Performance and composition of bacterial communities in anaerobic fluidized bed reactors for hydrogen production: Effects of organic loading rate and alkalinity

This study evaluated the effects of the organic loading rate (OLR) and pH buffer addition on hydrogen production in two anaerobic fluidized bed reactors (AFBRs) operated simultaneously. The AFBRs were fed with glucose, and expanded clay was used as support material. The reactors were operated at a temperature of 30 degrees C, without the addition of a buffer (AFBR1) and with the addition of a pH buffer (AFBR2, sodium bicarbonate) for OLRs ranging from 19.0 to 140.6 kg COD m(-3) d(-1) (COD: chemical oxygen demand). The maximum hydrogen yields for AFBR1 and AFBR2 were 2.45 and 1.90 mol H-2 mol(-1) glucose (OLR of 84.3 kg COD m(-3) d(-1)), respectively. The highest hydrogen production rates were 0.95 and 0.76 L h(-1) L-1 for AFBR1 and AFBR2 (OLR of 140.6 kg COD m(-3) d(-1)), respectively. The operating conditions in AFBR1 favored the presence of such bacteria as Clostridium, while the bacteria in AFBR2 included Clostridium, Enterobacter, Klebsiella, Veillonellaceae, Chryseobacterium, Sporolactobacillus, and Burkholderiaceae. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Retrospective Clinical Study of 988 Dual Acid-Etched Implants Placed in Grafted and Native Bone for Single-Tooth Replacement

Purpose: To evaluate the influence of sex, implant characteristics, and bone grafting on the survival rate of dual acid-etched (DAE) implants. Materials and Methods: Patients treated with internal-hex DAE implants for single-tooth replacement in a military dental clinic between January 2005 and December 2010 were included in this study. Clinical data related to implant characteristics, implant location, presence of grafted bone, and implant failures were collected. The primary outcome was implant loss. The survival rate was analyzed using the Kaplan-Meier method. Cox regression modeling was used to determine which factors would predict implant failure. Results: DAE implants were evaluated in a total of 988 patients (80.3% men). Twenty-four (2.4%) implants failed, most were cylindric (54.2%) with regular platforms (70.8%) and were 10 mm long (58.3%). The failure rate was 2.4% for the anterior maxilla, 3.3% for the posterior maxilla, 1.6% for the anterior mandible, and 2.0% for posterior mandible. The cumulative survival rate was 97.6%. The failure rate was 8.8% in implants placed after sinus augmentation, 7.3% in bone block-grafted areas, and 1.6% in native bone. Based on multivariable analysis (Cox regression), sinus augmentation and bone block grafting had a statistically significant effect on implant failure; the hazard ratios were 5.5 and 4.6, respectively. Conclusion: The results revealed that DAE implants had high survival rates, and no influence of sex, location, shape, diameter, or length on failure rates could be observed. However, a significant association was observed between failure and presence of bone graft in the implant area. Int J Oral Maxillofac Implants 2012;27:1243-1248

Sympathetic overactivity precedes metabolic dysfunction in a fructose model of glucose intolerance in mice

De Angelis K, Senador DD, Mostarda C, Irigoyen MC, Morris M. Sympathetic overactivity precedes metabolic dysfunction in a fructose model of glucose intolerance in mice. Am J Physiol Regul Integr Comp Physiol 302: R950-R957, 2012. First published February 8, 2012; doi: 10.1152/ajpregu.00450.2011.-Consumption of high levels of fructose in humans and animals leads to metabolic and cardiovascular dysfunction. There are questions as to the role of the autonomic changes in the time course of fructose-induced dysfunction. C57/BL male mice were given tap water or fructose water (100 g/l) to drink for up to 2 mo. Groups were control (C), 15-day fructose (F15), and 60-day fructose (F60). Light-dark patterns of arterial pressure (AP) and heart rate (HR), and their respective variabilities were measured. Plasma glucose, lipids, insulin, leptin, resistin, adiponectin, and glucose tolerance were quantified. Fructose increased systolic AP (SAP) at 15 and 60 days during both light (F15: 123 +/- 2 and F60: 118 +/- 2 mmHg) and dark periods (F15: 136 +/- 4 and F60: 136 +/- 5 mmHg) compared with controls (light: 111 +/- 2 and dark: 117 +/- 2 mmHg). SAP variance (VAR) and the low-frequency component (LF) were increased in F15 (>60% and >80%) and F60 (>170% and >140%) compared with C. Cardiac sympatho-vagal balance was enhanced, while baroreflex function was attenuated in fructose groups. Metabolic parameters were unchanged in F15. However, F60 showed significant increases in plasma glucose (26%), cholesterol (44%), triglycerides (22%), insulin (95%), and leptin (63%), as well as glucose intolerance. LF of SAP was positively correlated with SAP. Plasma leptin was correlated with triglycerides, insulin, and glucose tolerance. Results show that increased sympathetic modulation of vessels and heart preceded metabolic dysfunction in fructose-consuming mice. Data suggest that changes in autonomic modulation may be an initiating mechanism underlying the cluster of symptoms associated with cardiometabolic disease.

Dilute Acid Hydrolysis of Sugar Cane Bagasse at High Temperatures: A Kinetic Study of Cellulose Saccharification and Glucose Decomposition. Part I: Sulfuric Acid as the Catalyst

The kinetics of sugar cane bagasse cellulose saccharification and the decomposition of glucose under extremely low acid (ELA) conditions, (0.07%), 0.14%, and 0.28% H2SO4, and at high temperatures were investigated using batch reactors. The first-order rate constants were obtained by weight loss, remaining glucose, and fitting glucose concentration profiles determined with HPLC using the Saeman model. The maximum glucose yields reached 67.6% (200 degrees C, 0.07% H2SO4, 30 min), 69.8% (210 degrees C, 0.14% H2SO4, 10 min), and 67.3% (210 degrees C, 0.28% H2SO4, 6 min). ELA conditions produced remarkable glucose yields when applied to bagasse cellulose. The first-order rate constants were used to calculate activation energies and extrathermodynamic parameters to elucidate the reaction mechanism under ELA conditions. The effect of acid concentration on cellulose hydrolysis and glucose decomposition was also investigated. The observed activation energies and reaction orders with respect to hydronium ion for cellulose hydrolysis and glucose decomposition were 184.9 and 124.5 kJ/mol and 1.27 and 0.75, respectively.

17 beta-Estradiol replacement in young, adult and middle-aged female ovariectomized rats promotes improvement of spatial reference memory and an antidepressant effect and alters monoamines and BDNF levels in memory- and depression-related brain areas

Clinical and experimental evidence suggest that estrogens have a major impact on cognition, presenting neurotrophic and neuroprotective actions in regions involved in such function. In opposite, some studies indicate that certain hormone therapy regimens may provoke detrimental effects over female cognitive and neurological function. Therefore, we decided to investigate how estrogen treatment would influence cognition and depression in different ages. For that matter, this study assessed the effects of chronic 17 beta-estradiol treatment over cognition and depressive-like behaviors of young (3 months old), adult (7 months old) and middle-aged (12 months old) reproductive female Wistar rats. These functions were also correlated with alterations in the serotonergic system, as well as hippocampal BDNF. 17 beta-Estradiol treatment did not influence animals' locomotor activity and exploratory behavior, but it was able to improve the performance of adult and middle-aged rats in the Morris water maze, the latter being more responsive to the treatment. Young and adult rats displayed decreased immobility time in the forced swimming test, suggesting an effect of 17 beta-estradiol also over such depressive-like behavior. This same test revealed increased swimming behavior, triggered by serotonergic pathway, in adult rats. Neurochemical evaluations indicated that 17 beta-estradiol treatment was able to increase serotonin turnover rate in the hippocampus of adult rats. Interestingly, estrogen treatment increased BDNF levels from animals of all ages. These findings support the notion that the beneficial effects of 17 beta-estradiol over spatial reference memory and depressive-like behavior are evident only when hormone therapy occurs at early ages and early stages of hormonal decline. (C) 2011 Elsevier B.V. All rights reserved.

Performance of juveniles of Pseudoplatystoma fasciatum fed graded levels of corn gluten meal

The objective of this work was to evaluate corn gluten meal (CGM) as a substitute for fish meal in diets for striped catfish (Pseudoplatystoma fasciatum) juveniles. Eight isonitrogenous (46% crude protein) and isoenergetic (3,450 kcal kg(-1) digestible energy) diets, with increasing levels of CGM - 0, 6, 12, 18, 24, 30, 36, and 42%-, were fed to juvenile striped catfish (113.56 +/- 5.10 g) for seven weeks. Maximum values for weight gain, specific growth rate, protein efficiency ratio and feed conversion ratio, evaluated by polynomial quadratic regression, were observed with 10.4, 11.4, 15.4 and 15% of CGM inclusion, respectively. Feed intake decreased significantly from 0.8% CGM. Mesenteric fat index and body gross energy decreased linearly with increasing levels of CGM; minimum body protein contents were observed with 34.1% CGM. Yellow pigmentation of fillets significantly increased until 26.5% CGM, and decreased from this point forth. Both plasma glucose and protein concentrations decreased with increased CGM levels. The inclusion of 10-15% CGM promotes optimum of striped catfish juveniles depending on the parameter evaluated. Yellow coloration in fillets produced by CGM diets can have marketing implications.

Apoptosis rate and transcriptional response of pancreatic islets exposed to the PPAR gamma agonist Pioglitazone

To explore the molecular pathways underlying thiazolidinediones effects on pancreatic islets in conditions mimicking normo- and hyperglycemia, apoptosis rate and transcriptional response to Pioglitazone at both physiological and supraphysiological glucose concentrations were evaluated. Adult rat islets were cultured at physiological (5.6 mM) and supraphysiological (23 mM) glucose concentrations in presence of 10 μM Pioglitazone or vehicle. RNA expression profiling was evaluated with the PancChip 13k cDNA microarray after 24-h, and expression results for some selected genes were validated by qRT-PCR. The effects of Pioglitazone were investigated regarding apoptosis rate after 24-, 48- and 72-h. At 5.6 mM glucose, 101 genes were modulated by Pioglitazone, while 1,235 genes were affected at 23 mM glucose. Gene networks related to lipid metabolism were identified as altered by Pioglitazone at both glucose concentrations. At 23 mM glucose, cell cycle and cell death pathways were significantly regulated as well. At 5.6 mM glucose, Pioglitazone elicited a transient reduction in islets apoptosis rate while at 23 mM, Bcl2 expression was reduced and apoptosis rate was increased by Pioglitazone. Our data demonstrate that the effect of Pioglitazone on gene expression profile and apoptosis rate depends on the glucose concentration. The modulation of genes related to cell death and the increased apoptosis rate observed at supraphysiological glucose concentration raise concerns about Pioglitazone’s direct effects in conditions of hyperglycemia and reinforce the necessity of additional studies designed to evaluate TZDs effects on the preservation of β-cell function in situations where glucotoxicity might be more relevant than lipotoxicity.

Plasma kinetics of an LDL-like nanoemulsion and lipid transfer to HDL in subjects with glucose intolerance

OBJECTIVE: Glucose intolerance is frequently associated with an altered plasma lipid profile and increased cardiovascular disease risk. Nonetheless, lipid metabolism is scarcely studied in normolipidemic glucose-intolerant patients. The aim of this study was to investigate whether important lipid metabolic parameters, such as the kinetics of LDL free and esterified cholesterol and the transfer of lipids to HDL, are altered in glucose-intolerant patients with normal plasma lipids. METHODS: Fourteen glucose-intolerant patients and 15 control patients were studied; none of the patients had cardiovascular disease manifestations, and they were paired for age, sex, race and co-morbidities. A nanoemulsion resembling a LDL lipid composition (LDE) labeled with 14C-cholesteryl ester and ³H-free cholesterol was intravenously injected, and blood samples were collected over a 24-h period to determine the fractional clearance rate of the labels by compartmental analysis. The transfer of free and esterified cholesterol, triglycerides and phospholipids from the LDE to HDL was measured by the incubation of the LDE with plasma and radioactivity counting of the supernatant after chemical precipitation of non-HDL fractions. RESULTS: The levels of LDL, non-HDL and HDL cholesterol, triglycerides, apo A1 and apo B were equal in both groups. The 14C-esterified cholesterol fractional clearance rate was not different between glucose-intolerant and control patients, but the ³H-free-cholesterol fractional clearance rate was greater in glucose-intolerant patients than in control patients. The lipid transfer to HDL was equal in both groups. CONCLUSION: In these glucose-intolerant patients with normal plasma lipids, a faster removal of LDE free cholesterol was the only lipid metabolic alteration detected in our study. This finding suggests that the dissociation of free cholesterol from lipoprotein particles occurs in normolipidemic glucose intolerance and may participate in atherogenic signaling.

Primary stability in cementless total hip replacement: measurement techniques and aided-surgery

Primary stability of stems in cementless total hip replacements is recognized to play a critical role for long-term survival and thus for the success of the overall surgical procedure. In Literature, several studies addressed this important issue. Different approaches have been explored aiming to evaluate the extent of stability achieved during surgery. Some of these are in-vitro protocols while other tools are coinceived for the post-operative assessment of prosthesis migration relative to the host bone. In vitro protocols reported in the literature are not exportable to the operating room. Anyway most of them show a good overall accuracy. The RSA, EBRA and the radiographic analysis are currently used to check the healing process of the implanted femur at different follow-ups, evaluating implant migration, occurance of bone resorption or osteolysis at the interface. These methods are important for follow up and clinical study but do not assist the surgeon during implantation. At the time I started my Ph.D Study in Bioengineering, only one study had been undertaken to measure stability intra-operatively. No follow-up was presented to describe further results obtained with that device. In this scenario, it was believed that an instrument that could measure intra-operatively the stability achieved by an implanted stem would consistently improve the rate of success. This instrument should be accurate and should give to the surgeon during implantation a quick answer concerning the stability of the implanted stem. With this aim, an intra-operative device was designed, developed and validated. The device is meant to help the surgeon to decide how much to press-fit the implant. It is essentially made of a torsional load cell, able to measure the extent of torque applied by the surgeon to test primary stability, an angular sensor that measure the relative angular displacement between stem and femur, a rigid connector that enable connecting the device to the stem, and all the electronics for signals conditioning. The device was successfully validated in-vitro, showing a good overall accuracy in discriminating stable from unstable implants. Repeatability tests showed that the device was reliable. A calibration procedure was then performed in order to convert the angular readout into a linear displacement measurement, which is an information clinically relevant and simple to read in real-time by the surgeon. The second study reported in my thesis, concerns the evaluation of the possibility to have predictive information regarding the primary stability of a cementless stem, by measuring the micromotion of the last rasp used by the surgeon to prepare the femoral canal. This information would be really useful to the surgeon, who could check prior to the implantation process if the planned stem size can achieve a sufficient degree of primary stability, under optimal press fitting conditions. An intra-operative tool was developed to this aim. It was derived from a previously validated device, which was adapted for the specific purpose. The device is able to measure the relative micromotion between the femur and the rasp, when a torsional load is applied. An in-vitro protocol was developed and validated on both composite and cadaveric specimens. High correlation was observed between one of the parameters extracted form the acquisitions made on the rasp and the stability of the corresponding stem, when optimally press-fitted by the surgeon. After tuning in-vitro the protocol as in a closed loop, verification was made on two hip patients, confirming the results obtained in-vitro and highlighting the independence of the rasp indicator from the bone quality, anatomy and preserving conditions of the tested specimens, and from the sharpening of the rasp blades. The third study is related to an approach that have been recently explored in the orthopaedic community, but that was already in use in other scientific fields. It is based on the vibration analysis technique. This method has been successfully used to investigate the mechanical properties of the bone and its application to evaluate the extent of fixation of dental implants has been explored, even if its validity in this field is still under discussion. Several studies have been published recently on the stability assessment of hip implants by vibration analysis. The aim of the reported study was to develop and validate a prototype device based on the vibration analysis technique to measure intra-operatively the extent of implant stability. The expected advantages of a vibration-based device are easier clinical use, smaller dimensions and minor overall cost with respect to other devices based on direct micromotion measurement. The prototype developed consists of a piezoelectric exciter connected to the stem and an accelerometer attached to the femur. Preliminary tests were performed on four composite femurs implanted with a conventional stem. The results showed that the input signal was repeatable and the output could be recorded accurately. The fourth study concerns the application of the device based on the vibration analysis technique to several cases, considering both composite and cadaveric specimens. Different degrees of bone quality were tested, as well as different femur anatomies and several levels of press-fitting were considered. The aim of the study was to verify if it is possible to discriminate between stable and quasi-stable implants, because this is the most challenging detection for the surgeon in the operation room. Moreover, it was possible to validate the measurement protocol by comparing the results of the acquisitions made with the vibration-based tool to two reference measurements made by means of a validated technique, and a validated device. The results highlighted that the most sensitive parameter to stability is the shift in resonance frequency of the stem-bone system, showing high correlation with residual micromotion on all the tested specimens. Thus, it seems possible to discriminate between many levels of stability, from the grossly loosened implant, through the quasi-stable implants, to the definitely stable one. Finally, an additional study was performed on a different type of hip prosthesis, which has recently gained great interest thus becoming fairly popular in some countries in the last few years: the hip resurfacing prosthesis. The study was motivated by the following rationale: although bone-prosthesis micromotion is known to influence the stability of total hip replacement, its effect on the outcome of resurfacing implants has not been investigated in-vitro yet, but only clinically. Thus the work was aimed at verifying if it was possible to apply to the resurfacing prosthesis one of the intraoperative devices just validated for the measurement of the micromotion in the resurfacing implants. To do that, a preliminary study was performed in order to evaluate the extent of migration and the typical elastic movement for an epiphyseal prosthesis. An in-vitro procedure was developed to measure micromotions of resurfacing implants. This included a set of in-vitro loading scenarios that covers the range of directions covered by hip resultant forces in the most typical motor-tasks. The applicability of the protocol was assessed on two different commercial designs and on different head sizes. The repeatability and reproducibility were excellent (comparable to the best previously published protocols for standard cemented hip stems). Results showed that the procedure is accurate enough to detect micromotions of the order of few microns. The protocol proposed was thus completely validated. The results of the study demonstrated that the application of an intra-operative device to the resurfacing implants is not necessary, as the typical micromovement associated to this type of prosthesis could be considered negligible and thus not critical for the stabilization process. Concluding, four intra-operative tools have been developed and fully validated during these three years of research activity. The use in the clinical setting was tested for one of the devices, which could be used right now by the surgeon to evaluate the degree of stability achieved through the press-fitting procedure. The tool adapted to be used on the rasp was a good predictor of the stability of the stem. Thus it could be useful for the surgeon while checking if the pre-operative planning was correct. The device based on the vibration technique showed great accuracy, small dimensions, and thus has a great potential to become an instrument appreciated by the surgeon. It still need a clinical evaluation, and must be industrialized as well. The in-vitro tool worked very well, and can be applied for assessing resurfacing implants pre-clinically.

Bedeutung von allelen Varianten des Hexose-Transporters Hxt3p und der Hexokinasen Hxk1p und Hxk2p für Aufnahme und Verwertung von Glucose und Fructose durch Weinhefen

In Hinsicht darauf, dass sich S. cerevisiae-Stämme im Laufe der Domestizierung und Anpassung an verschiedene Habitate genetisch verändert haben, wurde in dieser Arbeit eine repräsentative Auswahl von Labor-, kommerziellen und in der Natur vorkommenden Saccharomyces-Stämmen und ihren Interspezies-Hybriden auf die Verbreitung alleler Varianten der Hexokinase-Gene HXK1 und HXK2 getestet. Von den Hexose-Transportern stand Hxt3p im Mittelpunkt, da seine essentielle Rolle bei der Vergärung von Glucose und Fructose bereits belegt wurde.rnIn dieser Arbeit wurde gezeigt, dass es bedeutende Unterschiede in der Vergärung von Glucose und Fructose zwischen Weinhefen der Gattung Saccharomyces gibt, die z.T. mit Struktur-Varianten des Hexose-Transporter Hxt3p korrelieren. rnInsgesamt 51 Hefestämme wurden auf ihre allele Variante des HXT3-Gens untersucht. Dabei haben sich drei Hauptgruppen (die Fermichamp®-Typ Gruppe, Bierhefen und Hybrid-Stämme) mit unterschiedlichem HXT3-Allel ergeben. Im Zusammenhang mit der Weinherstellung wurden signifikante Nukleotid-Substitutionen innerhalb des HXT3-Gens der robusten S. cerevisiae-Stämme (wie z.B. Sekthefen, kommerzielle Starterkulturen) und Hybrid-Stämmen festgestellt. Diese Hefen zeichneten sich durch die Fähigkeit aus, den Most trotz stressigen Umwelt-Bedingungen (wie hohe Ethanol-Konzentration, reduzierter Ammonium-Gehalt, ungünstiges Glucose:Fructose-Verhältnis) zu vergären. rnDie Experimente deuten darauf hin, dass die HXT3-Allel-Variante des als Starterkultur verwendbaren Stammes Fermichamp®, für den verstärkten Fructose-Abbau verantwortlich ist. Ein gleiches Verhalten der Stämme mit dieser Allel-Variante wurde ebenfalls beobachtet. Getestet wurden die S. cerevisiae-Stämme Fermichamp® und 54.41, die bezüglich Hxt3p-Aminosäuresequenz gleich sind, gegenüber zwei S. cerevisiae-Stämmen mit dem HXT3-Standard-Alleltyp Fermivin® und 33. Der Unterschied in der Hexose-Verwertung zwischen Stämmen mit Fermichamp®- und Standard-Alleltyp war in der Mitte des Gärverlaufs am deutlichsten zu beobachten. Beide Gruppen, sowohl mit HXT3 Fermichamp®- als auch Fermivin®-Alleltyp vergoren die Glucose schneller als die Fructose. Der Unterschied aber zwischen diesen HXT3-Alleltypen bei der Zucker-Verwertung lag darin, dass der Fermichamp®-Typ eine kleinere Differenz in der Abbau-Geschwindigkeit der beiden Hexosen zeigte als der Fermivin®-Typ. Die Zuckeraufnahme-Messungen haben die relativ gute Fructose-Aufnahme dieser Stämme bestätigt.rnEbenfalls korrelierte der fructophile Charakter des Triple-Hybrides S. cerevisiae x S. kudriavzevii x S. bayanus-Stamm HL78 in Transportexperimenten mit verstärkter Aufnahme von Fructose im Vergleich zu Glucose. Insgesamt zeigte dieser Stamm ähnliches Verhalten wie die S. cerevisiae-Stämme Fermichamp® und 54.41. rnIn dieser Arbeit wurde ein Struktur-Modell des Hexose-Transporters Hxt3p erstellt. Als Basis diente die zu 30 % homologe Struktur des Proton/Xylose-Symporters XylE aus Escherichia coli. Anhand des Hxt3p-Modells konnten Sequenzbereiche mit hoher Variabilität (Hotspots) in drei Hxt3p-Isoformen der Hauptgruppen (die Fermichamp®-Typ Gruppe, Bierhefen und Hybrid-Stämme) detektiert werden. Diese signifikanten Aminosäure-Substitutionen, die eine mögliche Veränderung der physikalischen und chemischen Eigenschaften des Carriers mit sich bringen, konzentrieren sich auf drei Bereiche. Dazu gehören die Region zwischen den N- und C-terminalen Domänen, die cytosolische Domäne und der Outside-Loop zwischen Transmembranregion 9 und Transmembranregion 10. rnObwohl die Transportmessungen keinen Zusammenhang zwischen Stämmen mit unterschiedlichen HXT3-Allelen und ihrer Toleranz gegenüber Ethanol ergaben, wurde ein signifikanter Anstieg in der Zuckeraufnahme nach vorheriger 24-stündiger Inkubation mit 4 Vol% Ethanol bei den Teststämmen beobachtet. rnInsgesamt könnten allele Varianten von HXT3-Gen ein nützliches Kriterium bei der Suche nach robusten Hefen für die Weinherstellung oder für andere industrielle Anwendungen sein. Die Auswirkung dieser Modifikationen auf die Struktur und Effizienz des Hexose-Transporters, sowie der mögliche Zusammenhang mit Ethanol-Resistenz müssen weiter ausführlich untersucht werden. rnEin Zusammenhang zwischen den niedrig variablen Allel-Varianten der Hexokinase-Gene HXK1 und HXK2 und dem Zucker-Metabolismus wurde nicht gefunden. Die Hexokinasen der untersuchten Stämme wiesen allerdings generell eine signifikante geringere Affinität zu Fructose im Vergleich zu Glucose auf. Hier liegt sicherlich eine Hauptursache für den Anstieg des Fructose:Glucose-Verhältnisses im Laufe der Vergärung von Traubenmosten.rn

Simultaneous bilateral hip replacement reveals superior outcome and fewer complications than two-stage procedures: a prospective study including 1819 patients and 5801 follow-ups from a total joint replacement registry

Background Total joint replacements represent a considerable part of day-to-day orthopaedic routine and a substantial proportion of patients undergoing unilateral total hip arthroplasty require a contralateral treatment after the first operation. This report compares complications and functional outcome of simultaneous versus early and delayed two-stage bilateral THA over a five-year follow-up period. Methods The study is a post hoc analysis of prospectively collected data in the framework of the European IDES hip registry. The database query resulted in 1819 patients with 5801 follow-ups treated with bilateral THA between 1965 and 2002. According to the timing of the two operations the sample was divided into three groups: I) 247 patients with simultaneous bilateral THA, II) 737 patients with two-stage bilateral THA within six months, III) 835 patients with two-stage bilateral THA between six months and five years. Results Whereas postoperative hip pain and flexion did not differ between the groups, the best walking capacity was observed in group I and the worst in group III. The rate of intraoperative complications in the first group was comparable to that of the second. The frequency of postoperative local and systemic complication in group I was the lowest of the three groups. The highest rate of complications was observed in group III. Conclusions From the point of view of possible intra- and postoperative complications, one-stage bilateral THA is equally safe or safer than two-stage interventions. Additionally, from an outcome perspective the one-stage procedure can be considered to be advantageous.

Percutaneous aortic valve replacement: valvuloplasty studies in vitro

Valvuloplasty of the aortic valve is currently used in selected patients for severe calcified aortic valve disease, but clinical effectiveness is low and complication rate remains high. In this study, the total particle load after valvuloplasty and the embolization risk of calcific debris into the coronary arteries was analyzed in an in vitro model.

REGULATION OF WHOLE-BODY ENERGY HOMEOSTASIS WITH GROWTH HORMONE REPLACEMENT THERAPY AND ENDURANCE EXERCISE

We hypothesized that network analysis is useful to expose coordination between whole body and myocellular levels of energy metabolism and can identify entities that underlie skeletal muscle's contribution to growth hormone-stimulated lipid handling and metabolic fitness. We assessed 112 metabolic parameters characterizing metabolic rate and substrate handling in tibialis anterior muscle and vascular compartment at rest, after a meal and exercise with growth hormone replacement therapy (GH-RT) of hypopituitary patients (n = 11). The topology of linear relationships (| r | ≥ 0.7, P ≤ 0.01) and mutual dependencies exposed the organization of metabolic relationships in three entities reflecting basal and exercise-induced metabolic rate, triglyceride handling, and substrate utilization in the pre- and postprandial state, respectively. GH-RT improved aerobic performance (+5%), lean-to-fat mass (+19%), and muscle area of tibialis anterior (+2%) but did not alter its mitochondrial and capillary content. Concomitantly, connectivity was established between myocellular parameters of mitochondrial lipid metabolism and meal-induced triglyceride handling in serum. This was mediated via the recruitment of transcripts of muscle lipid mobilization (LIPE, FABP3, and FABP4) and fatty acid-sensitive transcription factors (PPARA, PPARG) to the metabolic network. The interdependence of gene regulatory elements of muscle lipid metabolism reflected the norm in healthy subjects (n = 12) and distinguished the regulation of the mitochondrial respiration factor COX1 by GH and endurance exercise. Our observations validate the use of network analysis for systems medicine and highlight the notion that an improved stochiometry between muscle and whole body lipid metabolism, rather than alterations of single bottlenecks, contributes to GH-driven elevations in metabolic fitness.

International survey of primary and revision total knee replacement

Purpose Total knee arthroplasty (TKA) is currently the international standard of care for treating degenerative and rheumatologic knee joint disease, as well as certain knee joint fractures. We sought to answer the following three research questions: (1) What is the international variance in primary and revision TKA rates around the world? (2) How do patient demographics (e.g., age, gender) vary internationally? (3) How have the rates of TKA utilization changed over time? Methods The survey included 18 countries with a total population of 755 million, and an estimated 1,324,000 annual primary and revision total knee procedures. Ten national inpatient databases were queried for this study from Canada, the United States, Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, and Switzerland. Inpatient data were also compared with published registry data for eight countries with operating arthroplasty registers (Denmark, England & Wales, Norway, Romania, Scotland, Sweden, Australia, and New Zealand). Results The average and median rate of primary and revision (combined) total knee replacement was 175 and 149 procedures/100,000 population, respectively, and ranged between 8.8 and 234 procedures/100,000 population. We observed that the procedure rate significantly increased over time for the countries in which historical data were available. The compound annual growth in the incidence of TKA ranged by country from 5.3% (France) to 17% (Portugal). We observed a nearly 27-fold range of TKA utilization rates between the 18 different countries included in the survey. Conclusion It is apparent from the results of this study that the demand for TKA has risen substantially over the past decade in countries around the world.

Recent developments for surgical aortic valve replacement: the concept of sutureless valve technology

Aortic stenosis has become the most frequent type of valvular heart disease in Europe and North America and presents in the large majority of patients as calcified aortic stenosis in adults of advanced age. Surgical aortic valve replacement has been recognized to be the definitive therapy which improves considerably survival for severe aortic stenosis since more than 40 years. In the most recent period, operative mortality of isolated aortic valve replacement for aortic stenosis varies between 1–3% in low-risk patients younger than 70 years and between 4 and 8% in selected older adults. Long-term survival following aortic valve replacement is close to that observed in a control population of similar age. Numerous observational studies have consistently demonstrated that corrective surgery in symptomatic patients is invariably followed by a subjective improvement in quality of life and a substantial increase in survival rates. More recently, transcatheter aortic valve implantation (TAVI) has been demonstrated to be feasible in patients with high surgical risk using either a retrograde transfemoral or transsubclavian approach or an antegrade, transapical access. Reported 30-day mortality ranges between 5 and 15%) and is acceptable when compared to the risk predicted by the logistic EuroSCORE (varying between 20 and 35%) and the STS Score, although the EuroScore has been shown to markedly overestimate the effective operative risk. One major concern remains the high rate of paravalvular regurgitation which is observed in up to 85% of the patients and which requires further follow-up and critical evaluation. In addition, long-term durability of these valves with a focus on the effects of crimping remains to be addressed, although 3-5 year results are promising. Sutureless biological valves were designed to simplify and significantly accelerate the surgical replacement of a diseased valve and allow complete excision of the calcified native valve. Until now, there are 3 different sutureless prostheses that have been approved. The 3f Enable valve from ATS-Medtronic received CE market approval in 2010, the Perceval S from Sorin during Q1 of 2011 and the intuity sutureless prosthesis from Edwards in 2012. All these devices aim to facilitate valve surgery and therefore have the potential to decrease the invasivness and to shorten the conventional procedure without compromise in term of excision of the diseased valve. This review summarizes the history and the current knowledge of sutureless valve technology.