First principles of hydrazine electrooxidation at oxide-free and oxide-based palladium electrodes in complex media.

In this study, fundamental aspects that have impact on the electroanalytical detection of hydrazine in phosphate, acetate and yeast fermentation medium in an analytically significant concentration range by several types of palladium (Pd)-modified electrodes, namely, Pd-ink, Pd-sputtered films and palladium nanoparticles (Pd-NPs) were systematically studied. The efficiency of hydrazine electrooxidation is not affected by the composition of multicomponent medium (i), presence of oxygen (ii), morphology or electroactive area (iii), but more likely depends on the purity degree of the electrode surface from residual palladium oxides (iv). In addition, using advanced methods of nanoanalytics and quantum chemistry, the crucial role of hydrazine surface adsorption (v) on oxide-free and oxide-based Pd-electrodes is highlighted. The obtained knowledge will provide future development strategies of electrodes based on nanoparticles of noble metals for tuned and efficient hydrazine electrooxidation in complex fermentation media.

Genomic alterations accompanying tumour evolution in colorectal cancer: tracking the differences between primary tumours and synchronous liver metastases by whole-exome sequencing.

BACKGROUND: Colorectal cancer (CRC) patients with metastatic disease can become cured if neoadjuvant treatment can enable a resection. The search for predictive biomarkers is often performed on primary tumours tissue. In order to assess the effectiveness of tailored treatment in regard to the primary tumour the differences in the genomic profile needs to be clarified. METHODS: Fresh-frozen tissue from primary tumours, synchronous liver metastases and adjacent normal liver was collected from 21 patients and analysed by whole-exome sequencing on the Illumina HiSeq 2500 platform. Gene variants designated as 'damaging' or 'potentially damaging' by Ingenuity software were used for the subsequent comparative analysis. BAM files were used as the input for the analysis of CNAs using NEXUS software. RESULTS: Shared mutations between the primary tumours and the synchronous liver metastases varied from 50 to 96%. Mutations in APC, KRAS, NRAS, TP53 or BRAF were concordant between the primary tumours and the metastases. Among the private mutations were well-known driver genes such as PIK3CA and SMAD4. The number of mutations was significantly higher in patients with right- compared to left-sided tumours (102 vs. 66, p = 0.004). Furthermore, right- compared to left-sided tumours had a significantly higher frequency of private mutations (p = 0.023). Similarly, CNAs differed between the primary tumours and the metastases. The difference was mostly comprised of numerical and segmental aberrations. However, novel CNAs were rarely observed in specific CRC-relevant genes. CONCLUSION: The examined primary colorectal tumours and synchronous liver metastases had multiple private mutations, indicating a high degree of inter-tumour heterogeneity in the individual patient. Moreover, the acquirement of novel CNAs from primary tumours to metastases substantiates the need for genomic profiling of metastases in order to tailor metastatic CRC therapies. As for the mutational status of the KRAS, NRAS and BRAF genes, no discordance was observed between the primary tumours and the metastases.

The gut microbiome is associated with behavioural task in honey bees.

The gut microbiome is recognised as playing an integral role in the health and ecology of a wide variety of animal taxa. However, the relationship between social behavioural traits and the microbial community has received little attention. Honey bees are highly social and the workers perform different behavioural tasks in the colony that cause them to be exposed to different local environments. Here we examined whether the gut microbial community composition of worker honey bees is associated with the behavioural tasks they perform, and therefore also the local environment they are exposed to. We set up five observation hives, in which all workers were matched in age and observed the behaviour of marked bees in each colony over 4 days. The gut bacterial communities of bees seen performing predominantly foraging or predominantly in nest tasks were then characterised and compared based on amplicon sequencing of the 16S rRNA gene. Our results show that some core members of the unique honey bee gut bacterial community are represented in different relative abundances in bees performing different behavioural tasks. The differentially represented bacterial taxa include some thought to be important in carbohydrate metabolism and transport, and also linked to bee health. The results suggest an influence of task-related local environment exposure and diet on the honey bee gut microbial community and identify focal core taxa for further functional analyses.

Oral contraceptive use and reproductive factors and risk of ovarian cancer in the European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: It is well established that parity and use of oral contraceptives reduce the risk of ovarian cancer, but the associations with other reproductive variables are less clear. METHODS: We examined the associations of oral contraceptive use and reproductive factors with ovarian cancer risk in the European Prospective Investigation into Cancer and Nutrition. Among 327,396 eligible women, 878 developed ovarian cancer over an average of 9 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models stratified by centre and age, and adjusted for smoking status, body mass index, unilateral ovariectomy, simple hysterectomy, menopausal hormone therapy, and mutually adjusted for age at menarche, age at menopause, number of full-term pregnancies and duration of oral contraceptive use. RESULTS: Women who used oral contraceptives for 10 or more years had a significant 45% (HR, 0.55; 95% CI, 0.41-0.75) lower risk compared with users of 1 year or less (P-trend, <0.01). Compared with nulliparous women, parous women had a 29% (HR, 0.71; 95% CI, 0.59-0.87) lower risk, with an 8% reduction in risk for each additional pregnancy. A high age at menopause was associated with a higher risk of ovarian cancer (>52 vs ≤ 45 years: HR, 1.46; 95% CI, 1.06-1.99; P-trend, 0.02). Age at menarche, age at first full-term pregnancy, incomplete pregnancies and breastfeeding were not associated with risk. CONCLUSION: This study shows a strong protective association of oral contraceptives and parity with ovarian cancer risk, a higher risk with a late age at menopause, and no association with other reproductive factors.

[Real-time feedback systems for improvement of resuscitation quality]. / Echtzeit-Feedback-Systeme zur Verbesserung der Reanimationsqualität.

The quality of chest compression is a determinant of survival after cardiac arrest. Therefore, the European Resuscitation Council (ERC) 2010 guidelines on resuscitation strongly focus on compression quality. Despite its impact on survival, observational studies have shown that chest compression quality is not reached by professional rescue teams. Real-time feedback devices for resuscitation are able to measure chest compression during an ongoing resuscitation attempt through a sternal sensor equipped with a motion and pressure detection system. In addition to the electrocardiograph (ECG) ventilation can be detected by transthoracic impedance monitoring. In cases of quality deviation, such as shallow chest compression depth or hyperventilation, feedback systems produce visual or acoustic alarms. Rescuers can thereby be supported and guided to the requested quality in chest compression and ventilation. Feedback technology is currently available both as a so-called stand-alone device and as an integrated feature in a monitor/defibrillator unit. Multiple studies have demonstrated sustainable enhancement in the education of resuscitation due to the use of real-time feedback technology. There is evidence that real-time feedback for resuscitation combined with training and debriefing strategies can improve both resuscitation quality and patient survival. Chest compression quality is an independent predictor for survival in resuscitation and should therefore be measured and documented in further clinical multicenter trials.

[Do sociodemographic factors influence emergency medical missions? : analysis in the City of Münster]. / Beeinflussen soziodemografische Faktoren Notarzteinsätze? : Analyse in der Stadt Münster.

BACKGROUND: Demographic development and changes in healthcare utilization have led to a rising number of calls for emergency services. In Germany life-threatening situations are responded by physician-staffed ambulances in a 2-tier system whereas paramedic-staffed ambulances are dispatched in non-life-threatening emergencies. A nationwide protocol guides dispatchers in triage decisions. In the years 1999 to 2009 a continuous rise in the number of calls for a physician-staffed ambulance in Münster was recorded. The degree of healthcare utilization according to socioeconomic status and age structure was retrospectively examined. METHODS: For the year 2006 all emergency calls in the City of Münster responded to by physician-staffed ambulances were analyzed. Each call was assigned to 1 of the 45 urban districts. The local incidence of emergency calls (calls/100 residents/year) was determined and compared to the socioeconomic status which was defined as the percentage of welfare and unemployment benefit recipients per district. Patient condition was assessed by the Munich National Advisory Committee for Aeronautics (M-NACA) score. This scoring system allows calls to be allocated to either life-threatening conditions or non-life-threatening conditions by objective vital parameters. The age structure of the emergency callers was also examined. RESULTS: Urban districts with a low socioeconomic status showed a higher incidence of emergency calls requiring physician-staffed ambulance responses than districts with a high socioeconomic status. Measured by the M-NACA scoring system, the fraction of life-threatening emergencies among all calls proved to be equal to districts with a high socioeconomic status. A correlation between elderly patients and increasing numbers of life-threatening emergencies was found. CONCLUSIONS: A low socioeconomic status of an urban district will result in more ambulance responses. However, the proportion of life-threatening emergencies is equal to districts with a high socioeconomic status. Thus, the greater need for physician-staffed ambulance responses matches clinical needs and legitimates current resource use in a 2-tier ambulance system. Indications for the abuse of physician-staffed ambulances were not found. Considering an aging population the number of emergency calls will rise in the future.

Structural requirements regulate endoproteolytic release of the L-selectin (CD62L) adhesion receptor from the cell surface of leukocytes.

L-selectin mediates leukocyte rolling on vascular endothelium at sites of inflammation and lymphocyte migration to peripheral lymph nodes. L-selectin is rapidly shed from the cell surface after leukocyte activation by a proteolytic mechanism that cleaves the receptor in a membrane proximal extracellular region. This process may allow rapid leukocyte detachment from the endothelial surface before entry into tissues. In this study, the structural requirements for regulation of human L-selectin endoproteolytic release were examined through analysis of chimeric selectin molecules and mutant L-selectin receptors. The use of chimeric selectins and a cytoplasmic tail truncation mutant demonstrated that the extracellular membrane-proximal 15-amino acid region of L-selectin is required for endoproteolytic release. The introduction of alanine-scanning mutations within this membrane-proximal region did not prevent endoproteolytic release, indicating that a specific amino acid motif was not an absolute requirement for cleavage. Furthermore, alterations within the putative primary cleavage site (K283-S284) resulted in either constitutive endoproteolytic release of the receptor or inhibition of cell activation-induced shedding to variable extents. The length of the membrane-proximal region was also critical since truncations of this region completely abolished endoproteolytic release. Thus, release of L-selectin is likely to be regulated by the generation of an appropriate tertiary conformation within the membrane-proximal region of the receptor which allows recognition by a membrane-bound endoprotease with relaxed sequence specificity that cleaves the receptor at a specific distance from the plasma membrane. These observations suggest a generalized protein-processing pathway involved in the endoproteolytic release of specific transmembrane proteins which harbor widely differing primary sequences at or neighboring their cleavage sites.

Identification of the ligand-binding domains of CD22, a member of the immunoglobulin superfamily that uniquely binds a sialic acid-dependent ligand.

CD22 is a B cell-restricted member of the immunoglobulin (Ig) superfamily that functions as an adhesion receptor for leukocytes and erythrocytes. CD22 is unique among members of the Ig superfamily in that it has been suggested to bind a series of sialic acid-dependent ligands, potentially through different functional domains expressed by different splice variants of CD22. In this study, the epitopes identified by a large panel of function-blocking and non-function-blocking CD22 monoclonal antibodies were localized to specific Ig-like domains, revealing that all function-blocking monoclonal antibodies bound to the first and/or second Ig-like domains. Consistent with a single ligand-binding region, the two amino-terminal domains were the functional unit that mediated CD22 adhesion with lymphocytes, neutrophils, monocytes, and erythrocytes. The predominant cell surface species of CD22 was a full length 140,000 relative molecular mass seven Ig-like domain glycoprotein and a minor 130,000 relative molecular mass form lacking the fourth domain. While the two amino-terminal Ig-like domains of CD22 are structurally similar to those found in other members of the Ig superfamily involved in cell adhesion and containing an amino acid sequence motif associated with integrin recognition, site-directed mutagenesis of critical residues surrounding this motif did not disrupt CD22-mediated adhesion. These results demonstrate that the unique ligand-binding properties of CD22 are distinct from those of other members of the Ig superfamily involved in integrin-mediated cell adhesion.

On the Σ classes in E6.

In E6, the cone of positive definite quadratic forms is subdivided into Σs subcones and its equivalence classes {\cal E}_{\Sigma _s} are determined for s = 0-3, and 18-21.

Effect of HBO therapy on adipose-derived stem cells, fibroblasts and co-cultures: In vitro study of oxidative stress, angiogenic potential and production of pro-inflammatory growth factors in co-cultures1.

BACKGROUND: A key moderator of wound healing is oxygen. Wound healing is a dynamic and carefully orchestrated process involving blood cells, cytokines, parenchymal cells (i.e. fibroblasts and mesenchymal stem cells) and extracellular matrix reorganization. Human adipose derived stem cells as well as human fibroblasts produce soluble factors, exhibit diverse effects on inflammation and anti inflammation response and are involved in wound healing processes.Hyperbaric oxygen therapy is an effective adjunct treatment for ischemic disorders such as chronic infection or chronic wounds. In vitro effects of hyperbaric oxygen therapy on human cells were presented in many studies except for those on mono- and co-cultures of human adipose derived stem cells and fibroblasts. OBJECTIVE: The aim of this study was to investigate the effects of hyperbaric oxygen therapy on mono- and co-cultures of human adipose derived stem cells and fibroblasts. METHODS: Mono- and co-cultures from human adipose derived stem cells and fibroblasts were established. These cultures were exposed to hyperbaric oxygen therapy every 24 h for five consecutive days. Measuring experiments were performed on the first, third and fifth day. Therapy effects on the expression of VEGF, IL 6 and reactive oxygen species were investigated. RESULTS: After exposure to hyperbaric oxygen, cell culturess showed a significant increase in the expression of VEGF after 3 and 5 days. All cultures showed significantly reduced formation of reactive oxygen species throughout the experiments. The expression of IL-6 decreased during the experiment in mono-cultures of human adipose derived stem cells and co-cultures. In contrast, mono-cultures of human skin fibroblasts showed an overall significantly increased expression of IL-6. CONCLUSIONS: Hyperbaric oxygen therapy leads to immunmodulatory and proangiogenetic effects in a wound-like enviroment of adipose derived stem cells and fibroblasts.

Inhaled iloprost for sarcoidosis associated pulmonary hypertension.

RATIONALE: Patients with sarcoidosis associated pulmonary hypertension (SAPH) have responded to systemic prostacyclin therapy. OBJECTIVES: To determine the rate of response to inhaled prostacyclin, iloprost, in SAPH. METHODS: Sarcoidosis patients with pulmonary hypertension and no evidence for left ventricular dysfunction were enrolled in an open label, prospective study. Patients underwent right heart catheterization and six minute walk (6MW) test. Quality of life was evaluated using several instruments, including the Saint George Respiratory Questionnaire (SGRQ). Patients received 5 mcg of inhaled iloprost every 2-3 hours while awake. After four months of therapy, patients underwent repeat cardiac catheterization, 6 MW test, and completed quality of life questionnaires. MEASUREMENTS AND MAIN RESULTS: Of the 22 patients enrolled, 15 completed all 16 weeks of therapy. The most common reasons for study discontinuation included drug associated cough (3 patients) and compliance with the prescribed number of treatments per day (2 patients). Six patients experienced a 20% or greater decrease in pulmonary vascular resistance (PVR) from baseline with five of these six patients also showing > or = 5 mm Hg reduction in PA mean. Although three patients improved the 6MW distance by at least 30 meters, only one had a decrease in PVR. At 16 weeks a significant decrease was reported in the SGRQ activity score (p = 0.0273), with seven patients having a 4 point or greater decrease. CONCLUSION: Inhaled iloprost as monotherapy was associated with an improvement in pulmonary hemodynamics and quality of life as assessed by the SGRQ activity score in some sarcoidosis patients with SAPH.

On two special classes of parallelohedra in E6.

The cone of positive-definite quadratic forms is subdivided into aggregates of parallelohedra having certain properties. In E6, the Σ-subcones are investigated and, in particular, the Σ0-subcone will be described which first occurs in E6 and which is governed by the group {\cal G}_{E_6^*}. Further the \Sigma_{d+1 \choose 2}\-subcone which is governed by the group {\cal G}_{A_d^*} will be discussed for d = 6.

Modular, tissue-specific, and biodegradable hydrogel cross-linkers for tissue engineering.

Synthetic hydrogels are investigated extensively in tissue engineering for their tunable physicochemical properties but are bioinert and lack the tissue-specific cues to produce appropriate biological responses. To introduce tissue-specific biochemical cues to these hydrogels, we have developed a modular hydrogel cross-linker, poly(glycolic acid)-poly(ethylene glycol)-poly(glycolic acid)-di(but-2-yne-1,4-dithiol) (PdBT), that can be functionalized with small peptide-based cues and large macromolecular cues simply by mixing PdBT in water with the appropriate biomolecules at room temperature. Cartilage- and bone-specific PdBT macromers were generated by functionalization with a cartilage-associated hydrophobic N-cadherin peptide, a hydrophilic bone morphogenetic protein peptide, and a cartilage-derived glycosaminoglycan, chondroitin sulfate. These biofunctionalized PdBT macromers can spontaneously cross-link polymers such as poly(N-isopropylacrylamide) to produce rapidly cross-linking, highly swollen, cytocompatible, and hydrolytically degradable hydrogels suitable for mesenchymal stem cell encapsulation. These favorable properties, combined with PdBT's modular design and ease of functionalization, establish strong potential for its usage in tissue engineering applications.

Inducible heme oxygenase in the kidney: a model for the homeostatic control of hemoglobin catabolism.

We have recently identified and characterized NADPH-dependent microsomal heme oxygenase as the major enzymatic mechanism for the conversion of hemoglobin-heme to bilirubin-IXalpha in vivo. Enzyme activity is highest in tissues normally involved in red cell breakdown, that is, spleen, liver, and bone marrow, but it usually is negligible in the kidney. However, renal heme oxygenase activity may be transiently increased 30- to 100-fold following hemoglobinemia that exceeded the plasma haptoglobin-binding capacity and consequently resulted in hemoglobinuria. Maximal stimulation of enzyme activity in rats is reached 6-16 hr following a single intravenous injection of 30 mg of hemoglobin per 100 g body weight; activity returns to basal levels after about 48 hr. At peak level, total enzyme activity in the kidneys exceeds that of the spleen or liver. Cyclohexamide, puromycin, or actinomycin D, given just before, or within a few hours after, a single intravenous injection of hemoglobin minimizes or prevents the rise in renal enzyme activity; this suggests that the increase in enzyme activity is dependent on continued synthesis of ribonucleic acid and protein. The apparent biological half-life of renal heme oxygenase is about 6 hr. These observations indicate that functional adaptation of renal heme oxygenase activity reflects enzyme induction either directly or indirectly by the substrate, hemoglobin. Filtered rather than plasma hemoglobin appears to regulate renal heme oxygenase activity. Thus, stabilization of plasma hemoglobin in its tetrameric form with bis (N-maleimidomethyl) ether, which diminishes its glomerular filtration and retards it plasma clearance, results in reduced enzyme stimulation in the kidney, but enhances its activity in the liver. These findings suggest that the enzyme is localized in the tubular epithelial cells rather than in the glomeruli and is activated by luminal hemoglobin. Direct support for this concept was obtained by the demonstration of heme oxygenase activity in renal tubules isolated from rabbits that had been injected with hemoglobin.

The structure of Pyrococcus furiosus glutamate dehydrogenase reveals a key role for ion-pair networks in maintaining enzyme stability at extreme temperatures.

BACKGROUND: The hyperthermophile Pyrococcus furiosus is one of the most thermostable organisms known, with an optimum growth temperature of 100 degrees C. The proteins from this organism display extreme thermostability. We have undertaken the structure determination of glutamate dehydrogenase from P. furiosus in order to gain further insights into the relationship between molecular structure and thermal stability. RESULTS: The structure of P. furiosus glutamate dehydrogenase, a homohexameric enzyme, has been determined at 2.2 A resolution and compared with the structure of glutamate dehydrogenase from the mesophile Clostridium symbiosum. CONCLUSIONS: Comparison of the structures of these two enzymes has revealed one major difference: the structure of the hyperthermophilic enzyme contains a striking series of ion-pair networks on the surface of the protein subunits and buried at both interdomain and intersubunit interfaces. We propose that the formation of such extended networks may represent a major stabilizing feature associated with the adaptation of enzymes to extreme temperatures.

Insights into the molecular basis of thermal stability from the structure determination of Pyrococcus furiosus glutamate dehydrogenase.

The structure determination of the glutamate dehydrogenase from the hyperthermophile Pyrococcus furiosus has been completed at 2.2 A resolution. The structure has been compared with the glutamate dehydrogenases from the mesophiles Clostridium symbiosum, Escherichia coli and Neurospora crassa. This comparison has revealed that the hyperthermophilic enzyme contains a striking series of networks of ion-pairs which are formed by regions of the protein which contain a high density of charged residues. Such regions are not found in the mesophilic enzymes and the number and extent of ion-pair formation is much more limited. The ion-pair networks are clustered at both inter domain and inter subunit interfaces and may well represent a major stabilising feature associated with the adaptation of enzymes to extreme temperatures.

Tadalafil therapy for sarcoidosis-associated pulmonary hypertension.

Sarcoidosis-associated pulmonary hypertension (SAPH) is estimated to occur in at least 5% or more of sarcoidosis patients, and it contributes to significant morbidity and mortality. Optimal therapy for SAPH is not well established. We performed a 24-week open-label trial of tadalafil for SAPH at 2 academic medical centers. Subjects were required to have confirmed sarcoidosis plus a right heart catheterization within 12 months of enrollment showing a mean pulmonary artery pressure ≥ 25 mmHg, a pulmonary artery wedge pressure ≤ 15 mmHg, and a calculated pulmonary vascular resistance ≥ 3 Wood units. Subjects received 20 mg/day of tadalafil for the first 4 weeks and then 40 mg/day for the subsequent 20 weeks. Sixteen patients were screened, 12 of whom met criteria for enrollment. At 24 weeks, there was no overall improvement in 6-minute walk distance (6MWD). Five of the 12 subjects dropped out of the study early (2 for social reasons, 3 for medical reasons). There was no significant change in short form 36, St. George's respiratory questionnaire, or maximum Borg dyspnea scores over the 24 weeks. There were no significant adverse events or laboratory abnormalities clearly related to tadalafil in the cohort. The study did not meet the primary end point of change in 6MWD because of the small sample size. Tadalafil was generally safely administered in this cohort of SAPH patients. There was a relatively high dropout rate but no major adverse events and no clinical worsening. Larger studies are needed to explore this question further. (Trial registration: ClinicalTrials.gov identifier: NCT01324999).

Initial formation of a non-covalent enzyme-reagent complex during the inactivation of clostridial glutamate dehydrogenase by Ellman's reagent: determination of the enzyme's dissociation constant for the binary complex with NAD+ from protection studies.

The time-course of reaction between Ellman's reagent (DTNB) and clostridial glutamate dehydrogenase has been investigated over a wide range of reagent concentrations (50-5000 microM) and showed pseudo-first-order kinetics throughout. The reaction was followed both by monitoring loss of enzyme activity and by detection of released thionitrobenzoate through its absorbance at 412 nm, and, when both methods were used for the same DTNB concentration, the pseudo-first-order rate constants were identical within experimental error, suggesting that the two methods detect the same process. The dependence of the rate constants on DTNB concentration clearly shows saturation, with a limiting value of 1.62 x 10(-3) s-1 and a dissociation constant of 1.0 mM governing the formation of the implied non-covalent enzyme-DTNB complex. This information has allowed a detailed analysis of the protection of the enzyme by NAD+, yielding a value of 334 microM for the dissociation constant for the enzyme-coenzyme binary complex. In view of the convenience of protection studies as a means of determining dissociation constants, this study emphasizes the importance of establishing whether a chemical modification reaction follows simple first-order kinetics with respect to the chemical reagent.

CoA-persulphide: a possible in vivo inhibitor of mammalian short-chain acyl-CoA dehydrogenase.

The characteristic green colour of native short-chain acyl-CoA dehydrogenases (EC 1.3.99.2) results from a charge transfer complex between the FAD prosthetic group and a tightly bound molecule of CoA-persulphide. The native enzyme from ox liver mitochondria was found to have about 60% of its FAD cofactor liganded with CoA-persulphide. When artificially fully liganded with CoA-persulphide, this enzyme was inhibited by 90% in comparison to unliganded enzyme. Enzymic activity could be slowly restored by displacing the CoA-persulphide with high concentrations of butyryl-CoA, the enzyme's physiological substrate. The results show that CoA-persulphide is a potent inhibitor of short-chain acyl-CoA dehydrogenase and may have a physiological role in the regulation of beta-oxidation.

A convenient and rapid method for the complete removal of CoA from butyryl-CoA dehydrogenase.

The commercially available gel, 2-pyridyl disulphide hydroxypropyl ether-Sepharose (thiopropyl-Sepharose 6B), can be used to remove bound ligand completely from butyryl-CoA dehydrogenase (EC 1.399.2) in two simple operations. The resultant enzyme forms normal complexes with acetoacetyl-CoA and CoA persulphide, contains no bound CoA as determined by the enzymatic assay for CoA, and retains full catalytic activity.