research, quality of life is generally classified as health-related quality of life or individual quality of life. This paper discusses the instruments used to measure quality-of-life outcomes, and the relevance of such findings for healthcare staff in planning and providing effective and patient-centred care. Visual analogue scales (VASs) and questionnaires are commonly used to measure quality of life; however, both types of instruments are criticized because the content may not be relevant to individual patients, and do not distinguish differences between statistical and clinical significances in the findings. Using a combination of questionnaires and VASs may overcome some of these criticisms. In order to interpret the difference between statistical and clinical significance of findings and the associated implications for patient care, a mixed-methods approach to data collection is recommended in quality-of-life studies. This provides meaning and understanding to the quantitative data and individual perspectives on patients' experiences of having cancer. Information from such studies may also be more effective in helping healthcare staff identify relevant issues when planning cancer care services at individual, local and national level.

Immune effects of decreasing low-molecular weight hemoglobin components of hemoglobin-based oxygen carriers (HBOC) in a swine model of severe controlled hemorrhagic shock

Hemoglobin-based oxygen carriers (HBOCs) show potential as safe, efficacious, pre-hospital resuscitation fluids. The major criticism of HBOC-201 is its vasoactive property, attributed partially to low-molecular weight (low-MW) tetrameric/dimeric (TD) hemoglobin (Hb) in HBOC solution. Here we sought to determine whether resuscitation with decreasing concentrations of low-MW Hb component of HBOC affects immune responses in hemorrhagic swine. 28 anesthetized swine underwent a soft muscle crush and controlled hemorrhage of 55% blood volume, followed by resuscitation with HBOC containing 31%, 2%, or 0.4% low-MW Hb in four 10 ml/kg infusions at 20, 30, 45 and 60 minutes before hospital arrival at 75 minutes. IL-10, cell activation and adhesion markers and CD4:CD8 ratio remained unchanged in all 3 groups compared to baseline. Leukocyte apoptosis was equally elevated across all groups. Purification from 31% to 0.4% low-MW Hb in HBOC solution did not alter immune effects in a swine model of severe controlled hemorrhagic shock.

Growth and nutritional status in infants with short-bowel syndrome after the serial transverse enteroplasty procedure

BACKGROUND & AIMS

The aim of this study was to describe the long-term nutritional outcomes of 4 patients with short bowel syndrome (SBS) who underwent a newly described bowel-lengthening procedure, the serial transverse enteroplasty (STEP) procedure.

METHODS

We performed a retrospective review of the medical records of 4 children who underwent STEP at 1 center. The primary outcome measure was the percentage of total dietary energy received by the enteral route before and after STEP. Other outcome measures were weight and height Z scores and body composition, as measured by arm anthropometric values.

RESULTS

Four children with SBS were identified, all of whom had been dependent on parenteral nutrition since birth. The mean preoperative follow-up period was 234 days (range, 63-502 days), and the mean postoperative follow-up period was 362 days (range, 252-493 days). By using model-based mean estimates, the mean enteral nutrition intake was 48% preoperatively vs 62% postoperatively (P = .02). The model mean weight for age Z score increased by .7 SDs postoperatively (P = .01), and the model mean weight for height increased by .6 SDs (P < .0001). The percent standard mid-upper-arm circumference increased by 13.1% postoperatively (P = .03), and the percent standard triceps skinfold increased by 24.5% postoperatively (P < .0001).

CONCLUSIONS

The STEP procedure was associated with improved growth and body composition among 4 children with SBS in the face of a decreasing need for parenteral nutrition. Among patients with refractory SBS and dilated small intestine, the STEP procedure is associated with improved clinical and nutritional outcomes in the first year after surgery.

Discrepancy in CD3-Transmembrane Peptide Activity between In Vitro and In Vivo T-Cell Inhibition

Electrostatic amino acid interactions between receptor subunits within the T-cell antigen receptor (TCR) transmembrane domain are critical for the formation of the TCR-CD3 complex. Core peptide, a short peptide corresponding to the TCR-alpha transmembrane region, containing two positively charged amino acids, is known to inhibit T-cell function in vitro and in vivo. The aim of this study was to examine peptides corresponding to the syntactic transmembrane CD3 region binding to TCR-alpha for their ability to inhibit T-cell activation in vitro and in vivo. Three peptides matching the transmembrane sequence of CD3-delta, -epsilon and -gamma were synthesized and tested in different biological in vitro and in vivo systems for their effect on T-cell activity. The CD3-peptides had no impact on T-cell function in vitro, but surprisingly, decreased signs of inflammation in the adjuvant arthritis rat model in vivo. Preliminary evidence suggests that peptides with CD3 transmembrane-derived sequences can inhibit an immune response as assessed by adjuvant-induced arthritis. The lack of in vitro activity may lead to a wasteful disregard of active compounds in the process of drug discovery and development.

Hormone-replacement therapy use, but not race, impacts the resting and exercise-induced GH response in postmenopausal women

OBJECTIVE

This study examined the effect of hormone-replacement therapy (HRT) use on the incremental GH response to aerobic exercise in postmenopausal women and established whether racial differences in the GH response were seen at rest and in response to exercise.

METHODS

13 white (n = 6, HRT; n = 7, no HRT) and seven black women (no HRT) were studied on two occasions, a control day and an exercise day (30 min at 70% VO(2)max on a cycle ergometer). Blood was sampled every 10 min for a 4-h period and analyzed for GH using an ultrasensitive chemiluminescent assay.

RESULTS

The mean 4-h GH concentration was higher on both study days in the HRT women than the non-HRT users. The integrated GH concentrations were greater in the HRT women both at rest and in response to exercise (rest, 352 +/- 53 min microg l(-1); exercise, 711 +/- 57 min microg l(-1); P < 0.01) than in the non-HRT women (rest, 157 +/- 87 min microg l(-1); exercise, 248 +/- 94 min microg l(-1)). The incremental GH response was greater in the HRT users than in the non-HRT women (358 +/- 130 versus 90.8 +/- 94 min microg l(-1), respectively; P < 0.05). GH-production rate during the 4-h period was greater in the HRT women than in the non-HRT women (P < 0.01), due to an increase in the GH mass secreted/pulse (P < 0.05), with no change in GH pulse number or GH half-life. No racial differences in the mean 4-h GH concentrations or integrated GH concentrations were found at rest or in response to exercise.

CONCLUSION

HRT use resulted in a greater incremental exercise response compared with non-HRT users, due to changes in the secretory pulse characteristics in the HRT users. This study also demonstrated that no racial differences exist at rest and in response to exercise in the morning hours.

The role of enteral nutrition in the reversal of parenteral nutrition-associated liver dysfunction in infants

BACKGROUND

Liver dysfunction in children dependent on parenteral nutrition (PN) is well established, and the extent of hyperbilirubinemia has been shown to correlate with morbidity and mortality. The aim of this study was to assess whether increasing provisions of enteral nutrition can improve PN-associated hyperbilirubinemia over time.

METHODS

A retrospective review was conducted on infants in our institution's Short Bowel Syndrome Clinic from 1999 to 2004. Inclusion criteria included PN duration more than 1 month, serum direct bilirubin more than 3 mg/dL while on PN, and tolerance of full enteral nutrition with eventual discontinuation of PN. Paired t tests were used for statistical analyses.

RESULTS

Twelve infants were identified with a PN duration of 5 +/- 1 months. Five patients underwent liver biopsy while on PN, and histological evidence of cholestasis was found on all specimens. Peak total and direct bilirubin levels were 10.5 +/- 1.9 and 7.0 +/- 1.6 mg/dL, respectively, and occurred at time of PN discontinuation. Only 2 patients had improvement in serum bilirubin levels before initiation of full enteral nutrition. After initiation of full enteral nutrition and discontinuation of PN, all patients achieved permanent normalization of bilirubin levels by 4 months (P < .05) after a 1-month plateau phase. Alkaline phosphatase levels approached reference range within this time but were not significant.

CONCLUSION

These data demonstrate for the first time that although PN-dependent infants can achieve normalization of marked hyperbilirubinemia with enteral nutrition, the improvement in liver function usually begins only after full enteral nutrition is tolerated and PN is withdrawn. These findings support the aggressive weaning of PN to enteral nutrition in infants with short bowel syndrome.

Glutamine supplementation in infants with gastrointestinal disease: A randomized, placebo-controlled pilot trial

OBJECTIVE

Glutamine (Gln) is a non-essential amino acid that plays an important role in energy metabolism for gastrointestinal epithelia and other cells with rapid turnover. We evaluated the effects of enteral supplementation with Gln in infants undergoing surgery for congenital or acquired gastrointestinal disease.

METHODS

This was a randomized, double-masked, controlled clinical trial.

RESULTS

Twenty infants were randomly assigned to receive Gln (n = 9) or placebo amino acid (n = 11), with a goal of supplemental amino acid intake of 0.4 g.kg(-1).d(-1). Infants were weaned from parenteral nutrition, and enteral feeds were started according to a standardized feeding protocol. Median (interquartile range) durations of parenteral nutrition were 39 d (12 to 99) in the Gln group and 21 d (6 to 59) in the control group (P = 0.201). Median (interquartile range) durations needed to reach 80% of the US recommended dietary allowance for energy with enteral nutrition were 24 d (8 to 55) in the Gln group and 12.5 d (5 to 32) in the control group (P = 0.313). There were no differences in the occurrence of infections between groups. Among all infants enrolled, significant correlations were found between duration of parenteral nutrition and residual small bowel length, peak concentrations of direct bilirubin, and alanine aminotransferase. Peak direct bilirubin was associated with longer duration of parenteral nutrition, shorter gestation, older age before feeds were started, shorter bowel length, and larger amounts of parenteral energy and protein intake.

CONCLUSIONS

In this pilot trial, enteral Gln supplementation was well tolerated among infants with surgical gastrointestinal disease. There was no effect observed on the duration of parenteral nutrition, tolerance of enteral feeds, or intestinal absorptive or barrier function. Larger, multicenter trials in infants with surgical gastrointestinal disease are needed due to the variability in important outcome measurements.

Nutrition for the pediatric office: update on vitamins, infant feeding and food allergies

PURPOSE OF REVIEW

Advances in the field of pediatric nutrition continue to help the pediatric office practitioner provide excellent clinical care to their patients. In 2003, several important papers were published in the field of clinical nutrition that are reviewed.

RECENT FINDINGS

New recommendations by the American Academy of Pediatrics for vitamin D supplementation for breast-fed infants have been published that underscore the importance of routine supplementation with 200 IU vitamin D per day. Vitamin K should be provided (0.5 to 1 mg intramuscularly) to all newborns. The authors also review original reports evaluating the role of long-chain polyunsaturated fatty acids in infant formulas, the duration of exclusive breast-feeding, and the natural history of food allergies. Some observational studies support exclusive breast-feeding for 6 months. Data concerning the efficacy of long-chain polyunsaturated fatty acids are conflicting but do support the safety of these additives.

SUMMARY

Regular supplementation with vitamin D, and newborn provision of vitamin K, are important nutritional interventions for infants and children.

Update on pediatric nutrition: breastfeeding, infant nutrition, and growth

Recent studies continue to point out the critical nature of a patient's nutritional status in helping to determine important health outcomes in pediatrics. We review recent data concerning the composition of breast milk and its adequacy to support infant growth in the first six months of life, as well as trials that support breastfeeding as an important method to delay or reduce the incidence of atopic diseases such as eczema, allergies, and asthma. Studies have also been published that show how physician education and training about breastfeeding can be optimized. Studies showing how nutritional status is measured (using standard anthropometric techniques as well as more modern measures of basal metabolic rate) are highlighted, as well as the role of micronutrient supplementation of patients with the human immunodeficiency virus infection and diarrheal diseases.

Effectiveness of a clinical practice guideline for parenteral nutrition: a 5-year follow-up study in a pediatric teaching hospital

OBJECTIVE

To determine the effectiveness of a clinical practice guideline (CPG) on the use of parenteral nutrition (PN) at a tertiary care pediatric hospital.

METHODS

Review of prospectively collected data on hospital-wide PN use 2 years before and 5 years after the establishment of the CPG. Effectiveness of the CPG was measured as the percentage of PN courses lasting fewer than 5 days and the number of PN starts per 1000 patient days.

RESULTS

During the study period, 5745 PN courses were administered. The mean (SD) number of PN starts per 1000 inpatient days was 8.86 (0.78) before the CPG and 9.54 (2.49) afterwards (p = .28). The percentage courses of PN lasting for fewer than 5 days declined from 26.3% before the CPG to 18.4% afterwards (p < .0001). A multivariate model confirmed that the rate of short-term PN starts declined after the CPG was issued. The mean (SD) number of PN courses shorter than 5 days in the 2 years before the CPG was 2.33 (0.42) per 1000 patient days versus 1.75 (0.45) in the 5 years after the CPG was instituted (p = .005), which is a 25% decline. The services with the highest volume of PN use showed the most significant decreases in short-term PN use. A cost savings to the hospital of more than $50,000 may have been realized.

CONCLUSIONS

In a large pediatric tertiary care hospital, a CPG was successfully deployed. CPGs can favorably affect the use rates and costs of parenteral nutrition.

Cysteine metabolism and whole blood glutathione synthesis in septic pediatric patients

OBJECTIVE

To investigate whole body in vivo cysteine kinetics and its relationship to whole blood glutathione (GSH) synthesis rates in septic, critically ill pediatric patients and controls.

DESIGN

Prospective cohort study.

SETTING

Multidisciplinary intensive care unit and pediatric inpatient units at a children's hospital.

PATIENTS

Ten septic pediatric patients and ten controls (children admitted to the hospital for elective surgery).

INTERVENTIONS

Septic patients (age, 31 months to 17 yrs) and controls (age, 24 months to 21 yrs) received a 6-hr primed, constant, intravenous tracer infusion of l-[1-13C]cysteine. Blood samples were obtained to determine isotopic enrichment of plasma cysteine and whole blood [1-13C]cysteinyl-glutathione by gas-chromatography mass spectrometric techniques. The plasma flux and oxidation rate of cysteine and the fractional and absolute synthesis rates of GSH were determined. Septic patients received variable protein and energy intake, as per routine clinical management, and controls were studied in the early postabsorptive state.

MEASUREMENTS AND MAIN RESULTS

Plasma cysteine fluxes were increased in the septic patients when compared with the controls (68.2 +/- 17.5 [sd] vs. 48.7 +/- 8.8 micromol x kg(-1) x hr(-1); p <.01), and the fraction of plasma cysteine flux associated with oxidative disposal was similar among the groups. The absolute rates of GSH synthesis in whole blood were decreased (p <.01) in the septic patients (368 +/- 156 vs. 909 +/- 272 micromol x L(-1) x day(-1)). The concentration of whole blood GSH also was decreased in the septic group (665.4 +/- 194 vs. 1059 +/- 334 microM; p <.01)

CONCLUSIONS

Whole blood glutathione synthesis rates are decreased, by about 60%, in critically ill septic children receiving limited nutritional support. Plasma cysteine fluxes and concentration of cysteine were increased in the septic patients, suggesting a hypermetabolic state with increased protein breakdown. The mechanisms whereby GSH synthesis rates are decreased in these patients are probably multifactorial, presumably involving an inflammatory response in the presence of limited nutritional support. The role of nutritional modulation and the use of cysteine prodrugs in maintaining GSH concentration and synthesis remain to be established.

Randomized trial comparing the efficacy of a novel manual breast pump with a standard electric breast pump in mothers who delivered preterm infants

OBJECTIVE

The benefits of human milk for preterm infants are widely recognized, yet technological advances in milk expression have been slow. We compared the efficacy of a standard electric pump (EP; Egnell) used in 94% of United Kingdom neonatal units with a novel manual pump (MP; Avent ISIS) designed to operate more physiologically by simulating the infant's compressive action on the areola during breastfeeding.

METHODS

We randomized 145 women who delivered infants of <35 weeks' gestation to use the MP or the EP and measured total milk volume expressed while using the randomized pump during the infant's hospital stay, pattern of milk output and creamatocrit of milk expressed during a test period in the second week, and pump characteristics by maternal questionnaire.

RESULTS

Mothers who used the EP, who frequently double pumped, showed shorter expression times but produced no more milk than mothers who used the MP. When both pumped sequentially, however, mothers who used the MP showed significantly greater milk flow and total volume over 20 minutes. Creamatocrit was unaffected by pump type. The MP was rated significantly higher than the EP on 5 major characteristics.

CONCLUSIONS

When compared on equal terms (sequential pumping), mothers who used the MP showed greater milk flow, perhaps reflecting more physiologic pump design. Even with double pumping, mothers who used the EP did not advantage their infants with greater milk production. We believe that this novel, effective MP, preferred by mothers and costing a fraction of the EP price, reflects a significant advance in milk expression for high-risk infants.breast pumps, randomized trial, preterm infants.

Randomized study comparing the efficacy of a novel manual breast pump with a mini-electric breast pump in mothers of term infants

The objective of this study was to compare the efficacy of a mini-electric pump (MEP) and a novel manual breast pump (MP) designed to operate more physiologically. Sixty term breastfeeding mothers used the MP and MEP in randomized order 8 weeks postpartum, expressing for 10 minutes from each breast. Milk volume, fat content, and pattern of milk flow were measured. Mothers rated pump characteristics by questionnaire. There was no significant difference in the milk volume or fat content when mothers used the pumps in randomized order. The MP was rated significantly better overall and more comfortable and pleasant to use. Significantly more mothers kept the MP than the MEP. Despite the greater complexity and expense of the MEP, the pumps showed similar efficacy. The MP was preferred by mothers. The novel, more physiological operation of the MP represents an advance in milk expression technology.

Quantitative analysis of the neuroendocrine-immune axis: linear modeling of the effects of exogenous corticosterone and restraint stress on lymphocyte subpopulations in the spleen and thymus in female B6C3F1 mice

The effects of exogenous corticosterone and restraint stress on the number and percentage of lymphocyte subpopulations in the spleen and thymus were evaluated. The data were used to generate linear models that describe the relationship between these parameters and the area under the corticosterone concentration vs time curve (AUC). Comparison of the models revealed that the number of nucleated cells in the spleen was decreased similarly by exogenous corticosterone and restraint (at equivalent corticosterone AUC values). However, exogenous corticosterone caused a greater decrease in cell number in the thymus than it did in the spleen. Corticosterone preferentially depleted CD4+CD8+ cells in the thymus, whereas the same corticosterone exposure produced by restraint stress did not. In the spleen, cell number for all major cell types was decreased by both treatments, but there were minor differences in the change in percentage of some subpopulations induced by exogenous corticosterone as compared to restraint. The models derived here provide quantitative data that indicate the magnitude of corticosterone and stress-induced effects on lymphocyte populations in the spleen and thymus. These results have mechanistic implications, and they may be useful in future efforts to extrapolate from mouse to human by completing a risk assessment parallelogram.

The Drosophila embargoed gene is required for larval progression and encodes the functional homolog of schizosaccharomyces Crm1

The CRM1 (Exportin 1) protein is a receptor for leucine-rich nuclear export signal sequences. We have molecularly characterized the Drosophila melanogaster embargoed (emb) gene and find that it encodes a product with 49 and 71% sequence identity to the fission yeast Schizosaccharomyces pombe and human CRM1 proteins, respectively. We show that expression of the emb cDNA is sufficient to suppress the growth phenotype of both conditional-lethal and null S. pombe crm1(-) mutant strains, suggesting that emb encodes the functional homologue of the S. pombe Crm1 protein. Through mutagenesis screens we have recovered a series of recessive lethal emb mutations. There is a substantial maternal contribution of emb mRNA and animals hemizygous for our emb alleles can develop to second instar larvae but persist at this stage and consistently fail to undergo the molt to the third instar stage. We see a nuclear accumulation of endogenous actin in the intestinal epithelial cells of the emb mutant larvae, consistent with a role for the emb gene product in nuclear export of actin protein.

The Drosophila tissue polarity gene starry night encodes a member of the protocadherin family

The tissue polarity genes control the polarity of hairs, bristles and ommatidia in the adult epidermis of Drosophila. We report here the identification of a new tissue polarity gene named starry night (stan). Mutations in this essential gene alter the polarity of cuticular structures in all regions of the adult body. The detailed polarity phenotype of stan on the wing suggested that it is most likely a component of the frizzled (fz) pathway. Consistent with this hypothesis, stan appears to be downstream of and required for fz function. We molecularly cloned stan and found that it encodes a huge protocadherin containing nine cadherin motifs, four EGF-like motifs, two laminin G motifs, and seven transmembrane domains. This suggests that Stan functions in signal reception, perhaps together with Fz.

The balance between isoforms of the prickle LIM domain protein is critical for planar polarity in Drosophila imaginal discs

The tissue polarity mutants in Drosophila include a set of conserved gene products that appear to be involved in the control of cytoskeletal architecture. Here we show that the tissue polarity gene prickle (pk) encodes a protein with a triple LIM domain and a novel domain that is present in human, murine, and Caenorhabditis elegans homologs which we designate PET. Three transcripts have been identified, pk, pkM, and sple, encoding 93-, 100-, and 129-kD conceptual proteins, respectively. The three transcripts span 70 kb and share 6 exons that contain the conserved domains. The pk and sple transcripts are expressed with similar tissue-specific patterns but have qualitatively different activities. The phenotypes of pk mutants, and transgenic flies in which the different isoforms are overexpressed show that the balance between Pk and Sple is critical for the specification of planar polarity. In addition, these phenotypes suggest a tessellation model in which the alignment of wing hairs is dependent on cell shape and need not reflect fine-grained positional information. Lack of both pk and sple transcripts gives a phenotype affecting the whole body surface that is similar to those of dishevelled and frizzled (fz) suggesting a functional relationship between pk and fz signaling.