Pulmonary arteriovenous malformations: techniques and long-term outcome of embolotherapy

Over a 10-year period, 276 pulmonary arteriovenous malformations (PAVMs) were occluded with balloon embolotherapy in 76 patients, 67 (88%) of whom had hereditary hemorrhagic telangiectasia. Eleven patients (14%) were discovered by means of family screening with measurement of arterial blood gases and chest radiography. Epistaxis, dyspnea, hemoptysis, and hemothorax occurred in 79%, 71%, 13%, and 9% of patients, respectively. Clinical histories of strokes and transient ischemic attacks were present in 18% and 37% of patients, respectively. Computed tomographic scans of 59 patients showed stroke in 36%. Sixty-five percent of PAVMs were located in the lower lobes, which correlated with the finding of more pronounced hypoxemia in the upright position. After embolotherapy, symptomatic hypoxemia was corrected, and serial values have remained constant for 5 years. Complications were minimal, and no patient required surgery. Balloon embolotherapy is effective long-term therapy for PAVMs, and family screening should be pursued because of the possibility of a higher frequency of paradoxical embolization (stroke) than previously recognized.     

The STRO-1+ fraction of adult human bone marrow contains the osteogenic precursors

The monoclonal antibody STRO-1 identifies clonogenic bone marrow stromal cell progenitors (fibroblast colony-forming units [CFU-F]) in adult human bone marrow. These STRO-1+ CFU-F have previously been shown to give rise to cells with the phenotype of fibroblasts, adipocytes, and smooth muscle cells. In this study, the osteogenic potential of CFU- F derived from the STRO-1+ fraction of adult human bone marrow was determined. CFU-F were isolated from normal bone marrow aspirates by fluorescence activated cell sorting, based on their expression of the STRO-1 antigen. Osteogenic differentiation was assessed by the induction of alkaline phosphatase expression, by the formation of a mineralized matrix (hydroxyapatite), and by the production of the bone- specific protein osteocalcin. STRO-1+ cells were cultured in the presence of dexamethasone (DEX; 10(-8) mol/L), ascorbic acid 2- phosphate (ASC-2P; 100 mumol/L), and inorganic phosphate (PO4i; 2.9 mmol/L). After 2 weeks of culture, greater than 90% of the cells in each CFU-F colony stained positive for alkaline phosphatase using a monoclonal antibody specific for bone and liver alkaline phosphatase. Alkaline phosphatase activity was confirmed by histochemistry. A mineralized matrix developed in the CFU-F cultures, after 4 weeks of culture in the presence of DEX, ASC-2P, and PO4i. Mineralization was confirmed by both light and electron microscopy. The mineral was identified as hydroxyapatite by electron dispersive x-ray microanalysis and by x-ray diffraction analysis. In replicate cultures, osteocalcin release was shown after exposure of the cells to 1,25-dihydroxyvitamin D3 (10(-7) mol/L) both by radioimmunoassay and Northern blot analysis. This work provides direct evidence that adult human bone marrow-derived CFU-F are capable of differentiating into functional osteoblasts and that osteoprogenitors are present in the STRO-1+ population.     

Scintigraphy with In-111-labeled monoclonal antitumor antibodies: kinetics, biodistribution, and tumor detection

The purpose of this study was to evaluate and compare the kinetics, biodistribution, and tumor-depicting properties of three intact indium-111-labeled murine monoclonal antibodies (MoAb) and to determine if use of In-111-labeled F(ab')2 fragments of one of them had advantages over its intact counterpart for immunoscintigraphy. Ten patients with prostate cancer were studied with an anti-prostatic acid phosphatase MoAb (PAY-276), with a resultant tumor detection rate of 15%. Twenty-eight patients with melanoma were studied with ZME-018, a MoAb that targets the KD-240 melanoma antigen. Forty-three percent of the known lesions were detected. Forty patients with carcinoembryonic antigen (CEA)-producing tumors were studied, 24 with intact ZCE-025, and anti-CEA MoAb, and 16 with its F(ab')2 fragment. With use of intact ZCE-025, 34% of known lesions were detected versus 83% with its F(ab')2 fragment. The distribution of each MoAb appears unique unto itself with regard to kinetics, normal tissue distribution, and response to MoAb mass.     

Distal esophageal ballooning following Heller myotomy

Eccentric ballooning of the distal esophagus was observed radiographically in 11 of 23 patients (48%) who underwent Heller myotomy for achalasia. While, to the authors' knowledge, ballooning at the site of myotomy incision has not been described previously in the radiologic literature, it should be recognized as a normal and frequent postoperative finding. Radiologists should be aware of this finding so that it is not mistaken for postoperative abnormalities following esophagomyotomy or an epiphrenic diverticulum.