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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

774 records · Page 43Linked to original sources
PubMedDate not supplied

Basilar artery fenestrations detected by MR angiography.

Basilar artery (BA) fenestrations are the most frequently observed fenestrations of the cerebral arteries. Our goal was to examine the magnetic resonance (MR) angiographic incidence, location, and characteristic configuration of BA fenestration. Between April 1996 and March 2000, 600 cranial MR angiographies were performed at our institution. The majority of the patients examined had or were suspected to have cerebrovascular disease. We retrospectively reviewed these 600 MR angiograms. A 1.5 Tesla scanner was used in all studies, and maximum intensity projection (MIP) images obtained using the three-dimensional time-of-flight (3D-TOF) technique were displayed stereoscopically. Ten BA fenestrations (1.7%) were detected on MR angiograms. In 87 cases from the early period, the vertebrobasilar (VB) junction was unfortunately not included in the imaging slices. Eight of the 10 fenestrations were located at the proximal BA: six of them were small with a slit-like shape, and two were relatively large with a convex-lens-like shape. A small fenestration was located at the distal BA, and the remaining one was a total duplication of the BA. We stress that knowledge and recognition of BA fenestration are useful and important in the interpretation of cranial MR angiography. Since saccular aneurysms are reported to arise frequently at BA fenestration, the VB junction should be included in the imaging slices of routine cranial MR angiography.

Basilar Artery↗
PubMedDate not supplied

Differentiation of oncogenic and nononcogenic strains of Marek's disease virus type 1 by using polymerase chain reaction DNA amplification.

Differentiation of oncogenic and nononcogenic strains of Marek's disease virus type 1 (MDV1) was attempted by polymerase chain reaction (PCR) using the primers chosen from the sequence within the long inverted repeats of MDV1 DNA. PCR of the DNAs extracted from oncogenic-strain-infected cells and Marek's disease tumor cell lines produced a major product containing two or three copies of 132-base-pair (bp) repeat units, whereas PCRs of the DNAs extracted from nononcogenic-strain-infected cells yielded amplified products with various sizes corresponding to the number of 132-bp repeat units. The primers chosen from the glycoprotein A genes of MDV1 and herpesvirus of turkeys also were used for determination of their serotype specificity. The PCR procedure was found to be a simple and sensitive procedure for identification of MDV1 and herpesvirus of turkeys and for estimation of oncogenicity of MDV1.

Base Sequence↗
PubMedDate not supplied

Digital subtraction angiography for leg venography.

Venography was performed in 25 legs of 17 patients using digital subtraction angiography (DSA). Reliable diagnoses of deep vein thrombosis or patency were made in the majority of these cases. There were no complications. Multiple injections of contrast material were required to image the entire leg; however, the total quantity of iodine necessary for each leg averaged 9 g, significantly less than with conventional techniques. The preferred method consisted of injecting 15 ml of 100 mg iodine/ml contrast material followed by 15 ml of heparinized saline. DSA proved a safe and useful means of evaluating veins of the leg.

Aged↗
PubMedDate not supplied

Nipple discharge cytology in mass screening for breast cancer.

Since 1977 mass screening for breast cancer has been conducted in Miyagi Prefecture, Japan; inspection, palpation and cytologic examination of any nipple discharge are part of the initial screening procedures. Among 149,681 subjects examined, 404 cancer cases and 63 papilloma cases were detected. The nipple discharges from 20,537 women were examined cytologically; of the 61 cancer cases, the smears were positive in 18 cases, suspicious in 7, negative with atypical findings in 12 and negative in 24. Ten of the cancer cases were detected exclusively by the cytologic examination of a nipple discharge. In eight of these ten cancer cases, there was no other initial evidence of the primary tumor. The cytologic diagnosis of discharges without blood from 28 cancer cases was positive or suspicious in 10 cases and negative in 18. Thirty-seven of the papilloma cases were initially detected only by the cytologic examination of a nipple discharge; neither physical examination nor mammography showed any abnormal findings.

Adult↗
PubMedDate not supplied

(+)Nortrachelogenin, a new pharmacologically active lignan from Wikstroemia indica.

A new lignan, (+)-nortrachelogenin (I), and a known compound, daphnoretin were isolated from Wikstroemia indica C.A. Meyer (Thymelaeaceae). The structure of (+)-nortrachelogenin was established as 8(R)8'-4,4',8'-trihydroxy-3,3'-dimethoxylignan-olid, (9,9') on the basis of spectroscopic evidence and comparison with its enantiomer, (-)-nortrachelogenin. +-nortrachelogenin(I) showed effects on the central nervous system producing depression in rabbits.

Animals↗
PubMedDate not supplied

(+)-Nortrachelogenin, a new pharmacologically active lignan from Wikstroemia indica.

A new lignan, (+)-nortrachelogenin (I), and a known compound, daphnoretin were isolated from Wikstroemia indica C. A. Meyer (Thymelaeaceae). The structure of (+)-nortrachelogenin was established as 8(R), 8'(R)-4,4',8'-trihydroxy-3,3'-dimethoxylignan-olid(9, 9') on the basis of spectroscopic evidence and comparison with its enantiomer, (-)-nortrachelogenin. (+)-Nortrachelogenin (I) showed effects on the central nervous system producing depression in rabbits.

Animals↗
PubMedDate not supplied

Disposition and pharmacokinetics of a polymeric prodrug of mitomycin C, mitomycin C-dextran conjugate, in the rat.

The disposition and pharmacokinetics of a polymeric prodrug of mitomycin C (MMC), mitomycin C-dextran conjugate (MMCD), following iv bolus administration was studied in rats. Three types of MMCD, conjugates with dextran of molecular weights of 10,000, 70,000, and 500,000, were tested and disposition of carrier dextran and MMC was determined by 14C radioactivity counting and bioassay, respectively. Radioactivity was accumulated in the reticuloendothelial system such as the liver, spleen, and lymph nodes after injection of all three types of 14C-MMCD, but not in the lung, heart, and muscle. Renal distribution of 14C-MMCD varied with the molecular size of the carrier. After injection of cold MMCD, plasma concentrations of MMC in the free and conjugated forms were determined separately on the bases of bioassay. Similar sustained plasma levels of MMC were detected regardless of the carrier size although the concentration-time profiles of MMCD varied with the size of dextran. These plasma concentration data were fitted to a compartment model including a first order conversion process from MMCD to MMC in the central and peripheral compartments of MMCD. Kinetical analysis revealed that MMCD acts as a reservoir of MMC which behaves characteristically as a macromolecule while supplying active MMC in the body.

Animals↗
PubMedDate not supplied

Direct correlation between the titer of infectious bursal disease virus VP2-specific antibody and protection.

The titer of antibody specific to infectious bursal disease virus (IBDV) was measured by a new method and correlated with protection. Challenge was carried out in chickens with various antibody titers, which were measured using a latex agglutination-inhibition (LI) test, a rapid and easy technique for measuring IBDV VP2-specific antibody. When actively immunized chickens had LI titers of 1:2 or more, almost all were protected from subsequent challenge with highly virulent IBDV. In contrast, even when chickens passively immunized with maternally derived antibody had LI titers of 1:4, half were susceptible to the same challenge.

Agglutination Tests↗
PubMedDate not supplied

Rapid and quantitative assay system for measuring anti-infectious bursal disease virus antibody using monoclonal antibody bound to polystyrene latex microspheres.

A monoclonal antibody (MAb) to infectious bursal disease virus (IBDV) that has virus-neutralizing activity was bound to polystyrene latex microspheres The microspheres agglutinated with extracts of bursae from chickens infected with IBDV. Agglutination was inhibited in a competitive manner by adding serum obtained from IBDV-infected chickens. The level of agglutination-inhibition depended on the serum antibody titer against IBDV. The reaction was visually accomplished within 5 minutes. The titer of this rapid assay showed a close relationship with that of the virus-neutralization test.

Animals↗
PubMedDate not supplied

Sequence comparisons of a highly virulent infectious bursal disease virus prevalent in Japan.

Variable cDNA regions in the VP2 gene of five highly virulent infectious bursal disease viruses (IBDVs) isolated in Japan were amplified by polymerase chain reaction (PCR) and sequenced. The nucleotide sequences of five highly virulent IBDVs were identical. Comparisons of the nucleotide and the deduced amino acid sequences with those of other strains of IBDV indicated that Japanese highly virulent IBDV is different from all other strains of IBDV that were compared. The number of amino acids that differed between strains (substitution score) showed that highly virulent IBDV is more closely related to European virulent strain 52/70 than to Japanese conventional strains. These results strongly suggest that a single strain of highly virulent IBDV that might have originated from a European strain is prevalent in Japan.

Amino Acid Sequence↗
PubMedDate not supplied

Clinicopathologic features of early hepatocellular carcinoma.

BACKGROUND/AIMS: This study attempts to clarify the clinicopathologic definition of early hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: We evaluated 57 patients, with HCCs less than 3 cm in diameter, in terms of prognosis, incidence of extrahepatic metastasis, and tumor recurrence rate following treatment. RESULTS: Survival was related to both tumor number and histologic differentiation, but was not related to tumor size. Furthermore, prognosis appeared to depend on the functional reserve of the liver. The incidence of extrahepatic metastasis was related to histologic differentiation. There was no significant difference in the recurrence rates of patients with uninodular tumors in terms of tumor size. CONCLUSIONS: Our findings indicate that early HCCs measure 15 mm or less in diameter, are uninodular, and are histologically well-differentiated. Finally, the functional reserve of the liver will likely be an additional parameter that will further characterize early HCCs.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

MR imaging of idiopathic trigeminal neuralgia: correlation with non-surgical therapy.

Magnetic resonance (MR) findings in patients with idiopathic trigeminal neuralgia were evaluated and correlated with the effectiveness of non-surgical treatments. Thirty-four patients with idiopathic trigeminal neuralgia (ITN) were examined using T1- and T2-weighted spin-echo (SE) pulse sequence techniques to evaluate their trigeminal root-entry zones and the vessels contacted prior to non-surgical treatment (retrogasserian glycerol injection, peripheral nerve block, or only oral analgesics). Vascular contact at the proximal portion of the preganglionic segment (PGS) of the trigeminal nerve and deformity of the PGS on the affected side were observed in 97% and 47% of the patients, respectively. Non-surgical treatments were curative in 12 (67%) but failed in two (11%) of the 18 patients without deformed PGS. However, among 16 patients with deformed PGS, they were curative in only six (37.5%) and failed in four (25%). Results of this study suggest that MR imaging could be useful in the clinical assessment of trigeminal neuralgia prior to instituting non-surgical treatment.

Administration, Oral↗
PubMedDate not supplied

Keishi-ka-kei-to, a traditional Chinese herbal medicine, inhibits pulmonary metastasis of B16 melanoma.

Keishi-ka-kei-to, a traditional Chinese herbal medicine composed of a mixture of crude extracts from five medicinal plants (Cinnamomi cortex, Paeoniae radix, Zizyphi fructus, Zingiberis rhizoma and Glycyrrhizae radix), inhibited experimental pulmonary metastasis in mice implanted with B16F10 melanoma cells. When 136 to 145 metastatic colonies were produced in lungs of mice inoculated with 1 x 10(5) cells/mouse of melanoma cells, less than 15 metastatic colonies were demonstrated when these tumor-inoculated mice were treated orally with 80 to 320 mg/kg doses of Keishi-ka-kei-to. The most active component in the mixture was shown to be 6-gingerol, derived from the Zingiberis rhizoma extract. The antimetastatic activity of 6-gingerol was expressed through the host's antitumor immune functions, as the growth of B16F10 melanoma cells was not affected by this substance in vitro. The splenic CD8+ T cells from mice treated with the compound showed inhibitory activities on pulmonary metastasis when these T cells were adoptively transferred to mice bearing B16F10 melanoma cells. These results may suggest that Keishi-ka-kei-to inhibits pulmonary metastasis in mice bearing B16F10 melanoma cells through the stimulation of CD8+ T cells.

Animals↗
PubMedDate not supplied

Computed radiography angiography using storage phosphor imaging plates: eight year's experience.

We reviewed the indications, modalities, and quality of angiographic examinations performed in our department from 1987 to 1994 and compared the image characteristics and technical convenience of three modalities: conventional film-screen angiography, fluorographic digital subtraction angiography (F-DSA), and computed radiography angiography using biplane rapid changers of storage phosphor imaging plates (IP-CRA). IP-CRA has practically eclipsed conventional film-screen angiography in our radiology department. Sixty-percent of the total 700 examinations carried out in 1994 were performed using a combination of IP-CRA and fluorographic digital subtraction angiography (F-DSA). The remainder were performed with F-DSA alone. The post-processing functions of IP-CRA like subtraction and change of contrast or density were useful especially in such regions as pulmonary, bronchial, or external carotid arterial territories, where high natural contrast made image processing difficult with both F-DSA and film-screen angiography. The spatial resolution of IP-CRA was superior to that of F-DSA and comparable to the film-screen method. It was concluded that angiography using imaging plates was a useful part of the digital radiography system.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Dural ectasia of the optic nerve sheath in neurofibromatosis type 1: MRI manifestations.

Patients with neurofibromatosis type 1 (NF-1) have an increased incidence of optic glioma. Although spinal dural ectasia or meningocele is well represented in the NF-1 literature, radiologists are not as familiar with dural ectasia of the optic nerve sheath as spinal dural ectasia. This is a report of a pediatric patient with NF-1 with dural ectasia of the optic nerve sheath. This is the second reported case of dural ectasia of the optic nerve sheath demonstrated by magnetic resonance imaging.

Cheek↗
PubMedDate not supplied

CT angiography using electron-beam computed tomography (EBCT): a phantom study.

The purpose of this study was to evaluate the accuracy of CT angiography in small vessels using electron-beam computed tomography (EBCT). Vessel phantoms with inner diameters of 8 mm, 6 mm, and 4 mm were prepared with segments of 75%, 50%, and 25% stenosis in each vessel. The vessels were filled with contrast medium (Iopamidol 300 at 1/24 dilution, approximately 380 HU). The EBCT apparatus used was an Imatron C- 150. The step volume scan mode was used with slice thicknesses of 1.5 mm and 3.0 mm, scan time of 0.3 sec, and 210 mm field of view. Images with a slice thickness of 1.5 mm were definitely better than those with a slice thickness of 3.0 mm. The quality of maximum intensity projection (MIP) images was quite similar to that of three-dimensional (3D) images. Using the 8 mm vessel phantom, all stenotic segments were accurately visualized on CT angiography. The 50% stenotic segments were accurately estimated in all vessels. However, the 75% stenotic segments were slightly overestimated in smaller vessels, and the 25% stenotic segments were slightly underestimated in smaller vessels. We consider CT angiography using EBCT to be a useful, less invasive diagnostic modality for stenoocclusive lesions.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Plain CT findings of brain death confirmed by hollow skull sign in brain perfusion SPECT.

Computed tomographic (CT) findings of 13 patients manifesting brain death were reviewed. This diagnosis was confirmed by the so-called "hollow skull" pattern observed in brain perfusion single photon emission computed tomography (SPECT), which was performed between 4 hours before and 3 days after the CT scans, and by subsequent corporal death. The brain perfusion SPECT was performed with the intravenous administration of technetium (Tc)-99m-hexamethylpropyleneamine oxime (HMPAO) or iodine (I)-123-N-isopropyl-p-iodoamphetamine (IMP). CT scans showed diffuse cerebral edema and the loss of gray-white matter differentiation in all the cases, and transtentorial herniation in 12 patients. These CT findings were considered predictive of brain death.

Adolescent↗