Dynamic causal model application on hierarchical human motor control estimation in visuomotor tasks

Introduction

In brain function research, each brain region has been investigated independently, and how different parts of the brain work together has been examined using the correlations among them. However, the dynamics of how different brain regions interact with each other during time-varying tasks, such as voluntary motion tasks, are still not well-understood.

Methods

To address this knowledge gap, we conducted functional magnetic resonance imaging (fMRI) using target tracking tasks with and without feedback. We identified the motor cortex, cerebellum, and visual cortex by using a general linear model during the tracking tasks. We then employed a dynamic causal model (DCM) and parametric empirical Bayes to quantitatively elucidate the interactions among the left motor cortex (ML), right cerebellum (CBR) and left visual cortex (VL), and their roles as higher and lower controllers in the hierarchical model.

Results

We found that the tracking task with visual feedback strongly affected the modulation of connection strength in ML → CBR and ML↔VL. Moreover, we found that the modulation of VL → ML, ML → ML, and ML → CBR by the tracking task with visual feedback could explain individual differences in tracking performance and muscle activity, and we validated these findings by leave-one-out cross-validation.

Discussion

We demonstrated the effectiveness of our approach for understanding the mechanisms underlying human motor control. Our proposed method may have important implications for the development of new technologies in personalized interventions and technologies, as it sheds light on how different brain regions interact and work together during a motor task.

Forearm muscle activity estimation based on anatomical structure of muscles

Estimation of muscle activity using surface electromyography (sEMG) is an important non-invasive method that can lead to a deeper understanding of motor-control strategies in humans. Measurement using multiple active electrodes is necessary to estimate not only surface muscle activity but also deep muscle activity in dynamic motion. In this paper, we propose a method for estimating muscle activity of dynamic motions based on anatomical knowledge of muscle structures. To estimate muscle activity, a large number of signal sources are set in the muscle model, and connections between the signal sources are defined a priori based on the anatomical structure of the muscles. The signal source activities are first estimated by minimizing the Kullback-Leibler divergence with a continuity cost. Then, the muscle activity is computed from the signal source activity. In the experiments, five healthy participants performed five types of motion and the forearm sEMG was measured with 20-channel active electrodes. The estimation results for these motions were visualized in four dimensions as the three-dimensional position of the muscle over time. The results showed that the estimation was accurate, with a reproduction rate of 95% for the measured sEMG and continuity of the muscle activity. In addition, the results suggest the advantage of the proposed method over the conventional approaches in terms of estimating the muscle activity for both dynamic and abnormal motions.

Artifact removal from sEMG signals recorded during fully unsupervised daily activities

Objective

In this study, we propose a method for removing artifacts from superficial electromyography (sEMG) data, which have been widely proposed for health monitoring because they encompass the basic neuromuscular processes underlying human motion.

Methods

Our method is based on a spectral source decomposition from single-channel data using a non-negative matrix factorization. The algorithm is validated with two data sets: the first contained muscle activity coupled to artificially generated noises and the second comprised signals recorded under fully unsupervised conditions. Algorithm performance was further assessed by comparison with other state-of-the-art approaches for noise removal using a single channel.

Results

The comparison of methods shows that the proposed algorithm achieves the highest performance on the noise-removal process in terms of signal-to-noise ratio reconstruction, root means square error, and correlation coefficient with the original muscle activity. Moreover, the spectral distribution of the extracted sources shows high correlation with the noise sources traditionally associated to sEMG recordings.

Conclusion

This research shows the ability of spectral source separation to detect and remove noise sources coupled to sEMG signals recorded during unsupervised daily activities which opens the door to the implementation of sEMG recording during daily activities for motor and health monitoring.

Quantification of high and low sEMG spectral components during sustained isometric contraction

Superficial Electromyography (sEMG) spectrum contains aggregated information from several underlying physiological processes. Due to technological limitations, the isolation of these processes is challenging, and therefore, the interpretation of changes in muscle activity frequency is still controversial. Recent studies showed that the spectrum of sEMG signals recorded from isotonic and short-term isometric contractions can be decomposed into independent components whose spectral features recall those of motor unit action potentials. In this paper sEMG spectral decomposition is tested during muscle fatigue induced by long-term isometric contraction where sEMG spectral changes have been widely studied. The main goals of this work are to validate spectral component extraction during long-term isometric muscle activation and the quantification of energy exchange between the low- and high-frequency bands of sEMG signals during muscle fatigue.

Model for prompt and effective classification of motion recovery after stroke considering muscle strength and coordination factors

Background

Muscle synergies are now widely discussed as a method for evaluating the existence of redundant neural networks that can be activated to enhance stroke rehabilitation. However, this approach was initially conceived to study muscle coordination during learned motions in healthy individuals. After brain damage, there are several neural adaptations that contribute to the recovery of motor strength, with muscle coordination being one of them. In this study, a model is proposed that assesses motion based on surface electromyography (sEMG) according to two main factors closely related to the neural adaptations underlying motor recovery: (1) the correct coordination of the muscles involved in a particular motion and (2) the ability to tune the effective strength of each muscle through muscle fiber contractions. These two factors are hypothesized to be affected differently by brain damage. Therefore, their independent evaluation will play an important role in understanding the origin of stroke-related motor impairments.

Results

The model proposed was validated by analyzing sEMG data from 18 stroke patients with different paralysis levels and 30 healthy subjects. While the factors necessary to describe motion were stable across heathy subjects, there was an increasing disassociation for stroke patients with severe motor impairment.

Conclusions

The clear dissociation between the coordination of muscles and the tuning of their strength demonstrates the importance of evaluating these factors in order to choose appropriate rehabilitation therapies. The model described in this research provides an efficient approach to promptly evaluate these factors through the use of two intuitive indexes.

Generation of Human-Like Movement from Symbolized Information

An important function missing from current robotic systems is a human-like method for creating behavior from symbolized information. This function could be used to assess the extent to which robotic behavior is human-like because it distinguishes human motion from that of human-made machines created using currently available techniques. The purpose of this research is to clarify the mechanisms that generate automatic motor commands to achieve symbolized behavior. We design a controller with a learning method called tacit learning, which considers system–environment interactions, and a transfer method called mechanical resonance mode, which transfers the control signals into a mechanical resonance mode space (MRM-space). We conduct simulations and experiments that involve standing balance control against disturbances with a two-degree-of-freedom inverted pendulum and bipedal walking control with humanoid robots. In the simulations and experiments on standing balance control, the pendulum can become upright after a disturbance by adjusting a few signals in MRM-space with tacit learning. In the simulations and experiments on bipedal walking control, the robots realize a wide variety of walking by manually adjusting a few signals in MRM-space. The results show that transferring the signals to an appropriate control space is the key process for reducing the complexity of the signals from the environment and achieving diverse behavior.

Dispersion interferometer using modulation amplitudes on LHD (invited)

Since a dispersion interferometer is insensitive to mechanical vibrations, a vibration compensation system is not necessary. The CO2 laser dispersion interferometer with phase modulations on the Large Helical Device utilizes the new phase extraction method which uses modulation amplitudes and can improve a disadvantage of the original dispersion interferometer: measurement errors caused by variations of detected intensities. The phase variation within ±2 × 10(17) m(-3) is obtained without vibration compensation system. The measured line averaged electron density with the dispersion interferometer shows good agreement with that with the existing far infrared laser interferometer. Fringe jump errors in high density ranging up to 1.5 × 10(20) m(-3) can be overcome by a sufficient sampling rate of about 100 kHz.

Development of CO2 laser dispersion interferometer with photoelastic modulator

A dispersion interferometer is one of the promising methods of the electron density measurement on large and high density fusion devices. This paper describes development of a CO(2) laser dispersion interferometer with a photoelastic modulator for phase modulation. In order to make the dispersion interferometer free from variations of the detected intensity, a new phase extraction method is introduced: The phase shift is evaluated from a ratio of amplitudes of the fundamental and the second harmonics of the phase modulation frequency in the detected interference signal. The proof-of-principle experiments demonstrate the feasibility of this method.

Development of two color laser diagnostics for the ITER poloidal polarimeter

Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 μm by using a twin optically pumped CH(3)OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.

Short wavelength far infrared laser polarimeter with silicon photoelastic modulators

A short wavelength far infrared laser whose wavelength lambda is about 50 microm is preferable for a polarimeter and an interferometer for high density operations in the Large Helical Device (LHD) and on future large fusion devices such as ITER. This is because the beam bending effect (proportional to lambda(2)) in a plasma, which causes fringe jump errors, is small and the Faraday and the Cotton-Mouton effects are moderate. We have developed a polarimeter with highly resistive silicon photoelastic modulators (PEMs) for the CH(3)OD laser (lambda=57.2 and 47.7 microm). We performed bench tests of the polarimeter with a dual PEM and demonstrated the feasibility for the polarimeter. Good linearity between actual and evaluated polarization angles is achieved with an angular resolution of 0.05 degrees and a temporal resolution of 1 ms. The baseline drift of the polarization angle is about 0.1 degrees for 1000 s.

Detection of high k turbulence using two dimensional phase contrast imaging on LHD

High k turbulence, up to 30 cm(-1), can be measured using the two dimensional CO2 laser phase contrast imaging system on LHD. Recent hardware improvements and experimental results are presented. Precise control over the lens positions in the detection system is necessary because of the short depth of focus for high k modes. Remote controllable motors to move optical elements were installed, which, combined with measurements of the response to ultrasound injection, allowed experimental verification and shot-to-shot adjustment of the object plane. Strong high k signals are observed within the first 100-200 ms after the initial electron cyclotron heating (ECH) breakdown, in agreement with gyrotron scattering. During later times in the discharge, the entire k spectrum shifts to lower values (although the total amplitude does not change significantly), and the weaker high k signals are obscured by leakage of low k components at low frequency, and detector noise, at high frequency.

Two-dimensional phase contrast imaging for local turbulence measurements in large helical device (invited)

Two-dimensional phase contrast imaging (2D) installed on the large helical device (LHD) is a unique diagnostic for local turbulence measurements. A 10.6 microm infrared CO(2) laser and 6x8 channel HgCdTe 2D detector are used. The length of the scattering volume is larger than plasma size. However, the asymmetry of turbulence structure with respect to the magnetic field and magnetic shear make local turbulence measurements possible. From a 2D image of the integrated fluctuations, the spatial cross-correlation function was estimated using time domain correlation analysis, then, the integrated 2D k-spectrum is obtained using maximum entropy method. The 2D k-spectrum is converted from Cartesian coordinates to cylindrical coordinates. Finally, the angle in cylindrical coordinate is converted to flux surface labels. The fluctuation profile over almost the entire plasma diameter can be obtained at a single moment. The measurable k-region can be varied by adjusting the detection optics. Presently, k=0.1-1.0 mm(-1) can be measured which is expected region of ion temperature gradient modes and trapped electron mode in LHD. The spatial resolution is 10%-50% of the minor radius.

Development of terahertz laser diagnostics for electron density measurements

A two color laser interferometer using terahertz laser sources is under development for high performance operation on the large helical device and for future burning plasma experiments such as ITER. Through investigation of terahertz laser sources, we have achieved high power simultaneous oscillations at 57.2 and 47.6 microm of a CH(3)OD laser pumped by a cw 9R(8) CO(2) laser line. The laser wavelength around 50 microm is the optimum value for future fusion devices from the consideration of the beam refraction effect and signal-to-noise ratio for an expected phase shift due to plasma. In this article, recent progress of the terahertz laser diagnostics, especially in mechanical vibration compensation by using a two color laser operation and terahertz laser beam transmission through a dielectric waveguide, will be presented.

Changes of optical properties of retroreflector installed in LHD

This article describes changes of optical properties of retroreflectors installed on the inner wall of the vacuum vessel of the Large Helical Device. They were made of stainless steel and were used for a CO(2) laser polarimeter. The reflectivity for a CO(2) laser beam dropped up to 40% after the start of glow discharge cleanings and main plasma experiments. Then it decreased gradually. The reflectivity in a wavelength range shorter than 10 mum decreased significantly through one experimental campaign (about 4 months). On the other hand the reflectivity in a wavelength range longer than 50 mum was larger than 70%. Decrease in the reflectivity in the central region of mirrors was more significant (the reflectivity for visible beams became almost zero) than that in the edge. The distribution of the reflectivity along the radial direction is expected to be related to the shape of the retroreflector. The parallelism of the reflected beam to an incident one also deteriorated. The changes in the polarization angle and in the ellipticity of reflected light polarization were not observed from the visible to the far infrared range.

[Diagnosis of the postoperative local recurrence of rectal cancer by FDG-PET--a case report]

Positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) as the tracer of glucose metabolism was performed to identify a postoperative recurrent lesion of rectal cancer. A 66-year-old-man underwent trans-sacral local resection of the rectum for rectal cancer in 1992. A local recurrent mass was discovered, and abdomino-perineal resection of the rectum was performed in 1999. The serum CEA level increased gradually August in 2000, but there was no sign of recurrence on CT or MRI. FDG-PET was performed to reveal a presacral recurrent lesion. Total pelvic evisceration combined with resection of the sacrum, and a bilateral ureterostomy were performed in April 2001. The beneficial role of FDG-PET in the diagnosis of the postoperative local recurrence of rectal cancer is emphasized.

[A case of recurring breast cancer causing pericardial metastasis showing a good response following local treatment with methotrexate]

A 52-year-old woman was admitted with a chief complaint of dyspnea. She had undergone right mastectomy for Stage IIB breast cancer 2 years and five months earlier. Chest roentgenogram revealed cardiomegaly and bilateral pleural effusion, and a cardiac echogram showed marked retention of pericardial effusion. A diagnosis of cardiac tamponade was made and pericardiocentesis for continuous drainage was carried out cytologically, the effusion was class V and showed evidence of pericardial metastasis of breast cancer. Pericardiocentesis followed by methotrexate instillation 6 times in a dose of 110 mg successfully controlled the cardiac tamponade, after which the catheter could be removed from the pericardial space. Systemic chemotherapy (CEF) was started at the same time. The patient was discharged very much improved after these treatments, but she died of brain metastasis after 9 months. This case suggests that intrapericardial application of methotrexate may be very useful in the management of carcinomatous cardiac tamponade without any serious side effects.

[A patient with esophageal cancer with subcutaneal abscess and esophago-tracheal fistula who survived more than 2 years following treatment by drainage and chemoradiation therapy]

A 48-year-old man presented at the hospital because of neck swelling and pain. A diagnosis of esophageal cancer with subcutaneous abscess was made based on examination and biopsy results. The cancer was Ce T4NxMx Stage III-IVa. Curative surgery was considered impossible, so chemoradiation therapy was performed (5-FU 500 mg + CDDP 5 mg/day + 2 Gy/day x 31 days) after drainage. During the therapy, an esophago-tracheal fistula was observed, but it later vanished. After chemoradiation therapy, the abscess and tumor vanished. No serious adverse reactions were observed. Now, 2 years after therapy, no recurrence has been found. The patient is now in good health with no symptoms and undergoes regular check-ups. Chemoradiation therapy is effective for inoperable advanced esophageal cancer.

Molecular cloning, sequence analysis and expression of a novel gene induced by near-UV light in Bipolaris oryzae

A cDNA clone derived from a novel gene (uvi-1) that is inducible by near-UV light was isolated by a differential screening procedure from a cDNA library of the fungus Bipolaris oryzae and characterized further. Sequence analysis of the clone revealed that uvi-1 encodes a protein with a putative molecular mass of 17 kDa; the UVI-1 protein shows significant similarity to a putative protein encoded by a cDNA which is expressed during appressorium formation in the rice blast fungus, Magnaporthe grisea. The corresponding genomic clone was also isolated, and Southern analysis of genomic DNA indicated the presence of a single copy of the uvi-1 gene in B. oryzae. Northern analysis showed that the uvi-1 transcripts are induced by exposure to near-UV light, but not by blue or red light. Furthermore, accumulation of uvi-1 transcripts is observed during differentiation of the appressorium.

Antenatal dexamethasone administration impairs normal postnatal lung growth in rats

Our purpose was to determine the influences of antenatal dexamethasone administration on neonatal lung development in rats. Dexamethasone (0.4 mg/kg maternal body weight per day) was administered i.p. on the 21st d (group 1) or on the 20th and 21st d (group 2) of gestation in Sprague Dawley rats with timed pregnancies. After natural deliveries, the lungs of the pups 1-60 d of age were removed and processed for morphometric analysis. In 60-d-old pups, groups 1 and 2 both showed a lower numerical density of alveoli and a larger mean alveolar radius than control pups. Antenatal administration of dexamethasone to rats impairs the normal postnatal lung growth. Some aspects of the use of antenatal glucocorticoid therapy in humans may require reconsideration.

Ultrastructural characteristics and synaptophysin immunohistochemistry of regenerating nerve growth cones following traumatic injury to rat peripheral nerve

Growth cones of regenerating nerves, following crush injury to the rat peripheral nerve system, were studied by electron microscopy and synaptophysin. Localization in the growth cones was revealed by immunohistochemistry at the ultrastructural level. Many regenerating growth cones grew along the Schwann-cell basal laminae tubes at the crushed site. These cones revealed an abundance of organelles, such as heterogenous vesicles and many mitochondria, and a scarcity of cytoskeletons, including microtubules and neurofilaments in the cytoplasm. The periphery of the growth cones (corresponding to the lamellipodia or filopodia of cultured neurons) contained rich electron-dense filamentous materials. Cellular protrusions, such as filopodia, were rarely seen. These growth cones exhibited intense immunoreactivity for synaptophysin by light microscopy. Immunoelectron microscopy demonstrated that immunoreactivity was distributed diffusely in the cytoplasm.

[Repetitive chemo-embolization with degradable starch microspheres (DSM) to each left and replaced right hepatic artery in a patient with multiple liver metastases of colon cancer]

In a patient with a right hepatic artery arising from the superior mesenteric artery bearing multiple liver metastases from colon cancer, hepatic arterial chemo-embolization was performed in combination with degradable starch microspheres (DSM) administered independently to the left and replaced right hepatic artery via a percutaneal approach. As the first line chemotherapy from hepatic artery with DSM 300 mg, 5-FU 500 mg and MMC 10 mg resulted in PD. DSM 300 mg, epirubicin (EPI) 50 mg, MMC 4 mg was administered with the RHA:LHA ratio of 3:1 as a second line. Four weeks later it was evaluated as NC by angiography and by tumor-marker dropped extremely. The same regimen was repeated every four weeks, and the NC status remained for 20 weeks in total. Each time, the left and replaced right hepatic artery got perfect re-perfusion and DSM enabled an effective whole liver distribution of anti-cancer drugs and repetitive administrations of them. This regimen could be an alternative choice for patients with a replaced right hepatic artery who have liver metastasis of colon cancer.

Hemodynamic responses to photic stimulation in neonates

A three-channel near-infrared monitoring system was used to evaluate the regional hemodynamic responses to photic stimulation during spontaneous sleep in seven healthy neonates. Three pairs of parallel light guides, separated by 15 mm each, were placed over a 450-mm(2) occipital region of the head. Increases in oxygenated and total hemoglobin were observed during photic stimulation only in one channel, and no change or decreases in oxygenated, deoxygenated, and total hemoglobin were observed in the other two channels. The change in the direction of deoxygenated hemoglobin accompanying the increases in oxygenated and total hemoglobin (usually a decrease in adults) differed in each subject and also varied with each measurement even in the same subject. An increase, decrease, and no change were observed. The results imply that an increase in regional cerebral blood flow occurs because of stimulation specific to the visual cortex and that the increase in deoxygenated hemoglobin observed in the visual cortex of the neonatal brain is attributable to venous dilation.

[A case of locally advanced breast cancer successfully resected after selective intra-arterial chemotherapy]

A 25-year-old female with a large tumor on her left breast was examined at our hospital from August, 1999. Ipsilateral supraclavicular, infraclavicular and axillary lymph nodes were swollen. She was diagnosed as having locally advanced breast cancer of stage IIIb by fine needle aspiration cytology. After the administration of docetaxel (60 mg/m2/3 weeks x 3) failed to improve her condition, we changed the treatment to selective intra-arterial chemotherapy with THP-ADR (60 mg/body/day, day 1 & 8, 41 & 48) by Seldinger's method. The target vessels were the internal thoracic, lateral thoracic, thoracodorsal and deep cervical arteries. We also combined 5-FU 500 mg/body div and CPA 500 mg/body i.v. on the same days with intra-arterial chemotherapy. As a result, the main tumor and metastatic lymph node swelling was remarkably reduced (down-staging was obtained). No recurrence was found for 5 months after curative resection.

[A case of locally advanced rectal carcinoma with liver metastasis treated with a combination of CRT, HAI, and systemic chemotherapy]

A 55-year-old man with locally advanced rectal carcinoma and liver metastasis was treated with a combination of chemo-radiotherapy (5-FU suppository 100 mg/day and 63 Gy of RT), hepatic arterial infusion chemotherapy (5-FU 1,000 mg/3 h, biweekly), and systemic chemotherapy (5'-DFUR 800 mg/day + cimetidine 800 mg/day). His rectal tumor was reduced and his symptoms such as pain and bleeding had markedly decreased. The river metastasis did not change during the entire course. HAI and administration of 5-FU suppository, 5'-DFUR, and cimetidine were continued. As of 18 months after the onset of the combination therapy, NC has been maintained, and the general condition of the patient is favorable.

Factors influencing pulmonary surfactant protein A levels in cord blood, maternal blood and amniotic fluid

The purpose of this study was to evaluate factors that influence pulmonary surfactant protein A (SP-A) levels in cord blood, maternal blood and amniotic fluid, as well as to establish the normal range of serum SP-A. Labor significantly influenced cord blood SP-A levels. The SP-A levels in maternal blood after delivery were correlated with, but higher than those before delivery. There was a correlation between SP-A levels in amniotic fluid and cord blood. Neonatal serum SP-A was not correlated with maternal SP-A levels. The normal range of SP-A in cord blood was 2.7-21.7 ng/ml following cesarean section without labor, 4.8-50.2 ng/ml after labor at gestational weeks 36-38, and 12.2-44.6 ng/ml at gestational weeks 39-41. SP-A levels in maternal blood before and after delivery and amniotic fluid were 6. 0-74.0, 9.6-73.6 and 403.4-24,540 ng/ml, respectively.

VAMP-2 promotes neurite elongation and SNAP-25A increases neurite sprouting in PC12 cells

Recent studies suggest that the soluble N-ethylmaleimide-sensitive factor attached protein (SNAP) receptor (SNARE)-mediated membrane fusion system is involved in vesicle fusion in the plasma membrane that allows expansion for neurite elongation. There have been several reports analyzing the effects of neurite outgrowth by inhibition of SNAREs. In this study, we took the opposite approach by overexpressing green fluorescent protein (GFP)-fusion SNAREs, including VAMP-2, SNAP-25A, and syntaxin1A, in PC12 cells to investigate the role of SNAREs in the neurite outgrowth of PC12 cells. Neurite outgrowth analysis demonstrated that: (1) GFP-VAMP-2 increased the length of individual neurites, without changing the number of neurites per cell; (2) GFP-SNAP-25A increased the number of neurites per cell, with no change in the length of the individual neurites. In both cases, the total length of neurites per cell was increased; (3) GFP-syntaxin1A resulted in no significant change, either in neurite length, or in the number of neurites per cell. These findings suggest that when overexpressed in PC12 cells, VAMP-2 can promote neurite elongation, while SNAP-25A can stimulate neurite sprouting. On the other hand, overexpression of syntaxin1A neither promotes nor inhibits neurite outgrowth. Thus VAMP-2 and SNAP-25A play different roles in neurite elongation and sprouting.

Specific HLA in pulmonary MAC infection in a Japanese population

Patients with pulmonary Mycobacterium avium complex (MAC) infection occasionally have neither past histories of pulmonary diseases nor underlying immunodeficiency conditions. Therefore, we hypothesized that MAC may be linked with a disease-susceptibility gene and determined human leukocyte-associated antigens (HLA) in patients with pulmonary MAC infection. HLA phenotypes were tested in 59 patients with pulmonary MAC infection, and diagnosed according to the criteria of the American Thoracic Society. Data of a Japanese population reported at the Tenth Japan HLA Workshop were used as a control. HLA-A33 (28.8% versus 12.5%, p = 5 x 10(-)(4)) and HLA-DR6 (50.8% versus 20.2%, p = 5 x 10(-)(8)) antigen frequencies in patients with MAC were significantly increased compared with those of the control population. Frequency of a haplotype A33-B44-DR6 in the MAC patients was also significantly increased compared with those of the control population (23.7% versus 4.2%; p = 3 x 10(-)(9)). These data suggest that development of pulmonary MAC infection is associated with specific HLA in a Japanese population.

Ultrastructure of early axonal regeneration in an end-to-side neurorrhaphy model

The ultrastructure of the early regenerative response in an end-to-side neurorrhaphy rat model was studied using transmission electron microscopy. The ipsilateral saphenous nerve was grafted to the sciatic nerve under the following conditions: Group 1, the epineurium and perineurium of the sciatic nerve remained intact; Group 2, an epineurial and perineurial window was created at the site of the lateral neurorrhaphy; Group 3, the same as in Group 2 and, in addition, the sciatic nerve sustained a partial neurectomy. Rats were perfused through the heart with fixative containing 2 percent paraformaldehyde and 2.5 percent glutaraldehyde in 0.1 M cacodylate buffer (pH 7.4) at 4, 8, 12, 24 and 48 hr after surgery. In Group 1, no regenerating axons were observed and the myelin sheath in the donor nerve did not demonstrate any degenerative changes through 48 hr. In Group 2, an increased diameter of the unmyelinated axons and growth cones was observed in the donor nerve proximal to the coaptation site after 12 hr. Degenerative changes in the myelin sheath were observed after 12 hr within the several layers under the coaptation site. In Group 3, many growth cone-like structures were observed in the area proximal to the coaptation site after 12 hr. After 24 hr, proximal regenerating axons elongated to the coaptation site and, at 48 hr, many regenerating nerves grew inside the Schwann cell basement membrane of the graft nerve. These results indicate that the perineurial window and nerve graft are the critical conditions for inciting nerve regeneration in the donor nerve.

Quantitative analysis of neural distribution in human coracoacromial ligaments

This study investigated sensory nerve distribution in 27 human coracoacromial ligaments by immunohistochemical methods using antiprotein gene product 9.5 antibody and anticalcitonin gene related peptide antibody. Mean nerve densities were compared among three areas (acromion side, center, and coracoid side) in two groups (patients with rotator cuff tears and patients with shoulder dislocations). In all three areas of both groups, many nerve fibers immunoreactive to antiprotein gene product 9.5 antibody were observed in the periligamentous bursal tissue. However, in the ligament parenchyma, nerve fibers immunoreactive to antiprotein gene product 9.5 antibody were recognized only around blood vessels. Nerve fibers immunoreactive to anticalcitonin gene related peptide antibody were recognized in the periligamentous bursal tissue. However, in the ligament parenchyma, there were no nerve fibers immunoreactive to anticalcitonin gene related peptide antibody. Nerve density of the rotator cuff tear group, as revealed by both immunostainings, showed a significant increase compared with that of the shoulder dislocation group in all three areas. The results of this study show that it is possible the increase in sensory nociceptive nerve fibers in the coracoacromial ligaments may be one of the causes for pain in patients with rotator cuff tears.

Nerve distribution to the human knee joint: anatomical and immunohistochemical study

The nerve distribution to the knee joints was analyzed in 5 cadavers and 10 joint capsules specimens were resected during total knee arthroplasty. We found nerve fibers immunoreactive for anti-substance P antibody in the articular capsule. By confocal laser scanning microscopy, we evaluated the three-dimensional structures of the Ruffini's corpuscles and the free nerve endings, both of which were immunoreactive for anti-protein gene product 9.5.

Prediction of respiratory distress syndrome by the level of pulmonary surfactant protein A in cord blood sera

The purpose of this study was to determine the utility of measuring the level of pulmonary surfactant protein A (SP-A) in cord blood sera to predict for respiratory distress syndrome (RDS). SP-A levels in cord blood sera from 48 infants born at gestational ages < 32 weeks were measured by a sandwich ELISA system. Mean value of SP-A in cord blood was 5.8 ng/ml in cases with RDS and 15.1 ng/ml in those without RDS (p = 0.002). The best cut-off point of cord blood SP-A to predict RDS was determined as 10 ng/ml. The sensitivity and the specificity of the cut-off point for predicting RDS were 81 and 76%, respectively. Multivariate regression analysis showed that high SP-A level in cord blood, premature rupture of the membranes longer than 24 h and heavy birth weight were all significantly related to the non-RDS outcome.

Relationship between the 137Cs whole-body counting results and soil and food contamination in farms near Chernobyl

We measured the radioactivity in the soil and child food samples from farms near Mogilev (56-270 GBq km(-2) 137Cs), Gomel (36-810 GBq km(-2) 137Cs), and Klincy (59-270 GBq km(-2) 137Cs), who had whole-body 137Cs counting results measured as part of a health examination in the Chernobyl Sasakawa Health and Medical Cooperation Project. Soil contamination on the family farm seems to be the main source of human contamination because most of the people in the area live on small farms and they and their domestic animals eat crops from the farms. A clear correlation was found between the children's whole-body 137Cs counting results and the radioactivity in their food (correlation coefficient: 0.76; confidence level of correlation: 3.2 x 10(-9)). There were also significant correlations between the whole-body 137Cs counting results and both the radioactivity of the soil samples (correlation coefficient: 0.22; confidence level of correlation: 0.0107) and the average contamination level of their current residence (correlation coefficient: 0.20; confidence level of correlation: 0.0174).

Up-regulated uridine kinase gene identified by RLCS in the ventral horn after crush injury to rat sciatic nerves

Rat sciatic nerve crush injury is one of the models commonly employed for studying the mechanisms of nerve regeneration. In this study, we analyzed the temporal change of gene expression after injury in this model, to elucidate the molecular mechanisms involved in nerve regeneration. First, a cDNA analysis method, Restriction Landmark cDNA Scanning (RLCS), was applied to cells in the ventral horn of the spinal cord during a 7-day period after the crush injury. A total of 1991 cDNA species were detected as spots on gels, and 37 of these were shown to change after the injury. Temporally changed patterns were classified into three categories: the continuously up-regulated type (10 species), the transiently up-regulated type (22 species), and the down-regulated type (5 species). These complex patterns of gene expression demonstrated after the injury suggest that precise regulation in molecular pathways is required for accomplishing nerve regeneration. Secondly, the rat homologue of uridine kinase gene was identified as one of the up-regulated genes. Northern blot analysis on rat ventral horn tissue and brain revealed that the UK gene had three transcripts with different sizes (4.3, 1. 4, and 1.35 kb, respectively). All of the transcripts, especially the 4.3 kb one, were up-regulated mainly in a bimodal fashion during the 28-day period after the injury. The RLCS method that we employed in the present study shows promise as a means to fully analyze molecular changes in nerve regeneration in detail.

[Palliative chemo-radiotherapy for abdominal recurrence of esophageal carcinoma--case report]

A 71-year-old man with stage IV esophageal carcinoma was treated by chemo-radiotherapy (5-FU 500 mg/day + CDDP 10 mg/day for 4 weeks and 67.6 Gy of RT). The esophageal tumor showed a complete response to the treatment. Six months later, he had obstructive jaundice due to an abdominal recurrent mass. A secondary (palliative) CRT was performed (5-FU 500 mg/day + CDDP 10 mg/day for 3 weeks and 45 Gy of RT). The abdominal tumor became remarkably smaller and jaundice disappeared. Though the patient died from pulmonary carcinomatous lymphangitis, the primary lesion showed CR. CRT was very effective for local treatment and for palliative therapy.

[Intraperitoneal cisplatinum chemotherapy in patients with carcinomatous peritonitis due to colorectal scirrhous cancer--case report]

Two patients received intraperitoneal cisplatinum chemotherapy for carcinomatous ascites due to colorectal cancer recurrence. The patients were a 47-year-old man who had rectal cancer and 51-year-old woman who had colon cancer. They had received the operation and adjuvant chemoradiation therapy and chemotherapy respectively. However, five months and two years after resection, respectively, they presented massive ascites due to carcinomatous peritonitis and were given cisplatin injection intraperitoneally. The amount of ascites was significantly diminished. One patient had been discharged and been able to stay at home, and the other patient underwent gastrostomy for ileus. The results suggested that intraperitoneal cisplatinum chemotherapy may be useful for the patient with carcinomatous ascites due to colorectal cancer.