Growth hormone improves clinical status in prepubertal children with cystic fibrosis: results of a randomized controlled trial

OBJECTIVES

We conducted a 1-year randomized controlled trial to test the hypothesis that growth hormone (GH) improves the clinical status of children with cystic fibrosis.

STUDY DESIGN

Nineteen prepubertal children were randomized to control (NonTX, n = 9) or to daily injections of GH (0.3 mg/kg/wk) (GHTX, n = 10) for 1 year. Every 3 months height, weight, and lean tissue mass were measured. Caloric intake, resting energy expenditure, pulmonary function, and respiratory muscle strength were measured every 6 months, as were total number of hospitalizations and courses of outpatient intravenous antibiotics.

RESULTS

The GHTX group had significantly greater height, height velocity (NonTX = 3.8 +/- 1.4 cm/y, GHTX = 8.1 +/- 2.4 cm/y; P =.002), weight, weight velocity (NonTX = 2.1 +/- 0.9 kg/y, GHTX = 4.5 +/- 1.1 kg/y; P =.004), and change in lean tissue mass (NonTX = 2.1 +/- 1.6 kg, GHTX = 4.7 +/- 1.7 kg; P =.01) analyzed by the Student t test. The GHTX group had significant improvement in delta forced vital capacity compared with the year before study, and respiratory muscle strength improved. The number of hospitalizations and outpatient intravenous antibiotic courses significantly decreased in the GHTX group but did not change in the NonTX group. No subject had development of cystic fibrosis-related diabetes.

CONCLUSIONS

Results of the first randomized controlled trial of GH treatment in cystic fibrosis indicate that GH improves growth and clinical status.

Growth hormone decreases protein catabolism in children with cystic fibrosis

Despite aggressive nutritional therapy, low body weight and protein catabolism are common problems in children with cystic fibrosis. Previous studies by our group and others have demonstrated improvement in both height and weight in children with cystic fibrosis who were treated with human recombinant GH, and our group has recently documented improved clinical status and lean tissue mass as well. The purpose of this report is to summarize our findings of the effect of GH on whole body protein kinetics in cystic fibrosis and to relate these findings to changes in TNF-alpha levels. We conducted a 1-yr study of 19 prepubertal children with cystic fibrosis (age 7-12 yr, all <94% of ideal body weight). Ten children were randomly assigned to take daily injections of GH (0.3 mg/kg.wk), and nine were randomly assigned to be controls. Baseline results from the subjects with cystic fibrosis were compared with results obtained from nine age- and gender-matched healthy children. Whole body protein turnover was measured at baseline and every 6 months using the stable isotope [1-(13)C]leucine and mass spectrometric analysis. Leucine rate of appearance, a measure of protein catabolism, was similar in both cystic fibrosis subgroups at baseline and was significantly higher than in the control children without cystic fibrosis. Treatment with GH resulted in a significantly lower leucine rate of appearance, as well as significantly lower leucine oxidation. The rate of protein synthesis, as calculated from these numbers, actually decreased in the cystic fibrosis subgroup. TNF-alpha levels were higher in both cystic fibrosis subgroups than in controls and correlated with leucine rate of appearance. The results of this study suggest that one reason GH improves body weight and lean tissue mass is due to improved whole body protein catabolism and improved efficiency of whole body protein kinetics.

DNA fusion vaccine designed to induce cytotoxic T cell responses against defined peptide motifs: implications for cancer vaccines

DNA vaccination offers a strategy to induce immune attack on cancer cells, but tumor Ags are often weak. Inclusion of a "foreign" protein increases immunogenicity, and we found previously that fusion of the fragment C (FrC) of tetanus toxin to the tumor Ag sequence promotes Ab and CD4(+) responses against B cell tumors. For CTL responses, use of the full two-domain FrC may be less helpful, because known immunogenic MHC class I-binding peptides in the second domain could compete with attached tumor-derived epitopes. Therefore, we removed the second domain, retaining the N-terminal domain, which contains a "universal" helper epitope. We investigated the ability to induce CTL responses of candidate peptides placed at the C terminus of this domain. As test peptides, we repositioned the two known CTL motifs from the second domain to this site. Strong CTL responses to each peptide were induced by the engineered construct, as compared with the native FrC construct. Induced CTLs were able to specifically kill tumor cells transfected with FrC as a surrogate tumor Ag both in vitro and in vivo. Further reduction of the domain to a short helper epitope generated only weak CTL responses against fused peptides, and synthetic peptides mixed with the plasmid containing the first domain were ineffective. The single FrC domain-peptide vaccine design also was able to induce high levels of CTLs against a known epitope from carcinoembryonic Ag. Response to peptide was suppressed if two FrC domains were present, consistent with immunodominance. These principles and designs may have relevance for cancer vaccines delivered via DNA.

Prospective randomized trial of polypropylene mesh compared with nylon darn in inguinal hernia repair

BACKGROUND

The main aim of this study was to evaluate outcome in patients undergoing open inguinal hernia repair with either polypropylene mesh or nylon darn.

METHODS

This was a randomized prospective trial of patients who underwent the procedure with follow-up at 1 week, 6 weeks and 1 year.

RESULTS

One hundred men underwent 105 repairs by consultant surgeons and registrars; there were 54 mesh and 51 nylon repairs. Demographics in both groups were similar at the start of the trial, as were the types of hernia. The pain scores at 24, 48 and 72 h were similar, as was the duration of analgesia requirement. There were no differences in early or late complications. Return to normal activity in each group was also similar, with a mean time of 5 weeks. The recurrence rate in both groups was comparable: 4 per cent after mesh repair and 4 per cent after darn repair at 1-year review.

CONCLUSION

Open inguinal hernia repair with a nylon darn was equivalent to polypropylene mesh with respect to early measures of postoperative outcome and recurrence at 1 year.

Major secondary surgery in blunt trauma patients and perioperative cytokine liberation: determination of the clinical relevance of biochemical markers

BACKGROUND

The aim of this study is to assess the associations between the timing of secondary definitive fracture surgery on inflammatory changes and outcome in the patient with multiple injuries. The study population consists of a series of patients with multiple injuries who were managed using a strategy of primary temporary skeletal stabilization followed by delayed definitive fracture fixation.

METHODS

In a prospective cohort study performed at a Level I trauma center, the patients' injuries and operative details as well as immune markers and clinical outcomes were studied. The patients were split into an early secondary surgery group (group ESS, surgery at days 2-4) and a late secondary surgery group (group LSS, surgery at days 5-8). During the posttraumatic course, inflammatory markers (interleukin [IL]-6, tumor necrosis factor-alpha) were determined on a daily basis. Perioperatively, these markers were additionally evaluated at 30 minutes, 7 hours, and 24 hours after initiation of surgery.

RESULTS

Secondary surgery on days 2 to 4 was associated with a higher incidence of postoperative organ dysfunction (n = 33 [46.5%]) than secondary surgery on days 5 to 8 (n = 9 [15.7%], p = 0.01). A significant association between the combination of initial IL-6 values > 500 pg/dL plus surgery on days 2 to 4 and the development of multiple organ failure (r = 0.96, p < 0.001) occurred. A correlation between the initial IL-6 values > 500 pg/dL and surgery on days 5 to 8 (r = 0.57, p < 0.07) could not be found. IL-6 also demonstrated a predictive value for the development of multiple organ failure: IL-6 > 500 pg/dL in group ESS, r = 0.96, p < 0.001; IL-6 > 500 pg/dL in group LSS, r = 0.57, p < 0.07.

CONCLUSION

According to our data, no distinct clinical advantage in carrying out secondary definitive fracture fixation early could be determined. In contrast, in patients who demonstrated initial IL-6 values above 500 pg/dL, it may be advantageous to delay the interval between primary temporary fracture stabilization and secondary definitive fracture fixation for more than 4 days. In patients with blunt multiple injuries undergoing primary temporary fixation of major fractures, the timing of secondary definitive surgery should be carefully selected, because it may act as a second hit phenomenon and cause a deterioration of the clinical status.

Testing the inhibitory effects of Mascara Life on bacterial growth in mascara

BACKGROUND

Mascara Life is a liquid additive that claims to reconstitute mascara consistency while retarding bacterial and fungal growth in tubes of used mascara. The purpose of this study was to compare the effectiveness of mascara alone versus mascara with the addition of Mascara Life against the growth of Staphylococcus aureus, a common bacterial contaminant responsible for potentially serious ocular infections.

METHOD

To simulate 3 to 6 months of use, 12 new tubes of Maybelline Great Lash mascara were dried for 5 consecutive days with the applicator wands removed. Mascara Life was added to a set of six tubes and an equal amount of saline was added to another set of six tubes. Equal amounts of eugonic broth were added to each tube to provide nutrients for the organisms and to further dilute the mascara. One tube from each set served as a negative control. The ten remaining tubes were inoculated with a standardized suspension of Staphylococcus aureus. Two calibrated samples from each tube were plated onto blood agar at 0, 1, 7, 14, 21, and 28 days after initial inoculation. The number of viable organisms was determined after 24 hours of incubation by the plate-count method.

RESULTS

The concentration of viable bacteria was reduced to zero by day 7, and remained at this level through day 28 in all inoculated tubes. The negative control tubes showed no growth throughout the study.

CONCLUSION

The preservatives in both mascara and mascara with the addition of Mascara Life are effective in retarding growth of Staphylococcus aureus.

Description of the Genetic Analysis Workshop 11 Collaborative Study on the Genetics of Alcoholism

Problem 1 of Genetic Analysis Workshop 11 consists of data from a family study of the genetics of alcoholism and related traits contributed by the six centers making up the National Institute for Alcohol Abuse and Alcoholism sponsored by the Collaborative Study on the Genetics of Alcoholism (COGA). The family data included 1,214 members of 105 pedigrees ascertained for having three or more individuals affected with alcoholism. Data available to workshop participants included clinical phenotypes, personality measures, smoking behavior, event-related potentials, platelet monamine oxidase B activity, and a genome scan of 296 markers.

Biochemical changes after trauma and skeletal surgery of the lower extremity: quantification of the operative burden

OBJECTIVE

To quantify changes in variables of inflammation, coagulation, and fibrinolysis in blunt trauma patients with lower extremity fractures who underwent different types of surgical procedures.

DESIGN

Prospective, cohort study.

SETTING

Level I university trauma center.

PATIENTS

We allocated 83 blunt trauma patients in stable condition and 22 patients eligible for elective hip replacement to four treatment groups.

INTERVENTIONS

In 34 multiply traumatized patients with femoral fracture (group PTFF) and in 28 patients with an isolated femoral fracture (group IFF), primary unreamed intramedullary nailing for stabilization of the femoral shaft fracture was performed. In 22 patients, an elective uncemented total hip arthroplasty (group THA) was inserted for osteoarthritis, and in 21 control patients, an isolated ankle fracture (group AF) was acutely stabilized.

MEASUREMENTS AND MAIN RESULTS

From serially sampled central venous blood, the perioperative concentrations of interleukin (IL)-6, of tumor necrosis factor-alpha, of prothrombin fragments 1 + 2, and of D-dimer cross-linked fibrin degradation products were evaluated. Intramedullary instrumentation for an isolated femur fracture caused a significant perioperative increase in the concentrations of IL-6 (preoperative IL-6, 52 +/- 12 pg/mL; IL-6 30 mins postinsertion, 78 +/- 14 pg/mL; p = .02). This increase was comparable with group THA (preoperative IL-6, 46 +/- 16 pg/mL; IL-6 30 mins postinsertion, 67 +/- 11 pg/mL; p = .03). A positive correlation occurred between both groups (r = .83, p < .0004). Multiple trauma patients demonstrated significantly (p = .0002) higher IL-6 concentrations than all other groups throughout the study period and showed a significant increase after femoral nailing (preoperative IL-6, 570 +/- 21 pg/mL; IL-6 30 mins postinsertion, 690 +/- 24 pg/mL; p = .003), whereas no perioperative change was seen in group AF. The highest IL-6 increases were associated with a longer ventilation time (group PTFF) and a longer period of positive fluid balances (groups PTFF, IFF, THA). The coagulatory variables demonstrated similar perioperative increases in groups IFF and THA, but not in groups PTFF and AF. The IL-6 concentrations and the prothrombin fragments 1 + 2 concentrations correlated between groups THA and IFF at 30 mins and at 1 hr after surgery (r2 = .64, p < .02). In all patients the clinical variables were stable perioperatively.

CONCLUSIONS

Major surgery of the lower extremity causes changes to the inflammatory, fibrinolytic, and coagulatory cascades in patients with stable cardiopulmonary function. The inflammatory response induced by femoral nailing is biochemically comparable to that induced by uncemented total hip arthroplasty. In multiple trauma patients, increases, which occurred in addition to those induced by the initial trauma, were measured. Definitive primary femoral stabilization by intramedullary nailing imposes an additional burden to the patient with blunt trauma. A careful preoperative investigation is required to evaluate whether primary definitive stabilization can be performed safely.

Appraisal of early evaluation of blunt chest trauma: development of a standardized scoring system for initial clinical decision making

BACKGROUND

Current techniques for assessment of chest trauma rely on clinical diagnoses or scoring systems. However, there is no generally accepted standard for early judgement of the severity of these injuries, especially in regards to related complications. This drawback may have a significant impact on the management of skeletal injuries, which are frequently associated with chest trauma. However, no convincing conclusions can be determined until standardization of the degrees of chest trauma is achieved. We investigated the role of early clinical and radiologic assessment techniques on outcome in patients with blunt multiple trauma and thoracic injuries and developed a new scoring system for early evaluation of chest trauma.

METHODS

A retrospective investigation was performed on the basis of 4,571 blunt polytrauma (Injury Severity Score [ISS] > or = 18) patients admitted to our unit. Inclusion criteria were treatment of thoracic injury that required intensive care therapy, initial Glasgow Coma Scale score greater than 8 points, and no local or systemic infection. Patients with thoracic trauma and multiple associated injuries (ISS > or = 18) were included. In all patients, the association between various parameters of the thoracic injuries and subsequent mortality and morbidity was investigated.

RESULTS

A total of 1,495 patients fulfilled the inclusion criteria. Patients' medical records and chest radiographs were reevaluated between May 1, 1998, and June 1, 1999. The association between rib fractures and chest-related death was low (> three ribs unilateral, mortality 17.3%, odds ratio 1.01) unless bilateral involvement was present (> three ribs bilateral, mortality 40.9%, odds ratio 3.43). Injuries to the lung parenchyma, as determined by plain radiography, were associated with chest-related death, especially if the injuries were bilateral or associated with hemopneumothorax (lung contusion unilateral, mortality 25.2%, odds ratio 1.82; lung contusion bilateral + hemopneumothorax, mortality 53.3%, odds ratio 5.1). When plain anteroposterior chest radiographs were used, the diagnostic rate of rib fractures (< or = three ribs) increased slightly, from 77.1% to 97.3% during the first 24 hours of admission. In contrast, pulmonary contusions were often not diagnosed until 24 hours after admission (47.3% at admission, 92.4% at 24 h, p = 0.002). A new composite scoring system (thoracic trauma severity score) was developed that combines several variables: injuries to the chest wall, intrathoracic lesions, injuries involving the pleura, admission PaO2/FIO2 ratio, and patient age. The receiver operating characteristic curve demonstrated an adequate discrimination, as demonstrated by a value of 0.924 for the development set and 0.916 for the validation set. The score was also superior to the ISS (0.881) or the thorax Abbreviated Injury Score (0.693).

CONCLUSION

Radiographically determined injuries to the lung parenchyma have a closer association with adverse outcome than chest-wall injuries but are often not diagnosed until 24 hours after injury. Therefore, clinical decision making, such as about the choice of surgery for long bone fractures, may be flawed if this information is used alone. A new thoracic trauma severity score may serve as an additional tool to improve the accuracy of the prediction of thoracic trauma-related complications.

Stress-activated protein kinase/JNK activation and apoptotic induction by the macrophage P2X7 nucleotide receptor

In human and rodent macrophages, activation of the P2X7 nucleotide receptor stimulates interleukin-1beta processing and release, apoptosis, and killing of intracellular Mycobacterium tuberculosis. Signaling pathways downstream of this ionotropic ATP receptor are poorly understood. Here we describe the rapid activation of the stress-activated protein kinase (SAPK)/JNK pathway in BAC1 murine macrophages stimulated by extracellular ATP. Brief exposure of the cells to ATP (10-30 min) was sufficient to trigger a rapid accumulation of activated SAPK that was then sustained for >120 min. Several observations indicated that the P2X7 receptor mediated this effect. 1) ATP and 3'-O-(4-benzoyl)benzoyl-ATP were the only agonistic nucleotides. 2) The effect was inhibited by oxidized ATP and the isoquinoline KN-62, two known P2X7 receptor antagonists. 3) ATP-induced SAPK activation could be recapitulated in P2X7 receptor-transfected HEK293 cells, but not in wild-type HEK293 cells. Because P2X7 receptor stimulation can rapidly activate caspase family proteases that have been implicated in the induction of the SAPK pathway, we investigated whether ATP-dependent SAPK activation involved such proteases. Brief exposure of BAC1 macrophages to extracellular ATP induced DNA fragmentation, alpha-fodrin breakdown, and elevated levels of caspase-3-type activity. Asp-Glu-Val-Asp-cho, a caspase-3 inhibitor, inhibited ATP-induced DNA fragmentation and alpha-fodrin proteolysis, but had no effect on ATP-induced SAPK activation. Tyr-Val-Ala-Asp-chloromethyl ketone, a caspase-1 inhibitor, prevented ATP-induced release of processed interleukin-1beta, but not ATP-dependent SAPK activity. We conclude that activation of ionotropic P2X7 nucleotide receptors triggers a strong activation of SAPK via a pathway independent of caspase-1- or caspase-3-like proteases.

Continuing Education in Nursing: A 10-Year Retrospective Study of CE Offerings Presented by the Kentucky Nurses Association

BACKGROUND

The purpose of this retrospective study was to evaluate continuing education (CE) offerings presented by the Kentucky Nurses Association during a 10-year period.

METHOD

Data were collected and analyzed from 37 CE offerings (N = 474 respondents).

RESULTS

Findings revealed that the majority of the respondents reported that the CE offerings were useful, stimulated them to seek further information, and resulted in acquisition of significant knowledge or skills for nursing education or practice. However, fewer than half of the respondents reported they were able to implement changes in nursing education or practice as a result of the CE offerings.

CONCLUSION

Findings supported the usefulness of CE in nursing education and practice and the need for further research evaluating CE and the correlation between CE and nursing education and practice.

Hip dislocation in patients with multiple injuries. A followup investigation

The combination of traumatic hip dislocation and multiple trauma have not been well documented in the medical literature to date. The role of surgery therefore has not been well defined in these patients. During a 12-year period, 29 consecutive patients with 31 traumatic hip dislocations with concomitant Injury Severity Scores exceeding 18 points were treated at the authors' institution. An initial satisfactory closed reduction was achieved in 23 patients, two patients had failed reductions, and four patients had noncongruous reductions. Open surgical procedures were done on these patients and on 10 additional patients who had associated acetabular or femoral head fractures. Overall, seven patients from the group died including two patients who had surgical procedures. From 17 living patients who did not require surgery for failed or noncongruous reductions, 13 patients were available for followup at a mean of 8 years after their injury. The clinical results at this followup were excellent in three hips, good in seven hips, and fair in four hips. The radiologic results, however, showed that five patients had early (Grades I and II according to Matta) hip degeneration and seven patients had Grade II (according to Ficat) avascular necrosis of the femoral head. These changes were not clinically significant at this followup and it is proposed that these results justify a policy of active treatment of traumatic hip dislocation in patients with multitrauma.

The development of an ethanol model using social insects I: behavior studies of the honey bee (Apis mellifera L.)

BACKGROUND

The purpose of this experiment was to test the feasibility of creating an animal model of ethanol consumption using social insects. Honey bees were selected as the model social insect because much is known about their natural history, physiology, genetics, and behavior. They are also inexpensive to procure and maintain. Of special interest is their use of communication and social organization.

METHODS

Using both between- and within-experiment designs, studies were conducted with harnessed foragers to determine whether honey bees would consume ethanol mixed with sucrose (and, in some cases, water). Shuttle-box and running-wheel studies were conducted to examine the effect of ethanol on locomotion. The effect of ethanol on stinging behavior in harnessed foragers was investigated. The effect of ethanol on Pavlovian conditioning of proboscis extension was also investigated. Finally, in a self-administration study, foraging honey bees were trained to fly to an artificial flower containing ethanol.

RESULTS

(1) Harnessed honey bees readily consume 1%, 5%, 10%, and 20% ethanol solutions; (2) 95% ethanol will also be consumed as long as the antennae do not make contact with the solution; (3) with the exception of 95% ethanol, consumption as measured by contact time or amount consumed does not differ in animals that consume 1%, 5%, 10%, and 20% ethanol solutions; (4) exposure to a lesser (or greater) concentration of ethanol does not influence consumption of a greater (or lesser) concentration; (5) consumption of 10% and 20% ethanol solutions decreases locomotion when tested in both a shuttle-box and running-wheel situation; (6) consumption of 1%, 5%, 10%, and 20% ethanol does not influence stinging behavior in harnessed foragers; (7) ethanol solutions greater than 5% significantly impair Pavlovian conditioning of proboscis extension; and (8) free-flying honey bee foragers will readily drink from an artificial flower containing 5% ethanol.

CONCLUSIONS

The experiments on consumption, locomotion, and learning suggest that exposure to ethanol influences behavior of honey bees similar to that observed in experiments with analogous vertebrates. The honey bee model presents unique research opportunities regarding the influence of ethanol in the areas of language, social interaction, development, and learning. Although the behavioral results are interesting, similarity between the physiologic effects of ethanol on honey bees and vertebrates has not yet been determined.

Alcoholism susceptibility loci: confirmation studies in a replicate sample and further mapping

BACKGROUND

There is substantial evidence for a significant genetic component to the risk for alcoholism. A previous study reported linkage to chromosomes 1, 2, and 7 in a large data set that consisted of 105 families, each with at least three alcoholic members.

METHODS

Additional genotyping in the 105 families has been completed in the chromosomal regions identified in the initial analyses, and a replication sample of 157 alcoholic families ascertained under identical criteria has been genotyped. Two hierarchical definitions of alcoholism were employed in the linkage analyses: (1) Individuals who met both Feighner and DSM-III-R criteria for alcohol dependence represented a broad definition of disease; and (2) individuals who met ICD-10 criteria for alcoholism were considered affected under a more severe definition of disease.

RESULTS

Genetic analyses of affected sibling pairs supported linkage to chromosome 1 (LOD = 1.6) in the replication data set as well as in a combined analysis of the two samples (LOD = 2.6). Evidence of linkage to chromosome 7 increased in the combined data (LOD = 2.9). The LOD score on chromosome 2 in the initial data set increased after genotyping of additional markers; however, combined analyses of the two data sets resulted in overall lower LOD scores (LOD = 1.8) on chromosome 2. A new finding of linkage to chromosome 3 was identified in the replication data set (LOD = 3.4).

CONCLUSIONS

Analyses of a second large sample of alcoholic families provided further evidence of genetic susceptibility loci on chromosomes 1 and 7. Genetic analyses also have identified susceptibility loci on chromosomes 2 and 3 that may act only in one of the two data sets.

Quantification of facial contamination with blood during orthopaedic procedures

Operative surgery exposes the surgeon to possible blood-borne infections. Risks include pen-etrating injuries and conjunctival contact with infected blood. Visor masks worn during orthopaedic trauma procedures were assessed for blood contamination using computer analysis. This was found to be present on 86% of masks, of which only 15% was recognized by the surgeon intraoperatively. Of the blood splashes 80% were less than 0.6mm in diameter. We conclude that power instrumentation produces a blood particulate mist causing considerable microscopic, facial contamination which is a significant risk to the surgeon.

Transgenic rescue of aganglionosis and piebaldism in lethal spotted mice

Complete colonization of the gut by enteric neural precursors depends on activation of ednrB and Ret receptors by their respective ligands, edn3 and gdnf. Mutations that eliminate expression of either ligand or either receptor produce intestinal aganglionosis in rodents and humans. Embryos homozygous for the lethal spotted (ls) allele, a loss of function mutation in the edn3 gene, have no ganglion cells in their terminal large intestines and are spotted, due to incomplete colonization of the skin by melanocyte precursors. Expression of edn3 in enteric neural precursors of transgenic mice compensates fully for deficient endogenous edn3 in ls/ls embryos. The effects of the edn3 transgene are dose-dependent, as lower levels of expression in one line prevent aganglionosis in only a subset of animals and reduce, but fail to eliminate, piebaldism. In contrast, expression of neither constitutively active Ret nor activated ras in enteric neural progenitors alters the severity of aganglionosis or piebaldism in ls/ls mice. Given the spatial and temporal pattern of edn3-transgene expression, our results suggest that edn3/ednrB signals are not required prior to the arrival of crest cells in the gut and endrB stimulation elicits distinct cellular responses from Ret or ras activation. Dev Dyn 2000;217:120-132.

The effect of the position of the limb on venous impulse foot pumps

Compression foot pumps are widely used for the prevention of postoperative venous thrombosis. We tested the efficiency of the pump in ten healthy subjects; the velocity of venous blood flow in the common femoral vein was measured in the horizontal, Trendelenberg (foot-up) and reverse-Trendelenberg (foot-down) positions. Application of the foot pump produced an increase in the venous velocity in all subjects. The mean increase in the horizontal position was 27.2% and in the Trendelenberg position 15.4%. In the reverse-Trendelenberg position, the foot pump produced a mean increase of 102.8%. The efficiency of the compression foot pump in increasing venous return is improved by adopting the reverse-Trendelenberg position. This may increase its thromboprophylactic effect.

The effect of the position of the limb on venous impulse foot pumps

Compression foot pumps are widely used for the prevention of postoperative venous thrombosis. We tested the efficiency of the pump in ten healthy subjects; the velocity of venous blood flow in the common femoral vein was measured in the horizontal, Trendelenberg (foot-up) and reverse-Trendelenberg (foot-down) positions.

Application of the foot pump produced an increase in the venous velocity in all subjects. The mean increase in the horizontal position was 27.2% and in the Trendelenberg position 15.4%. In the reverse-Trendelenberg position, the foot pump produced a mean increase of 102.8%.

The efficiency of the compression foot pump in increasing venous return is improved by adopting the reverse-Trendelenberg position. This may increase its thromboprophylactic effect.

Effect of residual acrylamide monomer from two-dimensional gels on matrix-assisted laser desorption/ionization peptide mass mapping experiments

Residual acrylamide can cause severe suppression of signal intensity during matrix-assisted laser desorption/ionization (MALDI) peptide mass mapping experiments. This suppression phenomenon can compromise the ability to detect low picomole and subpicomolar amounts of peptides extracted from two-dimensional gels. A rapid and simple method that exploits the use of pipette tips incorporating C18 packing materials for the enhancement of MALDI signal intensity is presented. The utility of the method is demonstrated with peptide solutions incorporating residual acrylamide and/or gel monomer components.

Transgenic rescue of aganglionosis and piebaldism in lethal spotted mice

Complete colonization of the gut by enteric neural precursors depends on activation of ednrB and Ret receptors by their respective ligands, edn3 and gdnf. Mutations that eliminate expression of either ligand or either receptor produce intestinal aganglionosis in rodents and humans. Embryos homozygous for the lethal spotted (ls) allele, a loss of function mutation in the edn3 gene, have no ganglion cells in their terminal large intestines and are spotted, due to incomplete colonization of the skin by melanocyte precursors. Expression of edn3 in enteric neural precursors of transgenic mice compensates fully for deficient endogenous edn3 in ls/ls embryos. The effects of the edn3 transgene are dose-dependent, as lower levels of expression in one line prevent aganglionosis in only a subset of animals and reduce, but fail to eliminate, piebaldism. In contrast, expression of neither constitutively active Ret nor activated ras in enteric neural progenitors alters the severity of aganglionosis or piebaldism in ls/ls mice. Given the spatial and temporal pattern of edn3-transgene expression, our results suggest that edn3/ednrB signals are not required prior to the arrival of crest cells in the gut and endrB stimulation elicits distinct cellular responses from Ret or ras activation. Dev Dyn 2000;217:120-132.