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Biomedical subjects

S Akaki

Publications and source records attributed to S Akaki.

29 records · Page 2Linked to original sources
PubMed1991

[Quantitative evaluation of regional blood flow in pulmonary sarcoidosis with bull's eye analysis].

Lung perfusion scintigraphy was performed in 23 patients with pulmonary sarcoidosis and in 11 normal volunteers. Bull's eye analysis was used to analyze regional pulmonary blood flow quantitatively. First, whole lung perfusion images were divided into three regions by three concentric circles. Then radial axes were projected from the center to define 36 x 10 degrees sectors. The counts for each sector were calculated and a Bull's eye image was displayed. The counts were compared with the lower limit of normal (mean - 2SD), and as the indices of reduction in perfusion, extent score (ES) and severity score (SS) were calculated. ES and SS showed significant reduction in perfusion 16 patients (70%) with sarcoidosis. In stage II sarcoidosis, both ES and SS were significantly higher than in stage I sarcoidosis (p less than 0.05). In comparison with the findings of transbronchial lung biopsy, both ES and SS had correlations with the degree of alveolitis and ES had a correlation with the degree of angiitis. Both ES and SS have no correlation with 67Ga scintigraphy findings. In comparison with clinical data, ES had a positive correlation with serum angiotensin-converting enzyme activity (p less than 0.05), and SS had a significant positive correlation with bronchoalveolar lavage fluid.CD+/CD8+ ratio (p less than 0.05). The Bull's eye analysis was considered useful for the quantitative evaluation of regional pulmonary blood flow in pulmonary sarcoidosis, and it was suggested that the mechanism of reduction in perfusion might be resulted mainly in its alveolitis and angiitis. Ventilation abnormality, which may happen prior to reduction in perfusion, may be an important factor of reduction in perfusion.

Adult↗
PubMed1990

[A new application of bull's-eye analysis to lung perfusion scintigraphy].

Technetium-99m macroaggregated albumin lung perfusion scintigraphy was performed and evaluated semiquantitatively by bull's-eye analysis in 24, including 7 with central pulmonary carcinoma, 3 with hypersensitivity pneumonitis (HP), 3 with diffuse panbronchiolitis (DPB) and 11 normal subjects. First, whole lung field was divided into three regions by three concentric circles. And then radial axes were projected from the center to define 36 sectors, 10 degree each. The counts of each sector was calculated and bull's-eye image and circumferential profile curve were displayed. The patient's map was compared with the lower limit of normal (mean-2 SD), and the extent score (ES) and the severity score (SS) were calculated. The ES was 0.25 +/- 0.12 in pulmonary carcinoma (n = 7), 0.08 +/- 0.07 in HP (n = 3), 0.06 +/- 0.04 in DPB (n = 3). The SS was 26.39 +/- 15.17 in pulmonary carcinoma, 4.75 +/- 5.57 in HP, 4.29 +/- 3.67 in DPB. In one case of central pulmonary carcinoma, segmental perfusion defect was evaluated semiquantitatively by bull's-eye image and circumferential profile curve. And in one case of HP, the change of regional pulmonary blood flow could be followed easily using extent and severity map. This new application of Bull's eye analysis to lung perfusion scintigraphy might be useful to evaluate regional pulmonary blood flow.

Alveolitis, Extrinsic Allergic↗
PubMedDate not supplied

Asymptomatic membranous obstruction of the inferior vena cava due to large intrahepatic collaterals.

This paper presents a case of asymptomatic membranous obstruction of the inferior vena cava with a rare hemodynamic pattern consisting of large intrahepatic venous connections between the right inframembranous and the middle supramembranous hepatic vein. These remarkably large collaterals obviated significant enlargement of the azygous venous system and the development of a Budd-Chiari syndrome.

Aged↗
PubMedDate not supplied

Bile duct stenosis due to portal cavernomas: MR portography and MR cholangiopancreatography demonstration.

We report two cases of bile duct stenosis due to portal cavernomas. Smooth stenoses were seen arising from both walls of the common bile duct on magnetic resonance (MR) cholangiopancreatography. On contrast-enhanced MR portography, peribiliary tortuous vessels were evident, indicating portal cavernomas. MR imaging can evaluate the biliary tree and portal systems noninvasively and was useful for evaluating this condition.

Aged↗
PubMedDate not supplied

The effect of various chemotherapeutic agents given with mild hyperthermia on different types of tumours.

It has been shown that hyperthermia can enhance the cytotoxicity of some chemotherapeutics. However, the most effective agent(s) at elevated temperatures have yet to be determined. A previous study suggests that the drug of choice at elevated temperatures may be different from that at the physiological temperature, and that the alkylating agents may be most effective at elevated temperatures. To further investigate these possibilities, the effect of chemotherapeutic agents were compared. These agents were cyclophosphamide, ifosfamide, melphalan, cis-diamminedichloroplatinum (II), 5-fluorouracil, mitomycin C and bleomycin. Three tumours (mammary carcinoma, osteosarcoma and squamous cell carcinoma) were used. They were transplanted into the feet of C3H/He mice. When tumours reached 65 mm(3), a test agent was injected intraperitoneally. Tumours were immediately heated at 41.5 degrees C for 30 min, and the tumour growth (TG) time was studied for each tumour. Using the TG times, the TG-50 (the time required for one-half of the total number of the treated tumours to reach the volume of 800 mm(3) from 65 mm(3)) was calculated. Subsequently, the tumour growth delay time (GDT) and the thermal enhancement ratio (TER) were obtained. The GDT was the difference between the TG-50 of treated tumours and that of non-treated control tumours. The TER was the ratio of the GDT of a group treated with an agent at 41.5 degrees C to that of a group treated with the agent at room temperature. Results showed that the top three effective agents tested at 41.5 degrees C were solely alkylating agents--CY, IFO and L-PAM--for each kind of tumour. A GDT of cisplatin was smaller than those of the alkylating agents. The smallest TER, 1.1, was observed for 5-fluorouracil, which was given for mammary carcinoma, and for mitomycin C, which was given for squamous cell carcinoma. It could be concluded that the alkylating agents at elevated temperatures might be the drugs of choice for many types of tumours. The possible mechanisms of thermal enhancement associated with these agents are discussed.

Animals↗
PubMedDate not supplied

Evaluation of crossing vessels in patients with ureteropelvic junction obstruction by means of helical CT.

Helical computed tomography (CT) was used to demonstrate the distribution of crossing vessels in patients with ureteropelvic junction (UPJ) obstruction for planning surgical management. Twenty patients with symptomatic UPJ obstruction were evaluated with dual-phase contrast material-enhanced helical CT. In addition to axial images, coronal, sagittal, and curved paracoronal images along the crossing vessels or the UPJ were obtained by means of multiplanar reconstruction. Crossing vessels were evaluated according to type, position, and association with UPJ obstruction. Fifteen vessels in 12 of the 20 patients were found to cross the UPJ at helical CT. Nine vessels were arteries and six were veins; seven vessels crossed anteriorly and eight crossed posteriorly. In 11 patients, crossing vessels were thought to be associated with UPJ obstruction at helical CT; retroperitoneoscopic repair was performed, and the diagnosis was found to have been accurate in all except one. In the eight patients in whom no significant vessels were seen and the one patient in whom the crossing vessel was not associated with UPJ obstruction at helical CT, endopyelotomy was performed and UPJ obstruction was relieved, with no complications. Helical CT is useful for evaluation of vessels crossing the UPJ and for planning surgical management.

Adolescent↗
PubMedDate not supplied

Attenuation changes in periportal region during triple-phasic contrast-enhanced CT.

OBJECTIVE: To evaluate attenuation changes in the periportal regions of the liver during triphasic contrast CT. MATERIALS AND METHODS: The study group consisted of 93 patients, all of whom underwent triphasic contrast-enhanced CT with a helical scanner for survey of liver disease. The three phases included the arterial phase, portal venous phase, and equilibrium phase. Attenuation changes in the periportal area in each phase were evaluated in every patient. Factors surmised to be related with periportal low attenuation, including elevation of venous pressure, presence of ascites, cardiac enlargement, and lymphadenopathy of the porta hepatis and lesser omental region, were also evaluated. RESULTS: Periportal low attenuation was seen in 65 patients (69.8%) in the portal venous phase where the liver parenchyma showed the largest attenuation value. Among them, periportal low attenuation was continuously observed in every phase in 13 patients (13.9%), while it was confirmed only in the portal venous phase in 28 patients (30.1%), and in 24 patients (32.2%) in the portal venous phase plus either the arterial or equilibrium phase. None of the factors that were investigated could be related to the appearance of periportal low attenuation. CONCLUSION: Periportal low attenuation was a relatively common finding in the portal venous phase of triphasic contrast CT, whereas it was less usual in the arterial or equilibrium phase.

Adult↗
PubMedDate not supplied

Endometrial carcinoma: multisection dynamic MR imaging using a three-dimensional FLASH technique during breath holding.

PURPOSE: Our aim was to investigate the usefulness of multisection dynamic MR imaging using a 3D FLASH technique during breath holding in assessing myometrial invasion by endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight endometrial carcinomas were evaluated with pathologic correlation. Dynamic MR imaging was performed using the 3D FLASH technique during breath holding. We compared accuracy in the assessment of myometrial invasion by endometrial carcinoma between T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images. RESULTS: The accuracy rates in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images were 64.3%, 67.8%, and 85.7%, respectively. Statistically significant differences were seen between dynamic MR images and both T2-weighted images and contrast-enhanced T1-weighted images. CONCLUSION: Multisection dynamic MR imaging using the 3D FLASH technique during breath holding is useful for the evaluation of myometrial invasion by endometrial carcinoma with polypoid growth or an unclear junctional zone on T2-weighted images.

Contrast Media↗
PubMedDate not supplied

Overexpression of manganese superoxide dismutase gene suppresses spontaneous apoptosis without a resultant alteration in in vivo growth of the mouse fibrosarcoma, FSa-II.

The relationship between spontaneous apoptosis and overexpression of manganese superoxide dismutase (MnSOD) gene was examined in vivo. The mouse fibrosarcoma cells expressing high MnSOD activities due to transfection with the human MnSOD cDNA (SOD-H), or the fibrosarcoma cells transfected with the selectable marker alone (NEO), were transplanted into immune-deficient Fox Chase SCID C.B-17/Icr-scid Jcl mice. Apoptosis in tumors was visually quantified by the in situ end-labeling method. The number of apoptotic cells in the SOD-H tumors was significantly less than that in the NEO tumors. The tumor growth time of the SOD-H tumors to grow from 34 to 500 mm3 in one-half of the mice was slightly longer than that of the NEO tumors, but the difference was not statistically significant. These results suggest that overexpression of MnSOD gene is involved in the suppression of spontaneous apoptosis, without a resultant alteration in the tumor growth.

Animals↗
PubMedDate not supplied

MR appearance of endometrial carcinoma and mucinous cystadenoma in a postmenopausal patient treated with tamoxifen for breast cancer.

We present a case of endometrial carcinoma accompanied with mucinous cystadenoma in a 70-year-old postmenopausal woman treated with tamoxifen for breast cancer demonstrated by MR imaging. Tamoxifen therapy (20 mg/day) had been carried out for more than 11 years since the surgical procedure for the primary tumor. MR images showed a markedly enlarged uterus containing endometrial carcinoma, cystic atrophy of the endometrium, and a right adnexal mass with multicystic components of various signal intensities.

Aged↗