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Biomedical subjects

M Koga

Publications and source records attributed to M Koga.

609 records · Page 34Linked to original sources
PubMedDate not supplied

Imaging features of pancreatoblastoma: a case report.

We present a patient with pancreatoblastoma along with a discussion of various cross-sectional imaging features. The tumor was a large multilocular cystic mass with solid components in the left retroperitoneal space. There were fine internal echoes on ultrasonography, and the signal intensity was high on both T1- and T2-weighted MR images in most of the locules, suggesting the presence of hemorrhagic debris. Among the various retroperitoneal organs displaced by the tumor, only the pancreatic tail was inseparable from the mass, suggesting that the pancreatic tail was the origin of the tumor. Pancreatoblastoma should be included in the differential diagnosis when a large left upper quadrant mass with these imaging features is seen in infants and young children.

Child↗
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Hepatocellular carcinoma with ring calcification: report of two cases.

Two cases of hepatocellular carcinoma (HCC) with ring calcification are reported together with their CT findings. HCC in both cases showed little early enhancement followed by delayed enhancement on dynamic CT. The pathologic specimen in one case showed HCC with fairly abundant fibrosis, and calcification was noted underneath the thick fibrous capsule, which might explain the enhancement pattern on CT.

Aged↗
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Microembolic signals and diffusion-weighted MR imaging abnormalities in acute ischemic stroke.

BACKGROUND AND PURPOSE: The clinical significance of microembolic signals (MESs) detected by transcranial Doppler sonography (TCD) in acute ischemic stroke remains unclear. The purpose of the present study was to assess the findings of diffusion-weighted MR imaging (DWI) and other clinical characteristics in patients with acute ischemic stroke and MESs. METHODS: We performed TCD and DWI within 48 hours and 7 days, respectively, after stroke onset in 28 patients with acute brain infarction. The relationship between the number of MESs and DWI findings, risk factors for stroke, National Institutes of Health Stroke Scale (NIHSS) score on admission, and arterial disease was examined. RESULTS: Ten patients had MESs detected by TCD (MES group) and 18 had no MESs (control group). The frequency of hypertension, diabetes mellitus, hyperlipidemia, and smoking; NIHSS score; blood-coagulation parameters; and interval between stroke onset and DWI study did not differ between the two groups. However, arterial disease was more frequent in the MES group than in the control group. Small, multifocal ischemic lesions (<10 mm in diameter) on DWI were more frequent in the MES group than in the control group. Conventional CT and MR imaging often failed to show these lesions. CONCLUSION: Small, often asymptomatic DWI abnormalities were more frequent in patients with MESs detected by TCD and with large-vessel occlusive diseases than in stroke patients without MESs. TCD and DWI may provide early clues to the mechanism of stroke in the acute phase.

Acute Disease↗
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[Anti-GD1b IgG antibody-related Guillain-Barré syndrome initially mimicking brainstem infarction].

We described a 58-year-old woman with Guillain-Barré syndrome, who initially showed rapid progression of brainstem infarction-like signs. She developed superficial sensory disturbance on the left side, dysarthria, and left-predominant limb weakness within a few hours. She showed bilateral extensor plantar responses and head CT scan detected no abnormality. It was difficult to be distinguished from brainstem infarction until symmetrical limb weakness and generalized areflexia appeared. Serum anti-GD1b IgG antibody with cross-reactivity with GM1b was detected. Cerebrospinal fluid examination revealed albuminocytologic dissociation on day 5. After 5 sessions of immunoadsorption therapy, her symptoms gradually lessened. Anti-GD1b antibody has been detected in patients with sensory ataxic neuropathy. Our patient, however, was characterized with early involvement of brainstem with ataxia of cerebellar type. Our case suggests that anti-GD1b antibody-associated neuropathy has a broad spectrum of clinical features, which are related to cross-reactivity of this antibody.

Brain Stem Infarctions↗
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CD8+ T-lymphocytes infiltrate the myocardium in fulminant herpes virus myocarditis.

We report two cases of fulminant viral myocarditis in previously healthy children. They were caused by herpes simplex virus (HSV)-1 (in a boy aged 3 years) and Epstein-Barr virus (EBV) (in a boy aged 12 months). We obtained the diagnosis of HSV-1 myocarditis by immunohistochemistry and the diagnosis of EBV myocarditis by in situ hybridization. Histologic examination of heart tissue from the two boys revealed mononuclear cell infiltration of the myocardium. Immunohistochemical staining identified these cells as CD8+ T-lymphocytes. CD8+ T-lymphocytes induced by herpes virus infections may play an important role in the damage to heart muscle fibers seen in fulminant myocarditis in previously healthy children. To our knowledge, this is the first report of HSV-1 or EBV myocarditis (at least in children) in which viral infection has been demonstrated in the myocardium.

CD8-Positive T-Lymphocytes↗
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Hypogonadism of male prolactinomas: relation to pulsatile secretion of LH.

In order to investigate whether a hypothalamic disorder cause hypogonadism in male prolactinomas, LH pulsatile secretion was studied in 13 male patients. Serum PRL levels ranged from 186 to 45,000 ng ml-1 before treatment, and all the tumors were macroadenomas. Reduced LH secretion was revealed in 5 of 13 patients, and FSH was reduced in 1 of 13. Serum testosterone (T) levels were lower than the normal limit in all the patients. HCG tests in 3 patients showed good responses, but the peak values of T were lower than those of normal men. LH pulsatilities were examined in 5 hyperprolactinemic patients before treatment, in 4 hyperprolactinemic patients after operation, and in 8 normoprolactinemic patients after operation and/or bromocriptine treatment. There was no significant difference of the mean LH values, the frequencies of LH pulses, and amplitudes among the hyperprolactinemic patients before operation (n = 5), the normoprolactinemic patients after operation (n = 8), and normal men (n = 7). From these results, it was evident that the hypothalamus and pituitary function of male prolactinomas were well preserved, in spite of higher serum PRL levels and larger tumor size than those reported in females. It is suggested that the main cause of hypogonadism in these patients is due to testicular dysfunction resulting from excessive serum PRL.

Adult↗
PubMedDate not supplied

Excision of papillary endocardial tumor.

We report the eighth case of surgical removal of a papillary endocardial tumor. The surgical approach was aided by intraoperative two-dimensional echocardiography. The tumor was attached to the chorda tendinea of the mitral valve and was successfully removed via a left atrial approach.

Adult↗
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Renovascular hypertension: a case of intimal fibroplasia with congenital anomaly of the renal artery.

We report a case of renovascular hypertension caused by fibromuscular dysplasia (intimal fibroplasia) with congenital anomaly of the renal artery. Arteriography revealed complete occlusion from the root to the middle of the right renal artery and a collateral artery from the right lumbar artery. Histological examination showed intimal fibroplasia and three arterioles in the intima of the renal artery.

Adult↗
PubMedDate not supplied

A morphometric study of myelinated fibers in lumbar ventral roots and hypoglossal nerves in motor neuron diseases.

Morphometric studies of the 5th lumbar ventral spinal roots and hypoglossal nerves were made in twenty-one patients with motor neuron diseases and 12 age-matched controls. To evaluate the correlation between the numbers of the myelinated fibers and the patterns of white matter degeneration in spinal cords, the latter were classified into three groups: group A with selectively demarcated degeneration of lateral and anterior corticospinal tracts, group B with diffuse degeneration of antero-lateral spinal columns and group C with no degeneration of the spinal white matter. Although the numbers of large myelinated fibers of the 5th lumbar ventral roots were decreased in all three groups, the numbers in group C were significantly better preserved than those in group A. Even in the hypoglossal nerve, the numbers of total and large myelinated fibers were decreased and in addition, the longer the duration of bulbar signs and the more severe the pathological changes found in the hypoglossal nuclei, the fewer the number of myelinated fibers. Especially group A showed a significantly more severe decrease in the numbers of total and large myelinated fibers of the 5th lumbar ventral roots and hypoglossal nerves than group C. These findings suggest that the degeneration of the upper motor neuron accelerates that of the lower motor neuron system in motor neuron diseases.

Adult↗
PubMedDate not supplied

Late pathological changes of Carpentier-Edwards porcine bioprostheses in the mitral position.

Eighty-nine patients received mitral valve replacement with Carpentier-Edwards porcine bioprostheses between 1975 and 1983. Eighty-three patients (93.3%) were followed up after the operation; early death (within one month of operation) occurred in 6 patients and late death in 2 patients. After the operation, 64 survivors (85.3%), who did not require reoperation, exhibited improved symptoms according to the NYHA functional class. Of the 6 patients (6.7%) who required reoperation, 5 patients underwent reoperation 50 to 85 months after the implantation. Pathologically, all the removed valves showed degeneration of collagen and elastic fibers, no host endothelialization and mild to moderate infiltration of inflammatory cells. Thrombus in the left atrium was detected in one case. Destruction of the cusps was seen in three cases and calcification of the cusps developed in three cases. In general, the Carpentier-Edwards porcine bioprosthesis provided good clinical improvement over the periods studied. However, morphological changes of the bioprosthetic valve, such as destruction collagen and elastic fiber, and inflammatory cell infiltration of the cusps, seems to occur more frequently with the passage of time. We therefore suggest that patients with this prosthesis should be followed carefully, particularly at late intervals after implantation.

Adult↗
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Distal and proximal dissection of an abdominal aortic aneurysm.

A case of abdominal aortic aneurysm in which dissection developed in retrograde fashion into the thoracic aorta is reported. The aortogram showed findings similar to DeBakey Type-IIIb dissection. No intimal tear was seen in the thoracic aorta; however, the origin of the intimal tear was found in the abdominal aorta. Renal hypertension also developed due to distal dissection of the right renal artery. Closure of the primary intimal tear, partial closure of the false channel and removal of the right kidney were performed therefore, reattachment of vessels was not required. This was the first case in which a primary tear was seen in the abdominal aorta in our 37 surgical cases of dissecting aortic aneurysm. Three cases of retrograde dissection of abdominal aortic aneurysm have been reported in the English literature as far as we have determined. The importance of accurate detection of the origin of the intimal tear is emphasized.

Aortic Dissection↗
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Questionable role of glucose-insulin in cardioplegic solution.

To evaluate the myocardial protective effect of glucose-insulin (GI) in a cold cardioplegic solution, we compared the effect of a solution not containing GI (solution I) with that of an identical solution containing GI (solution II) under cardiopulmonary bypass in mongrel dogs. After 120 minutes of ischemic arrest, defibrillation was necessary to restore cardiac activity in 12.5% of the solution I group and 42.8% of the solution II group, respectively. No distinct intergroup differences were noted in recovery of left ventricular function, oxygen and lactate extraction of the myocardium during the post-arrest period, the myocardial ultrastructure, and myocardial ATP levels. Although creatine phosphate was less well preserved, glucose-6-phosphate and lactate were more accumulated in the solution II group than in the solution I group. Thus, significant advantages of substrate enhancement by addition of GI to cold cardioplegic solution were not found in spite of multidose cardioplegia and presence of noncoronary collateral blood flow.

Adenosine Triphosphate↗
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Differences in metabolic and morphological reactions after radiation therapy: proton NMR spectroscopy and imaging of patients with intracranial tumors.

PURPOSE: The purpose of the present study was to detect tumor cell viability, the diagnosis of which is the most important point in clinical therapy for malignant tumors. The advent of localized proton spectroscopy has made this detection possible. The spectral peak intensities were found to be very different depending on tumor tissue pathology. METHODS: The tumor cell reaction after radiation therapy was examined with proton localized spectroscopy in addition to enhanced MR imaging using a 1.5 Tesla MR system (Philips, Gyroscan S15-HP). Plain MR images (short spin echo) were used for localization pilot images, and after the MRS study, contrast enhanced MRI was carried out. Studies were performed pre-radiation, mid-radiation, and post-radiation if possible. MATERIALS: Sixteen patients (total 27 examinations) with intracranial tumors and three normal volunteers underwent proton NMR localized spectroscopy. The brain tumors were diagnosed before the MR study, and nine patients had metastatic brain tumors, such as adenocarcinoma, squamous cell carcinoma, and small cell carcinoma, and seven other patients were diagnosed with glioma-type tumors. RESULTS: The reaction patterns of proton NMR spectroscopy of brain tumors after radiation therapy were very different and depended on tumor histology. CONCLUSION: Proton NMR spectroscopy is an excellent means of determining tumor cell viability.

Adult↗
PubMedDate not supplied

Unusual pulmonary metastasis of neuroblastoma: a case report.

A case of unusual pulmonary metastasis of neuroblastoma in an 8-year-old girl is presented. Nodular opacities mimicking pulmonary tuberculosis first appeared in lung apices on chest radiographs. They subsequently developed into extensive consolidations with mediastinal involvement. Metastasis of neuroblastoma was confirmed at autopsy.

Child↗