Biomedical subjects
T Kiryu
Publications and source records attributed to T Kiryu.
Band-suppressed restoration of X-ray images blurred by body movement.
The restoration of X-ray images that have been blurred due to body movement are discussed. The observation system for these images is described using a mathematical model, and several restoration filters composed of a series of such models are proposed. These filters restore band-suppressed approximations of the original images. In addition, redundancy is introduced into these restoration filters in order to suppress additive noise. These filters are expanded to be applicable not only to parallel translations, but also to rotations by coordinate transformation. The proposed methods are applied to blurred X-ray images of a bone model of the elbow joint. The parameters of the restoration filter are estimated using a marker attached to the subject as a reference signal.
Multiple chondromatous hamartomas of the lung: a case report and review of the literature with special reference to Carney syndrome.
BACKGROUND: Multiple chondromatous hamartomas of the lung, which are very rare, are a feature of Carney syndrome. The relation between the two entities is not clear. METHODS: A patient with multiple chondromatous hamartomas of the lung is described in this article. The literature was reviewed with special reference to the relation between multiple chondromatous hamartomas of the lung and Carney syndrome as well as the triad of gastric epithelioid leiomyosarcoma, functioning extra-adrenal paraganglioma, and pulmonary chondroma. RESULTS: A total of 15 cases of multiple chondromatous hamartomas of the lung have been published worldwide. Two cases exhibited two other features of Carney syndrome, namely, gastric leiomyogenic neoplasms and extra-adrenal paragangliomas, and three other cases demonstrated only gastric leiomyomatous neoplasms. These five patients were all young females. CONCLUSIONS: Some patients with multiple chondromatous hamartomas of the lung have a history of Carney syndrome. Patients with multiple chondromatous hamartomas require further examination of other sites, particularly the stomach and nervous system.
[Case of intestinal pseudo-obstruction associated with hypothyroidism].
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A muscular fatigue index based on the relationships between superimposed M wave and preceding background activity.
A practical muscle fatigue index is studied in this paper using the correlation between the instantaneous frequencies (IF's) of the superimposed M wave and the mean power frequency (MPF) of the preceding background activity. A superimposed M wave is an M wave elicited during a sustained contraction and was recently introduced for studying muscle fatigue. We investigated the details of the distribution of a feature vector (mpf, if) in two-dimensional space. Our experimental results showed that MPF and IF's were closely correlated during the first phase of a short-term high-level sustained voluntary contraction and then became uncorrelated or sometimes showed negative correlation as muscular fatigue progressed. Combining the correlation coefficients and conventional myoelectric (ME) parameters, such as the MPF and the average rectified value of ME signals, we propose a fuzzy rule based muscular fatigue index that can be used for managing the inevitable variability among individual subjects collected as a group. Introducing fuzzy inference seemed effective, but further studies including detailed investigation of the level of voluntary effort, the muscle fiber type composition, and metabolic by-products will be needed to customize the membership functions and fuzzy rules more appropriately in each practical field.
Multivariate analysis of muscular fatigue during bicycle ergometer exercise.
The purpose of this study is to estimate the endurance threshold in terms of muscular fatigue during bicycle ergometer exercise. The problems to be solved are induced by dynamic movement and the physiological variation of muscle activity: that is, the progression and impairment of muscle activity occur simultaneously. First of all, we used multichannel recordings of myoelectric (ME) signals to reduce the effect by the movement of a bipolar surface electrode relative to the innervation zones. Second, since even the different types of ME parameters contain redundant information on muscular fatigue, we used the principal component analysis (PCA) to represent the meaningful information by small dimensions. Moreover, we proposed a total evaluation pattern to discriminate muscular fatigue from progression of muscle force at a glance. The total evaluation pattern shows the proportion of first principal component, the components of the first eigenvector, and the correlation coefficients as a function of the work load. The assessment using the total evaluation pattern divided eight subjects into three groups, whereas these subjects were not identified by a specific ME parameter.
Multivariate analysis of multichannel surface myoelectric signals to determine muscular fatigue.
Multivariate analysis would be effective in finding the functional change from several variables obtained from multivariate biological signals. We applied this idea to the discrimination of sustained fatiguing contraction from negative ramp contraction. The time-series of eigenvalues were obtained from multidimensional biological variables by the Karhunen-Loève expansion. The results showed that, the first and second eigenvalues came close to each other during fatiguing contraction, whereas only the first eigenvalue was dominant during negative ramp contraction. Moreover, the factor loadings showed considerable difference between fatiguing contraction and negative ramp contraction. As a result, the muscular-fatigue-related functional change could be represented clearly by the time-series of proportions and factor loadings.
Direct evidence of the production of IgA by tonsillar lymphocytes and the binding of IgA to the glomerular mesangium of IgA nephropathy patients.
Tonsils were obtained by tonsillectomy from a 33-year-old woman with IgA nephropathy. Hetero-hybridoma cells of human tonsillar B-lymphocytes with mouse myeloma cells (NS-1) were made, and cultured in HAT medium supplemented with 10% fetus bovine serum and hybridoma cloning factor. The culture medium was analyzed by Western blot analysis using anti-human IgA antibody, and both IgA1 and IgA2 were demonstrated to be produced. The specimens of the biopsied kidney tissue of IgA nephropathy were washed with 0.02 M citrate buffer (pH 3.2) to remove deposited IgA from glomerulus. The specimens were then incubated with the culture media of hybridoma cells, and immuno-fluorescence analysis using FITC-conjugated anti-human IgA antibody was performed. IgA deposit was efficiently removed by washing with citrate buffer and was recovered after incubation with the culture medium of hybridoma cells. Direct evidence of binding of IgA produced by tonsillar B-lymphocytes to the glomerular mesangium of IgA nephropathy was demonstrated.
[Spontaneous regression in a case of primary pulmonary lymphoma with Sjögren's syndrome].
A 62-year-old asymptomatic woman had a nodular shadow approximately 3 cm in diameter in the middle lung field on chest roentgenogram. The shadow gradually grew over 1.5 years. She was then admitted to our hospital for evaluation of the abnormal shadow. Transbronchial biopsy specimens showed a diffuse, small, lymphoid infiltrate with predominance of B-cells. These findings suggested neoplastic proliferation. Further examinations revealed the presence of Sjögren's syndrome. Four months later, she was readmitted for surgical resection. Chest roentgenogram on the second admission disclosed that the mass shadow had shrunk slightly. Histopathological examination of the resected specimen led to the diagnosis of malignant lymphoma, diffuse small cell type (IgG kappa type). Gene analysis revealed the presence of heavy chain gene rearrangements, which confirmed the diagnosis of B-cell lymphoma. In this case, no contraction or necrosis of the lesion was observed, and the change in the shadow size was probably due to partial or transient spontaneous regression.
Bacteria invading periapical cementum.
The aim of this study was to determine whether microorganisms invade periapical cementum of human teeth from the adjacent periapical lesions. We therefore attempted to isolate microorganisms from periapical cementum through the adoption of standard anaerobic procedures for obligate anaerobes. Samples of cementum were taken from 10 amputated tooth roots at the time of apicoectomy. From two of these samples, bacteria were recovered after anaerobic incubation, but no bacteria were recovered after aerobic incubation of the same samples. Of a total of eight isolates from the cementum, seven were obligate anaerobes and one was aerotolerant. The obligate anaerobes isolated were assigned to the genera Prevotella, Peptostreptococcus, Eubacterium, and Fusobacterium. The aerotolerant anaerobe was Campylobacter. From this, we conclude that bacteria can successfully invade cementum via periapical periodontal tissue, and that such bacteria may play a significant role in chronic periapical pathosis.
AR modeling of myoelectric interference signals during a ramp contraction.
We investigated the time-varying behaviour of the autoregressive (AR) parameters in a myoelectric (ME) signal detected during a linear force increasing contraction. The AR parameters of interest were the reflection coefficients, the AR model spectrum, and the prediction errors. We used well-conditioned ME signals for which the complete time record of the motor units firings was available. In addition, the influence of the recruitment of a new motor unit, the conduction velocity of action potentials, and additive broad-band noise were investigated using simulated ME signals. The simulated ME signals were constructed from a selected group of the available motor unit action potential trains. The results revealed that, as the contraction progressed, the AR parameters displayed a time-varying behavior which coincided with the recruitment of newly recruited motor units whose spectrum of the waveform differed from that of the rest of the ME signal. This property of the AR parameters was obscured by the presence of broad-band noise and low-amplitude motor unit action potentials, both of which are more pronounced during low-level force contractions.
[A case of psittacosis with prolonged lymphocytosis in bronchoalveolar lavage fluid after resolution of pneumonia].
A 52-year-old man was admitted to another hospital with complaints of fever and dyspnea. Chest roentgenogram revealed bilateral widespread infiltrative opacities, and laboratory examinations showed severe hypoxia, hepatic injury and acute renal failure. In addition, hemosputum and eruption appeared, and he was transferred to our department because of the development of multi-organ failure. Moreover, about 2 weeks prior to admission, a budgerigar he had been breeding died. Although the treatment was supportive therapy alone, the abnormal shadow on chest roentgenogram and laboratory findings improved markedly. Thereafter, we made the diagnosis of psittacosis, because the serum titer of a complement fixation test against Chlamydia rose from 1:8 on admission to 1:512 after 2 weeks. On admission, PMN and lymphocyte populations increased in bronchoalveolar lavage fluid (BALF), and 2 weeks later lymphocytes alone increased markedly. Thereafter, we observed lymphocytosis in serial BALF findings for 12 weeks. These findings indicate that lymphocyte alveolitis persisted long after the pneumonia had resolved. Moreover, Ga scintigraphy also revealed accumulation in the filed of shadows which had been absorbed and disappeared on the chest roentgenogram. These results suggest that lymphocytes play a leading role in immune host defenses and that immunological reactivity is prolonged in psittacosis.
[Autopsy case of amyloidosis with marked cardiac and pulmonary lesions associated with myeloma, initially presenting with muscle weakness].
A 69-year-old man presented initially with muscle weakness of the bilateral lower limbs. Chest roentgenogram showed diffuse reticulonodular shadows, bilateral hilar lymphadenopathy, and dullness of bilateral costophrenic angles. Chest CT showed thickening and irregularity of vascular shadows, and thickening of bronchial walls. On the first admission we could not diagnose pulmonary or muscle lesions. He was subsequently admitted for the deterioration of congestive heart failure, but there was no improvement. Myocardial biopsy demonstrated deposition of amyloid in the cardiac muscular tissue. Autopsy revealed amyloid deposition in pulmonary vasculature, alveolar septal walls and pleura. Amyloid deposition was also recognized systemically in skeletal muscles, lymph nodes, liver, kidney, spleen, stomach, and intestines. We recognized about 20% IgA lambda-positive plasma cells with atypia, and myeloma-associated amyloidosis diagnosed. This case was classified as diffuse alveolar septal form and pleural form of pulmonary amyloidosis. We could find only a few reports of pleural form, which exhibits an interesting distribution.
[A case of status asthmaticus complicated by with pneumoperitoneum during mechanical ventilation therapy].
A 46-year-old woman was admitted to our hospital for a severe asthma attack. On admission, systemic cyanosis was observed, and her consciousness state was drowsy. Arterial blood gas showed severe respiratory acidosis, hypoxia, and hypercapnea, with pH, PaO2, and PaCO2 of 7.163, 29.9 torr and 81.3 torr, respectively. Immediately, mechanical ventilation was commerced but on the third hospital day pneumomediastinum and subcutaneous emphysema appeared, and on the sixth day pneumoperitoneum also appeared. The chest CT scan on the sixth day showed free air around bilateral internal mammary vessels. This indicated that air moved from the mediastinum into the peritoneal cavity through an anterior route, via the sternocostal triangle formed by the xiphoid origins of the diaphragm medially and the costal origins laterally.
A muscle fatigue index based on the relationship between preceding background activity and myotatic reflex response (MRR).
A new index of muscular fatigue was developed using the myotatic reflex response (MRR). The MRR of masseter muscles is evoked by periodical mechanical chin tapping during clenching. The MRR waveform is composed of somewhat synchronized action potentials of muscle fibers. We estimate the change of the MRR waveform due to fatigue using the instantaneous frequency pattern (IFP) with the Hilbert transform. As a result, the features of IFP were different from the monotonic changes that have been observed by the conventional fatigue indices. That is, a plateau IFP was observed ahead of considerable fatigue, whereas the IFP showed a monopeak pattern during other phase of an exercise. Also, the relationship between the preceding background mean power frequency and the instantaneous frequency around the first part of the MRR waveform was nonlinear during the whole process of fatigue. These features may allow us to estimate the degree of fatigue at each time instant. Although the details have not yet been solved, by using the computer simulations one of them seemed to be the alteration of the dominant frequency components. The dominant frequency components may be related to the active muscle fiber types.
Investigation on parametric analysis of dynamic EMG signals by a muscle-structured simulation model.
In the analysis of electromyographic (EMG) signals during dynamic movement, we have proposed an estimation algorithm for the time-varying parameters of an autoregressive model. The parameters correspond to less biased time-varying reflection coefficients. We determined the less biased estimation using a locally quasi-stationary model and named these parameters "k parameters." We estimated k parameters up to the fifth order for the surface EMG signals of a masseter muscle during rapid open-close movement of the lower jaw, a ballistic contraction, and fatigue. According to the results, the time courses of the k parameters displayed remarkable properties. In order to study the behavior of k parameters physiologically, we produced a muscle-structured simulation model based on anatomical and physiological data. The simulation results suggested that the behavior of the third parameter is related to the number of active motor units (MU's) at the shallow layer of a muscle. The detailed recruitment mechanism in terms of the MU's types has not yet been solved. Although further study is required, the parametric analysis using k parameters offers a new perspective for evaluation of muscle dynamics during several movements.
[Production of reactive oxygen species by rat alveolar macrophages. Dissociation between the intracellular and extracellular release of hydrogen peroxide].
In order to clarify the features of reactive oxygen species produced by rat alveolar macrophages (AMs), the concentrations of intracellular and extracellular hydrogen peroxide were measured under various experimental conditions. Intracellular hydrogen peroxide was measured by DCFH method using a flow cytometer, while the extracellularly released fraction was measured by scopoletin method using a spectrophotometer. The concentration of intracellular hydrogen peroxide after stimulation with opsonized zymosan (10 micrograms/ml) was significantly higher than that after stimulation with phorbol myristate acetate (PMA; 100 ng/ml). On the other hand, hydrogen peroxide released extracellularly after stimulation with PMA was significantly greater that that after stimulation with opsonized zymosan. These results indicate that the soluble membrane stimulant and the phagocytic particles have different mechanisms in activating the production of hydrogen peroxide in AMs. That is, hydrogen peroxide induced by PMA was mainly released extracellularly, while that induced by zymosan was mainly released into the intracellular environment. At rest, the concentration of intracellular hydrogen peroxide in rat AMs was high. Potassium cyanate, a known mitochondrial inhibitor, suppressed the intracellular hydrogen peroxide in AMs not only at rest but also after stimulations, indicating that most of the reactive oxygen species released into the intracellular environment in AM are produced by mitochondria. From these results, in order to gain a closer insight into the function of AMs, it is very important to distinguish the oxidative metabolites produced intracellularly which are related to bactericidal function from those of the extracellularly released fraction which give rise to lung damage.
EMG analysis of complete denture wearers using a three-dimensional representation of the time behavior of AR model parameters.
Three-dimensional representation to screen the adaptation process of individual dentures is presented. In the parametric analysis of electromyographic (EMG) signals, we have to deal with the complicated behavior of a lot of parameters in the time domain. We have employed the less-biased time varying AR model parameters estimated by locally quasi-stationary processing. Hence, we propose the time-suppressed representation of the behavior, projecting the time series of less-biased time-varying vectors onto three standard planes. The vector is composed of the k parameters, K(i) for i = 1, 2, 3. Therefore, the mutually perpendicular coordinates are K(1), K(2) and K(3). Significant changes which appear to result from the muscle dynamics are observed in the K(2)-K(3) plane, as the masticatory function is recovered.