Clustering the adhesion molecules VLA-4 (CD49d/CD29) in Jurkat T cells or VCAM-1 (CD106) in endothelial (ECV 304) cells activates the phosphoinositide pathway and triggers Ca2+ mobilization

Ligation of very late antigen (VLA)-4 (α₄β₁ integrin) with a cross-linked anti-α₄ subunit monoclonal antibody (mAb) triggered a biphasic Ca²⁺ response in Jurkat cell populations and in peripheral human lymphocytes. Cross-linking vascular cell adhesion molecule (VCAM)-1 (the counter-receptor of VLA-4) in ECV 304 endothelial cells generated a biphasic Ca²⁺ response. Tumor necrosis factor-α-primed human umbilical cord vascular endothelial cells also responded to the cross-linked mAb with a biphasic Ca²⁺ profile. Ligated VLA-4 (Jurkat cells) or VCAM-1 (ECV 304) stimulated the production of myo-inositol 1,4,5-trisphosphate. ECV 304 cells induced a biphasic Ca²⁺ response in Fura2-loaded Jurkat cells, whereas a transient response was observed when Jurkat cells were added to Fura2-loaded ECV 304 cells. The Ca²⁺ responses in these experiments involved VLA-4/VCAM-1 interactions since they were significantly reduced (～ 80%) by prior treatment of the target cells with the relevant noncross-linked mAb. Close contact between the cells triggered mutual Ca²⁺ signaling as shown by spectrofluorimetric and confocal microscopy time-dependent recordings. Fibronectin and its CS-1 fragment (V25) triggered a sustained Ca²⁺ response in Jurkat cells (confocal microscopy). Our results suggest that the VLA-4 and VCAM-1 adhesion molecules can transduce a signal that involves activation of the phosphoinositide pathway and the mobilization of Ca²⁺.     

Is tranexamic acid safe in patients undergoing coronary endarterectomy?

BACKGROUND: Patients undergoing coronary endarterectomy during coronary artery bypass grafting (CABG) are at increased risk of perioperative myocardial infarction due to coronary intimal disruption. Data assessing the safety of the antifibrinolytic drug tranexamic acid (TA) in patients undergoing this procedure are lacking. METHODS: From September 1997 to December 1999, 221 patients underwent nonemergency primary CABG with endarterectomy of the right coronary artery alone in 149, the left anterior descending in 35, or both right and left anterior descending in 27. TA was administered intraoperatively to 87 patients (TA group: average total dose 62 +/- 4.4 mg/kg; range 20 to 109 mg/kg), and was not administered to 134 patients (No TA group). RESULTS: The patient characteristics of the 2 groups were similar. In-hospital mortality consisted of 2 patients in the TA group and 4 patients in the No TA group. Perioperative myocardial infarction rates were 2% and 5% in the TA and No TA groups, respectively (p = 0.49). The relative risk for any type of perioperative cardiac ischemic event in the TA group versus the No TA group was 0.77 (95% CI; 0.4, 1.2). Patients in the TA group had a significant reduction in postoperative chest tube drainage (685 versus 894 mL in the TA versus No TA groups, respectively) and in the use of fresh-frozen plasma (p = 0.03). CONCLUSIONS: These results suggest that the clinical effectiveness of tranexamic acid in reducing postoperative blood loss in patients undergoing coronary endarterectomy is not associated with a higher incidence of myocardial ischemia-related complications.     

Hémoperitoine spontané pendant la grossesse et anévrysme de l’artère utérine

Spontaneous hemoperitoneum is not frequent. We report here a rare cause of spontaneous hemoperitoneum during the second trimester of pregnancy. A ruptured uterine artery aneurysm was revealed in a patient who came for important abdominal pain. A CT scan showed a large hemoperitoneum and an additional arterial image. The patient underwent rapidly an embolization, which allowed a complete closure of the aneurysm. The patient gave birth to a healthy child. The diagnosis of hemoperitoneum must be discussed without delay. Once imagery realised, a good management of the patient must be done depending on the origin of the hemoperitoneum.     

Utility of peripheral blood cultures in bacteremic pediatric cancer patients with a central line

Purpose  

The utility of peripheral blood cultures in febrile neutropenic children with cancer and central venous catheters (CVC) is controversial. Our primary objective was to describe true bloodstream infections detected only by peripheral culture. Our secondary objectives were to describe true bloodstream infections detected only by CVC culture and to describe probable contaminants detected in both types of blood cultures.     

Practical vaccination guidelines for children with cancer

The paediatrician or family physician usually provides primary care for children diagnosed with cancer. Immunizations are an important facet of this care, but guidelines for the immunization of these immunocom-promised children are difficult to locate and cumbersome to follow. The authors have developed immunization guidelines for children receiving chemotherapy for cancer that will hopefully facilitate the care of this group of children. Before initiating any immunizations in this group of children, communication with a cancer specialist is recommended. There is little evidence-based literature to support immunization guidelines in immunocompromised hosts; thus, the recommendations presented are derived from the available literature, existing guidelines and expert opinion.