Flow-cytometric detection of terminal deoxynucleotidyl transferase and other intracellular antigens in combination with membrane antigens in acute lymphatic leukemias

Development of a new fixation procedure allowed flow-cytometric analysis of nuclear and other intracellular antigens in acute lymphatic leukemia (ALL). A short fixation of the cells with buffered formaldehyde acetone (BFA) rendered the cell membrane permeable, allowing the monoclonal antibodies (MoAbs) to penetrate the cell. Through this method, a rapid analysis of intracellular antigens, specific for acute lymphatic leukemia [such as terminal deoxynucleotidyl transferase (TdT), immunoglobulin M (IgM) heavy chain, and antigens recognized by the CD22 or CD3 MoAbs) was performed by flow cytometry. The surface antigens remained intact after this fixation procedure, enabling simultaneous detection of membrane and intracellular antigens. The binding of biotinylated antibodies against several B- and T-lymphoid membrane antigens was detected with streptavidin-phycoerythrin (red fluorescence), whereas the intracellular antigens were stained with FITC-labeled polyclonal antibodies, or indirectly with FITC-labeled goat anti-mouse IgG (green fluorescence). Through this combination of markers, minor cell populations can be detected and a rapid and quantitative immunodiagnosis can be performed.     

Preparation of the Critically III for Transfer in Metropolitan Sydney

The transfer of the critically ill patient is often complex and difficult, and may contribute to increased morbidity. It is therefore valuable to have an understanding of the practical problems relating to patient transfer, and common management strategies, in order to minimise adverse outcomes.

Key issues in the process of transporting the critically ill patient in metropolitan Sydney include: (i) particular problems and pitfalls during the transfer process; (ii) risk factors in transferring patients and the appropriateness of escorts and transfer procedures; (iii) procedures for arranging a patient transfer; (iv) the role of the NSW Medical Retrieval Co-ordination Centre (MRCC); (v) preparation of the patient for transfer, (vi) education of staff on the concept of safe matching of patient needs to appropriate escorts; and (vii) the need for a co-ordinated patient transfer system to Sydney metropolitan hospitals.

An understanding of these issues, and an appropriate response to them from hospital staff will ensure safe and efficient transportation of critically ill patients in metropolitan Sydney.     

On-demand IC351 (Cialis) enhances erectile function in patients with erectile dysfunction

IC351 (Cialis) is a selective inhibitor of PDE5. The efficacy and safety of on-demand dosing of IC351 in men with erectile dysfunction was assessed in a multicenter, double-blind, placebo-controlled study. One hundred seventy-nine men (mean age: 56 y) were randomized to receive placebo or IC351 at doses of 2, 5, 10 or 25 mg, taken on demand over a 3-week period. The primary endpoints were change from baseline in responses to Questions 3 (Q3) and 4 (Q4) of the International Index of Erectile Function (IIEF). IC351 significantly improved IIEF Q3 scores at all doses vs placebo (P < or =0.003). IC351 also significantly improved IIEF Q4 scores in all but the 2 mg group (P < or =0.0003). No significant changes in laboratory values, ECGs, or blood pressure were observed. The most common adverse events were headache and dyspepsia. The conclusion of this study was that on-demand IC351 at doses up to 25 mg was well tolerated and significantly improved erectile function.     

Alpha 4 beta 1 and alpha 5 beta 1 are differentially expressed during myelopoiesis and mediate the adherence of human CD34+ cells to fibronectin in an activation-dependent way

To study the receptors involved in the interaction between extracellular matrix proteins and hematopoietic progenitor cells, we analyzed the expression of beta 1 integrins on CD34+ bone marrow cells by means of immunoflowcytometry. Alpha 4 beta 1 and alpha 5 beta 1 were expressed, whereas alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 6 beta 1, and alpha v beta 1 were virtually absent. Furthermore, we assessed the alpha 4 and alpha 5 expression on committed myeloid progenitor cells. These colony-forming cells were detected in the alpha 4 dull fraction and the alpha 5 dull fraction. During myeloid differentiation, both in vivo and in vitro, a differential expression of alpha 4 beta 1 and alpha 5 beta 1 was observed. alpha 5 beta 1 was found to be lost at the myelocytic-metamyelocytic stage, before the loss of alpha 4 beta 1, at the band stage. Functional studies showed no binding of erythroid progenitor-depleted, CD34+ bone marrow cells to fibronectin. However, protein kinase C activation strongly induced fibronectin binding (68% of the cells). Inhibition experiments with specific antibodies and peptides showed the binding to be mediated by both alpha 4 beta 1 and alpha 5 beta 1. Also, colony-forming cells of granulocytes and macrophages were demonstrated to adhere to fibronectin in an activation-dependent way. During granulocyte colony-stimulating factor-induced in vitro maturation, the activation-dependent fibronectin binding capacity is gradually lost. We conclude that: (1) CD34+ bone marrow cells express alpha 4 beta 1 and alpha 5 beta 1; (2) the expression of alpha 4 beta 1 and alpha 5 beta 1 is differentially expressed during myeloid differentiation; and (3) binding of CD34+ bone marrow cells to fibronectin is activation dependent.     

Vagal hyperactivity in stress induced gastric ulceration in rats

Indirect evidence suggests that stress ulceration is provoked by vagal hyperactivity. However, direct evidence of hypervagal activity during stress conditions is lacking. Experiments were designed to directly measure vagal activity under different stress conditions in rats. Starvation stress for 48 h did not change the mean amplitude of action potentials, but their frequency was significantly decreased. Restraint stress at 22°C increased vagal activity, both amplitude and frequency, in the first 60 min; these responses were markedly enhanced by cold (4°C) and persisted for at least 2 h. Starvation for 48 h did not induce any gastric mucosal lesions. Restraint alone produced petechiae in the gastric mucosa, but cold restraint induced severe haemorrhagic ulcers. It is concluded that cold restraint stress provokes a prolonged vagal hyperactivity, which is one of the causative factors for gastric ulceration.