Comparative studies on fine-needle aspiration cytology with ultrasound scanning in the assessment of thyroid nodule

The clinical usefulness of ultrasound scanning in the assessment of thyroid nodule was examined. The total diagnostic accuracy for aspiration biopsy cytology (ABC) in the differentiation of benign from malignant thyroid nodules was 92.4% in 26 patients, which is similar to that of previous reports when compared with the findings of pathological examination by surgery. Additionally, the diagnostic efficacy of high resolution ultrasonography was evaluated based on the results of ABC. When the echogram of 90 patients with a thyroid nodule was divided into eight patterns according to Obara's classification, only 64.3% of the carcinoma exhibited the typical malignant pattern of ultrasonography and 21.4% of the carcinoma exhibited the ultrasonographically homogenous nodule with a clear margin, which was often observed in the benign nodules. Therefore, it is necessary to be very careful when differentiating malignant from benign thyroid nodules by ultrasonography. In conclusion, although high resolution ultrasonography provides useful information for the assessment of most thyroid nodules, all ultrasonography (including high resolution ultrasonography) should be combined with ABC for the final diagnosis.

Transformation of arachidonic acid by 5- and 15-lipoxygenase pathways in bovine adrenal fasciculata cells

[1-14C]Arachidonic acid was incubated with isolated bovine adrenal fasciculata cells for 15 min at 37gC. The metabolites were separated and purified by reverse- and straight-phase high performance liquid chromatography, and identified by gas chromatography-mass spectrometry or radioimmunoassay. Identified metabolites were 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE), leukotriene B4 and 11,14,15-trihydroxy-5,8,12-eicosatrienoic acid (11,14,15-THET). Addition of 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE), an intermediate metabolite of 15-lipoxygenase pathway to microsomes of bovine adrenal fasciculata cells resulted in the formation of 11,14,15-THET. The formation of 11,14,15-THET by microsomes was not dependent on the presence of NADPH, while it was dose-dependently suppressed by ketoconazole, a potent inhibitor of cytochrome P-450 dependent enzymes. These results indicate that 5- and 15-lipoxygenase pathways of arachidonic acid may exist in bovine adrenal fasciculata cells and that 15-HPETE is further metabolized to 11,14,15-THET by adrenal microsomal cytochrome P-450.

Possible site of action of 5-hydroperoxyeicosatetraenoic acid derived from arachidonic acid in ACTH-stimulated steroidogenesis in rat adrenal glands

The site of action of 5-hydroperoxyeicosatetraenoic acid (5-HPETE) in ACTH-induced stimulation of steroidogenesis was examined in rat adrenocortical fasciculata cells. Prior addition of AA861, a specific inhibitor of 5-lipoxygenase, had no significant effect on cyclic AMP-dependent protein kinase activity and cholesterol esterase activities, when stimulated by ACTH in adrenocortical cells, compared with that stimulated by ACTH alone. Cholesterol accumulation in the mitochondria of cells treated with ACTH and cycloheximide was also not altered by pretreatment with AA861. We found, however, that pregnenolone formation, stimulated by ACTH, decreased in a dose-dependent manner when cells were pretreated with AA861. The inhibition of ACTH-stimulated pregnenolone formation by treatment with AA861 was restored only by prior addition of 5-HPETE. Furthermore, addition of AA861 also did not affect the conversion of pregnenolone into corticosterone. In conclusion, 5-HPETE may act at the level of the mitochondria in ACTH-induced steroidogenesis in rat adrenal fasciculata cells.

Arachidonic acid metabolites by cytochrome P-450 dependent monooxygenase pathway in bovine adrenal fasciculata cells

[1-14C]Arachidonic acid was incubated with microsomes of bovine adrenal fasciculata cells in the presence of 1 mM NADPH for 30 min at 37 degrees C. The metabolites were separated and purified by reverse phase high performance liquid chromatography, and identified by gas chromatography-mass spectrometry. Identified metabolites were four dihydroxyeicosatrienoic acids (DHTs) (5,6-, 8,9-, 11,12-, 14,15-DHTs), 20-hydroxyeicosatetraenoic acid and eicosatetradioic acid. The formation of these metabolites was dependent on NADPH and inhibited by SKF-525A. 14,15-DHT was also formed by isolated bovine adrenal fasciculata cells. These results indicate that cytochrome P-450 dependent arachidonate monooxygenase pathway may exist in bovine adrenal fasciculata cells. Addition of the chemically synthesized epoxyeicosatrienoic acids (EETs) to isolated bovine adrenal fasciculata cells stimulated cortisol production. Among four regioisomeric EETs, 14,15-EET was most potent and stimulated steroidogenesis in a dose-related manner over a range of 0.5 to 5.0 microM.

[Fundamental study of the influence of pixel size on the quality of scintigrams]

The effect of pixel size on image quality was investigated. The image quality was examined by abnormality detection and image preference for clinical images displayed with different pixel sizes. Smaller pixel size was found to be superior to large one in image quality using large field of gamma camera (FWHM 6.42 mm), 1.6mm pixel size (a 256 x 256 matrix) was found to be the best in image quality. Examined image minification effect, 3.2 mm pixel size (image size: 5 cm phi) was found to be superior to 1.6 mm pixel size (image size: 10 cm phi) in image preference and to be almost equal to 1.6 pixel size in abnormality detection.

[Technical study for SPECT of the head using slant hole collimator]

The performance of a 160 keV slant hole collimator (160 keV SH) was compared with that of a 140 keV high resolution collimator (140 keV HR) for SPECT imaging of the head using 99mTc. The minimum radius of revolution was reduced from about 23 cm to 13 cm using 160 keV SH. Relative sensitivity of the 160 keV SH was 108% of that of the 140 keV HR. Compared with SPECT using 140 keV HR, 160 keV SH SPECT yielded approximately a 15% increase in resolution. The 160 keV SH SPECT images of phantom were superior in resolution and contrast to that of 140 keV HR SPECT. We concluded that high quality SPECT images of the head can be obtained from rotating gamma cameras equipped with slant hole collimators.

[Fundamental study for SPECT imaging with 123I produced by (p, 5n) reaction]

The effects of higher-energy photon from 123I (p, 5n) on the SPECT image quality were evaluated. The quality was evaluated by image contrast and %rms. Image contrast had similar tendency to planar and SPECT FWHM value. %rms was affected by septal penetration. Using 140 keV high resolution collimator (140 keV HR), image contrast was superior to that for 300 keV medium energy collimator (300 keV ME), but septal penetration rate (SPR) was 18% and %rms was 10.5. When quantitation is required, the collimator with less SPR than 18% is recommended for SPECT imaging. Using 300 keV ME, SPR was 0.05%, but spatial resolution and image contrast were inferior to that for 140 keV HR.

Ketoconazole as a possible universal inhibitor of cytochrome P-450 dependent enzymes: its mode of inhibition

Modes of inhibition and binding of ketoconazole, an orally antimycotic agent, to NADPH-cytochrome P-450 dependent enzymes were investigated using subcellular fractions of human and rat testes, human adrenocortical adenoma tissue and rat adrenals and livers. Ketoconazole competitively inhibited the activities of steroid 17 alpha-hydroxylase and C17-20 lyase in rat and human testes, 16 alpha-hydroxylase in human testes and 21-hydroxylase in rat adrenal glands. Ki values were in the order of 10(-8)M for human testicular enzymes, while the order was 10(-7)-10(-6) M for rat adrenal and testicular enzymes. Kinetic studies indicated that ketoconazole bound to cytochrome P-450 and not to other components of monooxygenase systems. Spectrophotometric studies also revealed direct binding of ketoconazole to cytochrome P-450 component by inducing type II difference spectra in all tissue preparations examined, indicating that ketoconazole is possibly a universal inhibitor of NADPH-cytochrome P-450 dependent monooxygenases which are involved in metabolism of many substances including steroids, toxins, carcinogens and others.

Preparation of anti-bovine and porcine mu chain sera

Absorption of anti-L chain antibodies contained in anti-IgM sera immunized with purified bovine and porcine IgM was undertaken by affinity chromatography on a column of Sepharose 4B, coupled with the normal follicular fluids of the respective species as an immunosorbent. Anti-L chain antibodies in both anti-IgM sera were completely absorbed without incurring reduction of the antibody titer, and anti-bovine and anti-porcine mu chain sera were prepared.

Isolation of porcine, canine and feline IgG by affinity chromatography using protein A

Isolation of porcine, canine and feline IgG has hitherto been achieved usually by DEAE-ion exchange chromatography and gel filtration. These procedures, however, are rather time-consuming, as they involve purification of IgG. Isolation of IgG by affinity chromatography on a column of protein A-Sepharose was attempted. IgG of all three animal species was very easily isolated with a high yield. In the absence of any other method that allows isolation of IgG of three animal species from a single column, the procedure proposed would be very useful.

[Experimental studies on radiosensitization of hypoxic cancer cells]

Misonidazole was histologically evaluated as a hypoxic cell radiosensitizer to a transplantable human cervical cancer in nude mice (Yumoto Strain). Acute exposure of X-ray (Lineac, a 1,000 rad dose) was applied to the cervical cancer. Tumor Volume (T.V. growth curve). Radiation alone induced an 8-10 day growth delay, but radiation therapy with Misonidazole induced a 10-12 day growth delay. Tumor Cord (T.C.). This idea originated with Thomlinson and Gray. They found that the radius of a tumor cord was always same. On the radiation therapy with Misonidazole, the tumor cords decreased faster than with radiation therapy alone. Tumor cellular Density (T.D.). This is the cell population per unit of area. We separated the tumor cords with two blocks, one near and one far from the blood vessel. T.D. decreased faster in the case of radiation with Misonidazole, and on the far square, radiation effectiveness was more obvious than on the near one. In addition, a histological examination proved that the Misonidazole affected hypoxic elements of the tumor, and this finding was proved in 48 hours after radiation. But aerobic elements of the tumor survived and were slightly changed histologically. In conclusion, Misonidazole proved to be an effective hypoxic cell sensitizer for human cervical cancer in radiation therapy.

Effects of glycerol on sodium and potassium concentrations in guinea pig perilymph

Serum, cerebrospinal fluid (CSF), scala vestibuli perilymph, and scala tympani perilymph were collected from 85 normal guinea pigs both before and after i.v. administration of glycerol (1 ml/kg), and the sodium and potassium concentrations were assessed using a microflame photometer. Marked increases in sodium concentrations were observed in scala tympani perilymph and CSF, while there was a slight decrease in the serum and there was no significant change in scala vestibuli perilymph. These increases in sodium concentrations are considered to occur in the dehydration process in the body fluids mentioned above. On the other hand, increase in the potassium concentrations was found only in scala vestibuli perilymph and thus cannot be explained by simple dehydration process. This potassium elevation in scala vestibuli perilymph should be understood by further experiment on endolymph. It became evident that scala vestibuli perilymph differs from scala tympani perilymph and CSF in the dynamics of electrolytes after glycerol administration. In this regard, the nature of the scala vestibuli as fluid space should be studied in future. The above findings obtained in the present study may imply the significance in elucidating the glycerol effect on hearing of endolymphatic hydrops case.