Rapid isolation of metaphase chromosomes containing high molecular weight DNA.

Metaphase chromosomes with high molecular weight DNA were isolated from Chinese hamster ovary (CHO) cells in a neutral buffer containing polyamines and chelators. The individual, unfixed chromosomes retained their centromeric and secondary constrictions, distinct sister chromatids, and complex banding patterns. The DNA from these chromosomes was 100-fold larger (2 x 10(8) daltons) than DNA from chromosomes isolated by other procedures. These characteristics indicate preservation during isolation of considerable native structure. In contrast to chromosomes produced by other methods, these chromosomes were stable in storage and did not aggregate, thus providing useful material for studies of the structure and biochemistry of individual chromosomes.

Cruciate ligament injury: diagnostic difficulties in the presence of meniscal injury.

During knee arthrography, the appearance of a mass within the intercondylar notch on the flexed lateral stress radiograph usually indicates a torn cruciate ligament. This mass may also be produced by a torn or peripherally separated meniscus, usually the lateral, that displaces during flexion to lie adjacent to and to obscure the outline of the cruciates. Recognition of this phenomenon is important, both in avoiding the erroneous diagnosis of a cruciate tear and in alerting the arthrographer to the possibility of a peripheral meniscal separation when the ligaments are obscured by a mass.

Pulmonary artery false aneurysms secondary to Swan-Ganz pulmonary artery catheters.

Several complications from the use of balloon-tipped flow-directed (Swan-Ganz) pulmonary artery catheters are recognized. One infrequent but life-threatening complication is false aneurysm formation associated with rupture or dissection of the pulmonary artery. We report 10 cases of catheter-induced pulmonary artery false aneurysms identified during a 9-year period. Initial presentation was radiologic in six patients and clinical (hemoptysis) in four. Later chest radiographic findings consisted of a well-defined, persistent pulmonary nodule or mass (three patients) or focal, dense parenchymal consolidation (six patients) that either persisted (two patients) or evolved into a nodule or mass (four patients) adjacent to the catheter tip. Cavitation of a pulmonary mass developed in one case. Two of eight deaths were caused by pulmonary artery false aneurysm formation and rupture with subsequent fatal hemorrhage. In one patient who survived, the false aneurysm was shown by pulmonary angiography and embolized with coils and Gelfoam. We conclude that pulmonary artery false aneurysms are life-threatening complications of pulmonary artery catheters and have characteristic chest radiographic findings.