Quantification of blood flow with dynamic MR imaging and presaturation bolus tracking

A technique is described for rapid imaging of blood flow and dynamic measurement of its velocity. The method is a combination of bolus tracking and low-flip-angle gradient-echo cine angiography. This method provides precise determination of velocity with high temporal resolution in a single measurement. Unlike what occurs in phase imaging techniques, flow is displayed directly, eliminating potential errors that result from non-flow-related sources of phase shifts. Manipulation of raw data sets is avoided. Results obtained from a flow phantom, healthy volunteers, and a patient with an aortic aneurysm demonstrate the capability of the technique to track flow at low and high velocities and to differentiate flowing blood from thrombus. Because of its conceptual simplicity, rapidity, and lack of susceptibility to extraneous phase shifts, this technique may prove ideal for in vivo flow measurement and evaluation of flow patterns.     

The effect of DDAVP on plasma levels of von Willebrand antigen II in normal individuals and patients with von Willebrand's disease

The infusion of 1-deamino-(8-D-arginine)-vasopressin (DDAVP) causes not only an elevation in factor VIII-related antigen (FVIIIR:Ag), but also a marked elevation of plasma von Willebrand antigen II (vWAgII). vWAgII reaches a peak concentration at 60 min and is elevated 3-8-fold over basal levels in normal individuals and individuals with type I, IIA, and IIB von Willebrand's disease. As the mechanism of hemostatic alteration brought about by DDAVP might be due to release of endothelial cell proteins, endothelial cell cultures were performed. The cultures demonstrated synthesis and secretion of vWAgII, as evidenced by the incorporation of 35S-methionine into the vWAgII molecule. Thus, vWAgII, like FVIIIR:Ag, is an endothelial cell protein.     

Localization of surface vWF on resting and stimulated platelets

We used immunoelectron microscopic localization techniques to investigate whether platelets stimulated by ADP or ristocetin in the plasma milieu bind von Willebrand factor (vWF) to their surfaces. We found by both peroxidase- and ferritin-based methods that unstimulated platelets lack vWF on their surfaces, whereas platelets that are stimulated with ADP or ristocetin have vWF associated with their surfaces. The specificity of the findings was confirmed by absorption studies using severe von Willebrand disease (vWD) and hemophilic plasmas. The anti-vWF antibodies were blocked by incubation with hemophilic plasma but not by incubation with severe vWD plasma. Thus, in the plasma environment, in the presence of fibrinogen, vWF becomes associated with the platelet surface subsequent to stimulation with ADP or ristocetin.     

Localization and quantitation of the vitamin D binding protein (Gc- globulin) in human neutrophils

Plasma-derived vitamin D binding protein (DBP) is an important physiologic regulator of the neutrophil chemotactic response to activated complement. A cell-associated form of DBP has been observed in numerous cell types. We now report that mature, circulating human neutrophils also contain cell-associated DBP. Immunofluorescence studies of normal untreated neutrophils showed the presence of DBP on the cell surface. Western blotting of detergent-soluble neutrophil lysates with a polyclonal anti-DBP showed two major immunoreactive bands, one with an apparent molecular weight of 56 Kd (identical to purified plasma-derived DBP) and a second less prominent band at 12 to 14 Kd. Quantitation of the immunoreactive bands by video densitometry indicated that normal human neutrophils contain 1.5 +/- 0.8 ng DBP/10(6) cells (n = 9). Immunoprecipitation of detergent-soluble lysates with the polyclonal anti-DBP showed only the 56-Kd form by Western blotting. In contrast, a monoclonal anti-DBP immunoprecipitated the 12 to 14 Kd form of DBP from lysates of surface-radioiodinated cells. Western blots of subcellular fractions showed that immunoreactive bands were found in the specific (secondary) granule and plasma-membrane fractions. In addition, pretreatment of neutrophils with 10 nmol/L phorbol myristate acetate (PMA) resulted in approximately a 50% reduction in the amount of DBP in both the specific granule and plasma-membrane fractions. Finally, analysis of the cell- free supernates showed that DBP was spontaneously released into the extracellular milieu: moreover, this release was enhanced if the cells were first stimulated with C5a, formyl-norleucyl-leucyl-phenylalanine (fNLP) or PMA.     

Ileo-right hemi-colonic cervical pull-up on a non-supercharged ileocolic arterial pedicle: A technical and case report

Esophageal reconstruction can be challenging when stomach and colon are not anatomically intact and their use as esophageal substitutes is therefore limited. Innovative individual approaches are then necessary to restore the intestinal passage. We describe a technique in which a short stump of the right hemicolon and 25 cm of ileum on a long, non-supercharged, fully mobilized ileocolic arterial pedicle were used for esophageal reconstruction to the neck. In this case, a 65 year-old male patient had accidentally indigested hydrochloric acid which caused necrosis of his upper digestive tract. An emergency esophagectomy, gastrectomy, duodenectomy, pancreatectomy and splenectomy had been performed in an outside hospital. A cervical esophagostomy and a biliodigestive anastomosis had been created and a jejunal catheter for enteral feeding had been placed. After the patient had recovered, a reconstruction of his food passage via the left and transverse colon failed for technical reasons due to an intraoperative necrotic demarcation of the colon. Our team then faced the situation that only a short stump of the right hemi-colon was left in situ when the patient was referred to our center. After intensified nutritional therapy, we reconstructed this patient's food passage with the right hemicolonapproach described herein. After treatment of a postoperative pneumonia, the patient was discharged from hospital on the 26 th postoperative day in a good clinical condition on an oral-only diet. In conclusion, individual approaches for long-segment reconstruction of the esophagus can be technically feasible in experienced hands. They do not always require arterial supercharging or free intestinal transplantation.     

Multicentric Epithelioid Angiosarcoma of the Bone

ABSTRACT: Epithelioid angiosarcoma of the bone represents a challenging diagnosis by bone marrow biopsy. We present a case of a multicentric high grade angiosarcoma of the bone with epithelioid features. On the basis of the clinical presentation, the radiological findings, and the appearance of loosely clustered tumor cells detected in the initial bone marrow biopsy, the main differential diagnoses considered were a poorly differentiated non-secretory multiple myeloma and metastatic carcinoma. Subsequent morphologic, immunohistochemical and electron microscopic examination of tissue samples clarified the nature of the tumor as epithelioid angiosarcoma. We discuss potential pitfalls in clinical and morphological diagnosis. The strong reactivity of the tumor cells with the nonspecific but ubiquitous mesenchymal marker vimentin in similar cases should direct early attention to the rare malignant bone tumor, epithelioid angiosarcoma, with subsequent confirmation of this diagnosis with specific immunohistochemical endothelial cell markers and/or electron microscopy.