Biomedical subjects
Publications and source records attributed to M Minami.
Differences in signal intensity involving lobes of the liver were noted in seven cases of liver tumor. The clinical significance and possible cause of these differences in lobar intensity are discussed.
Forty-two patients with hepatocellular carcinoma (HCC) were examined by magnetic resonance (MR) imaging. The presence of tumor was suggested in 41 of 42 cases by a high-intensity area on T2 weighted spin-echo (SE) images with a repetition time (TR) of 1.6 s. Specific findings of HCC such as the presence of a capsule, mosaic pattern, and tumor thrombus in major veins were noted in 10, two, and seven cases, respectively. In six cases the tumor pattern changed from a well-defined mass to an irregular, ill-defined one according to pulse sequence (SE: echo time 35 and 70 ms; TR 1.6 and 0.4 s). In our early experience MR was almost equal to conventional X-ray CT in the detection of main or daughter lesions and in the determination of extent and characterization of HCC.
Four cases of postnecrotic liver scar were examined by dynamic CT or MR imaging or both. Postnecrotic scars appeared as low-density areas on plain CT, showed marked and prolonged enhancement on single level dynamic CT, and became isodense on postcontrast scan. On T2-weighted images, postnecrotic scar were as hyperintense as the spleen. Postnecrotic liver scar is an example of localized attenuation or intensity difference not corresponding to mass lesion. It should be distinguished from mass lesions associated with lobar or segmental attenuation (or intensity) difference of the liver as well as nonmass lesions such as irregular fatty infiltration, radiation hepatitis, and hepatic infarction.
A functional MR study was performed using a 0.064 T permanent magnet MR system. The shoulder joints, elbow joints, hip joints, and knee joints of three volunteers (mean height and weight, 176 cm and 71 kg, respectively) were examined at incremental joint angles in three to eight stages during flexion-extension, abduction-adduction, or pronation-supination movement. Each set of 16 images was obtained in 4 min, 49 s using three-dimensional Fourier transformation methods with gradient echo pulse sequences. The images were evaluated in static mode and sometimes in cine mode. The findings obtained about the physiology of these normal joints was generally compatible with findings previously accumulated in the field of kinesiology. The study suggests that this method can be useful for in vivo study of kinesiology and pathogenesis of diseases and that patients with most types of contracture or deformity can be examined by MR imaging.
The MR and CT appearances of two cases of splenic hamartoma are presented. Computed tomography showed a well demarcated low-density mass without calcification. Dense spreading enhancement was seen in one case on dynamic CT, and prolonged enhancement was noted in both. The masses were demonstrated as areas of isointensity on T1-weighted MR images and of high intensity on T2-weighted images. On gadolinium-enhanced T1-weighted images they were shown as areas of high intensity. Prolonged enhancement on postcontrast CT and MR imaging was a useful finding in differentiation of splenic hamartoma from malignant lesions of the spleen, especially from nodular lesions of malignant lymphoma.
We report a rare case of a bronchogenic cyst presenting as a pleural nodule. CT and MRI demonstrated a well circumscribed, homogeneous lesion located on the pleural surface apart from the mediastinum. It was proven to be a bronchogenic cyst localized between the parietal and visceral pleurae and connected with the mediastinum only through fibrous tissue. Radiologists should be aware that a mediastinal bronchogenic cyst may be located apart from the mediastinum.
We investigated the in vitro effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with or without the addition of linoleic acid (LA), on cell growth and prostaglandin E (PGE) and leukotriene B (LTB) secretion by a human breast cancer cell line (MDA-MB-231). With or without the addition of LA, EPA and DHA suppressed cell growth and thymidine incorporation and reduced the secretion of PGE and LTB. In a univariate analysis, cell growth was significantly associated with both LTB and PGE concentrations when cells were treated with DHA or EPA, independent of the addition of LA. However, multivariate regression analysis showed that cell growth was more closely associated with the PGE concentration rather than the LTB concentration. These data suggest that both EPA and DHA suppress cell proliferation in the MDA-MB-231 cell line by inhibition of the cyclooxygenase rather than the lipoxygenase pathways. However, the exact mechanism underlying the antitumor activity of EPA and DHA remains unclear.
This study investigated the effects of low-dose eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) on the incidence, tumor growth and cell kinetics of a 7,12-dimethylbenz(a)anthracene-induced mammary carcinoma in rats fed either a high-fat (20% corn oil) or low-fat (0.5% corn oil) diet. Low-dose EPA and DHA completely blocked the stimulatory effect of fat on tumorigenesis, as demonstrated by a decreased number of tumors per group and per tumor-bearing rat. While EPA and DHA inhibited cell kinetics as evidenced by a decreased bromodeoxyuridine-labeling index, their inhibitory effects on tumor size and tumor doubling time were not significant. These data suggest that low-dose EPA and DHA inhibit tumorigenesis rather than tumor growth in the high-fat group.
In order to elucidate the behavioral changes related to stroke, ambulatory activity and water drinking were observed in stroke-prone spontaneously hypertensive rats (SHRSP). Age matched male SHRSP and Wistar Kyoto rats (WKY) were subjected to a 12 hour light and dark alternation cycle. Ambulation and drinking activity counts were determined simultaneously with an Ambulo-Drinkometer. Before stroke, ambulation and drinking activity counts in the dark phase (82%) were higher than those in the light phase (18%). Both parameters were well synchronized with the light and dark alternation cycle. With aging, daily ambulation decreased while daily drinking activity increased in SHRSP and WKY. Daily ambulation and drinking activity in 15 and 30 week old SHRSP were greater than those of WKY. It was demonstrated with an Ambulo-Drinkometer that SHRSP undergo specific behavioral changes before the onset of stroke. For instance, the 40-60 week old SHRSP showed significant individual variation in both ambulation and drinking activity. This desynchronization with the light and dark alternation cycle was followed by stroke. Twenty seven autopsies showed 11 cerebral infarctions, 10 cerebral hemorrhage and 6 cerebral hemorrhage with infarctions to be the causes of death.
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Persistent descending mesocolon is an uncommon developmental anomaly which results from failure of fusion of the descending mesocolon with the posterior parietal peritoneum. It is asymptomatic in most cases and rarely causes intestinal obstruction. We report here a case of primary intestinal obstruction complicated by a persistent descending mesocolon. A 66-year-old man without prior laparotomy was admitted with a diagnosis of small bowel obstruction. Pre-operative investigation demonstrated a segmental jejunal stenosis and a persistent descending mesocolon as possible causes of the obstruction. Laparotomy showed that the cause of the obstruction was the jejunal stenosis, not the persistent descending mesocolon. The stenosis was resected, but correction of the anomaly was not performed. The patient made an uneventful recovery after the operation. From our limited experience, persistent descending mesocolon need not be surgically corrected when it is not considered to be the cause of obstruction and another definite cause co-exists.
In this study, we developed an electrophysiological technique for the in vitro measurement of isolated abdominal vagus nerve depolarization in the rat. This technique was used to compare abdominal and cervical vagus nerve depolarization values. Both 5-HT and a selective 5-HT3 agonist, 2-CH3-5HT, caused a concentration-dependent depolarization in rat isolated abdominal vagus nerves in vitro. Isolated cervical vagus nerves also showed concentration-dependent depolarization, although the isolated cervical vagus nerve depolarization was approximately 60% of that of the isolated abdominal vagus nerves at similar concentration ranges of 5-HT and 2-CH3-5HT in vitro. In isolated abdominal vagus nerves, a selective 5-HT3 antagonist, granisetron, produced a concentration-dependent decrease, but reduced the maximal response of 5-HT-induced depolarization in vitro. In isolated abdominal vagus nerves, selective 5-HT4 antagonist, SB204070, produced parallel and concentration-dependent shifts to the right on the concentration-response curves to 5-HT in vitro. These findings suggest that this electrophysiological method for evaluating isolated abdominal vagus nerve depolarization is a useful technique for the estimation of 5-HT-induced depolarization.
Isatin, an endogenous monoamine oxidase (MAO) inhibitor, has been found in mammalian tissues. We previously reported that exogenously administered isatin significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. In order to elucidate the relationship between isatin and Parkinson's disease, we measured urinary isatin excretions in patients with Parkinson's disease using a newly developed HPLC-UV method. The recovery of this assay was approximately 102.3% at a range from 2 to 50 nmol/ml. The Coefficient of Variance (CV) for the determination at this range was approximately 2.5% for intra-assay and 6.2% for inter-assay, respectively. There was no significant difference in urinary isatin excretion between data from men and women in healthy control. The value in young age group (19-35 years old) was not significantly different compared with that of the older age group (54-84 years old). Urinary isatin levels in patients with Parkinson's disease tended to increase in accordance to the Hoehn and Yahr criteria. This is the first study in which a significant increase in urinary isatin excretion was observed at Stage III, IV and V in patients with Parkinson's disease. Urinary isatin concentrations in drug-treated patients with Parkinson's disease (at Stage I and II) tended to decrease compared with those of patients without medication. These results demonstrated that urinary isatin excretion may serve as an endogenous diagnostic marker for the clinical severity of Parkinson's disease.
In order to elucidate 5-HT release influenced by PGE2 in the background of the anticancer drug-induced emesis, the effect of nabumetone, a COX-2 inhibitor, on the release of 5-HT from the isolated rat ileum was investigated. PGE2 produced a concentration-dependent increase (10(-9) to 10 M) and decrease (10(-8) to 10(-6) M) in 5-HT release. Arachidonic acid also demonstrated a similar bell-shaped 5-HT release. The arachidonic acid-induced 5-HT release at 3 x 10(-6) M (313.04 +/- 25.90%) was significantly inhibited by the concomitant perfusion with BRL10720 (10(-6) M) (161.98 +/- 19.4%, p<0.01), an active metabolite of nabumetone, or indomethacin (3 x 10(-7) M)(190.01 +/- 16.19%, p<0.05). BRL10720 (10(-6) M)(428.57 +/- 51.72%, p<0.05) significantly inhibited the increase in 5-HT release induced by cisplatin (10(-6) M)(748.56 +/- 136.31%), suggesting that PGE2would be involved in cisplatin-induced 5-HT release. The increase in 5-HT release from the isolated ileum 72 hrs after cisplatin administration, in a delayed-emesis animal model, was significantly inhibited by the in vivo 3-day administration of nabumetone or BRL10720, but was not affected by the 3-day administration of dexamethasone. After 72 hours, however, the in vivo 3-days administration of nabumetone, BRL10720 or dexamethasone had no effect on the increase in ileal 5-HT levels induced by cisplatin. The use of COX-2 inhibitors to ameliorate delayed emesis induced by cisplatin-based anticancer chemotherapy has been proposed. On the other hand, there is a possibility that dexamethasone works through a mechanism other than 5-HT release in delayed emesis.
A lipopolysaccharide from Pantoea agglomerans (LPSp) was purified and examined for relief of morphine dependence by observing its inhibition of the jumping of mice on naloxone-precipitate withdrawal. Administration of LPSp either intravenously or intradermally showed marked inhibition of the jumping. Beta-endorphin in mouse serum and brain tissue were recognized to be in synchrony with the time course of the relief. Administration of TNF-alpha gave similar effect, suggesting that LPSp induces a cytokine cascade to produce endogenous TNF followed by ACTH/beta-LPH gene products and beta-endorphin. The effect of LPSp was better than that of LPS from E. coli or Bordetella pertussis, and thus is considered to be applicable for clinical use.
PURPOSE: We compared three-dimensional image (3-D-CT) angiography with conventional angiography to determine the clinical usefulness of this technique. MATERIALS AND METHODS: We studied 15 patients with cerebral aneurysms using dynamic CT with intravenous injection of contrast material and reconstructed 3-D-CT angiography. RESULTS: 3-D-CT angiography could be performed in conjunction with standard axial high-resolution CT without any additional scanning time and within 10-30 minutes for the overall study. All aneurysms were clearly visualized by 3-D-CT angiography. 3-D-reconstruction was very helpful in demonstrating the neck, shape, and direction of aneurysms, and adjacent vascular and bony structures. One small aneurysm that was difficult to detect on axial images was clearly visualized on 3-D-reconstruction. CONCLUSION: 3-D-CT angiography of cerebral aneurysms could be performed routinely and was helpful in demonstrating the complex anatomy of cerebral aneurysms and surrounding structures. This technique will be of value in surgical planning.
A case of hepatocellular carcinoma is reported in which a calculated T2 value of the tumor was exceptionally long and differentiation from cavernous hemangioma based on T2 signal intensity was difficult. Pathologically, the mass consisted of dense, homogeneous acinar formation (pseudoglandular type). The T2 prolongation of the mass was probably due to abundant fluid in the acini.
It is difficult to recognize signal intensity changes on spin echo (SE) images. Clinically both T1-weighted and T2-weighted images are now used in most institutions to evaluate signal intensity changes due to different T1 and T2 of the lesions in MRI. However, these are not sufficient to understand signal intensity changes completely. The authors attempted to summarize on a two-dimensional graph the effects of T1, T2, proton density, and imaging parameters that influence signal intensities on SE images. Both end point (E) and start point (S), as defined later, depended mainly on proton density, but the former also depended on T2 and the later on T1 value. The image obtained in the former situation (near point E) was then called the T2-weighted image. Conditions to accelerate recovery and attenuation velocities (VR and VA), also mentioned later, were the same as those that increased points E and S, respectively. However, when TR was relatively short, the effect of a shorter T1 on VR was greatly emphasized. Such an image was then called the T1-weighted image.