A distinctive release profile of vancomycin and tobramycin from a new and injectable polymeric dicalcium phosphate dehydrate cement (P-DCPD).

A novel injectable polymeric dicalcium phosphate dehydrate (P-DCPD) cement was developed with superior mechanical strength and excellent cohesion. The purpose of this study was to assess the in vitro performance of P-DCPD loaded with vancomycin (VAN-P), tobramycin (TOB-P) and combination of both (VAN/TOB-P) (10%, w/w). There is a distinctive release profile between VAN and TOB. VAN-P showed decreased initial burst (<30% within 3 d) and sustained VAN release (76% in 28 d). In the presence of TOB (VAN/TOB-P), >90% of VAN was released within 3 d (p < 0.05). Slow and limited TOB release was observed both in TOB-P (<5%) and in TOB/VAN-P (<1%) over 28 d. Zone of inhibition (ZOI) of Staphylococcus aureus growth showed that eluents collected from VAN-P had stronger and longer ZOI (28 d) than that from TOB-P (14 d, p < 0.05). Direct contact of VAN-P, TOB-P and VAN/TOB-P cements displayed persistent and strong ZOI for >3 weeks. Interestingly, the cement residues (28 d after drug release) still maintained strong ZOI ability. P-DCPD with or without antibiotics loading were nontoxic and had no inferior impacts on the growth of osteoblastic MC3T3 cells. VAN-P and TOB-P were injectable. No significant influence on setting time was observed in both VAN-P (11.7 ± 1.9 min) and VAN/TOB-P (10.8 ± 1.5 min) as compared to control (12.2 ± 2.6 min). We propose that a distinctive release profile of VAN and TOB observed is mainly due to different distribution pattern of VAN and TOB within P-DCPD matrix. A limited release of TOB might be due to the incorporation of TOB inside the crystalline lattice of P-DCPD crystals. Our data supported that the bactericidal efficacy of antibiotics-loaded P-DCPD is not only depend on the amount and velocity of antibiotics released, but also probably more on the direct contact of attached bacteria on the degrading cement surface.

Therapeutic drug monitoring is useful when pharmacogenetic assessment is unavailable: case report of delusional disorder / La monitorización terapéutica de fármacos es útil cuando la evaluación farmacogenética no está disponible: caso clínico de trastorno delirante

Antipsychotic plasma levels have been extensively used in the assessment of poor treatment response, lack of adherence and adverse events in delusional disorder. It has not been used as an indicator of metabolizer status, to determine whether a delusional disorder patient is a poor, intermediate, or ultra-rapid metabolizer of antipsychotics. Pharmacogenetic probes are, of course, the right method for the latter task, but they are not readily available for clinical use. We report the case of a 46-year-old woman with delusional disorder who developed unexpected adverse effects to treatment with relatively low dose risperidone and poor symptomatic response. Blood level monitoring indicated high levels of risperidone and a high concentration-to-dose ratio, which suggested accumulation of unmetabolized risperidone. Paradoxically, extrapyramidal side effects increased when, after reducing the risperidone dose, 5 mg/day of aripiprazole was added. Consequently, the patient was switched to olanzapine 5 mg/day. Sertraline 150 mg/day was later added for comorbid depression. A complete symptomatic response was achieved. Although other factors may well have been at play, this sequence of events suggests that the patient was a slow metabolizer of CYP2D6, which metabolizes both risperidone and aripiprazole. With pharmacogenetic assessment not available, therapeutic drug monitoring helped clinicians decide on appropriate management

Los niveles plasmáticos de antipsicóticos han sido extensamente utilizados para la evaluación de la pobre respuesta terapéutica, la falta de adherencia y los eventos adversos en pacientes con trastorno delirante. No han sido frecuentemente utilizados como indicadores del estado metabólico, para determinar si un paciente con trastorno delirante es metabolizador pobre, intermedio o metabolizador ultra-rápido de antipsicóticos. Los test de farmacogenética son, por supuesto, el método más idóneo para la última tarea, pero no son fáciles de obtener para su uso clínico. Reportamos el caso de una mujer de 46 años de edad con trastorno delirante que ha desarrollado efectos adversos inesperados con el tratamiento a dosis bajas de risperidona, y una pobre respuesta clínica. La monitorización de niveles plasmáticos indicó niveles elevados de risperidona y una ratio elevada concentración-dosis, que sugirió acumulación de risperidona no adecuadamente metabolizada. Paradójicamente, los efectos secundarios se incrementaron, cuando al reducir la dosis de risperidona, se añadió aripiprazol 5mg/día. Por ello, se realizó un cambio a olanzapina 5 mg/día. Se añadió sertralina 150 mg/día posteriormente para el tratamiento de síntomas depresivos comórbidos. Se alcanzó una respuesta clínica completa. A pesar de que otros factores pudieran haber contribuido a ello, la secuencia de eventos sugiere que la paciente pudiera ser metabolizadora lenta del CYP2D6, que metaboliza risperidona y aripiprazol. En caso de no disponibilidad de tests farmacogenéticos, la monitorización de niveles plasmáticos, ayudó a los clínicos a decidir el manejo apropiado del paciente

The link between the microbial ecology, gene expression, and biokinetics of denitrifying polyphosphate-accumulating systems under different electron acceptor combinations.

The emission of the greenhouse gas nitrous oxide (N2O) can occur during biological nutrient removal. Denitrifying enhanced biological phosphorus removal (d-EBPR) systems are an efficient means of removing phosphate and nitrogen, performed by denitrifying polyphosphate-accumulating organisms (d-PAOs). The aim of this work was to study the effect of various combinations of electron acceptors, nitrate (NO3-), nitrite (NO2-), and N2O, on the denitrification pathway of a d-EBPR system. Batch tests were performed with different electron acceptor combinations, to explore the denitrification pathway. Reverse transcriptase-qPCR (RT-qPCR) and high-throughput sequencing, combined with chemical analysis, were used to study gene expression, microbial diversity, and denitrification kinetics. The potential for N2O production was greater than the potential for its reduction in most tests. A strong correlation was observed between the N2O reduction rate and the relative gene expression of nitrous oxide reductase per nitrite reductase (nosZ/(nirS + nirK)), suggesting that the expression of denitrifying marker genes is a strong predictor of the N2O reduction rate. The d-EBPR community maintained a core population with low variations throughout the study. Furthermore, phylogenetic analyses of the studied marker genes revealed that the organisms actively involved in denitrification were closely related to Thauera sp., Candidatus Accumulibacter phosphatis, and Candidatus Competibacter denitrificans. Moreover, Competibacter-related OTUs seem to be important contributors to the N2O reduction capacity of the system, likely scavenging the N2O produced by other organisms. Overall, this study contributes to a better understanding of the microbial biochemistry and the genetics involving biological denitrification removal, important to minimize N2O emissions in wastewater treatment plants.

Nivel de riesgo y aparición de úlceras por presión en pacientes en estado crítico / Risk level and pressure ulcer in patients in critical status / Nível de risco e aparição de úlceras por pressão em pacientes em estado crítico

La úlcera por presión es un evento constante en salud pública, un problema persistente en las unidades críticas y una preocupación de enfermería al verse involucrada en el cuidado que demanda el 50% más del tiempo utilizado. Objetivo: Describir el riesgo de aparición de las úlceras por presión en los pacientes ingresados en la unidad de cuidados críticos, con relación al tiempo de medición y estadio. Métodos: Estudio cuantitativo, observacional, descriptivo y longitudinal. Muestra: conformada por 31 pacientes. El instrumento fue aplicado en 4 momentos: Al ingreso, a las 24 y 72 h y al séptimo día de estancia. En cada medición se determinó el riesgo con la escala Braden y se valoró la piel. Resultado: El 100% de los pacientes tuvo alto riesgo al ingreso y 24 h; se redujo en un 71% a los 7 días. El 6.4% desarrolló úlcera por presión al ingreso, el 12.9% a las 24 h y el 35.5% a las 72 h. En general el 45.2% de los pacientes considerados como de alto riesgo manifestaron úlcera por presión a los 7 días de estancia hospitalaria. Se observó una correlación entre las variables nivel de riesgo y aparición de úlcera por presión a las 72 h (rs p = 0.04). Conclusión: A pesar de que se reduce el riesgo a la mitad en las primeras 72 h, aumenta la incidencia de úlcera por presión en ese mismo lapso; así, es importante que se realicen evaluaciones y revaloraciones desde el ingreso y durante los 7 primeros días de estancia hospitalaria en los pacientes críticamente enfermos utilizando un instrumento de valor predictivo.

Pressure ulcer are a constant event in public health, a persistent problem in units of critical care, and a nursing concern due to the longtime of care they need to be addressed. Objective To describe the risk of developing pressure ulcer which patients admitted into the critical care taking in consideration the time of measurement and stay. Methods This is a quantitative, observational, descriptive, and longitudinal study with a sample of 31 patients. The instrument was administered at four times: At entry, during the 24 and 72 hours, and at the seventh day of stay. In each measurement, the risk was assessed through the Braden scale. The skin status was also assessed. Result: 100% of patients were at high risk during the first 24 hours; and 71% of them were at high risk at the seventh day of admission. 6.4% developed a pressure ulcer during admission, 12.9% at 24 hours, and 35.5% at 72 hours. In general, 45.2% of the patients considered in high risk developed some pressure ulcer at the seventh day of stay. A correlation was observed among the variables risk level and pressure sores at 72 hours (rs P = .04>). Conclusion: Although the risk is reduced to the half during the first 72 hours, the incidence of pressure ulcer increases in the same period; thus, it is important to perform assessments and re-appraisements to the critically ill patients using a predictive instrument since hospital admission and during the first seven days of stay.

A úlcera por pressão é um evento constante em saúde pública, um problema persistente nas unidades críticas e uma preocupação de enfermagem ao ser envolvida no cuidado que demanda 50% mais do tempo utilizado. Objetivo: Descrever o risco de aparição das úlceras por pressão nos pacientes internados na unidade de cuidados críticos, em relação ao tempo de medição e estádio. Métodos: Estudo quantitativo, observacional, descritivo e longitudinal. Amostra conformada por 31 pacientes. O instrumento foi aplicado em quatro momentos: à entrada, às 24 e 72 horas e ao sétimo dia da permanência. Em cada medição determinou-se o risco com a escala Braden e avaliou-se a pele. Resultado: 100% dos pacientes teve alto risco à entrada e 24 horas; diminuiu em um 71% aos sete dias. 6.4% desenvolveu úlcera por pressão à entrada, 12.9% às 24 horas e 35.5% às 72 horas. Em geral 45.2% dos pacientes considerados como de alto risco manifestaram úlcera por pressão aos sete dias de permanência hospitalar. Observou-se uma correlação entre as variáveis nível de risco e aparição de úlcera por pressão às 72 horas (rs = 0.04>). Conclusão: Apesar de que se reduz o risco à metade nas primeiras 72 horas, aumenta a incidência de úlcera por pressão no mesmo período, assim, é importante que se realizem avaliações e reavaliações desde a entrada e durante os sete primeiros dias de permanência nos pacientes criticamente doentes, utilizando um instrumento de valor preditivo.

Impact of the addition of a nitrifying activated sludge on ammonia oxidation during composting of residual household wastes.

AIMS: To investigate the nitrogen-microbial community dynamics during composting of a mixture of nitrifying waste activated sludge (WAS) and fine organic fraction of residual household waste (RHW). To examine whether the addition of nitrifying sludge could promote ammonia oxidation and reduce ammonia emissions. METHODS AND RESULTS: The fine organic fraction of RHW was mixed with the WAS and homogenized. The mixture and each waste alone were loaded in aerobic cells under controlled conditions, respectively. Both nitrogen and microbial community dynamics were monitored during 50 days of composting. The ammonia oxidizers were quantified and identified in the sludge and compost. The changes in ammonia-oxidizing bacteria (AOB) concentrations corresponded to the ammonia oxidation rates calculated from nitrogen balance. The addition of WAS did not efficiently reduce ammonia emissions because the Nitrosomonas oligotropha-like AOB introduced declined during the active stage of composting. Ammonia oxidation was probably limited by the intense heterotrophic activities at the active stage. Nitrosomonas europaea/eutropha and Nitrosomonas nitrosa-like AOB were established only during the maturation stage. They were the main contributors to ammonia oxidation during composting. CONCLUSIONS: The mixing of nitrifying WAS with the RHW during the early stages of composting does not promote ammonia oxidation nor reduce ammonia emissions because of limiting biologic factors during the active stage of composting. SIGNIFICANCE AND IMPACT OF THE STUDY: The mixing of activated sludge with RHW before composting is a common practice on composting plants. This study proved the limitation of this practice to reduce ammonia emissions during composting via bioaugmentation of ammonia-oxidizing organisms. It correlated successfully the ammonia oxidation rate with different groups of ammonia oxidizers and explains the fail of promoting ammonia oxidation during the early stages of composting. It suggests Nit. europaea/eutropha and Nit. nitrosa-like AOB were the main contributors to ammonia oxidation during composting.

Rhabdomyolysis as a clinical manifestation of association with ciprofibrate, sirolimus, cyclosporine, and pegylated interferon-α in liver-transplanted patients: a case report and literature review.

BACKGROUND: Rhabdomyolysis is a syndrome characterized by impaired metabolic integrity of myocytes, causing the release of intracellular constituents into the circulation, and can be a serious side effect of drug intake. CASE REPORT: This report describes a unique case of rabdomyolysis secondary in which ciprofibrate, sirolimus, cyclosporine, and pegylated interferon-α in a liver transplant patient was used. A 47-year-old male liver transplant recipient in 2009, who had hepatitis C and incidental hepatocellular carcinoma, underwent immunosuppressive therapy (cyclosporine and sirolimus). The patient is currently in treatment for viral recurrence with pegylated interferon-α and ribavirin; he had a history of hypertriglyceridemia treated with ciprofibrate. He had development of severe and generalized myalgia and fever after the eighth application of pegylated interferon-α and increasing doses of cyclosporine. Laboratorial tests showed acute renal failure and significant increase in creatine kinase. Rhabdomyolysis secondary to interaction of fibrate-cyclosporine-pegylated interferon-α was postulated. CONCLUSIONS: Medical professionals should be aware of possible drug interactions and should monitor patients receiving these drugs.

Odorous gaseous emissions as influence by process condition for the forced aeration composting of pig slaughterhouse sludge.

Compost sustainability requires a better control of its gaseous emissions responsible for several impacts including odours. Indeed, composting odours have stopped the operation of many platforms and prevented the installation of others. Accordingly, present technologies collecting and treating gases emitted from composting are not satisfactory and alternative solutions must be found. Thus, the aim of this paper was to study the influence of composting process conditions on gaseous emissions. Pig slaughterhouse sludge mixed with wood chips was composted under forced aerationin 300 L laboratory reactors. The process conditions studied were: aeration rate of 1.68, 4.03, 6.22, 9.80 and 13.44 L/h/kg of wet sludge; incorporation ratio of 0.55, 0.83 and 1.1 (kg of wet wood chips/kg of wet sludge), and; bulking agent particles size of <10, 10<20 and 20<30 mm. Out-going gases were sampled every 2 days and their composition was analysed using gas chromatography coupled with mass spectrometry (GC-MS). Fifty-nine compounds were identified and quantified. Dividing the cumulated mass production over 30 days of composting, by odour threshold, 9 compounds were identified as main potential odour contributors: hydrogen sulphide, trimethylamine, ammonia, 2-pentanone, 1-propanol-2-methyl, dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide and acetophenone. Five gaseous compounds were correlated with both aeration rate and bulking agent to waste ratio: hydrogen sulphide, trimethylamine, ammonia, 2-pentanone and 1-propanol-2-methyl. However, dropping the aeration rate and increasing the bulking agent to waste ratio reduced gaseous odour emissions by a factor of 5-10, when the required threshold dilution factor ranged from 10(5) to 10(6), to avoid nuisance at peak emission rates. Process influence on emissions of dimethyl sulphide, dimethyl disulphide, dimethyl trisulphide were poorly correlated with both aeration rate and bulking agent to waste ratio as a reaction with hydrogen sulphide was suspected. Acetophenone emissions originated from the wood chips. Olfactory measurements need to be correlated to gaseous emissions for a more accurate odour emission evaluation.

HHV-6: clinical and laboratory investigations and correlations with encephalitis in liver transplant recipients.

OBJECTIVE: Human herpesvirus (HHV) 6 infections and reactivation are emerging factors in neurology. This study aimed to verify the presence of encephalitis associated with HHV-6 positivity by antigenemia or polymerase chain reaction (PCR) in liver transplant recipients. METHODS: We analyzed the medical records and laboratory results of 20 recipients with antigenemia or a positive PCR for HHV-6. The range of the transplantation dates was September 2006 to March 2010; the period of the medical records was from the date of transplantation to 1 year thereafter. Encephalitis was diagnosed by these symptoms: fever, mening, signs, seizures, dysphasia, visual and hearing impairment, or sensory and motion alterations. "Possible encephalitis" was considered when the patients had at least 2 of the symptoms. PCR or antigenemia for HHV-6 was not performed with central nervous fluid. The correlation between HHV-6 infection and encephalitis was evaluated with the use of descriptive statistical tests. RESULTS: Symptoms associated with encephalitis occurred in 7/20, patients (35%): 5/20 with fever and 4/20 with mental confusion. Involuntary movements were present in 1 case. The symptoms appeared with in the first 10 days in 6/20 patients and lasted for 1 year. CONCLUSIONS: This study showed that symptoms associated with encephalitis occurred in a considerable number of patients with positive PCR and/or antigenemia for HHV-6 after liver transplantation. This correlation needs retrospectie and prospective studies to determine the specific association.

Correlation between serum magnesium levels and hepatic encephalopathy in immediate post liver transplantation period.

UNLABELLED: Liver transplantation is a complex procedure that interferes with multiple body functions and can cause several complications. Studies have shown varying incidences of neurological complications (8% to 47%) including encephalopathy, as well as cerebrovascular problems, infections, and neurotoxicity induced by immunosuppressive drugs. The majority of these cases occur in the first week after surgery. OBJECTIVE: We sought to evaluate the correlation between serum magnesium levels and the development of encephalopathy in the immediate posttransplantation period. METHODS: We collected data from patients undergoing liver transplantation, both donors and recipients, from 2007 to 2009. Magnesium levels during the first week of hospitalization were compared to reference laboratory results. The West Haven criteria were used to classify whether if the patient experienced encephalopathy. RESULTS: Only the level of magnesium posttransplantation represented a risk for encephalopathy (P = .049). Lower magnesium levels increased the risk of encephalopathy (relative risk = 3.718; 95% confidence interval: 1.001-13.699). CONCLUSION: We verified the importance of low levels of magnesium as a predictive factor to increase the occurrence of encephalopathy after liver transplantation.

Identification of bacterial infections and clinical manifestation associated with cytomegalovirus in liver transplantation patients.

INTRODUCTION: Liver transplantation has become the most effective therapy for the treatment of patients with end-stage liver disease. With new immunosuppressive agents the incidence of acute rejection has been significantly reduced, but infection has become a serious problem. OBJECTIVE: Our objective was to correlate cytomegalovirus (CMV) positivity of antigenemia and polymerase chain reaction (PCR) with clinical manifestations and bacterial infections among patients undergoing liver transplantation. METHODS: This prospective study included patients monitored for 6 months for early detection of CMV infection. Sample collections were performed at the time of surgery and weekly until the second month followed by fortnightly in the third month, and monthly in the fourth to sixth month. CMV infection was defined by positive antigenemia (>3 cells) or 2 positive PCR tests associated or not with clinical symptoms. The methodology for the diagnosis of bacterial infection was through biochemical tests and the automated VITEK/bioMérieux (identification and antibiogram) using samples of urine and blood cultures. Chi-square test was used for dicotomic variables with significant differences when P < .05. RESULTS: Sixteen patients (32%) had CMV infections, including 13 (81%) with concomitant infections. Thirty-four patients (68%) did not have CMV infections and 8 of these (24%) had bacterial infection. There was a high correlation with bacterial infections among CMV-positive patients. CONCLUSION: Bacterial infections after liver transplantation were associated with CMV infection.

Co-infection and clinical impact of human herpesvirus 5 and 6 in liver transplantation.

BACKGROUND: Human herpesvirus (HHV) 5 and 6 remain latent after primary infection and can be reactivated after immunosuppression for organ transplantation. An association between HHV-5 and HHV-6 has been reported in liver transplant patients. The coinfection is associated with clinical manifestations and graft dysfunction. OBJECTIVE: The aim of this study was to monitor herpesviruses in liver transplant recipients to better understand issues involving coinfection with HHV-5/6 and correlations with acute cellular rejection episodes and bacterial infections. METHODS: Forty-five adult liver transplant patients of median age 47 years (range, 18-66), gave blood samples and liver biopsies in the first 6 months after their surgeries. Viremia was detected with the use of nested PCR and antigenemia; the Banff classification was used to detect allograft rejection. RESULTS: IgG positive for HHV-5 was observed in 94% of subjects whose main indication (67%) for transplantation was hepatitis C. Twenty-three (51.1%) displayed cytomeg virus (CMV) infections and 12 (26.7%) HHV-6 infection. There were 6 patients (13.3%) with HHV-5/6 coinfections. Eighteen of the 23 patients had CMV disease, showing a strong correlation between a positive test and CMV disease; 6 displayed an acute cellular rejection episode in the same period (χ(2) = 6.62; P < .03). Four out of 6 patients who displayed coinfections (HHV-5/6) had concomitant bacterial infections; 3/6 experienced graft rejection episodes. During follow-up, 1 patient had HHV-6 infection diagnosed as encephalitis followed by fever on the 24th day after surgery. The median 32 days for HHV-6 detection by nested PCR positivity was shorter than 38 days for HHV-5. CONCLUSIONS: HHV-5/6-infected patients displayed more allograft rejection episodes, coinfections, and concomitant bacterial infections, besides an higher risk for CMV disease.

Personal health and consumer informatics.

OBJECTIVES: To summarize current outstanding research in the field of Personal Health and Consumers Informatics. METHODS: A selection of excellent research articles published in 2011 in the field of Personal Health Informatics and Consumer Informatics. RESULTS AND CONCLUSIONS: This selection of articles shows that Personal Health Informatics is changing. Indeed, the different solutions tended to the doctors and their interaction, but also tended to the patient in order for him to be more active in his own medical healthcare. The consumer section highlights the development of the social network and the possible limitations.

Characterization and modelling of the heat transfers in a pilot-scale reactor during composting under forced aeration.

The paper focused on the modelling of the heat transfers during composting in a pilot-scale reactor under forced aeration. The model took into account the heat production and the transfers by evaporation, convection between material and gas crossing the material, conduction and surface convection between gas and material in bottom and upper parts of the reactor. The model was adjusted thanks to the measurements practised during fifteen composting experiments in which five organic wastes were, each, composted under three constant aeration rates. Heat production was considered proportional to oxygen consumption rate and the enthalpy per mole oxygen consumed was assumed constant. The convective heat transfer coefficients were determined on basis of the continuous measurements of the temperatures of both the lid and the bottom part of the reactor. The model allowed a satisfying prediction of the temperature of the composting material. In most cases, the mean absolute discard between the experimental and the simulated temperatures was inferior to 2.5°C and the peaks of temperature occurred with less than 8h delay. For the half of the experiments the temperature discard between the simulated peak and the experimental one was inferior to 5°C. On basis of the calculation of a stoichiometric production of water through oxidation of the biodegradable organic matter, the simulation of water going out from material as vapour also allowed a rather satisfying prediction of the mass of water in final mixture. The influence of the aeration rate on every type of heat loss was characterized. Finally, the model was used to evaluate the impacts on material temperature caused by the change of the insulation thickness, the ambient temperature, take the lid away, the increase or the decrease of the mass of waste to compost.

Decision support: time for collaboration.

OBJECTIVES: To summarize current outstanding research in the field of decision support. METHODS: A selection of excellent research articles published in 2010 in the field of computerized clinical decision support systems. RESULTS AND CONCLUSIONS: This selection of articles shows that decision support systems (DSS) are getting better integrated into the electronic health record systems (EHR) and into the clinician's workflow. As a result, there is a better collaboration between physicians and DSS, which improves the care of patients.

Cytomegalovirus, human herpesvirus-6, and human herpesvirus-7 in adult liver transplant recipients: diagnosis based on antigenemia.

Human herpesvirus (HHV)-6, HHV-7, and cytomegalovirus (CMV) that remain latent after primary infection can be reactivated during immunosuppression following organ transplantation in liver transplant recipients. The aim of this study was to monitor active infections for HHV-6, HHV-7, and CMV among adult liver transplantation recipients using antigenemia detected by an immunoperoxidase staining. Twenty-eight adult liver transplant patients were monitored using antigenemia in blood samples obtained at the time of transplantation, as well as weekly in the first month and once a month for 6 months. Of these patients, 28.5% showed positive CMV antigenemia; 39.2%, HHV-6 antigenemia; and 14.2%, HHV-7 antigenemia. The detection of the three viruses was considered to be independent of one another (P>.05). The results described above showed that few patients remain free of beta herpesviruses after liver transplantation. Most patients were infected sequentially and not concurrently. Antigenemia has been considered useful to detect active HHV-6 and HHV-7 infections. Antigenemia can be more efficiently interpreted when compared with polymerase chain reaction results, although other studies are necessary to establish the reference of HHV-6 and HHV-7 antigenemia.

Monitoring and detection of cytomegalovirus in liver transplant recipients.

Cytomegalovirus (CMV) is a ß-herpesvirus. CMV infections are a common complication contributing to morbidity and mortality after liver transplantation. Among organ transplant recipients, CMV can reactivate from latency during the first 6 months. This prospective study performed from February 2008 to December 2009 examined liver transplant recipients during the first 6 months. Two methods were performed to detect CMV infections: antigenemia (AGM) and nested (PCR). Ninety-four patients, including 72 men (76.6%) and 22 women (23.4%) underwent liver transplantation during this period. We analyzed 575 samples including 465 for AGM and PCR. Forty-three (9.25%) showed positive AGM as detected 2 to 179 days posttransplantation with a mean of 50 days and a median of 35 days, and 93/465 (20%) showed positive PCR at 0 to 186 days posttransplantation with a mean of 31 days and a median of 38 days. Among the 43 antigenemia patients, 38 samples were positive for up to 5 cells 18 of which were PCR-positive. Five samples were positive with more than 5 cells, including 3 that were PCR-positive. Only 4.51% had AGM and were PCR-positive in the same sample. Despite only 9.25% (43/465) showing AGM, the current study suggested the utility of routine monitoring to detect early CMV infection among liver transplantation patients seeking to reduce morbidity and mortality.

Comparison of five organic wastes regarding their behaviour during composting: part 2, nitrogen dynamic.

This paper aimed to compare household waste, separated pig solids, food waste, pig slaughterhouse sludge and green algae regarding processes ruling nitrogen dynamic during composting. For each waste, three composting simulations were performed in parallel in three similar reactors (300 L), each one under a constant aeration rate. The aeration flows applied were comprised between 100 and 1100 L/h. The initial waste and the compost were characterized through the measurements of their contents in dry matter, total carbon, Kjeldahl and total ammoniacal nitrogen, nitrite and nitrate. Kjeldahl and total ammoniacal nitrogen and nitrite and nitrate were measured in leachates and in condensates too. Ammonia and nitrous oxide emissions were monitored in continue. The cumulated emissions in ammonia and in nitrous oxide were given for each waste and at each aeration rate. The paper focused on process of ammonification and on transformations and transfer of total ammoniacal nitrogen. The parameters of nitrous oxide emissions were not investigated. The removal rate of total Kjeldahl nitrogen was shown being closely tied to the ammonification rate. Ammonification was modelled thanks to the calculation of the ratio of biodegradable carbon to organic nitrogen content of the biodegradable fraction. The wastes were shown to differ significantly regarding their ammonification ability. Nitrogen balances were calculated by subtracting nitrogen losses from nitrogen removed from material. Defaults in nitrogen balances were assumed to correspond to conversion of nitrate even nitrite into molecular nitrogen and then to the previous conversion by nitrification of total ammoniacal nitrogen. The pool of total ammoniacal nitrogen, i.e. total ammoniacal nitrogen initially contained in waste plus total ammoniacal nitrogen released by ammonification, was calculated for each experiment. Then, this pool was used as the referring amount in the calculation of the rates of accumulation, stripping and nitrification of total ammoniacal nitrogen. Separated pig solids were characterised by a high ability to accumulate total ammoniacal nitrogen. Whatever the waste, the striping rate depended mostly on the aeration rate and on the pool concentration in biofilm. The nitrification rate was observed as all the higher as the concentration in total ammoniacal nitrogen in the initial waste was low. Thus, household waste and green algae exhibited the highest nitrification rates. This result could mean that in case of low concentrations in total ammoniacal nitrogen, a nitrifying biomass was already developed and that this biomass consumed it. In contrast, in case of high concentrations, this could traduce some difficulties for nitrifying microorganisms to develop.

Comparison of five organic wastes regarding their behaviour during composting: part 1, biodegradability, stabilization kinetics and temperature rise.

This paper aims to compare household waste, separated pig solids, food waste, pig slaughterhouse sludge and green algae regarding their biodegradability, their stabilization kinetics and their temperature rise during composting. Three experiments in lab-scale pilots (300 L) were performed for each waste, each one under a constant aeration rate. The aeration rates applied were comprised between 100 and 1100 L/h. The biodegradability of waste was expressed as function of dry matter, organic matter, total carbon and chemical oxygen demand removed, on one hand, and of total oxygen consumption and carbon dioxide production on the other. These different variables were found closely correlated. Time required for stabilization of each waste was determined too. A method to calculate the duration of stabilization in case of limiting oxygen supply was proposed. Carbon and chemical oxygen demand mass balances were established and gaseous emissions as carbon dioxide and methane were given. Finally, the temperature rise was shown to be proportional to the total mass of material biodegraded during composting.

Influence of aeration rate on nitrogen dynamics during composting.

The paper aimed to study the influence of aeration rate on nitrogen dynamics during composting of wastewater sludge with wood chips. Wastewater sludge was sampled at a pig slaughterhouse 24h before each composting experiment, and mixtures were made at the same mass ratio. Six composting experiments were performed in a lab reactor (300 L) under forced aeration. Aeration flow was constant throughout the experiment and aeration rates applied ranged between 1.69 and 16.63 L/h/kg DM of mixture. Material temperature and oxygen consumption were monitored continuously. Nitrogen losses in leachates as organic and total ammoniacal nitrogen, nitrite and nitrate, and losses in exhaust gases as ammonia were measured daily. Concentrations of total carbon and nitrogen i.e., organic nitrogen, total ammoniacal nitrogen, and nitrite and nitrate were measured in the initial substrates and in the composted materials. The results showed that organic nitrogen, which was released as NH4+/NH3 by ammonification, was closely correlated to the ratio of carbon removed from the material to TC/N(org) of the initial substrates. The increase of aeration was responsible for the increase in ammonia emissions and for the decrease in nitrogen losses through leaching. At high aeration rates, losses of nitrogen in leachates and as ammonia in exhaust gases accounted for 90-99% of the nitrogen removed from the material. At low aeration rates, those accounted for 47-85% of the nitrogen removed from the material. The highest concentrations of total ammoniacal nitrogen in composts occurred at the lowest aeration rate. Due to the correlation of ammonification with biodegradation and to the measurements of losses in leachates and in exhaust gases, the pool NH4+/NH3 in the composting material was calculated as a function of time. The nitrification rate was found to be proportional to the mean content of NH4+/NH3 in the material, i.e., initial NH4+/NH3 plus NH4+/NH3 released by ammonification minus losses in leachates and in exhaust gases. The aeration rate was shown to be a main parameter affecting nitrogen dynamics during composting since it controlled the ammonification, the ammonia emission and the nitrification processes.

Influence of aeration rate and biodegradability fractionation on composting kinetics.

The influences of aeration rate and biodegradability fractionation on biodegradation kinetics during composting were studied. The first step was the design of a suitable lab-reactor that enabled the simulation of composting. The second step comprised of composting trials of six blends of sludge (originating from a food processing effluent) with wood chips using aeration rates of 1.69, 3.62, 3.25, 8.48, 11.98 and 16.63 L/h/kg DM of mixture. Biodegradation was evaluated by respiration measurements and from the analysis of the substrate (dry matter, organic matter, total carbon and chemical oxygen demand removal). Continuous measurement of oxygen consumption was coupled with the analysis of initial substrate and composted product for chemical oxygen demand (in the soluble and non-soluble fractions), which enabled an evaluation of the organic matter biodegradability. Oxygen requirements to remove both the easily and slowly biodegradable fractions were determined. Dividing the substrate into different parts according to biodegradability allowed explanation of the influence of aeration rate on stabilization kinetics. Considering that the biodegradation kinetics were of the first-order, the kinetic constants of the easily and slowly biodegradable fractions were calculated as a function of temperature. The methodology presented here allows the comparison of organic wastes in terms of their content of easily and slowly biodegradable fractions and the respective biodegradation kinetics.