Use of independent genome-wide assays to discover HOXA signature in colon and rectal cancers and validate a role in tumorigenesis

e15014

Background: Rectal cancer differs from colon cancer in terms of prognosis. Here we present genome-wide expression analysis of 79 colon and rectal tumors and gene dosage analysis of 34 archival colorectal tumors in paraffin (FFPE). Methods: Expression data were acquired ( http://expo.intgen.org/geo/home.do ) from Affymetrix experiments analyzed with GeneSpring software version 7.3 (Silicon Genetics, CA). Expression data were normalized ’per chip’ normalized to the 50th percentile of all values; and ’per gene’ normalized to the median expression level across all samples. Expression Project for Oncology (expO) samples included colon (n=50) and rectum (n=29). Differentially expressed genes were identified by parametric test for which variances were not assumed equal (Welch ANOVA). Array comparative genomic hybridization (aCGH) were performed separately on an independent set of FFPE colorectal tumors (n=34) by 244 K microarrays for CGH, Agilent Technologies, CA and with platform embedded analyses tools of CGH Analytics software and ADM-1 bioinformatics. Functional assay by knockout of HOXA9 promoter by lentiviral sh-RNAi construct was performed on colon cancer cell lines shown to have increased HOXA9 dosage and expression. Results: The analysis of expO colon and rectal cancers generated 42 genes with significant differential expression, 26 showed an increased expression of > 2 fold in colon versus rectal samples. Transcription factor family HOXA9 was the most highly expressed (3.8 fold) in colon versus rectal cancer. The aCGH data showed a low level gain of the HOXA gene to be the most frequent dosage alteration (38%). Validation by IHC and qRT-PCR showed 80% and 76% concordance, respectively. Functional assay by sh-RNAi in cell lines (compared to vehicle only) showed marked decrease in cellular viability (40 to 60%), marked morphologic change and a significantly increased apoptotic rate. Conclusion: Multiple genome-wide assays have identified HOXA9 as differentially dosed and expressed in colon and rectal tumors. Compelling functional data from sh-RNAi experiments suggests a tumorigenic role for HOXA9 in altered apoptosis.

No significant financial relationships to disclose.

Animal-derived surfactants: where are we? The evidence from randomized, controlled clinical trials

Animal-derived surfactants, as well as synthetic surfactants, have been extensively evaluated in the treatment of respiratory distress syndrome (RDS) in preterm infants. Three commonly available animal-derived surfactants in the United States include beractant (BE), calfactant (CA) and poractant alfa (PA). Multiple comparative studies have been performed using these three surfactants. Prospective as well as retrospective studies comparing BE and CA have shown no significant differences in clinical or economic outcomes. Randomized, controlled clinical trials have shown that treatment with PA is associated with rapid weaning of oxygen and ventilatory pressures, fewer additional doses, cost benefits and survival advantage when compared with BE or CA. Recently, a study using an administrative database that included over 20,000 preterm infants has shown a significant decrease in mortality and cost benefits in favor of PA, when compared with BE or CA. Differences in outcomes between these animal-derived surfactants may be related to a higher amount of phospholipids and plasmalogens in PA. To date, animal-derived surfactants seem to be better than synthetic surfactants during the acute phase of RDS and in decreasing neonatal mortality. Further studies are needed comparing animal-derived surfactants with the newer generation of synthetic surfactants.

Choosing a right surfactant for respiratory distress syndrome treatment

Respiratory distress syndrome (RDS) is the most common cause of respiratory insufficiency in preterm infants, especially those born at <30 weeks of gestation. Continuous positive airway pressure has been used since the 1970s as a primary mode of treatment for RDS. Surfactant therapy became available in the 1980s and has become the standard care for infants with or at risk for RDS. Surfactant therapy has been shown to decrease air leaks, neonatal and infant mortality as well as cost among survivors. Natural surfactants derived from animal sources containing surfactant proteins B (SP-B) and C (SP-C) as well as synthetic surfactants with functional SP-B- or SP-C-like protein mimics have been extensively evaluated in preterm neonates with or at risk for RDS. Evidence from randomized controlled trials indicates that treatment with natural surfactants results in faster weaning of supplemental oxygen and mean airway pressure, decreased duration of mechanical ventilation, and decreased mortality when compared to synthetic surfactants. Furthermore, at the present time, there are no approved synthetic surfactants available for use in preterm infants. Beractant, calfactant and poractant alpha are the three commonly used natural surfactants worldwide. Comparative studies including prospective randomized trials as well as large retrospective studies have shown significant differences in outcome and cost among these three natural surfactants. Of the eight prospective, randomized controlled trials and two retrospective studies involving the natural surfactant preparations, treatment with poractant alpha resulted in a significantly decreased mortality, decreased need for additional doses, faster weaning of oxygen and reduced hospital costs when compared to treatment with beractant or calfactant. These differences in outcome may be due to differences in phospholipid and SP-B content, amount of antioxidant phospholipids, plasmalogens, anti-inflammatory properties and viscosity among these three surfactants. Additional studies of administering surfactant non-invasively via laryngeal mask airway in preterm infants weighing >1,200 g and as an aerosol preparation are currently in progress.

Disposition of loratadine in healthy volunteers

The absorption, metabolism and excretion of carbon-14-labeled loratadine (LOR, SCH 29851, Claritin) administered orally to healthy male volunteers were evaluated. Following a single oral 10-mg dose of [(14)C]LOR ( approximately 102 microCi), concentrations of LOR and desloratadine (DL; a pharmacologically active descarboethoxy metabolite of LOR) were determined in plasma. Metabolites in plasma, urine and feces were characterized using a liquid chromatography-mass spectrometry system (LC-MS) connected in line with a flow scintillation analyzer (FSA). Maximum plasma LOR and DL concentrations were achieved at 1.5 h and 1.6 h, respectively; thus, LOR was rapidly absorbed but also rapidly metabolized as indicated by these similar t(max) values. Metabolite profiles of plasma showed that LOR was extensively metabolized via descarboethoxylation, oxidation and glucuronidation. Major circulating metabolites included 3-hydroxy-desloratadine glucuonide (3-OH-DL-Glu), dihydroxy-DL-glucuronides, and several metabolites resulting from descarboethoxylation and oxidation of the piperidine ring. LOR was completely metabolized by 6 h post-dose. LOR-derived radiocarbon was excreted almost equally in the urine (41%) and feces (43%). About 13% of the dose was eliminated in the urine as 3-OH-DL-Glu. DL accounted for less than 2% of the dose recovered in the urine and only trace amounts of LOR were detected. 3-OH-DL was the major fecal metabolite ( approximately 17% of the dose). The combined amount of 5- and 6-hydroxy-DL contributed to an additional 10.7% of the dose in feces. Approximately 5.4% and 2.7% of the dose were excreted in the feces as unchanged drug and DL, respectively.

Metabolism and excretion of loratadine in male and female mice, rats and monkeys

The metabolism and excretion of loratadine (LOR), a long-acting non-sedating antihistamine, have been evaluated in male and female mice, rats and monkeys. Following a single (8 mg kg-1) oral administration of [14C]LOR, radioactivity was predominantly eliminated in the faeces. Profiling and characterization of metabolites in plasma, bile, urine and faeces from male and female mice, rats and monkeys showed LOR to be extensively metabolized with quantitative species and gender differences in the observed metabolites. In all species investigated, the primary biotransformation of LOR involved decarboethoxylation to form desloratadine (DL), subsequent oxidation (hydroxylation and N-oxidation) and glucuronidation. More than 50 metabolites were profiled using liquid chromatography-mass spectrometry (LC-MS) with in-line flow scintillation analysis (FSA) and characterized using LC-MSn techniques. The major circulating metabolite in male rats is a DL derivative in which the piperidine ring was aromatized and oxidized to pyridine-N-oxide. Much lower levels of the pyridine-N-oxide metabolite were observed in female rat plasma. In contrast, the relative amount of DL was notably higher in female than in male rats. The major circulating metabolite in either gender of mouse and male monkey is a glucuronide conjugate of an aliphatic hydroxylated LOR; in the female monkey, the major circulating metabolite is formed through oxidation of the pyridine moiety and subsequent glucuronidation. Qualitatively similar metabolic profiles were observed in the mouse, rat and monkey urine and bile, and the metabolites characterized resulted from biotransformation of LOR to DL, hydroxylation of DL and subsequent glucuronide conjugation. 5-Hydroxy-desloratadine was the major faecal metabolite across all three species irrespective of gender.

Disposition of desloratadine in healthy volunteers

The absorption, metabolism and excretion of desloratadine (DL, Clarinex) were characterized in six healthy male volunteers. Subjects received a single oral 10-mg dose of [(14)C]DL ( approximately 104 microCi). Blood, urine and feces were collected over 240 h. DL was well absorbed; drug-derived radioactivity was excreted in both urine (41%) and feces (47%). With the exception of a single subject, DL was extensively metabolized; the major biotransformation pathway consisted of hydroxylation at the 3 position of the pyridine ring and subsequent glucuronidation (3-OH-DL-glucuronide or M13). In five of the six subjects, DL was slowly eliminated (mean t((1/2)) = 19.5 h) and persisted in the plasma for 48-120 h post-dose. This is in contrast to a t((1/2)) of approximately 110 h and quantifiable plasma DL concentrations for the entire 240-h sampling period in one subject, who was identified phenotypically as a poor metabolizer of DL. This subject also exhibited correspondingly lower amounts of M13 in urine and 3-OH-DL (M40) in feces. Disposition of DL in this subject was characterized by slow absorption, slow metabolism and prolonged elimination. Further clinical studies confirmed the lack of safety issues associated with polymorphism of DL metabolism (Prenner et al. 2006, Expert Opinion on Drug Safety, 5: 211-223).

Changes in the DP-gram during the preterm and early postnatal period

OBJECTIVES

To describe and define changes in the infant DP-gram during an age continuum from the preterm period through the first 6 mo of postnatal life. This information provides normative guidelines for audiologists or hearing screeners using DPOAEs to monitor infant hearing status.

DESIGN

In this retrospective study, 2f1 - f2 DP-grams (DPOAE level x f2) were recorded with primary tones at 65/55 dB SPL, f2/f1 = 1.2, and f2 frequencies ranging from 1500 to 9000 Hz. Results from one ear of 290 healthy infants ranging in age from 31 wks postconceptional age to 6-mo-old were examined. Data were collected using both longitudinal design (repeated tests on the same infant over time) and cross-sectional methodology (a different group of subjects representing each age category). Subjects were divided into three groups according to age and experimental design. The effects of age and frequency on DPOAE level were analyzed in the three groups separately.

RESULTS

The combined results from the three databases indicate that (1) DPOAE level increased for mid-frequencies throughout the preterm period, from 31 to 33 wks until the time period associated with term birth. This change was significant for 4500 and 6000 Hz; (2) DPOAE level decreased as f2 frequency increased. In many infants, a shallow trough was observed with peak amplitude at 1500 Hz, a reduction in response amplitude through 4500 Hz, and a second peak around 6000 Hz; (3) during the postnatal period from birth through 6 mo, DPOAE level did not change significantly as a function of age and the DP-gram was relatively flat across f2 frequency; and (4) infants showed mean DPOAE levels that were 4 to 12 dB higher than adult levels.

CONCLUSIONS

The results indicate a frequency-dependent increase in DPOAE level during the preterm period in human infants. After birth, there is little change in amplitude through 6 mo. The infant DPOAE remains larger than adult amplitude at all ages tested, as shown in other reports, well into childhood, suggesting continued changes in DPOAE level during the first decade of life. Recent research suggests that immaturities of the conductive pathway may account for infant-adult differences in DPOAE level; however, it is not yet clear whether other sources contribute.

Lung protective ventilatory strategies in very low birth weight infants

Respiratory distress syndrome (RDS) is the most common respiratory diagnosis in preterm infants. Surfactant therapy and mechanical ventilation using conventional or high-frequency ventilation have been the standard of care in the management of RDS. Bronchopulmonary dysplasia (BPD) continues to remain as a major morbidity in very low birth weight infants despite these treatments. There is no significant difference in pulmonary outcome when an optimal lung volume strategy is used with conventional or high-frequency ventilation. Lung injury is directly related to the duration of invasive ventilation via the endotracheal tube. Studies using noninvasive ventilation, such as nasal continuous positive airway pressure and noninvasive positive pressure ventilation, have shown to decrease postextubation failures as well as a trend toward reduced risk of BPD. Lung protective ventilatory strategy may involve noninvasive ventilation as a primary therapy or following surfactant administration in very preterm infants with RDS. Initial steps in the management of preterm infants may also include sustained inflation to establish functional residual capacity, followed by noninvasive ventilation to minimize lung injury and subsequent development of BPD.

Precursors of cardiorespiratory events in infants detected by home memory monitor

In 1,079 infants monitored for >700,000 hr at home for apnea or bradycardia, we found an association between infants having multiple events exceeding conventional or a priori defined more extreme thresholds and less favorable developmental outcome at 1 year of age than infants with few or no events. If it is necessary to prevent such events to minimize risk for developmental morbidity, there is reason to determine whether there are disturbances in advance of the apnea or bradycardia that herald their onset. In the 85 infants with at least 1 extreme event and 1 conventional event, we hypothesized that apnea and bradycardia do not occur de novo but rather are preceded by cardiorespiratory and hemoglobin O2 saturation changes. We compared recorded time intervals preceding these events, and we analyzed three preceding time intervals for each conventional and extreme event, and each non-event recording: Time-2 hr: up to 2 hr before; Time-1 hr: up to 1 hr before; and Time-75 sec: the 75 sec immediately preceding each event. O2 saturation progressively decreased preceding both conventional and extreme events, and progressive increases occurred in heart and breathing rate variability. Duration of respiratory pauses and of periodic breathing progressively increased preceding conventional events, respiratory rate variability increased immediately preceding conventional events and at 1 hr preceding extreme events, and O2 saturation decreased immediately preceding both conventional and extreme events. Thus, conventional and extreme events do not occur de novo but rather are preceded by autonomic instability of the cardiorespiratory system.

Optimal ventilatory strategies and surfactant to protect the preterm lungs

Invasive ventilation via the endotracheal tube is one of the most common therapeutic interventions performed in preterm infants with respiratory failure. Respiratory distress syndrome (RDS) occurs in about 50% of preterm infants born at less than 30 weeks of gestational age. Mechanical ventilation using conventional or high-frequency ventilation and surfactant therapy have become the standard of care in management of preterm infants with RDS. However, bronchopulmonary dysplasia (BPD) remains as a major morbidity with adverse pulmonary and nonpulmonary outcomes in preterm infants despite these interventions. Ventilator-associated lung injury appears to be related to the duration of invasive ventilation via the endotracheal tube rather than the mode of ventilation. Randomized controlled trials comparing conventional mechanical ventilation and high-frequency ventilation, using 'optimal ventilatory strategies', have shown no significant difference in rates of BPD. Use of noninvasive ventilation, such as nasal continuous positive airway pressure and nasal intermittent positive pressure ventilation has shown a significant decrease in postextubation failure as well as reduced incidence of BPD. Optimal ventilatory strategy in preterm infants with RDS may begin in the delivery room with application of sustained inflation to establish functional residual capacity, followed by surfactant therapy and rapid extubation to noninvasive ventilation to decrease the incidence of BPD and improve overall outcome.

Transitional hypothermia in preterm newborns

Hypothermia remains a significant challenge in the initial care of premature infants. Although a number of prevention strategies have been identified, hypothermia is still a common event, especially in extremely low birth weight infants. Using data from four centers, we documented an incidence of hypothermia on admission to the neonatal intensive care unit from the delivery room of 31-78% for infants <1500 g birth weight. Increased efforts will be necessary to prevent early hypothermia in very preterm infants, especially with respect to the environmental conditions of the delivery room itself.

Bariatric surgery improves cardiac function in morbidly obese patients with severe cardiomyopathy

BACKGROUND

Longstanding morbid obesity can be associated with severe cardiomyopathy. However, the safety and efficacy of bariatric surgery in patients with severe cardiomyopathy has not been studied, and the effect of surgical weight loss on postoperative cardiac function is also unknown. In addition, morbidly obese patients have significantly increased mortality associated with cardiac transplantation, often precluding them from becoming recipients.

METHODS

A retrospective study of patients with a left ventricular ejection fraction < or =35% who underwent bariatric surgery (1998-2005) was performed. Short-term morbidity/mortality, length of stay, excess weight loss, pre- and postoperative left ventricular ejection fraction, and New York Heart Association (NYHA) functional class were assessed.

RESULTS

A total of 14 patients (10 men and 4 women) with a mean preoperative body mass index of 50.8 +/- 2.04 kg/m(2) underwent bariatric surgery (10 underwent laparoscopic Roux-en-Y gastric bypass, 1 open Roux-en-Y gastric bypass, 2 sleeve gastrectomy, and 1 laparoscopic gastric banding). The complications were pulmonary edema in 1, hypotension in 1, and transient renal insufficiency in 2. The median length of stay was 3.0 days (range 2-9). The mean excess weight loss at 6 months was 50.4%, with a decrease in the mean body mass index from 50.8 +/- 2.04 kg/m(2) to 36.8 +/- 1.72 kg/m(2). The mean left ventricular ejection fraction at 6 months had significantly improved from 23% +/- 2% to 32% +/- 4% (P = .04), correlating with improved functional capacity, as measured by the NYHA classification. Preoperatively, 2 patients (14%) had an NYHA classification of IV, 6 (43%) a classification of III, and 6 (43%) a classification of II. At 6 months postoperatively, no patient had an NYHA classification of IV, 2 (14%) had a classification of III, and 12 (86%) an NYHA classification of II. Two patients had undergone cardiac transplant evaluations preoperatively and underwent successful transplantation after weight loss.

CONCLUSION

The results of our study have shown that bariatric surgery for patients with cardiomyopathy is feasible and effective. Surgically induced weight loss results in both subjective and objective improvement in cardiac function. In addition, surgical weight loss can provide a bridge to transplantation in patients who were prohibited secondary to their morbid obesity.

Supine Sleeping Position Does Not Cause Clinical Aspiration in Neonates in Hospital Newborn Nurseries

OBJECTIVES

To determine the frequency and severity of clinically significant events of spitting up in normal newborns during the first 24 hours of life and to correlate the events with sleeping position.

DESIGN

Prospective observational study.

SETTING

Children born between August 2003 and October 2004 in newborn nurseries at 2 hospitals.

PARTICIPANTS

Healthy full-term newborns (n=3240) (>or=37 weeks estimated gestational age) during the first 24 hours of life.

OUTCOME MEASURES

Frequency of, and intervention required for, spitting up in supine, side-lying, and prone positions while asleep and awake.

RESULTS

Of the 3240 infants, 96.6% did not spit up during sleep. A total of 142 episodes of spitting up were documented in 111 newborns during sleep. While the newborns were supine and asleep, there were 130 episodes of spitting up. Of these episodes, 55% did not require any intervention, 37% only required brief suctioning with a bulb syringe, 6% required gentle stimulation, and 2% required wall suction. Both nurseries had a policy that newborns should sleep supine; therefore, only 6 newborns were noted to have spitting up episodes while lying on the side, with 66.7% requiring no intervention and 33.3% requiring bulb syringe. No episodes of apnea, cyanosis, documented aspirations, neonatal intensive care unit admissions, or deaths from spitting up were noted.

CONCLUSIONS

We conclude that clinically significant spitting up occurs infrequently in hospital newborn nurseries while the newborns are asleep. Fewer than 4% of newborns spit up while sleeping in the supine position in the first 24 hours of life, and none required significant intervention or experienced serious sequelae.

Constitutive IL-10 expression by lung inflammatory cells and risk for bronchopulmonary dysplasia

Expression of IL-10 is decreased in lungs of preterm infants. We determined the constitutive and lipopolysaccharide (LPS)-induced IL-10 synthesis by lung inflammatory cells from preterm and term infants and examined their relationship to gestational age and/or incidence of bronchopulmonary dysplasia (BPD). A total of 37 infants; preterm neonates at gestational ages of 23-27 wk (group 1); 28-34 wk (group 2), and four full-term infants with meconium aspiration (group 3) were enrolled. One sample of lung inflammatory cells, obtained during postnatal d 1-3, and another during postnatal d 4-7 were cultured in vitro in presence or absence of 100 mug/mL of LPS. Secreted IL-10 was measured by ELISA. A positive relationship was found between gestational age and LPS-induced, but not constitutive IL-10 production within 1-3 d of life; group 1 on d 1-3 had a significant number of IL-10 nonresponders compared with group 2. All term neonates in group 3 had positive LPS-induced IL-10 response. Thus, in utero maturation of IL-10 gene expression is due to acquisition of inducibility. In contrast, constitutive IL-10 production within d 1-3 of life correlated with, and predicted the incidence of BPD in the highly vulnerable very premature infants.

Expression of transforming growth factor beta (TGF-b1) by human preterm lung inflammatory cells

Using a previously published model of human BPD this study examines whether preterm lung inflammatory cells produce transforming growth factor beta 1 (TGF-beta1), a cytokine pivotal in pathogenesis of bronchopulmonary dysplasia (BPD), and whether TGF-beta1 expression is regulated by inflammation. Lung inflammatory cells (neutrophils and macrophages) recovered in the broncho-alveolar (BAL) fluid of premature infants intubated for respiratory distress after birth expressed TGF-b1 mRNA and protein. Total and bioactive TGF-beta1 were abundantly found in the BAL fluid of the same infants. In cell culture stimulation by lipopolysaccharide (LPS) did not result in any further expression of total or bioactive TGF-beta1 by neonatal lung inflammatory cells over constitutive concentrations. In conclusion, lung inflammatory cells from premature infants are a source of TGF-beta1 but LPS does not regulate TGF-b1 production in these cells.

Concurrent use of indomethacin and dexamethasone increases the risk of spontaneous intestinal perforation in very low birth weight neonates

BACKGROUND

Dexamethasone or indomethacin predisposes very low birth weight (VLBW) neonates to spontaneous intestinal perforation (SIP). However, no study has specifically investigated the role of the concurrent use of indomethacin and dexamethasone in SIP.

OBJECTIVE

To test whether the concurrent use of indomethacin and dexamethasone increases the risk of SIP.

METHODS

In this single center, retrospective, 2:1 matched, case-control study, the odds of SIP were assessed using univariate and multivariate logistic regression analysis in < or =14-day old VLBW infants.

RESULTS

Sixteen VLBW infants with SIP were matched to 32 controls by birth weight. After adjusting for clinically relevant variables, patients who received > or =3 doses of indomethacin for ductal closure or intraventricular hemorrhage prophylaxis and > or =3 doses of low-dose dexamethasone (0.3 mg/kg cumulative dose over 3 days) for refractory hypotension during the first postnatal week, were 9.6 times more likely to develop SIP [95% CI 1.22, 75.71].

CONCLUSIONS

The combined use of indomethacin and dexamethasone increases the risk of SIP in VLBW neonates.

A dose-escalating and pharmacologic study of bortezomib in adult cancer patients with impaired renal function

2032

Background: Bortezomib is a highly selective and reversible inhibitor of the proteasome with activity in multiple myeloma and other malignancies. Patients (pts) with renal impairment have been treated in previous trials, but there has not been a systematic investigation into the effects of renal dysfunction on dosing. Study objectives were to characterize the pharmacokinetic (PK) and pharmacodynamic (PD) profile of bortezomib, and to determine the maximum tolerated dose (MTD) in adults with advanced malignancy and renal insufficiency ranging in severity from mild to dialysis dependence. Methods: Fifty-one pts have received intravenous bortezomib at 0.7 mg/m2 up to the approved dose of 1.3 mg/m2 on days 1,4, 8, and 11 every 3 weeks. Pts were stratified by 24-hour creatinine clearance (CrCL) normalized to a body surface area of 1.73 m2 into five cohorts per the table . Doses were escalated in cohorts of three pts in groups B-E. Blood samples were assayed for bortezomib concentration, as well as the PD endpoint of 20S inhibition. Results: Escalation of bortezomib doses to 1.3 mg/m2 was well tolerated in all groups with CrCL ≥ 20 mL/min/1.73 m2. There has been only one instance of dose limiting toxicity (group C at 1.3 mg/m2) which did not prevent successful completion of this cohort. No patients discontinued therapy due to renal deterioration. Doses of 0.7 mg/m2 were tolerable in Group D patients (CrCL< 20 mL/min/1.73 m2 ). Five dialysis pts have been treated; 3 at 0.7 mg/m2, and 2 at 1.0 mg/m2. All tolerated therapy well, and accrual to Groups D and E continues. PK and PD assays are underway and the analysis will be reported in full. Conclusions: This study is the first comprehensive evaluation of bortezomib in pts with various degrees of renal insufficiency including dialysis dependence. Bortezemib at the approved dose of 1.3 mg/m2 on this schedule is well tolerated by pts with CrCL ≥ 20 mL/min/1.73 m2. Results of this trial will allow for dosing recommendations for bortezomib use in pts with renal insufficiency.

[Table: see text]

[Table: see text]

The impact of laparoscopic bariatric workshops on the practice patterns of surgeons

BACKGROUND

This study was designed to evaluate the impact of a 2-day laparoscopic bariatric workshop on the practice patterns of participating surgeons.

METHODS

From October 1998 to June 2002, 18 laparoscopic bariatric workshops were attended by 300 surgeons. Questionnaires were mailed to all participants.

RESULTS

Responses were received from 124 surgeons (41%), among whom were 56 bariatric surgeons (open) (45%), 30 advanced laparoscopic surgeons (24%), and 38 surgeons who performed neither bariatric nor advanced laparoscopic surgery (31%). The questionnaire responses showed that 46 surgeons (37%) currently are performing laparoscopic gastric bypass (LGB), 38 (31%) are performing open gastric bypass, and 39 (32%) are not performing bariatric surgery. Since completion of the course, 46 surgeons have performed 8,893 LGBs (mean, 193 cases/surgeon). Overall, 87 of the surgeons (70%) thought that a limited preceptorship was necessary before performance of LGB, yet only 25% underwent this additional training. According to a poll, the respondents thought that, on the average, 50 cases (range, 10-150 cases) are needed for a claim of proficiency.

CONCLUSION

Laparoscopic bariatric workshops are effective educational tools for surgeons wishing to adopt bariatric surgery. Open bariatric surgeons have the highest rates of adopting laparoscopic techniques and tend to participate in more adjunctive training before performing LGB. There was consensus that the learning curve is steep, and that additional training often is necessary. The authors propose a mechanism for post-residency skill acquisition for advanced laparoscopic surgery.

Surfactant therapy in preterm infants with respiratory distress syndrome and in near-term or term newborns with acute RDS

Many different surfactant preparations derived from animal sources, as well as synthetic surfactants, are available for the treatment of preterm infants with respiratory distress syndrome (RDS). Natural, modified surfactants containing surfactant-associated proteins appear to be more effective than non-protein-containing synthetic surfactants. Comparative trials with poractant alfa at a higher initial dose of 200 mg/kg appear to be associated with rapid weaning of FiO2, less need for additional doses, and decreased mortality in infants <32 weeks gestation when compared with beractant. Early rescue (<30 min of age) surfactant therapy is an effective method to minimize over treatment of some preterm infants who may not develop RDS. Surfactant therapy followed by rapid extubation to nasal ventilation appears to be more beneficial than continued mechanical ventilation. In near-term or term newborns with acute RDS, surfactant therapy has been shown to be 70% effective in improving respiratory failure.

Laparoscopic sleeve gastrectomy as an initial weight-loss procedure for high-risk patients with morbid obesity

BACKGROUND

The surgical treatment of obesity in the high-risk, high-body-mass-index (BMI) (>60) patient remains a challenge. Major morbidity and mortality in these patients can approach 38% and 6%, respectively. In an effort to achieve more favorable outcomes, we have employed a two-stage approach to such high-risk patients. This study evaluates our initial outcomes with this technique.

METHODS

In this study, patients underwent laparoscopic sleeve gastrectomy (LSG) as a first stage during the period January 2002-February 2004. After achieving significant weight loss and reduction in co-morbidities, these patients then proceeded with the second stage, laparoscopic Roux-en-Y gastric bypass (LRYGBP).

RESULTS

During this time, 126 patients underwent LSG (53% female). The mean age was 49.5 +/- 0.9 years, and the mean BMI was 65.3 +/- 0.8 (range 45-91). Operative risk assessment determined that 42% were American Society of Anesthesiologists physical status score (ASA) III and 52% were ASA IV. The mean number of co-morbid conditions per patient was 9.3 +/- 0.3 with a median of 10 (range 3-17). There was one distant mortality and the incidence of major complications was 13%. Mean excess weight after LSG at 1 year was 46%. Thirty-six patients with a mean BMI of 49.1 +/- 1.3 (excess weight loss, EWL, 38%) had the second-stage LRYGBP. The mean number of co-morbidities in this group was 6.4 +/- 0.1 (reduced from 9). The ASA class of the majority of patients had been downstaged at the time of LRYGB. The mean time interval between the first and second stages was 12.6 +/- 0.8 months. The mean and median hospital stays were 3 +/- 1.7 and 2.5 (range 2-7) days, respectively. There were no deaths, and the incidence of major complications was 8%.

CONCLUSION

The staging concept of LSG followed by LRYGBP is a safe and effective surgical approach for high-risk patients seeking bariatric surgery.

Cardiovascular Effects of Low-Dose Dexamethasone in Very Low Birth Weight Neonates with Refractory Hypotension

BACKGROUND

Administration of hydrocortisone and relatively high doses of dexamethasone increase blood pressure in volume- and pressor-resistant hypotensive preterm infants. However, little is known about the temporal relationship of dexamethasone administration and the improvement in blood pressure and the weaning of pressors/inotropes. Furthermore, there are no sufficient data available on whether a smaller dose of dexamethasone would also be effective in treating refractory hypotension.

OBJECTIVE

To study the cardiovascular responses to low-dose dexamethasone in very low birth weight neonates with volume- and pressor-resistant hypotension.

METHODS

Retrospective database review. Twenty-four preterm neonates (gestational age 26 (23-34) weeks; birth weight 801 (457-1,180) g; postnatal age 2 (1-24) days, medians (ranges)) who remained hypotensive despite volume administration and combined dopamine and dobutamine treatment at >or=30 microg/kg/min received dexamethasone 0.1 mg/kg followed by 0.05 mg/kg intravenously every 12 h for 5 additional doses if still on pressors >or=8 microg/kg/min.

RESULTS

Two hours after the first dose of dexamethasone the mean blood pressure increased from 30 +/- 5 to 34 +/- 6 mm Hg (p < 0.001) and remained elevated at 4, 6, 12, and 24 h after treatment was started (p < 0.001). Six hours after the initial dose of dexamethasone the pressor/inotrope requirement decreased from 34 +/- 9 to 24 +/- 13 microg/kg/min (p = 0.001) and continued to decrease at 12 and 24 h (p < 0.001). Urine output also increased significantly during the first 6 h after dexamethasone (p < 0.001).

CONCLUSIONS

Low-dose dexamethasone rapidly increases blood pressure and decreases pressor requirements in very low birth weight neonates with volume- and pressor-resistant hypotension.