Rate dependent far-field R wave sensing in an atrial tachyarrhythmia therapy device

A case is reported of far-field R wave (FFRW) oversensing resulting in inappropriate atrial tachycardia (AT) detection by a dual chamber pacemaker incorporating atrial autoadjusting sensitivity (AAS). FFRW oversensing occurred during periods of functional atrial undersensing (FAU) with PR interval prolongation. Limitations of the pacemaker's ability to reject FFRWs and programming considerations for addressing this unique behavior are discussed.     

Multicenter randomized trial of the spiral Z-stent compared with the Wallstent for malignant biliary obstruction

BACKGROUND: The industry standard since 1990 for self-expanding biliary metallic stents has been the Wallstent. In 1998 the Spiral Z-stent was released. This randomized trial compared the Z-stent with the Wallstent in the treatment of malignant biliary obstruction. METHODS: Patients with unresectable malignant biliary obstruction distal to the bile duct bifurcation were randomized to receive a 10-mm diameter Wallstent or a 10-mm diameter Z-stent. RESULTS: A total of 145 patients were randomized; 13 were excluded. Sixty-four patients who received a Z-stent and 68 who had a Wallstent are included in the analysis. Tumors responsible for bile duct obstruction were pancreatic cancer (108), cholangiocarcinoma (15), metastatic cancer (6), and papillary cancer (3). Metallic stents were successfully placed in all patients. Seven technical problems were encountered during placement of the Z-stent and 5 with the Wallstent. There were 21 occlusions requiring reintervention (8 Z-stent, 13 Wallstent; p = 0.30). Median time to reintervention was the following: Z-stent, 162 days; Wallstent, 150 days (p = 0.22). A total of 104 patients died of progressive disease or other cause; 7 patients remain alive with patent stents. The overall calculated median patency rates were: Z-stent, 152 days; Wallstent, 154 days (p = 0.90). CONCLUSIONS: The Spiral Z-stent is comparable with the Wallstent in terms of placement, occlusion rates, and overall patency. Occasional early occlusion of both stents suggests tumor characteristics instead of the size of the mesh openings in the stents as important factors.     

Inhibition of p38 mitogen activated protein kinase increases lipopolysaccharide induced inhibition of apoptosis in neutrophils by activating extracellular signal-regulated kinase

BACKGROUND: Prolonged polymorphonuclear neutrophil (PMN) survival has been implicated in tissue injury after sepsis. Previously we reported that lipopolysaccharide (LPS) inhibits PMN apoptosis via the activation of the extracellular signal-regulated kinase (ERK). Conversely, the p38 mitogen activated protein kinase (MAPK) pathway is involved in the spontaneous apoptosis of PMNs. The interaction between these 2 pathways and their ability to regulate apoptosis during sepsis remain largely undefined. We hypothesize that there is interaction between the ERK and p38 pathways during sepsis. METHODS: PMNs were isolated from healthy volunteers by Ficoll gradient centrifugation and red blood cell sedimentation. Cells were then pretreated for 1 hour with the ERK inhibitor (PD98059, 10 micromol/L), p38 inhibitor (SB203580, 1 micromol/L), or vehicle. After treatment with LPS, apoptosis and MAPK activity were correlated. RESULTS: LPS stimulation significantly inhibits PMN apoptosis compared with unstimulated cells. Furthermore, inhibition of ERK significantly abrogates this effect, whereas inhibition of p38 augments LPS induced inhibition of apoptosis. Elk-1 phosphorylation (ERK target) is significantly increased by LPS alone and by inhibition of the p38 pathway during LPS stimulation. This correlates with ERK phosphorylation by Western blot. CONCLUSIONS: These data show that p38 inhibition enhances ERK activity during endotoxemia. Furthermore, these data suggest that cooperation between ERK and p38 MAPK pathways dictates the apoptotic potential of PMNs during inflammatory states.     

Influence of an optimized non-ionic emulsifier blend on properties of oil-in-water emulsions.

Properties of oil-in-water emulsions containing non-ionic emulsifiers were evaluated in relation to nature of the dispersed phase, emulsifier composition and processing parameters. Particle size of mineral oil (hydrocarbons)-in-water emulsions was independent of the HLB of an optimized emulsifier blend, whereas, the particle size of olive oil (triglycerides)-in-water emulsions was the smallest at the optimum HLB of the emulsifier blend. The non-ionic emulsifiers reduced the particle size of mineral oil emulsions more efficiently than that of olive oil emulsions. Contrary to previously published reports, the nature of the dispersed phase, HLB of the emulsifier blend or the initial particle size of emulsions showed no influence on the final particle stability of the emulsions. This difference was attributed to the optimization of the emulsifier blend and processing parameters in the preparation of emulsions.     

A comparison of tubal ring and Madlener's techniques of tubal ligation in postpartum cases

Compares Madlener's traditional technique and a new method of tubal ligation as sterilization procedures on postpartum women. The new tubal ring ligation procedure has been welcomed because of its nonreliance on electrocautery, a procedure which has proved to be unsafe. This study is based on the sterilization and follow-up of 300 postpartum women aged 21 to 40. Follow-up was carried out at day 7, at 6 months and at 1 year (78% of sample). Except for a minor surgical complication in 1 subject of each group, surgery was uneventful, averaging 7.9 and 9.0 minutes for tubal ligation and Madlener's technique, respectively. Postoperative complication, common to this type of surgery and unrelated to comparative aspects of the 2 surgeries were noted. Follow-up showed the commonest complaints to be backache, leukorrhea and general weakness. These symptoms, however, are very common in hospital patients. The incidence of backache, though, was significantly higher in the group of women sterilized by the tubal ring technique as compared with Madlener's. Neither group was significantly different in the incidence of postoperative menstrual irregularities; after 1 year the most common abnormality was excessive or scanty menstrual cycle. Pelvic findings showed a slight increase in the number of cervical erosions and endocervicitis in the tubal ring group as opposed to Madlener's; these findings, though, are only coincidental and have no bearing on the method of sterilization. The study also demonstrates that either method can safely be performed in postpartum women.     

Effect of prolactin on tetracycline binding to human spermatozoa.

The effect of different concentrations of prolactin (0 to 60 ng) on the release of tetracycline from human spermatozoa labeled with 7-3H-tetracycline hydrochloride was studied. Prolactin significantly enhanced the release of bound tetracycline, indicating that prolactin may influence the processes associated with sperm capacitation.