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Biomedical subjects

M Kusumoto

Publications and source records attributed to M Kusumoto.

At least 55 records · Page 3Linked to original sources
PubMed1997

A left atrial myxoma complicated with acute myocardial infarction.

A 43-year-old female, admitted because of acute infero-posterior myocardial infarction, showed angiographic findings of 100% occlusion of left circumflex artery. Echocardiographic findings showed inferior hypokinesis, while a large left intraatrial tumor was also observed. The coronary angiography on the 17th hospital day showed complete reperfusion of the culprit lesion without stenosis. On the 21st hospital day, the removal operation of the tumor was performed. Pathological findings showed typical cardiac myxoma, and the etiology of the occlusion at the culprit vessel was presumed to be closely related to the existence of the left atrial tumor.

Adult↗
PubMed1997

Effect of trophic factors on delayed neuronal death induced by in vitro ischemia in cultivated hippocampal and cortical neurons.

The effect of trophic factors on neuronal survival after 30 min oxygen and glucose deprivation (in vitro ischemia) was studied in primary hippocampal and cortical neuronal cultures of rat. In vitro ischemia was produced at 37 degrees C by placing cultures in glucose-free medium, the oxygen content of which was removed by gassing with pure argon. After in vitro ischemia neurons were allowed to recover either in serum-free minimal essential medium (MEM) or in MEM containing 5% native horse serum, 100 ng/ml basic fibroblast growth factor (bFGF) or 10 ng/ml transforming growth factor-beta 1 (TGF-beta 1), respectively. Cultures that recovered in serum-free medium suffered a progressive type of neuronal injury: survival of either cortical or hippocampal neurons declined from about 60% after 1 h to 50% after 3 h, 40% after 6 h and less than 20% after 24 h. Addition of serum proteins to the incubation medium did not influence early survival (up to 3-6 h) but significantly improved survival after 24 h (more than 40% in both hippocampal and cortical cultures). Addition of TGF-beta 1 and bFGF had only minor effects. These data show that serum reduces delayed ischemic cell death by a mechanism which is different from that of TGF-beta 1 or bFGF protection.

Animals↗
PubMed1997

[The role of CT and MR imaging in the diagnosis of lung cancer].

CT and MR imaging can play an important role in the diagnosis of lung cancer. Evaluation of a solitary pulmonary nodule is usually carried out using CT. High-resolution CT is useful in the morphologic diagnosis of a solitary pulmonary nodule. The enhancement characteristics of a pulmonary nodule in contrast-enhancement CT can be a method of distinguishing benign and malignant nodules. MR imaging is superior to CT in contrast resolution and multidirectional imaging capability. Contrast-enhancement MR imaging can describe the enhancement characteristics of the pulmonary lesion better than contrast-enhancement CT. The extent of chest wall and mediastinal invasion of lung cancer can be better shown using MR imaging than CT.

Adenocarcinoma↗
PubMed1997

[Evaluation of therapeutic effect using enhanced MRI in lung cancer: evaluation of methods in terms of necrosis].

To evaluate therapeutic effect in terms of necrosis or cavity, enhanced MRI was performed in 40 lung cancer patients treated by conservative therapy. We provided the reduction ratio of the viable tumor as calculated by a volume method and a cross-sectional method. In the volume method, the volume of necrosis was subtracted from the volume of the tumor, and in the cross-sectional method, the product of the longest diameter and widest perpendicular diameter of necrosis was subtracted from the product of the longest diameter and widest perpendicular diameter of the tumor. We then examined whether we could substitute the cross-sectional method for the volume method. The reduction ratios of viable tumor calculated by the two methods were in good correlation. The limits of agreement of each method and their repeatability coefficients were considered small enough for clinical use. Therefore, we concluded that the cross-sectional method could be used in place of the volume method for clinical purposes. In evaluating therapeutic effect in terms of necrosis when using contrast-enhanced MR imaging, the reduction ratio of the viable tumor determined by the cross-sectional method can be substituted for that determined by the volume method.

Aged↗
PubMed1996

Serum prevents glutamate-induced mitochondrial calcium accumulation in primary neuronal cultures.

The effect of serum proteins on glutamate-induced mitochondrial calcium accumulation was studied in primary cortical and hippocampal cultures using oxalate-pyroantimonate staining with electron microscopy. Cultures were prepared from rat embryos on gestational day 17-19 and cultivated for 8 days in minimal essential medium (MEM) containing 5% native horse serum. At this time cultures were exposed for 5 min to 100 micro M or 1.0 mM glutamate, followed by recovery in either serum-free or serum-containing culture medium. Mitochondrial calcium accumulation was assessed before glutamate treatment, at the end of glutamate exposure, and after 5 min, 30 min, 6 h and 24 h of recovery. Under control conditions and at the end of glutamate exposure, mitochondria contained only a few calcium deposits. If cultures were placed in serum-free medium after glutamate treatment, mitochondria were progressively loaded with calcium. At 5 min after glutamate exposure mitochondrial calcium deposits were prominent in both cortical and hippocampal cultures, followed by a further steady increase and neuronal death within 24 h. When cultures were allowed to recover after glutamate treatment in serum-containing MEM, calcium sequestration and ultrastructural changes of mitochondria were essentially absent, and neurons survived. No differences between cortical and hippocampal cultures were observed. The data demonstrate that prevention of glutamate neurotoxicity by serum proteins is associated with prevention of post-glutamate mitochondrial calcium accumulation.

Animals↗
PubMed1996

Early ultrastructural changes after brief histotoxic hypoxia in cultured cortical and hippocampal CA1 neurons.

Primary cortical and hippocampal neuronal cultures submitted to brief histotoxic hypoxia suffer delayed neuronal death after 24 h [Uto et al. (1995) J Neurochem 64: 2185-2192]. In this study the ultrastructural changes were monitored during the first 6 h following 5-min histotoxic hypoxia induced by exposure to 100 microM iodoacetate. In both cortical and hippocampal CA1 neurons, disaggregation of ribosomes was the earliest sign of histotoxic pathology. Vacuolizations of mitochondria, endoplasmic reticulum and Golgi apparatus, as well as fragmentation and disintegration of neurofilaments followed later. Signs of apoptotic nuclear degeneration were absent. Our observations demonstrate that, similar to that seen in ischemia, disaggregation of ribosomes after brief histotoxic hypoxia is one of the first pathological alterations heralding delayed neuronal death.

Animals↗
PubMed1996

Susceptibility of hippocampal and cortical neurons to argon-mediated in vitro ischemia.

Neurons from cerebral cortex and hippocampal CA1 sector exhibit a striking difference in vulnerability to transient ischemia. To establish whether this difference is due to the inherent (pathoclitic) properties of these neurons, the ischemic susceptibility was studied in primary cortical and hippocampal cultures by using a new model of argon-induced in vitro ischemia. Neuronal cultures were exposed at 37 degrees C for 10-30 min to argon-equilibrated glucose-free medium. During argon equilibration, Po2 declined to < 2.5 torr within 1 min and stabilized shortly later at approximately 1.3 torr. After 30 min of in vitro ischemia, total adenylate was < 45% and ATP content < 15% of control in both types of culture. Cytosolic calcium activity increased from 15 to 50 nM. Reoxygenation of cultures after in vitro ischemia led to delayed neuronal death, the severity of which depended on the duration of in vitro ischemia but not on the type of neuronal cultures. Energy charge of adenylate transiently returned to approximately 90% of control after 3 h, but ATP content recovered only to 40% and protein synthesis to < 35%. Cytosolic calcium activity continued to rise after ischemia and reached values of approximately 500 nM after 3 h. The new argon-induced in vitro ischemia model offers major advantages over previous methods, but despite this improvement it was not possible to replicate the differences in cortical and hippocampal vulnerability observed in vivo. Our study does not support the hypothesis that selective vulnerability is due to an inherent pathoclitic hypersensitivity.

Adenine Nucleotides↗
PubMed1996

[Three-dimensional reconstruction images of central airway using spiral CT: experimental and clinical studies in the demonstrability of tracheobronchial lesions].

The purpose of this study was to evaluate the role of three dimensional reconstruction image using spiral CT (3D image) for demonstrating the tracheobronchial lesions. In the experimental study using originally developed phantom, 3D images of simulated endobronchial protrusions were evaluated at combinations of detector collimation (1, 3 and 5 mm), table speed (1, 2, 3 and 5 mm/sec) and reconstruction pitch (1 and 3 mm). 3D images with 1 mm collimation, 1 mm/sec table speed, and 1 mm reconstruction pitch (1/1/1) could provide the best demonstrability of simulated endobronchial protrusions. But the condition (1/2/1) is not so inferior to 1/1/1. The stair-step artifacts were caused by the effects of rotation and aliasing, which could be reduced with slow table speed and fine reconstruction pitch. In clinical study, 3D images (1/2/1) were applied in 34 patients with hilar lung cancer and these images were compared with bronchoscopic findings. 3D images demonstrated irregular obstructions or stenoses in 15 of 16 cases with mucosal lesions, 5 of 7 cases with submucosal lesions with mucosal invasion. On the other hand, in 4 cases with submucosal lesions without mucosal invasion and 6 of 7 cases with intramural or extramural lesions, smooth stenoses were demonstrated on 3D images. In 30 of 34 cases (88.2%), 3D images corresponded to bronchoscopic findings. In conclusion, 3D images proved useful in demonstrating not only the obstructions or stenoses of central airway, but also mucosal irregularity. 3D-CT could be helpful for determining indication for transbronchial biopsy of hilar lung cancer.

Adult↗
PubMed1995

Resistance to cerebral ischemia in developing gerbils.

Two-, three-, four-, five-, and twelve-week-old gerbils were subjected to various periods of bilateral carotid occlusion (BCO). Rectal and cranial temperatures were maintained at 37 degrees C during BCO, and only rectal temperature was monitored for 30 min of reperfusion. Seven days after ischemia, animals were perfusion-fixed and the neuronal densities in the hippocampal CA1 subfields were counted. The extent of cerebral ischemia during BCO was evaluated with [14C]iodoantipyrine autoradiography. The rectal temperature spontaneously fell to 33-34 degrees C during reperfusion in 2-week-old gerbils, although animals over 3 weeks old presented postischemic hyperthermia. Two-week-old animals therefore were divided into three experimental groups: In one group (2-week-old group I) rectal temperature was not regulated during 30 min of reperfusion, while in the other two groups (2-week-old groups II and III) rectal temperature was regulated at 37 and 38 degrees C, respectively, during reperfusion. Five-minute BCO produced almost complete destruction of the CA1 neurons in 12-week-old animals. In contrast, most CA1 neurons survived 30 min of BCO in 2-week-old group I and 15 min of BCO in 2-week-old groups II and III. [14C]Iodoantipyrine autoradiography revealed that BCO produced severe forebrain ischemia in 2-week-old gerbils as well as in 12-week-old gerbils. These findings indicate that developing gerbils have a greater tolerance to cerebral ischemia and that such ischemic tolerance is not due to a collateral network between the vertebrobasilar and the carotid circulations previously reported to develop more abundantly in developing gerbils.

Aging↗
PubMed1995

Delayed neuronal death after brief histotoxic hypoxia in vitro.

The effect of three metabolic inhibitors--iodoacetate, potassium cyanide, and potassium arsenate--on neuronal viability was studied in primary rat cortical and hippocampal CA1 neuronal cultures. Iodoacetate (0.1 mM) applied for 5 min to 8-day-old cultures resulted in delayed neuronal death within 3-24 h in cortical and hippocampal CA1 neurons. Neuronal degeneration was preceded by transient inhibition of energy metabolism to approximately 40% and a permanent inhibition of protein synthesis to approximately 50%. The inhibition of protein synthesis and the neuronal death were prevented by the free radical scavenger vitamin E but not by the glutamate antagonist MK-801. Removal of calcium during iodoacetate exposure could not protect against toxicity, and there was no increase of intracellular calcium concentration during and shortly after iodoacetate treatment. Cyanide and arsenate produced only partial neuronal degeneration, even at a dose of 10 mM. These observations demonstrate that brief exposure of neurons to low concentrations of iodoacetate produces a delayed type of neuronal death that is not mediated by either calcium or glutamate. The therapeutic effect of vitamin E points to a free-radical mediated injury and suggests that this type of pathology may also be involved in delayed neuronal death after transient energy depletion in vivo.

Adenine Nucleotides↗
PubMed1995

[Assessment by three-dimensional CT of pleural indentation or invasion by peripheral lung cancer].

We evaluated the effectiveness of three-dimensional (3D) CT for pleural indentation or invasion by peripheral lung cancer adjacent to pleura. Pleural indentation was shown in three of nine cases on conventional CT, and six cases were demonstrated three-dimensionally. 3D-CT was superior to conventional CT in demonstrating pleural indentation. Pleural invasion could not be assessed on 3D-CT because the pleura adjacent to the tumor was not visualized.

Humans↗
PubMed1995

[Evaluation of photon-counting X-ray radiography for the detection of pulmonary nodule: a preliminary report on experimental and clinical studies].

To evaluate the utility of photon counting X-ray radiography (quantum radiography: QR) for the detection of pulmonary nodules, experimental and clinical studies were performed in comparison with conventional X-ray (CXR). In the experimental study, spatial resolution was analyzed by using the micro-chart method. The simulated nodule detection study was performed by using a chest phantom. The results were evaluated by means of ROC analysis. In the clinical study, both images of CXR and QR were evaluated in a case of metastatic lung tumor. In the experimental study, the spatial resolution of QR was 200 microns. QR was superior to CXR in detecting simulated nodules in all areas. In clinical cases, QR was superior to CXR in depicting not only normal structures but also retrocardiac and retrodiaphragmatic pulmonary nodules.

Carcinoma, Renal Cell↗
PubMed1994

[Protective effects of KC-764 on short-term forebrain ischemia in gerbils].

KC-764, developed as a cyclo-oxygenase inhibitor, was administered to gerbils in a dose of 10 mg/kg, i.p., before subjecting them to 5-minute bilateral forebrain ischemia in order to determine whether it would have any protective effects. No post-ischemic hyperthermia (over 39 degrees C for 120 min) was observed in the KC-764 group. Behavior recovery time after ischemia was 11.4 +/- 2.8 minutes in the KC-764 group versus 87.3 +/- 13.4 minutes in the control group (p < 0.05). Delayed neuronal death (DND) in the CA1 region of the hippocampus was inhibited in the KC-764 group, but when the KC-764-treated animals were exposed to hyperthermia, the degree of DND was the same as in the control group. EEG voltage recovery time in the CA1 region of the hippocampus was almost the same in the control group, the KC-764 group, and the KC-764-plus-hyperthermia (HT) group. Although tissue blood flow measurements in the CA1 region of the hippocampus showed post-ischemic hypoperfusion (81 +/- 18% of the pre-ischemic level at 60 minutes), it was prevented in the KC-764 group (102 +/- 21%) (p < 0.05) and the KC-764-plus-HT group (96 +/- 28%). There was a tremendous increase in PGD2 (1461.4 +/- 863.4 p mol/g) and PGF2 alpha (219.6 +/- 104.2 p mol/g) in the forebrain after 5 minutes of reflow, but this increase in prostaglandin levels was inhibited (p < 0.05) in the KC-764 group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Clinical utility of computed radiography (CR) for the diagnosis of lung cancer].

To clarify the clinical utility of computed radiography (CR) for the diagnosis of lung cancer, several kinds of image-processed CR images were compared with conventional radiographs (CXR). The images in the three patients with peripheral lung cancer were processed by the following six types: 1) processing close to CXR (plain CR), 2) wide latitude and high frequency emphasis (wide CR), 3) advanced high frequency emphasis (HE-CR), 4) lower frequency emphasis (LE-CR), 5) single exposure dual energy subtraction (ES) and 6) ES with lower frequency emphasis (LE-ES). In the two cases of hilar lung cancer, 1) plain CR, 2) wide CR, 3) CR tomographs similar to CXR tomographs (plain CR-TOMO) and 4) high frequency emphasized CR tomographs (HE-CR-TOMO) were processed. Twenty-six radiologists rated the image-processed CR images using a 5 point rating scale method. The following results were found for the evaluation of lung anatomy: almost all image-processed CR images were equal or superior to CXR; especially scores for plain CR were better than those for CXR in all anatomical structures studied; scores for ES were superior to those for plain CR in the bilateral main bronchi, left upper lobe bronchus and right paratracheal stripe; and scores for CR tomographs were better than those for CXR tomographs. In peripheral lung cancer, plain CR and ES were superior to CXR. Especially ES had the best scores. In hilar lung cancer, plain CR and CR tomographs were judged better than CXR and CXR tomographs. These findings indicate the usefulness of CR images for the diagnosis of lung cancer.

Aged↗
PubMed1993

[A study of the utility of the MR image for the diagnosis of thymic tumors--imaging and pathologic correlation].

MR imaging was performed in 25 patients with thymic tumors (five with non-invasive thymomas, 15 with invasive thymomas, and five with thymic carcinomas), and the MR imaging appearance was compared with the pathological findings. Non-invasive thymomas showed generally oval or round masses with well-defined margins and homogeneous intensity on T1- and T2-weighted images. Invasive thymomas showed a multinodular appearance in 79% (11/15) of cases, and an internodular difference in signal intensity (IDSI) in 64% (7/11) on T2-weighted images. It was considered that the IDSI on T2-weighted images correlated pathologically with the hemorrhagic and/or necrotic areas and hyalinization. The IDSI seemed to be a characteristic finding of invasive thymomas. The histological findings and MR imaging appearance of thymomas were compared. The predominantly epithelial type showed a low incidence of nodular appearance but showed marked IDSI on T2-weighted images. Therefore, it is more likely that the predominantly epithelial type induced more varied intratumoral changes than other types. Extension of thymic carcinomas was similar to that of invasive thymomas on MR imaging, but thymic carcinomas showed no definite nodular appearance. In conclusion, MR images in thymic tumors were useful for not only determining the morphology of the tumor but also the tissue characteristics. Therefore, MR imaging can be a useful modality to correlate with the histological findings and biological behavior of thymic tumors.

Adult↗
PubMed1993

Clinical utility of Gd-DTPA-enhanced magnetic resonance imaging in lung cancer.

Magnetic resonance (MR) imaging has both advantages and disadvantages in its application in lung cancer staging. Because of its ability to provide superior contrast resolution and to display structures in many planes, MR imaging is better than computed tomography (CT) for the detection of mediastinal and chest wall invasion. MR imaging also is more sensitive than CT for detection of hilar and mediastinal lymph node enlargement. Multiplanar T1- and T2-weighted images are optimal for differentiating lymph nodes from large vessels without the need for contrast enhancement; in these cases administration of Gd-DTPA provides no more information than plain MR images. MR studies should be used for examining patients with suspected mediastinal or chest wall invasion and those who have equivocal hilar or mediastinal adenopathy. The shortening effect of Gd-DTPA on the T1 value results in a high signal. This effect is dependent upon both the perfusion and diffusion of the contrast agent and the amount of extracellular fluid. The distribution of Gd-DTPA is similar to that of iodinated water-soluble contrast media. Gd-DTPA examination should be tailored to provide information regarding blood flow, vascularity, and permeability, none of which is easily appreciated on CT or plain MR images. Applications for which Gd-DTPA enhancement may be helpful include differentiating between malignant and benign pulmonary masses, differentiating between hilar lung cancer and peripheral postobstructive atlectasis or pneumonia, determining therapeutic effect after radiation therapy, and differentiating between recurrent or residual tumor and radiation pneumonitis.

Diagnosis, Differential↗