Changes in spatial self-consciousness elicit grid cell-like representation in the entorhinal cortex

Grid cells in the entorhinal cortex (EC) encode an individual's location in space, integrating both environmental and multisensory bodily cues. Notably, body-derived signals are also primary signals for the sense of self. While studies have demonstrated that continuous application of visuo-tactile bodily stimuli can induce perceptual shifts in self-location, it remains unexplored whether these illusory changes suffice to trigger grid cell-like representation (GCLR) within the EC, and how this compares to GCLR during conventional virtual navigation. To address this, we systematically induced illusory drifts in self-location toward controlled directions using visuo-tactile bodily stimulation, while maintaining the subjects' visual viewpoint fixed (absent conventional virtual navigation). Subsequently, we evaluated the corresponding GCLR in the EC through functional MRI analysis. Our results reveal that illusory changes in perceived self-location (independent of changes in environmental navigation cues) can indeed evoke entorhinal GCLR, correlating in strength with the magnitude of perceived self-location, and characterized by similar grid orientation as during conventional virtual navigation in the same virtual room. These data demonstrate that the same grid-like representation is recruited when navigating based on environmental, mainly visual cues, or when experiencing illusory forward drifts in self-location, driven by perceptual multisensory bodily cues.

Experimentally-evidenced personality alterations following meningioma resection: A case report

Personality changes following neurosurgical procedures remain poorly understood and pose a major concern for patients, rendering a strong need for predictive biomarkers. Here we report a case of a female patient in her 40s who underwent resection of a large sagittal sinus meningioma with bilateral extension, including resection and ligation of the superior sagittal sinus, that resulted in borderline personality disorder. Importantly, we captured clinically-observed personality changes in a series of experiments assessing self-other voice discrimination, one of the experimental markers for self-consciousness. In all experiments, the patient consistently confused self- and other voices - i.e., she misattributed other-voice stimuli to herself and self-voice stimuli to others. Moreover, the electroencephalogram (EEG) microstate, that was in healthy participants observed when hearing their own voice, in this patient occurred for other-voice stimuli. We hypothesize that the patient's personality alterations resulted from a gradual development of a venous collateral hemodynamic network that impacted venous drainage of brain areas associated with self-consciousness. In addition, resection and ligation of the superior sagittal sinus significantly aggravated personality alterations through postoperative decompensation of a direct frontal lobe compression. Experimentally mirroring clinical observations, these findings are of high relevance for developing biomarkers of post-surgical personality alterations.

Image Mapping Accuracy Evaluation Using UAV with Standalone, Differential (RTK), and PPP GNSS Positioning Techniques in an Abandoned Mine Site

Global navigation satellite systems (GNSSs) provide a common positioning method that utilizes satellite signals to determine the spatial location of a receiver. However, there are several error factors in standalone GNSS positioning due to instrumental, procedural, and environmental factors that arise during the signal transmission process, and the final positioning error can be up to several meters or greater in length. Thus, real-time kinematic (RTK) correction and post-mission precise point positioning (PPP) processing technologies are proposed to improve accuracy and accomplish precise position measurements. To evaluate the geolocation accuracy of mosaicked UAV images of an abandoned mine site, we compared each orthomosaic image and digital elevation model obtained using standalone GNSS positioning, differential (RTK) GNSS positioning, and post-mission PPP processing techniques. In the three types of error evaluation measure (i.e., relative camera location error, ground control points-based absolute image mapping error, and volumetric difference of mine tailings), we found that the RTK GNSS positioning method obtained the best performance in terms of the relative camera location error and the absolute image mapping error evaluations, and the PPP post-processing correction effectively reduced the error (69.5% of the average total relative camera location error and 59.3% of the average total absolute image mapping error) relative to the standalone GNSS positioning method. Although differential (RTK) GNSS positioning is widely used in positioning applications that require very high accuracy, post-mission PPP processing can also be used in various fields in which it is either not feasible to operate expensive equipment to receive RTK GNSS signals or network RTK services are unavailable.

Breathing is coupled with voluntary initiation of mental imagery

Previous research has suggested that bodily signals from internal organs are associated with diverse cortical and subcortical processes involved in sensory-motor functions, beyond homeostatic reflexes. For instance, a recent study demonstrated that the preparation and execution of voluntary actions, as well as its underlying neural activity, are coupled with the breathing cycle. In the current study, we investigated whether such breathing-action coupling is limited to voluntary motor action or whether it is also present for mental actions not involving any overt bodily movement. To answer this question, we recorded electroencephalography (EEG), electromyography (EMG), and respiratory signals while participants were conducting a voluntary action paradigm including self-initiated motor execution (ME), motor imagery (MI), and visual imagery (VI) tasks. We observed that the voluntary initiation of ME, MI, and VI are similarly coupled with the respiration phase. In addition, EEG analysis revealed the existence of readiness potential (RP) waveforms in all three tasks (i.e., ME, MI, VI), as well as a coupling between the RP amplitude and the respiratory phase. Our findings show that the voluntary initiation of both imagined and overt action is coupled with respiration, and further suggest that the breathing system is involved in preparatory processes of voluntary action by contributing to the temporal decision of when to initiate the action plan, regardless of whether this culminates in overt movements.

Sense of self impacts spatial navigation and hexadirectional coding in human entorhinal cortex

Grid cells in entorhinal cortex (EC) encode an individual's location in space and rely on environmental cues and self-motion cues derived from the individual's body. Body-derived signals are also primary signals for the sense of self and based on integrated sensorimotor signals (proprioceptive, tactile, visual, motor) that have been shown to enhance self-centered processing. However, it is currently unknown whether such sensorimotor signals that modulate self-centered processing impact grid cells and spatial navigation. Integrating the online manipulation of bodily signals, to modulate self-centered processing, with a spatial navigation task and an fMRI measure to detect grid cell-like representation (GCLR) in humans, we report improved performance in spatial navigation and decreased GCLR in EC. This decrease in entorhinal GCLR was associated with an increase in retrosplenial cortex activity, which was correlated with participants' navigation performance. These data link self-centered processes during spatial navigation to entorhinal and retrosplenial activity and highlight the role of different bodily factors at play when navigating in VR.

Breathing affects self-other voice discrimination in a bodily state associated with somatic passivity

A growing number of studies have focused on identifying cognitive processes that are modulated by interoceptive signals, particularly in relation to the respiratory or cardiac cycle. Considering the fundamental role of interoception in bodily self‐consciousness, we here investigated whether interoceptive signals also impact self‐voice perception. We applied an interactive, robotic paradigm associated with somatic passivity (a bodily state characterized by illusory misattribution of self‐generated touches to someone else) to investigate whether somatic passivity impacts self‐voice perception as a function of concurrent interoceptive signals. Participants' breathing and heartbeat signals were recorded while they performed two self‐voice tasks (self‐other voice discrimination and loudness perception) and while simultaneously experiencing two robotic conditions (somatic passivity condition; control condition). Our data reveal that respiration, but not cardiac activity, affects self‐voice perception: participants were better at discriminating self‐voice from another person’s voice during the inspiration phase of the respiration cycle. Moreover, breathing effects were prominent in participants experiencing somatic passivity and a different task with the same stimuli (i.e., judging the loudness and not identity of the voices) was unaffected by breathing. Combining interoception and voice perception with self‐monitoring framework, these data extend findings on breathing‐dependent changes in perception and cognition to self‐related processing.

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We combined psychophysics with robotics and voice‐morphing technology to evaluate the effect of breathing on self‐voice perception. Our results show that listeners better perceive their own voice during inspiration, an effect that is modulated by self‐related bodily processing. This extends previous findings documenting the effect of interoceptive signals on perception and suggests that the bodily self may serve as a scaffold for cognition.

The perspectives of mapping and monitoring of the sense of self in neurosurgical patients

Surgical treatment of tumors, epileptic foci or of vascular origin, requires a detailed individual pre-surgical workup and intra-operative surveillance of brain functions to minimize the risk of post-surgical neurological deficits and decline of quality of life. Most attention is attributed to language, motor functions, and perception. However, higher cognitive functions such as social cognition, personality, and the sense of self may be affected by brain surgery. To date, the precise localization and the network patterns of brain regions involved in such functions are not yet fully understood, making the assessment of risks of related post-surgical deficits difficult. It is in the interest of neurosurgeons to understand with which neural systems related to selfhood and personality they are interfering during surgery. Recent neuroscience research using virtual reality and clinical observations suggest that the insular cortex, medial prefrontal cortex, and temporo-parietal junction are important components of a neural system dedicated to self-consciousness based on multisensory bodily processing, including exteroceptive and interoceptive cues (bodily self-consciousness (BSC)). Here, we argue that combined extra- and intra-operative approaches using targeted cognitive testing, functional imaging and EEG, virtual reality, combined with multisensory stimulations, may contribute to the assessment of the BSC and related cognitive aspects. Although the usefulness of particular biomarkers, such as cardiac and respiratory signals linked to virtual reality, and of heartbeat evoked potentials as a surrogate marker for intactness of multisensory integration for intra-operative monitoring has to be proved, systemic and automatized testing of BSC in neurosurgical patients will improve future surgical outcome.

Behavioral and neurophysiological evidence for altered interoceptive bodily processing in chronic pain

Whereas impaired multisensory processing of bodily stimuli and distorted body representation are well-established in various chronic pain disorders, such research has focused on exteroceptive bodily cues and neglected bodily signals from the inside of the body (or interoceptive signals). Extending existing basic and clinical research, we investigated for the first time interoception and its neurophysiological correlates in patients with complex regional pain syndrome (CRPS). In three different experiments, including a total of 36 patients with CRPS and 42 aged-gender matched healthy controls, we measured interoceptive sensitivity (heart beat counting task, HBC) and neural responses to heartbeats (heartbeat evoked potentials, HEPs). As hypothesized, we observed reduced sensitivity in perceiving interoceptive bodily stimuli, i.e. their heartbeat, in two independent samples of CRPS patients (studies 1 and 2). Moreover, the cortical processing of their heartbeat, i.e. the HEP, was reduced compared to controls (study 3) and reduced interoceptive sensitivity and HEPs were related to CRPS patients' motor impairment and pain duration. By providing consistent evidence for impaired processing of interoceptive bodily cues in CRPS, this study shows that the perceptual changes occurring in chronic pain include signals originating from the visceral organs, suggesting changes in the neural body representation, that includes next to exteroceptive, also interoceptive bodily signals. By showing that impaired interoceptive processing is associated with clinical symptoms, our findings also encourage the use of interoceptive-related information in future rehabilitation for chronic pain.

Increased heartbeat-evoked potential during REM sleep in nightmare disorder

Nightmares are characterized by the experience of strong negative emotions occurring mainly during REM sleep. Some people suffer from nightmare disorder, which is defined by the repeated occurrence of nightmares and by significant distress in wakefulness. Yet, whether frequent nightmares relate to a general increase in emotional reactivity or arousal during sleep remains unclear. To address this question, we recorded heartbeat-evoked potentials (HEPs) during wakefulness, NREM and REM sleep in patients with nightmare disorder and healthy participants. The HEP represents a cortical (EEG) response to the heartbeat and indexes brain-body interactions, such as interoceptive processing and intrinsic levels of arousal. HEP amplitude is typically increased during states of high emotional arousal and motivation, and is decreased in depression. Here we compared the amplitude of HEPs between nightmare patients and healthy controls separately during AWAKE, NREM, REM periods, and found higher HEP amplitude in nightmare patients compared to healthy controls over a cluster of frontal regions only during REM sleep. This effect was not paralleled by any group difference in cardiac control measures (e.g. heart rate variability, interbeat interval). These findings corroborate the notion that nightmares are essentially a REM pathology and suggest that increased emotional arousal during REM sleep, as measured by HEP, is a physiological condition responsible for frequent nightmares. This result also supports that HEP may be used as a biomarker of increased emotional and sensory processing during REM sleep in these patients.

The neural monitoring of visceral inputs, rather than attention, accounts for first-person perspective in conscious vision

Why should a scientist whose aim is to unravel the neural mechanisms of perception consider brain-body interactions seriously? Brain-body interactions have traditionally been associated with emotion, effort, or stress, but not with the "cold" processes of perception and attention. Here, we review recent experimental evidence suggesting a different picture: the neural monitoring of bodily state, and in particular the neural monitoring of the heart, affects visual perception. The impact of spontaneous fluctuations of neural responses to heartbeats on visual detection is as large as the impact of explicit manipulations of spatial attention in perceptual tasks. However, we propose that the neural monitoring of visceral inputs plays a specific role in conscious perception, distinct from the role of attention. The neural monitoring of organs such as the heart or the gut would generate a subject-centered reference frame, from which the first-person perspective inherent to conscious perception can develop. In this view, conscious perception results from the integration of visual content with first-person perspective.

The neural subjective frame: from bodily signals to perceptual consciousness

The report 'I saw the stimulus' operationally defines visual consciousness, but where does the 'I' come from? To account for the subjective dimension of perceptual experience, we introduce the concept of the neural subjective frame. The neural subjective frame would be based on the constantly updated neural maps of the internal state of the body and constitute a neural referential from which first person experience can be created. We propose to root the neural subjective frame in the neural representation of visceral information which is transmitted through multiple anatomical pathways to a number of target sites, including posterior insula, ventral anterior cingulate cortex, amygdala and somatosensory cortex. We review existing experimental evidence showing that the processing of external stimuli can interact with visceral function. The neural subjective frame is a low-level building block of subjective experience which is not explicitly experienced by itself which is necessary but not sufficient for perceptual experience. It could also underlie other types of subjective experiences such as self-consciousness and emotional feelings. Because the neural subjective frame is tightly linked to homeostatic regulations involved in vigilance, it could also make a link between state and content consciousness.

Sustain and address discharge characteristics of AC-PDP with MgO surface coated by MgO nano crystal powders

This paper examined the sustain and address discharge characteristics of ac-PDPs with MgO surface coated by MgO nano crystal powders. The MgO nano crystal powder was deposited by about 5% on the MgO surface by using the spray method. To investigate the effects of the partial addition of MgO nano crystal powders on the sustain discharge as well as the address discharge, the luminance, IR spectra of 823, 828 nm, cathodoluminance, and firing voltage were measured with the measurement of the address delay times and wall voltage variation in the 42-inch ac-PDP module with a high Xe content of 17%. As a result, the statistical delay characteristics were improved considerably especially under the low panel temperature of -5 degrees C for the MgO surface with MgO nano crystal powder. However, both MgO surfaces with and without the MgO nano crystal powder showed almost similar sustain and address discharge characteristics except the statistical delay characteristics.

Gene expression profiling of a cold-shocked earthworm Eisenia andrei

To identify genes that are modulated under cold-stress conditions in the earthworm Eisenia andrei, we performed a genome-wide analysis of gene expression in cold-shocked earthworms by using Serial Analysis of Gene Expression (SAGE). We identified 5,977 and 5,407 unique SAGE tags under normal and cold-stressed conditions, respectively. The majority of the SAGE tags did not match to any known expressed sequences, due to a paucity of expression data in earthworms. We converted the statistically significant SAGE tags for the cold-stressed condition into expressed sequence tags (ESTs), and the results showed that particular genes associated with energy homeostasis, cellular defense mechanisms, and ion balance were up-regulated or down-regulated. We constructed a regulatory network of some of these genes and identified rps-6 as a core gene in the cold-response regulatory-gene network. Our data provide a baseline for gene expression studies of cold shock in the Lumbricidae.

Pregnancy outcome of women transfused during pregnancy with blood products inadvertently obtained from donors treated with acitretin

We assessed the pregnancy outcome of nine women inadvertently transfused with acitretin-contaminated blood products in South Korea. A total of 18 women matched to cases by age, gravidity, and singleton- or twin-pregnancy, and who were transfused with blood products not contaminated with acitretin, was also recruited. There were nine babies born in the case group. No differences (p > 0.05) were observed between cases and controls in the gestational age at delivery (38.3 +/- 1.6 weeks vs 37.8 +/- 2.2 weeks), birth weight (3,146 +/- 874 g vs 3,106 +/- 568 g), rate of pre-term deliveries (22.2% vs 11.1%) and rate of low birth weight (<2,500 g) (33.3% vs 16.7%). There was no case of malformation or neurological abnormalities born in either group. In conclusion, inadvertent exposure to acitretin-contaminated blood products was not associated with adverse pregnancy outcomes, probably because of the removal of acitretin and etretinate during the manufacturing process of blood products.

PAUF functions in the metastasis of human pancreatic cancer cells and upregulates CXCR4 expression

Pancreatic cancer is characterized by early metastatic spread, but the process of tumor cell dissemination is largely unknown. In this study we show that the soluble protein pancreatic adenocarcinoma upregulated factor (PAUF) has an important role in the metastasis and progression of the disease. Variations in the level of PAUF, either by overexpression or knockdown, resulted in altered migration, invasion and proliferation capacity of pancreatic cancer cells. Moreover, depletion of PAUF in metastatic cells dramatically abrogated the spread of the cells to distant organs in an orthotopic xenograft mouse model. PAUF elicited the activation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and AKT intracellular signaling cascades and consequently their downstream transcription factors in an autocrine manner. Genome-wide expression analysis revealed that C-X-C chemokine receptor type 4 (CXCR4) expression was induced by PAUF overexpression but was repressed by PAUF knockdown. The PAUF-mediated increase in cancer cell motility was attenuated by the CXCR4 inhibitor, AMD3100, or by anti-CXCR4 antibody. Furthermore, immunohistochemical analysis of pancreatic tumor tissues clearly showed a significant positive correlation between PAUF and CXCR4 expression. Collectively, these findings indicate that PAUF enhances the metastatic potential of pancreatic cancer cells, at least in part, by upregulating CXCR4 expression.

Inhibitory effects of antioxidant constituents from Melothria heterophylla on matrix metalloproteinase-1 expression in UVA-irradiated human dermal fibroblasts

Matrix metalloproteinases (MMPs) are known to play an important role in photoaging by mediating the degradation of extracellular matrix proteins. To develop a new anti-aging agent for cosmetics from natural products, Melothria heterophylla (Lour.) Cogn. was selected for its antioxidant activity and inhibitory effect on expression of MMP-1 in UVA-irradiated human skin fibroblasts. Two compounds (compounds 1 and 2 ) were isolated from an ethyl acetate soluble fraction of the ethanolic extracts; they were identified as 1,2,4,6-tetra-O-galloyl-beta-(D)-glucopyranose (1) and 3,4,5-trihydroxybenzoic acid (2). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have SC50 values of 3.9 microM and 13.3 microM against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and values of 4.3 microM and 4.0 microM against superoxide radicals in the xanthine/xanthine oxidase system, respectively. Compounds 1 and 2 showed a dose-dependent inhibitory effect on the expression and activity of MMP-1 in UVA-induced human skin fibroblasts, but no inhibition of MMP-1 mRNA expression. Therefore, we concluded that compounds 1 and 2 significantly inhibited MMP-1 expression at the protein level. Also, these compounds were determined to have a potent antioxidant activity. From these results, we suggest that these compounds might be useful as a new anti-aging agent for photodamaged skin, but the in vitro findings must be verified in in vivo studies.

New cosmetic agents for skin whitening from Angelica dahurica

To develop a new whitening agent for cosmetics from natural products, Angelica dahurica was selected for its inhibitory effect on melanogenesis in B16 melanoma cells. From the mechanism study, it was clarified that the ethanolic extracts of this plant showed the suppression of tyrosinase synthesis but no inhibition of tyrosinase activity. In order to find the active constituents from this plant, the ethanol extracts were chromatographed repeatedly with silica gel. Two coumarin compounds were isolated from A. dahurica. Their structures were identified by physicochemical and spectral data such as UV, IR, NMR, and MS. It was shown that the active substance was isoimperatorin (10-[(3-methyl-2-butenyl)oxy]-7H-furo[3,2-g][1] benzopyran-7-one) and imperatorin (9-[(3-methyl-2-butenyl)oxy]-7H-furo[3,2-g][1] benzopyran-7-one). They significantly inhibited tyrosinase synthesis in B16 melanoma cells. To elucidate the action mechanism of the active compounds of A. dahurica, we investigated the changes in the mRNA level of tyrosinase using the RT-PCR technique. As a result, the mRNA level of tyrosinase was markedly reduced by active compounds of A. dahurica. From these results, we suggest that these extracts might be useful as a new whitening agent in cosmetics, but the in vitro findings must be verified in in vivo skin-lightening studies.

Synthesis and characterization of thermosensitive chitosan copolymer as a novel biomaterial

Novel water-soluble thermosensitive chitosan copolymers were prepared by graft polymerization of N-isopropylacrylamide (NIPAAm) onto chitosan using cerium ammonium nitrate (CAN) as an initiator. The physicochemical properties of the resulting chitosan-g-NIPAAm copolymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, 1H-nuclear magnetic resonance, X-ray diffraction measurement, thermogravimetric analysis (TGA) and solubility test. Sol-gel transition behavior was investigated by the cloud point measurement of the chitosan-g-NIPAAm aqueous solution. The gelling temperature was examined using the vial inversion method. The percentage of grafting (%) and efficiency of grafting (%) were investigated according to concentrations of monomer and initiator. The maximum grafted chitosan copolymer was obtained with 0.4 M NIPAAm and 6 x 10(-3) M CAN. Water-soluble chitosan-g-NIPAAm copolymers were prepared successfully and they formed thermally reversible hydrogel, which exhibits a lower critical solution temperature (LCST) around 32 degrees C in aqueous solutions. A preliminary in vitro cell study showed nontoxic and biocompatible properties. These results suggest that chitosan-g-NIPAAm copolymer could be very useful in biomedical and pharmaceutical applications as an injectable material for cell and drug delivery.

Topography of the outer mandibular symphyseal region with reference to the autogenous bone graft

The mandibular symphysis is preferred as a donor site for the relatively small grafts needed for the autogeneous bone graft procedure. This study was undertaken to determine the morphology and composition of the cortical and trabecular bone in the mandibular symphyseal region using 35 mandible specimens from Koreans. The topographical patterns through the thickness of the cortical plate and the width of the trabecular bone were observed. In this study, the labial cortical plate of the mandible became thicker from the superior to the inferior aspects (P < 0.05). However, the trabecular bone width exhibited a different distribution pattern compared to the thickness of the labial cortical plate. This observation concerning the cortical and trabecular bones assists in determination of the depth of osteotomy. The results provide useful information on the mandibular symphysis graft prior to dental implant placement. These results will enable the volume of the cortical plate in the mandibular symphyseal region and its proper size, depth, and location to be predicted when removing a graft block.

Branching patterns of the facial nerve and its communication with the auriculotemporal nerve

This study examines the anatomic relationships and variability of the facial nerve trunk and its branches, with emphasis on the intraparotid connections between the divisions. Microdissections were performed on 30 Korean half-heads, and the facial nerve trunks and branches were exposed. The average depth of the stylomastoid foramen from the skin surface was 21.0 +/- 3.1 mm, and the distance between the stylomastoid foramen and the bifurcation of the temporofacial (upper) and cervicofacial (lower) divisions was 13.0 +/- 2.8 mm. In 26 of 30 dissections (86.7%), the facial nerve trunk bifurcated into two main divisions, and a trifurcation pattern was seen in the other four cases (13.3%). According to the origin of the buccal branches, we classified the branching patterns of the facial nerve into four categories. In type I (13.8% of cases), the buccal branches arose from the two main divisions of the trunk but not from other branches of the facial nerve. In type II (44.8% of cases), the buccal branches arising from the two main divisions were interconnected with the zygomatic branch. In type III (17.3% of cases), the marginal mandibular branch sent nerve twigs to the buccal branch, which originated from the upper and lower divisions. In type IV (17.3% of cases), the nerve twigs from the zygomatic and marginal mandibular branches merged to the buccal branch arising from the two main divisions. Communications between the facial and auriculotemporal nerve branches, which are known as "communicating auriculotemporal nerves," were observed in 28 of the 30 cases (93.3%). Familiarity with these common variations in the facial anatomy provides useful information for the surgeon in careful dissection, preservation of the facial nerve, and complete removal of the tumors in parotidectomies.

Topographic anatomy of the inferior wall of the maxillary sinus in Koreans

Knowledge of the relationship between the root apex and the inferior wall of the maxillary sinus are crucial for diagnosing and treating a sinus pathosis as well as in assisting in dental implantation. Therefore, identifying the proximity between the root apex and the inferior wall of the sinus and clarifying the cortical thickness of the inferior wall of the sinus is essential for determining the topography of a spreading dental infection into the maxillary sinus. Accordingly, knowledge of the topography between the root apex and the inferior wall of maxillary sinus is important for diagnosing and planning dental implantation, endodontic procedures, and orthodontic treatment. This study was undertaken to clarify the morphological and clinical characteristics of the maxillary sinus, particularly the inferior wall of the sinus in Koreans, and to identify the relationship between the inferior wall of the maxillary sinus and the roots of the maxillary teeth. Twenty-four sides of the maxillae of hemi-sectioned Korean heads were used in this study. All specimens were decalcificated and sectioned coronally. On the sectioned specimens, 21 items were measured using an image analyzing system. The distances between the each root apex and the inferior wall of the maxillary sinus were measured. The distance from the root apex to the inferior wall of the sinus was the shortest in the second molar area and the longest in the first premolar area. The thickness of the cortical plate of the inferior wall of the maxillary sinus was thinnest in the first premolar area but it was thickest in the second premolar area. The vertical relationship between the inferior wall and the roots of the maxillary molars was classified into five types. Type I (the inferior wall of the sinus located above the level connecting the buccal and lingual root apices) dominated (54.5% in the first molar area, 52.4% in the second molar area). The horizontal relationship between the inferior wall of the sinus and the root apex was classified into three types. Type 2 (the alveolar recess of the inferior wall of the sinus was located between the buccal and lingual roots) was most common (80% in the first and second molar area). Overall, this study demonstrated the many anatomical characteristics and determined the relationships between the maxillary sinus and their surrounding structures. These findings may have an impact on the clinical management of patients.

Anatomical study concerning the origin and course of the pectoral branch of the thoracoacromial trunk for the pectoralis major flap

The patterns of the feeding vessels to each muscle determine the extent of their safe transposition and the muscle's value as a pedicled flap in reconstructive surgery. This study aimed to demonstrate the point of origin and the intra- and submuscular course of the pectoral branch of the thoracoacromial trunk (TAT) for pectoralis major (PM) flap surgery. Seventy sides of the PM were dissected based on a clinical reference line that has been used for several decades. The branching point of the TAT from the axillary artery was located lateral to the midclavicular line on the right-sided specimens (100%) and medial to the midclavicular line on the left sides (86%). The branching patterns of the pectoral branch to the PM muscle from the TAT were classified into three types. In type I the pectoral branches originated directly from the TAT (55 cases, 78.6%). In type II (11 cases, 15.7%) and type III (4 cases, 5.7%) the pectoral branch divided from the medial and lateral pedicle of the TAT, respectively. The course of the pectoral branch from the TAT in the PM was categorized into three patterns according to the degree of proximity to the midclavicular line. In 49 cases (70%), the pectoral branch in the PM ran within 1 cm of the midclavicular line. The other cases ran 2 cm (20 cases, 29%) and 3 cm (1 case, 1%) from the midclavicular line, respectively. These results provide topographic data of the pectoral branch based on anatomical landmarks, and will be useful in surgical planning as well as the procedure for PM flap surgery.

The discomallear ligament and the anterior ligament of malleus: An anatomic study in human adults and fetuses

According to some reports, movement of the malleus, resulting from anterior hypertension on the discomallear ligament (DML), could produce aural symptoms related with damage to middle ear structures. The aim of this study was to examine the topographic relationship of the DML and the anterior ligament of malleus (ALM). Four fetuses and 16 adult hemi-sectioned heads were used to determine the anatomic-clinical relevance of DML and ALM in temporomandibular disorder. In fetal specimens, the DML was distinctly interposed between the malleus and the disc of the temporomandibular joint (TMJ), and the ALM had a structure apparently composed of the superior and inferior lamellae, running anteriorly in continuation with the sphenomandibular ligament (SML) through the future petrotympanic fissure (PTF). In all adult specimens, the DML was inserted into the malleus, and it expanded broadly toward the disc and capsular region of the TMJ in a triangular shape and inserted into the disc and capsule of the TMJ. The two-lamellae structure of the ALM was not distinguishable in adult specimens. The overstretched ALM resulted in movement of the malleus in five cases, but similar tension applied to the DML did not cause any movement of the malleus. This result provides an indication of the clinical significance of the ALM, a ligamentous structure continuous with the SML. It is apparent that the ALM has the potential to cause aural symptoms as a result of damage to the middle ear structure.

Improvement of existing nightsoil treatment plant for nitrogen removal

This study was performed to increase the treatment efficiency and to reduce operation and maintenance costs of the existing nightsoil treatment plant. The existing nightsoil plant was not established by the nitrogen removal process, and was operated ineffectively with deterioration of treatment efficiency rate, and according to the demand of many operators, the expenses of operation and maintenance have become excessive. Modified plant has been changed through two steps. The first step, liquid decayed tank using closed oxidation ditch is operated to increase retention time only for nitrification. The second step, modified liquid decayed tank including anoxic tank is operated, it has an excellent nitrogen removal rate. In first step, when HRT was increased from 10 days to 13 days in liquid decayed tank including aeration tank using closed oxidation ditch, TN concentration of effluent appeared below 51 mg/L less than discharge limit, 60 mg/L. In second step, when anoxic tank and oxic tank were installed, HRT has been increased to 13 days and 26 days, respectively. Then average TN concentration of effluent was detected less than 13 mg/L for over one year. The simple process modified the existing two processes resulted in the reduction of costs for operation and maintenance in the personnel, chemical, and filter change sphere.

Topographic anatomy of the deep temporal nerves, with references to the superior head of lateral pterygoid

Commonly, the nerve branches from the anterior mandibular nerve trunk pass between the roof of infratemporal fossa and the superior head of lateral pterygoid. However, varied courses of the mandibular nerve branches can be frequently observed. The purpose of this study was to clarify the positional relationships and the clinical relevance of the course variations of the branches of the anterior mandibular nerve trunk with reference to the surrounding anatomical structures. Thirty-six hemi-sectioned heads were studied in detail. In 20 cases, the posterior deep temporal nerve had a common trunk with the masseteric nerve and was then divided anteriorly (15 cases) or posteriorly (five cases). In 16 cases, the posterior deep temporal nerve arose from the mandibular nerve trunk independently. Based on the branching patterns of the middle deep temporal nerve, type A (one twig of the middle deep temporal nerve) was most frequent and occurred in 41.7%. Similarly, type B (two twigs), type C (three twigs) and type D (four twigs) were observed in 36.1%, 16.7%, and 5.5%, respectively. The twigs of the middle deep temporal nerve, which pierced the muscle fibers of the superior head of lateral pterygoid, were found in 21 cases (58.3%). Cases in which the middle deep temporal nerve pierced through all areas of the superior head were most frequent (56.5%). These results suggest that the piercing patterns of the middle deep temporal nerve show there is a possibility that it may be compressed during the actions of the superior head of lateral pterygoid.

Bacteriocidal effects and inhibition of cell separation of cinnamic aldehyde on Bacillus cereus

AIMS

In this study, bacteriocidal effects of cinnamic aldehyde on Bacillus cereus were investigated.

METHODS

The bacterial culture or cell suspension in 0.85% NaCl was treated with cinnamic aldehyde at a concentration of 0.3 ml l(-1). Viable cells were counted on a nutrient agar plate. Protein leakage from the cell was determined using a protein dye. Cell morphology was observed using a scanning electron microscope.

RESULTS

Bacillus cereus cells were the most sensitive to cinnamic aldehyde among four different food-borne pathogens. When the cells were treated with 0.3 ml l(-1) of cinnamic aldehyde, the viable counts decreased about 6 log cycles after 6 h of incubation. The bacterial cells remained unlysed although they were killed by cinnamic aldehyde. Treatment of cinnamic aldehyde to the exponential phase cells resulted in no significant protein leakage but strong inhibition of cell separation.

CONCLUSIONS

The present findings suggest that cinnamic aldehyde exhibits bacteriocidal effects and inhibition of cell separation on B. cereus.

SIGNIFICANCE AND IMPACT OF THE STUDY

These data represent an interesting background for a possible mechanism for antibacterial effects of cinnamic aldehyde.

Topographic anatomy of the mandibular nerve branches distributed on the two heads of the lateral pterygoid

The purpose of this study was to evaluate the topography of the nerve distribution on the two heads of the lateral pterygoid and to clarify their morphological-functional correlations. The nerve distribution on the lateral pterygoid was studied in 24 hemi-sectioned heads. Both heads of the lateral pterygoid were innervated from the mandibular nerve branches, but with various nerve distribution patterns. The nerves innervating the superior head of the lateral pterygoid originated from the buccal nerve only in 45.8% of cases. In contrast, the nerves innervating the inferior head of the lateral pterygoid originated from both the buccal and mandibular nerve trunk in 58.3% of cases. In the seven distribution categories of the mandibular nerve branches, both the superior and inferior heads of the lateral pterygoid had a common source of nerve innervation in only 20.8% of cases, the buccal nerve. In contrast, in 45.9% of cases, additional nerve twigs from the mandibular nerve trunk were distributed on the inferior head of the lateral pterygoid. In summary, besides the buccal nerve described in anatomy textbooks, the nerve branches that originated directly from the mandibular nerve trunk innervated the lateral pterygoid.

Dynamics of microcystin-degrading bacteria in mucilage of Microcystis

To reveal the process of degradation of hepatotoxic microcystin produced in Microcystis cells during the Microcystis bloom period, we used fluorescence in situ hybridization (FISH) to analyze the population dynamics of microcystin-degrading bacteria in Microcystis mucilage. We designed and applied an oligonucleotide probe targeted to the 16S rRNA sequence of strain Y2 of a microcystin-degrading bacterium (MCD-bacterium), which was isolated from Lake Suwa, Japan. In both the 1998 and 1999 tests, FISH clearly showed that MCD-bacteria existed in the mucilage and that, when a high concentration of cell-bound microcystin was detected, MCD-bacteria exceeded 10% of the sum of bacteria hybridized with group-specific probes. The concentration of MCD-bacteria was highest in summer 1998, when a toxic species, M. viridis, was dominant. There was a high correlation between the number of MCD-bacteria in the mucilage and the concentration of cell-bound microcystin in the lake. Our results suggest that MCD-bacteria responded to changes in the concentration of microcystin and degraded the microcystin when it was released from Microcystis cells. We also analyzed changes in the bacterial community structure associated with the Microcystis colonies by using domain- and group-specific oligonucleotide probes. Changes in the concentrations of the Cytophaga/Flavobacterium group and delta-Proteobacteria, which can degrade macromolecules derived from Microcystis cells, were synchronized with changes in the concentration of Microcystis. The results not only suggest the significant role of MCD-bacteria in detoxification, but also demonstrate a possible sequence of degradation from Microcystis cells to microcystin maintained in the cell, which is then carried out by bacterial consortia in the mucilage.

Physical properties of an extracellular polysaccharide produced by Bacillus sp. CP912

AIMS

In this study, some physical properties of Bacillus sp. exo-polysaccharide were investigated.

METHODS AND RESULTS

An extracellular polysaccharide was purified by sequential precipitations after homogenization of the diluted culture supernatant of Bacillus sp. CP912. Its physical properties were examined such as lipid emulsifying effect on several vegetable oils and flocculating activity against the activated carbon suspension. The melting point and endothermic calories of the polysaccharide were 128.7 degrees C and 50.864 kCal mol-1, respectively. Its pyrolysis temperature was 284.58 degrees C. The polysaccharide showed high lipid emulsifying activity on oil-water emulsion, against olive, peanut, sunflower and corn oils. It exhibited high flocculating activity as well against activated carbon.

CONCLUSIONS

The present findings suggest that the extracellular polysaccharide produced by Bacillus sp. CP912 has a great industrial potential because of its high lipid emulsifying and flocculating activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

These data represent a novel Bacillus sp. extracellular polysaccharide possessing high emulsifying and flocculating effects.

Degradation of cholesterol by Bacillus subtilis SFF34 isolated from Korean traditional fermented flatfish

AIMS

To examine cholesterol degradation by Bacillus subtilis SFF34.

METHODS AND RESULTS

Cholesterol degradation and cholesterol oxidase production by B. subtilis SFF34 were investigated in a medium containing 0.2% cholesterol. In addition, the oxidized product of cholesterol by the purified cholesterol oxidase was detected using a gas chromatograph. Cholesterol oxidase production reached its maximal level (3.14 U ml(-1) after 24 h of incubation in the cholesterol medium. The residual cholesterol content reduced to 0.98 mg g(-1) after 60 h of cultivation in the cholesterol medium. Two cholesterol oxidases were purified from the culture supernatant fluid and their reaction product against cholesterol was identified as 4-cholesten-3-one.

CONCLUSIONS

B. subtilis SFF34 degraded cholesterol and produced a high level of extracellular cholesterol oxidase.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bacillus subtilis will be very useful for the reduction of cholesterol in many fermented foods and as a source of cholesterol oxidase.

Simultaneous determination of bacterial viability and identity in biofilms using ethidium monoazide and fluorescent in situ hybridization

A protocol for simultaneously interrogating bacterial viability and identity using in situ, culture-independent methods is described. Viability is assayed using ethidium monoazide (EMA) staining of cells with compromised membranes, and identity is determined using fluorescent in situ hybridization (FISH). Experiments with planktonic cultures were used to demonstrate the compatibility of EMA staining and FISH after covalently bonding EMA to nucleic acids by photoreaction. Applications to biofilm samples showed that diffusion limitations in the biofilm matrix were not problematic and that effective discrimination of viable target cells within a mixed microbial community was possible.

Immobilization of poly(ethylene glycol) or its sulfonate onto polymer surfaces by ozone oxidation

A novel surface modification method has been developed to improve biocompatibility of polymeric biomaterials. This approach involves ozonation and then followed by graft polymerization with acrylates containing PEG, sulfonated PEG or by coupling of PEG derivatives. All the reactions were confirmed by ATR FT-IR and ESCA. The degree of ozonation measured by the iodide method was dependent on the ozone permeability of the polymers used. Surface hydrophilicity was investigated by measuring the contact angles. Ozonation itself yielded a slight increase in hydrophilicity and a decrease in platelet adhesion, but PEG immobilization showed a significant effect on surface hydrophilicity and platelet adhesion to confirm well-known PEG's passivity which minimize the adhesion of blood components on polymer surfaces. Both graft polymerization and coupling were effective for PU. In contrast, only grafting gave enough yields for PMMA and silicone. Platelet adhesion results demonstrated that all PEG modified surfaces adsorbed lower platelet adhesion than untreated or ozonated ones. Polymers coupled with sulfonated PEG exhibited the lowest platelet adhesion when compared with control and PEG coupled ones by virtue of the synergistic effect of non-adhesive PEG and negatively charged SO3 groups. This PEG or sulfonated PEG immobilization technology using ozonation is relatively simple for introducing uniform surface modification and therefore very useful for practical application of blood contacting medical devices.

Three glycoproteins with antimutagenic activity identified in Lactobacillus plantarum KLAB21

Antimutagenic substances were purified from a culture supernatant of Lactobacillus plantarum KLAB21 cells isolated from kimchi, a Korean traditional fermented vegetable, and their characteristics were investigated. The antimutagenic substances were separated into two fractions by DEAE-cellulose ion-exchange column chromatography, which were designated the R1 and R2 fractions. The R1 fraction was then divided into two fractions again by Sephadex G200 gel filtration chromatography, and the fractions were designated R1-1 and R1-2. All three fractions were further purified using a Sepharose CL-6B gel filtration column. All the purified fractions were successfully stained with fuchsin as well as Coomassie brilliant blue, suggesting that they are glycoproteins. The purified fractions were confirmed to possess antimutagenic activity against N-methyl-N'-nitro-N-nitrosoguanidine on Salmonella enterica serovar Typhimurium TA100 cells. Their molecular masses were determined to be 16 (R1-1), 11 (R1-2), and 14 (R2) kDa on the Sepharose CL-6B column. Total sugar contents were 8.4% (R1-1), 7.3% (R1-2), and 9.4% (R2). The amino acid compositions of the fractions were different from each other; the major amino acids were glutamic acid (21.5%) and phenylalanine (17.1%) in the R1-1 fraction and glycine (41.3%) in the R1-2 fraction, but valine (31%) and phenylalanine (22.6%) were the major amino acids in the R2 fraction.

An improved method for determination of ethyl carbamate in Korean traditional rice wine

An improved extraction method for ethyl carbamate, a genotoxic and carcinogenic compound found in various fermented foods and beverages, was investigated for its determination in the two most typical Korean traditional rice wines, takju and yakju. When the rice wines were extracted twice with chloroform at 30 degrees C for 60 min, the recovery of ethyl carbamate was less than 16%. When they were saturated with NaCl before extraction, the recovery of ethyl carbamate increased to 24.4% in takju and 67.2% in yakju. Adjustment of pH to 9.0 after NaCl saturation in takju resulted in a dramatic increase of recovery to 81.2%, but not in yakju. When the contents of ethyl carbamate and its precursor, urea, in various Korean traditional rice wines were determined, there was no correlation between the two contents. This is due to the fact that storage time is more important than urea content in the formation of ethyl carbamate in rice wine. In addition, its storage at high temperature resulted in a dramatic increase in ethyl carbamate content according to the prolonged storage time, suggesting that storage time and temperature play a key role in the formation of ethyl carbamate in Korean traditional rice wine.

Effect of poly(ethylene glycol) graft polymerization of poly(methyl methacrylate) on cell adhesion

PURPOSE

To investigate the effect of surface modification of poly(methyl methacrylate) (PMMA) by poly(ethylene glycol) (PEG) grafting on cell adhesion.

SETTING

Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea.

METHODS

The PMMA surface was oxidized with ozone, and PEG acrylate was then graft polymerized. To verify the PEG grafting on the surface, the oxygen content was measured by electron spectroscopy for chemical analysis. The contact angle was measured using the Wilhelmy plate method. The adhesion of keratocytes on modified PMMA was investigated in vitro. Cultured rabbit keratocytes (4 x10(5) cells/mL) were layered on each PMMA disk, cultured in a carbon dioxide incubator for 24 hours, harvested by trypsinization, and counted. A commercially available intraocular lens was modified as described and then inserted in the anterior chamber of a white rabbit. The cell adherence pattern on the modified IOL was examined by scanning electron microscopy.

RESULTS

The PEG-grafted PMMA revealed a higher oxygen content and lower dynamic receding contact angles than the untreated PMMA. The mean number of adhered cells was 72.5 +/- 22 x 10(4)/mL for untreated PMMA. After PEG grafting of 1 hour and ozone oxidation of 2 hours, the adherent cell counts significantly decreased to 6.5 +/- 1.7 x 10(4)/mL and 7.6 +/- 1.6 x 10(4)/mL, respectively (P =.002). Scanning electron microscopy showed small round cells sparsely scattered on the modified PMMA in contrast to the untreated PMMA.

CONCLUSION

Surface modification of PMMA using PEG grafting reduced cell adhesion. This may decrease the incidence of retroprosthetic membrane formation after keratoprosthesis surgery.

Degradation of the cyanobacterial hepatotoxin microcystin by a new bacterium isolated from a hypertrophic lake

A bacterium capable of degrading microcystins-RR, -YR, and -LR was isolated from a hypertrophic lake. The bacterium, designated Y2 and classified phenotypically as a member of the genus Sphingomonas, was shown to be distinct phylogenetically from any established species of Sphingomonas on the basis of 16S rDNA sequencing. The bacterium was tentatively identified as Sphingomonas by manual chemotaxonomy, but 16S rRNA sequencing analysis suggests that it is in fact a new species or even a new genus. When the Y2 bacterium was added to microcystins present in culture medium, the microcystins were degraded thoroughly in 4 days. The highest degradation rates of microcystins-RR and -LR were 13 and 5.4 mg L-1 day-1, respectively. The degradation rates were strongly dependent on temperature and the maximum rate was at 30 degrees C.

Co-production of microcystins and aeruginopeptins by natural cyanobacterial bloom

The relationship between Microcystis composition and the production of microcystins and nontoxic peptides in bloom cells, which was regularly collected in Lake Suwa, Japan, in the summer season from 1991 to 1994, was investigated. In order to determine the structures of the nontoxic peptides, we collected large amounts of bloom materials from the same lake on July 23, 1991, and isolated three nontoxic peptides. They were named as aeruginopeptins 917S-A, -B, and -C, and their structures were mainly determined by a mass spectrometry/mass spectrometry (MS/MS) technique as 19-membered cyclic depsipeptides possessing the Ahp (3-amino-6-hydroxy-2-piperidone) moiety. An analysis of the microcystins and aeruginopeptins in the collected blood cells and their Microcystis composition suggested that the M. aeruginosa large cell size produces both microcystins and aeruginopeptins, and the production of both compounds is genetically closely related.

Differential damage in bacterial cells by microwave radiation on the basis of cell wall structure

Microwave radiation in Escherichia coli and Bacillus subtilis cell suspensions resulted in a dramatic reduction of the viable counts as well as increases in the amounts of DNA and protein released from the cells according to the increase of the final temperature of the cell suspensions. However, no significant reduction of cell density was observed in either cell suspension. It is believed that this is due to the fact that most of the bacterial cells inactivated by microwave radiation remained unlysed. Scanning electron microscopy of the microwave-heated cells revealed severe damage on the surface of most E. coli cells, yet there was no significant change observed in the B. subtilis cells. Microwave-injured E. coli cells were easily lysed in the presence of sodium dodecyl sulfate (SDS), yet B. subtilis cells were resistant to SDS.

Synergistic operation of the CAR2 (Ornithine transaminase) promoter elements in Saccharomyces cerevisiae

Dal82p binds to the UIS(ALL) sites of allophanate-induced genes of the allantoin-degradative pathway and functions synergistically with the GATA family Gln3p and Gat1p transcriptional activators that are responsible for nitrogen catabolite repression-sensitive gene expression. CAR2, which encodes the arginine-degradative enzyme ornithine transaminase, is not nitrogen catabolite repression sensitive, but its expression can be modestly induced by the allantoin pathway inducer. The dominant activators of CAR2 transcription have been thought to be the ArgR and Mcm1 factors, which mediate arginine-dependent induction. These observations prompted us to investigate the structure of the CAR2 promoter with the objectives of determining whether other transcription factors were required for CAR2 expression and, if so, of ascertaining their relative contributions to CAR2's expression and control. We show that Rap1p binds upstream of CAR2 and plays a central role in its induced expression irrespective of whether the inducer is arginine or the allantoin pathway inducer analogue oxalurate (OXLU). Our data also explain the early report that ornithine transaminase production is induced when cells are grown with urea. OXLU induction derives from the Dal82p binding site, which is immediately downstream of the Rap1p site, and Dal82p functions synergistically with Rap1p. This synergism is unlike all other known instances of Dal82p synergism, namely, that with the GATA family transcription activators Gln3p and Gat1p, which occurs only in the presence of an inducer. The observations reported suggest that CAR2 gene expression results from strong constitutive transcriptional activation mediated by Rap1p and Dal82p being balanced by the down regulation of an equally strong transcriptional repressor, Ume6p. This balance is then tipped in the direction of expression by the presence of the inducer. The formal structure of the CAR2 promoter and its operation closely follow the model proposed for CAR1.

Pharmacological characterization of LB50016, N-(4-amino)butyl 3-phenylpyrrolidine derivative, as a new 5-HT1A receptor agonist

LB50016 was characterized as a selective and potent 5-HT1A receptor agonist and evaluate its anxiolytic and antidepressant activities. It shows high affinity for 5-HT1A receptor, moderate affinity for alpha 2 adrenergic and 5-HT2A receptors and no significant affinity for other receptors tested. Hypothermia and increased serum corticosterone level were observed in LB50016-treated rats, which are mediated mostly by post synaptic 5-HT1A receptor activation. In the mouse forced swim model for depression, LB50016-elicited dose-dependent reductions in immobility time, showing ED50 of approximately 3 mg/kg i.p., which was blocked by pretreatment of NAN-190, 5-HT1A antagonist. In face-to-face test for anxiolytic activity in mice, estimated ED50 was 2 mg/kg, i.p. In isolation-induced aggression test with mice, fifty-fold increases in latency to attack were observed at 30 min and last up to 4 h after LB50016 treatment (3 mg/kg, i.p.). Taken together, LB50016-induced pharmacological activities are mediated by activation of 5-HT1A receptors, offering an effective therapeutic candidate in the management of anxiety and depression in humans.

Benzylamine-based selective and orally bioavailable inhibitors of thrombin

A series of p-aminomethylphenylalanine derivatives were investigated as novel thrombin inhibitors. This study led to potent inhibitors of thrombin (Ki up to 3.3 nM) that are trypsin-selective, highly orally bioavailable in rats, and highly permeable across Caco-2 cells. The P1 benzylamine binding mode in the thrombin active site was identified by X-ray crystallographic analysis.

Discovery of LB30057, a benzamidrazone-based selective oral thrombin inhibitor

Systematic variation of the so-called P-pocket moiety of benzamidrazone-based selective thrombin inhibitors led to the discovery of LB30057. It is potent (Ki = 0.38 nM for human thrombin), selective (Ki = 3290 nM for bovine trypsin), and orally bioavailable (58% oral bioavailability in dogs). LB30057 was efficacious in thrombosis animal models.

Identification and estimation of microcystins in freshwater mussels

Accumulation of microcystins mainly produced by cyanobacteria Microcystis was investigated for freshwater mussels and fishes collected from a lake where heavy blooms of Microcystis occurred every year. The identification of microcystins was performed by HPLC equipped with a frit FAB mass spectrometer. Microcystins LR and RR were identified in the mussels Unio douglasiae and Anadonta woodiana, whereas no microcystin was identified by the present method in fishes, such as Cyprinus carpio, Carassius carassius, and Hypomesius transpacificus.

The S. cerevisiae nitrogen starvation-induced Yvh1p and Ptp2p phosphatases play a role in control of sporulation

Starvation for nitrogen in the absence of a fermentable carbon source causes diploid Saccharomyces cerevisiae cells to leave vegetative growth, enter meiosis, and sporulare; the former nutritional condition also induces expression of the YVH1 gene that encodes a protein phosphatase. This correlation prompted us to determine whether the Yvh1p phosphatase was a participant in the network that controls the onset of meiosis and sporulation. We found that expression of the IME2 gene, encoding a protein kinase homologue required for meiosis- and sporulation-specific gene expression, is decreased in a yvh1 disrupted strain. We also observed a decrease, albeit a smaller one, in the expression of IME1 which encodes an activator protein required for IME2 expression. Under identical experimental conditions, expression of the MCKI and IME4 genes (which promote sporulation but do not require Ime1p for expression) was not affected. These results demonstrate the specificity of the yvh1 disruption phenotype. They suggest that decreased steady-state levels of IME1 and IME2 mRNA were not merely the result of non-specific adverse affects on nucleic acid metabolism caused by the yvh1 disruption. Sporulation of a homozygous yvh1 disruption mutant was delayed and less efficient overall compared to an isogenic wild-type strain, a result which correlates with decreased IME1 and IME2 gene expression. We also observed that expression of the PTP2 tyrosine phosphatase gene (a negative regulator of the osmosensing MAP kinase cascade), but not the PTP1 gene (also encoding a tyrosine phosphatase) was induced by nitrogen-starvation. Although disruption of PTP2 alone did not demonstrably affect sporulation or IME2 gene expression, sporulation was decreased more in a yvh1, ptp2 double mutant than in a yvh1 single mutant; it was nearly abolished in the double mutant. These data suggest that the YVH1 and PTP2 encoded phosphatases likely participate in the control network regulating meiosis and sporulation. Expression of YVH1 and PTP2 was not affected by nitrogen source quality (asparagine compared to proline) suggesting that nitrogen starvation-induced YVH1 and PTP2 expression and sensitivity to nitrogen catabolite repression are on two different branches of the nitrogen regulatory network.

Detection of microcystins, a blue-green algal hepatotoxin, in drinking water sampled in Haimen and Fusui, endemic areas of primary liver cancer in China, by highly sensitive immunoassay

An epidemiological survey for the causes of a high incidence of primary liver cancer (PLC) in Haimen city, Jian-Su province and Fusui county, Guangxi province in China, found a close correlation between the incidence of PLC and the drinking of pond and ditch water. With an aim to clarify whether microcystins (MC), a hepatotoxic peptide produced by water bloom algae, contaminate the drinking water in the endemic areas of PLC in China, a highly sensitive enzyme-linked immunosorbent assay with a detection limit of 50 pg/ml, was introduced to monitor the MC. Three trials to survey the drinking water were carried out in 1993-1994. Samples, 1135 in total, were collected from different sources such as: ponds, ditches, rivers, shallow wells and deep wells in Haimen city. The first survey in September 1993 found that three out of 14 ditch water specimens were positive for MC, with a range of 90-460 pg/ml. Several toxic algae such as Oscillatoria agardhii were present in some of the ditches. In the second trial, samples were collected from five ponds/ditches, two rivers, two shallow wells and two deep wells monthly for the whole year of 1994. These data showed that MC was highest in June to September, with a range of 62-296 pg/ml. A third trial on the 989 different water samples collected from the different types of water sources in July 1994 revealed that 17% of the pond/ditch water, 32% of the river water, and 4% of the shallow-well water were positive for MC, with averages of 101, 160 and 68 pg/ml respectively. No MC was detected in deep well water. A similar survey on 26 drinking water samples in Fusui, Guangxi province, demonstrated a high contamination frequency of MC in the water of ponds/ditches and rivers but no MC in shallow and deep wells. These data support a hypothesis that the blue-green algal toxin MC in the drinking water of ponds/ditches and rivers, or both, is one of the risk factors for the high incidence of PLC in China. Based on previous findings on the epidemiology of PLC and the present results from the mass screening of MC in the drinking water, an advisory level of MC in drinking water was proposed to below 0.01 microg/l. The combined effect of a potent hepatocarcinogen AFB1 and an intermittent intake of MC in drinking water in the summer season was discussed as an etiology of PLC.

Effect of O-glycosylated mucin on invasion and metastasis of HM7 human colon cancer cells

Mucinous colorectal cancers have a poorer prognosis than colorectal cancers which produce a low amount of mucin, but the exact mechanism is not well understood. The present study was undertaken to elucidate the possible mechanisms of invasion and metastasis of colon cancer cells producing high levels of mucin using mucin glycosylation inhibitor, benzyl-alpha-N-acetylgalactosamine. The binding activity of treated HM7 cells to endothelial leukocyte adhesion molecule (ELAM-1) was significantly decreased and fixed cell binding of MoAb SNH-3 and 19-9 (specific for sialyl Le(x) and sialyl Le(a), respectively) was also significantly decreased. Metalloproteinase activity in conditioned medium and invasion of matrigel-coated porous filters by treated HM7 cells were decreased. However, there was no difference between control and treated HM7 cells in terms of matrix protein binding. These results suggest that O-glycosylated mucin is important in the invasive and metastatic properties of HM7 human colon cancer cells.

Inhibition of tumorigenic potential and prostate-specific antigen expression in LNCaP human prostate cancer cell line by 13-cis-retinoic acid

Prostate-specific antigen (PSA) is a member of the kallikrein family and has been an important biological marker for prostate cancer. The mechanisms regulating PSA expression in prostatic cancer cells are unclear. The present study was designed to elucidate the role of 13-cis-retinoic acid (RA) in regulation of PSA and the tumorigenic potential of the human prostate cancer cell line LNCaP. The growth regulation of LNCaP cells was examined by DNA synthesis and doubling time. The tumorigenic potential of prostate cancer cells was analyzed by soft agar colony-forming assay, in vitro invasion assay, type IV collagenase assay and binding to extracellular matrix assay. The nuclear receptors for retinoic acid (RAR alpha, -beta, -gamma and RXR alpha, -beta, -gamma) as well as PSA mRNA were determined by Northern blot using specific oligonucleotide probes. Our results suggest that 13-cis-RA significantly inhibits PSA secretion and expression both at the mRNA and protein levels compared with untreated cells. Electron microscopic studies suggest that after 13-cis-RA treatment, cells become more differentiated as they contain lumina, lined by plasma membrane and microvilli. Prostate cancer cell growth and tumorigenic potential after 13-cis-RA treatment was significantly decreased compared with controls. Nude mice tumorigenicity studies showed that 13-cis-RA-treated cells produced significantly smaller tumors compared with untreated cell tumors. There was also a significant increase in the expression of RXRa mRNA after 13-cis-RA treatment compared with untreated cells.