Chemical-shift imaging: a hybrid approach

The hybrid technique of projection-reconstruction echo-planar (PREP) imaging for obtaining chemical-shift images is demonstrated experimentally using a fluorine sample. The technique which is a variation on echo-planar imaging (EPI) relies on a multipass procedure. It is nevertheless quite efficient and consequently chemical-shift images may be produced in a few minutes. The method produces images in 64 chemical-shift regions, each region mapped spatially by 64 X 64 pixels. The imaging time was just over 4 min. These 64 chemical-shifted images can be straightforwardly added together to form an undistorted image of the complete object. In addition the chemical-shift spectrum can be extracted and the various chemical-shift images can be unambiguously assigned to the spectral peaks.     

Trypanosome variant surface glycoproteins are recognized by self-reactive antibodies in uninfected hosts.

The variant surface glycoproteins (VSGs) of African trypanosomes form a dense surface coat on the bloodstream parasites. VSGs are immunodominant antigens that stimulate a rapid antibody response in trypanosome-infected individuals. In the present study, we examined VSG-specific antibodies present not only in sera from infected individuals but also in sera from individuals that had never been exposed to trypanosomes. Native antibodies against different VSGs were detected in sera from uninfected mice, bovines, and humans; the antibodies were revealed to be exclusively directed against variable determinants of the antigens. Further experimentation demonstrated that such native antibodies immunoreact with cellular components of mice and thus are most likely produced by the self-reactive B-cell compartment of the murine immune system.     

Remotely inserted venous occlusion catheters for the control of venous haemorrhage.

This paper describes the use of venous occlusion catheters inserted via the long saphenous vein or its tribularies for control of major retroperitoneal venous haemorrhage. The technique has been applied successfully in 10 cases of trauma and aortocaval fistula. Exposure and insertion are simple and quick and a measure of control is obtained before exposure of the injury which can then be completely repaired before deflation of the balloon and withdrawal of the catheter.     

Impact of Induction Chemotherapy and Preoperative Chemoradiotherapy on Operative Morbidity and Mortality in Patients with Locoregional Adenocarcinoma of the Stomach or Gastroesophageal Junction

Background Significant tumor downstaging has been achieved in patients with localized gastric or gastroesophageal adenocarcinoma by induction chemotherapy and preoperative chemoradiotherapy (CTX–CTXRT). However, the influence of CTX–CTXRT on operative morbidity and mortality has not yet been clarified. The aim of the present study was to document the frequency and nature of morbidity and mortality after surgery combined with CTX–CTXRT, and identify factors predictive of postoperative complications in patients with localized gastric or gastroesophageal adenocarcinoma. Methods A prospectively collected database on 71 consecutive patients who underwent CTX–CTXRT at M.D. Anderson Cancer Center between January 1997 and August 2004 was reviewed. Postoperative morbidity and mortality were investigated, and risk factors for overall complications were identified by multivariate logistic regression analysis. Results Overall morbidity and mortality rates were 38.0% (27 patients) and 2.8% (2 patients), respectively. Age greater than 60 years [relative risk 11.3 (95% confidence interval 2.50–50.6)] and body mass index (BMI) of 26 kg/m² or above [relative risk 4.08 (95% confidence interval 1.08–15.4)] were significant risk factors for overall complications. Conclusions CTX–CTXRT can be performed safely with an acceptable operative morbidity and a low operative mortality rate in patients with gastric or gastroesophageal cancer, with careful consideration of added risk associated with age and obesity.     

The synthesis and localization of alternatively spliced fibronectin EIIIB in resting and thrombin-treated megakaryocytes

There are several species of alternatively spliced fibronectin (FN). One of these, FN EIIIB, is primarily present in embryonic and in proliferating and migrating cells and is believed to be important for cell maturation. We have studied the synthesis, localization, and secretion of this FN isoform in isolated guinea pig megakaryocytes, nonmegakaryocytic bone marrow cells, and platelets. There was 7.5 times more general FN in megakaryocytes than in nonmegakaryocytic cells based on the analysis of equivalent amounts of protein. FN EIIIB was detected by Western blotting in megakaryocytes but not in nonmegakaryocytic cells present in bone marrow. Neither megakaryocytes nor platelets secreted FN EIIIB, while megakaryocytes secreted 25.3% +/- 4.6% general FN and platelets secreted about 61% general FN in response to thrombin. Analysis of immunostained cells by confocal microscopy revealed that FN EIIIB had been redistributed to the surface of megakaryocytes in response to thrombin. Synthesis was studied by metabolic labeling, and megakaryocytes were shown to synthesize FN and FN EIIIB. Thus, megakaryocytes and platelets are among a small number of adult cells and tissues that synthesize and contain FN EIIIB. The expression of FN EIIIB on the megakaryocyte surface may influence migration and maturation.