Highly CEP-stable optical parametric amplifier at 2†µm with a few-cycle duration and 100 kHz repetition rate.

We develop a BiB3O6 (BiBO)-based optical parametric amplifier in the spectral region around 2 µm using a Yb:KGW amplifier operating at 100 kHz. The two-stage degenerate optical parametric amplification results in a typical output energy of 30 µJ after compression, spectrum covering 1.7-2.5 µm range, and a pulse duration fully compressible down to 16.4 fs, corresponding to 2.3 cycles. Due to the inline difference frequency generation of the seed pulses, the carrier envelope phase (CEP) is passively stabilized without feedback over 11 hours at the level below 100 mrad including a long-term drift. Short-term statistical analysis in the spectral domain further shows a behavior qualitatively different from that of parametric fluorescence, indicating high degree of suppression of optical parametric fluorescence. The high phase stability together with the few-cycle pulse duration is promising for the investigation of high-field phenomena such as subcycle spectroscopy in solids or high harmonics generation.

Real-time observation of the Woodward-Hoffmann rule for 1,3-cyclohexadiene by femtosecond soft X-ray transient absorption.

The stereochemistry of pericyclic reactions is explained by orbital symmetry conservation, referred to as the Woodward-Hoffmann (WH) rule. Although this rule has been verified using the structures of reactants and products, the temporal evolution of the orbital symmetry during the reaction has not been clarified. Herein, we used femtosecond soft X-ray transient absorption spectroscopy to elucidate the thermal pericyclic reaction of 1,3-cyclohexadiene (CHD) molecules, i.e., their isomerization to 1,3,5-hexatriene. In the present experimental scheme, the ring-opening reaction is driven by the thermal vibrational energy induced by photoexcitation to the Rydberg states at 6.2 eV and subsequent femtosecond relaxation to the ground state of CHD molecules. The direction of the ring opening, which can be conrotatory or disrotatory, was the primary focus, and the WH rule predicts the disrotatory pathway in the thermal process. We observed the shifts in K-edge absorption of the carbon atom from the 1s orbital to vacant molecular orbitals around 285 eV at a delay between 340 and 600 fs. Furthermore, a theoretical investigation predicts that the shifts depend on the molecular structures along the reaction pathways and the observed shifts in induced absorption are attributed to the structural change in the disrotatory pathway. This confirms that the orbital symmetry is dynamically conserved in the ring-opening reaction of CHD molecules as predicted using the WH rule.

Elevated expression of B7 homolog 4 is associated with disease progression in upper urinary tract urothelial carcinoma.

BACKGROUND: B7 homolog 4 (B7-H4) is a negative regulator of immune responses, but its immunoregulatory role in the tumor microenvironment of upper urinary tract urothelial carcinoma (UTUC) remains unclear. METHODS: We measured the immunohistochemical expression of B7-H4, CD8 and T cell intracellular antigen 1 (TIA-1), a marker of activated CD8, in 133 patients with UTUC who underwent nephroureterectomy. We also studied the relationship between B7-H4, CD8 and TIA-1 expression and clinicopathological characteristics. RESULTS: B7-H4 was mainly expressed on the surface in tumor cells, while CD8 and TIA-1 were often expressed in tumor-infiltrating lymphocytes. Elevated expression of B7-H4 in tumor cells was associated with a poorer histological grade, higher pT stage, regional lymph node metastasis, lymphovascular invasion, poorer response of recurrent metastatic lesions to systemic chemotherapy and shorter overall survival. Expression of CD-8 or TIA-1 alone did not correlate directly with clinicopathological characteristics, but among the patients with higher B7-H4 expression in the primary tumors, those with higher CD8 or TIA-1 expression had a better response to systemic chemotherapy, and longer survival, than these with lower CD8 or TIA-1 expression. Cox multivariate regression analysis revealed that higher expression of B7-H4 was associated with shorter overall survival. CONCLUSIONS: These findings suggest that B7-H4 expression in the tumor microenvironment influences the progression of UTUC through cancer immunity and metabolic activity. Tumor cell-associated B7-H4 might be a potential target for cancer immunotherapies.

Anatomic Resection for Hepatocellular Carcinoma: Prognostic Impact Assessed from Recurrence Treatment.

BACKGROUND: The oncologic advantage of anatomic resection (AR) for primary hepatocellular carcinoma (HCC) remains controversial. This study aimed to evaluate the clinical advantages of AR for primary HCC by using propensity score-matching and by assessing treatment strategies for recurrence after surgery. METHODS: The study reviewed data of patients who underwent AR or non-anatomic resection (NAR) for solitary HCC (≤ 5 cm) in two institutions between 2004 and 2017. Surgical outcomes were compared between the two groups in a propensity score-adjusted cohort. The time-to-interventional failure (TIF), defined as the elapsed time from resection to unresectable/unablatable recurrence, also was evaluated. RESULTS: The inclusion criteria were met by 250 patients: 77 patients (31%) with AR and 173 patients (69%) with NAR. In the propensity score-matched populations (AR, 67; NAR, 67), the 5-year recurrence-free survival (RFS) for AR was better than for NAR (62% vs 35%; P = 0.005). No differences, however, were found in the 5-year overall survival between the two groups (72% vs 78%; P = 0.666). The 5-year TIF rates for the NAR group (60%) also were similar to those for the AR group (66%) (P = 0.413). In the cohort of 67 patients, curative repeat resection or ablation therapy was performed more frequently for the NAR patients (42%) than for the AR patients (10%) (P < 0.001). CONCLUSION: For solitary HCC, AR decreases recurrence after the initial hepatectomy. However, aggressive curative-intent interventions for recurrence compensate for the impaired RFS, even for patients undergoing NAR.

Impact of post-operative paralytic ileus on post-operative outcomes after surgery for colorectal cancer: a single-institution, retrospective study.

PURPOSE: Post-operative paralytic ileus (POI) occurs after surgery because of gastrointestinal dysfunction caused by surgical invasion. We therefore investigated the frequency of POI after laparoscopic colorectal surgery in patients with colorectal cancer using a strictly defined POI diagnosis and identified associated risk factors. METHODS: Patients who underwent initial laparoscopic surgery for colorectal cancer between January 2014 and December 2018 were included. The primary end point was the incidence of POI. A multivariate logistic regression analysis revealed the contributing risk factors for POI. RESULTS: Of the 436 patients, 94 (21.6%) had POI. Compared with the non-POI group, the POI group had significantly higher frequencies of infectious complications (p < 0.001), pneumonia (p < 0.001), intra-abdominal abscess (p = 0.012), anastomotic leakage (p = 0.016), and post-operative bleeding (p = 0.001). In the multivariate analysis, the right colon (odds ratio [OR] 2.180, p = 0.005), pre-operative chemotherapy (OR 2.530, p = 0.047), pre-operative antithrombotic drug (OR 2.210, p = 0.032), and post-operative complications of CD grade ≥ 3 (OR 12.90, p < 0.001) were independent risk factors for POI. CONCLUSION: Post-operative management considering the risk of post-operative bowel palsy may be necessary for patients with right colon, pre-operative chemotherapy, pre-operative antithrombotic drug or severe post-operative complications.

Laparoscopic cholecystectomy after endoscopic trans-papillary gallbladder stenting for acute cholecystitis: a pilot study of surgical feasibility.

BACKGROUND: Percutaneous transhepatic gallbladder drainage (PTGBD) is indicated for patients with acute cholecystitis (AC) who are not indicated for urgent surgery, but external tubes reduce quality of life (QOL) while waiting for elective surgery. The objective of the present study was to investigate the feasibility of laparoscopic cholecystectomy after endoscopic trans-papillary gallbladder stenting (ETGBS) comparing with after PTGBD. METHODS: Intraoperative and postoperative outcomes of patients with ETGBS and PTGBD were retrospectively compared. RESULTS: Eighteen ETGBS and ten PTGBD patients were compared. Differences in the duration of ETGBS and PTGBD [median 209 min (range 107-357) and median 161 min (range 130-273), respectively, P = 0.10], median blood loss [ETGBS 2 (range 2-180 ml) and PTGBD 24 (range 2-100 ml), P = 0.89], switch to laparotomy (ETGBS 11% and PTGBD 20%, P = 0.52), and median postoperative hospital stay [ETGBS 8 (range 4-24 days) and ETGBS 8 (range 4-16 days), P = 0.99]. Thickening of the cystic duct that occurred in 60% of the ETGBS patients and none of the PTGBD patients (P = 0.005) interfered with closure of the duct by clipping. No obstruction occurred in ETGBS patients. CONCLUSION: ETGBS did not make laparoscopic cholecystectomy less feasible than after PTGBD. This is a pilot study, and further investigations are needed to validate the results of the present study.

Association between serum prostate-specific antigen level and diabetes, obesity, hypertension, and the laboratory parameters related to glucose tolerance, hepatic function, and lipid profile: implications for modification of prostate-specific antigen threshold.

BACKGROUND: Previous studies indicated inverse relationships between body mass index (BMI), diabetes and prostate-specific antigen (PSA) concentration besides an established positive relationship between age and PSA. Other causal relationships between clinical parameters including hypertension, hepatic function, tests, lipid profile and PSA were also suggested. Thus, we incorporated these parameters all together into the analysis to identify possible determinants of PSA concentration to improve the accuracy of PSA tests. METHODS: Associations between PSA and the above-mentioned clinical parameters were examined among 14,486 men who visited our hospital for a routine health checkup, using linear regression analyses. RESULTS: Total of 1403 (9.7%) and 784 (5.4%) men were classified as diabetes and obesity, respectively. After adjusting age, significant PSA reductions were found in diabetic men, especially for men taking antidiabetics. Such association was seen when the diabetic status was represented by hemoglobin A1c (HbA1c) and fasting blood sugar (FBS) levels. That is, PSA levels were significantly reduced in men with higher HbA1c and FBS levels. Obesity was also associated with a reduction in PSA levels. Moreover, PSA levels were significantly decreased with increased ALT levels. CONCLUSIONS: PSA test results should be carefully interpreted especially for men with diabetes and obesity, in whom a substantial reduction in PSA concentration is likely to occur.

Significance of sarcopenia as a prognostic factor for metastatic urothelial carcinoma patients treated with systemic chemotherapy.

BACKGROUND: Recently, numerous studies have reported an association between sarcopenia and poor outcomes in various kinds of malignancies. We investigated whether sarcopenia predicts the survival of patients with metastatic urothelial carcinoma who underwent systemic chemotherapy. METHODS: We reviewed 87 metastatic urothelial carcinoma patients who underwent chemotherapy (gemcitabine plus cisplatin or gemcitabine plus carboplatin for cisplatin-unfit patients) between 2007 and 2015. A computed tomography scan prior to chemotherapy was used for evaluating sarcopenia, and we measured three cross-sectional areas of skeletal muscle at the third lumbar vertebra and calculated the skeletal muscle index (SMI), the paraspinal muscle index (PSMI), and the total psoas area (TPA) of each patient. Predictive values of survival were assessed using Cox regression analysis. RESULTS: The median overall survival (OS) was 16 months (95% CI 13.5-18). Although SMI alone was not a significant predictor of shorter OS (P = 0.117) in univariate analysis, SMI stratified by the value of the body mass index (BMI) was a significant predictor of shorter OS in univariate analysis (P = 0.037) and was also an independent predictor of shorter OS in multivariate analysis (P = 0.026). PSMI and TPA were not significant prognostic factors even when stratified by BMI (P = 0.294 and 0.448), respectively. CONCLUSION: Neither PSMI nor TPA could substitute SMI as a predictor for poor outcomes in metastatic urothelial carcinoma patients treated with systemic chemotherapy in our study. SMI stratified by BMI is a useful predictor of prognosis in these patients.

Time-resolved observation of interatomic excitation-energy transfer in argon dimers.

The ultrafast transfer of excitation energy from one atom to its neighbor is observed in singly charged argon dimers in a time-resolved extreme ultraviolet (XUV)-pump IR-probe experiment. In the pump step, bound 3s-hole states in the dimer are populated by single XUV-photon ionization. The excitation-energy transfer at avoided crossings of the potential-energy curves leads to dissociation of the dimer, which is experimentally observed by further ionization with a time-delayed IR-probe pulse. From the measured pump-probe delay-dependent kinetic-energy release of coincident Ar+ + Ar+ ions, we conclude that the transfer of energy occurs on a time scale of about 800fs. This mechanism represents a fast relaxation process below the energy threshold for interatomic Coulombic decay.

[Diagnostic Impact of 3D-CT with Retrograde Pyelography for Ureteropelvic Junction Obstruction : A Case Report].

A 26-year-old woman presented to our hospital with right costovertebral angle (CVA) pain. Ultrasonographyand computed tomography(CT) scan indicated right hydronephrosis, and MAG3 renogram showed an obstructed pattern in the right kidney. Enhanced CT scan revealed an ureteropelvic junction obstruction (UPJO) with an aberrant vessel. To clarifythe ureteropelvic junction (UPJ) structure in detail, we utilized 3D-CT with retrograde pyelography (RP), which further revealed the true pinhole ureteral stricture of UPJ unaffected bythe aberrant vessel.

Clinically significant association between the maximum standardized uptake value on 18F-FDG PET and expression of phosphorylated Akt and S6 kinase for prediction of the biological characteristics of renal cell cancer.

BACKGROUND: The relationship between the clinicopathological features and molecular changes associated with standardized uptake value (SUV) determined by Positron emission tomography (PET) with [18F] fluorodeoxyglucose (18F-FDG PET) in human renal cell carcinoma (RCC) has not been elucidated. On the other hand, overactivation of the phosphatidylinositol 3'kinase (PI3K), serine/threonine kinase Akt, and mammalian target of rapamycin (mTOR) pathway has been detected in a variety of human cancers, including RCC. So far, little is known about the relationship between the SUV and these proteins in human RCC. Thus, it is important to study the relevance of SUV with clinicopathological features in human RCCs from a molecular point of view. METHODS: Seventy-seven consecutive patients with RCC who underwent nephrectomy and pretreatment determination of the maximum SUV (SUVmax) by 18F-FDG PET were analyzed. We investigated the relationship between the SUVmax, phosphorylated-Akt (Ser-473) (pAkt(Ser-473)), phosphorylated-Akt (Thr-308) (pAkt(Thr-308), and phosphorylated-S6 ribosomal protein (Ser-235/236) (pS6) protein levels in the primary tumor and various clinicopathological features. RESULTS: The average SUVmax of the primary tumor was 6.9 (1.5 to 40.3). A higher SUVmax was correlated with higher expression of pAkt(Ser-473), pAkt (Thr-308), and pS6 protein in the primary tumor. A higher SUVmax and increased expression of pAkt (Ser-473), pAkt (Thr-308), and pS6 of the primary tumor was associated with less tumor differentiation, a higher pT stage, regional lymph node involvement, microscopic vascular invasion, and distant metastasis, as well as with early relapse following radical nephrectomy in patients who had localized or locally advanced RCC without distant metastasis (cTanyNanyM0) and with shorter overall survival in all patients. CONCLUSIONS: A higher SUVmax on 18F-FDG PET is associated with elevated tumor levels of pAkt and pS6 protein and with aggressive behavior and metastatic potential of RCC, as well as with early relapse following radical nephrectomy and shorter overall survival. These findings suggest that SUVmax may be useful for predicting the biological characteristics of RCC.

The Rho-kinase inhibitor HA-1077 suppresses proliferation/migration and induces apoptosis of urothelial cancer cells.

BACKGROUND: Activation of Rho, one of the small GTPases, and its major downstream target Rho-kinase (ROCK) promotes the development and metastasis of cancer. We previously showed that elevation of Rho and ROCK expression was associated with tumor invasion, metastasis, and an unfavorable prognosis in patients with urothelial cancer of the bladder or upper urinary tract. METHODS: We investigated the effects of a ROCK inhibitor on the growth, migration, and apoptosis of bladder cancer cells. We also examined phosphorylation of RhoA (RhoA activity) by measuring its GTP-bound active form and assessed the expression of ROCK to explore the underlying molecular mechanisms. RESULTS: Lysophosphatidic acid (LPA) and geranylgeraniol (GGOH) induced an increase of cell proliferation and migration in association with promotion of RhoA activity and upregulation of ROCK expression. The ROCK inhibitor fasudil (HA-1077) suppressed cell proliferation and migration, and also induced apoptosis in a dose-dependent manner. HA-1077 dramatically suppressed the expression of ROCK-I and ROCK-II, but did not affect RhoA activity. CONCLUSIONS: These findings suggest that ROCK could be a potential molecular target for the treatment of urothelial cancer.

Prostate volume and biopsy tumor length are significant predictors for classical and redefined insignificant cancer on prostatectomy specimens in Japanese men with favorable pathologic features on biopsy.

BACKGROUND: Gleason pattern 3 less often has molecular abnormalities and often behaves indolent. It is controversial whether low grade small foci of prostate cancer (PCa) on biopsy could avoid immediate treatment or not, because substantial cases harbor unfavorable pathologic results on prostatectomy specimens. This study was designed to identify clinical predictors for classical and redefined insignificant cancer on prostatectomy specimens in Japanese men with favorable pathologic features on biopsy. METHODS: Retrospective review of 1040 PCa Japanese patients underwent radical prostatectomy between 2006 and 2013. Of those, 170 patients (16.3%) met the inclusion criteria of clinical stage ≤ cT2a, Gleason score (GS) ≤ 6, up to two positive biopsies, and no more than 50% of cancer involvement in any core. The associations between preoperative data and unfavorable pathologic results of prostatectomy specimens, and oncological outcome were analyzed. The definition of insignificant cancer consisted of pathologic stage ≤ pT2, GS ≤ 6, and an index tumor volume < 0.5 mL (classical) or 1.3 mL (redefined). RESULTS: Pathologic stage ≥ pT3, upgraded GS, index tumor volume ≥ 0.5 mL, and ≥ 1.3 mL were detected in 25 (14.7%), 77 (45.3%), 83 (48.8%), and 53 patients (31.2%), respectively. Less than half of cases had classical (41.2%) and redefined (47.6%) insignificant cancer. The 5-year recurrence-free survival was 86.8%, and the insignificant cancers essentially did not relapse regardless of the surgical margin status. MRI-estimated prostate volume, tumor length on biopsy, prostate-specific antigen density (PSAD), and findings of magnetic resonance imaging were associated with the presence of classical and redefined insignificant cancer. Large prostate volume and short tumor length on biopsy remained as independent predictors in multivariate analysis. CONCLUSIONS: Favorable features of biopsy often are followed by adverse pathologic findings on prostatectomy specimens despite fulfilling the established criteria. The finding that prostate volume is important does not simply mirror many other studies showing PSAD is important, and the clinical criteria for risk assessment before definitive therapy or active surveillance should incorporate these significant factors other than clinical T-staging or PSAD to minimize under-estimation of cancer in Japanese patients with low-risk PCa.

The Development of IgE Multiple Myeloma Following Treatment for Locally Advanced Prostate Cancer.

This case report documents the diagnosis of multiple myeloma (MM) in a 74-year-old man following treatment for locally advanced prostate cancer. It is important to include MM in the differential diagnosis when the patient presents with nonspecific symptoms such as back pain, anemia, and renal impairment in the absence of a prominent increase in prostate-specific antigen (PSA). The present case was diagnosed as IgE MM with a poor prognosis. Prompt diagnosis and intervention of MM is necessary to avoid complications, including renal impairment.

Increased expression of system large amino acid transporter (LAT)-1 mRNA is associated with invasive potential and unfavorable prognosis of human clear cell renal cell carcinoma.

BACKGROUND: The system L amino acid transporter (LAT) has an important role in the transport of various amino acids, and there have been reports about the relation of this system to cancer. Although LATs are highly expressed in the kidneys, little is known about their influence on human renal cancer. METHODS: To clarify the role of LATs in human clear cell renal cell carcinoma (RCC), we investigated the expression of mRNAs for LAT1, LAT2, LAT3, LAT4, and 4F2hc in clear cell RCC tissues. The mRNAs of these five genes were analyzed by the real-time reverse transcription polymerase chain reaction in matched sets of tumor and non-tumor tissues obtained at operation from 82 Japanese patients with clear cell RCC. We also measured phosphorylated S6 ribosomal protein (Ser-235/236) proteins levels in 18 paired tumor and non-tumor tissues of the patients by Western blotting. RESULTS: Expression of LAT1 mRNA was significantly increased in tumor tissue compared with non-tumor tissue, while expression of LAT2 and LAT3 mRNAs was reduced. There was no difference in the expression of LAT4 and 4F2hc mRNAs between tumor and non-tumor tissues. Increased expression of LAT1 mRNA was associated with less differentiated tumors, local invasion, microscopic vascular invasion, and metastasis. Kaplan-Meier survival analysis showed that a higher serum LAT1 mRNA level was associated with a shorter overall survival time. Phosphorylated S6 ribosomal protein levels were associated with metastatic potential. LAT1 mRNA levels positively correlated with phosphorylated S6 ribosomal protein proteins levels in primary tumors. CONCLUSIONS: These findings suggest that LAT1 mRNA is related to the invasive and progressive potential of clear cell RCC.

Renal metanephric adenoma mimicking papillary renal cell carcinoma on computed tomography: a case report.

We present a case of renal metanephric adenoma (MA) mimicking papillary renal cell carcinoma (PRCC) on computed tomography (CT). In the present case, double-phase enhanced CT showed a hypovascular right renal tumor with gradual and prolonged enhancement. The renal tumor was surgically removed. Histological examination of the resected specimen showed renal MA. Although the radiological features of renal MA have been described by some authors, only a few reports have mentioned the pattern of enhancement on multiphase enhanced CT. The pattern of enhancement of a renal tumor is likely to be correlated with its pathological features. Since renal MA is thought to be genetically related to PRCC, these two tumors are likely to demonstrate similar radiological features, so that differentiating between them becomes difficult. In patients with a hypovascular renal mass that shows gradual and prolonged enhancement on multiphase enhanced CT, the diagnosis of renal MA should be considered.

Intravesical Infection Stones Caused by Magnetic Beads.

The presence of an intravesical foreign body is a rare condition concerning the diseases of the urinary system. Intravesical foreign bodies may cause hematuria and bladder perforation, which are difficult to diagnose and treat. There are various types of foreign bodies in the bladder; however, magnetic beads are rare. Multiple beads may be inserted into the urethra. A few small magnetic beads may be removed from the urethra, but an open removal is an option for many or large beads because of calculus adherence. This case reports the successful open removal of 57 magnetic beads with calculus adherence.

Serum interferon alpha receptor 2 mRNA may predict efficacy of interferon alpha with/without low-dose sorafenib for metastatic clear cell renal cell carcinoma.

BACKGROUND: Interferon (IFN) alpha is one of the central agents in immunotherapy for renal cell carcinoma (RCC). It acts by binding to the IFN-alpha receptor (IFNAR). We previously reported that increased tumor expression of IFNAR2 mRNA was associated with the metastatic potential and progression of RCC, as well as with a poor response of metastatic RCC to IFN-alpha therapy. This study investigated the influence of serum IFNAR2 in RCC patients. METHODS: We measured serum IFNAR2 mRNA levels and quantified IFNAR mRNA expression in paired tumor and non-tumor tissues from the surgical specimens of 66 consecutive RCC patients by the real-time reverse transcription polymerase chain reaction (RT-PCR). We also measured phosphorylated Akt (Ser-473) and phosphorylated-S6 ribosomal protein (Ser-235/236) proteins levels in paired tumor and non-tumor tissues of patients with metastatic RCC by Western blotting. RESULTS: The serum level of IFNAR2 mRNA was not associated with its tumor tissue level. Serum IFNAR2 mRNA was positively correlated with tumor size (P < 0.05), but not with tumor grade, pT stage, metastasis, microscopic vascular invasion, or serum C-reactive protein. Serum levels of IFNAR2 mRNA were significantly higher in patients with a good response to IFN-alpha ± sorafenib than in those with a poor response (P < 0.0001). Tumor tissue IFNAR2 mRNA levels and phosphorylated-S6 ribosomal protein (Ser-235/236) levels were associated with metastatic potential (P < 0.001 and P < 0.01, respectively), and patients with a low IFNAR2 mRNA level and low phosphorylated Akt (Ser-473) protein level in the primary tumor showed a good response to IFN-α ± sorafenib (IFN-α ± Sor: CR-PR) (P < 0.01 and P < 0.05, respectively). Kaplan-Meier survival analysis showed that a higher serum IFNAR2 mRNA level was associated with longer overall survival of treated patients (P < 0.05), while a higher tumor tissue IFNAR2 mRNA level was related to shorter overall survival (P < 0.01). CONCLUSIONS: Our findings suggest that a high serum level of IFNAR2 mRNA may be a useful marker for predicting the response of metastatic RCC to IFN-alpha ± sorafenib therapy.

High-resolution soft X-ray photoelectron spectroscopy of liquid water.

High-resolution soft X-ray photoelectron spectra of liquid water (H(2)O and D(2)O) were measured using a liquid beam photoelectron spectrometer. The 1a(1) (O1s) band and the lowest valence 1b(1) band had single peaks, which is not consistent with the split 1b(1)→ 1a(1) of the X-ray emission band of liquid water if the splitting is assumed to originate from level shifts in two different hydrogen bonding structures. The second valence 3a(1) band of liquid water exhibited a flat top implying that two bands exist underneath a broad feature, which is similar to the case of the 3a(1) band of amorphous ice. The energy splitting between the two 3a(1) bands is estimated to be 1.38 eV (H(2)O) and 1.39 eV (D(2)O). Ab initio calculations suggest that the large splitting of the 3a(1) band is characteristic of water molecules that function as both proton donor and acceptor. The overall result is consistent with the conventional model of a tetrahedral hydrogen-bonding network in liquid water.