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Biomedical subjects

K Tomoda

Publications and source records attributed to K Tomoda.

179 records · Page 10Linked to original sources
PubMedDate not supplied

Sensitivity of double-phase helical CT during arterial portography for detection of hypervascular hepatocellular carcinoma.

PURPOSE: The purpose of our work was to determine the usefulness of double-phase helical CT during arterial portography (CTAP) for the detection of hypervascular hepatocellular carcinoma (HCC). METHOD: Eighty-four patients with 176 hypervascular HCC nodules underwent double-phase CTAP. Hypervascular HCCs were diagnosed by iodized oil CT after transcatheter arterial chemoembolization (TACE). The first-phase images were obtained 30 s after the initiation of injection of a nonionic iodinated contrast medium into the superior mesenteric artery or splenic artery, and the second-phase images were obtained after 70 s. These images were interpreted separately for detection of HCC. RESULTS: The double-phase CTAP detected two nodules and six nodules that were missed by the first- and second-phase images, respectively. The sensitivity for hypervascular HCC nodules was 89% for the first phase, 91% for the second phase, and 93% for the first phase and second phase combined. The double-phase CTAP showed significantly superior sensitivity to the first-phase CTAP for detecting HCC nodules (p < 0.05). However, there was no statistically significant difference between the sensitivities of the double-phase CTAP and the second-phase CTAP. The positive predictive values of the double-phase images were inferior to those of either the first-phase or the second-phase images alone. CONCLUSION: Double-phase helical CTAP was found to be no better than second-phase CTAP alone for the detection of hypervascular HCC nodules.

Adult↗
PubMedDate not supplied

Characterization of the calcium influx induced by depolarization of guinea pig cochlear spiral ganglion cells.

We examined dynamic changes in intracellular calcium ion concentrations ([Ca2+]i) in isolated cochlear spiral ganglion cells (SGCs) of the guinea pig using digital imaging microscopy and the Ca(2+)-sensitive fluorescence dye fura-2. [Ca2+]i in SGCs was 83 +/- 22 nM (n = 50, means +/- SD) in cell somata at the resting state. Reversible increases in [Ca2+]i were elicited during membrane depolarization by high K+ (150 mM). This increase in [Ca2+]i was not observed under conditions of depolarization in Ca(2+)-free medium containing 1 mM EGTA. In addition, these increases in [Ca2+]i were sensitive to L-type calcium channel ligands, viz., antagonized by nifedipine (50 microM), verapamil (10 microM) and enhanced by BAY K 8644 (1 microM). These observations suggest that increases in [Ca2+]i of cochlear SGCs induced by high K+ are due to an influx of extracellular Ca2+, probably through voltage-gated L-type calcium channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMedDate not supplied

Type II collagen-induced autoimmune otospongiosis. A preliminary report.

Otospongiosis-like lesions were induced in rats by immunizing them with native type II collagen. Immunized rats had antibody responses specific for native type II collagen and developed otospongiosis-like lesions. The spongiotic lesion was characterized by numerous osteocytes and osteoblasts in the vascular spaces and by dark staining probably due to the chemical alteration of ground substances. Bone resorption and new bone formation were clearly visible. Immunofluorescence studies demonstrated deposition of immunoglobulin and complement on the bone matrix and wall within the area of spongiosis. An antibody-mediated etiopathogenesis was suspected.

Animals↗
PubMedDate not supplied

Type II collagen-induced autoimmune sensorineural hearing loss and vestibular dysfunction in rats.

Autoimmune sensorineural hearing loss was induced in rats by immunizing them with native bovine type II collagen. Type I and denatured type II collagen, administered by an identical immunization procedure, would not induce disease. Evidence of sensorineural hearing loss was obtained by measuring the brainstem evoked potential and by observing histopathologic changes consisting of cochlear nerve degeneration and perineural vasculitis in affected animals. Immunized animals had high levels of antibodies to native type II collagen.

Animals↗
PubMedDate not supplied

Histology of human eustachian tube muscles: effect of aging.

Forty-eight specimens of human eustachian tube tensor and levator muscles were examined histologically in order to study their functions and the effect of aging. The muscle fibers reach their maximum growth in the third decade with a narrow short diameter: tensor 21.8 micron and levator 24.5 micron; with advancing age, they were prone to atrophy, particularly in the tensor. Three muscle fiber types, red, white, and intermediate, were identified in the tubal muscles. The white fibers predominated in the tensor, and they were a main component of muscle fibers in fetuses and elderly adults. Lipofuscins were located in the periphery of muscle fibers, dominantly in the levator, and became numerous and larger with age. Our observations suggest that 1) the tensor produces a rapid opening of the eustachian tube while the levator creates tension and dilates the pharyngeal orifice of the tube for a relatively long period, and 2) these muscle functions deteriorate with advancing age.

Adolescent↗
PubMedDate not supplied

Antibody activity in perilymph from rats with type II collagen-induced autoimmune inner ear disease.

Rats were immunized with native type II bovine collagen to induce autoimmune inner ear disease, and the antibody activity in the inner ear fluid was measured. Antibody activity against type II collagen was detected in the perilymph at about 10% to 20% of serum level. Thus, the presence of antibody against type II collagen in inner ear fluid may imply an immune injury mechanism in inner ear diseases.

Animals↗
PubMedDate not supplied

Type II collagen-induced autoimmune inner ear lesions in guinea pigs.

Guinea pigs immunized with type II collagen developed histologic changes resembling those observed in patients with sensorineural hearing loss associated with connective tissue diseases. The histologic changes observed in the inner ears of these guinea pigs included spiral ganglion cell degeneration, atrophied organ of Corti, atrophy of stria vascularis, and mild extension of Reissner's membrane. These pathologic changes were accompanied by both humoral and cell-mediated immune responses directed against type II collagen--a collagen found in the subepithelial layer of the endolymphatic duct and spiral ligament. These findings suggest that an immune response directed against type II collagen can induce inner ear lesions.

Animals↗
PubMedDate not supplied

Type II collagen-induced autoimmune salpingitis in rats.

Autoimmune salpingitis was induced in 17 (85%) of 20 outbred Wistar rats by immunization with bovine type II collagen; three of those also developed eustachian tube chondritis. The lesions were characterized by infiltrations of a large number of mononuclear cells in the mucosa and submucosa, destruction of cartilaginous structure, and deposition of IgG and complement C3. The animals had high titers of anti-type II collagen antibody. Immunohistochemical examination using monoclonal antibody to type II collagen revealed the presence of type II collagen in the eustachian tube cartilage. These observations suggest a causal relationship between autoimmunity to type II collagen and salpingitis in the rat, and this animal model may be useful in defining the pathogenesis of eustachian tube diseases mediated by immunity to type II collagen.

Animals↗
PubMedDate not supplied

Deviation with increasing age in histologic appearance of submucosal glands in human eustachian tubes.

74 tubal specimens from the temporal bones of 37 autopsy cases of various ages (8 fetuses, 12 children, 4 young adults, 36 middle-aged adults, and l4 elderly adults) were examined histologically to study the deviation with increasing age in the submucosal glands of Eustachian tube. The tubal glands consisted of acini (terminal secretory portions) and three duct systems (intercalated, striated and excretory ducts). Cytologically, they were of the mixed type with crescents. It was observed that the mucous acinar cells were predominant in children, as compared with the serous acinar cells. These latter increased prominently in middle age, accompanied by a decrease in the number of mucous cells. Among the elderly, both types of acinar cells decreased and tended to be atrophic. On the other hand, oncocytic changes of the ductal epithelia were discovered in the pharyngeal part of Eustachian tubes of subjects over 60 years old. These aging changes may play an important role in the pathophysiology of patency and excretory processes of the Eustachian tube.

Adolescent↗
PubMedDate not supplied

Helical CT imaging of gastric cancer: normal wall appearance and the potential for staging.

PURPOSE: To evaluate the CT appearance of the normal gastric wall and the effectiveness of contrast enhanced helical CT for T-staging of gastric cancer. METHODS: For the basic experiment, two resected stomachs with gastric cancer were filled with water and examined by helical CT imaging. For the clinical study, 59 consecutive patients with gastric cancer who had received preoperative helical CT examination and had also been operated on were entered in this study. Helical CT images were evaluated independently by three radiologists without knowledge of histological staging results. RESULTS: The basic examination of a histopathological correlation with CT images revealed that the inner layer with high attenuation corresponded to the mucosa and the muscular layer of the mucosa, the middle layer with low attenuation to the submucosal layer consisting of coarse tissues and containing fatty tissues, and the outer layer with slightly high attenuation to the proper muscle with serosa. The clinical study revealed that the rate of correct diagnosis through consensus reading was 66.1%. CONCLUSION: The entire stomach with a well-stained mucosa can be visualized by contrast enhanced helical CT. However, T-staging of gastric cancer by helical CT did not appear to improve the accuracy of staging.

Adipose Tissue↗
PubMedDate not supplied

MRI of symptomatic sacral perineural cyst.

Sacral perineural cyst is a relatively rare condition. To our knowledge, reports of MR findings associated with sacral perineural cyst have been limited to only six cases. We present for the first time high field MR findings in a case of sacral perineural cyst. The cyst appeared as a cystic lesion in the sacral spinal canal and had intermediate signal intensity on T1W images and high signal intensity on T2*W images compared with CSF. Slight erosion remodeling of the sacrum was also seen anteriorly. Our case was symptomatic and present with radiculopathy (sciatic pain). Surgical treatment was done to result in dramatic improvement of the sciatic pain.

Cysts↗
PubMedDate not supplied

Pancreatic angiography using balloon catheter occlusion and a vasoconstrictor.

When a vasoconstrictor (noradrenaline) was injected during occlusion of the common hepatic artery with a balloon catheter, the vasoconstrictor flowed only into the proper hepatic artery and constricted it. The balloon was immediately deflated and contrast medium injected into the common hepatic artery. The flow of the contrast medium into the gastroduodenal artery was then increased, clearly visualizing the entire pancreatic-duodenal arcade.

Angiography↗
PubMedDate not supplied

Computed tomography following endoscopic sclerotherapy of esophageal varices.

Computed tomography of the chest following endoscopic injection sclerotherapy for esophageal varices was performed in 17 procedures in 13 patients. CT scans were obtained before and within 48 hours after the procedure. CT findings included: esophageal wall thickening; a low-attenuating lesion within the wall of the esophagus with varying appearances, either laminated, localized, or inhomogeneous; a mediastinal lesion; pleural effusion; and various types of pulmonary changes such as atelectasis, pleural-based lesions, dilatation of peripheral pulmonary vessels, and nodular lesions. However, on follow-up CT they had regressed or disappeared. The changes in the mediastinum and pleural space might be caused by direct extension of inflammation from the esophagus, but those in the lungs, especially dilatation of peripheral vessels, may be caused by the sclerosing agent passing to the pulmonary vessels.

Adult↗
PubMedDate not supplied

Combined hepatocellular and cholangiocellular carcinoma.

A patient with combined hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) underwent partial hepatectomy, and the correlation between the pathological and radiological findings was examined retrospectively. The tumor showed hypoattenuation and hypoenhancement relative to the surrounding liver parenchyma on noncontrast and postcontrast CT, respectively. Both the HCC and CCC components of the tumor showed hypointensity and heterogeneous hyperintensity on T1- and T2-weighted spin echo images, respectively. While the HCC component of the tumor showed hyperenhancement relative to the liver parenchyma on arterial phase images of dynamic MR imaging, the CCC component showed hypoenhancement. When components with different degrees of vascularity are seen in a hepatic tumor, combined HCC and CCC should be considered.

Adult↗
PubMedDate not supplied

Cationic multilamellar liposome-mediated human interferon-beta gene transfer into cervical cancer cell.

Interferons (IFNs) have antineoplastic activity, but it has been reported that treatment with IFN alone is not effective in many cancers. To enhance the effect of growth inhibition on tumor cells by raising the concentration, we attempted the transfection of cervical cancer cells, HeLa cells, with human interferon-beta (HuIFN-beta) cDNA contained in the expression vector pRSV delivered by cationic multilamellar liposomes, which resulted in the secretion of HuIFN-beta into the medium. The concentration of HuIFN-beta in the medium was 22 IU/ml by 72 hours after transfection of 10 ng DNA, and provoked around 45-fold cell growth inhibitory effect compared with that of exogenously added HuIFN-beta (1000 IU/ml). This strong growth inhibition was considered to be due to the action of HuIFN-beta in a paracrine manner, and a notable fraction of the cell death was apoptotic.

Apoptosis↗
PubMedDate not supplied

MRI appearance of ruptured corpus luteum.

A 20-year-old woman was admitted complaining of lower abdominal pain. Transabdominal ultrasound revealed a fluid collection in the pouch of Douglas and an irregularly shaped ovary with cystic lesions. Malignant cystic mass of the right ovary was highly suspected from the ultrasound findings. Transvaginal peritoneal centesis yielded a bloody fluid, but the pregnancy test was negative. On the third day of admission, menstruation began. MR examination performed four days after the initial onset of pain showed a subacute hematoma just adjacent to the right ovary, and segmental interruption of the right ovarian cortex. Based on these MR findings and the patient's history, subacute hemorrhage from the right ovarian corpus luteum was suspected, and this was confirmed with surgical exploration.

Adult↗