Feasibility of fully automated classification of whole slide images based on deep learning

Although microscopic analysis of tissue slides has been the basis for disease diagnosis for decades, intra- and inter-observer variabilities remain issues to be resolved. The recent introduction of digital scanners has allowed for using deep learning in the analysis of tissue images because many whole slide images (WSIs) are accessible to researchers. In the present study, we investigated the possibility of a deep learning-based, fully automated, computer-aided diagnosis system with WSIs from a stomach adenocarcinoma dataset. Three different convolutional neural network architectures were tested to determine the better architecture for tissue classifier. Each network was trained to classify small tissue patches into normal or tumor. Based on the patch-level classification, tumor probability heatmaps can be overlaid on tissue images. We observed three different tissue patterns, including clear normal, clear tumor and ambiguous cases. We suggest that longer inspection time can be assigned to ambiguous cases compared to clear normal cases, increasing the accuracy and efficiency of histopathologic diagnosis by pre-evaluating the status of the WSIs. When the classifier was tested with completely different WSI dataset, the performance was not optimal because of the different tissue preparation quality. By including a small amount of data from the new dataset for training, the performance for the new dataset was much enhanced. These results indicated that WSI dataset should include tissues prepared from many different preparation conditions to construct a generalized tissue classifier. Thus, multi-national/multi-center dataset should be built for the application of deep learning in the real world medical practice.

Dual deep neural network-based classifiers to detect experimental seizures

Manually reviewing electroencephalograms (EEGs) is labor-intensive and demands automated seizure detection systems. To construct an efficient and robust event detector for experimental seizures from continuous EEG monitoring, we combined spectral analysis and deep neural networks. A deep neural network was trained to discriminate periodograms of 5-sec EEG segments from annotated convulsive seizures and the pre- and post-EEG segments. To use the entire EEG for training, a second network was trained with non-seizure EEGs that were misclassified as seizures by the first network. By sequentially applying the dual deep neural networks and simple pre- and post-processing, our autodetector identified all seizure events in 4,272 h of test EEG traces, with only 6 false positive events, corresponding to 100% sensitivity and 98% positive predictive value. Moreover, with pre-processing to reduce the computational burden, scanning and classifying 8,977 h of training and test EEG datasets took only 2.28 h with a personal computer. These results demonstrate that combining a basic feature extractor with dual deep neural networks and rule-based pre- and post-processing can detect convulsive seizures with great accuracy and low computational burden, highlighting the feasibility of our automated seizure detection algorithm.

Central Regulation of Micturition and Its Association With Epilepsy / 대한배뇨장애요실금학회지

Micturition is a complex process involving the bladder, spinal cord, and the brain. Highly sophisticated central neural program controls bladder function by utilizing multiple brain regions, including pons and suprapontine structures. Periaqueductal grey, insula, anterior cingulate cortex, and medial prefrontal cortex are components of suprapontine micturition centers. Under pathologic conditions such as epilepsy, urinary dysfunction is a frequent symptom and it seems to be associated with increased suprapontine cortical activity. Interestingly, micturition can also trigger seizures known as reflex epilepsy. During voiding behavior, frontotemporal cortical activation has been reported and it may induce reflex seizures. As current researches are only limited to present clinical cases, more rigorous investigations are needed to elucidate biological mechanisms of micturition to advance our knowledge on the process of micturition in physiology and pathology.

Enhancement of GluN2B Subunit-Containing NMDA Receptor Underlies Serotonergic Regulation of Long-Term Potentiation after Critical Period in the Rat Visual Cortex

Serotonin [5-hydroxytryptamine (5-HT)] regulates synaptic plasticity in the visual cortex. Although the effects of 5-HT on plasticity showed huge diversity depending on the ages of animals and species, it has been unclear how 5-HT can show such diverse effects. In the rat visual cortex, 5-HT suppressed long-term potentiation (LTP) at 5 weeks but enhanced LTP at 8 weeks. We speculated that this difference may originate from differential regulation of neurotransmission by 5-HT between the age groups. Thus, we investigated the effects of 5-HT on apha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-, gamma-aminobutyric acid receptor type A (GABA(A)R)-, and N-methyl-D-aspartic acid receptor (NMDAR)-mediated neurotransmissions and their involvement in the differential regulation of plasticity between 5 and 8 weeks. AMPAR-mediated currents were not affected by 5-HT at both 5 and 8 weeks. GABA(A)R-mediated currents were enhanced by 5-HT at both age groups. However, 5-HT enhanced NMDAR-mediated currents only at 8 weeks. The enhancement of NMDAR-mediated currents appeared to be mediated by the enhanced function of GluN2B subunit-containing NMDAR. The enhanced GABA(A)R- and NMDAR-mediated neurotransmissions were responsible for the suppression of LTP at 5 weeks and the facilitation of LTP at 8 weeks, respectively. These results indicate that the effects of 5-HT on neurotransmission change with development, and the changes may underlie the differential regulation of synaptic plasticity between different age groups. Thus, the developmental changes in 5-HT function should be carefully considered while investigating the 5-HT-mediated metaplastic control of the cortical network.

Phasic and Tonic Inhibition are Maintained Respectively by CaMKII and PKA in the Rat Visual Cortex

Phasic and tonic gamma-aminobutyric acid(A) (GABA(A)) receptor-mediated inhibition critically regulate neuronal information processing. As these two inhibitory modalities have distinctive features in their receptor composition, subcellular localization of receptors, and the timing of receptor activation, it has been thought that they might exert distinct roles, if not completely separable, in the regulation of neuronal function. Inhibition should be maintained and regulated depending on changes in network activity, since maintenance of excitation-inhibition balance is essential for proper functioning of the nervous system. In the present study, we investigated how phasic and tonic inhibition are maintained and regulated by different signaling cascades. Inhibitory postsynaptic currents were measured as either electrically evoked events or spontaneous events to investigate regulation of phasic inhibition in layer 2/3 pyramidal neurons of the rat visual cortex. Tonic inhibition was assessed as changes in holding currents by the application of the GABA(A) receptor blocker bicuculline. Basal tone of phasic inhibition was maintained by intracellular Ca2+ and Ca2+/calmodulin-dependent protein kinase II (CaMKII). However, maintenance of tonic inhibition relied on protein kinase A activity. Depolarization of membrane potential (5 min of 0 mV holding) potentiated phasic inhibition via Ca2+ and CaMKII but tonic inhibition was not affected. Thus, phasic and tonic inhibition seem to be independently maintained and regulated by different signaling cascades in the same cell. These results suggest that neuromodulatory signals might differentially regulate phasic and tonic inhibition in response to changes in brain states.

Developmental Switch of the Serotonergic Role in the Induction of Synaptic Long-term Potentiation in the Rat Visual Cortex

Synaptic long-term potentiation (LTP) and long-term depression (LTD) have been studied as mechanisms of ocular dominance plasticity in the rat visual cortex. Serotonin (5-hydroxytryptamine, 5-HT) inhibits the induction of LTP and LTD during the critical period of the rat visual cortex (postnatal 3~5 weeks). However, in adult rats, the increase in 5-HT level in the brain by the administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine reinstates ocular dominance plasticity and LTP in the visual cortex. Here, we investigated the effect of 5-HT on the induction of LTP in the visual cortex obtained from 3- to 10-week-old rats. Field potentials in layer 2/3, evoked by the stimulation of underlying layer 4, was potentiated by theta-burst stimulation (TBS) in 3- and 5-week-old rats, then declined to the baseline level with aging to 10 weeks. Whereas 5-HT inhibited the induction of LTP in 5-week-old rats, it reinstated the induction of N-methyl-D-aspartate receptor (NMDA)-dependent LTP in 8- and 10-week-old rats. Moreover, the selective SSRI citalopram reinstated LTP. The potentiating effect of 5-HT at 8 weeks of age was mediated by the activation of 5-HT2 receptors, but not by the activation of either 5-HT1A or 5-HT3 receptors. These results suggested that the effect of 5-HT on the induction of LTP switches from inhibitory in young rats to facilitatory in adult rats.

Octyl Gallate Inhibits ATP-induced Intracellular Calcium Increase in PC12 Cells by Inhibiting Multiple Pathways

Phenolic compounds affect intracellular free Ca2+ concentration ([Ca2+]i) signaling. The study examined whether the simple phenolic compound octyl gallate affects ATP-induced Ca2+ signaling in PC12 cells using fura-2-based digital Ca2+ imaging and whole-cell patch clamping. Treatment with ATP (100 micrometer) for 90 s induced increases in [Ca2+]i in PC12 cells. Pretreatment with octyl gallate (100 nM to 20 micrometer) for 10 min inhibited the ATP-induced [Ca2+]i response in a concentration-dependent manner (IC50=2.84 micrometer). Treatment with octyl gallate (3 micrometer) for 10 min significantly inhibited the ATP-induced response following the removal of extracellular Ca2+ with nominally Ca2+-free HEPES HBSS or depletion of intracellular Ca2+ stores with thapsigargin (1 micrometer). Treatment for 10 min with the L-type Ca2+ channel antagonist nimodipine (1 micrometer) significantly inhibited the ATP-induced [Ca2+]i increase, and treatment with octyl gallate further inhibited the ATP-induced response. Treatment with octyl gallate significantly inhibited the [Ca2+]i increase induced by 50 mM KCl. Pretreatment with protein kinase C inhibitors staurosporin (100 nM) and GF109203X (300 nM), or the tyrosine kinase inhibitor genistein (50 micrometer) did not significantly affect the inhibitory effects of octyl gallate on the ATP-induced response. Treatment with octyl gallate markedly inhibited the ATP-induced currents. Therefore, we conclude that octyl gallate inhibits ATP-induced [Ca2+]i increase in PC12 cells by inhibiting both non-selective P2X receptor-mediated influx of Ca2+ from extracellular space and P2Y receptor-induced release of Ca2+ from intracellular stores in protein kinase-independent manner. In addition, octyl gallate inhibits the ATP-induced Ca2+ responses by inhibiting the secondary activation of voltage-gated Ca2+ channels.

Effects of Serotonin on the Induction of Long-term Depression in the Rat Visual Cortex

Long-term potentiation (LTP) and long-term depression (LTD) have both been studied as mechanisms of ocular dominance plasticity in the rat visual cortex. In a previous study, we suggested that a developmental increase in serotonin [5-hydroxytryptamine (5-HT)] might be involved in the decline of LTP, since 5-HT inhibited its induction. In the present study, to further understand the role of 5-HT in a developmental decrease in plasticity, we investigated the effect of 5-HT on the induction of LTD in the pathway from layer 4 to layer 2/3. LTD was inhibited by 5-HT (10 micrometer) in 5-week-old rats. The inhibitory effect was mediated by activation of 5-HT2 receptors. Since 5-HT also regulates the development of visual cortical circuits, we also investigated the role of 5-HT on the development of inhibition. The development of inhibition was retarded by chronic (2 weeks) depletion of endogenous 5-HT in 5-week-old rats, in which LTD was reinstated. These results suggest that 5-HT regulates the induction of LTD directly via activation of 5-HT2 receptors and indirectly by regulating cortical development. Thus, the present study provides significant insight into the roles of 5-HT on the development of visual cortical circuits and on the age-dependent decline of long-term synaptic plasticity.

The Development of Phasic and Tonic Inhibition in the Rat Visual Cortex

Gamma-aminobutyric acid (GABA)-ergic inhibition is important in the function of the visual cortex. In a previous study, we reported a developmental increase in GABAA receptor-mediated inhibition in the rat visual cortex from 3 to 5 weeks of age. Because this developmental increase is crucial to the regulation of the induction of long-term synaptic plasticity, in the present study we investigated in detail the postnatal development of phasic and tonic inhibition. The amplitude of phasic inhibition evoked by electrical stimulation increased during development from 3 to 8 weeks of age, and the peak time and decay kinetics of inhibitory postsynaptic potential (IPSP) and current (IPSC) slowed progressively. Since the membrane time constant decreased during this period, passive membrane properties might not be involved in the kinetic changes of IPSP and IPSC. Tonic inhibition, another mode of GABAA receptor-mediated inhibition, also increased developmentally and reached a plateau at 5 weeks of age. These results indicate that the time course of the postnatal development of GABAergic inhibition matched well that of the functional maturation of the visual cortex. Thus, the present study provides significant insight into the roles of inhibitory development in the functional maturation of the visual cortical circuits.

Effects of Apigenin on Glutamate-induced Ca2+i Increases in Cultured Rat Hippocampal Neurons

Flavonoids have been shown to affect calcium signaling in neurons. However, there are no reports on the effect of apigenin on glutamate-induced calcium signaling in neurons. We investigated whether apigenin affects glutamate-induced increase of free intracellular Ca2+concentration ([Ca2+]i) in cultured rat hippocampal neurons, using fura-2-based digital calcium imaging and microfluorimetry. The hippocampal neurons were used between 10 and 13 days in culture from embryonic day 18 rats. Pretreatment of the cells with apigenin (1micrometerto 100micrometer for 5 min inhibited glutamate (100 micrometer 1 min) induced [Ca2+]i increase, concentration-dependently. Pretreatment with apigenin (30micrometer for 5 min significantly decreased the [Ca2+]i responses induced by two ionotropic glutamate receptor agonists, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA, 10 micrometer 1 min) and N-methyl-D-aspartate (NMDA, 100 micrometer 1 min), and significantly inhibited the AMPA-induced peak currents. Treatment with apigenin also significantly inhibited the [Ca2+]i response induced by 50 mM KCl solution, decreased the [Ca2+]i responses induced by the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxyphenylglycine (DHPG, 100micrometer 90 s), and inhibited the caffeine (10 mM, 2 min)-induced [Ca2+]i responses. Furthermore, treatment with apigenin (30micrometer significantly inhibited the amplitude and frequency of 0.1 mM [Mg2+o-induced [Ca2+]i spikes. These data together suggest that apigenin inhibits glutamate-induced calcium signaling in cultured rat hippocampal neurons.

Interutricular and Intermastoid Distance Measured in the Koreans Using MRI / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The distance between the utricles is important in vestibular tests like the unilateral centrifugation test for examining the utricular function. In this test, the axis of rotation crosses precisely through one utricle, thus only the opposite utricle is stimulated. The interutricular distance needs to be known in order to stimulate one utricle maximally for this test, and it would be better if the distance could be estimated from surface landmarks like intermastoid distance. SUBJECTS AND METHOD: We investigated the correlation between the interutricular distance (IUD) and the intermastoid distance (IMD), measured on magnetic resonance images. Data were collected from 177 subjects (72 men and 105 women), who suffered from dizziness, sensorineural hearing loss and facial nerve disorders. RESULTS: We found that IUDs were 7.33+/-0.42 cm (6.03-8.75 cm) and the maximum difference of IUDs between the subjects was 2.73 cm. There was a significant correlation between IUD and IMD. The IUDs of men (7.57+/-0.38 cm) and women (7.17+/-0.38 cm) showed the similar correlation with those of IMD. The correlation was not different from that published for Caucasian subjects. CONCLUSION: These findings show that there is a significant correlation between IUD and IMD. IMD can be useful for estimating IUD, which enables exact stimulation to be given to the unilateral utricle in the unilateral centrifugation test. Moreover, individual assessment of IUD gives more precise stimulation than using a fixed IUD in the unilateral centrifugation test.

The Effect of Somatosensory Input on Subjective Visual Vertical in Normal Subjects

BACKGROUND AND OBJECTIVES: Aims of the study were to determine if the somatosensory input influences on vertical perception by comparing the results with the head or body tilted (15Degree to the right and to the left, and to examine the influence of tactile sensation in the perception of verticality in head lateral positions. MATERIALS AND METHOD: We tested 34 normal subjects in their ability to set a straight line to the perceived gravitational vertical. Measurements were taken in static conditions, sitting upright, head tilted (15Degree, body tilted (15Degree, and head lateral positions (90Degree on the right/left sides with or without physical support under the head. RESULTS: The normal range of the subjective visual vertical (SVV) was 0.65Degree/-.23Degreein upright position. The normal ranges of SVV in head-tilts 15Degreeto the left/right sides were -0.47Degree/-.76Degreeand 1.88Degree/-.94Degree which were significantly different from those in upright position (E-effect). But the normal ranges of SVV in body-tilts 15Degreeto the left/right were not different from those in upright position. And the normal ranges of SVV in head lateral positions maintained actively and passively were not different each other, but significantly larger than that in upright position (A-effect). CONCLUSION: Our results support that neck somatosensory input plays a part in the perception of verticality. In contrast, tactile sensation of the head had no effect on the settings of a visual line to visual vertical in head lateral positions.

The Effect of Allergen Provocation on the Nasal Cycle / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Nasal airflow is asymmetrical and is subjected to spontaneous reciprocal changes which are referred to as the nasal cycle. Limited information is available about how they are affected by allergens. The purpose of this study was to evaluate effects of allergen provocation on the nasal cycle. SUBJECTS AND METHOD: This study was performed in 11 patients with allergic rhinitis and 6 healthy controls. Acoustic rhinometry was used to test subjects before and after the allergen provocation. The subjects underwent acoustic rhinometry in 15 minutes interval for evaluation of nasal cycle and 3 minutes interval for immediate response. RESULTS: With the allergic subjects, 10 of the 11 subjects (90.9%) showed nasal cycle and they still had nasal cycle after the allergen provocation. In the study on the changes of the immediate responses, recovery time was on the average of 33.0 minutes and reduction rate of non-patent side was higher than that of patient side. And the period of nasal cycle was on the average of 173 minutes before the allergen provocation and the average 159 minutes after the allergen provocation; there were no statistical differences. The amplitude of each nasal cycle increased after allergen provocation and the difference had statistical meaning. CONCLUSION: Overall duration and reciprocity of nasal cycle were not changed after the allergen provocation and the amplitude of nasal cycle was increased significantly after the allergen provocation.

Tretment Effect of Bromocriptine on Antipsychotics-induced Amenorrhea / 대한정신약물학회지

Amenorrhea is one of the well-known side effects of antipsychotics in women. It is associated with hyperprolactinemia induced by dopamine blocking effect of antipsychotics. Administration of bromocriptine which belongs to dopamine agonist may reverse amenorrhea and hyperprolactinemia. However dopamine agonist has been reserved in the treatment of antipsychotics-induced amenorrhea because of concern about exacerbation of psychotic symptoms. This case series study was designed to determine whether bromocriptine can be used safely in schizophrenic patients with amenorrhea. We administered bromocriptine to 5 stable schizophrenic outpatients who experienced amenorrhea over 6 months. Bromocrptine dosage was titrated upward from 2.5 mg/day to 7.5 mg/day until menstrual recovery. Patients' menstrual state and side effects of bromocriptine was monitored prospectively for 22 weeks, and clinical symptom were assessed using brief psychiatric rating scale (BPRS) and clinical global impression scale-severity (CGI-S). These were assessed biweekly until 12th week and then every 4weeks thereafter. All five patients resumed menstruation without deterioration of clinical symptoms measured by BPRS and CGI-S. No serious side effect of bromocriptine was reported. Patients with lower baseline prolactin level showed faster recovery and needed lower dose of bromocriptine. These findings suggest bromocriptine may be used safely in the treatment of antipsychotics-induced amenorrhea.

Direct and Indirect Cost of Treating Out-Patients with Schizophrenia in Korea / 신경정신의학

OBJECTIVES: We have aimed to estimate the direct and indirect costs of treating out-patients with schizophrenia in Korea, to use this fundamental data for the effective management and proper distribution of the medical resource. METHOD: To estimate the direct cost, we surveyed the medical cost and time of two hundred and eighty-nine out-patients with schizophrenia for six months. And the lost productivity as many months was converted into the indirect cost. Those of eighty-two coronary heart disease patients were also estimated as a comparison group. RESULTS: An unemployement rate of schizophrenic patients was 72.1 percent. Moreover the ratio of the laborer in the sample was, even if employed, 64.5 percent. The mean direct cost of schizo-phrenic patients was, about 815,000 won, higher than that of coronary heart disease, 715,000 won however it was not statistically significant. The former was also estimated 2.5 times more than the latter for the indirect cost, or 6,456, 000 won versus 2,589,000 won. CONCLUSION: Schizophrenia is a relatively costly illness compared to other chronic illness, so the systematic estimation of the cost is necessary to provide mental health service of high quality.