Stent retrieval for free-floating thrombus attached to carotid artery stenosis: A report of two cases.

Background: We report two cases who underwent mechanical thrombectomy using a stent retriever in advance of urgent carotid artery stenting (CAS) for carotid artery stenosis with free-floating thrombus (FFT). Case Description: Two patients showing symptomatic carotid artery stenosis with FFT underwent urgent endovascular surgery due to progressive neurological symptoms. The first case showed an FFT with 70% internal carotid artery (ICA) stenosis. After the completion of the common and external carotid artery balloon and distal ICA filter protection, we deployed a 6-mm-diameter stent retriever in the distal part of the stenosis. The white thrombus was retrieved; the angiographic shadow of the FFT disappeared; and CAS was performed. In the second case, due to a 90% severe stenosis lesion with FFT, balloon angioplasty was performed on the lesion using the push wire of the stent retriever. After angioplasty, the stent retriever was smoothly retrieved, and CAS was performed. Postoperative magnetic resonance imaging showed an increase in cerebral embolism in the first case; however, the patient's neurological symptoms improved. The second case showed in-stent plaque protrusion and required two additional stent placements; the patient showed no worsening of his neurological symptoms. Conclusion: In cases of carotid artery stenosis with FFT, it is technically possible to retrieve a thrombus with a stent retriever. Although thrombus removal may help reduce the risk of ischemic complications in a series of urgent CAS procedures, there are concerns such as mechanical irritation to the carotid artery plaque, and its indications and alternative treatments should be carefully considered.

Evaluation of Serial Intra-Arterial Indocyanine Green Videoangiography in the Surgical Treatment of Cranial and Craniocervical Junction Arteriovenous Fistulae: A Case Series.

BACKGROUND AND OBJECTIVES: Intravenous indocyanine green (IV-ICG) videoangiography is commonly performed to detect blood flow in the microscopic view. However, intra-arterial ICG (IA-ICG) videoangiography provides high-contrast imaging, repeatability within a short period of time, and clear-cut separation of the arterial and venous phases compared with IV-ICG. These features are useful for detecting retrograde venous drainage (RVD) and shunt occlusion in arteriovenous fistulae (AVF) surgery. This study aimed to investigate whether IA-ICG videoangiography can be repeatable within a short period of time and be useful for detecting RVD and shunt occlusion in cranial- and craniocervical junction (CCJ)-AVF surgery. METHODS: Between January 2012 and December 2022, 50 patients were treated with endovascular or surgical intervention for cranial- and CCJ-AVF at Tokushima University Hospital. Of these, 5 patients (6 lesions) underwent open surgery with IA-ICG videoangiography in a hybrid operating room. We analyzed the data of these 5 patients (6 lesions). RESULTS: There were 4/patient (median, range 2-12) and 3.5/lesion (median, range 2-10) intraoperative IA-ICG runs. IA-ICG videoangiography detected RVD in all patients. Clearance of IA-ICG-induced fluorescence was achieved within 30 seconds in all patients at each region of interest. After the disconnection of the fistulae, IA-ICG videoangiography and intraoperative digital subtraction angiography (DSA) confirmed the disappearance of RVD in all patients. There were no complications associated with IA-ICG videoangiography. CONCLUSION: This study showed that IA-ICG videoangiography is repeatable within a short period of time before and after obliteration and can be useful for detecting RVD and shunt occlusion in cranial- and CCJ-AVF surgery. IA-ICG videoangiography also allows intraoperative DSA studies in a hybrid operating room. Considering the recent advancements in hybrid operating rooms, combining IA-ICG videoangiography with intraoperative DSA is a useful strategy for cranial- and CCJ-AVF surgery.

Evaluation of ammonia emission reducing effect by adding waste cooking oil in pilot-scale composting of dairy cattle manure.

OBJECTIVE: In our previous study, we observed that the addition of waste cooking oil (WCO) reduced ammonia (NH3) emissions during laboratory-scale composting of dairy cattle manure under low-aeration condition. Therefore, this study aimed to evaluate the effect of addition of WCO on NH3 emissions reduction during pilot-scale composting of dairy cattle manure, which is close to the conditions of practical composting treatment. METHODS: Composting tests were conducted using pilot-scale composting facilities (1.8 m3 of capacity). The composting mixtures were prepared from manure, sawdust, and WCO. Two treatments were set: without WCO (Control) and with WCO added to 3 wt% of manure (WCO3). Composting was conducted under continuous aeration at 40 L/min, corresponding to 22.2 L/(min‧m3) of the mixture at the start of composting. The changes in temperatures, NH3 concentrations in the exhaust gases, and contents of the composted mixtures were analyzed. Based on these analysis results, the effect of WCO addition on NH3 emissions and nitrogen loss during composting was evaluated. RESULTS: During composting, the temperature increase of the composting mixture became higher, and the decreases of weight and water content of the mixture became larger in WCO3 than in Control. In the decrease of weight, and the residual weight and water content of the mixture, significant differences (p<0.05) were detected between the two treatments at the end of composting. The NH3 concentrations in the exhaust gases tended to be lower in WCO3 than in Control. Nitrogen loss was 21.5% lower in WCO3 than in Control. CONCLUSION: Reduction of NH3 emissions by the addition of WCO under low aeration condition was observed in pilot-scale composting, as well as in laboratory-scale composting. This result suggests that this method is effective in reducing NH3 emissions in practicalscale composting.

Phylogenetic placement of thermophilic ammonium-tolerant bacteria and their distribution in various composts.

OBJECTIVE: Previous studies isolated the thermophilic ammonium-tolerant (TAT) bacterium Bacillus sp. TAT105 that grew in composting swine manure with the assimilation of ammonium nitrogen and reduced ammonia emissions during composting. Those studies also investigated the potential for applications of TAT105 to composting. It was observed that the concentration of TAT bacteria, phylogenetically close to TAT105, increased during composting. The objectives of this study were to identify the phylogenetic placement of these TAT bacteria and investigate their distribution in various composts. METHODS: The phylogenetic placement of TAT105 was examined based on the sequence of 16S ribosomal RNA gene. The genomic DNA homology between TAT105 and the type strains of bacterial species that were phylogenetically close to TAT105 were examined by DNA-DNA hybridization. Moreover, the tolerances of these strains to NH4Cl and NaCl were analyzed using a cultivation method. Concentrations of TAT bacteria in various composts were evaluated using an agar medium specific to TAT bacteria and polymerase chain reaction followed by restriction fragment length polymorphism analysis. RESULTS: TAT105 was most closely related to Bacillus thermolactis and Bacillus kokeshiiformis. Many variants of these species have been detected in various environments, including composts. The type strains of these species displayed TAT characteristics that were similar to those of TAT105. Among the composts examined in this study, TAT bacteria were detected at high concentrations (105 to 109 colony forming units per gram of dry matter) in most of the composts made from cattle manure, swine manure, bark, and excess sludge. CONCLUSION: TAT bacteria comprised B. thermolactis, B. kokeshiiformis, and their phylogenetically close relatives. They were considered to be adaptable to composting of some certain materials, and a favorable target for searching for strains with some useful function that could be applied to composting of these materials.

Long-sheath Introducer-assisted Revascularization (L-SHARE) Technique for Treating Large-vessel Occlusion by a Giant Clot.

Revascularization for common carotid artery (CCA) occlusion might be difficult. We reported our strategy for revascularizing CCA occlusion by giant clots. A 94-year-old woman was transferred to our hospital because of right hemiparesis and aphasia. CCA occlusion and giant clots were detected on ultrasonography. We performed mechanical thrombectomy using a 9-Fr balloon-guiding catheter, stent retriever, and aspiration catheter through a 9-Fr long-sheath introducer [long-sheath introducer-assisted revascularization (L-SHARE) technique]. We successfully recanalized CCA occlusion using this method. The L-SHARE technique might be useful for recanalization of CCA occlusion.

Single-session hematoma removal and transcortical venous approach for coil embolization of an isolated transverse-sigmoid sinus dural arteriovenous fistula in a hybrid operating room: illustrative case.

BACKGROUND: Dural arteriovenous fistula (DAVF) can present with massive hematoma, which sometimes requires emergent removal. Therefore, a surgical strategy for single-session hematoma removal and shunt occlusion in the same surgical field is important. OBSERVATIONS: A 73-year-old man was transferred to the authors' hospital with a headache. Brain computed tomography (CT) revealed an intracerebral hematoma in the right temporoparietal lobe (hematoma volume 12 ml). A cerebral angiogram revealed a right isolated transverse-sigmoid sinus (TSS)-DAVF fed by the occipital artery and middle meningeal artery. There was cortical venous reflux into the Labbé vein and posterior parietal vein. Percutaneous transarterial and transvenous embolization were unsuccessful. The following day, his consciousness level acutely declined with a headache, and brain CT showed hematoma expansion (hematoma volume 41 ml) with a midline shift. Therefore, the authors performed single-session hematoma removal and a transcortical venous approach for coil embolization of an isolated TSS-DAVF in a hybrid operating room. His postoperative course was uneventful. No recurrence was observed 3 months postoperatively on cerebral angiography. LESSONS: Single-session hematoma removal and a transcortical venous approach for coil embolization of an isolated TSS-DAVF is considered in cases with massive hematoma. This strategy is useful, considering recent developments in hybrid operating rooms.

Effect of waste cooking oil addition on ammonia emissions during the composting of dairy cattle manure.

OBJECTIVE: The objective of this study was to evaluate the effect of waste cooking oil (WCO) addition on ammonia (NH3) emissions during the composting of dairy cattle manure under two aeration conditions. METHODS: The composting tests were conducted using the laboratory-scale composting apparatuses (14 L of inner volume). Three composting treatments (Control, WCO1.5, and WCO3, with WCO added at 0 wt%, 1.5 wt%, and 3 wt% of manure, respectively) were performed in two composting tests: aeration rate during composting was changed from 0.55 to 0.45 L/min in Test 1, and fixed at 0.3 L/min in Test 2, respectively. The NH3 emitted and nitrogen losses during the composting were analyzed, and the effect of the addition of WCO on NH3 emissions were evaluated. RESULTS: Both tests indicated that the composting mixture temperature increased while the weight and water content decreased with increasing WCO content of the composting mixtures. On the other hand, the NH3 emissions and nitrogen loss trends observed during composting in Tests 1 and 2 were different from each other. In Test 1, NH3 emissions and nitrogen losses during composting increased with increasing WCO contents of the composting samples. Conversely, in Test 2, they decreased as the WCO contents of the samples increased. CONCLUSION: The WCO addition showed different effect on NH3 emissions during composting under two aeration conditions: the increase in WCO addition ratio increased the emissions under the higher aeration rate in Test 1, and it decreased the emissions under the lower aeration rate in Test 2. To obtain reduction of NH3 emissions by adding WCO with the addition ratio ≤3 wt% of the manure, aeration should be considered.

Factors associated with DWI-ASPECTS score in patients with acute ischemic stroke due to cerebral large vessel occlusion.

BACKGROUND: The Alberta Stroke Program Early CT score (ASPECTS) of patients with acute ischemic stroke at the time of admission varies. It is crucial to select appropriate methods of treatment, such as recombinant tissue-plasminogen activator, and/or endovascular thrombectomy. According to the recent guidelines, endovascular thrombectomy for patients with large vessel occlusion (LVO) and lesion of ischemic tissue that was not yet infarcted is effective. This result demonstrates the importance of patient selection based on neuroradiological imaging. However, there are many patients who are judged as ineligibility for recanalization therapy because of presence of large ischemic core, indicating unfavorable ASPECTS, at the time of admission. We investigated the factors associated with favorable diffusion-weighted image (DWI)-ASPECTS score at the time of admission. METHODS: We studies patients with LVO within 24 h from onset who were admitted into our hospital. We divided them into two groups, with favorable DWI-ASPECTS (≥6), and unfavorable DWI-ASPECTS (<6) at the time of admission. We investigated factors associated with favorable DWI-ASPECTS by evaluation of our patients' severity of clinical symptom, etiology, and radiological findings. RESULTS: This study showed that mild white matter lesion (Fazekas scale ≤1), absence of internal carotid artery (ICA) occlusion and cardioembolic stroke were independent factor of favorable DWI-ASPECTS at the time of admission. (odds ratio 12.92, p < 0.001, odds ratio 0.31, p = 0.001, odds ratio 0.16, p = 0.001, respectively) CONCLUSIONS: Absence of severe white matter lesion, cardioembolic stroke, and ICA occlusion might be associated with favorable DWI-ASPECTS at the time of admission.

High White Blood Cell Count Is a Risk Factor for Contrast-Induced Nephropathy following Mechanical Thrombectomy for Acute Ischemic Stroke.

BACKGROUND: Although mechanical thrombectomy is a standard endovascular therapy for patients with acute ischemic stroke (AIS), the incidence of and risk factors for contrast-induced nephropathy (CIN) following mechanical thrombectomy are infrequently reported. OBJECTIVES: The aim of this study was to investigate the incidence and risk factors for CIN following mechanical thrombectomy for AIS, and whether the incidence of CIN is related to a poor prognosis. METHODS: We examined consecutive patients who underwent a mechanical thrombectomy in the period from January 2014 to March 2018. The patients' clinical backgrounds, treatments, and clinical prognoses were analyzed. CIN was defined as an increase in the serum creatinine level of ≥44.2 µmol/L (0.5 mg/dL) or 25% above baseline within 72 h after exposure to the contrast medium. RESULTS: In total, 80 patients (46 men and 34 women aged 74.5 ± 11.5 years) who met our inclusion criteria were analyzed. CIN occurred in 8.8% (7/80) of the patients following mechanical thrombectomy. Although no patients needed permanent dialysis, 1 required temporary dialysis. The median amount of contrast medium was 109 mL. A comparison between the groups with and without CIN showed a significant difference in white blood cell (WBC) count at the time of admission (11.6 ± 2.7 × 103/µL and 8.1 ± 2.7 × 103/µL; p < 0.01) and the cut-off value was 9.70 × 103/µL. In multivariate analysis, contrast volume/estimated glomerular filtration rate by creatinine and WBC count were significantly associated with the incidence of CIN, with odds ratios of 1.64 (95% CI 1.02-2.65; p = 0.04) and 1.61 (95% CI 1.15-2.25; p < 0.01), respectively. CONCLUSIONS: This study found that CIN occurred in 8.8% of patients with AIS following mechanical thrombectomy. High WBC count was associated with an increased risk of CIN and may be helpful for predicting CIN.

Application of Bacillus sp. TAT105 to reduce ammonia emissions during pilot-scale composting of swine manure.

Thermophilic ammonium-tolerant bacterium Bacillus sp. TAT105 grows and reduces ammonia (NH3) emissions by assimilating ammonium nitrogen during composting of swine feces. To evaluate the efficacy of a biological additive containing TAT105 at reducing NH3 emissions, composting tests of swine manure on a pilot scale (1.8 m3) were conducted. In the TAT105-added treatment, NH3 emissions and nitrogen loss were lower than those in the control treatment without TAT105. No significant difference was detected in losses in the weight and volatile solids between the treatments. Concentration of thermophilic ammonium-tolerant bacteria in the compost increased in both treatments at the initial stage of composting. In the TAT105-added treatment, bacterial concentration reached ~109 colony-forming units per gram of dry matter, several-fold higher than that in the control and stayed at the same level until the end. These results suggest that TAT105 grows during composting and reduces NH3 emissions in TAT105-added treatment.

Characterization of the denitrifying bacterial community in a full-scale rockwool biofilter for compost waste-gas treatment.

The potential denitrification activity and the composition of the denitrifying bacterial community in a full-scale rockwool biofilter used for treating livestock manure composting emissions were analyzed. Packing material sampled from the rockwool biofilter was anoxically batch-incubated with 15N-labeled nitrate in the presence of different electron donors (compost extract, ammonium, hydrogen sulfide, propionate, and acetate), and responses were compared with those of activated sludge from a livestock wastewater treatment facility. Overnight batch-incubation showed that potential denitrification activity for the rockwool samples was higher with added compost extract than with other potential electron donors. The number of 16S rRNA and nosZ genes in the rockwool samples were in the range of 1.64-3.27 × 109 and 0.28-2.27 × 108 copies/g dry, respectively. Denaturing gradient gel electrophoresis analysis targeting nirK, nirS, and nosZ genes indicated that the distribution of nir genes was spread in a vertical direction and the distribution of nosZ genes was spread horizontally within the biofilter. The corresponding denitrifying enzymes were mainly related to those from Phyllobacteriaceae, Bradyrhizobiaceae, and Alcaligenaceae bacteria and to environmental clones retrieved from agricultural soil, activated sludge, freshwater environments, and guts of earthworms or other invertebrates. A nosZ gene fragment having 99% nucleotide sequence identity with that of Oligotropha carboxidovorans was also detected. Some nirK fragments were related to NirK from micro-aerobic environments. Thus, denitrification in this full-scale rockwool biofilter might be achieved by a consortium of denitrifying bacteria adapted to the intensely aerated ecosystem and utilizing mainly organic matter supplied by the livestock manure composting waste-gas stream.

Utilization of Bacillus sp. strain TAT105 as a biological additive to reduce ammonia emissions during composting of swine feces.

Bacillus sp. strain TAT105 is a thermophilic, ammonium-tolerant bacterium that grows assimilating ammonium nitrogen and reduces ammonia emission during composting of swine feces. To develop a practical use of TAT105, a dried solid culture of TAT105 (5.3 × 10(9) CFU/g of dry matter) was prepared as an additive. It could be stored for one year without significant reduction of TAT105. Laboratory-scale composting of swine feces was conducted by mixing the additive. When the additive, mixed with an equal weight of water one day before use, was added to obtain a TAT105 concentration of above 10(7) CFU/g of dry matter in the initial material, the ammonia concentration emitted was lower and nitrogen loss was approximately 22% lower in the treatment with the additive than in the control treatment without the additive. The colony formation on an agar medium containing high ammonium could be used for enumeration of TAT105 in the composted materials.

Effect of electron donors on anammox coupling with nitrate reduction for removing nitrogen from nitrate and ammonium.

Anammox coupling with nitrate reduction under various electron donors was studied using sludge acclimatized to have anammox and denitrification activities. Due to a deficiency in electron donors for NO(3)(-) reduction, anammox activity in an inorganic medium containing NO(3)(-) and NH(4)(+) was lower than that in NO(2)(-) and NH(4)(+). Anammox could use NO(2)(-) competitively against denitrifiers under a very limited NO(2)(-) concentration, and additions of swine wastewater or acetate stimulated anammox activity in an inorganic medium containing NO(3)(-) and NH(4)(+) with no inhibition effects. However, a high concentration of swine wastewater caused an exponential increase in denitrification activity. The addition of hydrogen and iron stimulated anammox activity in an inorganic medium containing NO(3)(-) and NH(4)(+), but iron showed an inhibitory effect on anammox in a medium containing NO(2)(-) and NH(4)(+). Hydrogen was shown to be advantageous since it did not increase denitrification even when its addition was increased.

Effects of struvite formation and nitratation promotion on nitrogenous emissions such as NH3, N2O and NO during swine manure composting.

To reduce nitrogenous emissions from composting, two different countermeasures were applied simultaneously in swine manure composting. One was forming struvite by adding Mg and P at the start of composting, and the other was to promote nitratation (nitrite being oxidized nitrate) by adding nitrite-oxidizing bacteria after the thermophilic phase of composting. In the laboratory- and mid-scale composting experiments, 25-43% of NH3, 52-80% of N2O and 96-99% of NO emissions were reduced. From the nitrogen balance, it was revealed that the struvite formation reduced not only NH3, but also other nitrogenous emissions except N2O. The amount of total nitrogen losses was reduced by 60% by the two combined countermeasures, against 51% by the struvite formation alone. However, the nitratation promotion dissolved struvite crystals due to the pH decline, diminishing the effect of struvite as a slow-release fertilizer.

Distribution of phosphorus, copper and zinc in activated sludge treatment process of swine wastewater.

Changes in swine wastewater chemical features during an activated sludge treatment process were surveyed on 11 farms, and analyzed with non-biodegradable elements, i.e., phosphorus (P), copper (Cu), and zinc (Zn). In piggery wastewater, they were linearly correlated with suspended solid (SS) concentrations and the major portion was in solid fractions. After the pretreatment step, they were removed, with 80% for total P, 85% for total Cu, and 84% for total Zn. After the activated sludge process, total P, Cu, and Zn were then removed at 83%, 96%, and 95%, respectively. Removing SS thoroughly at each step was shown to be the most important factor in preventing outflow of these elements, since there are linear correlations or a positive relationship between the removal of SS concentrations and their removal in solid form. Most of the P, Cu, and Zn in activated sludge effluent was in soluble form, and the concentrations of Cu and Zn in the effluent were low enough, while further P removal might be required.

Characteristics of the microbial community associated with ammonia oxidation in a full-scale rockwool biofilter treating malodors from livestock manure composting.

The relationship between the activity and community structure of microbes associated with the oxidation of ammonia in a full-scale rockwool biofilter was examined by kinetic, denaturing gradient gel electrophoresis (DGGE), and sequence analyses. The packing materials were sampled from two different depths at 3 sites. Estimated K(m) values were similar among depths at same sampling sites, while V(max) differed in the mid-point sample. The lower depth of this site had the highest V(max). A correspondence analysis showed the DGGE profile of ammonia-oxidizing bacterial amoA of the lower depth of the mid-point sample to be distinguishable from the others. Banding patterns at other sites were similar among depths. Banding patterns of ammonia-oxidizing archaeal amoA of the mid-point sample were also similar among depths. The results suggested an association between the ammonia-oxidizing bacterial community's composition and ammonium oxidation kinetics in samples. Sequence analysis indicated that the ammonia-oxidizing bacterial community mainly belonged to the Nitrosomonas europaea lineage and Nitrosospira cluster 3. The ammonia-oxidizing archaeal amoA-like sequences were related to those belonging to soil and sediment groups, including one with 84% nucleotide similarity with Nitrosopumilus maritimus.

Key odor components responsible for the impact on olfactory sense during swine feces composting.

This study aimed to identify the major odor contributing components produced during swine feces composting which have an impact on the olfactory senses. A total of 64 gas samples collected at different stages of composting were analyzed by both a gas chromatograph and human panel test using the triangle odor bag method. Multiple regression analysis of representative odor substances present in the outlet gas was carried out employing the odor index (OI) as the dependent variable and the odor unit as the independent variable. The recorded changes in OI indicated that turning was an important event during odor evolution, and that the odor emission during the thermophilic phase should be the main target for odor abatement. The model incorporating ammonia, methyl mercaptan and dimethyl sulfide as independent variables confirmed the value of the OI (R(2)=0.70). These compounds were identified to be the key odor components significantly determining the OI.

Evaluation of full-scale biofilter with rockwool mixture treating ammonia gas from livestock manure composting.

NH3 removal by a full-scale biofilter with rockwool packing materials was studied by measuring the gases and potential nitrification and denitrification activities of those materials in order to improve the biofiltration technology used in livestock farms. The rockwool biofilter was a durable and effective system for removing NH3, which was varied with the turning of manure composts. Furthermore, NH3 could be treated in the absence of an extra increase in two greenhouse gases, N2O and CH4. Potential nitrification and denitrification activities of the packing materials were estimated to be 8.2-12.2 mg N, and 1.42-4.69 mg N/100 g dry samples per day, respectively. The results suggested that potential nitrification and denitrification activities would increase within the biofilter where substrates, NH3 or NO3(-), have accumulated as a result of its operation. However, since percolate water contained high concentrations of NH4(+) and NO3(-), further improvement is required by reducing nitrogenous compounds within both the biofilter and percolate water.

Removal and recovery of phosphorous from swine wastewater by demonstration crystallization reactor and struvite accumulation device.

A demonstration crystallization reactor and struvite accumulation device for the removal and recovery of phosphorous was constructed and their performance was evaluated using actual swine wastewater for 3.5 years. The wastewater pH was increased by aeration, and the concentrations of total P and soluble PO(4)-P were reduced by a struvite crystallization reaction induced under a high pH condition. A 30% MgCl(2) addition was effective in enhancing the struvite crystallization reaction. The concentrations of suspended solids, total Zn and total Cu, were also decreased by the settling function of the reactor. On removing the efficiencies of these components, no noticeable seasonal fluctuation in performance was observed during the 3.5-year operation. In terms of maximum yield, 171g struvite was obtained from 1m(3) swine wastewater by the demonstration accumulation device for struvite recovery. The recovered struvite needed only air-drying before use since it was approximately 95% pure even without washing.

Reduction of nitrous oxide emission from pig manure composting by addition of nitrite-oxidizing bacteria.

Nitrous oxide (N2O) is emitted from pig manure composting, and the emission correlates with nitrite (NO2-) accumulation in the composting material. In the present study, we added nitrite-oxidizing bacteria (NOB)to inhibit NO2- accumulation and evaluated its effect on N2O emission in a laboratory-scale composting experiment. Mature pig manure compost (MPMC) containing NOB at 10(6) MPN g(-1) WM or cultured MPMC (cul-MPMC) NOB at 10(11) MPN g(-1) WM was added after the thermophilic phase of composting. The addition of these materials prevented NO2- accumulation, promoting oxidation to nitrate (NO3-), whereas the accumulation of NO2- occurred in the material to which NOB was not added as the result of the delayed growth of indigenous NOB compared with that of ammonia-oxidizing bacteria (AOB). The pattern of NO2- in the material agreed with that of N2O emission; therefore, N2O emission ceased rapidly when NOB was added. Emission rates of N2O were 88.5 (no addition), 17.5 (MPMC addition), and 20.2 (cul-MPMC addition) g N-N2O kg(-1) TNinitial, respectively. Improving composition of nitrifying communities for complete nitrification promotion would be useful to establish a composting method with low N2O emission.