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Biomedical subjects

A Nagata

Publications and source records attributed to A Nagata.

At least 181 records · Page 10Linked to original sources
PubMed1983

[Postirradiation malignant fibrous histiocytoma in a patient with squamous carcinoma of the uterine cervix--an autopsy case].

An autopsy case of postirradiation sarcoma is described. The tumor, a malignant fibrous histiocytoma, occurred in the radiation fied 7 years after postoperative external beam radiation therapy (6000 rad) for squamous cell carcinoma of the cervix. To our knowledge, 11 cases of postirradiation malignant fibrous histiocytoma have been reported in the literature and only one occurrence of this neoplasm after treatment for cervical cancer has been described. We review the literature on postirradiation sarcoma with special attention to malignant fibrous histiocytoma.

Bone Neoplasms↗
PubMed1983

[Phenomenon of a quiet period in the myoelectric amplitudes evoked by H-reflex during voluntary muscle contraction].

The purpose of this study was to analyze the occurrence mechanism of quiet period (silent period, QP) in myoelectric signals of the gastrocnemius muscle by the measure of the electric stimulation with H-reflex, during various background levels of voluntary contraction strength. While surface myoelectric signals of the lateral gastrocnemius muscle in six man subjects with normal neuromuscular functions were recorded during isometric contractions, the tibial nerve was stimulated to evoke H-reflex and subsequent QP. QP was observed invariably in trials with background strength levels of less than 45%MVC (maximum voluntary contraction) starting just after H-wave and lasting 3-120msec. QP occurrence depended upon two neuromuscular factors--low initial strength levels and moderate H-wave amplitudes, and QP duration were changed with the logarithmic relationship according to the initial level of %MVC gradually. From these observation, following conclusions were gotten such as that inhibitory function in the spinal cord was generated to alpha motor neuron from the voluntary contraction and then QP occurrence mechanism should be considered to associate with changes in recurrent inhibition during voluntary contractions by an H-reflex.

Adult↗
PubMed1982

Studies on DNA content of hepatocytes in cirrhosis and hepatoma by means of microspectrophotometry and radioautography.

In order to clarify the underlying mechanism of malignant transformation from cirrhosis to hepatoma the cell kinetics of hepatocytes were studied in these two conditions. The content and synthesis of DNA in hepatocyte nuclei were investigated, by means of Feulgen-microspectrophotometry and tritiated thymidine radioautography, in cirrhotic and noncancerous parts of hepatoma with concomitant cirrhosis. The distribution of ploidy patterns was widely spread, from hypodiploid to hyperpolyploid, in the noncancerous parts of a cirrhotic liver containing hepatoma. In normal liver, each paired nuclear DNA content of a binucleate cell recorded almost the same amount, whereas in the noncancerous as well as in hepatoma cells much difference of DNA content was observed between the paired nuclei of the binucleate cells. The ploidy pattern of hepatocytes in patients with liver cirrhosis, who had developed hepatoma during follow-up periods of several months to several years, appeared to resemble that in noncancerous parts of hepatoma cases. On the other hand, the incorporation of tritiated thymidine into hepatocytes was found to be markedly increased in noncancerous parts as well as in cirrhotic liver developing hepatoma during follow-up periods. These results suggest the possibility that the hepatocytes in noncancerous parts of hepatoma have deranged cell-kinetics which might be a driving factor for the development of malignancy.

Acute Disease↗
PubMed1982

Sixteen years follow-up of a patient with alcoholic pancreatitis: serial findings of morphology and function on the pancreas and the liver.

Sixteen years follow-up was performed in a male of long-standing alcohol indulgence who had an alcoholic liver disease at the outset, followed by alcoholic pancreatitis which progressed finally to pancreatic calcification. During this course, the abnormalities of endoscopic pancreatogram were unremittingly progressive, whereas exocrine and endocrine pancreatic dysfunction remained fluctuating, but ultimately deteriorated. In contrast functional and histological abnormalities of the liver were not progressive but returned toward normal. The follow-up observations in this case suggest that some cases of typical alcoholic pancreatitis may have unremittingly progressive morphologic changes with fairly well reserved capacity of exocrine and endocrine pancreatic functions and their hepatic lesions may not be in parallel with pancreatic lesions.

Adult↗
PubMed1982

A case of acute non-A, non-B sporadic hepatitis with evolution of liver cirrhosis on serial histologic follow-up.

Progression of acute non-A, non-B (NANB) posttransfusion hepatitis to liver cirrhosis has been well recognized as in hepatitis B infection, whereas no progression of acute NANB sporadic hepatitis to liver cirrhosis has yet been documented. We reported a 29-year-old male with prolonged transaminase elevations in whom acute NANB sporadic hepatitis progressed to histologically confirmed cirrhosis during follow-up of about 3 years. It is suggested that some of the cryptogenic cirrhosis of non-B type may develop from acute NANB sporadic hepatitis and long-term observation is also needed in patients with acute hepatitis of this category.

Adult↗
PubMed1982

The significance of blood transfusion in non-A, non-B chronic liver disease in Japan.

We performed a follow-up study on 70 patients with acute non-A, non-B (NANB) posttransfusion hepatitis and a retrospective study on 283 chronic hepatitis, 70 cirrhosis and 53 hepatocellular carcinoma patients of type NANB. In acute NANB post-transfusion hepatitis, as judged by the transaminase levels, th duration of the disease exceeded 6 months in 46/70 = 65.7% and 1 year in 32/70 = 45.7%. The histological diagnosis of the 32 cases persisting for more than 1 year was chronic active hepatitis in 5, chronic persistent hepatitis in 2 and unresolved hepatitis in 6. The frequency of previous transfusion in chronic hepatitis, cirrhosis and hepatocellular carcinoma of type NANB was 42.8, 37.1 and 15.1%, respectively, whereas the incidence of early posttransfusion hepatitis was 8.5, 8.6 and 7.5%, respectively. in chronic liver diseases with a history of jaundice and/or hepatitis, previous transfusions are more frequently associated with type NANB than with type B disease. The present study demonstrates that NANB posttransfusion hepatitis tends to develop to chronic liver disease when analyzed prospectively as well as retrospectively.

Adult↗
PubMed1982

Electromyographic manifestations of muscular fatigue.

Analyses of surface electromyogram (EMG) power spectra and integrated EMG (IEMG) were performed during isometric fatigue contraction in eight male subjects. Fatigability was determined as the rate of rise in IEMG as a function of time (IEMG slope coefficient or eta). Results indicated that the IEMG slope coefficient for the biceps brachii at 40% of maximal voluntary contraction (MVC) was approximately nine times greater than that of the soleus. The exponential decay of maximal sustaining time (Ts) as a function of IEMG slope coefficient (Log Ts - = 0.895 x eta + 2.60, r = 0.92, P less than 0.001) during different fractions of MVC suggested a neurophysiological link between fatigability of the biceps and their motor unit (MU) activities which increased in an accelerated fashion. Analyses of mean power frequency (MPF) revealed that there was a significant decline in MPF (43.7 Hz, P less than 0.001) for the biceps brachii. Furthermore, the extent of this decline was correlated with MPF obtained during MVC (r = 0.96, P less than 0.000). This correlation indicated that MUs with higher MPF would fatigue to a greater extent than those with relatively lower MPF. Subsequent analyses of MPF during fatigue for the soleus revealed that there was a relatively small decline in MPF (7.3 Hz, P greater than 0.05). It was suggested that non-invasive analyses of power spectra and IEMG slope coefficient could provide a sensitive measure of MU fatigability that may reflect the activities of different types of muscle fibers.

Adult↗
PubMed1982

[Frequency analysis (FFT) of electromyography and development of the quiet period in the masticatory muscle discharge].

The purpose of this study was to analyze the control mechanism of quiet period (silent period, QP) in myoelectric signals of the masseter and the anterior part of temporalis by the measure of frequency analysis (FFT) and the power spectra, according to the bite force developement. Surface myoelectric signals of te masseter and the temporalis (both sides) of nine human subjects with normal occlusion were recorded during biting movements. Subjects were asked to increase their forces rapidly to their maximum bite force levels at the decided three rate (0.5sec, 1.0sec and 2.0sec) respectively. QPs (duration; 10 approximately 70ms) were observed (occurrence rate; 44%) almost simultaneously in four muscles at both experimental conditions of the high accelerative movements (0.5sec) and of low levels of bite force remarkably. Frequency analyses were carried out by means of Fast Fourier Transform about myoelectric signals for the period of each 50ms before and after QP occurrence. In the higher frequency bands (200 approximately 480Hz), power spectra "AFTER QP" were distributed with high energy density, whereas "BEFORE QP" were characterized in low frequency bands (20 approximately 180Hz) with low energy. By these analysis, following results were discussed such as that the recruitment of phasic motor units (high frequency bands of power spectra) appeared with fast rate coding in the EMG of QP occurrence, and it should be natural for the neural switching mechanism to be activated in QP occurrence in order to transfer from tonic units to phasic ones of EMG.

Adult↗
PubMed1981

The validity of anaerobic threshold determination by a Douglas bag method compared with arterial blood lactate concentration.

Using an open circuit system (Douglas bag method), measurement of the anaerobic threshold (AT) was performed on ten healthy male college students during an incremental exercise test on a bicycle ergometer in an attempt to determine the validity of this method as compared with arterial blood lactate AT measurement. Blood samples were taken from either the radial or brachial artery through a Teflon catheter (3 ml/each time) every minute until the subject's maximal exercise tolerance was reached. Blood lactate was analyzed by the enzymatic method. Differences in work rate, VO2, %VO2max, VE, HR, and R at ATLA(AT determined by the increase in blood lactate) and at ATGE (gas exchange AT based on the non-linear increases in VE, VCO2, and other respiratory parameters), respectively, were all found to be statistically insignificant. There was a significant correlation (r = 0.866, p less than 0.01) between ATLA and ATGE when expressed i VO2 values (l/min). There was also a significant correlation between ATLA and VO2max (r = 0.778, p less than 0.01). These results indicate that the commonly used Douglas bag method could provide a valid non-invasive measure of anaerobic threshold.

Acidosis↗