Biomedical subjects

Hiroki Takada

Publications and source records attributed to Hiroki Takada.

12 recordsLinked to original sources

PubMed2007

Difficulty in diagnosing autoimmune pancreatitis by imaging findings.

BACKGROUND: Autoimmune pancreatitis (AIP) presents as diffuse enlargement of the pancreas and as diffuse irregular narrowing of the main pancreatic duct. However, some AIP cases are difficult to diagnose because of atypical imaging findings. OBJECTIVE: To clarify a variety of imaging findings of AIP and the reason for its misdiagnosis. DESIGN: We examined the imaging findings of 37 AIP cases and also examined misdiagnosed cases of AIP to determine their reasons for misdiagnosis. PATIENTS: A total of 37 patients with AIP who reported to our hospital or its affiliate over a 17-year period (1989 to May 2005). RESULTS: Patients in 15 AIP cases showed segmental narrowing of the main pancreatic duct. There were 6 patients with focal enlargement of the pancreas, whereas 3 patients showed no enlargement. There were 3 cases of calcification of the pancreas. Pancreatic cysts were detected in 2 patients. Abdominal US showed multiple low-echoic masses in 1 case and a single mass in 3 cases. Sixteen patients had stenosis of the bile duct at the hilar hepatic lesion and/or the intrahepatic duct. Only 7 patients had typical AIP findings. Six patients were misdiagnosed with pancreatic cancer and 2 with bile-duct cancer. Seven cases were surgically treated. Five cases were misdiagnosed because of the nonexistence of, or the unfamiliarity with, the concept of AIP and sclerosing cholangitis with AIP. Another 3 cases were diagnosed with pancreatic cancer because of segmental stenosis of the main pancreatic duct and no or focal enlargement of the pancreas. CONCLUSIONS: The results of this study suggest that AIP presents a variety of imaging findings. The most important diagnostic factor is clinician awareness of the concept of AIP and the diverse nature of imaging findings.

Autoimmune Diseases↗

PubMed2005

Systemic extrapancreatic lesions associated with autoimmune pancreatitis.

OBJECTIVES: Autoimmune pancreatitis (AIP) is often associated with systemic extrapancreatic lesions. We studied 31 cases of AIP to clarify the diversity of associated systemic extrapancreatic lesions and the differences between AIP with and without systemic extrapancreatic lesions. METHODS: The clinical features and courses were compared by age, sex, and blood chemistry between those with and without systemic extrapancreatic lesions. In addition, we reviewed the available literature on systemic extrapancreatic lesions with AIP. RESULTS: Seven of the 31 cases of AIP had associated systemic extrapancreatic lesions, which were diagnosed simultaneously with AIP; however, 1 case presenting with various extrapancreatic lesions was diagnosed independently of the AIP lesion. Patients with systemic extrapancreatic lesions needed maintenance steroid therapy for AIP in 4 cases and systemic extrapancreatic lesions in 2 cases; the ratio of cases requiring maintenance steroid therapy was significantly higher among those with systemic extrapancreatic lesions (6/8) than those without (7/23). There were no significant differences between groups with regard to age, sex, extent of narrowing of the main pancreatic duct, and enlargement of the pancreas. gamma-globulin, IgG, and IgG4 levels were significantly higher in patients with AIP with systemic extrapancreatic lesions than those without. The systemic extrapancreatic lesions associated with AIP found in the literature were Sjögren syndrome, ulcerative colitis, retroperitoneal fibrosis, sialadenitis, thyroiditis, and idiopathic thrombocytopenic purpura. CONCLUSIONS: The results of this study suggest that, when encountering a case of AIP with elevated levels of gamma-globulins, IgG, and IgG4, an effort should be made to detect other systemic extrapancreatic abnormalities and initiate steroid administration.

Aged↗

PubMed2005

Intensive cycle training with artificial gravity maintains muscle size during bed rest.

INTRODUCTION: The present study aimed to investigate the effect of intensive cycle training with short-arm centrifuge-induced hypergravity during bed rest on muscle size and function. METHODS: This study involved 10 healthy men who were divided into 2 groups: a countermeasure group, BR-CM (n = 5); and a control group, BR-Cont (n = 5). The BR-CM subjects partook in intensive cycle training (to 90% of maximum HR) with short-arm centrifuge-induced artificial gravity on alternate days during 20-d bed rest. Muscle volume of the thigh and maximum voluntary contraction (MVC) during isometric knee extensions was measured before and after bed rest. Muscle functional magnetic resonance imaging (mfMRI) and electromyogram (EMG) of the quadriceps femoris were obtained during submaximal knee extension exercises at a load of 30% MVC. RESULTS: The volume of the total thigh muscles was maintained in the BR-CM group (-1%), whereas it was not in the BR-Cont group (-9%, p < 0.05). MVC decreased in the BR-CM (7%) and BR-Cont groups (23%). EMG activity in the BR-CM group after bed rest was significantly lower than that of before; however, no significant change was found in the BR-Cont group. There were no significant changes in the resting and exercised mfMRI signals in either the BR-CM or BR-Cont groups. CONCLUSION: These results suggest that intensive cycle training with hypergravity maintained the size of human skeletal muscles during bed rest.

Adult↗

PubMed2004

Acceleration with exercise during head-down bed rest preserves upright exercise responses.

INTRODUCTION: This study was designed to elucidate the effect of short-arm centrifuge-induced artificial gravity with exercise training during ground-based simulated spaceflight, i.e., prolonged head-down bed rest (HDBR), on respiratory and cardiovascular responses to upright exercise. METHODS: There were 10 healthy men who underwent 20 d of -6 degrees HDBR, and were assigned to either a countermeasure (CM) group (n = 5) or a no countermeasure (No-CM) group (n = 5). The subjects in the CM group performed two sessions (20 min each session, 40 min total) of short-arm centrifuge-induced artificial gravity with exercise training in a supine position on alternate days (10 d total) during HDBR. The first session was set at 0.8-1.4 G load at heart level with a constant exercise intensity (60 W), and the second session began with a 0.3 G load at heart level with an interval exercise protocol (40-80% peak oxygen uptake; VO2peak). The measurements of respiratory and cardiovascular responses to incremental exercise were performed pre- and post-HDBR. RESULTS: The 20 d of HDBR increased minute expired ventilation, heart rate, and respiratory exchange ratio and decreased stroke volume during submaximal exercise in the No-CM group, whereas these parameters were unchanged in the CM group. In the No-CM group, VO2peak decreased significantly (47.0 +/- 8.6 to 34.8 +/- 6.8 ml x kg(-1) x min(-1), p < 0.05), whereas VO2peak in the CM group did not show a significant decrease following 20 d of HDBR (47.7 +/- 10.0 to 43.9 +/- 8.9 ml x kg(-1) x min(-1)). These results suggest that short-arm centrifuge-induced artificial gravity with exercise training is effective in maintaining respiratory and cardiovascular responses to upright exercise.

Adolescent↗

PubMed2004

Effect of centrifuge-induced artificial gravity and ergometric exercise on cardiovascular deconditioning, myatrophy, and osteoporosis induced by a -6 degrees head-down bedrest.

We have reported that centrifuge-induced artificial gravity with ergometric exercise could reduce developing cardiovascular deconditioning in humans. In the present study, we examined this load could prevent the myatrophy and osteoporosis induced by head-down bedrest for 20 days. Subjects were ten healthy male volunteers with informed consent. They were requested to lie down at -6 degrees for 20 days, and evaluation for cardiovascular deconditioning, myatrophy, and osteoporosis. As the result, high G-load with low intensity exercise suppressed the orthostatic intolerance and increase in serum osteoporotic marker, whereas low G-load with high intensity ergometric exercise maintained the maximal oxygen intake, heart dimension, and prevented myatrophy. The combination of high/low G-load with low/high intensity exercise will determine the optimal protocol for prevention of cardiovascular deconditioning, myatrophy, and osteoporosis.

Adult↗

PubMed2003

Adenosquamous carcinoma of the jejunum.

Primary adenosquamous carcinomas of the intestine are rare, particularly in the small intestine. One case, in the jejunum of an adult female, is described here. The patient was a 70-year-old Japanese woman presenting with upper abdominal pain. Computed tomography of the abdomen showed a mass in the small intestine, measuring 86 x 44 mm, and a double-contrast barium study revealed a filling defect in the upper jejunum. The patient was diagnosed as suffering from upper small-intestinal cancer, and surgical excision was performed. Histological examination, including immunohistochemistry and electron microscopy, revealed the tumor to have both malignant glandular and squamous components. A review of the literature regarding this type of lesion is presented.

Aged↗

PubMed2003

An attempt at preventing asthenopia among VDT workers.

We report the results of 3 surveys of visual display terminal (VDT) users who took a minibreak during which they viewed a stereoscopic image of a repeating parallel pattern showing planets. The single image stereogram method employed is called Stretch Eye (TM), and we evaluated the effects of Stretch Eye (TM) on asthenopia. An accommodative relaxation of about 1 D was observed in participants while they were gazing at the image. The employees of 2 information technology companies were evaluated according to a visual analogue scale (VAS) for subjective symptoms of asthenopia and eyesight. The results showed that Stretch Eye (TM) was effective in easing visual fatigue due to VDT work and it improved eyesight under working conditions.

Asthenopia↗

PubMed2003

Analysis of sex, age and disease factors contributing to prolonged life expectancy at birth, in cases of malignant neoplasms in Japan.

BACKGROUND: This study aimed to examine the contribution made by the change in mortality from malignant neoplasms to the life expectancy at birth, observed during the years 1965-1995 in Japan. METHODS: We used data on the population and number of deaths by cause, age and sex in 1965, 1975, 1985 and 1995. The contribution of different ages and causes of death to the change in life expectancy were examined with the method developed by Pollard. RESULTS: We found that, among all causes, the decrease of mortality from stomach cancer led to the greatest improvement in life expectancy for both sexes. On the other hand, negative contributions were seen with cancers of many sites, such as cancer of the intestine, liver and lung for males, and cancer of the intestine, gallbladder, lung and breast for females. Recently, the contributing years of all cancers have been negative because of the increase in mortality from malignant neoplasms. In addition, increase of death from malignant neoplasms in middle-aged and elderly people negatively influenced the life expectancy at birth. CONCLUSIONS: Female cancer influenced the improvement in life expectancy at birth. Cancer for males, however, contributed little to improvement of life expectancy at birth except for a little prolongation of life expectancy at birth during the years 1965-1975. To develop a public health policy, the contributing years to life expectancy at birth can be a useful indication in evaluating the impact of death from various diseases. It is necessary to analyze the contribution made by various causes of death to the changes of life expectancy at birth.

Adolescent↗

PubMed2003

[Efficacy of integrated backscatter imaging by acoustic densitometry for identifying ultrasonic tissue characterization of left ventricular thrombus: two case reports].

Echocardiography demonstrated a high echoic lesion(6 x 5 mm) in the apex of the left ventricle of a 72-year-old man(Case 1) and similar lesions(7 x 6 mm and 4 x 3 mm) in the apex of the left ventricle of a 60-year-old man(Case 2). The amplitude of cyclic variation of integrated backscattering of the high echoic lesions was measured by acoustic densitometry to be lower than that of the myocardium in Case 1, but similar to that of the myocardium in Case 2. Contrast echocardiography detected the perfusion defect of the high echoic lesion in Case 1, but not in Case 2 in the apical four-chamber view. These findings showed that the high echoic lesion indicated thrombus in Case 1, and papillary muscle in Case 2. Measurement of the amplitude of the time intensity curve with contrast echocardiography showed that the amplitude of thrombus was different from that of myocardium. This method is useful for ultrasonic tissue characterization.

Aged↗

PubMed2002

Increasing myocardial 123I-BMIPP uptake in non-ischemic area in a patient with acute myocardial ischemia.

The subject was a 65-year-old woman with chest pain. An electrocardiogram revealed T-wave-inversion in leads III, aVF, V1-V5. 99mTc-tetrofosmin myocardial SPECT showed mildly reduced uptake in the anteroseptal wall and the apex. These findings suggested acute myocardial ischemia. Coronary angiography did not show any stenotic lesions, but diffuse coronary ectasia was noted in three vessels. Coronary flow velocity was remarkably reduced on coronary angiography. Epicardial coronary spasm was not provoked by ergonovine loading test. Left ventriculography showed diffuse hypokinesis. 123I-BMIPP myocardial SPECT showed mildly reduced uptake in the anteroseptal wall and the apex on the early images. But 4-hour delayed images showed an increase of 8% in myocardial 123I-BMIPP uptake. We treated this patient with ticlopidine and nicorandil. After drug therapy her symptoms and left ventriculography improved. 123I-BMIPP myocardial SPECT findings on the early images improved, whereas delayed images showed a decrease of 28% in myocardial 123I-BMIPP uptake after two weeks and 36% after four weeks. These dynamic changes in 123I-BMIPP findings might be a reflection of myocardial fatty acid metabolism in patients with acute myocardial ischemia. Delayed 123I-BMIPP myocardial SPECT images are useful for the assessment of fatty acid metabolism.

Acute Disease↗

PubMed2002

Influence of death from circulatory diseases on life expectancy at birth in Japan.

This study aims to evaluate the contribution of the change in circulatory diseases mortality to the life expectancy at birth observed during the years 1955-1995 in Japan. We used data on the population and the number of deaths by cause, age, and sex in 1955, 1965, 1975, 1985, and 1995. The contribution of different ages and causes of death to the change in life expectancy were examined with the method developed by Pollard. We found that the reduction in circulatory diseases mortality contributed to the improvements in life expectancy for both sexes during the decade 1975-1985. Much of this was due to the decrease in cerebrovascular disease. In the years 1985-1995, however, the contribution of cerebrovascular disease decreased in both sexes, while that of heart disease grew to become the largest of any single condition. By age, the contribution of all circulatory diseases increased among the elderly in recent years. The contribution of the change in circulatory diseases mortality to the life expectancy at birth has increased in recent years but seems to have reached a plateau. The weight against improvements in life expectancy in middle-aged people has shown little change, so that reducing the mortality rate in middle-aged people is now a major issue.

Adolescent↗

PubMed2002

Effects of graded load of artificial gravity on cardiovascular functions in humans.

An artificial gravity and ergometric exercise loading device for human use was manufactured. It has the capacity of a max 2 G-load at the heart level, and a max 150 W of work-load. Eight subjects (six completed) were subjected to four repeated trials with or without 20 W ergometric exercise. Anti-G score, defined as the G-load x running time to the endpoint, was significantly higher in the exercise trials than standing trials. Heart rate (HR), mean arterial pressure (MAP), thoracic fluid index (TFI) were significantly superior during the exercise trials. Artificial gravity by centrifuge at 1.2 or 1.4 G with 40 or 60 W of ergometric workload may be an excellent countermeasure against cardiovascular deconditioning after long exposure to microgravity.

Adult↗