ABSTRACT
BACKGROUND: Retrocaval ureter is a rare congenital anomaly resulting from anomalous development of inferior vena cava (IVC) and not from anomalous of the ureter. The anomaly always occurs on the right side due to regression of right supracardinal vein and persistence of right posterior cardinal vein. Retrocaval ureter tends to be associated with various vena cava anomalies because of the embryogenesis. We aimed to identify the prevalence of associated congenital venous anomalies (CVA) resulting from cardinal vein development in adults with retrocaval ureter using computed tomography (CT) images. MATERIALS AND METHODS: The study included 22 adults with retrocaval ureter. We evaluated CT findings and determined the incidence of associated CVA using thin slice data sets from CT scanner with 64 or more detectors. We compared the prevalence of CVA in the retrocaval ureter group (mean age: 57 ± 19 years) and in the control group of 6189 adults with normal ureter (mean age: 66 ± 14 years). RESULTS: In the retrocaval ureter group, 4 (18.2%) adults had CVA including double IVC, right double IVC, preisthmic IVC with horseshoe kidney, and preaortic iliac confluence. One of 2 adults with preaortic iliac confluence had right double right IVC. In the control group, 49 (0.79%) adults had CVA including 37 double IVC, 11 left IVC, and 1 IVC interruption azygos continuation. Fifteen horseshow kidneys were found. The prevalence of associated CVA in the retrocaval ureter group was higher than that in the control group (p < 0.001). CONCLUSIONS: Retrocaval ureter is frequently associated with CVA. Various CVA with retrocaval ureter could happen because of abnormal development of not only the right posterior or supra cardinal vein but also other cardinal veins.
Subject(s)
Retrocaval Ureter , Ureter , Adult , Humans , Middle Aged , Aged , Aged, 80 and over , Retrocaval Ureter/diagnostic imaging , Vena Cava, Inferior/diagnostic imaging , Vena Cava, Inferior/abnormalities , Tomography, X-Ray Computed/methods , Ureter/diagnostic imaging , Ureter/abnormalities , Kidney/abnormalitiesABSTRACT
OBJECTIVE: To investigate the criteria, based on fetal TR waveforms in late gestation, to predict biventricular circulation (BV) after birth in cases of tricuspid valve dysplasia (TVD) or Ebstein's anomaly diagnosed during the fetal period. METHODS: We included 35 consecutive cases diagnosed with TVD or Ebstein's anomaly during the fetal period between January 2008 and December 2021 at Kanagawa Children's Medical Center, Kanagawa, Japan. The maximum velocity and change in pressure over time of tricuspid regurgitation (TR) jet (dP/dt), estimated using TR waveforms obtained during the late-gestation period (gestational age ≥ 28 weeks), were collected from patient records. dP/dt was calculated by dividing the change in estimated right ventricular pressure obtained using Bernoulli's principle by the time taken for the TR maximum velocity to change from one-third to two-thirds of its peak value. The outcome was divided into four categories: BV, single ventricular circulation, neonatal death and fetal death. Patients with BV were included in the BV group, while patients with single ventricular circulation, neonatal death or fetal death were included in the non-BV (NBV) group. RESULTS: Overall, 19 and 16 patients were included in the BV and NBV groups, respectively. The median TR maximum velocity was 3.3 (range, 2.4-3.6) m/s in the BV group and 1.9 (range, 1.0-3.3) m/s in the NBV group. There were no cases of postnatal BV in fetuses with TR maximum velocity < 2.4 m/s; cases with TR maximum velocity of 2.4-3.3 m/s were observed in both BV and NBV groups. Receiver-operating-characteristics-curve analysis was performed on the 11 patients in the BV group and five patients in the NBV group with a TR maximum velocity of 2.4-3.3 m/s. dP/dt ≥ 350 mmHg/s and TR maximum velocity ≥ 2.9 m/s were identified as criteria for predicting the outcome in such cases. The performance of dP/dt ≥ 350 mmHg/s in predicting BV after birth in fetuses with TVD or Ebstein's anomaly was higher compared to that of TR maximum velocity ≥ 2.9 m/s (sensitivity, 90.9% vs 72.3% and specificity, 80.0% vs 80.0%, respectively). CONCLUSIONS: In fetuses with TVD or Ebstein's anomaly, the postnatal outcome may be BV or NBV when the TR maximum velocity is 2.4-3.3 m/s. In such cases, by combining the TR maximum velocity with dP/dt ≥ 350 mmHg/s, BV after birth may be predicted with greater accuracy. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.
Subject(s)
Ebstein Anomaly , Perinatal Death , Tricuspid Valve Insufficiency , Child , Infant, Newborn , Female , Humans , Pregnancy , Infant , Ebstein Anomaly/diagnostic imaging , Tricuspid Valve Insufficiency/diagnostic imaging , Tricuspid Valve/diagnostic imaging , Fetal Death , Fetus , Parturition , Retrospective StudiesABSTRACT
PURPOSE: Pheochromocytoma crisis is a life-threatening endocrine emergency that requires prompt diagnosis and treatment. Because of its rarity, sudden onset, and lack of internationally uniform and validated diagnostic criteria, pheochromocytoma crisis remains to be fully clarified. Therefore, we aimed to describe the clinical characteristics and outcomes of pheochromocytoma crisis through a literature review. METHODS: We performed a systematic literature search of PubMed/MEDLINE database, Igaku-Chuo-Zasshi (Japanese database), and Google Scholar to identify case reports of pheochromocytoma crisis published until February 5, 2021. Information was extracted and analyzed from the literature that reported adequate individual patient data of pheochromocytoma crisis in English or Japanese. Cases were also termed as pheochromocytoma multisystem crisis (PMC) if patients had signs of hyperthermia, multiple organ failure, encephalopathy, and labile blood pressure. RESULTS: In the 200 cases of pheochromocytoma crisis identified from 187 articles, the mean patient age was 43.8 ± 15.5 years. The most common symptom was headache (39.5%). The heart was the most commonly damaged organ resulting from a complication of a pheochromocytoma crisis (99.0%), followed by the lungs (44.0%) and the kidney (21.5%). PMC accounted for 19.0% of all pheochromocytoma crisis cases. After excluding 12 cases with unknown survival statuses, the mortality rate was 13.8% (26/188 cases). Multivariable logistic regression analysis revealed that nausea and vomiting were significantly associated with a higher mortality rate. CONCLUSION: Pheochromocytoma can present with different symptomatology, affecting different organ systems. Clinicians should be aware that patients with nausea or vomiting are at a higher risk of death because of pheochromocytoma crisis.
Subject(s)
Adrenal Gland Neoplasms , Pheochromocytoma , Adult , Humans , Middle Aged , Adrenal Gland Neoplasms/diagnosis , Adrenal Gland Neoplasms/epidemiology , Adrenal Gland Neoplasms/therapy , Multiple Organ Failure/complications , Nausea/complications , Pheochromocytoma/diagnosis , Pheochromocytoma/epidemiology , Pheochromocytoma/therapy , Vomiting/complicationsABSTRACT
In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to eV light mainly in a nonlinear Raman-like process. The experimental nonequilibrium results on isotropic superconductors have been explained going beyond the BCS theory including the Higgs mode. Furthermore, in anisotropic d-wave superconductors strong interaction effects with other modes are expected. Here we calculate the Raman contribution of the Higgs mode from a new perspective, including many-body Higgs oscillations effects and their consequences in conventional, spontaneous Raman spectroscopy. Our results suggest a significant contribution to the intensity of the A_{1g} symmetry Raman spectrum in d-wave superconductors. In order to test our theory, we predict the presence of measurable characteristic oscillations in THz quench-optical probe time-dependent reflectivity experiments.
ABSTRACT
In strongly correlated systems the strength of Coulomb interactions between electrons, relative to their kinetic energy, plays a central role in determining their emergent quantum mechanical phases. We perform resonant x-ray scattering on Bi2Sr2CaCu2O8+δ, a prototypical cuprate superconductor, to probe electronic correlations within the CuO2 plane. We discover a dynamic quasi-circular pattern in the x-y scattering plane with a radius that matches the wave vector magnitude of the well-known static charge order. Along with doping- and temperature-dependent measurements, our experiments reveal a picture of charge order competing with superconductivity where short-range domains along x and y can dynamically rotate into any other in-plane direction. This quasi-circular spectrum, a hallmark of Brazovskii-type fluctuations, has immediate consequences to our understanding of rotational and translational symmetry breaking in the cuprates. We discuss how the combination of short- and long-range Coulomb interactions results in an effective non-monotonic potential that may determine the quasi-circular pattern.
ABSTRACT
A 5-year-old male toy poodle was referred for corrective surgery of an atrial septal defect. A sinus venosus-type atrial septal defect (ASD) with partial anomalous venous connection, suspected pulmonary hypertension, and pulmonary edema was confirmed by radiography, echocardiography, and cardiac computed tomography. Thoracic radiographs showed right heart enlargement. Echocardiography revealed right atrial and ventricular dilatation with mild flattening of the interventricular septum. Left-to-right shunt flow through the ASD was observed on color Doppler examination. Surgical correction of the sinus venosus ASD with a partial anomalous pulmonary venous connection was performed under cardiopulmonary bypass. A follow-up evaluation at 1 year after surgery showed resolution of the right-sided volume overload and no evidence of recurrence of ASD. Complications were not observed. Our findings indicate that surgical correction under cardiopulmonary bypass is a valid treatment option for an ASD with a partial anomalous pulmonary venous connection.
Subject(s)
Dog Diseases/surgery , Heart Septal Defects, Atrial/veterinary , Pulmonary Veins/abnormalities , Animals , Cardiopulmonary Bypass/veterinary , Dog Diseases/congenital , Dog Diseases/diagnostic imaging , Dogs , Echocardiography/veterinary , Heart Septal Defects, Atrial/diagnostic imaging , Heart Septal Defects, Atrial/surgery , Hypertension, Pulmonary/veterinary , Male , Pulmonary Veins/surgery , Tomography, X-Ray Computed/veterinary , Treatment OutcomeABSTRACT
An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
The nature of the pseudogap phase of the copper oxides ('cuprates') remains a puzzle. Although there are indications that this phase breaks various symmetries, there is no consensus on its fundamental nature1. Fermi-surface, transport and thermodynamic signatures of the pseudogap phase are reminiscent of a transition into a phase with antiferromagnetic order, but evidence for an associated long-range magnetic order is still lacking2. Here we report measurements of the thermal Hall conductivity (in the x-y plane, κxy) in the normal state of four different cuprates-La1.6-xNd0.4SrxCuO4, La1.8-xEu0.2SrxCuO4, La2-xSrxCuO4 and Bi2Sr2-xLaxCuO6+δ. We show that a large negative κxy signal is a property of the pseudogap phase, appearing at its critical hole doping, p*. It is also a property of the Mott insulator at p ≈ 0, where κxy has the largest reported magnitude of any insulator so far3. Because this negative κxy signal grows as the system becomes increasingly insulating electrically, it cannot be attributed to conventional mobile charge carriers. Nor is it due to magnons, because it exists in the absence of magnetic order. Our observation is reminiscent of the thermal Hall conductivity of insulators with spin-liquid states4-6, pointing to neutral excitations with spin chirality7 in the pseudogap phase of cuprates.
ABSTRACT
Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.
ABSTRACT
Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.
Subject(s)
Carbon Dioxide/analysis , Carbon Sequestration , Geologic Sediments/chemistry , Biomass , Carbon Isotopes , Costa Rica , Geologic Sediments/microbiology , HeliumABSTRACT
BACKGROUND: Improving patients' oral hygiene is an option for preventing postoperative pneumonia that may be caused by aspiration of oral and pharyngeal secretions. Whether preoperative oral care by a dentist can decrease postoperative complications remains controversial. A retrospective cohort study was undertaken to assess the association between preoperative oral care and postoperative complications among patients who underwent major cancer surgery. METHODS: The nationwide administrative claims database in Japan was analysed. Patients were identified who underwent resection of head and neck, oesophageal, gastric, colorectal, lung or liver cancer between May 2012 and December 2015. The primary outcomes were postoperative pneumonia and all-cause mortality within 30 days of surgery. Patient background was adjusted for with inverse probability of treatment weighting using propensity scoring. RESULTS: Of 509 179 patients studied, 81 632 (16·0 per cent) received preoperative oral care from a dentist. A total of 15 724 patients (3·09 per cent) had postoperative pneumonia and 1734 (0·34 per cent) died within 30 days of surgery. After adjustment for potential confounding factors, preoperative oral care by a dentist was significantly associated with a decrease in postoperative pneumonia (3·28 versus 3·76 per cent; risk difference - 0·48 (95 per cent c.i. -0·64 to-0·32) per cent) and all-cause mortality within 30 days of surgery (0·30 versus 0·42 per cent; risk difference - 0·12 (-0·17 to -0·07) per cent). CONCLUSION: Preoperative oral care by a dentist significantly reduced postoperative complications in patients who underwent cancer surgery.
Subject(s)
Dental Care/statistics & numerical data , Neoplasms/surgery , Postoperative Complications/prevention & control , Adult , Aged , Aged, 80 and over , Dental Care/mortality , Humans , Japan/epidemiology , Middle Aged , Neoplasms/mortality , Oral Health/statistics & numerical data , Pneumonia/etiology , Pneumonia/mortality , Postoperative Complications/mortality , Preoperative Care/mortality , Preoperative Care/statistics & numerical data , Propensity Score , Retrospective Studies , Risk FactorsSubject(s)
Cystadenoma, Serous/diagnostic imaging , Cystadenoma, Serous/pathology , Neoplasms, Multiple Primary , Neuroendocrine Tumors/diagnostic imaging , Neuroendocrine Tumors/pathology , Pancreas/diagnostic imaging , Pancreas/pathology , Pancreatic Neoplasms/diagnostic imaging , Pancreatic Neoplasms/pathology , von Hippel-Lindau Disease/complications , Adult , Cholangiopancreatography, Magnetic Resonance , Cystadenoma, Serous/complications , Diffusion Magnetic Resonance Imaging , Female , Humans , Neuroendocrine Tumors/complications , Pancreatic Neoplasms/complications , Tomography, X-Ray ComputedABSTRACT
Electric field effects on magnetism in metals have attracted widespread attention, but the microscopic mechanism is still controversial. We experimentally show the relevancy between the electric field effect on magnetism and on the electronic structure in Pt in a ferromagnetic state using element-specific measurements: x-ray magnetic circular dichroism (XMCD) and x-ray absorption spectroscopy (XAS). Electric fields are applied to the surface of ultrathin metallic Pt, in which a magnetic moment is induced by the ferromagnetic proximity effect resulting from a Co underlayer. XMCD and XAS measurements performed under the application of electric fields reveal that both the spin and orbital magnetic moments of Pt atoms are electrically modulated, which can be explained not only by the electric-field-induced shift of the Fermi level but also by the change in the orbital hybridizations.
ABSTRACT
The aim of increasing the production ratio of endohedral C60 by impinging foreign atoms against C60 is a crucial matter of the science and technology employed towards industrialization of these functional building block materials. Among these endohedral fullerenes, Li+@C60 exhibits a wide variety of physical and chemical phenomena and has the potential to be applicable in areas spanning the medical field to photovoltaics. However, currently, Li+@C60 can be experimentally produced with only â¼1% ratio using the plasma shower method with a 30 eV kinetic energy provided to the impinging Li+ ion. From extensive first-principles molecular dynamics simulations, it is found that the maximum production ratio of Li+@C60 per hit is increased to about 5.1% (5.3%) when a Li+ ion impinges vertically on a six-membered ring of C60 with 30 eV (40 eV) kinetic energy, although many C60 molecules are damaged during this collision. On the contrary, when it impinges vertically on a six-membered ring with 10 eV kinetic energy, the production ratio remains at 1.3%, but the C60 molecules are not damaged at all. On the other hand, when the C60 is randomly oriented, the production ratio reduces to about 3.7 ± 0.5%, 3.3 ± 0.5%, and 0.2 ± 0.03% for 30 eV, 40 eV, and 10 eV kinetic energy, respectively. Based on these observations we demonstrate the possibility of increasing the production ratio by fixing six-membered rings atop C60 using the Cu(111) substrate or UV light irradiation. In order to assess the ideal experimental production ratio, the 7Li solid NMR spectroscopy measurement is also performed for the multilayer randomly oriented C60 sample irradiated by Li+ using the plasma shower method combined with inductively coupled plasma atomic emission spectroscopy (ICP-AES). Time-of-flight mass spectroscopy measurements are also performed to cross check whether Li+@C60 molecules are produced in the sample. The resulting experimental estimate, 4% for 30 eV incident kinetic energy, fully agrees with our simulation results mentioned above, suggesting the consistency and accuracy of our simulations and experiments.
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PURPOSE: We evaluated the efficacy and toxicity of accelerated hypofractionated radiotherapy (ahypof-rt) for central-type small lung tumours. METHODS: Between November 2006 and January 2015, 40 patients with central-type small lung tumours underwent ahypof-rt delivered using 10 MV X-rays and a coplanar 3-field technique. The number of fractions ranged from 24 to 28, with a fraction size of 2.5-3 Gy. A total dose of 69-75 Gy to the isocentre of the planning target volume was administered to each patient. Cumulative survival and local control rates were calculated using the Kaplan-Meier method. RESULTS: The 27 men and 13 women enrolled in the study had a median age of 79 years (range: 60-87 years). The tumour stage was T1a in 9 patients, T1b in 17 patients, and T2a in 14 patients, with a median size of 26.5 cm (range: 11-49 cm). The median follow-up period was 23 months. A complete response was achieved in 3 patients (7.5%), and a partial response, in 17 patients (42.5%). The overall 2-year and 3-year local control rates were 87.3% and 81.8% respectively; the 2-year and 3-year overall survival rates were 78.9% and 66.7% respectively. Grade 3 pneumonitis occurred in 3 patients; no other severe adverse events (≥grade 3) were observed in any patient. CONCLUSIONS: Accelerated hypofractionated radiotherapy using a fraction size of 2.5-3 Gy was highly safe and can be a more effective treatment option than conventional radiotherapy for patients with central-type small lung tumours.
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While efficient and less onerous for the industry, the globalization of clinical drug development may lead to limited efforts to optimize drugs for regional conditions. We examined the association between clinical development pathways, approved doses, and postmarketing safety risks in Japan for 135 new molecular entities approved between 2004 and 2011. The risk of drug-related deaths seemed higher when pharmaceutical companies chose exactly the same dose as in the United States, even after conducting Japanese dose-ranging studies. We also found a positive association with drug-related deaths when the review process was expedited and when Japanese dose-ranging studies were not conducted for nonexpedited drugs. Our findings suggest that the decisions on regional dose settings and the choice of global clinical development pathways are associated in ways that may influence the postmarketing outcomes in the target populations.
Subject(s)
Drug Approval , Product Surveillance, Postmarketing , Dose-Response Relationship, Drug , Humans , Japan , Models, Theoretical , United StatesABSTRACT
BACKGROUND: Open total gastrectomy carries a high risk of surgical-site infection (SSI). This study evaluated the non-inferiority of antimicrobial prophylaxis for 24 compared with 72 h after open total gastrectomy. METHODS: An open-label, randomized, non-inferiority study was conducted at 57 institutions in Japan. Eligible patients were those who underwent open total gastrectomy for gastric cancer. Patients were assigned randomly to continued use of ß-lactamase inhibitor for either 24 or 72 h after surgery. The primary endpoint was the incidence of SSI, with non-inferiority based on a margin of 9 percentage points and a 90 per cent c.i. The secondary endpoint was the incidence of remote infection. RESULTS: A total of 464 patients (24 h prophylaxis, 228; 72 h prophylaxis, 236) were analysed. SSI occurred in 20 patients (8·8 per cent) in the 24-h prophylaxis group and 26 (11·0 per cent) in the 72-h group (absolute difference -2·2 (90 per cent c.i. -6·8 to 2·4) per cent; P < 0·001 for non-inferiority). However, the incidence of remote infection was significantly higher in the 24-h prophylaxis group. CONCLUSION: Antimicrobial prophylaxis for 24 h after total gastrectomy is not inferior to 72 h prophylaxis for prevention of SSI. Shortened antimicrobial prophylaxis might increase the incidence of remote infection. Registration number: UMIN000001062 ( http://www.umin.ac.jp).
Subject(s)
Antibiotic Prophylaxis , Gastrectomy , Stomach Neoplasms/surgery , Surgical Wound Infection/prevention & control , Aged , Ampicillin/administration & dosage , Drug Administration Schedule , Female , Humans , Japan/epidemiology , Logistic Models , Male , Middle Aged , Prospective Studies , Respiratory Tract Infections/epidemiology , Sulbactam/administration & dosage , Surgical Wound Infection/epidemiology , beta-Lactamase Inhibitors/administration & dosageABSTRACT
WHAT IS KNOWN AND OBJECTIVE: Multicriteria decision analysis (MCDA) has been generally considered a promising decision-making methodology for the assessment of drug benefit-risk profiles. There have been many discussions in both public and private sectors on its feasibility and applicability, but it has not been employed in official decision-makings. For the purpose of examining to what extent MCDA would reflect the first-hand, intuitive preference of evaluators in practical pharmaceutical assessments, we conducted a questionnaire survey involving the participation of employees of pharmaceutical companies. METHODS: Showing profiles of the efficacy and safety of four hypothetical drugs, each respondent was asked to rank them following the standard MCDA process and then to rank them intuitively (i.e. without applying any analytical framework). RESULTS AND DISCUSSION: These two approaches resulted in substantially different ranking patterns from the same individuals, and the concordance rate was surprisingly low (17%). Although many respondents intuitively showed a preference for mild, balanced risk-benefit profiles over profiles with a conspicuous advantage in either risk or benefit, the ranking orders based on MCDA scores did not reflect the intuitive preference. WHAT IS NEW AND CONCLUSION: Observed discrepancies between the rankings seemed to be primarily attributed to the structural characteristics of MCDA, which assumes that evaluation on each benefit and risk component should have monotonic impact on final scores. It would be difficult for MCDA to reflect commonly observed non-monotonic preferences for risk and benefit profiles. Possible drawbacks of MCDA should be further investigated prior to the real-world application of its benefit-risk assessment.
Subject(s)
Cost-Benefit Analysis/statistics & numerical data , Pharmaceutical Preparations/administration & dosage , Risk Assessment/statistics & numerical data , Adult , Decision Making , Decision Support Techniques , Female , Humans , Male , Middle Aged , Surveys and Questionnaires , Young AdultABSTRACT
The objective of this crossover experiment was to investigate the effect of a methane inhibitor, 3-nitrooxypropanol (3NOP), on enteric methane emission, methane isotopic composition, and rumen fermentation and microbial profile in lactating dairy cows. The experiment involved 6 ruminally cannulated late-lactation Holstein cows assigned to 2 treatments: control and 3NOP (60 mg/kg of feed dry matter). Compared with the control, 3NOP decreased methane emission by 31% and increased hydrogen emission from undetectable to 1.33 g/d. Methane emissions per kilogram of dry matter intake and milk yield were also decreased 34% by 3NOP. Milk production and composition were not affected by 3NOP, except milk fat concentration was increased compared with the control. Concentrations of total VFA and propionate in ruminal fluid were not affected by treatment, but acetate concentration tended to be lower and acetate-to-propionate ratio was lower for 3NOP compared with the control. The 3NOP decreased the molar proportion of acetate and increase those of propionate, butyrate, valerate, and isovalerate. Deuterium-to-hydrogen ratios of methane and the abundance of (13)CH3D were similar between treatments. Compared with the control, minor (4) depletion in the (13)C/(12)C ratio was observed for 3NOP. Genus composition of methanogenic archaea (Methanobrevibacter, Methanosphaera, and Methanomicrobium) was not affected by 3NOP, but the proportion of methanogens in the total cell counts tended to be decreased by 3NOP. Prevotella spp., the predominant bacterial genus in ruminal contents in this experiment, was also not affected by 3NOP. Compared with the control, Ruminococcus and Clostridium spp. were decreased and Butyrivibrio spp. was increased by 3NOP. This experiment demonstrated that a substantial inhibition of enteric methane emission by 3NOP in dairy cows was accompanied with increased hydrogen emission and decreased acetate-to-propionate ratio; however, neither an effect on rumen archaeal community composition nor a significant change in the isotope composition of methane was observed.