Histomorphologic findings on human bone samples six months after bone augmentation of the maxillary sinus with Algipore

Sinus grafting, a popular and standard treatment for maxillary atrophy, uses a variety of grafting materials. In this study, specimens obtained 6 months after sinus grafting with Algipore were evaluated under light microscopy and showed osseoformation, xenograft degradation, and bone ingrowth into particles. Osteoblastic cells were embedded in the intracorpuscular bone matrix, which indicated that xenograft particles are an osseoconductive scaffold and stimulate matrix deposition. Acute inflammatory responses after insertion of Algipore did not occur. Particles were degraded during physiologic bone remodeling, and newly formed bone gradually replaced resorbed biomaterial.

Prostaglandin E(1) is able to increase migration of leukocytes through endothelial cell monolayers

Leukocyte interactions with endothelial cells play an important role during inflammatory processes. Leukocytes pass a monolayer of endothelial cells (ECM) to migrate into the extravascular space. The aim of the current study was to investigate whether prostaglandin E(1) (PGE(1)) influences the process of leukocyte migration. In a prospective controlled study, the influence of prostaglandin E(1) (50-5000 ng/mL) on leukocyte migration through endothelial cell monolayers (n = 7) was investigated. Human umbilical endothelial cells (HUVEC) and/or leukocytes were preincubated with clinically relevant, higher, and lower concentrations of prostaglandin E(1) and the amount of leukocyte migration after 3 h was measured. HUVEC were cultured on microporous membrane filters until achievement of a monolayer for investigation of leukocyte migration. Polymorphonuclear leukocytes (PMNL) were isolated from healthy volunteers and PMNL migration was studied under the influence of PGE(1). In clinically relevant concentrations, PGE(1) was able to increase significantly leukocyte migration through endothelial cell monolayers (205 +/- 7.8%, P < 0.05 compared to control; when treating PMNL alone, migration rate was 120 +/- 9.2% compared to control, ns; only endothelial cell monolayers treated up to 145 +/- 10.2%, P < 0.05 compared to control) showing a dose-dependent effect. In this assay, both cell types (PMNL and ECM) could be treated simultaneously, simulating the clinical situation after an iv administration. In conclusion, PGE(1) is able to increase leukocyte migration through endothelial cell monolayers when both cell types are pretreated. The treatment of either leukocytes or endothelial cell monolayers in the cell coculture showed no significant increase. These findings support the theory that prostaglandins may play a major role during inflammation. Future clinical studies are warranted to confirm this hypothesis.

A comparison of hemodynamic changes during the transition from mechanical ventilation to T-piece, pressure support, and continuous positive airway pressure in canines

The immediate transition from positive pressure mechanical ventilation to spontaneous ventilation may generate significant cardiopulmonary hemodynamic alterations based on the mode of weaning selected, particularly in individuals with preexisting cardiac dysfunction. The purpose of this study was to compare hemodynamic responses associated with the initial transition to 3 modes of ventilator weaning (spontaneous ventilation/T-piece, pressure support [PS], and continuous positive airway pressure [CPAP]). Right ventricular hemodynamic responses were evaluated with a thermodilution pulmonary artery catheter; while left ventricular hemodynamic responses were measured by a transducer-tipped Millar catheter and conductance catheter. Two groups of canines were studied. Group 1: normal biventricular function (n = 10) and group 2: propranolol-induced biventricular failure (n = 10). Dependent variables were measured at baseline on controlled mechanical ventilation (MV) and following the initial transition to each of 3 randomized spontaneous ventilatory conditions: T-piece, PS 5 cmH2O, and CPAP 5 cmH2O. Both groups significantly increased cardiac output in response to T-piece. Right ventricular stroke work was also significantly increased with T-piece and CPAP in both groups of subjects. Left ventricular response depended on baseline ventricular function. Baseline ventricular function influenced hemodynamic response to the immediate transition from mechanical to spontaneous ventilation. There were also differential hemodynamic responses based on the ventilatory mode. Consideration of baseline cardiac function may be an important factor in the selection of an appropriate mode of spontaneous ventilation following controlled MV.

Factors differentiating dropouts from completers in a longitudinal, multicenter clinical trial

BACKGROUND

Subject dropout from a prospective, longitudinal trial can produce biases in the remaining sample that affect study findings and their interpretation, yet little is known about factors contributing to dropout.

OBJECTIVE

To determine characteristics differentiating those who complete from those who drop out of a longitudinal multicenter clinical trial.

METHODS

In this study, 578 parents and other caretakers of infants at risk for cardiopulmonary arrest enrolled in a longitudinal trial investigating the psychosocial impact of cardiopulmonary resuscitation training. In this secondary analysis, the baseline sociodemographic, emotional, psychosocial, and infant characteristics of those who dropped from the trial were compared with those who completed the study.

RESULTS

The study was completed by 60% (n = 347) of the participants. Those most likely to drop out were fathers or other caretakers (vs. mothers) employed outside the home who spoke English (vs. Spanish); were assigned to an experimental group (vs. a control group); had higher levels of depression, hostility, and overall psychosocial distress; and held negative views about health care.

CONCLUSION

Although a few sociodemographic characteristics differentiated dropouts from completers, personal, emotional and psychosocial factors were the predominant predictors of dropouts. Other reputed sources of retention difficulties (e.g., income, education, minority status, lack of social support, or problems with family functioning) did not predict dropout.

Thrombus formation on the balloon of heparin-bonded pulmonary artery catheters: an ultrastructural scanning electron microscope study

OBJECTIVE

To investigate heparin-bonded pulmonary artery catheters with respect to thrombus formation and platelet aggregation at the balloon and the shaft using a scanning electron microscope in critically ill patients.

DESIGN

Prospective study.

SETTINGS

Critical care unit and research laboratories.

PATIENTS

Pulmonary artery catheters were inserted in critically ill patients (n = 10).

INTERVENTIONS

Pulmonary artery catheters were removed after 24, 48, 72, or 120 hrs, and the ultrastructure was investigated in specialized research laboratories.

MEASUREMENTS AND MAIN RESULTS

Balloon and shaft were investigated using a scanning electron microscopic technique. Area of thrombus formation was quantified using image analysis. Heparin release of the catheters was measured. The frequency of balloon inflations was investigated in in vitro experiments by inflating catheters different times (0, 10, 20, and 30 times). Twenty-four hours after catheter insertion, scanning electron microscopic images showed thrombus formation and platelet aggregation at the site of the balloon. Seventy-two hours after catheter insertion, a thrombus started to detach. The areas of thrombus formation did not differ, but thrombus organization changed dramatically 72 and 120 hrs after catheter insertion. The shaft was colonized by single cells only. Cracks of the balloon could be observed after 72 hrs, whereas no cracks could be found in in vitro controls. In vitro, heparin release of the pulmonary artery catheters decreased significantly after 24 hrs.

CONCLUSIONS

Scanning electron microscopic images of heparin-bonded pulmonary artery catheters demonstrate thrombus formation on the balloon 24 hrs after pulmonary artery catheter insertion, increasing dramatically at 72 and 120 hrs. The shaft was colonized by single cells only. The thrombus size is not significantly different during the observation time, but the grade and quality of thrombus formation differ.

Evidence of time-dependent autonomic reinnervation after heart transplantation

BACKGROUND

Confirming the clinical significance of reinnervation is important in understanding and anticipating how heart rate (HR) responses of transplant recipients to physiologic stress differs early and late after transplant from that of normal individuals.

OBJECTIVES

To evaluate the functional significance of cardiac reinnervation early and late after heart transplantation.

METHODS

Handgrip and deep breathing tests, passive 80 degrees head-up tilt, and heart rate (HR) responsiveness of 33 transplant recipients (n = 16 at < 5 months and n = 17 at > 1 year after transplant) were compared with those of 16 age- and sex-matched control participants.

RESULTS

HR responses to handgrip and passive tilt were absent early after transplant. HR acceleration normalized but was blunted late after transplant. These findings are consistent with late (>1 year) sympathetic reinnervation in transplant recipients.

CONCLUSIONS

When caring for transplant recipients, nurses should consider the time elapsed since transplant in evaluating HR responsiveness to common procedures and interventions.

Effect of anticoagulation on blood membrane interactions during hemodialysis

BACKGROUND

Adequate anticoagulation is a precondition to prevent extracorporeal blood clotting and to improve biocompatibility during hemodialysis. In this study, we performed a morphologic analysis by using scanning electron microscopy to compare three modes of anticoagulation-conventional unfractionated heparin (UFH), low molecular weight heparin (LMWH; dalteparin sodium), or sodium citrate during hemodialysis-on membrane-associated coagulation activation.

METHODS

Fifteen patients on regular hemodialysis therapy were investigated. Five patients received UFH, five patients LMWH, and five patients sodium citrate as an anticoagulant during a standardized hemodialysis protocol using a single-use polysulfone capillary dialyzer. Membrane-associated clotting was evaluated using a scanning electron microscope. A dialyzer clotting score was used for quantitative description of coagulation activation on membrane segments.

RESULTS

Using UFH as an anticoagulant revealed the most pronounced cell adhesion and thrombus formation and the highest dialyzer clotting score (11.5 +/- 1.3 of a maximal 20 points). LMWH had a lower dialyzer clotting score than UFH (10.4 +/- 1.2 of 20 points). During the use of sodium citrate, a negligible thrombus formation and the lowest dialyzer clotting score (1.6 +/- 0.6 of 20 points, P < 0.05) were observed.

CONCLUSION

The results of this investigation indicate that using sodium citrate as an anticoagulant during hemodialysis induces a lower activation of coagulation than both conventional and fractionated heparin, which might contribute to an improvement of biocompatibility of hemodialysis extracorporeal circulation.

The role of the critical care nurse in preventing heart failure after acute myocardial infarction

Heart failure is a disabling, progressive, and highly lethal condition. This profile makes it an ideal target for preventative strategies. Critical care nurses caring for cardiac patients must be aware of these strategies so that they can effectively assess patient risk and intervene as an educator and advocate for appropriate treatment.

Amoxycillin/clavulanic acid combinations increase transmigration of leucocytes through endothelial cell monolayers: endothelial cells play a key role

Postoperative inflammation is still viewed as an unresolved problem. During inflammation, leucocytes play a tremendous role and migrate from intravascular spaces into the tissue to attack microorganisms. Different agents, e.g. anaesthetic drugs, are able to influence leucocyte recruitment. Previous studies have investigated the influence of amoxycillin on chemotaxis of leucocytes alone. The aim of our study was to examine the effect of amoxycillin/clavulanic acid (co-amoxiclav) on leucocyte migration through endothelial cell monolayers (ECMs). Human umbilical endothelial cells were cultured on microporous membranes, achieving a monolayer. Polymorphonuclear neutrophil leucocytes (PMNLs) were used in a migration assay. The numbers of untreated PMNLs migrating through untreated ECMs were used as control and set as 100%. PMNLs and/or ECMs were pretreated with co-amoxiclav using clinically relevant as well as higher and lower concentrations. Co-amoxiclav was able to increase PMNL migration through ECMs significantly (P<0.05) when both cell types were treated (291+/-18.7%). When PMNLs or ECMs were treated alone, it could be shown that ECMs were more affected than PMNLs. The greatest effect was shown when both cell types, PMNLs and ECMs, were treated. In conclusion, co-amoxiclav was identified as a potent drug to increase leucocyte transmigration through ECMs. ECMs were also critically involved. Co-amoxiclav also affects endothelial cells.

Effect of cardiopulmonary resuscitation training for parents of high-risk neonates on perceived anxiety, control, and burden

OBJECTIVES

STUDY OBJECTIVES

(1) To compare the effects of 3 methods of cardiopulmonary resuscitation (CPR) training for parents of infants at risk for cardiac or respiratory arrest on anxiety, perception of control, and sense of burden; and (2) to identify parents' attitudes about CPR training and willingness to perform CPR if needed.

METHODS

A longitudinal, controlled trial was conducted with parents and other caretakers of high-risk infants. Subjects were recruited from 5 level III neonatal intensive care units. We enrolled each of 578 subjects in 1 of 4 groups: (1) CPR-Video; (2) CPR-Didactic; (3) CPR-Social Support; or (4) control (no CPR training). Of these, 335 completed the entire study. Data were collected at baseline, and 2 weeks and 6 months after CPR training. The main outcomes measured were perceived anxiety, control, and burden related to caring for a high-risk infant and attitudes about responding to an emergency.

RESULTS

Subjects reported moderately high anxiety, sense of burden, and feelings of loss of control before CPR training. Within groups, subjects in all 3 treatment groups reported improvement in perceptions of anxiety, control, and burden 2 weeks after CPR training, with continued improvement evident 6 months after CPR training (P =.001). In contrast, perceptions were unchanged in the control group. Among groups, at 2 weeks there were significant differences in means between control and CPR-Didactic groups (P =.01), and at 6 months there were significant differences in means between control and CPR-Didactic groups (P =.01) and between control and CPR-Social Support groups (P =.01).

CONCLUSION

CPR training is an important intervention for promoting a sense of control and reducing the anxiety and sense of burden experienced by parents of neonates at risk for cardiopulmonary arrest.

Propofol reduces the migration of human leukocytes through endothelial cell monolayers

OBJECTIVE

To test propofol and the solvent of propofol on leukocyte function in the presence of endothelial cell monolayers. The interactions of leukocytes with endothelial cells play a tremendous role during inflammation. Previous studies have investigated the influence of propofol on leukocytes.

DESIGN

Prospective, controlled study.

SETTING

University research laboratories.

SUBJECTS

Seven independent experiments were performed to investigate the influence of propofol (0.4, 4, and 40 ng/mL) on the migration of human leukocytes through human endothelial cell monolayers. Moreover, the authors tested the solvent of propofol on leukocyte migration.

INTERVENTIONS

Human endothelial cell monolayers and/or human leukocytes were preincubated with clinically relevant higher and lower concentrations of propofol. The amount of leukocyte migration after 3 hrs was measured with a fluorometer.

MEASUREMENTS AND MAIN RESULTS

Human endothelial cells isolated from umbilical veins were cultured on microporous membranes until they formed an endothelial cell monolayer. Leukocytes were separated by standard procedures. The migration of leukocytes through monolayers of endothelial cells using the clinically relevant concentration of propofol was reduced to 93% +- 3.8% (so; p < .05) when the leukocytes but not the endothelial cell monolayers were preincubated with propofol. Leukocyte migration was reduced to 80% - 5.9% (p < .05) when only monolayers of endothelial cells were treated with propofol, and was reduced to 73% + 10.4% (p < .05) when both leukocytes and monolayers of endothelial cells were treated with propofol. The higher and lower concentrations showed a dose-dependent effect. The solvent of propofol had no significant effect.

CONCLUSION

The authors investigated the influence of propofol and its solvent on the interaction between both cell systems-leukocytes and endothelial cells. Propofol is able to reduce significantly the migration of leukocytes through endothelial cell monolayers. The use of different doses revealed a dose-dependent effect. The current model allowed treatment of one cell type: leukocyte or endothelial cell. The results of this investigation indicate that the influence of propofol on leukocyte migration affects endothelial cells more than leukocytes.

Do apnea monitors decrease emotional distress in parents of infants at high risk for cardiopulmonary arrest?

INTRODUCTION

The immediate post-partum period is stressful for most parents. The need to use a home apnea monitor may tax parental coping skills even further. Therefore, we conducted a study to assess the psychosocial consequences of apnea monitoring on parental emotional distress and family functioning.

METHOD

We studied 104 parents of infants at high risk for cardiopulmonary arrest. Fifty-two parents had infants who used home apnea monitors, and 52 parents were age-matched and gender-matched control subjects. Data were collected during the infant's hospitalization, and then at 2 weeks, 3 months, and 6 months after discharge. At 1 year, parents were interviewed about their attitudes toward using the apnea monitor.

RESULTS

Both groups experienced elevated levels of emotional distress, but the group with infants who used the monitors had significant increases in depression and hostility immediately following discharge from the hospital compared with baseline, whereas the non-monitored group had a significant increase in hostility at 6 months. At 1-year follow-up, the majority of the parents reported that they used the monitor every night, felt more secure in using it, and judged it helpful.

DISCUSSION

The immediate period following hospital discharge of infants who need to use a home apnea monitor is characterized by significant emotional distress for the parents, which resolves over time. Anticipatory education and counseling of parents is recommended.

Comparison of psychosocial adjustment of mothers and fathers of high-risk infants in the neonatal intensive care unit

OBJECTIVE

To compare the psychosocial adjustment of mothers and fathers to the birth of a premature or critically ill infant hospitalized in the neonatal intensive care unit (NICU).

STUDY DESIGN

Using a comparative design, we studied 165 mothers and father pairs of high-risk neonates. Mothers were 29.1 +/- 6.7 and fathers were 30.7 +/- 6.8 years old. All infants were hospitalized in the NICU. Couples completed questionnaires in either English or Spanish during the infant's NICU stay.

RESULTS

Mothers were more poorly adjusted and were more anxious, hostile, and depressed than fathers, but both parents experienced levels of emotional distress significantly above normative values. Mothers and fathers reported equal levels of family functioning and social support and shared similar feelings of control related to the health status of their infant.

CONCLUSION

The birth of an infant who requires care in the NICU environment is highly stressful for both parents. Physicians, nurses, and other health professionals working in the NICU should assess the psychosocial adjustment in both parents, but mothers may require more intense education and counseling to reduce the distress they experience.

Stress during mechanical ventilation: benefit of having concrete objective information before cardiac surgery

BACKGROUND

Negative emotional reactions and difficulty in communicating are common in patients receiving mechanical ventilation and may adversely affect recovery from cardiac surgery.

OBJECTIVE

To determine the effect of providing concrete objective information about emotional stress and difficulty in communicating related to mechanical ventilation to Korean cardiac surgery patients.

METHODS

A quasi-experimental 2-group design was used. The 22 subjects in the control group received the usual information; the 21 in the experimental group received concrete objective information in addition to the usual information. State anxiety, negative affect, use of sedative and analgesic medications, and difficulty communicating were compared between the 2 groups after surgery.

RESULTS

Patients who received concrete objective information experienced less anxiety and negative mood during mechanical ventilation, less difficulty in communicating, and a shorter intubation time than did patients in the control group. The 2 groups did not differ in the amount of sedative or analgesic medication used per hour during mechanical ventilation.

CONCLUSIONS

Nursing interventions that include concrete objective information help cardiac patients cope with the stresses associated with surgery and mechanical ventilation.

Stress during mechanical ventilation: benefit of having concrete objective information before cardiac surgery

BACKGROUND: Negative emotional reactions and difficulty in communicating are common in patients receiving mechanical ventilation and may adversely affect recovery from cardiac surgery. OBJECTIVE: To determine the effect of providing concrete objective information about emotional stress and difficulty in communicating related to mechanical ventilation to Korean cardiac surgery patients. METHODS: A quasi-experimental 2-group design was used. The 22 subjects in the control group received the usual information; the 21 in the experimental group received concrete objective information in addition to the usual information. State anxiety, negative affect, use of sedative and analgesic medications, and difficulty communicating were compared between the 2 groups after surgery. RESULTS: Patients who received concrete objective information experienced less anxiety and negative mood during mechanical ventilation, less difficulty in communicating, and a shorter intubation time than did patients in the control group. The 2 groups did not differ in the amount of sedative or analgesic medication used per hour during mechanical ventilation. CONCLUSIONS: Nursing interventions that include concrete objective information help cardiac patients cope with the stresses associated with surgery and mechanical ventilation.

Hydroxyethyl starch reduces the chemotaxis of white cells through endothelial cell monolayers

BACKGROUND

Polymorphonuclear leukocytes (PMNs) play a tremendous role during inflammatory processes. PMNs have to pass a monolayer of endothelial cells to migrate into the extravascular space. Hydroxyethyl starch (HES) is frequently used as a volume expander in critically ill patients.

STUDY DESIGN AND METHODS

The aim of this study was to investigate whether HES influences the chemotaxis of PMNs through endothelial cell monolayers by using a test system that allows the simultaneous treatment of both cell types. Human umbilical endothelial cells were cultured on microporous membrane filters. PMNs were isolated and PMN chemotaxis was studied.

RESULTS

The number of untreated PMNs that migrated through untreated endothelial cell monolayers in response to a chemoattractant was used as a control and set as 100 percent. In clinically relevant concentrations, HES was able to significantly decrease PMN chemotaxis through endothelial cell monolayers, showing a dose-dependent effect (0.1 mg/mL: 99.6 +/- 10.9%, p = NS compared to control; 1 mg/mL: 82.4 +/- 8.3%, p<0.05 compared to control; 10 mg/mL: 62.9 +/- 11.7%, p<0.05). In this assay, both cell types (PMNs and endothelial cells in the monolayer) were treated simultaneously, which simulated the clinical situation after an intravenous injection of HES. The treatment of one cell type, PMNs (89.6 +/- 8.8%, p<0.05) or endothelial cells in the monolayer (76.2 +/- 9.4%, p<0.05), suggests that the influence on endothelial cells is greater.

CONCLUSION

HES is able to significantly reduce the chemotaxis of PMNs through endothelial cell monolayers. The possible clinical consequence of a moderate reduction in endothelium-mediated PMN chemotaxis in critically ill patients remains to be evaluated.

Muscle deoxygenation in aerobic and anaerobic exercise

It has been generally accepted that the use of oxygen is a major contributor of ATP synthesis in endurance exercise but not in short sprints. In anaerobic exercise, muscle energy is thought to be initially supported by the PCr-ATP system followed by glycolysis, not through mitochondrial oxidative phosphorylation. However, in real exercise practice, we do not know how much of this notion is true when an athlete approaches his/her maximal capacity of aerobic and anaerobic exercise, such as during a graded VO2max test. This study investigates the use of oxygen in aerobic and anaerobic exercise by monitoring oxygen concentration of the vastus lateralis muscle at maximum intensity using Near Infra-red Spectroscopy (NIRS). We tested 14 sprinters from the University of Penn track team, whose competitive events are high jump, pole vault, 100 m, 200 m, 400 m, and 800 m. The Wingate anaerobic power test was performed on a cycle ergometer with 10% body weight resistance for 30 seconds. To compare oxygenation during aerobic exercise, a steady-state VO2max test with a cycle ergometer was used with 25 watt increments every 2 min. until exhaustion. Results showed that in the Wingate test, total power reached 774 +/- 86 watt, about 3 times greater than that in the VO2max test (270 +/- 43 watt). In the Wingate test, the deoxygenation reached approximately 80% of the established maximum value, while in the VO2max test resulted in approximately 36% deoxygenation. There was no delay in onset of deoxygenation in the Wingate test, while in the VO2max test, deoxygenation did not occur under low intensity work. The results indicate that oxygen was used from the beginning of sprint test, suggesting that the mitochondrial ATP synthesis was triggered after a surprisingly brief exercise duration. One explanation is that prior warm-up (unloaded exercise) was enough to provide the mitochondrial substrates; ADP and Pi to activate oxidative phosphorylation by the type II a and type I myocytes. In addition, transmural pressure created by the muscle contraction reduces blood flow, causing relative hypoxia.

Meloxicam effect on leukocyte migration under shear stress: a new perfused triple chamber (Hofbauer chamber) assay simulating an in vitro vascular wall

BACKGROUND

Leukocyte migration plays a tremendous role during inflammation. Different drugs are able to influence migration of leukocytes. Several authors have attempted to establish methods for investigation of leukocyte migration. Migration of leukocytes under conditions simulating natural blood flow and shear stress is poorly understood. Moreover, leukocyte migration in the simultaneous presence of endothelial cells and smooth muscle cells (SMC) has not yet been examined thoroughly. The aim of the current study was to create a new three-dimensional assay investigating migration during simulated perfusion. The assay was used for investigating the effect of meloxicam on leukocyte migration under shear stress.

METHODS

Different concentrations of meloxicam (0.09, 0.9, and 9.0 ng/mL) were used in a newly developed triple migration chamber system for investigation of leukocyte migration (n = 7). This new system allows inclusion of SMC-layers. Assay precision tests were done using intra-assay (within-day variability) and interassay (day-to-day variability) controls.

RESULTS

Intra-assay and interassay controls showed reliable results (coefficient of variation: intra-assay 8.53%; interassay 11.39%). Meloxicam in a clinically relevant concentration of 0.9 ng/mL was able to reduce the migration of leukocytes under shear stress (71 +/- 14% SD; P < 0.05), whereas higher and lower concentrations showed a dose dependent effect.

CONCLUSION

This new perfusion system allows investigation of drugs, such as meloxicam, on leukocyte migration under shear stress. Moreover, this assay may be used for studies on other cell-cell interactions, as well as on drug influences.

Leukocyte migration: a new triple migration chamber assay allows investigation of various cell interactions simultaneously

Examination of the interactions between various cells of the vascular wall and blood components are essential for understanding different pathophysiological processes. Such investigations require appropriate techniques. Several groups have attempted to establish different methods. In all blood vessels except capillaries, endothelial cells (EC) and smooth muscle cells (SMC) coexist and interact very closely. The current study describes a new 3-dimensional triple chamber migration assay, studying leukocyte migration through human endothelial cell monolayers (ECM) towards human SMC layers simultaneously. To test the new assay, SMC-layers were prestimulated with different concentrations of tumor necrosis factor alpha (TNF-alpha, 1 ng/ml, 10 ng/ml, 100 ng/ml) over 6 hours. Then, two microporous membranes, a collecting membrane and a third membrane with cultured ECM, were inserted. Freshly isolated peripheral blood mononuclear cells (PBMNC) were seeded on the ECM and transmigrated cells were measured after further 3 hours incubation. The migration against non stimulated SMC-layers was used as control. Prestimulated SMC-layers led to a dose dependent increase of PBMNC migration into the subendothelial cell space. Antibodies against interleukin-1 reduced the PBMNC migration. In conclusion, this assay allows to study cell migration into the subendothelial space and interactions between different vascular cells. Moreover, this assay can also be used for studies on other cell-cell interactions in man.

Sufentanil inhibits migration of human leukocytes through human endothelial cell monolayers

The interactions between blood and vascular wall cells are essential for understanding pathophysiological processes, e.g., during inflammation. The influence of anesthetics on leukocyte function is well documented. An inhibitory effect of thiopental, midazolam, and ketamine on leukocyte chemotaxis in a Boyden chamber chemotaxis assay (i.e., endothelial cells were not included) has been demonstrated. Little is known, however, about the influence of sufentanil on the inflammatory processes. To reach their targets in the tissue in vivo, leukocytes must interact with endothelial cell monolayers (ECMs). The aim of the current study was to investigate the influence of sufentanil on the migration of leukocytes through an ECM. Human umbilical vein endothelial cells were cultured to achieve a monolayer. Isolated polymorphonuclear leukocytes and ECM were preincubated with different concentrations of sufentanil. The rate of leukocyte migration against the chemotactic protein formyl-methyl-leucyl-phenylalanine was measured (n = 7). Sufentanil significantly reduced the amount of leukocyte migration through ECM to 77%+/-7.8% (P < 0.05 compared with control). Endothelial cells as well as leukocytes contributed to this effect: treatment of both cell types showed an additive effect. Although lower concentrations showed no effect, high concentrations reduced leukocyte migration through ECM to 61%+/-7.1%.

IMPLICATIONS

Leukocytes play an important role during inflammation, and anesthetics influence leukocyte functions, e.g., respiratory burst or chemotaxis. The effect of sufentanil on transendothelial leukocyte migration has not been investigated. Therefore, we used a migration assay including endothelial cell monolayers. Sufentanil showed a reducing effect on transendothelial leukocyte migration.

Thiopental inhibits migration of human leukocytes through human endothelial cell monolayers in vitro

OBJECTIVES

The interactions between blood and vascular wall cells are essential for the understanding of pathophysiologic processes, e.g. inflammation. The influence of the anesthetic drug thiopental on leukocyte function is well documented. Recently, an inhibitory effect of thiopental on leukocyte chemotaxis in a Boyden chamber assay (i.e. endothelial cells were not included) was demonstrated. In vivo, leukocytes have to interact with endothelial cell monolayers to invade the tissue. The influence of thiopental on a monolayer of endothelial cells has not yet been investigated. The aim of the current study was to investigate the influence of thiopental on the migration of leukocytes through endothelial cell monolayers (ECM).

MATERIAL AND METHODS

Human umbilical vein endothelial cells (HUVEC) were isolated and cultured on microporous membrane filters to achieve a monolayer. Isolated polymorphonuclear leukocytes (PMNL) as well as ECM were preincubated with different concentrations of thiopental. The rate of leukocyte migration against the chemotactic protein formyl-methyl-leucyl-phenylalanine was measured (n = 7). Thiopental was able to reduce the amount of leukocyte migration through ECM significantly.

CONCLUSION

In conclusion, we could show that thiopental is able to reduce the migration of PMNL through ECM significantly.

Ketamine significantly reduces the migration of leukocytes through endothelial cell monolayers

OBJECTIVE

To study the role of neutrophils in host defense, using human endothelial cells in migration studies in the presence of ketamine (0.3, 3, and 30 microg/mL).

DESIGN

Prospective, controlled study.

SETTING

University research laboratories.

SUBJECTS

Seven independent experiments from different donors were done, investigating the influence of ketamine (0.3, 3, and 30 microg/mL) to the migration of human leukocytes through human endothelial cell monolayers.

INTERVENTIONS

Human endothelial cell monolayers and/or human leukocytes were preincubated with clinically relevant (3 microg/mL), higher (30 microg/mL), and lower (0.3 microg/mL) concentrations of ketamine. The amount of leukocyte migration after 3 hrs was measured in a fluorometer.

MEASUREMENTS AND MAIN RESULTS

Human endothelial cells isolated from umbilical veins were cultured on microporous membranes (polyethylene-terephthalat membranes) until they formed an endothelial cell monolayer. Leukocytes were separated by standard procedures. The migration of leukocytes through monolayers of endothelial cells under the clinically relevant concentration of ketamine was reduced to 59+/-9.8% (SD) (p< .05) when leukocytes but not the endothelial cell monolayers were preincubated with ketamine. Leukocyte migration was reduced to 92+/-7.3% (p > .05) when only monolayers of endothelial cells were treated with ketamine, and to 52+/-8.8% (p< .05) when both leukocytes and monolayers of endothelial cells were treated with ketamine. The higher and lower concentrations showed a dose-dependent effect.

CONCLUSIONS

We investigated the cellular interaction between both cell systems, leukocytes and endothelial cells, simultaneously in the presence of ketamine. Ketamine is able to reduce significantly the migration of leukocytes through endothelial cell monolayers. The use of different dosages revealed a dose-dependent effect. The current model allowed treatment of one cell type, either leukocyte or endothelial cell. Ketamine inhibits the function of leukocytes more than the function of endothelial cells.

Comparison of cardiopulmonary resuscitation training methods for parents of infants at high risk for cardiopulmonary arrest

STUDY OBJECTIVES

To compare three different methods of teaching CPR to parents of infants at high risk for sudden cardiopulmonary arrest and to identify characteristics that predict difficulty in learning CPR.

METHODS

We conducted a prospective, multicenter clinical trial of 480 parents and other infant caretakers. Subjects were randomly assigned to 1 of 3 CPR training protocols: an instructor-taught CPR class, an instructor-taught CPR class followed by a social support intervention, or a self-training video module. CPR proficiency was evaluated with the use of a CPR skills checklist.

RESULTS

Of 480 subjects, 301 (63%) were able to demonstrate successful CPR after training. Univariate analysis revealed that unsuccessful learners were likely to be less educated, to have lower incomes, to never have attended a previous CPR class, and to have better psychosocial adjustment to their infant's illness, compared with successful learners. The proportion of successful learners was significantly higher in the 2 instructor-taught classes than in the self-training video class. Multiple logistic regression analysis was used to develop a predictive profile to describe unsuccessful learners. The following characteristics independently predicted unsuccessful learners: CPR learned in the self-training video group, fewer years of education, and better psychosocial adjustment.

CONCLUSION

Most parents of infants at high risk for sudden death can demonstrate successful CPR skills at the completion of 1 class. However, a significant minority will require extra attention to be successful. Self-training video instruction may not be an adequate substitute for instructor-taught CPR.

Nitric oxide synthase 1 mRNA: tissue-specific variants from rat with alternative first exons

We cloned a novel alternative first exon for nitric oxide synthase 1 (NOS1) that is specific for kidney and two novel alternative second exons which can be inserted between the kidney-specific first exon and the exon currently numbered exon 2. The novel exons were localized within 17 kb upstream of exon 2, and their flanking regions and the boundaries of exon 2 were sequenced. NOS1 mRNAs starting with four additional alternative first exons were characterized with respect to tissue distribution and alternative splicing. Altogether, at least 11 different splice variants were found. Those present in kidney were mainly lacking exon 2.

Pathophysiology of heart failure update: the role of neurohumoral activation in the progression of heart failure

Understanding the pathophysiologic mechanisms responsible for producing heart failure is necessary before effective treatments can be developed that increase survival and improve quality of life. Recent advances in the treatment of heart failure can be traced directly to improved appreciation of the role of neurohumoral activation in the pathophysiology of heart failure. Initially adaptive, neurohumoral activation ultimately results in a series of overadjustments that actively participate in the progression of heart failure. In this article, the role of neurohumoral activation, ventricular remodeling, and various peripheral vascular abnormalities in the pathophysiology of heart failure are explored.