Origin of Pinning Disorder in Magnetic-Field-Induced Wigner Solids

At low Landau level filling factors (ν), Wigner solid phases of two-dimensional electron systems in GaAs are pinned by disorder and exhibit a pinning mode, whose frequency is a measure of the disorder that pins the Wigner solid. Despite numerous studies spanning the past three decades, the origin of the disorder that causes the pinning and determines the pinning mode frequency remains unknown. Here, we present a study of the pinning mode resonance in the low-ν Wigner solid phases of a series of ultralow-disorder GaAs quantum wells which are similar except for their varying well widths d. The pinning mode frequencies f_{p} decrease strongly as d increases, with the widest well exhibiting f_{p} as low as ≃35  MHz. The amount of reduction of f_{p} with increasing d can be explained remarkably well by tails of the wave function impinging into the alloy-disordered Al_{x}Ga_{1-x}As barriers that contain the electrons. However, it is imperative that the model for the confinement and wave function includes the Coulomb repulsion in the growth direction between the electrons as they occupy the quantum well.

Outcome of Contemporary Nonsurgical Endodontic Retreatment: A Systematic Review of Randomized Controlled Trials and Cohort Studies

INTRODUCTION

The success rates of NS-ReTx have varied across decades of prior research. Nonetheless, recent endodontic advances have substantially enhanced case management. This systematic review aimed to identify rigorous studies on contemporary NS-ReTx, investigating both periapical healing-evaluated strictly for complete resolution or loosely for size reduction of periapical radiolucency-and success, denoting clinical normalcy combined with periapical healing.

METHODS

We systematically searched MEDLINE, Embase, Web of Science, the Cochrane Library, and gray literature from January 1988 to December 2022. Article selection and data extraction were independently conducted by 3 reviewers. Selected studies underwent risk of bias assessment, and evidence quality using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Meta-analysis and meta-regression established pooled outcome rates, 95% confidence intervals (CIs), and significant clinical prognostic factors (P < .05).

RESULTS

Twenty-nine articles were included. Pooled periapical healing rates using strict and loose criteria were 78.8% (95% CI: 75.2-82.4) and 87.5% (95% CI: 83.8-91.2), respectively. Pooled success rates using strict and loose criteria were 78.0% (95% CI: 74.9-81.2) and 86.4% (95% CI: 82.6-90.1), respectively. Meta-regression analyses revealed significant influences on NS-ReTx outcomes (P < .05), including periapical status, lesion size, apical root filling extent, and follow-up duration.

CONCLUSIONS

Contemporary NS-ReTx shows encouraging outcomes, achieving periapical healing and success rates ranging from approximately 78% (strict criteria) to 87% (loose criteria). The absence of or smaller preoperative lesions, adequate root filling length, and extended follow-ups significantly improve NS-ReTx outcomes. Integrating these factors into treatment planning is pivotal for optimizing the outcome of NS-ReTx.

Signatures of Correlated Defects in an Ultraclean Wigner Crystal in the Extreme Quantum Limit

Low-disorder two-dimensional electron systems in the presence of a strong, perpendicular magnetic field terminate at very small Landau level filling factors in a Wigner crystal (WC), where the electrons form an ordered array to minimize the Coulomb repulsion. The nature of this exotic, many-body, quantum phase is yet to be fully understood and experimentally revealed. Here we probe one of WC's most fundamental parameters, namely, the energy gap that determines its low-temperature conductivity, in record mobility, ultrahigh-purity, two-dimensional electrons confined to GaAs quantum wells. The WC domains in these samples contain ≃1000 electrons. The measured gaps are a factor of three larger than previously reported for lower quality samples, and agree remarkably well with values predicted for the lowest-energy, intrinsic, hypercorrelated bubble defects in a WC made of flux-electron composite fermions, rather than bare electrons. The agreement is particularly noteworthy, given that the calculations are done for disorder-free composite fermion WCs, and there are no adjustable parameters. The results reflect the exceptionally high quality of the samples, and suggest that composite fermion WCs are indeed more stable compared to their electron counterparts.

Fractional Quantum Hall State at Filling Factor ν=1/4 in Ultra-High-Quality GaAs Two-Dimensional Hole Systems

Single-component fractional quantum Hall states (FQHSs) at even-denominator filling factors may host non-Abelian quasiparticles that are considered to be building blocks of topological quantum computers. Such states, however, are rarely observed in the lowest-energy Landau level, namely at filling factors ν<1. Here, we report evidence for an even-denominator FQHS at ν=1/4 in ultra-high-quality two-dimensional hole systems confined to modulation-doped GaAs quantum wells. We observe a deep minimum in the longitudinal resistance at ν=1/4, superimposed on a highly insulating background, suggesting a close competition between the ν=1/4 FQHS and the magnetic-field-induced, pinned Wigner solid states. Our experimental observations are consistent with the very recent theoretical calculations that predict that substantial Landau level mixing, caused by the large hole effective mass, can induce composite fermion pairing and lead to a non-Abelian FQHS at ν=1/4. Our results demonstrate that Landau level mixing can provide a very potent means for tuning the interaction between composite fermions and creating new non-Abelian FQHSs.

Moving Crystal Phases of a Quantum Wigner Solid in an Ultra-High-Quality 2D Electron System

In low-disorder, two-dimensional electron systems (2DESs), the fractional quantum Hall states at very small Landau level fillings (ν) terminate in a Wigner solid (WS) phase, where electrons arrange themselves in a periodic array. The WS is typically pinned by the residual disorder sites and manifests an insulating behavior, with nonlinear current-voltage (I-V) and noise characteristics. We report here measurements on an ultralow-disorder, dilute 2DES, confined to a GaAs quantum well. In the ν<1/5 range, superimposed on a highly insulating longitudinal resistance, the 2DES exhibits a developing fractional quantum Hall state at ν=1/7, attesting to its exceptional high quality and dominance of electron-electron interaction in the low filling regime. In the nearby insulating phases, we observe remarkable nonlinear I-V and noise characteristics as a function of increasing current, with current thresholds delineating three distinct phases of the WS: a pinned phase (P1) with very small noise, a second phase (P2) in which dV/dI fluctuates between positive and negative values and is accompanied by very high noise, and a third phase (P3) where dV/dI is nearly constant and small, and noise is about an order of magnitude lower than in P2. In the depinned (P2 and P3) phases, the noise spectrum also reveals well-defined peaks at frequencies that vary linearly with the applied current, suggestive of washboard frequencies. We discuss the data in light of a recent theory that proposes different dynamic phases for a driven WS.

Highly Anisotropic Even-Denominator Fractional Quantum Hall State in an Orbitally Coupled Half-Filled Landau Level

The even-denominator fractional quantum Hall states (FQHSs) in half-filled Landau levels are generally believed to host non-Abelian quasiparticles and be of potential use in topological quantum computing. Of particular interest is the competition and interplay between the even-denominator FQHSs and other ground states, such as anisotropic phases and composite fermion Fermi seas. Here, we report the observation of an even-denominator fractional quantum Hall state with highly anisotropic in-plane transport coefficients at Landau level filling factor ν=3/2. We observe this state in an ultra-high-quality GaAs two-dimensional hole system when a large in-plane magnetic field is applied. By increasing the in-plane field, we observe a sharp transition from an isotropic composite fermion Fermi sea to an anisotropic even-denominator FQHS. Our data and calculations suggest that a unique feature of two-dimensional holes, namely the coupling between heavy-hole and light-hole states, combines different orbital components in the wave function of one Landau level, and leads to the emergence of a highly anisotropic even-denominator fractional quantum Hall state. Our results demonstrate that the GaAs two-dimensional hole system is a unique platform for the exploration of exotic, many-body ground states.

Delocalization and Universality of the Fractional Quantum Hall Plateau-to-Plateau Transitions

Disorder and electron-electron interaction play essential roles in the physics of electron systems in condensed matter. In two-dimensional, quantum Hall systems, extensive studies of disorder-induced localization have led to the emergence of a scaling picture with a single extended state, characterized by a power-law divergence of the localization length in the zero-temperature limit. Experimentally, scaling has been investigated via measuring the temperature dependence of plateau-to-plateau transitions between the integer quantum Hall states (IQHSs), yielding a critical exponent κ≃0.42. Here we report scaling measurements in the fractional quantum Hall state (FQHS) regime where interaction plays a dominant role. Our Letter is partly motivated by recent calculations, based on the composite fermion theory, that suggest identical critical exponents in both IQHS and FQHS cases to the extent that the interaction between composite fermions is negligible. The samples used in our experiments are two-dimensional electron systems confined to GaAs quantum wells of exceptionally high quality. We find that κ varies for transitions between different FQHSs observed on the flanks of Landau level filling factor ν=1/2 and has a value close to that reported for the IQHS transitions only for a limited number of transitions between high-order FQHSs with intermediate strength. We discuss possible origins of the nonuniversal κ observed in our experiments.

Valley-Tunable Even-Denominator Fractional Quantum Hall State in the Lowest Landau Level of an Anisotropic System

Fractional quantum Hall states (FQHSs) at even-denominator Landau level filling factors (ν) are of prime interest as they are predicted to host exotic, topological states of matter. We report here the observation of a FQHS at ν=1/2 in a two-dimensional electron system of exceptionally high quality, confined to a wide AlAs quantum well, where the electrons can occupy multiple conduction-band valleys with an anisotropic effective mass. The anisotropy and multivalley degree of freedom offer an unprecedented tunability of the ν=1/2 FQHS as we can control both the valley occupancy via the application of in-plane strain, and the ratio between the strengths of the short- and long-range Coulomb interaction by tilting the sample in the magnetic field to change the electron charge distribution. Thanks to this tunability, we observe phase transitions from a compressible Fermi liquid to an incompressible FQHS and then to an insulating phase as a function of tilt angle. We find that this evolution and the energy gap of the ν=1/2 FQHS depend strongly on valley occupancy.

Robust Quantum Hall Ferromagnetism near a Gate-Tuned ν=1 Landau Level Crossing

In a low-disorder two-dimensional electron system, when two Landau levels of opposite spin or pseudospin cross at the Fermi level, the dominance of the exchange energy can lead to a ferromagnetic, quantum Hall ground state whose gap is determined by the exchange energy and has skyrmions as its excitations. This is normally achieved via applying either hydrostatic pressure or uniaxial strain. We study here a very high-quality, low-density, two-dimensional hole system, confined to a 30-nm-wide (001) GaAs quantum well, in which the two lowest-energy Landau levels can be gate tuned to cross at and near filling factor ν=1. As we tune the field position of the crossing from one side of ν=1 to the other by changing the hole density, the energy gap for the quantum Hall state at ν=1 remains exceptionally large, and only shows a small dip near the crossing. The gap overall follows a sqrt[B] dependence, expected for the exchange energy. Our data are consistent with a robust quantum Hall ferromagnet as the ground state.

Even-Denominator Fractional Quantum Hall State at Filling Factor ν=3/4

Fractional quantum Hall states (FQHSs) exemplify exotic phases of low-disorder two-dimensional (2D) electron systems when electron-electron interaction dominates over the thermal and kinetic energies. Particularly intriguing among the FQHSs are those observed at even-denominator Landau level filling factors, as their quasiparticles are generally believed to obey non-Abelian statistics and be of potential use in topological quantum computing. Such states, however, are very rare and fragile, and are typically observed in the excited Landau level of 2D electron systems with the lowest amount of disorder. Here we report the observation of a new and unexpected even-denominator FQHS at filling factor ν=3/4 in a GaAs 2D hole system with an exceptionally high quality (mobility). Our magnetotransport measurements reveal a strong minimum in the longitudinal resistance at ν=3/4, accompanied by a developing Hall plateau centered at (h/e^{2})/(3/4). This even-denominator FQHS is very unusual as it is observed in the lowest Landau level and in a 2D hole system. While its origin is unclear, it is likely a non-Abelian state, emerging from the residual interaction between composite fermions.

Anisotropic Two-Dimensional Disordered Wigner Solid

The interplay between the Fermi sea anisotropy, electron-electron interaction, and localization phenomena can give rise to exotic many-body phases. An exciting example is an anisotropic two-dimensional (2D) Wigner solid (WS), where electrons form an ordered array with an anisotropic lattice structure. Such a state has eluded experiments up to now as its realization is extremely demanding: First, a WS entails very low densities where the Coulomb interaction dominates over the kinetic (Fermi) energy. Attaining such low densities while keeping the disorder low is very challenging. Second, the low-density requirement has to be fulfilled in a material that hosts an anisotropic Fermi sea. Here, we report transport measurements in a clean (low-disorder) 2D electron system with anisotropic effective mass and Fermi sea. The data reveal that at extremely low electron densities, when the r_{s} parameter, the ratio of the Coulomb to the Fermi energy, exceeds ≃38, the current-voltage characteristics become strongly nonlinear at small dc biases. Several key features of the nonlinear characteristics, including their anisotropic voltage thresholds, are consistent with the formation of a disordered, anisotropic WS pinned by the ubiquitous disorder potential.

Spontaneous Valley Polarization of Itinerant Electrons

Memory or transistor devices based on an electron's spin rather than its charge degree of freedom offer certain distinct advantages and comprise a cornerstone of spintronics. Recent years have witnessed the emergence of a new field, valleytronics, which seeks to exploit an electron's valley index rather than its spin. An important component in this quest would be the ability to control the valley index in a convenient fashion. Here we show that the valley polarization can be switched from zero to 1 by a small reduction in density, simply tuned by a gate bias, in a two-dimensional electron system. This phenomenon, which is akin to Bloch spin ferromagnetism, arises fundamentally as a result of electron-electron interaction in an itinerant, dilute electron system. Essentially, the kinetic energy favors an equal distribution of electrons over the available valleys, whereas the interaction between electrons prefers single-valley occupancy below a critical density. The gate-bias-tuned transition we observe is accompanied by a sudden, twofold change in sample resistance, making the phenomenon of interest for potential valleytronic transistor device applications. Our observation constitutes a quintessential demonstration of valleytronics in a very simple experiment.

Fractional Quantum Hall Effect Energy Gaps: Role of Electron Layer Thickness

The fractional quantum Hall effect stands as a quintessential manifestation of an interacting two-dimensional electron system. One of the fractional quantum Hall effect's most fundamental characteristics is the energy gap separating the incompressible ground state from its excitations. Yet, despite nearly four decades of investigations, a quantitative agreement between the theoretically calculated and experimentally measured energy gaps is lacking. Here we report a systematic experimental study that incorporates very high-quality two-dimensional electron systems confined to GaAs quantum wells with fixed density and varying well widths. The results demonstrate a clear decrease of the energy gap as the electron layer is made thicker and the short-range component of the Coulomb interaction is weakened. We also provide a quantitative comparison between the measured energy gaps and the available theoretical calculations that takes into account the role of finite layer thickness and Landau level mixing. All the measured energy gaps fall below the calculations, but as the electron layer thickness increases, the results of experiments and calculations come closer. Accounting for the role of disorder in a phenomenological manner, we find better overall agreement between the measured and calculated energy gaps, although some puzzling discrepancies remain.

Updates on Therapeutic Alternatives for Genitourinary Syndrome of Menopause: Hormonal and Non-Hormonal Managements

Postmenopausal atrophic vaginitis, along with vasomotor symptoms and sleep disorders, is one of the most troublesome symptoms of menopause. However, many women do not manage this symptom properly due to insufficient knowledge of the symptoms or sexual embarrassment. With appropriate treatment, many postmenopausal women can experience relief from discomforts, including burning sensation or dryness of the vagina and dyspareunia. Topical lubricants and moisturizers, systemic and local estrogens, testosterones, intravaginal dehydroepiandrosterones (DHEAs), selective estrogen receptor modulators, and energy-based therapies are possible treatment modalities. Systemic and local estrogen therapies effectively treat genitourinary syndrome of menopause (GSM), but they are contraindicated in patients with breast cancer, for whom lubricants and moisturizers must be considered as the primary treatment. Intravaginal DHEA and ospemifene can be recommended for moderate to severe GSM; however, there is insufficient data on the use of intravaginal DHEA or ospemifene in patients with breast cancer, and further studies are needed. Energy-based devices such as vaginal laser therapy reportedly alleviate GSM symptoms; however, the U.S. Food and Drug Administration warning has recently been issued because of complications such as chronic pain and burning sensations of the vagina. To summarize, clinicians should provide appropriate individualized treatment options depending on women's past history, symptom severity, and chief complaints.

Observation of spontaneous ferromagnetism in a two-dimensional electron system

What are the ground states of an interacting, low-density electron system? In the absence of disorder, it has long been expected that as the electron density is lowered, the exchange energy gained by aligning the electron spins should exceed the enhancement in the kinetic (Fermi) energy, leading to a (Bloch) ferromagnetic transition. At even lower densities, another transition to a (Wigner) solid, an ordered array of electrons, should occur. Experimental access to these regimes, however, has been limited because of the absence of a material platform that supports an electron system with very high quality (low disorder) and low density simultaneously. Here we explore the ground states of interacting electrons in an exceptionally clean, two-dimensional electron system confined to a modulation-doped AlAs quantum well. The large electron effective mass in this system allows us to reach very large values of the interaction parameter [Formula: see text], defined as the ratio of the Coulomb to Fermi energies. As we lower the electron density via gate bias, we find a sequence of phases, qualitatively consistent with the above scenario: a paramagnetic phase at large densities, a spontaneous transition to a ferromagnetic state when [Formula: see text] surpasses 35, and then a phase with strongly nonlinear current-voltage characteristics, suggestive of a pinned Wigner solid, when [Formula: see text] exceeds [Formula: see text] However, our sample makes a transition to an insulating state at [Formula: see text], preceding the onset of the spontaneous ferromagnetism, implying that besides interaction, the role of disorder must also be taken into account in understanding the different phases of a realistic dilute electron system.

Precise Experimental Test of the Luttinger Theorem and Particle-Hole Symmetry for a Strongly Correlated Fermionic System

A fundamental concept in physics is the Fermi surface, the constant-energy surface in momentum space encompassing all the occupied quantum states at absolute zero temperature. In 1960, Luttinger postulated that the area enclosed by the Fermi surface should remain unaffected even when electron-electron interaction is turned on, so long as the interaction does not cause a phase transition. Understanding what determines the Fermi surface size is a crucial and yet unsolved problem in strongly interacting systems such as high-T_{c} superconductors. Here we present a precise test of the Luttinger theorem for a two-dimensional Fermi liquid system where the exotic quasiparticles themselves emerge from the strong interaction, namely, for the Fermi sea of composite fermions (CFs). Via direct, geometric resonance measurements of the CFs' Fermi wave vector down to very low electron densities, we show that the Luttinger theorem is obeyed over a significant range of interaction strengths, in the sense that the Fermi sea area is determined by the density of the minority carriers in the lowest Landau level. Our data also address the ongoing debates on whether or not CFs obey particle-hole symmetry, and if they are Dirac particles. We find that particle-hole symmetry is obeyed, but the measured Fermi sea area differs quantitatively from that predicted by the Dirac model for CFs.

Thermal and Quantum Melting Phase Diagrams for a Magnetic-Field-Induced Wigner Solid

A sufficiently large perpendicular magnetic field quenches the kinetic (Fermi) energy of an interacting two-dimensional (2D) system of fermions, making them susceptible to the formation of a Wigner solid (WS) phase in which the charged carriers organize themselves in a periodic array in order to minimize their Coulomb repulsion energy. In low-disorder 2D electron systems confined to modulation-doped GaAs heterostructures, signatures of a magnetic-field-induced WS appear at low temperatures and very small Landau level filling factors (ν≃1/5). In dilute GaAs 2D hole systems, on the other hand, thanks to the larger hole effective mass and the ensuing Landau level mixing, the WS forms at relatively higher fillings (ν≃1/3). Here we report our measurements of the fundamental temperature vs filling phase diagram for the 2D holes' WS-liquid thermal melting. Moreover, via changing the 2D hole density, we also probe their Landau level mixing vs filling WS-liquid quantum melting phase diagram. We find our data to be in good agreement with the results of very recent calculations, although intriguing subtleties remain.

Unconventional Anisotropic Even-Denominator Fractional Quantum Hall State in a System with Mass Anisotropy

The fractional quantum Hall state (FQHS) observed at a half-filled Landau level in an interacting two-dimensional electron system (2DES) is among the most exotic states of matter as its quasiparticles are expected to be Majorana excitations with non-Abelian statistics. We demonstrate here the unexpected presence of such a state in a novel 2DES with a strong band-mass anisotropy. The FQHS we observe has unusual characteristics. While its Hall resistance is well quantized at low temperatures, it exhibits highly anisotropic in-plane transport resembling compressible stripe or nematic charge-density-wave phases. More striking, the anisotropy sets in suddenly below a critical temperature, suggesting a finite-temperature phase transition. Our observations highlight how anisotropy modifies the many-body phases of a 2DES, and should further fuel the discussion surrounding the enigmatic even-denominator FQHS.

Müllerian inhibiting substance/anti-Müllerian hormone type II receptor protein and mRNA expression in the healthy and cancerous endometria

Müllerian inhibiting substance/anti-Müllerian hormone (MIS/AMH) is a regulator of the female reproductive system, an indicator of ovarian reserve and a growth inhibitor of Müllerian duct-derived tumors in vivo and in vitro. The objective of the present study was to analyze MIS/AMH type II receptor (MIS/AMHRII) protein and mRNA expression in healthy human endometria compared with patients with endometrial hyperplasia and endometrial cancer, providing a foundation for MIS/AMH as a biological modifier for treatment of endometrial hyperplasia and endometrial cancer. The present study included healthy endometrial tissues (n=20), simple endometrial hyperplasia tissues without atypia (n=17), complex endometrial hyperplasia tissues without atypia (n=24) and endometrial cancer tissues (n=8). The location and variation of MIS/AMHRII protein expression was observed by immunohistochemistry. The expression was graded by two pathologists and was categorized as follows: Negative, weakly positive, moderately positive or strongly positive. Reverse transcription-quantitative polymerase chain reaction was used to quantify MIS/AMHRII mRNA expression. The expression of MIS/AMHRII protein was observed in the cytoplasm of healthy human endometria, endometrial hyperplasia and endometrial cancer cells. The frequency of MIS/AMHRII protein expression was 20.22±10.35% in the proliferative phase of the healthy endometrium and 24.09±11.73% in the secretory phase of the healthy endometrium. However, no differences were observed in the menstrual cycle phases. The frequency was 54.50±16.59% in endometrial hyperplasia without atypia, 55.10±15.87% in endometrial hyperplasia with atypia and 73.88±15.70% in endometrial cancer, indicating that expression was enhanced as the disease progressed from healthy to malignant status. In endometrial hyperplasia, MIS/AMHRII protein expression was significantly associated with histological complexity compared with atypia status. The present study demonstrated that MIS/AMHRII is present in healthy endometria, endometrial hyperplasia and endometrial cancer. The low expression frequency of MIS/AMHRII was not significantly different among normal endometrial tissues, however, the protein expression was elevated in endometrial hyperplasia and endometrial cancer. These findings indicated that the study of bioactive MIS/AMH, as a possible treatment for tumors expressing the MIS/AMH receptor, is essential.

Expression of Müllerian-Inhibiting Substance/Anti-Müllerian Hormone Type II Receptor in the Human Theca Cells

CONTEXT

Müllerian-inhibiting substance/anti-Müllerian hormone (MIS/AMH) is produced in the ovarian granulosa cells, and it is believed to inhibit ovarian folliculogenesis and steroidogenesis in women of reproductive age.

OBJECTIVE

To investigate the expression of MIS/AMH type II receptor (MISRII/AMHRII) that binds MIS/AMH in the ovaries of reproductive-age women; to identify the exact targets of MIS/AMH.

DESIGN

Laboratory study using human ovarian tissue.

SETTING

University hospital.

PATIENTS

Tissue samples from 25 patients who had undergone ovarian surgery.

INTERVENTIONS

The segregation of ovarian granulosa and theca cells by laser microdissection was followed by RT-PCR, analyzing MISRII/AMHRII mRNA expression. Afterward, in situ hybridization and immunohistochemistry were performed to determine the localization of MISRII/AMHRII mRNA and protein expression.

MAIN OUTCOME MEASURES

MISRII/AMHRII mRNA expression by RT-PCR, in situ hybridization, and immunohistochemistry.

RESULTS

MISRII/AMHRII were expressed in granulosa and theca cells of preantral and antral follicles. The granulosa cells showed stronger MISRII/AMHRII expression than theca cells. MISRII/AMHRII mRNA staining of granulosa and theca cells in large antral follicles, early atretic follicles, and corpus luteum waned but were still detected weakly, showing higher expression in theca cells than in granulosa cells. However, MISRII/AMHRII protein in the granulosa layer of the atretic follicle and corpus luteum could not be assessed.

CONCLUSIONS

As MISRII/AMHRII is expressed in both granulosa and theca cells, this indicates that MIS/AMH, produced in the granulosa cells, is active in the theca cells as well. MIS/AMH is most likely actively involved not only in the autocrine and endocrine processes but also in the paracrine processes involving theca cells.

Early Vs Late Liver Retransplantation: Different Characteristics and Prognostic Factors

BACKGROUND

East Asia is a known endemic area for hepatitis B, and living donor liver transplantation is mainly performed. Liver retransplantation (ReLT) is expected to become an increasing problem because of a shortage of organs. This study aimed to compare early and late ReLT with consideration of specific circumstances and disease background of East Asians.

METHODS

Between October 1996 and January 2015, 51 patients underwent ReLT; we performed a retrospective analysis of data obtained from medical records of the patients. Clinical characteristics, indication, causes of death, survival rate, and prognostic factors were investigated.

RESULT

The survival rate for early ReLT (n = 18) was 51.5% and that for late ReLT (n = 33) was 50.1% at 1 year postoperatively. Continuous venovenous hemodialysis and the use of mechanical ventilators were more frequent, and pre-retransplant intensive care unit stay and prothrombin time was longer in early ReLT than in late ReLT. Operation time was longer and the amount of intraoperative blood loss was greater in late ReLT than in early ReLT. Multivariate analysis showed that a higher C-reactive protein level increased mortality in early ReLT (P = .045), whereas a higher total bilirubin level increased the risk of death in late ReLT (P = .03).

CONCLUSION

Patients with early ReLT are likely to be sicker pre-retransplantation and require adequate treatment of the pretransplant infectious disease. On the other hand, late ReLT is likely to be technically more difficult and should be decided before the total bilirubin level increases substantially.

Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012

BACKGROUND

Menstrual irregularity is an indicator of endocrine disorders and reproductive health status. It is associated with various diseases and medical conditions, including obesity and underweight. We aimed to assess the association between body weight changes and menstrual irregularity in Korean women.

METHODS

A total of 4,621 women 19 to 54 years of age who participated in the 2010 to 2012 Korea National Health and Nutrition Examination Survey were included in this study. Self-reported questionnaires were used to collect medical information assessing menstrual health status and body weight changes. Odds ratios (ORs) and 95% confidence interval (CI) were calculated to evaluate the association between body weight changes and menstrual irregularity.

RESULTS

Significantly higher ORs (95% CI) were observed in the association between menstrual irregularity and both weight loss (OR, 1.74; 95% CI, 1.22 to 2.48) and weight gain (OR, 1.45; 95% CI, 1.13 to 1.86) after adjusting for age, body mass index, current smoking, heavy alcohol drinking, regular exercise, calorie intake, education, income, metabolic syndrome, age of menarche, parity, and stress perception. Of note, significant associations were only observed in subjects with obesity and abdominal obesity, but not in non-obese or non-abdominally obese subjects. U-shaped patterns were demonstrated in both obese and abdominally obese subjects, indicating that greater changes in body weight are associated with higher odds of menstrual irregularity.

CONCLUSION

We found a U-shaped pattern of association between body weight changes and menstrual irregularity among obese women in the general Korean population. This result indicates that not only proper weight management but also changes in body weight may influence the regulation of the menstrual cycle.

Robot-Assisted Laparoscopic Adenomyomectomy for Patients Who Want to Preserve Fertility

An adenomyomectomy is a conservative-surgical option for preserving fertility. Conventional laparoscopic adenomyomectomies present difficulties in adenomyoma removal and suturing of the remaining myometrium. Robot-assisted laparoscopic surgery could overcome the limitations of conventional laparoscopic surgery. Four patients with severe secondary dysmenorrhea and pelvic pain visited Seoul St. Mary's Hospital and were diagnosed with adenomyosis by pelvic ultrasonography and pelvic magnetic resonance imaging (MRI). The four patients were unmarried, nulliparous women, who desired a fertility-preserving treatment. We performed robot-assisted laparoscopic adenomyomectomies. The dysmenorrhea and pelvic pain of the patients nearly disappeared after surgery. No residual adenomyosis was observed on the follow-up pelvic MRI. A robot-assisted laparoscopic adenomyomectomy was feasible, and could be a minimally invasive surgical option for fertility-sparing treatment in patients with adenomyosis.

Transcriptome analysis reveals that Müllerian inhibiting substance regulates signaling pathways that contribute to endometrial carcinogenesis

Müllerian inhibiting substance (MIS) has been shown to inhibit growth of a number of tumors in vitro and/or in vivo, but the downstream pathways which it regulates are not fully understood. In the present study we show that MIS type II receptor was highly expressed in AN3CA cells, a cell line derived from human endometrial cancer cell in which MIS-treatment caused a reduction of cell viability, and induced cellular apoptosis and genes involved cell cycle arrest. To understand the genome-wide effects of MIS on gene regulation, we performed serial gene expression analyses from 0 to 96 h at 24 h intervals after treating AN3CA cells with MIS. Transcriptomic analysis of molecular changes induced by MIS identified 2,688 differentially expressed genes that were significantly up- or down-regulated during the 96 h study period. When the 2,688 differentially expressed genes were mapped to known biological processes, Wnt-, cancer-, proteolysis-, cytoskeleton-, cell cycle-, apoptosis-, and MAPK-signaling pathways emerged as the functions most significantly changed by MIS in AN3CA cells. Furthermore, western blot analysis validated that protein expression of cell cycle inhibitory genes, apoptotic protease activating factor-1 (APAF-1), β-catenin-interacting protein (ICAT), Rb related protein 130 (p130), and inhibitor of disheveled Dvl and Axin complex (IDAX), were gradually increased over the time of the study, whereas downstream cell cycle activating genes, cyclin-dependent kinase 2 (CDK2) and phospho-c-Jun were downregulated in MIS-treated AN3CA cells. These transcriptome analyses support previous observations that MIS functions as a tumor suppressor, potentially by regulating signaling pathways that could contribute to endometrial carcinogenesis, and indicating that MIS should be considered as a potential treatment for endometrial cancer.

A health risk assessment of reclaimed municipal wastewater for industrial and miscellaneous use

The study evaluated the safety of reclaimed water using health risk assessment and biotoxicity tests. The reclaimed water was produced from reverse osmosis and used in industrial and miscellaneous purposes. The health risk assessment was conducted based on the concentrations of detectable pollutants in reclaimed water in a hypothetical scenario. The estimated carcinogenic and non-carcinogenic risks are lower than the generally accepted level. Biotoxicity evaluation included three genotoxicity tests, a chronic toxicity test using medaka fishes, and a subchronic toxicity test using mice. The reclaimed water is not genetically toxic, and does not cause significant chronic effects on these model organisms. These results confirm the safety of using reclaimed water from municipal wastewater treatment plants.

Application of scientific criteria to food allergens of public health importance

Scientific criteria for identifying allergenic foods of public health importance (Björkstén, B., Crevel, R., Hischenhuber, C., Løvik, M., Samuels, F., Strobel, S., Taylor, S.L., Wal, J.-M., Ward, R., 2008. Criteria for identifying allergenic foods of public health importance. Regulatory Toxicology and Pharmacology 51(1), 42-52) have been further refined to incorporate an assessment of the strength of available scientific evidence (van Bilsen, J.H., Ronsmans, S., Crevel, R.W., Rona, R.J., Przyrembel, H., Penninks, A.H., Contor, L., Houben, G.F., 2011. Evaluation of scientific criteria for identifying allergenic food of public health importance. Regulatory Toxicology and Pharmacology 60, 281-289). A multi-disciplinary group was invited to critically test the refined approach. They independently evaluated selected publications on coconut, soy and/or peanut allergy, scored them using the newly developed level of evidence criteria, and debated proposed approaches for combining and utilising the scores to measure the overall impact of an allergen in public health impact assessments. The evaluation of selected publications using the modified criteria produced a relatively consistent result across the experts. These refined criteria were judged to be a way forward for the identification of allergenic foods of public health importance, and for prioritisation of allergen risk management and future data gathering. The debate to combine available evidence when assessing whether an allergenic food is of sufficient public health importance to warrant active management led to proposals on how to weight and combine evidence on allergen severity, potency and prevalence. The refined criteria facilitate a debate to find a meaningful sequence of steps to summarise the available information in relation to a food allergen.

A comparison of the allergic responses induced by Penicillium chrysogenum and house dust mite extracts in a mouse model

A report by the Institute of Medicine suggested that more research is needed to better understand mold effects on allergic disease, particularly asthma development. We compared the ability of the fungal Penicillium chrysogenum (PCE) and house dust mite (HDM) extracts to induce allergic responses in BALB/c mice. The extracts were administered by intratracheal aspiration (IA) at several doses (0, 2.5, 5, 10, 20, 40, and 80 μg) four times over a 4-week period. Three days after the last IA exposure, serum and bronchoalveolar lavage fluid (BALF) were collected. The relative allergenicity of the extracts was evaluated based on the lowest dose able to induce a significant response compared to control (0 μg) and the robustness of the response. PCE induced the most robust response at the lowest dose for most endpoints examined: BALF total, macrophage, neutrophil, and eosinophil cell counts, and antigen-specific IgE. Taken together, our data suggest that PCE may induce a more robust allergic and inflammatory response at lower doses than HDM.

PRACTICAL IMPLICATIONS

Our data suggest that Penicillium chrysogenum is a robust allergen and may be a more potent allergen source than house dust mite (HDM) in this mouse model. Two critical factors in the development of human allergic disease, exposure levels and sensitization thresholds, are unknown for most allergens including molds/fungi. Human exposure levels are not within the scope of this article. However, the data presented suggest a threshold dose for the induction of allergic responsiveness to P. chrysogenum. Additionally, P. chrysogenum as well as other molds may play an important role in asthma development in our society.

Where has the tumor gone? The characteristics of cases of negative pathologic diagnosis after endoscopic mucosal resection

BACKGROUND AND STUDY AIMS

Discrepancies can occur between the histopathological findings from forceps biopsy and endoscopic mucosal resection (EMR), and occasionally in embarrassing cases tumorous tissue is not found at EMR. The aim of the present study was to evaluate the clinical, endoscopic, and histological features of gastric tumors in patients with pathololgically negative findings at EMR.

PATIENTS AND METHODS

We retrospectively reviewed data from all patients with gastric tumor treated with EMR or endoscopic submucosal dissection (ESD) between August 1999 and April 2007 at our institution, and enrolled into the study patients with no tumor tissue found at mucosal resection. Their biopsy and EMR specimen slides were reviewed by a single pathologist. Patient characteristics, including demographic and clinical features, and the endoscopic appearance of mucosal lesions were evaluated.

RESULTS

Out of 633 patients treated with EMR or ESD, 20 patients (3.2 %) were included. The mean +/- SD maximal dimension of the mucosal lesions was 6.40 +/- 2.19 mm (range 3 - 10). Mean number of forceps biopsy fragments was 3.80 +/- 1.96 and mean sampling ratio was 2.08 +/- 1.07 mm/fragment. Before resection, histological findings from forceps biopsy were: 13 low grade dysplasias (65.0 %), 2 high grade dysplasias (10.0 %), and 5 intramucosal carcinomas (25.0 %).

CONCLUSIONS

In the case of pathologically negative findings at EMR, tumors might have been small enough to have been removed by the previous forceps biopsy. However, the possibility of sampling error or of a different location should be considered. Furthermore, appropriate communication between endoscopists and pathologists is essential.

Reclamation of the wastewater from an industrial park using hollow-fibre and spiral-wound membranes: 50 m3 d(-1) pilot testing and cost evaluation

The feasibility of reclaiming effluent from industrial park wastewater treatment plants through a membrane process was evaluated in three phases. In phase 1 we selected nine wastewater treatment plants (WWTPs), each with a design capacity exceeding 10,000 m3 d(-1), and analyzed the corresponding effluent composition. 'Potential recycling percentage', R, ranged from 50% to 80% for the industrial park WWTPs, indicating a high feasibility for the reuse of effluent. In phase 2, a 50 m3 d(-1) pilot plant was installed in one of the selected WWTPs and underwent testing for one year. The quality of the reclaimed water was suitable for general-purpose industrial use. In the two ultrafiltration (UF) modules tested, the hydrophilic polyethersulfone hollow-fibre module was more tolerant to variable properties, and had higher recycling percentages than those of backwashable hydrophobic polyvinylidene difluoride spiral-wound module. Using the spiral-wound UF module helped reduce the cost for producing 1 m3 of reclaimed water (US$0.80) compared with a hollow-fibre module (US$0.88). In phase 3, we evaluated the negative effects of refluxing the reverse osmosis retentate, containing high total dissolved solids and non-biodegradable organics, with the biological treatment unit of the upstream WWTP. Biological compactibility tests showed that the refluxed retentate ratio should be reduced to maintain the conductivity of mixed liquor in the aeration tank at less than 110% of the original value.

Factors related to lymph node metastasis and the feasibility of endoscopic mucosal resection for treating poorly differentiated adenocarcinoma of the stomach

BACKGROUND AND AIM

Endoscopic mucosal resection (EMR) is currently not accepted as an alternative treatment to surgery in early gastric cancer (EGC) of the undifferentiated histologic type. The present retrospective analysis examined the correlation of various histologic factors with the presence of lymph node metastasis (LNM).

PATIENTS AND METHODS

A retrospective analysis on 234 patients with poorly differentiated EGC who underwent radical gastrectomy with D2 lymph node dissection was undertaken. Several clinicopathologic factors were investigated to identify predictive factors for LNM: age, sex, type of operation, tumor location, tumor size, gross type, ulceration, lymphatic invasion, and depth of invasion.

RESULTS

Of the 234 lesions with poorly differentiated EGC, half (n = 116) already showed submucosal invasion in the resection specimen; 25.9 % of those (30/116) were limited to the upper third (SM1). Of the lesions confined to the mucosa, LNM was found in 3.4 % (4/118). With minor submucosal infiltration (SM1), the LNM rate was lower (0/30) in our patient population. Only with SM2/3 infiltration did the LNM rate sharply rise to around 30 %. The cut-off for submucosal infiltration depth was 500 microm (0/32 LNM), above which LNM rates were substantial (31.2 %; 24/77). There was limited correlation between the SM1-3 classification and actual measurement of submucosal infiltration depth. In a multivariate analysis, tumor size ( P = 0.033), depth of invasion ( P = 0.004), and lymphatic invasion ( P < 0.001) were associated with LNM.

CONCLUSION

Poorly differentiated EGC confined to the mucosa or with minimal submucosal infiltration (<or= 500 microm) could be considered for curative EMR due to the low risk of LNM. Given the limited case number of subgroups, these findings should be confirmed by more data from other centers, which should also focus on local recurrence after EMR in poorly differentiated EGC.

Mouse embryonic stem cells that express a NUP98-HOXD13 fusion protein are impaired in their ability to differentiate and can be complemented by BCR-ABL

NUP98-HOXD13 (NHD13) fusions have been identified in patients with myelodysplastic syndrome, acute myelogenous leukemia and chronic myeloid leukemia blast crisis. We generated 'knock-in' mouse embryonic stem (ES) cells that express a NHD13 fusion gene from the endogenous murine NUP98 promoter, and used an in vitro differentiation system to differentiate the ES cells to hematopoietic colonies. Replating assays demonstrated that the partially differentiated NHD13 ES cells were immortal, and two of these cultures were transferred to liquid culture. These cell lines are partially differentiated immature hematopoietic cells, as determined by morphology, immunophenotype and gene expression profile. Despite these characteristics, they were unable to differentiate when exposed to high concentrations of erythropoietin (Epo), granulocyte colony-stimulating factor or macrophage colony-stimulating factor. The cell lines are incompletely transformed, as evidenced by their dependence on interleukin 3 (IL-3), and their failure to initiate tumors when injected into immunodeficient mice. We attempted genetic complementation of the NHD13 gene using IL-3 independence and tumorigenicity in immunodeficient mice as markers of transformation, and found that BCR-ABL successfully transformed the cell lines. These findings support the hypothesis that expression of a NHD13 fusion gene impairs hematopoietic differentiation, and that these cell lines present a model system to study the nature of this impaired differentiation.

Reuse potential analysis on WWTP effluent of industrial parks in Taiwan

This study examined the reuse potential of the effluents discharged from several unified wastewater treatment plants (WWTPs) of industrial parks in Taiwan, with designed capacity exceeding 10,000 CMD. Parameters were selected based on the relevant reuse purposes. The "potential recycling percentage", R of the WWTP effluent was defined as the maximal percentage of pure water extractable by the "ideal reverse osmosis module" while the RO retentate still met local effluent standards and required no treatment. The analytical results demonstrated that the WWTP effluents had potential for recycling. A pilot plant was installed in one of the WWTPs. The treatment process included a sand filter, an ultrafiltration unit (UF) and a reverse osmosis module (RO). Results of this study demonstrated that the production quantity and quality are stable and appropriate for various purposes, including both industrial and domestic applications.

Novel oncogene HCCR: its diagnostic and therapeutic implications for cancer

Identification of robust diagnostic and therapeutic target molecules for human malignancy is still an important issue. If we identify novel proteins which play a stem-line role for cellular transformation or aggravation of malignancy, it could give us a clue to diagnose a tumor in an earlier stage and to develop more reliable therapeutic tools. For this purpose, we have screened abnormally expressed genes in various human cancers by differential display RT-PCR. One of the overexpressed genes was a human cervical cancer oncogene (HCCR). HCCR was not only identified in cervical cancer tissues, but also found to be overexpressed in various human malignancies such as leukemia/lymphoma, breast, kidney, stomach, colon, liver and ovarian cancer. This molecule appeared to be a negative regulator of p53. In this paper, we discuss the biological functions of HCCR molecules and its implications for early diagnosis and future development of therapeutic devices of cancer.

Cellular and molecular mechanisms for immune modulation by deoxynivalenol and other trichothecenes: unraveling a paradox

Macrophages, T cells, and B cells of the immune system are central targets of deoxynivalenol (DON) and other trichothecenes-mycotoxins that can be immunostimulatory or immunosuppressive depending on dose, exposure frequency and timing of functional immune assay. Notably, low dose trichothecene exposure transcriptionally and post-transcriptionally upregulates expression of cytokines, chemokines and inflammatory genes with concurrent immune stimulation, whereas high dose exposure promotes leukocyte apoptosis with concomitant immune suppression. DON and other trichothecenes, via a mechanism known as the ribotoxic stress response, bind to ribosomes and rapidly activate mitogen-activated protein kinases (MAPKs). The latter are important transducers of downstream signaling events related to immune response and apoptosis. Using cloned macrophages, our laboratory has identified two critical upstream transducers of DON-induced MAPK activation. One transducer is double-stranded RNA-(dsRNA)-activated protein kinase (PKR), a widely-expressed serine/theonine protein kinase that can be activated by dsRNA, interferon, and other agents. The second transducer is hematopoetic cell kinase (Hck), a non-receptor associated Src family kinase. Inhibitors and gene silencing studies have revealed that Hck and PKR play roles in DON induced gene expression and apoptosis. Future studies should focus on the molecular linkages between these kinases and trichothecene toxicity.

Modification of the Inhibitory Amino Acid for Epitope Peptide Binding onto Major Histocompatibility Complex Class II Molecules Enhances Immunogenicity of the Antigen

Previously, the arginine at hen egg-white lysozyme 61 (HEL 61) was characterized as inhibiting T-lymphocyte stimulation due to the inefficient binding of the arginine-containing epitope peptide to the corresponding major histocompatibility complex class II molecules in C57BL/6 mice. In this study, we produced recombinant HEL, with arginine or alanine at HEL 61, and compared its ability to induce immune responses in mice to see whether modification of an inhibitory amino acid could enhance the immunogenicity of an inefficient antigen. Immunization of the mice with modified HEL induced strong antibody and T-cell immune responses against the native antigen. The enhanced T-cell immune response was due to a more specific elevation of the T-cell responses to the HEL 46-61 epitope region than to other epitope regions, although recognition of the other epitope peptides of HEL was generally increased. Mass spectrometric analyses of the epitope peptides generated by splenic antigen-presenting cells indicated that production of the epitope peptides encompassing HEL 46-61 was efficient using the modified antigen. These results suggest that modification of the critical amino acid residue(s) involved in hampering induction of an efficient immune response is an effective method to improve the immunogenicity of an inefficient antigen.

Biological nitrogen removal using bio-sorbed internal organic carbon from piggery wastewater in a post-denitrification MLE process

Nitrogen removal from a piggery wastewater was investigated in a post-denitrification modified Lüdzack Ettinger (PDMLE) process. Overall hydraulic retention time (HRT) of the PDMLE, consisting of contact/separator (C/S), nitrification, denitrification and re-aerobic bioreactor was 10 days. 60% of the influent SCOD was separated in the C/S by contacting the return sludge with the synthetic wastewater, however, only 10% of the influent SCOD was separated from the piggery wastewater. Biosorption capacities of the synthetic wastewater and piggery wastewater were 800 and 150 mg/g-MLSS, respectively. In spite of the high organic and nitrogen load, nitrification efficiency was above 95%, and nitrification rate was about 180 mg-NH4+-N/L x day. The removed delta COD/delta nitrate ratios in the denitrification tank were 4.0 and 11.5 g-SCOD/g-nitrate, while denitrification rates were 8.4 and 2.6 mg-nitrate/day for synthetic and piggery wastewater, respectively. In the proposed PDMLE process, both bio-sorbed and bypassed organic matter could be successfully used for nitrate reduction as carbon sources and the final TN removal efficiency was as high as 95%.

Treatment of swine wastewater using MLE process and membrane bio-reactor

The aim of this study was to develop the optimum integrated treatment system for slurry type swine wastewater through field testing. Although composting and liquid composting are the most desirable processes to treat swine wastewater, inadequate composting has been blamed as critical non-point source pollutants. In the area with limited crop land and grass land, the most feasible method to handle slurry type swine wastewater would be that the solids portion from the solids/liquid separation process is treated by composting and then the liquid portion is treated by a series of wastewater treatment processes, including physicochemical treatment system and biological nutrient removal systems such as the modified Ludzack Ettinger (MLE) process and MLE process coupled with a membrane, to satisfy the different effluent criteria. When using the appropriate solids/liquid separation system, the removal efficiency of SS, COD(Cr), and TKN was 92.4%, 73.6%, and 46.0%, respectively and the amount of bulking agent required for composting and organic loading rate for the following wastewater treatment system can be reduced by 94.8% and 84.7%, respectively. When treating the effluent from solids/liquid separation process by MLE process, the optimal volume fraction for denitrification was 20% of total reactor volume and the optimum ratio of F/M and F(N)/M were increased with increase of C/N ratio. Since the effluent quality of MLE process is not enough to discharge, the DAF process was operated with addition of FeCl3 and cationic polyelectrolyte. The effluent from the DAF process was treated in the MLE process coupled with a crossflow ultrafiltration membrane to satisfy more stringent effluent criteria. When external carbon source is added to keep 6.0 of C/N ratio, the efficiency of denitrification is best. The optimum linear velocity and transmembrane pressure for MBR process was 1.8 m/sec and 2.1 atm, respectively. By addition of external carbon source, nitrogen compounds, especially NOx-N, were considerably removed. And by addition of powdered activated carbon, the removal efficiency of COD(Cr) and COD(Mn) and the membrane flux were increased dramatically.

Influence of threonine exporters on threonine production in Escherichia coli

Threonine production in Escherichia coli threonine producer strains is enhanced by overexpression of the E. coli rhtB and rhtC genes or by heterologous overexpression of the gene encoding the Corynebacterium glutamicum threonine excretion carrier, thrE. Both E. coli genes give rise to a threonine-resistant phenotype when overexpressed, and they decrease the accumulation of radioactive metabolites derived from [(14)C] L-threonine. The evidence presented supports the conclusion that both RhtB and RhtC catalyze efflux of L-threonine and other structurally related neutral amino acids, but that the specificities of these two carriers differ substantially.

Nociceptin/orphanin FQ increases ANP secretion in neonatal cardiac myocytes

Nociceptin (N/OFQ) is a novel heptadecapeptide with an amino acid sequence similar to that of endogenous opioid peptide dynorphin A. Dynorphin have been reported to increase the secretion of atrial natriuretic peptide (ANP) via selective activation of kappa-opioid receptor in cultured atrial cardiocytes. The present study was designed to investigate the direct effect of N/OFQ on the ANP secretion in cultured neonatal rat cardiac myocytes via N/OFQ receptor (NOP) activation. The secretion of ANP from cultured neonatal cardiac myocytes was increased in terms of incubation time. N/OFQ, at a dose of 0.3, 1, 3, and 10 microM, caused increases in ANP secretion in a dose-dependent manner. The N/OFQ-induced ANP secretion was completely antagonized by antagonists of NOP, 1 microM each of [Phe1 (CH2-NH) Gly2] nociceptin (1-13)-NH2 ([FG]N/OFQ(1-13)NH2) or naloxone benzoylhydrazone. In contrast, naloxone (1 microM), the non-selective opioid receptor antagonist, did not alter ANP response to N/OFQ. N/OFQ at 3 microM inhibited basal and forskolin-stimulated cAMP production, which was partially antagonized with the pretreatment of [FG]N/OFQ(1-13)NH2. An increase in ANP secretion by N/OFQ was also partially blocked by the pretreatment of forskolin. Homologous competition studies in neonatal cardiomyocyte membranes revealed the presence of two distinct sites. The high affinity site (10.9 +/- 1.6 nM) was far less abundant than the low affinity site. Therefore, these results suggest that N/OFQ causes an increase in ANP secretion in cultured neonatal cardiac myocytes by decreasing cAMP through its binding sites.

Signet ring cell basal cell carcinoma: a basal cell carcinoma with myoepithelial differentiation

Basal cell carcinoma (BCC) can show a variety of routes of differentiation, but myoepithelial differentiation has rarely been described. We describe a case of BCC showing histologic and immunohistochemical features of myoepithelial differentiation. Histologically, the lesion showed well-demarcated tumor nodules composed of two different components. One component was typical of BCC, and the other component was composed of tumor cells containing abundant cytoplasm, eccentric nuclei, and no peripheral palisading, with scattered signet ring-shaped cells. Immunohistochemically, the tumor cells in the typical BCC component stained with CKAE1/AE3 and smooth muscle actin (SMA), but not with S-100 protein. They stained weakly with CAM5.2, epithelial membrane antigen, and glial fibrillary acidic protein (GFAP). The tumor cells in the other component stained strongly with CKAE1/AE3 and SMA, moderately with epithelial membrane antigen and GFAP, and weakly with CAM5.2. In a small area, the tumor cells stained with S-100 protein.

Crystallization of Clonorchis sinensis 26 kDa glutathione S-transferase and its fusion proteins with peptides of different lengths

A Clonorchis sinensis 26 kDa glutathione S-transferase (CsGST) and its fusion proteins containing 14 and 48 amino-acid peptides at the N-terminus have been crystallized using polyethylene glycol monomethylether 550 as a precipitant. Crystals of the three proteins show very similar crystal properties: they diffract to at least 2.3 A resolution and belong to the orthorhombic space group P2(1)2(1)2(1). The unit-cell parameters of CsGST crystals were a = 66.64 (1), b = 68.91 (1), c = 123.41 (2) A, which are very close to those of the crystals of the two fusion proteins. In addition, CsGST fusion proteins containing varying extents of N-terminal-extended peptides are incorporated into a crystal, indicating that the extended peptides have little effect on crystal packing. These results suggest that the crystallization system of CsGST/peptide fusion protein may be generally applicable to obtain crystals of small peptides.

SMR-type multidrug resistance pumps

Multidrug resistance (MDR) efflux pumps in pathogenic microorganisms nullify the effects of antimicrobial drugs used in medicine. We have conducted phylogenetic analyses showing that these efflux pumps are associated with five superfamilies of transport systems. One of these, the drug/metabolite transporter (DMT) superfamily includes a family of small multidrug resistance (SMR)-conferring proteins that are discussed in detail in this review. A single microorganism such as Bacillus subtilis may possess multiple homologs of this family, and these homologs are believed to form both homo-oligomeric or hetero-oligomeric pumps, some of which export cationic drugs. The characteristics of some of these systems and the genes that encode them are described, with emphasis on the eight homologs encoded within the B subtilis genome. Anomalies and unanswered questions that provide impetus for future studies are presented.

Size comparisons among integral membrane transport protein homologues in bacteria, Archaea, and Eucarya

Integral membrane proteins from over 20 ubiquitous families of channels, secondary carriers, and primary active transporters were analyzed for average size differences between homologues from the three domains of life: Bacteria, Archaea, and Eucarya. The results showed that while eucaryotic homologues are consistently larger than their bacterial counterparts, archaeal homologues are significantly smaller. These size differences proved to be due primarily to variations in the sizes of hydrophilic domains localized to the N termini, the C termini, or specific loops between transmembrane alpha-helical spanners, depending on the family. Within the Eucarya domain, plant homologues proved to be substantially smaller than their animal and fungal counterparts. By contrast, extracytoplasmic receptors of ABC-type uptake systems in Archaea proved to be larger on average than those of their bacterial homologues, while cytoplasmic enzymes from different organisms exhibited little or no significant size differences. These observations presumably reflect evolutionary pressure and molecular mechanisms that must have been operative since these groups of organisms diverged from each other.