Model-based analysis of the acute effects of transcutaneous magnetic spinal cord stimulation on micturition after spinal cord injury in humans.

AIM: After spinal cord injuries (SCIs), patients may develop either detrusor-sphincter dyssynergia (DSD) or urinary incontinence, depending on the level of the spinal injury. DSD and incontinence reflect the loss of coordinated neural control among the detrusor muscle, which increases bladder pressure to facilitate urination, and urethral sphincters and pelvic floor muscles, which control the bladder outlet to restrict or permit bladder emptying. Transcutaneous magnetic stimulation (TMS) applied to the spinal cord after SCI reduced DSD and incontinence. We defined, within a mathematical model, the minimum neuronal elements necessary to replicate neurogenic dysfunction of the bladder after a SCI and incorporated into this model the minimum additional neurophysiological features sufficient to replicate the improvements in bladder function associated with lumbar TMS of the spine in patients with SCI. METHODS: We created a computational model of the neural circuit of micturition based on Hodgkin-Huxley equations that replicated normal bladder function. We added interneurons and increased network complexity to reproduce dysfunctional micturition after SCI, and we increased the density and complexity of interactions of both inhibitory and excitatory lumbar spinal interneurons responsive to TMS to provide a more diverse set of spinal responses to intrinsic and extrinsic activation of spinal interneurons that remains after SCI. RESULTS: The model reproduced the re-emergence of a spinal voiding reflex after SCI. When we investigated the effect of monophasic and biphasic TMS at two frequencies applied at or below T10, the model replicated the improved coordination between detrusor and external urethral sphincter activity that has been observed clinically: low-frequency TMS (1 Hz) within the model normalized control of voiding after SCI, whereas high-frequency TMS (30 Hz) enhanced urine storage. CONCLUSION: Neuroplasticity and increased complexity of interactions among lumbar interneurons, beyond what is necessary to simulate normal bladder function, must be present in order to replicate the effects of SCI on control of micturition, and both neuronal and network modifications of lumbar interneurons are essential to understand the mechanisms whereby TMS reduced bladder dysfunction after SCI.

Favorable outcome with direct-acting antiviral treatment in hepatitis C patients coinfected with HIV.

AIM: To investigate the efficacy and safety of all-oral direct-acting antiviral treatments in patients coinfected with hepatitis C virus (HCV) and HIV. METHODS: In all, 35 patients with HCV/HIV coinfection (22 patients with HCV genotype 1 infection, 6 with genotype 2, and 7 with genotype 3) were treated with sofosbuvir and ledipasvir (for genotype 1 patients) or sofosbuvir and ribavirin (for genotypes 2 and 3). Sustained virological response (SVR) at 24 weeks after end of treatment and adverse events were assessed. RESULTS: The overall SVR rate was 91.4% (32/35). One patient with genotype 1 infection discontinued treatment on day 2 due to severe headache, which subsided after the cessation of medication; all other patients completed their treatment without severe adverse events. Two patients who had a relapse of HCV were infected with a genotype 3 strain. We observed hyperbilirubinemia in a patient with genotype 3, who was under antiretroviral therapy including atazanavir. He completed the treatment and achieved SVR. CONCLUSION: Direct-acting antiviral treatment for patients coinfected with HCV/HIV is as effective as in patients infected only with HCV. It was generally well tolerated, except in one patient who discontinued the treatment due to severe headache.

[A case of refractory pouchitis following surgery for ulcerative colitis successfully treated with adalimumab].

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is widely accepted as the operation of choice for refractory ulcerative colitis (UC), UC with dysplasia or cancer, or familial adenomatous polyposis. Pouchitis is the most frequent complication after IPAA for UC. Although the pathogenesis of pouchitis remains unclear, current evidence suggests that dysbiosis and mucosal immune response are important mechanisms. Antibiotics are the first-line treatment for the condition, but some patients develop chronic refractory pouchitis. Such cases can be treated with regimens such as longer courses of antibiotic combinations, mesalazine, corticosteroids, probiotics, or biologics. But if pouch inflammation is not ameliorated, a permanent ileostomy may be required. A 40-year-old man had undergone IPAA for UC and was diagnosed with pouchitis according to the Pouchitis Disease Activity Index. Antibiotics, mesalazine, and corticosteroids were given, but the inflammation was difficult to control. He developed chronic refractory pouchitis associated with perianal abscesses and anal fistulae. Following a seton procedure for fistulae, adalimumab (ADA) was administered. After 42 weeks, the ulcers in the pouch became scarred, and the anal fistulae were closed endoscopically. After remission was induced, it has been maintained. ADA is a fully human anti-tumor necrosis factor-α (TNF-α) monoclonal antibody that has been successfully used to treat refractory Crohn disease of the ileoanal pouch. Although some studies report that infliximab, a chimeric anti-TNF-α monoclonal antibody, is efficacious in patients with refractory pouchitis, clinical evidence for the use of ADA is limited. This case illustrates achievement of induction and maintenance of remission of refractory pouchitis with ADA. It is possible that patients with this condition can avoid a permanent ileostomy with anti-TNF-α therapy. In the near future, further study of long-term clinical outcomes of anti-TNF-α therapy is expected.

[Recurrent Gastric Cancer with Tumor Bleeding from a Metastatic Lymph Node Invading the Duodenal Stump Successfully Controlled by Palliative Radiotherapy-A Case Report].

An 82-year-old man receiving oral administration of warfarin for atrial fibrillation underwent distal gastrectomy for advanced gastric cancer. The postoperative diagnosis was pT3(SS)N2M1H1P0CY0, pStage Ⅳ,(HER2, score 3+)gastric cancer. He received chemotherapy for the treatment of multiple liver metastases, following which, he developed lymph node metastases. Grade 3 anemia was observed at 46 months after initiation of chemotherapy when he was treated with third-line irinotecan plus cisplatin. Abdominal CT showed that CR for liver metastases and SD for lymph node metastases were maintained. Esophagogastroduodenoscopy and colonoscopy showed no intraluminal bleeding. As the anemia progressed, blood transfusion was required repeatedly instead of withdrawal of chemotherapy and replacement therapy of iron and vitamin B12. Double- balloon endoscopy revealed hemorrhagic tumor at duodenal stump. We diagnosed tumor bleeding from metastatic lymph node around pancreatic head invading to duodenum. Palliative radiotherapy(40 Gy/20 Fr)for hemostasis was performed. Finally, hemostasis and tumor shrinkage were achieved.

Biological clockwork underlying adaptive rhythmic movements.

Owing to the complexity of neuronal circuits, precise mathematical descriptions of brain functions remain an elusive ambition. A more modest focus of many neuroscientists, central pattern generators, are more tractable neuronal circuits specialized to generate rhythmic movements, including locomotion. The relative simplicity and well-defined motor functions of these circuits provide an opportunity for uncovering fundamental principles of neuronal information processing. Here we present the culmination of mathematical analysis that captures the adaptive behaviors emerging from interactions between a central pattern generator, the body, and the physical environment during locomotion. The biologically realistic model describes the undulatory motions of swimming leeches with quantitative accuracy and, without further parameter tuning, predicts the sweeping changes in oscillation patterns of leeches undulating in air or swimming in high-viscosity fluid. The study demonstrates that central pattern generators are capable of adapting oscillations to the environment through sensory feedback, but without guidance from the brain.

A case report of a duodenal adenocarcinoma: a complication with Crohn's disease.

The prevalence of Crohn's disease (CD) in Japan is increasing, and so is the incidence of colorectal and small bowel cancers associated with CD. However, few reports have described the malignant transformation of duodenal lesions; moreover, such a diagnosis is rarely possible preoperatively. We present a case of malignant degeneration in the duodenal mucosa associated with CD. A 54-year-old man had been receiving treatment for CD for more than 20 years. Seven years ago, he was diagnosed with duodenal stenosis related to CD. He was asymptomatic, and biopsy results from the proximal stricture showed inflammatory changes without malignant transformation. The lesion was then monitored during follow-up. In 2013, he underwent an endoscopy, which revealed an ulcerated, nodular mucosa, immediately proximal to a high-grade obstruction of the descending duodenum. A biopsy of the ulcer lesion confirmed a diagnosis of adenocarcinoma. The patient then underwent duodenopancreatectomy. Histopathological results from the resected duodenum confirmed a poorly differentiated adenocarcinoma that had invaded the subserosa. The patient recovered, and no recurrence has been observed. Although the duodenum can be accessed without difficulty during endoscopy, it is challenging to preoperatively diagnose malignant transformation. There are only four reported cases of duodenal cancer stemming from CD-associated stricture, and only one of them received a preoperative diagnosis of malignancy based on endoscopic biopsy results. Progressive duodenal narrowing and ulceration in patients with CD should indicate a need for careful endoscopic evaluation and biopsy in order to exclude malignant degeneration of Crohn's duodenitis. Early diagnosis of cases of CD-associated cancers is necessary. We report the features of a rare and illustrative case of duodenal adenocarcinoma in a patient with CD.

Administration of low-dose epoetin-alpha facilitates adherence to ribavirin in triple therapy with pegylated interferon-alpha-2b and telaprevir.

AIM: Anemia frequently develops in patients given pegylated interferon, ribavirin (RBV), telaprevir (TVR) triple therapy and restricts treatment by forcing reduction or discontinuation of RBV administration. We investigated whether erythropoietin (EPO) could alleviate RBV-induced anemia to help maintain the RBV dose during the first 12 weeks, the triple therapy phase. METHODS: Twenty-two patients with hepatitis C virus (HCV) genotype 1 were enrolled. Hemoglobin (Hb) concentration was measured every week. If Hb reduction from the baseline was 2 g/dL or more, 12 000 IU of epoetin-α was administrated. When further reduction (≥3 g/dL) was observed, 24 000 IU of epoetin-α was used. Inosine triphosphatase (ITPA) single nucleotide polymorphism (rs1127354) was genotyped for all patients. RESULTS: Among the 22 patients enrolled in this study, three required RBV dose reduction due to anemia, two had to discontinue or reduce TVR and RBV due to creatinine elevation. The remaining 17 patients completed the treatment during the triple therapy phase without reduction of the RBV dose or adverse events attributable to EPO. Regardless of ITPA genotype, Hb decline was well controlled by EPO administration, whereas the total EPO dose tended to be higher in the CC genotype group. The average adherence to RBV during the triple therapy phase was 97.5%. SVR was achieved in 17 patients; two patients had viral breakthrough and three patients had relapse of HCV RNA. CONCLUSION: EPO can be a favorable alternative to reduction of RBV to facilitate the adherence of patients on TVR-based triple therapy.

Plasmablastic lymphoma occurring in ulcerative colitis during treatment with immunosuppressive therapy.

A 53-year-old man who had a history of ulcerative colitis (UC) for 2 years underwent colonoscopy as regular follow-up. The results showed an elevated lesion in the descending colon, which was diagnosed as plasmablastic lymphoma (PBL) based on pathological findings. In situ hybridization for the Epstein-Barr virus-encoded RNA probe was positive. Fluorescence in situ hybridization revealed rearrangement of the MYC gene. He had been taking prednisolone, 5-aminosalicylic acid, azathiopurine, and ustekinumab at the diagnosis of PBL and had multiple prior therapies for UC including infliximab, tacrolimus, and tofacitinib due to steroid dependence. PBL is a rare aggressive B cell lymphoma initially described in the oral cavity of human immunodeficiency virus positive patients and it is suspected to have an association with immunocompromised status of patients. The number of cases of PBL in inflammatory bowel disease (IBD) patients is extremely rare. All these patients were administered immunosuppressive therapy including thiopurines or biologics. IBD patients with immunosuppressive therapy have a higher potential for developing lymphoproliferative disorders. Clinicians should be aware of the risk of lymphoma, including PBL.

Mechanisms underlying rhythmic locomotion: interactions between activation, tension and body curvature waves.

Undulatory animal locomotion arises from three closely related propagating waves that sweep rostrocaudally along the body: activation of segmental muscles by motoneurons (MNs), strain of the body wall, and muscle tension induced by activation and strain. Neuromechanical models that predict the relative propagation speeds of neural/muscle activation, muscle tension and body curvature can reveal crucial underlying control features of the central nervous system and the power-generating mechanisms of the muscle. We provide an analytical explanation of the relative speeds of these three waves based on a model of neuromuscular activation and a model of the body-fluid interactions for leech anguilliform-like swimming. First, we deduced the motoneuron spike frequencies that activate the muscle and the resulting muscle tension during swimming in intact leeches from muscle bending moments. Muscle bending moments were derived from our video-recorded kinematic motion data by our body-fluid interaction model. The phase relationships of neural activation and muscle tension in the strain cycle were then calculated. Our study predicts that the MN activation and body curvature waves have roughly the same speed (the ratio of curvature to MN activation speed ≈0.84), whereas the tension wave travels about twice as fast. The high speed of the tension wave resulting from slow MN activation is explained by the multiplicative effects of MN activation and muscle strain on tension development. That is, the product of two slower waves (activation and strain) with appropriate amplitude, bias and phase can generate a tension wave with twice the propagation speed of the factors. Our study predicts that (1) the bending moment required for swimming is achieved by minimal MN spike frequency, rather than by minimal muscle tension; (2) MN activity is greater in the mid-body than in the head and tail regions; (3) inhibitory MNs not only accelerate the muscle relaxation but also reduce the intrinsic tonus tension during one sector of the swim cycle; and (4) movements of the caudal end are passive during swimming. These predictions await verification or rejection through further experiments on swimming animals.

Mate choice for body size leads to size assortative mating in the Ryukyu Scops Owl Otus elegans.

Understanding evolutionary phenomena that involve size assortative mating requires elucidating the generating mechanisms on which assortment is based. Although various mechanisms have been suggested, their relative importance may differ across taxonomic groups. Males selecting for large, fecund females combined with the dominance of large males in the competition for females has been suggested as a major mechanism in specific groups. However, raptors do not appear to conform to this, because the selection for smallness among males (assumed in a theory of reversed sexual size dimorphism) and the selection for largeness among males (assumed in the theory of size assortative mating) are in opposite directions. We studied the assortative mating during a long-term study of the Ryukyu Scops Owls Otus elegans interpositus. Significant assortative mating was found for culmen length (from the base to the tip of the bill) and wing length (from the bend of the wing to the tip of the longest primary). Statistical control of the spatial and temporal accessibility of potential mates did not affect the assortment. Males with short wings had slightly higher fitness components than those with long wings, and females settling early tended to have small wings. Considering that early-settling females can preferentially choose their mates, these results suggest that smaller females have an advantage when choosing smaller males with good reproductive performance. Improved flying and hunting ability of smaller individuals may be the background of choosing smaller individuals. We propose that, not passive process like similarity between individuals and their potential mates, but active mate choice for small individuals is an explanation for the assortative mating in this owl.

Mechanisms underlying rhythmic locomotion: dynamics of muscle activation.

We have studied the dynamical properties of tension development in leech longitudinal muscle during swimming. A new method is proposed for modeling muscle properties under functionally relevant conditions where the muscle is subjected to both periodic activation and rhythmic length changes. The 'dual-sinusoid' experiments were conducted on preparations of leech nerve cord and body wall. The longitudinal muscle was activated periodically by injection of sinusoidal currents into an identified motoneuron. Simultaneously, sinusoidal length changes were imposed on the body wall with prescribed phase differences (12 values equally spaced over 2π radians) with respect to the current injection. Through the singular value decomposition of appropriately constructed tension data matrices, the leech muscle was found to have a multiplicative structure in which the tension was expressed as the product of activation and length factors. The time courses of activation and length factors were determined from the tension data and were used to develop component models. The proposed modeling method is a general one and is applicable to contractile elements for which the effects of series elasticity are negligible.

Analysis of impulse adaptation in motoneurons.

Animal locomotion results from muscle contraction and relaxation cycles that are generated within the central nervous system and then are relayed to the periphery by motoneurons. Thus, motoneuron function is an essential element for understanding control of animal locomotion. This paper presents motoneuron input-output relationships, including impulse adaptation, in the medicinal leech. We found that although frequency-current graphs generated by passing 1-s current pulses in neuron somata were non-linear, peak and steady-state graphs of frequency against membrane potential were linear, with slopes of 5.2 and 2.9 Hz/mV, respectively. Systems analysis of impulse frequency adaptation revealed a static threshold nonlinearity at -43 mV (impulse threshold) and a single time constant (tau = 88 ms). This simple model accurately predicts motoneuron impulse frequency when tested by intracellular injection of sinusoidal current. We investigated electrical coupling within motoneurons by modeling these as three-compartment structures. This model, combined with the membrane potential-impulse frequency relationship, accurately predicted motoneuron impulse frequency from intracellular records of soma potentials obtained during fictive swimming. A corollary result was that the product of soma-to-neurite and neurite-to-soma coupling coefficients in leech motoneurons is large, 0.85, implying that the soma and neurite are electrically compact.

A scheme for assuring lifelong readability in computer based medical records.

Medical records must be kept over an extended period of time, meanwhile computer based medical records are renewed every 5-6 years. Readability of medical records must be assured even though the systems are renewed by different vendors. To achieve this, we proposed a method called DACS, in which a medical record is considered as an aggregation of documents. A Document generated by a system is transformed to a format read by free software such as PDF, which is transferred with the document meta-information and important data written on the XML to the Document Deliverer. It stores these data into the Document Archiver, the Document Sharing Server and the Data Warehouse (DWH). We developed the Matrix View which shows documents in chronological order, and the Tree View showing documents in class tree structure. By this method all the documents can be integrated and be viewed by a single viewer. This helps users figure out patient history and find a document being sought. In addition, documents' data can be shared among systems and analyzed by DWH. Most importantly DACS can assure the lifelong readability of medical records.

Multivariable harmonic balance analysis of the neuronal oscillator for leech swimming.

Biological systems, and particularly neuronal circuits, embody a very high level of complexity. Mathematical modeling is therefore essential for understanding how large sets of neurons with complex multiple interconnections work as a functional system. With the increase in computing power, it is now possible to numerically integrate a model with many variables to simulate behavior. However, such analysis can be time-consuming and may not reveal the mechanisms underlying the observed phenomena. An alternative, complementary approach is mathematical analysis, which can demonstrate direct and explicit relationships between a property of interest and system parameters. This paper introduces a mathematical tool for analyzing neuronal oscillator circuits based on multivariable harmonic balance (MHB). The tool is applied to a model of the central pattern generator (CPG) for leech swimming, which comprises a chain of weakly coupled segmental oscillators. The results demonstrate the effectiveness of the MHB method and provide analytical explanations for some CPG properties. In particular, the intersegmental phase lag is estimated to be the sum of a nominal value and a perturbation, where the former depends on the structure and span of the neuronal connections and the latter is roughly proportional to the period gradient, communication delay, and the reciprocal of the intersegmental coupling strength.

Multivariable Harmonic Balance for Central Pattern Generators.

The central pattern generator (CPG) is a nonlinear oscillator formed by a group of neurons, providing a fundamental control mechanism underlying rhythmic movements in animal locomotion. We consider a class of CPGs modeled by a set of interconnected identical neurons. Based on the idea of multivariable harmonic balance, we show how the oscillation profile is related to the connectivity matrix that specifies the architecture and strengths of the interconnections. Specifically, the frequency, amplitudes, and phases are essentially encoded in terms of a pair of eigenvalue and eigenvector. This basic principle is used to estimate the oscillation profile of a given CPG model. Moreover, a systematic method is proposed for designing a CPG-based nonlinear oscillator that achieves a prescribed oscillation profile.

Analytical insights into optimality and resonance in fish swimming.

This paper provides analytical insights into the hypothesis that fish exploit resonance to reduce the mechanical cost of swimming. A simple body-fluid fish model, representing carangiform locomotion, is developed. Steady swimming at various speeds is analysed using optimal gait theory by minimizing bending moment over tail movements and stiffness, and the results are shown to match with data from observed swimming. Our analysis indicates the following: thrust-drag balance leads to the Strouhal number being predetermined based on the drag coefficient and the ratio of wetted body area to cross-sectional area of accelerated fluid. Muscle tension is reduced when undulation frequency matches resonance frequency, which maximizes the ratio of tail-tip velocity to bending moment. Finally, hydrodynamic resonance determines tail-beat frequency, whereas muscle stiffness is actively adjusted, so that overall body-fluid resonance is exploited.

Corrections to the theory and the optimal line in the swimming diagram of Taylor (1952).

The analysis of undulatory swimming gaits requires knowledge of the fluid forces acting on the animal body during swimming. In his classical 1952 paper, Taylor analysed this problem using a 'resistive-force' theory. The theory was used to characterize the undulatory gaits that result in the smallest energy dissipation to the fluid for a given swim velocity. The optimal gaits thus found were compared with data recorded from movies of a snake and a leech swimming. This report identifies and corrects a mathematical error in Taylor's paper, showing that his theory applies even better to animals of circular cross section.

Muscle function in animal movement: passive mechanical properties of leech muscle.

We investigated passive properties of leech body wall as part of a larger project to understand better mechanisms that control locomotion and to establish mathematical models that predict such dynamical behavior. In tests of length-tension relationships in 2-segment-long preparations of body wall through step-stretch manipulations (step size = 1 mm), we discovered that these relationships are nonlinear, with significant hysteresis, even for the relatively small changes in length that occur during swimming. We developed a mathematical model comprising three nonlinear springs, two in series with nonlinear dashpots that describe well the tension statics and dynamics for step-stretch experiments. This model suggested that body wall dynamics are slow enough to be neglected when predicting the tension generated by imposed sinusoidal length changes (about +/-10% of nominal) at 1-3 Hz, mimicking swimming. We derived a static model, comprising one nonlinear spring, which predicts sinusoidal data accurately, even when preparations were exposed to serotonin (0.1-10 microM). Preparations bathed in saline-serotonin had significantly reduced steady-state and peak tensions, without alterations in tension dynamics. Anesthetizing preparations (8% ethanol) reduced body wall tension by 77%, indicating that passive tension in the obliquely striated longitudinal muscles of leeches results primarily from a resting tonus.