Quantitative US attenuation in normal liver and in patients with diffuse liver disease: importance of fat

Two methods are used to estimate ultrasound attenuation in liver. These were based on amplitude change and frequency change as a result of depth dependent attenuation. Evaluation of the two methods against a family of calibrated phantoms yielded correlation coefficients of 0.98 and 0.99, respectively. Liver attenuation in 26 control subjects was 0.50 and 0.52 dB/MHz/cm, respectively. Liver attenuation was estimated in 50 patients who later underwent liver biopsy. Comparison with quantitative histologic results showed that the presence of fat alone accounted for the increased attenuation associated with cirrhosis. Similar high attenuation values were found in patients with fatty infiltration. Fibrosis alone did not result in elevated liver attenuation. Cirrhotics without fatty infiltration had attenuation similar to that of the controls. Mechanisms of action are discussed.     

Calcification in pulmonary nodules: detection with dual-energy digital radiography

The authors undertook a clinical study to determine the accuracy of dual-energy digital radiography in revealing nodule calcification because calcification in a pulmonary nodule almost excludes the possibility of malignancy. Over a 6-month period, 61 patients with pulmonary nodules (less than or equal to 3 cm) or masses (greater than 3 cm) were examined on a prototype scanned projection unit using a dual-energy detector. In 49 of 61 patients, nodules were noncalcified, and in 12, they were calcified. In 57 patients, the benignancy or malignancy of nodules was established beyond reasonable doubt by pathologic confirmation in 38 and by strong inference in 19 (four patients with noncalcified solitary pulmonary nodules either refused further investigation or surgery or their follow-up was too short to permit exclusion of malignancy). Dual-energy radiography was found to be highly accurate in assessing the presence or absence of calcification in pulmonary nodules and thus in determining their benignancy or possible malignancy.     

Isolation and characterization of complement receptors CR1 from human peripheral nerves

Extracts from myelinated and unmyelinated nerves, prepared using Nonidet P-40, contained receptors for C3b/C4b (CR1). Extracts from myelinated nerves inhibited EAC3b rosette formation with peripheral blood leucocytes and agglutinated EAC3b, whereas extract from unmyelinated nerves did not. Rosette formation with EAC3bi or EAC3d was not affected. CR1 in extracts from myelinated nerves also expressed decay-accelerating activity of the alternative pathway C3 convertase and cofactor activity in factor I-mediated cleavage of C3b, whereas CR1 in extract from unmyelinated nerves did not. Monoclonal anti-CR1 antibodies, but not monoclonal anti-CR2 (C3d receptors) or anti-CR3 (C3bi receptors) antibodies inhibited the functional activities. Accordingly, CR1 are the only C3 receptor present in the extracts and only CR1 in myelinated nerve extracts are functionally active. CR1 in both myelinated and unmyelinated nerve extracts had a molecular weight of approximately 190 kDa. The electrophoretic mobility did not change after reduction and the 190 kDa band was stained by concanavalin A, indicating that the CR1 are single-chained glycoproteins. Binding to lentil lectin-Sepharose 4B further sustained the glycoprotein nature of the CR1. Periodic acid abolished functional activities of CR1, whereas trypsin and heat did not, indicating the functional significance of the carbohydrate moiety. That CR1 are functionally active in myelinated nerves, but not in unmyelinated nerves, may therefore be due to differences in the carbohydrate moiety. The cofactor and decay-accelerating activities of CR1 may be of significance in the pathogenesis of demyelinating polyneuropathies by limiting complement activation.     

Pseudoportal Doppler signal in the partially obstructed inferior vena cava

The Doppler spectrum of the normal inferior vena cava (IVC) shows a majority of flow toward the right atrium, with wide variations in flow velocity and direction owing to effects of the cardiac and respiratory cycles. Seventeen subjects underwent duplex sonography: nine children after liver transplantation, two children with right upper quadrant neuroblastoma, and six healthy control subjects. In six children the spectrum obtained from the IVC bore a strong resemblance to the unidirectional, low-velocity, continuous-flow pattern associated with the portal vein; these children included two children with biliary atresia and cirrhosis, two liver transplant recipients, and two children with IVC compression by neoplasm. In healthy children and adults, a pseudoportal Doppler signal in the IVC can be generated by subcostal right upper quadrant compression. The pseudoportal IVC appears to be a sign of partial IVC obstruction. Knowledge of this potential pitfall and meticulous morphologic imaging can help prevent mistaking the IVC for a patent portal vein.     

Long-range mapping of the Philadelphia chromosome by pulsed-field gel electrophoresis

The Philadelphia chromosome (Ph1) of chronic myelogenous leukemia (CML) contains sequences from chromosome 9, including the ABL protooncogene, that have been translocated to the breakpoint cluster region (bcr) of chromosome 22, giving rise to a bcr-ABL fusion gene, whose product has been implicated in the genesis of CML. Although chromosome 22 translocation breakpoints in CML virtually always occur within the 5.8- kilobase (kb) bcr, chromosome 9 breakpoints have been identified within the known limits of ABL in only a few instances. For a better understanding of the variability of the breakpoints on chromosome 9, we studied the CML cell line BV173. Using pulsed-field gel electrophoresis (PFGE), large-scale maps of the t(9;22) junctions were constructed. The chromosome 9 breakpoint was shown to have occurred within an ABL intron, 160 kb upstream of the v-abl homologous sequences, but still 35 kb downstream of the 5'-most ABL exon. bcr-ABL and ABL-bcr fusion genes were demonstrated on the Ph1 and the 9q+ chromosomes, respectively; both of these genes are expressed. These results suggest that the 9;22 translocation breakpoints in CML consistently occur within the limits of the large ABL gene. RNA splicing, sometimes of very large regions, appears to compensate for the variability in breakpoint location. These studies show that PFGE is a powerful new tool for the analysis of chromosomal translocations in human malignancies.     

介入化疗在宫颈癌近期疗效的观察

目的：探讨髂内动脉化疗或子宫动脉化疗栓塞在宫颈癌治疗中的意义。方法：给82例宫颈癌患者做髂内动脉化疗或子宫动脉化疗栓塞加放疗共97次，为观察组，另外选择与上述分期相近的81例为对照组。观察并评定各组疗效。结果：观察组CR23例，PR45例，SD9例，PD5例，有效率82．9％。其中11例介入治疗后手术。对照组，CR16例，PR38例，SD23例，PD4例，有效率66．6％。结论：髂内动脉化疗或子宫动脉化疗栓塞作为宫颈癌的辅助治疗行之有效，能缩小原发病灶，尽快缓解临床症状，与放疗结合，可提高治疗效果，具有较好的临床价值。     

Bony spinal canal changes that differentiate conjoined nerve roots from herniated nucleus pulposus

CT examinations of the lumbar spine in 12 consecutive patients with conjoined nerve roots were reviewed. Asymmetry of the bony spinal canal, seen as slight dilatation of the ipsilateral lateral recess, was present in all cases. This finding, which is not typically associated with extruded free intervertebral disk fragments, should serve to distinguish these two entities.