Topological magnetic structure generation using VAE-GAN hybrid model and discriminator-driven latent sampling

Recently, deep generative models using machine intelligence are widely utilized to investigate scientific systems by generating scientific data. In this study, we experiment with a hybrid model of a variational autoencoder (VAE) and a generative adversarial network (GAN) to generate a variety of plausible two-dimensional magnetic topological structure data. Due to the topological properties in the system, numerous and diverse metastable magnetic structures exist, and energy and topological barriers separate them. Thus, generating a variety of plausible spin structures avoiding those barrier states is a challenging problem. The VAE-GAN hybrid model can present an effective approach to this problem because it brings the advantages of both VAE's diversity and GAN's fidelity. It allows one to perform various applications including searching a desired sample from a variety of valid samples. Additionally, we perform a discriminator-driven latent sampling (DDLS) using our hybrid model to improve the quality of generated samples. We confirm that DDLS generates various plausible data with large coverage, following the topological rules of the target system.

Super-resolution of magnetic systems using deep learning

We construct a deep neural network to enhance the resolution of spin structure images formed by spontaneous symmetry breaking in the magnetic systems. Through the deep neural network, an image is expanded to a super-resolution image and reduced to the original image size to be fitted with the input feed image. The network does not require ground truth images in the training process. Therefore, it can be applied when low-resolution images are provided as training datasets, while high-resolution images are not obtainable due to the intrinsic limitation of microscope techniques. To show the usefulness of the network, we train the network with two types of simulated magnetic structure images; one is from self-organized maze patterns made of chiral magnetic structures, and the other is from magnetic domains separated by walls that are topological defects of the system. The network successfully generates high-resolution images highly correlated with the exact solutions in both cases. To investigate the effectiveness and the differences between datasets, we study the network's noise tolerance and compare the networks' reliabilities. The network is applied with experimental data obtained by magneto-optical Kerr effect microscopy and spin-polarized low-energy electron microscopy.

The impact of the modified schedules of anatomy education on students' performance and satisfaction: Responding to COVID-19 pandemic in South Korea

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic substantially undermined medical education and healthcare systems. Owing to the pandemic in South Korea, most medical schools needed to be flexible when conducting online and offline classes, but the guidelines did not reflect the specificity of medical schools. This study described the impact of modified anatomy education schedules at the Seoul National University College of Medicine (SNUCM) on students' academic performance and satisfaction.

METHODS

Anatomy education in SNUCM is divided into three regional units (the upper and lower limbs, trunk, and head and neck). Owing to the COVID-19 pandemic, the schedule was mixed with simultaneous and rotating schedules. The authors conducted exceptions for online lectures, cadaver dissections, and written and practical examinations in three classes of approximately 50 students each. Furthermore, the authors assessed students' performance using three sets of written and practical examinations, and students completed a questionnaire regarding modified anatomy laboratory schedules.

RESULTS

Despite the pandemic events in Seoul and South Korea during the laboratory sessions, all sessions were completed without any confirmed COVID-19 cases among the students, faculty, and staff. Most of the scores on the written and practical examinations significantly decreased in 2020 compared to those in 2019. However, in the trunk session that used the virtual anatomy application, the score on the practical examination in 2020 was significantly higher than that in 2019. Over 70% (79 and 77 out of 105 respondents on the upper and lower limbs and trunk, respectively) and 53% (55/105) students reported that there were no significant difficulties in studying anatomy in a face-to-face laboratory.

CONCLUSIONS

In conclusion, an adequate education program for cadaver dissection should be developed and provided to overcome the pandemic restrictions. The study findings could serve as a reference for anatomy education during the COVID-19 pandemic.

Estimating the effective fields of spin configurations using a deep learning technique

The properties of complicated magnetic domain structures induced by various spin-spin interactions in magnetic systems have been extensively investigated in recent years. To understand the statistical and dynamic properties of complex magnetic structures, it is crucial to obtain information on the effective field distribution over the structure, which is not directly provided by magnetization. In this study, we use a deep learning technique to estimate the effective fields of spin configurations. We construct a deep neural network and train it with spin configuration datasets generated by Monte Carlo simulation. We show that the trained network can successfully estimate the magnetic effective field even though we do not offer explicit Hamiltonian parameter values. The estimated effective field information is highly applicable; it is utilized to reduce noise, correct defects in the magnetization data, generate spin configurations, estimate external field responses, and interpret experimental images.

Magnetic Hamiltonian parameter estimation using deep learning techniques

Understanding spin textures in magnetic systems is extremely important to the spintronics and it is vital to extrapolate the magnetic Hamiltonian parameters through the experimentally determined spin. It can provide a better complementary link between theories and experimental results. We demonstrate deep learning can quantify the magnetic Hamiltonian from magnetic domain images. To train the deep neural network, we generated domain configurations with Monte Carlo method. The errors from the estimations was analyzed with statistical methods and confirmed the network was successfully trained to relate the Hamiltonian parameters with magnetic structure characteristics. The network was applied to estimate experimentally observed domain images. The results are consistent with the reported results, which verifies the effectiveness of our methods. On the basis of our study, we anticipate that the deep learning techniques make a bridge to connect the experimental and theoretical approaches not only in magnetism but also throughout any scientific research.

An innovative magnetic state generator using machine learning techniques

We propose a new efficient algorithm to simulate magnetic structures numerically. It contains a generative model using a complex-valued neural network to generate k-space information. The output information is hermitized and transformed into real-space spin configurations through an inverse fast Fourier transform. The Adam version of stochastic gradient descent is used to minimize the magnetic energy, which is the cost of our algorithm. The algorithm provides the proper ground spin configurations with outstanding performance. In model cases, the algorithm was successfully applied to solve the spin configurations of magnetic chiral structures. The results also showed that a magnetic long-range order could be obtained regardless of the total simulation system size.

Association of preoperative anemia and perioperative allogenic red blood cell transfusion with oncologic outcomes in patients with nonmetastatic colorectal cancer

Background

We investigated whether preoperative anemia and perioperative blood transfusion (pbt) are associated with overall survival and recurrence-free survival in patients with nonmetastatic colorectal cancer.

Methods

From 1 January 2009 to 31 December 2014, 1003 patients with primary colorectal cancer were enrolled in the study. Perioperative clinical and oncologic outcomes were analyzed based on the presence of preoperative anemia and pbt.

Results

Preoperative anemia was found in 468 patients (46.7%). In the anemia and no-anemia groups, pbt was performed in 44% and 15% of patients respectively. Independent predictors for pbt were preoperative anemia, higher American Society of Anesthesiologists score, laparotomy, lengthy operative time, advanced TNM stage, T4 stage, and 30-day morbidity. The use of pbt, but not preoperative anemia, was found to be an independent adverse prognostic factor for overall survival. In terms of recurrence-free survival, the presence of preoperative anemia was similarly not a significant prognostic factor, but the use of pbt was an independent factor for an unfavourable prognosis.

Conclusions

The use of pbt, but not preoperative anemia, was independently associated with worse overall and recurrence-free survival in nonmetastatic colorectal cancer. For better oncologic outcomes, our findings indicate a need to reduce the use of blood transfusion during the perioperative period.

The spin structures of interlayer coupled magnetic films with opposite chirality

Using Monte-Carlo simulations and micromagnetic simulations, we reveal how the spin structural correlation and the skyrmion dynamics are affected by the interlayer coupling in a chiral magnetic bilayer system, in which the two layers have opposite chirality. The interaction through interlayer coupling between chiral magnetic structures influences the static and dynamics properties profoundly. The competition between the Dzyaloshinskii-Moriya interaction and the interlayer interaction allows multiple magnetic structures to be energetically stable, which includes sole skyrmion states (skyrmion appears in only one of the layers) and skyrmion pair states (coupled skyrmions in top and bottom layers). When current driven spin transfer torques are applied to each state, the sole skyrmion state is mainly propelled by a spin transfer torque causing the skyrmion hall effect, but the skyrmion pair state is propelled by a torque from skyrmion-skyrmion interaction and not influenced by the skyrmion hall effect. Also upon application of an external magnetic field, we found the skyrmions in a skyrmion pair state extinguish in an exclusive way, as the annihilation of a skyrmion in one of the layers stabilizes the once paired skyrmion in the other layer, i.e. the skyrmion lattice sites have only one skyrmion in either layer.

MicroRNA-132 and microRNA-223 control positive feedback circuit by regulating FOXO3a in inflammatory bowel disease

BACKGROUND AND AIM

Although many progresses have been achieved for inflammatory bowel disease (IBD), it is still remained as idiopathic disease to be completely controlled. MicroRNAs (miRNAs) have been identified as key players in many human diseases through degradation or translational inhibition of target genes. Because role of miRNAs in IBD is not completely understood yet, we need to identify miRNAs as novel targets for treatment of IBD.

METHODS

Microarray analysis for miRNAs was performed using dextran sulfate sodium-induced colitis samples and selected differentially regulated miRNAs. Candidate genes were validated using in vitro system and IBD patient samples. Molecular mechanism for regulation of inflammatory signaling was identified using gene modulation system of miRNAs.

RESULTS

We selected 14 upregulated and 15 downregulated miRNAs through microarray analysis. Among candidate miRNAs, significant upregulation of miR-132 and miR-223 was confirmed in inflamed mouse tissues as well as human IBD patient tissues. Through bioinformatics analysis, we identified FOXO3a as direct target of miRNAs and confirmed regulatory mechanism using luciferase assay. Expression of miRNAs clearly suppressed the level of IκBα through downregulation of FOXO3a, leading to enhanced NF-κB signaling to promote the production of pro-inflammatory cytokines. The downregulation of FOXO3a concurrent with upregulation of cytokines was significantly reversed by sequestration of miRNAs with miRNA sponges.

CONCLUSIONS

Our findings provided the evidences that miR-132 and 223 are critical mediators in positive circuit for pathogenesis of IBD by negatively regulating FOXO3a to enhance the expression of inflammatory cytokines and can be a good therapeutic target for IBD treatment.

Impact of vitamin D, bisphosphonate, and combination therapy on bone mineral density in kidney transplant patients

BACKGROUND

Osteoporosis can develop and become aggravated in kidney transplant patients; however, the best preventive options for post-transplantation osteoporosis remain controversial.

METHODS

We retrospectively analyzed cohort of 182 renal transplant recipients of mean age 46.7 ± 12.1 years including 47.3% women. Seventy-three patients received neither vitamin D nor bisphosphonate after transplantation (group 1). The other patients were classified into the following 3 groups: calcium plus vitamin D (group 2; n = 40); bisphosphonate (group 3; n = 18); and both regimens (group 4; n = 51). Bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry at baseline and at 1 year after transplantation.

RESULTS

At 1 year after transplantation, T-scores of the femoral neck and entire femur were significantly decreased in group 1 (-0.23 ± 0.65 [P = .004] and -0.21 ± 0.74 [P = .018], respectively), whereas the lumbar spine was significantly increased in group 4 (0.27 ± 0.79; P = .020). Post hoc analysis demonstrated that the delta T-score was significantly lower in group 1 than in group 4 (P = .009, 0.035, and 0.031 for lumbar spine, femoral neck, and entire femur, respectively). In a multivariate analysis adjusted by age, sex, body mass index, dialysis duration, diabetes, calcineurin inhibitors, estimated glomerular filtration rate, and persistent hyperparathyroidism, both group 2 and group 4 showed protective effects on BMD reduction (odds ratio [OR], 0.165; 95% confidence interval [CI] 0.032-0.845 [P = .031]; and OR, 0.169; 95% CI, 0.045-0.626 [P = .008]; respectively). However, group 3 did not show a protective effect (OR, 0.777; 95% CI, 0.198-3.054; P = .718), because their incidence of persistent hyperparathyroidism after transplantation was significantly higher (50.0%) than the other groups (P < .001). The incidence of bone fractures did not differ among the groups.

CONCLUSIONS

Combination therapy with vitamin D and bisphosphonate was the most effective regimen to improve BMD among kidney recipients.

Novel chiral magnetic domain wall structure in Fe/Ni/Cu(001) films

Using spin-polarized low energy electron microscopy, we discovered a new type of domain wall structure in perpendicularly magnetized Fe/Ni bilayers grown epitaxially on Cu(100). Specifically, we observed unexpected Néel-type walls with fixed chirality in the magnetic stripe phase. Furthermore, we find that the chirality of the domain walls is determined by the film growth order with the chirality being right handed in Fe/Ni bilayers and left handed in Ni/Fe bilayers, suggesting that the underlying mechanism is the Dzyaloshinskii-Moriya interaction at the film interfaces. Our observations may open a new route to control chiral spin structures using interfacial engineering in transition metal heterostructures.

Estrogen and hypoxia regulate estrogen receptor alpha in a synergistic manner

Hypoxia activates and degrades estrogen receptor alpha (ERalpha) in human breast cancer cells, which may play an important role in the development and progression of breast cancer. In this study, the synergistic effects of estrogen (E(2)) and hypoxia on ERalpha-mediated transactivation and ERalpha degradation were investigated. ERalpha-mediated transcriptional activity was synergistically increased by E(2) and hypoxia, as determined by the transient expression of ERalpha and ER-responsive reporter plasmids in HEK 293 cells. Twenty hours of E(2) and hypoxia treatment synergistically induced degradation of ERalpha by 95% via a proteasome-dependent pathway in MCF-7 cells. These results provide evidence that hypoxia may stimulate yet unknown factor(s), which can further stimulate ERalpha signal transduction pathways.

Transduction of human catalase mediated by an HIV-1 TAT protein basic domain and arginine-rich peptides into mammalian cells

Antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) have been considered to have a beneficial effect against various diseases mediated by reactive oxygen species (ROS). Although a variety of modified recombinant antioxidant enzymes have been generated to protect against the oxidative stresses, the lack of their transduction ability into cells resulted in limited ability to detoxify intracellular ROS. To render the catalase enzyme capable of detoxifying intracellular ROS when added extracellularly, cell-permeable recombinant catalase proteins were generated. A human liver catalase gene was cloned and fused with a gene fragment encoding the HIV-1 Tat protein transduction domain (RKKRRQRRR) and arginine-rich peptides (RRRRRRRRR) in a bacterial expression vector to produce genetic in-frame Tat-CAT and 9Arg-CAT fusion proteins, respectively. The expressed and purified fusion proteins can be transduced into mammalian cells (HeLa and PC12 cells) in a time- and dose-dependent manner when added exogenously in culture medium, and transduced fusion proteins were enzymatically active and stable for 60 h. When exposed to H(2)O(2), the viability of HeLa cells transduced with Tat-CAT or 9Arg-CAT fusion proteins was significantly increased. In combination with transduced SOD, transduced catalase also resulted in a cooperative increase in cell viability when the cells were treated with paraquat, an intracellular antioxide anion generator. We then evaluated the ability of the catalase fusion proteins to transduce into animal skin. This analysis showed that Tat-CAT and 9Arg-CAT fusion proteins efficiently penetrated the epidermis as well as the dermis of the subcutaneous layer when sprayed on animal skin, as judged by immunohistochemistry and specific enzyme activities. These results suggest that Tat-CAT and 9Arg-CAT fusion proteins can be used in protein therapy for various disorders related to this antioxidant enzyme.

Oxidative modification of human ceruloplasmin by peroxyl radicals

Ceruloplasmin (CP), the blue oxidase present in all vertebrates, is the major copper-containing protein of plasma. We investigated oxidative modification of human CP by peroxyl radicals generated in a solution containing 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). When CP was incubated with AAPH, the aggregation of proteins was increased in a time- and dose-dependent manner. Incubation of CP with AAPH resulted in a loss of ferroxidase activity. Superoxide dismutase and catalase did not protect the aggregation of CP, whereas hydroxyl radical scavengers such as ethanol and mannitol protected the protein aggregation. The aggregation of proteins was significantly inhibited by the copper chelators, diethyldithiocarbamate and penicillamine. Exposure of CP to AAPH led to the release of copper ions from the enzyme and the generation of protein carbonyl derivatives. Subsequently, when the amino acid composition of CP reacted with AAPH was analyzed, cysteine, tryptophan, methionine, histidine, tyrosine, and lysine residues were particularly sensitive.

The changes in the expressions of gamma-aminobutyric acid transporters in the gerbil hippocampal complex following spontaneous seizure

To identify the roles of gamma-aminobutyric acid (GABA) transporter in epileptogenesis and the recovery mechanisms in spontaneous seizure, a chronological and comparative analysis of GABA transporters (GAT) expression was conducted. GAT-1 immunoreactivity was more strongly detected in the pre-seizure group of seizure sensitive (SS) gerbils than that seen in the seizure resistant group. 30 min postictal, the density of GAT-1 immunoreactivity was significantly decreased in the hippocampal complex, as compared to pre-seizure group. 12 h after seizure on-set, the GAT immunodensity recovered to the pre-seizure level. Following the onset of seizure, GAT-3 immunoreactivity remained unchanged. These results suggest that the increase of GAT-1 expression in the SS gerbil hippocampus may affect epileptogenesis in this animal, and the alteration of immunoreactivity following seizure may be compensatory responses to modulate seizure activity.

Suppression of collagen-induced arthritis with histone H1

Besides roles in nucleus mediating the condensation of DNA into chromatin, the involvement of histones in autoimmune diseases, hormone regulation, and killing leukemia cells has been reported. In order to investigate the functions of histones on an autoimmune disease, histone H1 was injected into collagen-induced arthritis (CIA) mice. A dramatic suppression of CIA by histone H1 was observed at a dose of 1 mg/kg bodyweight of mouse. In addition, the increased level of anti-inflammatory cytokine IL-10 was detected in cultured splenocytes from the mouse treated with histone H1. These findings suggest that histone H1 suppresses the collagen-induced arthritis, possibly by increasing the level of IL-10 production.

Comparison of diameter and perimeter methods for tumor volume calculation

PURPOSE

Lesion volume is often used as an end point in clinical trials of oncology therapy. We sought to compare the common method of using orthogonal diameters to estimate lesion volume (the diameter method) with a computer-assisted planimetric technique (the perimeter method).

METHODS

Radiologists reviewed 825 magnetic resonance imaging studies from 219 patients with glioblastoma multiforme. Each study had lesion volume independently estimated via the diameter and perimeter methods. Cystic areas were subtracted out or excluded from the outlined lesion. Inter- and intrareader variability was measured by using multiple readings on 48 cases. Where serial studies were available in noncystic cases, a mock response analysis was used.

RESULTS

The perimeter method had a reduced interreader and intrareader variability compared with the diameter method (using SD of differences): intrareader, 1.76 mL v 7.38 mL (P < .001); interreader, 2.51 mL v 9.07 mL (P < .001) for perimeter and diameter results, respectively. Of the 121 noncystic cases, 23 had serial data. In six (26.1%) of those 23, a classification difference occurred when the perimeter method was used versus the diameter method.

CONCLUSION

Variability of measurements was reduced with the computer-assisted perimeter method compared with the diameter method, which suggests that changes in volume can be detected more accurately with the perimeter method. The differences between these techniques seem large enough to have an impact on grading the response to therapy.

The mouse Ames waltzer hearing-loss mutant is caused by mutation of Pcdh15, a novel protocadherin gene

The neuroepithelia of the inner ear contain hair cells that function as mechanoreceptors to transduce sound and motion signals. Mutations affecting these neuroepithelia cause deafness and vestibular dysfuction in humans. Ames waltzer (av) is a recessive mutation found in mice that causes deafness and a balance disorder associated with the degeneration of inner ear neuroepithelia. Here we report that the gene that harbours the av mutation encodes a novel protocadherin. Cochlear hair cells in the av mutants show abnormal stereocilia by 10 days after birth (P10). This is the first evidence for the requirement of a protocadherin for normal function of the mammalian inner ear.

Oxidative modification and inactivation of Cu,Zn-superoxide dismutase by 2,2'-azobis(2-amidinopropane) dihydrochloride

We have investigated oxidative modification of human Cu, Zn-superoxide dismutase (SOD) by alkylperoxyl radicals and alkylperoxides. To generate free radicals, we used the hydrophilic azocompound, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). When Cu,Zn-SOD was incubated with AAPH, the enzyme activity was decreased gradually in a time-dependent manner. The oxidative damage to Cu,Zn-SOD by AAPH-derived radicals led to protein fragmentation which is associated with the inactivation of enzyme. Incubation with AAPH resulted in the release of copper ions from Cu,Zn-SOD and the generation of protein carbonyl derivatives. Catalase did not protect the fragmentation of Cu,Zn-SOD whereas azide, glutathione and a metal chelator, diethylenetriamine pentaacetic acid inhibited the protein fragmentation. When Cu,Zn-SOD that has been exposed to AAPH was subsequently analyzed by amino acid analysis, lysine, histidine, proline, and valine residues were particularly sensitive. It is suggested that oxidative damage of Cu,Zn-SOD by AAPH-derived radicals may induce the perturbation of cellular antioxidant defense systems and subsequently lead to the deleterious condition in cells.

Transduction of Cu,Zn-superoxide dismutase mediated by an HIV-1 Tat protein basic domain into mammalian cells

A human Cu,Zn-superoxide dismutase (Cu,Zn-SOD) gene was fused with a gene fragment encoding the nine amino acid transactivator of transcription (Tat) protein transduction domain (RKKRRQRRR) of HIV-1 in a bacterial expression vector to produce a genetic in-frame Tat-SOD fusion protein. The expressed and purified Tat-SOD fusion protein in Escherichia coli can enter HeLa cells in a time- and dose-dependent manner when added exogenously in a culture media. Denatured Tat-SOD protein was transduced much more efficiently into cells than were native proteins. Once inside the cells, transduced Tat-SOD protein was enzymatically active and stable for 24 h. The cell viability of HeLa cells treated with paraquat, an intracellular superoxide anion generator, was increased by transduced Tat-SOD. These lines of results suggest that the transduction of Tat-SOD fusion protein may be one of the ways to replenish the Cu,Zn-SOD in the various disorders related to this antioxidant enzyme.

Role of GRPergic neurons in secretin-evoked exocrine secretion in isolated rat pancreas

Effects of intrapancreatic gastrin-releasing peptide (GRP)-containing neurons on secretin-induced pancreatic secretion were investigated in the totally isolated perfused rat pancreas. Electrical field stimulation (EFS) increased secretin (12 pM)-induced pancreatic secretions of fluid and amylase. EFS induced a twofold increase in GRP concentration in portal effluent, which was completely inhibited by tetrodotoxin but not modified by atropine. An anti-GRP antiserum inhibited the EFS-enhanced secretin-induced secretions of fluid and amylase by 12 and 43%, respectively, whereas a simultaneous infusion of the antiserum and atropine completely abolished them. Exogenous GRP dose-dependently increased the secretin-induced pancreatic secretion with an additive effect on fluid secretion and a potentiating effect on amylase secretion, which was not affected by atropine. In conclusion, excitation by EFS of GRPergic neurons in the isolated rat pancreas results in the release of GRP, which exerts an additive effect on fluid secretion and a potentiating effect on amylase secretion stimulated by secretin. The release and action of GRP in the rat pancreas are independent of cholinergic tone.

Fragmentation of human ceruloplasmin induced by hydrogen peroxide

We investigated the fragmentation of human ceruloplasmin induced by H2O2 to study its oxidative damage. When ceruloplasmin was incubated with H2O2, the frequency of the protein fragmentation increased in a proportion to the concentration of H2O2. It also increased in a time-dependent manner and was accompanied by gradual loss of the oxidase activity. Hydroxyl radical scavengers such as azide and mannitol inhibited the fragmentation of ceruloplasmin. The deoxyribose assay showed that hydroxyl radicals were generated in the reaction of ceruloplasmin with H2O2. Incubation of ceruloplasmin with H2O2 resulted in a time-dependent release of copper ions. The released copper ion may participate in a Fenton-like reaction to produce hydroxyl radical, which enhanced the fragmentation. The protection of the fragmentation by copper chelators such as diethylenetriaminepentaacetic acid and bathocuproine indicates a role for copper ion in the reaction. These results suggest that the fragmentation of ceruloplasmin induced by H2O2 is due to hydroxyl radicals formed by a copper-dependent Fenton-like reaction.

Hydrogen peroxide-mediated Cu,Zn-superoxide dismutase fragmentation: protection by carnosine, homocarnosine and anserine

The fragmentation of human Cu,Zn-superoxide dismutase (SOD) was observed during incubation with H(2)O(2). Hydroxyl radical scavengers such as sodium azide, formate and mannitol protected the fragmentation of Cu,Zn-SOD. These results suggested that *OH was implicated in the hydrogen peroxide-mediated Cu,Zn-SOD fragmentation. Carnosine, homocarnosine and anserine have been proposed to act as anti-oxidants in vivo. We investigated whether three compounds could protect the fragmentation of Cu,Zn-SOD induced by H(2)O(2). The results showed that carnosine, homocarnosine and anserine significantly protected the fragmentation of Cu,Zn-SOD. All three compounds also protected the loss of enzyme activity induced by H(2)O(2). Carnosine, homocarnosine and anserine effectively inhibited the formation of *OH by the Cu,Zn-SOD/H(2)O(2) system. These results suggest that carnosine and related compounds can protect the hydrogen peroxide-mediated Cu,Zn-SOD fragmentation through the scavenging of *OH.

The role of growth factor on regeneration of nitric oxide synthase (NOS)--containing nerves after cavernous neurotomy in the rats

Nitric oxide synthase (NOS) containing nerve regeneration can be seen six months after unilateral cavernous nerve neurotomy in rats. However, its molecular mechanism is still unknown. It is believed that growth factors are involved in this phenomenon. In this study we investigated the change of NOS containing nerve fibers and the RNA expression of insulin like growth factor (IGF)-I, nerve growth factor (NGF), transforming growth factor (TGF)-alpha, TGF-beta 1, TGF-beta 2. TGF-beta 3 and NOS on the penis after cavernous nerve neurotomy in rats. Male rats were divided into three groups: (1) sham operation (N = 10); (2) unilateral neurotomy of a 5 mm segment of the cavernous nerve (N = 15); and (3) bilateral neurotomy (n = 15). Electrostimulation of the intact cavernous nerve or pelvic ganglion was performed at one, three and six months. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining was used to identify NOS in the penile nerve fibers. The gene expression for growth factors and bNOS was investigated in corporal tissue by reverse transcriptase-polymerase chain reaction (RT-PCR) using specific oligonucleotide primers. One month after neurotomy, both unilateral and bilateral neurotomy groups showed a significant decrease in NOS-containing nerve fibers on the dorsal and intracavernosal nerves on the side of neurotomy, and a significantly lower mRNA expression of bNOS, IGF-I and TGF-beta 2. At three months, the number of NOS-containing nerve fibers in the unilateral neurotomy group increased only slightly but at six months those in the intracavernosal nerve increased in a significant amount (P < 0.0001), however mRNA expression of bNOS, IGF-I and TGF-beta 2 showed a significant increase as early as at three months. After bilateral neurotomy, the NOS-positive nerve fibers in the dorsal and intracavernosal nerve were significantly decreased at one month and remained so at six months; no erectile response could be elicited by pelvic ganglion stimulation. In the unilateral neurotomy group at six months, more NOS-positive neurons in the pelvic ganglia were found on the intact side than on the side of the neurotomy (P < 0.003), indicating that the regeneration derives from pelvic ganglion neurons on the intact side. Furthermore, electrostimulation in the unilateral neurotomy group revealed a greater maximal intracavernosal pressure and a shorter latency period at six months than at one month (P < 0.014, P < 0.001, respectively). These data suggest that IGF-I and TGF-beta 2 may play a key role in regeneration of NOS-containing nerve fibers in the dorsal and intracavernosal nerves after unilateral cavernous nerve injury.

A new mouse insertional mutation that causes sensorineural deafness and vestibular defects

This article describes a new recessive insertional mutation in the transgenic line TgN2742Rpw that causes deafness and circling behavior in mice. Histologic analysis revealed virtually complete loss of the cochlear neuroepithelium (the organ of Corti) in adult mutant mice. In association with the neuroepithelial changes, there is a dramatic reduction of the cochlear nerve supply. Adult mutants also show morphological defects of the vestibular apparatus, including degeneration of the saccular neuroepithelium and occasional malformation of utricular otoconia. Audiometric evaluations demonstrated that the mice displaying the circling phenotype are completely deaf. Molecular analysis of this mutant line revealed that the transgenic insertion occurred without creating a large deletion of the host DNA sequences. The mutant locus was mapped to a region on mouse chromosome 10, where other spontaneous, recessive mutations causing deafness in mice have been mapped.

Release of adriamycin from poly(gamma-benzyl-L-glutamate)/poly(ethylene oxide) nanoparticles

Prolonged circulation of anticancer agent in blood is expected to decrease the host toxicity and enhance the anticancer activity. The purpose of this study is to develop and characterize the prolonged and sustained release formulation of anticancer agent using biodegradable poly(gamma-benzyl-L-glutamate)/poly(ethylene oxide) (PBLG/PEO) polymer nanoparticles. PBLG/PEO polymer is a hydrophilic/hydrophobic block copolymer and forms a micelle-like structure in solution. Spherical nanoparticles incorporating adriamycin were prepared by a dialysis method. The fluorescence intensity of adriamycin in the nanoparticles was increased when sodium dodecylsulfate was added. It is one of the evidences of entrapment of adriamycin in the polymer nanoparticles. Only 20% of entrapped drug was released in 24 h at 37 degrees C a and the release was dependent on the molecular weight of hydrophobic polymer. The endothermic peak of adriamycin at 197 degrees C disappeared in the nanoparticles system, suggesting the inhibition of a crystallization of adriamycin by polymer adsorption during the precipitation process. The mean residence time of adriamycin from the nanoparticles was more than threefold that from a free adriamycin. These results suggest usefulness of PBLG/PEO nanoparticles as a sustained and prolonged release carrier for adriamycin.

Vagus nerve modulates secretin binding sites in the rat forestomach

Secretin is well known for its inhibitory action on gastric motility. It has been reported that secretin in a physiological dose inhibits gastric motility through mediation by the vagal afferent pathway. Secretin also elicited relaxation of carbachol-stimulated rat forestomach muscle strips by binding to its receptors, suggesting a direct action on this peripheral tissue. We hypothesized that vagal input may affect the action of secretin by modulating the level of secretin receptor in the forestomach. Several treatments, including vagal ligation, vagotomy, perivagal application of capsaicin or colchicine, intravenous infusion of tetrodotoxin, and intraperitoneal injection of atropine, were performed to investigate their effects on secretin receptor binding to forestomach membranes. Specific binding of 125I-labeled secretin to forestomach membranes was significantly decreased (45%) by vagal ligation, vagotomy (50%), or perivagal colchicine treatment (40%). On the contrary, specific binding of 125I-secretin was not affected by perivagal capsaicin treatment, intravenous infusion of tetrodotoxin, or intraperitoneal injection of atropine. By Scatchard analysis of the binding data, the capacity of the high-affinity binding sites in forestomach membranes was found to decrease significantly after vagal ligation compared with membranes from the sham-operated group. However, the affinity at the high-affinity binding sites, the binding parameters of the low-affinity binding sites, and binding specificity were not changed. Vagal ligation but not perivagal capsaicin treatment reduced the inhibitory effect of secretin on bethanechol-stimulated contraction of isolated forestomach muscle strips, causing a right shift in the dose-response curve. These results suggest that vagal input through axonal transport plays a significant role on secretin action by modulating the capacity of secretin binding sites (but not affinity or specificity), at least in rat forestomach.

Effects of intrapancreatic neuronal activation on cholecystokinin-induced exocrine secretion of isolated perfused rat pancreas

The role of intrapancreatic neurons in the action of cholecystokinin (CCK) on pancreatic exocrine secretion of the totally isolated, perfused rat pancreas was investigated. Intrapancreatic neurons were activated by applying electrical field stimulation (EFS) to the isolated pancreas for 45 min. When applying EFS, spontaneous pancreatic secretions of fluid and amylase increased until the second 15-min period of EFS and then decreased during the third 15-min period. Atropine (2 microM) notably reduced the EFS-evoked pancreatic secretions of fluid and amylase. The CCK-induced (10 pM) pancreatic secretions of fluid and amylase elevated further in the first 15-min period of EFS and then gradually resumed to the levels observed during application of CCK alone in the third 15-min period of EFS. However, the CCK-induced pancreatic secretions remained elevated even in the third 15-min period of EFS when an action of endogenous somatostatin was inhibited by cyclo-(7-aminoheptanonyl-Phe-d-Trp-Lys-Thr[BZL]) (10 nM) or pertussis toxin (200 ng/ml). EFS further elevated spontaneous exocrine secretion by the cysteamine-treated (300 mg/kg) pancreas, but this was markedly reduced, to normal levels, by infusing somatostatin (100 pM). EFS increased the numbers of immunoreactive somatostatin cells in the Langerhans' islets. The results indicate that intrapancreatic neuronal activation influences CCK-induced pancreatic secretions in a dual-phase pattern in the rat: an increase during the early phase and a decrease during the late phase. Endogenous somatostatin released from the islets appears to inhibit the enhancing effect of neuronal activation on CCK-induced pancreatic secretion. Of the intrapancreatic neurons, the cholinergic ones appear to predominate in EFS's effects on CCK-induced pancreatic secretion.

Isolation of a multidrug resistance inhibitor from Aconitum pseudo-laeve var. erectum

To overcome multidrug resistance (MDR) in cancer chemotherapy, we prepared various plant extracts and searched for a component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level of mdr1 gene. Of various plant extracts, the MeOH extract of the root of Aconitum pseudo-laeve var. erectum was found to have potent inhibitory activity on MDR. The bioassay-guided fractionation of the MeOH extract of the plant led to the isolation of an alkaloid, lycaconitine, as an active principle. And the IC50 of lycaconitine for KB V20C cells was 74 micrograms/ml.

Significant cholinergic role in secretin-stimulated exocrine secretion in isolated rat pancreas

Effects of intrapancreatic cholinergic activation by electrical field stimulation (EFS) on secretin-stimulated pancreatic exocrine secretion were investigated in the totally isolated perfused rat pancreas. EFS at 15 V, 2 ms, and 8 Hz for 45 min markedly increased spontaneous pancreatic secretion. This increase was completely inhibited by tetrodotoxin (1 microM) but not by hexamethonium (100 microM). Atropine (2 microM) significantly reduced the EFS-evoked volume flow and amylase output by 52% and 80%, respectively. EFS further increased the secretin (12 pM)-stimulated pancreatic secretion of fluid and amylase. The increases of the two parameters were significantly suppressed by atropine by 28% and 72%, respectively. Interestingly, EFS significantly increased concentrations of somatostatin-like immunoreactivity in portal venous effluents. When pertussis toxin (200 ng/ml) or rabbit antisomatostatin serum (0.1 ml/10 ml; titer of 1:50,000) was intra-arterially administered, EFS further increased the secretin-stimulated pancreatic secretion. In conclusion, the activation of intrapancreatic cholinergic neurons potentiated the secretin action on pancreatic exocrine secretion in the rat. This potentiating effect was significantly reduced by local somatostatin released during EFS that activated intrapancreatic cholinergic tone.

Iatrogenic secondary infertility caused by residual intrauterine fetal bone after midtrimester abortion

Eleven women with secondary infertility had ultrasonographic findings of intrauterine calcification. Infertility developed in all women after operative termination of midtrimester pregnancy. Dilation and curettage or hysteroscopic removal confirmed residual fetal bony fragments. The removal of these bony fragments was associated with therapeutic success for infertility.

Saponin contents and anticarcinogenic effects of ginseng depending on types and ages in mice

AIM

To compare the anticarcinogenic effects of fresh, white, and red ginseng (Panax ginseng C A Meyer) roots and their saponins.

METHODS

Lung adenoma in newborn N:GP (S) mice was induced by a subcutaneous injection of benzo(a)pyrene 0.5 mg. After weaning, ginseng powders or extracts were given in the drinking water for 6 wk. In the 9th wk the incidence and multiplicity of lung adenoma were counted.

RESULTS

Anticarcinogenic effects were found in 6-year-dried fresh ginseng, 5- and 6-year white ginseng, and 4-, 5-, and 6-year-red ginseng powders. Anticarcinogenic effects were also found in 6-year-dried fresh ginseng, 5- and 6-year-white ginseng, and 4-, 5-, and 6-year-red ginseng extracts. The content of major ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf, Rg1 showed a little higher tendency in fresh or white ginsengs than red ginseng. This tendency was increased as the cultivation ages were increased. But there was no relationship was found between ginsenoside contents and preparation types or cultivation ages.

CONCLUSION

Long-cultivated ginseng and red ginseng contain a higher amount of anticarcinogenic components.

Effects of partial outlet obstruction on bladder-strip sensitivity to glucose deprivation: an in vitro study in the rat

Partial outlet obstruction has been shown to result in contractile and metabolic dysfunctions. Specifically, there is a greater reduction in the response to field stimulation (FS) in comparison with the responses to bethanechol and KCl, a greater reduction in the tonic response to stimulation in comparison with the phasic response, and a reduction in oxidative metabolism of glucose accompanied by an increase in the glycolytic metabolism of glucose. The specific aim of the current study was to correlate the effects of partial outlet obstruction on the contractile responses of isolated strips of bladder smooth muscle to repetitive stimulation in the presence and absence of glucose. Adult male Sprague-Dawley rats were subjected to partial outlet obstruction by the surgical placement of silk ligatures around the urethra. After 2 weeks, each rate was anesthetized, the bladder was excised, and isolated strip studies were performed. These studies demonstrated that the maximal phasic response to FS was significantly decreased in the obstructed strips as compared with controls, with no difference being noted for responses to bethanechol or KCl; the tonic responses to all forms of stimulation were significantly decreased after obstruction, with the tonic response to FS being decreased to a greater degree than were the tonic responses to bethanechol and KCl; and in the absence of glucose, the tonic responses of control strips to all forms of stimulation were reduced to a greater degree than were the phasic responses. These studies demonstrate that the tonic response to FS is extremely sensitive to fatigue induced by repetitive stimulation.

Small bowel Procardia XL tablet bezoar mimicking cystic pneumatosis intestinalis

Procardia XL Extended Release Tablets are being used with increasing frequency in the treatment of angina and hypertension. Bezoar formation, secondary to retained insoluble medication shells, is an important but less well-known complication. We report the first case of a small bowel bezoar due to this unique medication system.

The role of insulin in the interaction of secretin and cholecystokinin in exocrine secretion of the isolated perfused rat pancreas

To investigate the role of insulin in the potentiation effect of secretin and cholecystokinin (CCK) on pancreatic exocrine secretion, the pancreas was isolated from rats and perfused with modified Krebs-Henseleit solution containing glucose at three concentrations. Intraarterial glucose at concentrations of 2.5, 10, and 25 mM produced modest but significant increases in both the pancreatic flow rate and the amylase output in a concentration-dependent manner. The mixture of secretin and CCK at concentrations of 18.5 and 14 pM, respectively, added to the glucose solutions augmented the pancreatic flow rate and amylase output in relation to the glucose concentration. In the streptozotocin-treated pancreas, the mixture of secretin and CCK failed to augment the pancreatic exocrine secretion unless exogenous insulin was added to the perfusate. Secretin markedly potentiated the CCK-induced amylase output when insulin was present in the circulation. However, CCK did not potentiate the secretin-induced flow rate even if insulin was present in the circulation. Insulin did not affect the actions of secretin alone but it potentiated the actions of CCK alone in both the pancreatic flow rate and the amylase output. It is concluded from the above results that insulin intensifies the combined actions of secretin and CCK in pancreatic exocrine secretion by potentiating the CCK action. Furthermore, in the presence of insulin, secretin is able to potentiate the pancreatic enzyme secretion stimulated by CCK.

Effects of glucose deprivation on the contractile response of the rabbit bladder to repetitive stimulation

The urinary bladder requires an adequate energy supply to maintain contractile function. The primary metabolic fuel is glucose. Through glycolysis and oxidative phosphorylation, high energy phosphates are generated, which in turn supply the metabolic energy for the contractile activities of the urinary bladder. The aim of this study was to determine the effects of glucose deprivation and recovery from glucose deprivation on the phasic and tonic components of the contractile responses of rabbit bladder strips to field stimulation, bethanechol, and KCl. The results can be summarized as follow: In response to glucose deprivation, (1) the tonic responses to field stimulation, bethanechol, and KCl all decreased at a significantly greater rate than the phasic responses; (2) the phasic and tonic responses to field stimulation were both reduced to less than 10% of control within 70 minutes of initiating glucose deprivation; (3) the tonic responses to bethanechol and KCI were reduced to approximately 10% of control within 180 minutes whereas the phasic responses remained stable at 40 and 30%, respectively; and (4) glucose replacement stimulated a rapid and nearly complete recovery of the phasic and tonic components of the responses to field stimulation, bethanechol, and KCI. These results indicate that the tonic responses to all forms of stimulation are more sensitive to glucose deprivation than the phasic responses.

Effect of anoxia on the urethral response to phenylephrine

PURPOSE

Smooth muscle requires oxygen for proper contractile function. In addition, anoxia has been shown to inhibit the contractile response to various forms of stimulation. Continence, at least in part, depends upon active alpha-adrenergic tone, which provides intraurethral tension during bladder filling. The current study was designed to determine the effect of anoxia on the ability of the urethra to sustain tension.

MATERIALS AND METHODS

Standard isolated urethral strip preparations were used to determine the effect of anoxia on the contractile response to phenylephrine; isolated whole urethra preparations were used to determine the effect of anoxia on the intraurethral pressure--flow characteristics.

RESULTS

The peak tension responses of the female and male urethra to phenylephrine were significantly greater than the plateau tension. Anoxia induced an immediate decrease in phenylephrine-stimulated tonic tension to baseline tension. In the whole urethra preparation, phenylephrine increased opening pressure to a greater extent in the male urethra than in the female urethra. In both sexes, anoxia reduced the opening pressure and completely prevented phenylephrine stimulated increases in opening pressure.

CONCLUSION

The tonic response to phenylephrine is lost virtually immediately upon the initiation of hypoxia. This suggests that hypoxia decreases the ability of the urethra to maintain a tonic response to alpha-adrenergic stimulation during bladder filling and may be a factor in incontinence, especially in females.

Pancreatic exocrine secretion in response to median raphe stimulation in anesthetized rats

To investigate a possible role of the central serotonergic system in the central control of pancreatic exocrine secretion, the median raphe nucleus of the anesthetized rat was electrically stimulated. The parameters of the biphasic square wave stimulus were 2 V, 2 ms, and 40 Hz. Electrical stimulation of the median raphe nucleus for 10 min resulted in large increases in pancreatic volume flow and protein output. The pancreatic responses were completely abolished by spinal cord transection at the level between C4 and C5. Cervical vagotomy or adrenalectomy failed to attenuate the pancreatic responses. The median raphe stimulation evoked a remarkable elevation of the blood pressure of the carotid artery as well as the plasma concentrations of noradrenaline and adrenaline. The responses were also completely inhibited by spinal cord transection but unaffected by cervical vagotomy. Adrenalectomy blocked the elevation of the plasma concentration of adrenaline only. Noradrenaline, given intravenously, stimulated the pancreatic volume flow and protein output. The actions of noradrenaline were antagonized by propranolol but not by phentolamine. It is, therefore, concluded from the present study that the median raphe nucleus may play a stimulatory role in pancreatic exocrine secretion of anesthetized rats and that the stimulatory role is mediated via the sympathetic nervous system acting on beta-adrenoceptors.

Molecular structure and chromosomal mapping of the human homolog of the agouti gene

The agouti (a) locus in mouse chromosome 2 normally regulates coat color pigmentation. The mouse agouti gene was recently cloned and shown to encode a distinctive 131-amino acid protein with a consensus signal peptide. Here we describe the cloning of the human homolog of the mouse agouti gene using an interspecies DNA-hybridization approach. Sequence analysis revealed that the coding region of the human agouti gene is 85% identical to the mouse gene and has the potential to encode a protein of 132 amino acids with a consensus signal peptide. Chromosomal assignment using somatic-cell-hybrid mapping panels and fluorescence in situ hybridization demonstrated that the human agouti gene maps to chromosome band 20q11.2. This result revealed that the human agouti gene is closely linked to several traits, including a locus called MODY (for maturity onset diabetes of the young) and another region that is associated with the development of myeloid leukemia. Initial expression studies with RNA from several adult human tissues showed that the human agouti gene is expressed in adipose tissue and testis.

Activity-dependent variations in conduction velocity of C fibers of rat sciatic nerve

Changes in the conduction velocity and subsequent conduction block were characterized following impulse activity in single C fibers of rat sciatic nerves. C fibers which had the same resting conduction velocities often exhibited quite different profiles of the activity-dependent latency change and/or conduction block following impulses. The results imply underlying variation among C fibers in the activity-dependent excitability changes, especially in the build-up and recovery of the hypoexcitable phases.

Candidate gene associated with a mutation causing recessive polycystic kidney disease in mice

A line of transgenic mice was generated that contains an insertional mutation causing a phenotype similar to human autosomal recessive polycystic kidney disease. Homozygotes displayed a complex phenotype that included bilateral polycystic kidneys and an unusual liver lesion. The mutant locus was cloned and characterized through use of the transgene as a molecular marker. Additionally, a candidate polycystic kidney disease (PKD) gene was identified whose structure and expression are directly associated with the mutant locus. A complementary DNA derived from this gene predicted a peptide containing a motif that was originally identified in several genes involved in cell cycle control.

Effects of pancreatic polypeptide on insulin action in exocrine secretion of isolated rat pancreas

1. Effects of pancreatic polypeptide (PP) on insulin action in pancreatic exocrine secretion was investigated by using an isolated rat pancreas that was perfused with Krebs-Henseleit solution containing 2.5 mM glucose, 0.1% bovine serum albumin and 3% Dextran T-70 at a vascular flow rate of 1.2 ml min-1. 2. Cholecystokinin-8 (CCK-8) at a concentration of 14 pM stimulated basal flow rate and amylase output of the isolated pancreas. Twenty-five millimolar glucose not only increased the basal flow rate and amylase output but also potentiated the CCK-stimulated flow rate and amylase output. 3. Porcine insulin, administered intra-arterially at a concentration of 100 nM, also increased the basal flow rate and amylase output, and also potentiated the CCK-stimulated flow rate and amylase output. 4. Rat PP, given intra-arterially at a concentration of 10 pM, completely abolished the potentiation effects of both the 25 mM glucose and the exogenous insulin on the CCK-stimulated flow rate and amylase output. Rat PP also inhibited the flow rate and amylase output increased by either 25 mM glucose alone or exogenous insulin alone. However, rat PP did not change the flow rate and amylase output stimulated by CCK-8 alone. 5. These results indicate that insulin is an important stimulatory hormone of pancreatic exocrine secretion, and that PP exerts the inhibitory role in pancreatic exocrine secretion by modulating the insulin action.

Sulfatide activator protein. Alternative splicing that generates three mRNAs and a newly found mutation responsible for a clinical disease

The sulfatide activator protein, also known as SAP-1, is derived from a gene that generates an mRNA coding for four homologous proteins. Its physiological function is to stimulate hydrolysis of sulfatide by arylsulfatase A in vivo. A genetic defect in the sulfatide activator results in a metabolic disorder similar to classical metachromatic leukodystrophy, which is itself caused by a genetic defect in arylsulfatase A. In a patient with sulfatide activator deficiency, a nucleotide transversion G722----C (counted from A of the initiation codon ATG) was found in the mRNA of the sulfatide activator precursor, resulting in the substitution of serine for Cys241 in the mature sulfatide activator. The remainder of the coding sequence was completely normal except for a polymorphism C to T in position 1389, which does not change the amino acid sequence. The patient produces at least three different forms of mRNA for the precursor. Two of them include a stretch of an additional 9 and 6 bases, respectively, within the sulfatide activator coding region. In normal individuals this stretch of additional bases has also been observed. This could be explained by the presence of a small 9-base pair exon which can be introduced, or not, by alternative splicing as a stretch of 9 or 6 bases into the mature mRNA. The shortest form of the mRNA yields an active sulfatide activator (Fürst, W., Schubert, J., Machleidt, W., Meier, H. E., and Sandhoff, K. (1990) Eur. J. Biochem. 192, 709-714).

The organization of the gene for the human cerebroside sulfate activator protein

The organization of 14 exons covering 97% of the cDNA sequence of human cerebroside sulfate activator protein precursor has been determined from two overlapping EMBL-4 human genomic clones extending over 17 kb. All exons and exon/intron splice junctions and five introns were sequenced. Exon 8 consists of only 9 bp and is involved in alternative splicing which generates three different mRNAs of cerebroside sulfate activator precursor.