Influence of type of dairy matrix micro- and macrostructure on in vitro lipid digestion.

Recent research indicates that the food matrix can influence digestion kinetics and uptake of nutrients, thus affecting human health. The aim of this study was to obtain knowledge on how variations in microstructure and texture of foods represented by four dairy products; (i) cheddar cheese, (ii) a homogenized cheddar cheese, (iii) a micellar casein and cream drink or (iv) a micellar casein and cream gel, all of identical nutrient ratios of protein : fat and calcium : fat, affect the in vitro digestibility kinetics of lipids. Rheology of the four dairy structures was measured at 10 °C and 37 °C before digestion, and during the gastric phase of in vitro digestion. During digestion cheddar cheese was most resistant to enzymatic and mechanical disintegration, followed by homogenized cheese, while both the drink and gel had low resistance and dissolved in the gastric juice. Particle size, fat droplet size and microstructure were assessed by light scattering and confocal microscopy during digestion. Significantly larger fat droplets were observed during digestion of the cheddar cheese sample. The release of free fatty acids during the initial intestinal digestion showed cheddar cheese to provide a significantly lower release than homogenized cheese, whereas the drink and gel both had significantly higher free fatty acid release. The results suggest that the cheese matrix resistance to degradation and its large fat droplets were responsible for a slower fat digestion.

Capsular Sparing Total Hip Replacement Technique Applied with a Dual-mobility Cup to Reduce Dislocations.

Regardless of the surgical approach used, dislocation remains a complication following total hip replacement. In recent years, newer technologies, such as the use of large femoral heads, have reduced the rate of postoperative dislocation. The combination of such technology, together with a soft tissue repair technique, may reduce the dislocation rate even further. A single surgeon performed 513 primary total hip replacements on 505 patients using a posterior approach utilizing a technique designed to spare the capsule. There were 257 males and 248 females. Age ranged from 39 to 92 years. Surgeries were performed from January 2012 to December 2015. Implants used were cementless dual-mobility cups and cementless femoral stems. In all cases, the posterior capsule was incised and retracted, but not excised. Following implant placement, the capsule was repaired using a fiber reinforced suture. The superior border of the capsular incision, just above the piriformis, was sutured to the superior capsule or gluteus minimus muscle. The intent of this repair was to completely incarcerate the femoral head. Patients were followed at two weeks, six weeks, three months, one year, three years, and five years. Follow up was one to five years post-implantation. The dislocation rate was zero. The combination of a large dual-mobility femoral head, combined with a soft tissue repair that spares the deep capsule, has the potential to significantly reduce dislocation rates when using the posterior approach to the hip.

Cord Blood Banking for Potential Future Transplantation.

This policy statement is intended to provide information to guide pediatricians, obstetricians, and other medical specialists and health care providers in responding to parents' questions about cord blood donation and banking as well as the types (public versus private) and quality of cord blood banks. Cord blood is an excellent source of stem cells for hematopoietic stem cell transplantation in children with some fatal diseases. Cord blood transplantation offers another method of definitive therapy for infants, children, and adults with certain hematologic malignancies, hemoglobinopathies, severe forms of T-lymphocyte and other immunodeficiencies, and metabolic diseases. The development of universal screening for severe immunodeficiency assay in a growing number of states is likely to increase the number of cord blood transplants. Both public and private cord blood banks worldwide hold hundreds of thousands of cord blood units designated for the treatment of fatal or debilitating illnesses. The procurement, characterization, and cryopreservation of cord blood is free for families who choose public banking. However, the family cost for private banking is significant and not covered by insurance, and the unit may never be used. Quality-assessment reviews by several national and international accrediting bodies show private cord blood banks to be underused for treatment, less regulated for quality control, and more expensive for the family than public cord blood banks. There is an unquestionable need to study the use of cord blood banking to make new and important alternative means of reconstituting the hematopoietic blood system in patients with malignancies and blood disorders and possibly regenerating tissue systems in the future. Recommendations regarding appropriate ethical and operational standards (including informed consent policies, financial disclosures, and conflict-of-interest policies) are provided for physicians, institutions, and organizations that operate or have a relationship with cord blood banking programs. The information on all aspects of cord blood banking gathered in this policy statement will facilitate parental choice for public or private cord blood banking.

Minimal invasive lung support via umbilical vein with a double-lumen cannula in a neonatal lamb model: a proof of principle.

PURPOSE: Acute respiratory distress syndrome, with the need for invasive mechanical ventilation (MV) remains a major cause of neonatal mortality and morbidity. Although venovenous extracorporeal lung support (VV-ECLS) has become a standard of care procedure in neonatal patients with acute pulmonary failure there are no reports regarding the use of a double-lumen cannula for extracorporeal minimal invasive lung support via the umbilical vein. METHODS: A neonatal lamb model was used (n = 3). Umbilical vein was cannulated with a double-lumen catheter allowing venovenous extracorporeal gas exchange. Cannula was positioned with its tip in the right atrium. VV-ECLS was started and ventilation was stopped. Providing oxygenation and CO2 removal solely through VV-ECLS hemodynamics, blood gases were measured. RESULTS: Total VV-ECLS without MV was applied to all three neonatal lambs. Time on venovenous ECLS was 60, 120 and 120 min. Initial pCO2 was 60, 56 and 65 mmHg compared to 31, 32 and 32 mmHg at the end of VV-ECLS. Initial pO2 was 30, 27 and 26 mmHg compared to 22, 19 and 23 mmHg. Initial lactate was 5, 10 and 3.7 mmol/l compared to 13.3, 12.6 and 11.3 mmol/l at the end of VV-ECLS. MAP at baseline was 51, 52 and 65 mmHg compared to 36, 38 and 41 mmHg at the end of VV-ECLS. In all three lambs inotropes were admitted to maintain MAD >35 mmHg. CONCLUSION: Even without mechanical ventilation we were able to sufficiently remove pCO2 with our new minimal invasive VV-ECLS using a double-lumen catheter via the umbilical vein, supporting the idea of a lung protective strategy in neonatal acute respiratory failure. pO2 was measured 22, 19 and 23 mmHg, respectively, at the end of VV-ECLS, at least partially caused by recirculation phenomenon, which could possibly be improved by different cannula design. Inotropic support was necessary during VV-ECLS to achieve targeted MAD > 35 mmHg. While technically feasible, this new approach might allow further research in the field of extracorporeal lung support and therefore will follow the concept of a lung protective strategy in acute neonatal respiratory failure.

"Awake Veno-arterial Extracorporeal Membrane Oxygenation" in Pediatric Cardiogenic Shock: A Single-Center Experience.

In pediatric patients with acute refractory cardiogenic shock (CS), extracorporeal membrane oxygenation (ECMO) remains an established procedure to maintain adequate organ perfusion. In this context, ECMO can be used as a bridging procedure to recovery, VAD or transplantation. While being supported by ECMO, most centers tend to keep their patients well sedated and supported by invasive ventilation. This may be associated with an increased risk of therapy-related morbidity and mortality. In order to optimize clinical management in pediatric patients with ECMO therapy, we report our strategy of veno-arterial ECMO (VA-ECMO) in extubated awake and conscious patients. We therefore present data of six of our patients with CS, who were treated by ECMO being awake without continuous analgosedation and invasive ventilation. Of these six patients, four were <1 year and two >14 years of age. Median time on ECMO was 17.4 days (range 6.9-94.2 days). Median time extubated, while receiving ECMO support was 9.5 days. Mean time extubated was 78 % of the total time on ECMO. Three patients reached full recovery of cardiac function on "Awake-VA-ECMO," whereas the other three were successfully bridged to destination therapy (VAD, heart transplantation, withdrawal). Four out of our six patients are still alive. Complications related to ECMO therapy (i.e., severe bleeding, site infection or dislocation of cannulas) were not observed. We conclude that "Awake-VA-ECMO" in extubated, spontaneously breathing conscious pediatric patients is feasible and safe for the treatment of acute CS and can be used as a "bridging therapy" to recovery, VAD implantation or transplantation.

Teaching About Genetics and Sickle Cell Disease In Fifth Grade.

ACKNOWLEDGMENTS: We are grateful to Laura McVittie Gray for her work on the development of the student activities described in this article. This work was made possible by a Science Education Partnership Award (SEPA), Grant Number R25RR020449, from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH). Additional support for this SEPA-funded project was provided by Grant Number UL1RR024131-01 from NCRR. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH. ABSTRACT: A 5-lesson, 5th-grade instructional unit, "Genetics and Sickle Cell Disease," was developed and tested as part of a 40-lesson curriculum entitled SEEK (Science Exploration, Excitement, and Knowledge): A Curriculum in Health and Biomedical Science for Diverse 4th and 5th Grade Students. The genetics lessons include hands-on activities (e.g., DNA extraction from cheek cells), a simulated plant genetics experiment, and a classroom visit by a person with sickle cell disease, as well as by a health care practitioner who works with sickle cell patients or a scientist specializing in genetics. The unit was tested with 82 5th-grade students at public elementary schools in Oakland, CA; 96% were racial and ethnic minorities. The comparison group consisted of 84 5th-grade Oakland students racially/ ethnically, academically, and socio-economically matched to those in the experimental group. Both groups completed a 20-question, multiple-choice pre/posttest covering science concepts, scientific process, lifestyle choices, and careers. The experimental group showed significant improvement on 13 of 20 questions (P<.05, t-tests) and on the test as a whole, whereas the comparison group did not show significant improvement either on any of the questions or on the test as a whole. The experimental group improved on 10 concept questions, 2 scientific process questions, and 1 lifestyle question. Teachers rated the educational value of the unit as 9.5 on a scale from 1 (low) to 10 (high). These results show that genetics and sickle cell disease can be taught successfully in 5th grade, although they are not typically covered at this level.

Determination of cardiac output by ultrasound dilution technique in infants and children: a validation study against direct Fick principle.

BACKGROUND: In critically ill children, monitoring of cardiac output (CO) is essential to guide haemodynamic management and facilitate cardiovascular therapy. The ultrasound dilution technique (UDT), a novel minimally invasive indicator method, was recently introduced to determine CO. We validated UDT against the 'gold standard' reference technique, the direct Fick principle, in infants and children. METHODS: Twenty-six children (median age: 6 yr 2 months; median weight: 19.2 kg) underwent diagnostic heart catheterization. In each child, CO was determined by the Fick principle using direct measurement of oxygen consumption and invasive oximetry. Consecutively, haemodynamically stable conditions provided; three independent measurements of CO were conducted with UDT. CO values were compared using bias and limits of agreement calculated using the Bland-Altman approach and linear regression analysis for the complete study group and for a subgroup with body weight <20 kg (n=14). RESULTS: The mean (standard deviation) CO values were 3.76 (1.73) litre min(-1) (range 1.38-6.97) for the direct Fick principle and 3.49 (1.72) litre min(-1) (range 1.31-7.00) for UDT. An excellent correlation (r=0.96) was found between both methods (P<0.0001). The Bland-Altman analysis demonstrated good clinical agreement with a mean bias of 0.26 litre min(-1), limits of agreement of -0.66 and 1.19 litre min(-1), and percentage error of 25.9%. Comparable results were obtained for patients <20 kg (mean bias=0.19 litre min(-1), percentage error=25.5%). CONCLUSIONS: CO measurements by UDT agree favourably with Fick-derived CO data and both techniques were found to be equivalent and interchangeable. UDT represents a valid and applicable method for repetitive CO determinations in infants and children.

Estimation of genetic parameters and detection of quantitative trait loci for metabolites in Danish Holstein milk.

Small components and metabolites in milk are significant for the utilization of milk, not only in dairy food production but also as disease predictors in dairy cattle. This study focused on estimation of genetic parameters and detection of quantitative trait loci for metabolites in bovine milk. For this purpose, milk samples were collected in mid lactation from 371 Danish Holstein cows in first to third parity. A total of 31 metabolites were detected and identified in bovine milk by using (1)H nuclear magnetic resonance (NMR) spectroscopy. Cows were genotyped using a bovine high-density single nucleotide polymorphism (SNP) chip. Based on the SNP data, a genomic relationship matrix was calculated and used as a random factor in a model together with 2 fixed factors (herd and lactation stage) to estimate the heritability and breeding value for individual metabolites in the milk. Heritability was in the range of 0 for lactic acid to >0.8 for orotic acid and ß-hydroxybutyrate. A single SNP association analysis revealed 7 genome-wide significant quantitative trait loci [malonate: Bos taurus autosome (BTA)2 and BTA7; galactose-1-phosphate: BTA2; cis-aconitate: BTA11; urea: BTA12; carnitine: BTA25; and glycerophosphocholine: BTA25]. These results demonstrate that selection for metabolites in bovine milk may be possible.

Concept of "awake venovenous extracorporeal membrane oxygenation" in pediatric patients awaiting lung transplantation.

In patients awaiting LuTx, MV and ECMO are often the last ways to create a bridge to LuTx. Both interventions are associated with a poor posttransplant outcome and survival rate. To improve the results of these patients, new "bridging-strategies" are necessary. Recent reports demonstrate promising results for the concept of "awake ECMO" in adult patients. To date, no data on this approach in pediatric patients have been available. We therefore describe the use of VV-ECMO as a treatment strategy for RF in awake pediatric patients. It presents our experiences with the first three children treated using this new concept. Mean amount of time on ECMO was 44 days (range, 11.5-109 days). Two patients were successfully bridged to their LuTx. Both are still alive without any recurrences (24 and three months following LuTx). One patient died before a further LuTx after 109 days on ECMO due to adenoviral infection. Although reintubation was necessary in two patients, and total time being awake while on ECMO was <50%, we conclude that the concept of "awake VV-ECMO" is feasible for the treatment of RF and can be used as a "bridging therapy" to LuTx.

Bases of social power, leadership styles, and organizational commitment.

Affective organizational commitment reflects the extent to which organizational members are loyal and willing to work toward organizational objectives (Meyer & Allen, 1997). In particular, affective organizational commitment holds very important implications at all organizational levels (e.g., turnover rates, performance, and citizenship behavior). Whereas previous research has evinced the positive influence of transformational and charismatic leadership styles on affective commitment toward the organization (Bass & Avolio, 1994), little is known with regard to the nature of this relationship. In line with the interpersonal power/interaction model, the present investigation aimed to investigate the mechanism at play between transformational leadership style and affective organizational commitment. Specifically, we hypothesized that transformational leadership style would increase affective organizational commitment through its effect on willingness to comply with soft bases of power. In two studies, we subjected the foregoing hypotheses to empirical scrutiny. In Study 1, the proposed mediation model was empirically supported with Italian employees in the public sector. Attesting to the robustness of our findings, Study 2 replicated the findings of Study 1 with Italian employees from the public and private sectors. In addition, Study 2 replicated Study 1 using a different measure of transformational leadership. Both Study 1 and Study 2 provided results consistent with our hypotheses. Specifically, the present paper reports empirical evidence that (1) the more participants report having a transformational leader, the more willing they become to comply with soft (but not harsh) power bases, (2) in turn, greater willingness to comply with soft (but not harsh) power bases increases one's affective organizational commitment. These findings provide additional support for the interpersonal power/interaction model and pave the way for new research directions.

Nuclear magnetic resonance metabonomics reveals strong association between milk metabolites and somatic cell count in bovine milk.

Somatic cell count (SCC) is associated with changes in milk composition, including changes in proteins, lipids, and milk metabolites. Somatic cell count is normally used as an indicator of mastitis infection. The compositional changes in protein and fat affect milk coagulation properties, and also the metabolite composition is thought to contribute to differential milk properties. Milk somatic cells comprise different cell types, which may contribute to differential milk metabolite fingerprints. In this study, milk from a relatively large number of individual cows, representing significant differences in SCC, were analyzed by nuclear magnetic resonance (NMR)-based metabonomics, and the milk metabolite profiles were analyzed for differences related to SCC. Global principal component analysis performed on 876 samples from 2 Danish dairy breeds and orthogonal projection of latent structures discriminant analysis performed on a smaller subset (n=70) representing high (SCC >7.2×10(5) cells/mL) and low (SCC <1.4×10(4) cells/mL) milk SCC identified latent variables, which could be attributed to milk with elevated SCC. In addition, partial least squares regression between the NMR milk metabolite profiles and SCC revealed a strong correlation. The orthogonal projection of latent structures discriminant analysis and partial least squares regressions pinpointed specific NMR spectral regions and thereby identification of milk metabolites that differed according to SCC. Relative quantification of the identified metabolites revealed that lactate, butyrate, isoleucine, acetate, and ß-hydroxybutyrate were increased, whereas hippurate and fumarate were decreased in milk with high levels of somatic cells.

Balloon valvuloplasty in the treatment of congenital aortic valve stenosis--a retrospective multicenter survey of more than 1000 patients.

BACKGROUND: The value of balloon valvuloplasty of the aortic valve in childhood is still under debate. OBJECTIVE: To evaluate the results of the procedure in a retrospective multicenter survey of a large cohort over a long time interval. METHODS: Retrospective analysis of 1004 patients with balloon valvuloplasty of the aortic valve performed between 9/1985 and 10/2006 at 20 centers in Germany, Austria and Switzerland. Amongst others, the following parameters were evaluated before and after the procedure as well as at the end of follow-up or before surgery: clinical status, left ventricular function, transaortic pressure gradient, degree of aortic regurgitation, freedom from re-intervention or surgery. PATIENTS: Patients from 1 day to 18 years of age with aortic valve stenosis were divided into four groups: 334 newborns (1-28 days); 249 infants (29-365 days); 211 children (1-10 years), and 210 adolescents (10-18 years). RESULTS: Median follow-up was 32 months (0 days to 17.5 years). After dilatation the pressure gradient decreased from 65 (± 24)mm Hg to 26 (± 16)mm Hg and remained stable during follow-up. The newborns were the most affected patients. Approximately 60% of them had clinical symptoms and impaired left ventricular function before intervention. Complication rate was 15% in newborns, 11% in infants and 6% in older children. Independently of age, 50% of all patients were free from surgery 10 years after intervention. CONCLUSIONS: In this retrospective multicenter study, balloon valvuloplasty of the aortic valve has effectively postponed the need for surgery in infants, children and adolescents up to 18 years of age.

[Transcatheter valve interventions for heart valve diseases]. / Kathetergestützte Therapie von Herzklappenfehlern.

Severe aortic stenosis is a significant source of morbidity and mortality among the aging population. Due to prohibitive surgical risk, many patients are not candidates for surgery. Therefore, transcatheter aortic valve implantation has emerged as a promising technology for treating this group of high risk patients. With increasing experience, this procedure can be performed successfully and safely in selected high risk patients. Nevertheless, before widespread use and application to lower risk patients the results of randomized studies are mandatory. Primary (degenerative) and secondary (functional) mitral regurgitation (MR) is an important cause of heart failure. The double orifice technique of mitral valve repair using the MitraClip® system is one of many transcatheter approaches to treat significant MR in patients at high risk for conventional surgery. This technique is effective in reducing MR severity in patients suffering from both degenerative and functional MR. Percutaneous pulmonary valve implantation (PPVI) is an interventional treatment for adolescents and young adults with congenital heart disease. After corrective or palliative operation in infancy or early childhood, some patients regularly need reoperations for right ventricular outflow tract reconstruction. In the last decade, PPVI has evolved as an alternative treatment option with much less morbidity compared to repeated surgery.

NMR-based metabonomics reveals relationship between pre-slaughter exercise stress, the plasma metabolite profile at time of slaughter, and water-holding capacity in pigs.

Nuclear magnetic resonance (NMR)-based metabonomics was applied to investigate the effects of pre-slaughter exercise stress on the plasma metabolite profile at time of slaughter. The study included a total of 40 slaughter pigs, which were exposed to one of the following treatments: No pre-slaughter stress (control treatment), pre-slaughter exercise on a treadmill and subsequently 0, 1, or 3h rest prior to slaughter. NMR-based metabonomics revealed a clear difference in the plasma metabolite profile at time of slaughter between control pigs and pigs exercised without rest, which mainly could be ascribed to increased plasma lactate due to exercise. A resting period of 1 or 3h prior to slaughter reversed the stress-induced perturbations in the plasma metabolite profile. The plasma metabolite profile at time of slaughter was highly correlated with muscle temperature 1 min post-mortem, and a correlation to WHC was also demonstrated. Lactate was found to be the metabolite of importance for the association between the plasma metabolome and pH, temperature and WHC.

Methods to monitor distribution and metabolic activity of mesenchymal stem cells following in vivo injection into nucleotomized porcine intervertebral discs.

Intervertebral disc (IVD) degeneration involves a series of biochemical and morphological changes leading to loss of spinal stability and flexibility. Cell therapy is promising to reconstitute IVDs with new cells, however, sustained metabolic activity seems crucial for an active contribution to regeneration. The aim of the present study was to establish methods for separate follow up of persistence and activity of autologous porcine mesenchymal stem cells (pMSC) after implantation into IVDs of Goettingen minipigs in vivo in order to conclude about the potential of such an intervention strategy. For quantitative follow up, the transfer matrix was supplemented with Al(2)O(3) particles and pMSC which were retrovirally labeled with firefly luciferase (pMSC-Luc). Six mature Goettingen minipigs underwent matrix based cell transfer after partial nucleotomy of lumbar IVDs (n = 24). Day 0 and day 3 segments were analyzed for retained volume of Al(2)O(3) particles by micro-computed-tomography (muCT) and for cell activity by luciferase enzyme assessment. Three days after injection a reduction of Al(2)O(3) particles (P = 0.028) to about 9% and of pMSC-Luc activity to about 7% of initial values (P = 0.003) was detected, which suggests loss of 90% of the implant material under in vivo conditions without evidence for reduced pMSC-Luc metabolic activity (P = 0.887). In conclusion, separate follow up of implant material and cell activity was possible and unravels problems with in vivo implant persistence after annular puncture rather than quick loss of cell activity. Therefore, IVD-regeneration-strategies should increasingly focus on annulus reconstruction in order to reduce implant loss due to annular failure.

Rest before slaughter ameliorates pre-slaughter stress-induced increased drip loss but not stress-induced increase in the toughness of pork.

One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1-3h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs.

Mixed-linkage (1-->3,1-->4)-beta-D-glucan is a major hemicellulose of Equisetum (horsetail) cell walls.

Mixed-linkage (1-->3,1-->4)-beta-d-glucan (MLG) is a hemicellulose reputedly confined to certain Poales. Here, the taxonomic distribution of MLG, and xyloglucan, especially in early-diverging pteridophytes, has been re-investigated. Polysaccharides were digested with lichenase and xyloglucan endoglucanase (XEG), which specifically hydrolyse MLG and xyloglucan, respectively. The oligosaccharides produced were analysed by thin-layer chromatography (TLC), high-pressure liquid chromatography (HPLC) and alkaline peeling. Lichenase yielded oligo-beta-glucans from all Equisetum species tested (Equisetum arvense, Equisetum fluviatile, Equisetum scirpoides, Equisetum sylvaticum and Equisetum xtrachyodon). The major product was the tetrasaccharide beta-glucosyl-(1-->4)-beta-glucosyl-(1-->4)-beta-glucosyl-(1-->3)-glucose (G4G4G3G), which was converted to cellotriose by alkali, confirming its structure. Minor products included G3G, G4G3G and a nonasaccharide. By contrast, poalean MLGs yielded G4G3G > G4G4G3G > nonasaccharide > dodecasaccharide. No other pteridophytes tested contained MLG, including Psilotum and eusporangiate ferns. No MLG was found in lycopodiophytes, bryophytes, Chara or Nitella. XEG digestion showed that Equisetum xyloglucan has unusual repeat units. Equisetum, an exceedingly isolated genus whose closest living relatives diverged > 380 million years ago, has evolved MLG independently of the Poales. Equisetum and poalean MLGs share basic structural motifs but also exhibit clear-cut differences. Equisetum MLG is firmly wall-bound, and may tether neighbouring microfibrils. It is also suggested that MLG acts as a template for silica deposition, characteristic of grasses and horsetails.

Mixed-linkage beta-glucan : xyloglucan endotransglucosylase, a novel wall-remodelling enzyme from Equisetum (horsetails) and charophytic algae.

Mixed-linkage (1-->3,1-->4)-beta-d-glucan (MLG), a hemicellulose long thought to be confined to certain Poales, was recently also found in Equisetum; xyloglucan occurs in all land plants. We now report that Equisetum possesses MLG:xyloglucan endotransglucosylase (MXE), which is a unique enzyme that grafts MLG to xyloglucan oligosaccharides (e.g. the heptasaccharide XXXGol). MXE occurs in all Equisetum species tested (Equisetum arvense, Equisetum fluviatile, Equisetum hyemale, Equisetum scirpoides, Equisetum telmateia and Equisetum variegatum), sometimes exceeding xyloglucan endotransglucosylase (XET) activity. Charophytic algae, especially Coleochaete, also possess MXE, which may therefore have been a primordial feature of plant cell walls. However, MXE was negligible in XET-rich extracts from grasses, dicotyledons, ferns, Selaginella and bryophytes. This and the following four additional observations indicate that MXE activity is not the result of a conventional xyloglucan endotransglucosylase/hydrolase (XTH): (i) XET, but not MXE, activity correlates with the reaction rate on water-soluble cellulose acetate, hydroxyethylcellulose and carboxymethylcellulose, (ii) MXE and XET activities peak in old and young Equisetum stems, respectively, (iii) MXE has a higher affinity for XXXGol (K(m) approximately 4 microM) than any known XTH, (iv) MXE and XET activities differ in their oligosaccharide acceptor-substrate preferences. High-molecular-weight (M(r)) xyloglucan strongly competes with [(3)H]XXXGol as the acceptor-substrate of MXE, whereas MLG oligosaccharides are poor acceptor-substrates. Thus, MLG-to-xyloglucan grafting appears to be the favoured activity of MXE. In conclusion, Equisetum has evolved MLG plus MXE, potentially a unique cell wall remodelling mechanism. The prominence of MXE in mature stems suggests a strengthening/repairing role. We propose that cereals, which possess MLG but lack MXE, might be engineered to express this Equisetum enzyme, thereby enhancing the crop mechanical properties.

Electrical velocimetry for measuring cardiac output in children with congenital heart disease.

BACKGROUND: The purpose of this study was to evaluate the agreement of cardiac output measurements obtained by electrical velocimetry (CO(EV)) and those that derived from the direct Fick-oxygen principle (CO(F)) in infants and children with congenital heart defects. METHODS: Simultaneous measurements of CO(EV) and CO(F) were compared in 32 paediatric patients, aged 11 days to 17.8 yr, undergoing diagnostic right and left heart catheterization. For non-invasive measurements of cardiac output by electrical velocimetry, which is a variation of impedance cardiography, standard surface electrodes were applied to the left side of the neck and the left side of the thorax at the level of the xiphoid process. Cardiac output determined using direct Fick-oxygen principle was calculated by direct measurement of oxygen consumption (VO2) and invasive determination of the arterio-venous oxygen content difference. RESULTS: An excellent correlation (r=0.97) was found between CO(EV) and CO(F) (P<0.001). The slope of the regression equation [0.96 (SD 0.04)] was not significantly different from the line of identity. The bias between the two methods (CO(EV)-CO(F)) was 0.01 litre min(-1) and the limits of agreement, defined as the bias (2 SD), were -0.47 and +0.45 litre min(-1). CONCLUSIONS: CO(EV) demonstrates acceptable agreement with data derived from CO(F) in infants and children with congenital heart disease. The new technique is simple, completely non-invasive, and provides beat-to-beat estimation of CO.