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Biomedical subjects

I Joja

Publications and source records attributed to I Joja.

At least 37 records · Page 2Linked to original sources
PubMed1987

Studies of left ventricular volume estimation from gated blood pool scan with the use of regression equations.

The authors carried out experimental and clinical studies of left ventricular volume measurement using equilibrium-gated blood pool scan. Using phantoms, we experimentally obtained a regression equation between radioisotope levels and camera counts. From this equation, we deduced a regression equation between camera counts and volumes, which was then used for calculation of left ventricular volumes using count technique. In an experiment using phantom with various volumes, we obtained a favorable result that the average absolute error between the true and measured volumes was as small as 6.8%. In 11 patients, we calculated the left ventricular volume and ejection fraction employing the regression equation and compared the calculated values with the values obtained by cinemascopy. This comparison disclosed an excellent correlation (r = 0.955 for end-diastolic volume, 0.997 for end-systolic volume and 0.853 for ejection fraction). Mean absolute error was 16.2% for end-diastolic volume and 16.0% for end-systolic volume. These results indicate that this technique is clinically applicable.

Adolescent↗
PubMed1985

Radiation-induced peroxidation of lipid dissolved in organic solvent and its inhibition by alpha-tocopherol and cepharanthine.

Effects of cepharanthine and alpha-tocopherol on radiation-induced peroxidation of lipids dissolved in methanol(MeOH)-chloroform (CHCl3)-H2O(v/v, 2/1/0.8) were examined. alpha-Tocopherol strongly inhibited radiation-induced peroxidation of lipids dissolved in MeOH-CHCl3-H2O. However, cepharanthine exhibited a weak inhibitory action in this system. The change in the absorption spectrum of alpha-tocopherol and cepharanthine by X-irradiation was measured. The reagents were dissolved in 95% EtOH acidified with 20 mM HCl and in MeOH-CHCl3-H2O. alpha-Tocopherol exhibited the change in its absorption spectrum in both systems, and seemed to be oxidized at a high rate by free radicals. However, cepharanthine slightly exhibited the change in its spectrum in MeOH-CHCl3-H2O, but not in acidified EtOH.

Alkaloids↗
PubMed1984

[Thallium-201 chloride dynamic analysis using thallium-201 chloride and sodium iodide-131 thyroid subtraction scintigraphy].

The mechanism of 201Tl chloride accumulation is unclear in thyroid gland and thyroid tumor. This report examines 108 patients that received thyroid scintigraphy examinations with both 201Tl chloride and sodium 131I. The patients were diagnosed clinically and histologically whenever possible. The ROI were obtained by subtraction imaging with both isotopes and by subtraction positive and negative areas of imaging. Dynamic curves were obtained for 201Tl chloride per square unit of each ROI. The dynamic curve in the radioiodide-accumulated area was examined. The data indicate that the clearance rate of 201Tl chloride (T15) was correlated with the sodium 131I uptake rate at 24 h (r = 0.70).

Adolescent↗
PubMed1982

Inhibition of nitroblue tetrazolium reduction by metallothionein.

Metallothionein inhibited in a concentration-dependent fashion the reduction of nitroblue tetrazolium [NBT] mediated by xanthine oxidase and by NADH-phenazine methosulfate. This catalytic activity of metallothionein for dismutation of O2- is dependent on the copper content in metallothionein.

Animals↗
PubMedDate not supplied

Struma ovarii: appearance on MR images.

BACKGROUND: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images. METHODS: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison of MR images with resected specimens. RESULTS: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high, with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous materials. CONCLUSIONS: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii.

Adult↗
PubMedDate not supplied

Cervical carcinoma: efficacy of thin-section oblique axial T2-weighted images for evaluating parametrial invasion.

BACKGROUND: To investigate the efficacy of thin-section oblique axial T2-weighted images in the assessment of parametrial invasion by cervical carcinoma. METHODS: One hundred parametria of 50 patients with cervical carcinoma were evaluated with pathologic correlation. We compared the sensitivity, specificity, and diagnostic accuracy in the assessment of parametrial invasion by cervical carcinoma between axial T2-weighted images and thin-section oblique axial T2-weighted images. RESULTS: Thin-section oblique axial T2-weighted images provided accurate cross sections of the cervix with excellent detail and detected parametrial invasion more accurately than did axial T2-weighted images showing cross sections of the trunk. Although the sensitivity, specificity, and accuracy for parametrial invasion were 46.4%, 91.7%, and 79.0%, respectively, on axial T2-weighted images, the corresponding values were 67.9%, 97. 2%, and 89.0%, respectively, on thin-section oblique axial T2-weighted images. There were statistically significant differences in the sensitivity (p = 0.014), specificity (p = 0.046), and accuracy (p = 0.002) in detecting parametrial invasion between these two types of images. CONCLUSIONS: Thin-section oblique axial T2-weighted images are useful for the assessment of parametrial invasion by cervical carcinoma.

Adenocarcinoma↗
PubMedDate not supplied

Endometrial carcinoma: efficacy of thin-section oblique axial MR images for evaluating cervical invasion.

BACKGROUND: To investigate the efficacy of thin-section oblique axial magnetic resonance (MR) images in evaluating cervical invasion by endometrial carcinoma. METHODS: Sixty-seven patients with endometrial carcinoma were evaluated with pathologic correlation. We compared the accuracy in the assessment of cervical invasion by endometrial carcinoma between parasagittal MR images and thin-section oblique axial MR images by using T2-weighted and contrast-enhanced T1-weighted pulse sequences. RESULTS: Cervical invasion by endometrial carcinoma was confirmed by pathologic examination. Cervical invasion was seen in 16 patients. The accuracy rates of parasagittal T2-weighted images, thin-section oblique axial T2-weighted images, parasagittal contrast-enhanced T1-weighted images, and thin-section oblique axial contrast-enhanced T1-weighted images were 74.7%, 89.5%, 82.0%, and 95.5%, respectively. Statistically significant differences were seen between parasagittal T2-weighted images and thin-section oblique axial T2-weighted images (p = 0.002) and between parasagittal contrast-enhanced T1-weighted images and thin-section oblique axial contrast-enhanced T1-weighted images (p = 0.003). CONCLUSION: Thin-section oblique axial MR images are considered to be useful for the assessment of cervical invasion by endometrial carcinoma.

Adenocarcinoma↗
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

Uterine cirsoid aneurysm: MRI and MRA.

Uterine cirsoid aneurysm is uncommon. It is important to make a diagnosis of this disease preoperatively, because repeated curettages may induce life-threatening massive genital bleeding. We present a case of a 51-year-old woman with uterine cirsoid aneurysm in whom MRI and MRA were very useful for the preoperative diagnosis. The radiologic appearances on ultrasonography, CT, conventional SE MRI, MRA, dynamic MRI, and pelvic angiography are presented. Conventional SE T1-weighted and T2-weighted images demonstrated multiple flow voids in the uterus and bilateral adnexal regions. MRA demonstrated a cluster of distinct, tortuous, and coiled vascular channels in the pelvis. MRA could obtain images almost equal to angiography and was considered to be an excellent noninvasive imaging technique for the diagnosis of uterine cirsoid aneurysm.

Aneurysm↗
PubMedDate not supplied

Endometrial carcinoma: dynamic MRI with turbo-FLASH technique.

PURPOSE: Our goal was to investigate the usefulness of dynamic MRI with the turbo-FLASH technique in estimating myometrial invasion by endometrial carcinoma. METHOD: Forty-six patients with endometrial carcinomas were evaluated with pathologic correlation. Dynamic MRI was performed with the rapid administration of Gd-DTPA using the turbo-FLASH technique. RESULTS: The inner muscle layer showed more rapid contrast enhancement effects than the outer muscle layer even after menopause. Contrast-to-noise ratio between the inner muscle layer and endometrial carcinoma was maximum at approximately 50 s after administration of Gd-DTPA. In postmenopausal women, the accuracy in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MRI was 66.7, 77.8, and 92.6%, respectively. CONCLUSION: Dynamic MRI with the turbo-FLASH technique is considered to be a useful imaging method for the estimation of myometrial invasion by endometrial carcinoma, especially in postmenopausal patients.

Adult↗
PubMedDate not supplied

Sclerosing stromal tumor of the ovary: US, MR, and dynamic MR findings.

The US, MR, and dynamic MR findings in four patients with sclerosing stromal tumor of the ovary are reported. US showed a tumor with multilocular cystic components and irregularly thickened septa and tumor walls or a solid tumor including several small cystic components. On T2-weighted MR images, signal intensities of the cystic components were high and those of the solid components were inhomogeneous, ranging from intermediate-high to high. Dynamic MRI demonstrated marked early enhancement of the solid components.

Adolescent↗
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

Fetal hydrocephalus secondary to intraventricular hemorrhage diagnosed by ultrasonography and in utero fast magnetic resonance imaging. A case report.

Although fetal hydrocephalus is commonly detected by prenatal ultrasonographic examination, posthemorrhagic hydrocephalus has rarely been observed in the fetus. We report a case of hydrocephalus secondary to intraventricular hemorrhage (IVH) diagnosed by in utero magnetic resonance imaging (MRI) at 37 + 1 weeks of gestation. Ultrasonography revealed enlargement of the bilateral ventricles and an irregular mass measuring 20 x 12 x 10 mm in the right lateral ventricle. T1-weighted images with two-dimensional fast low-angle shot (2D-FLASH) and T2-weighted images with half-Fourier single-shot turbo spin echo (HASTE) demonstrated that an old hemorrhagic clot existed in the right lateral ventricle of the fetus. Hydrocephalus secondary to IVH was confirmed by postnatal MRI and ventriculoscopy. Fast MRI is especially useful for prenatal diagnosis of fetal brain abnormalities because it minimizes the artifact of fetal movement.

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↗