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161.
Magnetic resonance (MR) images of the spine and/or intraoperative spinal ultrasound (US) in 24 patients with spinal infections were reviewed and correlated with clinical and pathologic data to determine their diagnostic value. In disk space infection with osteomyelitis and in retrospinal abscess, MR images showed characteristic findings, whereas in myelitis, MR images demonstrated nonspecific abnormalities. The appearance on MR images of epidural abscesses ranged from clearly identifiable extradural masses with high-intensity signal on spin-echo T2-weighted images to extensive inhomogeneous collections of mixed signal intensities, difficult to distinguish from adjacent meningitis. Myelography with high-resolution computed tomography (CT) and intraoperative spinal US was superior to MR imaging in demonstrating epidural abscesses when there was concomitant meningitis. With intraoperative spinal US, epidural abscesses could be located and their decompression monitored. MR imaging is recommended as the initial screening procedure in spinal infection; in those few patients with nondiagnostic MR images, myelography with high-resolution CT should be the supplementary study. If surgery is planned, intraoperative spinal US should be used. 相似文献
162.
2,3-epoxy-4-hydroxynonanal, a potential lipid peroxidation product for etheno adduct formation, is not a substrate of human epoxide hydrolase 总被引:1,自引:0,他引:1
Our previous studies have shown that 2,3-epoxy-4-hydroxynonanal, a reactive
epoxy aldehyde capable of forming etheno adducts with DNA bases, is
mutagenic and tumorigenic (Carcinogenesis, 14, 2073). The epoxy aldehyde
can be generated from trans-4-hydroxy-2-nonenal, a lipid peroxidation
product of omega-6 polyunsaturated fatty acids, by autoxidation or by
incubation with fatty acid hydroperoxides or hydrogen peroxides (Chem. Res.
Toxicol., 9, 306). These are plausible in vivo pathways for the formation
of 2,3-epoxy-4-hydroxynonanal. The possibility that
2,3-epoxy-4-hydroxynonanal is a tumorigen of endogenous origin is suggested
by recent observations that etheno bases are detected as background DNA
lesions in untreated rodents and humans. A metabolic pathway critical for
detoxification of 2,3-epoxy-4- hydroxynonanal involves the ring-opening by
epoxide hydrolase, which abolishes its ability to form cyclic etheno DNA
adducts. In this study, we examined whether 2,3-epoxy-4-hydroxynonanal is a
substrate of cDNA expressed human epoxide hydrolase. Human epoxide
hydrolase was expressed in TK- 143 cells (thymidine kinase-deficient human
embryoblast) infected with recombinant vaccinia virus encoding human
epoxide hydrolase cDNA. Controls consisted of the cells infected with
vaccinia virus in the absence of human epoxide hydrolase cDNA. No
hydrolysis occurred when [2,3-(3)H]2,3-epoxy-4-hydroxynonanal was incubated
at 37 degrees C for 30 min at pH 7.4 with cells expressing human epoxide
hydrolase, as indicated by the presence of a pair of radioactive peaks in
reversed-phase HPLC chromatography, which comigrated with the UV standards
of the two diastereomers of the epoxy aldehyde. The identity of these
compounds as the intact epoxy aldehyde was further supported by
derivatization to the 2,4- dinitrophenylhydrazones followed by reversed
phase HPLC analysis. Similar results were observed with the control cells
or with the heat deactivated human epoxide hydrolase. The epoxide hydrolase
activity in the expressed cells was demonstrated by their ability to
convert benzo[a]pyrene-4,5-dihydroepoxide to benzo[a]pyrene-trans-4,5-
dihydrodiol under the same conditions. These results clearly indicate that
2,3-epoxy-4-hydroxynonanal is not a substrate of human epoxide hydrolase,
and, thus strengthen its possible endogenous role in the formation of
promutagenic exocyclic etheno adducts in vivo.
相似文献
163.
Guckel FJ; Brix G; Schmiedek P; Piepgras Z; Becker G; Kopke J; Gross H; Georgi M 《Radiology》1996,201(2):405
164.
165.
Breast calcifications: analysis of imaging properties 总被引:1,自引:0,他引:1
The imaging characteristics of microcalcifications in both benign and malignant breast conditions were analyzed in 48 digitized film mammograms. Each case included in this analysis had findings considered suggestive of malignancy by the radiologist, with the underlying histologic structure determined by excisional biopsy. Imaging properties of each microcalcification--such as pixel intensity, relative location, distribution, size, and local neighborhood intensities--were recorded. This information was statistically analyzed at the population level according to such selection criteria as histologic type, size of calcification, and cluster size. Distribution ranges were determined for these criteria. Statistical differences between data from benign and malignant cases show the average distance between calcifications in malignant conditions was greater than in benign conditions, and tissue region averages surrounding calcifications associated with malignant conditions were consistently higher than those for benign conditions. 相似文献
166.
Intraabdominal adhesions: intraoperative US 总被引:1,自引:0,他引:1
167.
FJ Ramos-Gomez 《Oral diseases》1997,3(Z1):S31-S35
Most infants with congenital HIV infection appear normal at birth. Clinical difficulties usually begin as the first year proceeds, and in about half of the children oral manifestations are the first signs. Oral manifestations are commonly found in HIV-positive asymptomatic and pediatric AIDS patients, they are the earliest clinical signs of HIV infection and disease progression in children, and may be used as diagnostic markers, especially in developing countries. Studies have established an accurate association between oral manifestations and progression of HIV disease in children. Since the mouth is easily accessed for clinical examination, the important oral signs should be utilized in the diagnosis and early intervention of AIDS in these vulnerable populations. 相似文献
168.
This study aims (i) to ascertain whether oxidative-stress-induced
disturbances in chromosomal distribution in the metaphase-II spindle of
mouse oocytes can be counteracted by supplementing culture medium with
antioxidants; and (ii) to determine whether supplemental intake of
antioxidants neutralizes the disturbing effects of maternal ageing on
segregation of chromosomes during the first meiotic division and
distribution of chromosomes in the metaphase-II spindle. (i): Germinal
vesicle oocytes from unstimulated 10-12 week old mice were matured in vitro
in the presence or absence of diamide and/or dithiothreitol. Metaphase-II
oocytes were fixed and stained with 4',6-diamidino-2- phenylindole (DAPI)
to detect abnormalities in chromosomal distribution. The percentage of
oocytes arrested in metaphase I (12.9% vs 28.4%; P < or = 0.05) or with
a telophase-I chromosome configuration (0.0% vs 8.2%; P < or = 0.0005)
was decreased in diamide-DTT-treated oocytes when compared to
diamide-treated oocytes. (ii): Mice were fed, from the first day of weaning
until their death, a diet supplemented or not with an antioxidant mixture
of vitamin C and vitamin E. Ovulated oocytes were fixed and stained with
DAPI or C-banded for chromosome analysis. The percentage of abnormal
(chromosome scattering and nulloploidy) or asynchronous (anaphase I or
telophase I) oocytes was 2.7-fold higher in controls than in females fed an
antioxidant diet (24.4% vs 8.9%, P < or = 0.05). Furthermore, the
percentage of aneuploidy (2.2% vs 0.0%; P < or = 0.01) and diploidy
(5.8% vs 1.7%; P < or = 0.05) was significantly higher in controls than
in females fed an antioxidant diet. These findings support Tarin's
oxidative stress hypothesis of aneuploidy and have clinical implications
for preventing both laboratory-induced and maternal-age-associated
aneuploidy in human beings.
相似文献
169.
Identification of mutations in two major mRNA isoforms of the Chediak- Higashi syndrome gene in human and mouse 总被引:4,自引:1,他引:4