DNA Methylation-Based Epigenetic Repression of SLC22A4 Promotes Resistance to Cytarabine in Acute Myeloid Leukemia

Reduced expression of the uptake transporter, OCTN1 (SLC22A4), has been reported as a strong predictor of poor event-free and overall survival in multiple cohorts of patients with acute myeloid leukemia (AML) receiving the cytidine nucleoside analog, cytarabine (Ara-C). To further understand the mechanistic basis of interindividual variability in the functional expression of OCTN1 in AML, we hypothesized a mechanistic connection to DNA methylation-based epigenetic repression of SLC22A4. We found increased basal SLC22A4 methylation was associated with decreased Ara-C uptake in AML cell lines. Pre-treatment with hypomethylating agents, 5-azacytidine, or decitabine, restored SLC22A4 mRNA expression, increased cellular uptake of Ara-C, and was associated with increased cellular sensitivity to Ara-C compared with vehicle-treated cells. Additionally, lower SLC22A4 methylation status was associated with distinct clinical advantages in both adult and pediatric patients with AML. These findings suggest a regulatory mechanism is involved in the interindividual variability in response to Ara-C, and provides a basis for the integration of hypomethylating agents into Ara-C-based treatment regimens.

Solute Carrier Transportome in Chemotherapy-Induced Adverse Drug Reactions

Members of the solute carrier (SLC) family of transporters are responsible for the cellular influx of a broad range of endogenous compounds and xenobiotics. These proteins are highly expressed in the gastrointestinal tract and eliminating organs such as the liver and kidney, and are considered to be of particular importance in governing drug absorption and elimination. Many of the same transporters are also expressed in a wide variety of organs targeted by clinically important anticancer drugs, directly affect cellular sensitivity to these agents, and indirectly influence treatment-related side effects. Furthermore, targeted intervention strategies involving the use of transport inhibitors have been recently developed, and have provided promising lead candidates for combinatorial therapies associated with decreased toxicity. Gaining a better understanding of the complex interplay between transporter-mediated on-target and off-target drug disposition will help guide the further development of these novel treatment strategies to prevent drug accumulation in toxicity-associated organs, and improve the safety of currently available treatment modalities. In this report, we provide an update on this rapidly emerging field with particular emphasis on anticancer drugs belonging to the classes of taxanes, platinum derivatives, nucleoside analogs, and anthracyclines.

Role of equilibrative nucleoside transporter 1 (ENT1) in the disposition of cytarabine in mice

Cytarabine (Ara-C) is a nucleoside analog used in the treatment of acute myeloid leukemia (AML). Despite the many years of clinical use, the identity of the transporter(s) involved in the disposition of Ara-C remains poorly studied. Previous work demonstrated that concurrent administration of Ara-C with nitrobenzylmercaptopurine ribonucleoside (NBMPR) causes an increase in Ara-C plasma levels, suggesting involvement of one or more nucleoside transporters. Here, we confirmed the presence of an NMBPR-mediated interaction with Ara-C resulting in a 2.5-fold increased exposure. The interaction was unrelated to altered blood cell distribution, and subsequent studies indicated that the disposition of Ara-C was unaffected in mice with a deficiency of postulated candidate transporters, including ENT1, OCTN1, OATP1B2, and MATE1. These studies indicate the involvement of an unknown NBMPR-sensitive Ara-C transporter that impacts the pharmacokinetic properties of this clinically important agent.

Interaction Between Sex and Organic Anion-Transporting Polypeptide 1b2 on the Pharmacokinetics of Regorafenib and Its Metabolites Regorafenib-N-Oxide and Regorafenib-Glucuronide in Mice

Regorafenib, a multikinase inhibitor used in the treatment of various solid tumors, undergoes extensive uridine 5′‐diphosphate glucuronosyltransferase (Ugt)1a9‐mediated glucuronidation to form regorafenib‐N‐β‐glucuronide (M7; RG), but the contribution of hepatic uptake transporters, such as organic anion‐transporting polypeptide (Oatp)1b2, to the pharmacokinetics of regorafenib remains poorly understood. Using NONMEM‐based, population‐based, parent‐metabolite modeling, we found that Oatp1b2 and sex strongly impact the systemic exposure to RG in mice receiving oral regorafenib. Metabolic studies revealed that the liver microsomal expression of cytochrome P450 (Cyp)3a11 is twofold lower in female mice, whereas Ugt1a9 levels and function are not sex dependent. This finding is consistent with the metabolism of regorafenib occurring via two competing pathways, and the lack of Oatp1b2 results in decreased clearance of RG. The described model provides mechanistic insights into the in vivo disposition of regorafenib.

Key ^{19}Ne States Identified Affecting γ-Ray Emission from ^{18}F in Novae

Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the β^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified. We report the first measurement of the ^{19}F(^{3}He,tγ)^{19}Ne reaction, in which the placement of two long-sought 3/2^{+} levels is suggested via triton-γ-γ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of 1.5-17 at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.

Murine Pharmacokinetic Studies

Murine pharmacokinetics (PK) represents the absorption, distribution, metabolism, and elimination of drugs from the body, which helps to guide clinical studies, ultimately resulting in more effective drug treatment. The purpose of this protocol is to describe a serial bleeding protocol, obtaining blood samples at six time points from single mouse to yield a complete PK profile. This protocol has proved to be rapid, highly repeatable, and relatively easy to acquire. Comparing with the conventional PK studies, this method not only dramatically reduces animal usage, but also decreases sample variation obtained from different animals.

A non-destructive sampling protocol for field studies of seed dispersal by fishes

This paper presents a standardized protocol for the non-lethal capture of fishes, sampling of stomach contents and quantification of seed dispersal efficiency by frugivorous fishes. Neotropical pacu Piaractus mesopotamicus individuals were collected with fruit-baited hooks. The diets of 110 fish were sampled using a lavage method, which retrieved >90% of stomach contents of both juveniles and adults and allowed individuals to recover within 5 min of treatment. The proportional volume of six food categories was similar for stomachs and whole digestive tracts retrieved by dissection. Fruit pulp was proportionally lower in the stomach. The abundance and species richness of intact seeds increased with fish size independent of whether only stomachs or whole digestive tracts were analysed. The analysis of stomach contents accounted for 62·5% of the total species richness of seeds dispersed by P. mesopotamicus and 96% of common seeds (seed species retrieved from more than one fish). Germination trials revealed that seed viability was similar for seeds collected from the stomach via lavage and seeds that passed through the entire digestive tract. Therefore, stomach contents provide an unbiased representation of the dietary patterns and seed dispersal of frugivorous fishes.

Effects of pneumoperitoneum on intraoperative pulmonary mechanics and gas exchange during laparoscopic gastric bypass

BACKGROUND

Hypercarbia and elevated intraabdominal pressure resulting from carbon dioxide (CO2) pneumoperitoneum can adversely affect respiratory mechanics. This study examined the changes in mechanical ventilation, CO2 homeostasis, and pulmonary gas exchange in morbidly obese patients undergoing a laparoscopic or open gastric bypass (GBP) procedure.

METHODS

In this study, 58 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly allocated to laparoscopic ( n = 31) or open ( n = 27) GBP. Minute ventilation was adjusted to maintain a low normal arterial partial pressure of CO2 (PaCO2), low normal end-tidal partial pressure of CO2 (ETCO2), and low airway pressure. Respiratory compliance, ETCO2, peak inspiratory pressure (PIP), total exhaled CO2 per minute (VCO2), and pulse oximetry (SO2) were measured at 30-min intervals. The acid-base balance was determined by arterial blood gas analysis at 1-h intervals. The pulmonary gas exchange was evaluated by calculation of the alveolar dead space-to-tidal volume ratio (V(Dalv)/V(T)) and alveolar-arterial oxygen gradient (PAO2-PaO2).

RESULTS

The two groups were similar in age, gender, and BMI. As compared with open GBP, laparoscopic GBP resulted in higher ETCO2, PIP, and VCO2, and a lower respiratory compliance. Arterial blood gas analysis demonstrated higher PaCO2 and lower pH during laparoscopic GBP than during open GBP ( p < 0.05). The V(Dalv)/V(T) ratio and PAO2-PaO2 gradient did not change significantly during laparoscopic GBP. Intraoperative oxygen desaturation (SO2 < 90%) did not develop in any of the patients in either group.

CONCLUSIONS

Laparoscopic GBP alters intraoperative pulmonary mechanics and acid-base balance but does not significantly affect pulmonary oxygen exchange. Changes in pulmonary mechanics are well tolerated in morbidly obese patients when proper ventilator adjustments are maintained.

Multiinstitutional experience with the management of superior mesenteric artery injuries

BACKGROUND

Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullen's classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America.

DESIGN

We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality.

RESULTS

There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullen's zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullen's ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullen's zone I or II, and multisystem organ failure.

CONCLUSION

SMA injuries are highly lethal. Fullen's anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullen's zones I and II, Fullen's maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.

Practical utility of the D-dimer assay for excluding thromboembolism in severely injured trauma patients

BACKGROUND

We have advocated the use of a D-dimer assay to exclude the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in surgical and trauma patients suspected of having these diagnoses. Injury is known to increase D-dimer levels independent of thromboembolism. The purpose of this study was to assess the period after injury over which the D-dimer assay remains positive because of injury exclusive of thromboembolism.

METHODS

We prospectively sampled the plasma of severely injured patients for D-dimer using an enzyme-linked immunosorbent assay method at admission; at hours 8, 16, 24, and 48; and at days 3, 4, 5, and 6. Patients were then screened for DVT with a routine duplex Doppler at day 7. Patients were followed for PE, adult respiratory distress syndrome, and disseminated intravascular coagulation.

RESULTS

One hundred fifty-four patients (mean Injury Severity Score of 23) underwent a total of 1,230 D-dimer assays. Twenty-six (17%) had thromboembolism. Nine (6%) patients developed DVT, 2 (1%) developed PE, 13 (8%) developed disseminated intravascular coagulation, and 11 (7%) developed severe adult respiratory distress syndrome. None of the trauma patients with thromboembolism had a (false) negative D-dimer at or after the time of their thromboembolic complication. True-negative D-dimer results as a function of time from injury are: 0 hours, 18%; 8 hours, 16%; 16 hours, 17%; 24 hours, 22%; 48 hours, 37%; day 3, 34%; day 4, 32%; day 5, 30%; and day 6, 30%. The negative predictive value of the assay was 100%. D-dimer levels were significantly higher in those who developed a thromboembolic complication than in those who did not (independent of Injury Severity Score).

CONCLUSION

These data serve to validate D-dimer as a means of excluding thromboembolism, specifically in patients with severe injury (100% negative predictive value). Before 48 hours after injury, however, the vast majority of these patients without thromboembolism had positive D-dimer assays. Because of the high false-positive rate early after severe injury, the D-dimer assay may be of little value before postinjury hour 48.

Evaluation of intra-abdominal pressure after laparoscopic and open gastric bypass

BACKGROUND

Increased intra-abdominal pressure (IAP) postoperatively can adversely affect cardiovascular, pulmonary, and renal function. In this prospective, randomized trial, we compared the IAP in morbidly obese patients after laparoscopic and open gastric bypass (GBP) surgery.

METHODS

64 patients with a body mass index of 40 to 60 kg/m2 were randomized to undergo laparoscopic or open GBP. IAPs were obtained at baseline (after induction of anesthesia), immediately after the operation, and on post-operative day (POD) 1, 2, and 3. Intraoperative and postoperative fluid requirements, urine output, and creatinine clearance were recorded.

RESULTS

Demographics of the two groups were similar. IAP increased from baseline immediately after laparoscopic and open GBP (p < 0.05). IAP returned to baseline by POD 2 after laparoscopic GBP but remained elevated through POD 3 after open GBP. In fact, IAP was lower after laparoscopic GBP than after open GBP on POD 1, 2 and 3 (p < 0.05). The amount of intraoperative IV fluid was similar between groups, but laparoscopic GBP required less IV fluid and facilitated higher urine output postoperatively than open GBP. There was no significant difference in creatinine clearance between groups.

CONCLUSIONS

Laparoscopic GBP resulted in significantly lower IAP, less postoperative fluid required, and greater postoperative urine output than open GBP.

Surgical treatment of atrial fibrillation using radiofrequency energy

BACKGROUND

The Maze III procedure for atrial fibrillation (AF) is effective but has not been used widely due to its complexity, bleeding risk, and added operative time. Surgical radiofrequency ablation may simplify the procedure and make intraoperative correction of AF more accessible and widely performed.

METHODS

Endocardial pulmonary venous isolation was performed on 48 patients with AF undergoing concurrent operation using temperature-controlled radiofrequency energy delivered through a hand-held flexible probe. Additional right-sided lesions were made at the surgeon's discretion.

RESULTS

Forty-two patients were appropriate for analysis (6 died). These patients had an AF duration of 4.8 +/- 6.4 years. At a mean follow-up of 138 +/- 96 days, 34 patients were in sinus rhythm. We were unable to demonstrate a difference in outcome based on AF duration, left atrial size, or addition of right-sided lesions.

CONCLUSIONS

Radiofrequency atrial ablation was effective in 81% of patients with AF at restoring sinus rhythm at an average follow-up of 4 months. This procedure is simple to perform and should broaden the number of patients that receive an AF treatment procedure during concurrent cardiac operation.

Pathologic femoral shaft fractures comparing fixation techniques using cement

To determine the most stable mode of internal fixation for the pathologic femoral shaft fracture with extensive cortical destruction, 2 fixation techniques incorporating methylmethacrylate were compared. Osteotomies through standardized cortical defects were created in intact embalmed femora to simulate a standard pathologic fracture. Fixation obtained with either intramedullary Schneider rods or 28-hold ASIF plates, both using bone cement, was compared in torsion and bending. In torsion, plate-fixed femora failed at a mean load of 71.2 newton-meters compared to 26.8 newton-meters for the Schneider rod counterparts. In bending, plate-fixed bones at a mean load of 8133.9 newtons compared to 1921.4 newtons for rod-fixed femora. Fixation with double plates and methylmethacrylate was clearly more stable and allowed for immediate pain-free ambulation.

Injury surveillance in construction: injuries to laborers

Construction is one of the largest industries in the United States, employing over 7.5 million people. It accounts for 3 times as many accidents as might be expected on a per capita basis. Laborers represent one of 15 job classifications participating in this industry. They have a higher risk of death or injury from a number of causes than do other construction workers.

Whole blood D-dimer assay: an effective noninvasive method to rule out pulmonary embolism

BACKGROUND

The whole blood D-dimer assay has gained recognition as a noninvasive test to rule out pulmonary embolism (PE) in medical patients.

METHODS

We performed a whole blood D-dimer assay in medical and surgical patients undergoing either pulmonary angiogram or pulmonary ventilation perfusion scan for suspected PE or duplex Doppler or venogram for suspected deep venous thrombosis (DVT).

RESULTS

A total of 483 patients were enrolled; 16 were excluded because of an equivocal pulmonary ventilation perfusion scan. The 467 remaining patients had a mean age of 56 +/- 27 years. There were 258 women and 209 men. A total of 353 patients were admitted to a medical service and 114 to surgery/ trauma. A total of 82 patients (18%) developed thromboembolism: 20 had PE, and 62 had DVT.

CONCLUSION

No surgical patient with PE or DVT (n = 27) had a negative D-dimer. A negative D-dimer result in a stable surgical patient should be considered conclusive evidence to rule out thromboembolism and, thus, negate the need for further diagnostic studies. In our surgical patients suspected of DVT or PE, had D-dimer been used, one third of the patients would have avoided an expensive or invasive diagnostic test.

Injury and employment patterns among Hispanic construction workers

This article describes non-fatal injuries among Hispanic construction workers treated at an emergency department from 1990 to 1998. Medical and interview data were analyzed to evaluate and explain the workers' apparently inflated risk of injury. The majority of the injured Hispanic workers were employed in the less-skilled trades. Compared with other injured workers, Hispanics had a higher proportion of serious injuries and were disadvantaged in terms of training and union status. With the exception of union status, these differences largely disappeared after controlling for trade. The physical, financial, and emotional consequences were more apparent 1 year later for injured Hispanics, even after controlling for trade. These observations suggest that minority status is a predictor of trade and that trade is a predictor of injury risk. In addition to reducing injury hazards, interventions should address the limited employment and union membership options that are available to minority workers in the construction industry.

Radical-based asymmetric synthesis: an iterative approach to 1, 3, 5, ... (2n + 1) polyols

[formula: see text] A conceptually novel approach to 1, 3, 5, ... (2n + 1) polyols based on iterative stereo-controlled homologation of chiral hydroxyalkyl radicals is reported. Starting from alpha-keto ester precursors, the general sequence of (1) ketone reduction, (2) auxiliary attachment, (3) saponification, (4) Barton esterification, and (5) radical addition provided the two-carbon homologue in 70-80% overall yield. The simplicity and generality of this iterative strategy for 1, 3, 5, ... (2n + 1) polyol synthesis suggests an attractive alternative for the preparation of molecules containing this structural motif.

Increased use of prophylactic vena cava filters in trauma patients failed to decrease overall incidence of pulmonary embolism

BACKGROUND

Recent studies have reported that placement of vena cava filters (VCFs) early after injury may decrease the incidence of pulmonary embolism (PE) in high-risk trauma patients.

STUDY DESIGN

This was a retrospective review of all trauma patients with placement of VCFs admitted to a single level-1 trauma center between 1989 and 1997. Two cohorts corresponding to years of high or low prophylactic VCF use (PVCF) were compared.

RESULTS

Records were reviewed for 299 trauma patients identified as having had placement of a VCE Two hundred forty-eight filters were placed before the diagnosis of PE. During years of low PVCF use, the overall PE incidence was 0.31%; during years of high PVCF use, the incidence of PE was higher at 0.48% (p = 0.045, chi-square).

CONCLUSIONS

Increased use of PVCFs failed to decrease the overall rate of PE in our trauma patient population.

Bedside noninvasive detection of acute pulmonary embolism in critically ill surgical patients

HYPOTHESIS

We hypothesized that late pulmonary dead space fraction (Fd(late)) would be a useful tool to screen for pulmonary embolism (PE) in a group of surgical patients, including patients who required mechanical ventilation and patients with adult respiratory distress syndrome.

DESIGN

We prospectively calculated Fd(late) in patients with suspected PE who underwent pulmonary angiography.

SETTING

University-based, level I trauma center.

MAIN OUTCOME MEASURE

Ability of Fd(late) to identify patients with PE.

RESULTS

Twelve patients had 14 angiograms for suspected PE. The Fd(late) was 0.12 or above in all 5 patients who had PE; 4 required mechanical ventilation. The Fd(late) values were below 0.12 in 8 of 9 patients without PE. Four patients had adult respiratory distress syndrome. The Fd(late) had 100% sensitivity and 89% specificity for the detection of PE.

CONCLUSIONS

The Fd(late) is a valuable tool for bedside screening of PE in surgical patients. We were able to accurately detect all PEs.

Field triage of the pulseless trauma patient

HYPOTHESIS

Trauma patients who are pulseless at the scene of injury and whose electrical cardiac activity is less than 40 beats/min cannot be revived.

DESIGN

Retrospective review.

SETTING

University hospital, level I trauma center.

PATIENTS

Pulseless trauma patients who had cardiopulmonary resuscitation at the scene, en route, or in the emergency department and presented between January 1, 1991, and July 1, 1996.

MAIN OUTCOME MEASURE

Survival after traumatic cardiopulmonary arrest.

RESULTS

Sixteen thousand seven hundred twenty-four trauma patients were admitted. The study cohort comprised 604 victims of traumatic cardiopulmonary arrest, 304 as a result of blunt injury and 300 as a result of penetrating injury. Transport time for the study patients was 11+/-6.1 minutes (mean +/- SD). Cardiopulmonary resuscitation was performed on them for 22+/-11 minutes. Three hundred four patients (50%) had resuscitative thoracotomy in the emergency department; 160 patients were taken to the operating room for further resuscitation and treatment of their injuries. Sixteen patients (2.6%) survived to discharge from the hospital; 7 had severe neurologic disabilities. No patient (0/212) with electrical asystole survived. Five of 134 patients with an initial electrical heart rate between 1 and 39 beats/min survived long enough to reach the intensive care unit but died within 48 hours (4 died within 24 hours). No patient survived to leave the hospital if the initial electrical heart rate was less than 40 beats/min. All 16 survivors had an initial heart rate of 40 beats/min or greater.

CONCLUSION

Trauma victims who are pulseless and have asystole or agonal electrical cardiac activity (heart rate <40 beats/min) should be pronounced dead at the scene of injury.

Impairment of cardiac performance by laparoscopy in patients receiving positive end-expiratory pressure

BACKGROUND

The cardiopulmonary effects of the combination of abdominal and thoracic pressures in humans have not been well delineated.

OBJECTIVE

To study the cardiopulmonary effects of 15 mm Hg of intra-abdominal pressure in the presence and absence of 10 cm H20 of positive end-expiratory pressure (PEEP).

DESIGN

Prospective.

SETTING

University hospital.

METHODS

Nine patients undergoing laparoscopic cholecystectomy had pulmonary compliance, cardiac output, exhaled carbon dioxide, and preload (left ventricular end-diastolic volume) determined at 4 points while undergoing ventilation with (1) no PEEP before pneumoperitoneum; (2) 10 cm H20 of PEEP and no pneumoperitoneum; (3) no PEEP and 15 mm Hg of pneumoperitoneum; and (4) 10 cm H20 of PEEP and 15 mm Hg of pneumoperitoneum. Preload and cardiac output were determined by means of transesophageal echocardiography. Pulmonary compliance and exhaled carbon dioxide were determined by an attachment to the end of the endotracheal tube.

MAIN OUTCOME MEASURES

Preload, cardiac output, exhaled carbon dioxide, and pulmonary compliance.

RESULTS

There was no significant change from baseline in preload, cardiac output, or pulmonary compliance when either PEEP or pneumoperitoneum was applied separately. However, there was a significant decrease in preload (P<.01), cardiac output (P = .01), and exhaled carbon dioxide (P =.04) when PEEP and pneumoperitoneum were applied together. Pulmonary compliance was not significantly affected at any of these points.

CONCLUSIONS

There was a significant reduction in preload and cardiac output when there was intra-abdominal pressure of 15 mm Hg in the presence of 10 cm H20 of PEEP. This combination of pressures may pose a contraindication to laparoscopic surgery.

Cardiovascular risk factor screening and intervention in African American adults

The Cardiac Health and Rehabilitation program of St. Thomas Hospital in Nashville, Tennessee, has developed a project to assess the effectiveness of a community-based cardiovascular risk assessment and intervention program directed at African American adults. The specific aim of this program is to assess the feasibility of implementing a community-based cardiovascular disease risk factor reduction program directed at African American adults. Its ultimate goal is to be able to teach African American adults cost-efficient, simple methods of exercise, nutrition, and weight management; smoking cessation; and blood pressure control. The program is expected to raise the African American community's awareness of the importance of modifiable cardiovascular disease risk factors and their effect on cardiac morbidity and mortality. The program is also expected to be able to evaluate the success of cardiovascular disease risk factor intervention and patient satisfaction with the program.

Cohort mortality study of pulp and paper mill workers in British Columbia, Canada

The authors studied a cohort of 30,157 male pulp and paper workers in British Columbia, Canada. Of these, 20,373 worked in kraft mills only, 5,249 in sulfite mills only, and 4,535 in both kraft and sulfite mills. All workers with at least 1 year of employment on January 1, 1950, or thereafter until December 31, 1992, were studied. Standardized mortality ratios (SMRs) were used to compare the mortality rates of the cohort with those of the Canadian male population. Ninety percent confidence intervals (CIs) for the SMRs were obtained. Cancer risks significantly associated with work duration and time from first employment of 15 years or more were observed: 1) total cohort: pleura (SMR = 3.61, 90% CI 1.42-7.58); kidney (SMR = 1.69, 90% CI 1.13-2.43); brain (SMR = 1.51, 90% CI 1.03-2.16); 2) workers in kraft mills only: kidney (SMR = 1.92, 90% CI 1.04-3.26); 3) workers in sulfite mills only: Hodgkin's disease (SMR = 4.79, 90% CI 1.29-12.37); 4) workers ever employed in both kraft and sulfite mills: esophagus (SMR = 1.91, 90% CI 1.00-3.33). These malignancies have been associated with the following known or suspected carcinogens to which pulp and paper workers may have been exposed: asbestos (pleura), biocides (kidney), formaldehyde (kidney, brain, Hodgkin's disease), hypochlorite (esophagus). A nested case-control study with detailed exposure assessment is under way to help determine whether excess risks for specific cancers reflect exposure among subsets of workers.

A prospective, randomized trial of intravenous fat emulsion administration in trauma victims requiring total parenteral nutrition

OBJECTIVE

Intravenous fat infusions are a standard component of total parenteral nutrition (TPN). We studied the effects of withholding fat infusions in trauma patients requiring TPN.

DESIGN

Polytrauma patients receiving TPN were randomized to receive a standard fat emulsion dose (L) or to have fat infusions withheld (NL) for the first 10 days of TPN. The two groups received the same amino acid and carbohydrate dose (isonitrogenous, nonisocaloric).

MATERIALS AND METHODS

Clinical outcome parameters were measured. T-cell function was assessed by measuring lymphokine activated killer and natural killer cell activity.

MEASUREMENTS AND MAIN RESULTS

Demographics including Injury Severity Score (27 +/- 8; 30 +/- 9) and APACHE II scores (23 +/- 6; 22 +/- 5) were similar for the L (n = 30) and NL (n = 27) groups, respectively. Differences (p < 0.05) were found in length of hospitalization (L = 39 +/- 24; NL = 27 +/- 16), intensive care unit length of stay (L = 29 +/- 22; NL = 18 +/- 12), and days on mechanical ventilation (L = 27 +/- 21; NL = 15 +/- 12). The L group had a higher number of infections (72 in 30) than the NL group (39 in 27) and T-cell function was depressed in this group.

CONCLUSIONS

Intravenous fat emulsion infusions during the early postinjury period increased susceptibility to infection, prolonged pulmonary failure, and delayed recovery in critically injured patients. It is not clear whether the improved outcome in the NL group was directly related to withholding the fat infusions or due to the hypocaloric nutritional regimen (underfeeding) these patients received.

Audit of acute upper gastrointestinal haemorrhage: the effects of education and the introduction of a protocol

The aim of this audit was to monitor the effects of the introduction of a protocol for the management of acute upper GI haemorrhage and a teaching programme for House Officers in Ninewells Hospital Dundee. All patients admitted to hospital with a history of acute haematemesis or melaena were included in the study and purpose designed audit forms were completed on all patients. Following an initial six month audit period the protocol and teaching were introduced. A further six months audit was then performed. A total of 310 patients were audited over the two six month periods. The results suggest that the introduction of a management protocol and training, in conjunction with a policy of active endoscopic intervention may reduce the number of out of hours emergency endoscopies and the need for emergency surgery.

Right ventricular volumes overestimate left ventricular preload in critically ill patients

BACKGROUND

Studies have shown right ventricular end-diastolic volume (RVEDV) to be a more accurate estimate of left ventricular preload than pulmonary artery wedge pressure. We prospectively evaluated the ability of RVEDV to predict left ventricular end-diastolic volume (LVEDV) in critically ill patients.

METHODS

Thirty critically ill patients in the surgical intensive care unit underwent concurrent measurement of RVEDV and LVEDV. RVEDV was measured using a residual fraction Swan-Ganz catheter (RF Swan). LVEDV was measured using transesophageal echocardiography with acoustic quantification. Intracardiac, intra-abdominal, and ventilatory pressures were also measured.

RESULTS

RVEDV as measured by the RF Swan was significantly larger (by a factor of 2) than LVEDV (p < 0.0001 analysis of variance). However, the RVEDV and LVEDV were strongly correlated (r = 0.71, p < 0.0001, Pearson's correlation).

CONCLUSIONS

RVEDV from the RF Swan markedly overestimated left ventricular preload. If RVEDV is used as an absolute value for determining preload, patients may be underresuscitated. Transesophageal echocardiography in conjunction with RF Swan can be used to more accurately determine preload and cardiac performance than RF Swan alone in critically ill patients.

Initial small-volume hypertonic resuscitation of shock and brain injury: short- and long-term effects

BACKGROUND

Initial small-volume hypertonic saline resuscitation of a combined hemorrhagic shock and head injury model was studied.

METHODS

Twenty-three sheep underwent hemorrhage (20 mL/kg) and parietal freeze injury followed by initial bolus resuscitation with lactated Ringer's solution (40 mL/kg) or 7.5% hypertonic saline (HS) (4 mL/kg). Cardiac index was maintained with lactated Ringer's solution for either 2 or 24 hours. Parietal lobe water content, blood volume, and blood flow were determined. Intracranial pressure (millimeters of mercury) was followed.

RESULTS

Overall fluid requirements (milliliters per kilogram) were less at 2 and 24 hours with HS resuscitation. Early intracranial pressure was less with HS resuscitation. Brain water contents were similar between groups. Blood flow in injured and blood volume in uninjured parietal lobe were less for HS at 2 hours, although not different at 24 hours.

CONCLUSIONS

Less fluid was needed in the short- and long-term with HS resuscitation. Early intracranial pressure was higher with lactated Ringer's solution resuscitation, possibly in part owing to increased blood volume.

Ca2+-calmodulin binding to mouse alpha1 syntrophin: syntrophin is also a Ca2+-binding protein

Syntrophins are peripheral membrane proteins which have been found associated with dystrophin, the protein product of the Duchenne muscular dystrophy gene locus. Mouse alpha1 syntrophin binds the COOH-terminal domain of dystrophin, and calmodulin inhibits this interaction in a Ca2+-dependent fashion. Where calmodulin binds to syntrophin was investigated by constructing fusion proteins containing different regions of syntrophin's sequence. Syntrophin contains at least two regions which bind calmodulin in different ways. The COOH-terminal 24 residues contain a Ca2+-calmodulin binding site, named CBS-C, which binds calmodulin with an apparent affinity of 18 nM and which is highly conserved in all syntrophins. The amino-terminal 174 residue section of syntrophin contains other calmodulin binding, and binding occurs in either the presence or absence of Ca2+ with an apparent affinity of 100 nM. Syntrophin was shown to bind Ca2+ at two or more sites residing in the amino-terminal 274 residues, and Ca2+ binding to syntrophin affects calmodulin binding at high concentrations of syntrophin. Syntrophin A (residues 4-274) is predominantly a dimer in EGTA. A model of syntrophin's complex interactions with itself (i.e., oligomerization), calmodulin, and Ca2+ is presented.

Colonic stricture in cystic fibrosis unmasked by successful transjugular intrahepatic portosystemic stent shunt (TIPSS)

TIPSS was successfully performed in a 10-year-old female cystic fibrosis (CF) patient with bleeding gastric varices due to portal hypertension; precipitation of portosystemic encephalopathy later unveiled the presence of a latent colonic stricture associated with high potency pancreatic enzymes. The unusual sequence of events resulting from the co-existence of two CF pathologies are described, and the implications of treatment discussed.

Competitive RNA templates for detection and quantitation of growth factors, cytokines, extracellular matrix components and matrix metalloproteinases by RT-PCR

Detection of low-abundance mRNAs by reverse transcription-polymerase chain reaction (RT-PCR) has become a standard technique to determine gene expression by tissues and cells in culture. The ability to determine relative or absolute copy number of specific mRNAs has been difficult due to inadequate internal standards to control for sample-to-sample variation. The use of a synthetic RNA standard with identical sequences to the PCR primers allows reproducible quantitation between samples and assays. By designing multi-sequence templates, several specific mRNAs can be quantitated using a single template. Addition of multiple templates to a single RT reaction allows the quantitation of a large number of targets from as little as 4 micrograms of total RNA. In this report, we present a series of seven primer/template systems to detect and quantitate 52 specific messages, including 26 growth factors and receptors, 8 extracellular matrix components, 10 matrix-modifying enzymes and their inhibitors and 8 cytokines.

Ca2+-calmodulin binds to the carboxyl-terminal domain of dystrophin

The unique COOH-terminal domain of dystrophin (mouse dystrophin protein sequences 3266-3678) was expressed as a chimeric fusion protein (with the maltose-binding protein), and its binding to calmodulin was assessed. This fusion protein, called DysS9, bound to calmodulin-Sepharose, bound biotinylated calmodulin, caused characteristic changes in the fluorescence emission spectrum of dansyl-calmodulin, and had an apparent affinity for dansyl-calmodulin of 54 nM. Binding in each case was Ca2+-dependent. The maltose-binding protein does not bind calmodulin, and thus binding resides in the dystrophin-derived sequences. Deletion mutation experiments further localize the high affinity calmodulin binding to mouse dystrophin protein sequences 3293-3349, and this domain contains regions with chemical characteristics found in the calmodulin-binding sequences in other proteins. The COOH-terminal domain provides sites of attachment of dystrophin to membrane proteins, and calmodulin binding may modulate these interactions.

Endocytosis of fluorescent microspheres by human oesophageal epithelial cells: comparison between normal and inflamed tissue

This paper examines the presence and characteristics of endocytosis by oesophageal epithelial cells. Biopsy specimens from normal and inflamed oesophagus were incubated in organ culture with fluorescent microspheres (0.1 and 0.01 microns diameter). These markers were taken into early endosomes and the lysosomes of both the smaller differentiating prickle cells and the larger mature squamous cells. Confocal and electron microscopy showed that markers passed to the early endosomes and the lysosomes by endocytosis. The process was energy dependent. Larger, 1 micron microspheres adhered to the epithelial cells but were not phagocytosed. Disaggregated cells were analysed by flow cytometry. Microspheres were endocytosed in proportion to the concentration in the culture medium in a dose dependent manner. Cells from inflamed oesophagus were significantly smaller (p = 0.013) and took up significantly more microspheres than cells from normal biopsy specimens (p = 0.015). In conclusion, endocytosis occurs in oesophageal epithelial cells and is increased in inflammation.

PUB1 is a major nuclear and cytoplasmic polyadenylated RNA-binding protein in Saccharomyces cerevisiae

Proteins that directly associate with nuclear polyadenylated RNAs, or heterogeneous nuclear RNA-binding proteins (hnRNPs), and those that associate with cytoplasmic mRNAs, or mRNA-binding proteins (mRNPs), play important roles in regulating gene expression at the posttranscriptional level. Previous work with a variety of eukaryotic cells has demonstrated that hnRNPs are localized predominantly within the nucleus whereas mRNPs are cytoplasmic. While studying proteins associated with polyadenylated RNAs in Saccharomyces cerevisiae, we discovered an abundant polyuridylate-binding protein, PUB1, which appears to be both an hnRNP and an mRNP. PUB1 and PAB1, the polyadenylate tail-binding protein, are the two major proteins cross-linked by UV light to polyadenylated RNAs in vivo. The deduced primary structure of PUB1 indicates that it is a member of the ribonucleoprotein consensus sequence family of RNA-binding proteins and is structurally related to the human hnRNP M proteins. Even though the PUB1 protein is a major cellular polyadenylated RNA-binding protein, it is nonessential for cell growth. Indirect cellular immunofluorescence combined with digital image processing allowed a detailed comparison of the intracellular distributions of PUB1 and PAB1. While PAB1 is predominantly, and relatively uniformly, distributed within the cytoplasm, PUB1 is localized in a nonuniform pattern throughout both the nucleus and the cytoplasm. The cytoplasmic distribution of PUB1 is considerably more discontinuous than that of PAB1. Furthermore, sucrose gradient sedimentation analysis demonstrates that PAB1 cofractionates with polyribosomes whereas PUB1 does not. These results suggest that PUB1 is both an hnRNP and an mRNP and that it may be stably bound to a translationally inactive subpopulation of mRNAs within the cytoplasm.

NAB2: a yeast nuclear polyadenylated RNA-binding protein essential for cell viability

A variety of nuclear ribonucleoproteins are believed to associate directly with nascent RNA polymerase II transcripts and remain associated during subsequent nuclear RNA processing reactions, including pre-mRNA polyadenylation and splicing as well as nucleocytoplasmic mRNA transport. To investigate the functions of these proteins by using a combined biochemical and genetic approach, we have isolated nuclear polyadenylated RNA-binding (NAB) proteins from Saccharomyces cerevisiae. Living yeast cells were irradiated with UV light to covalently cross-link proteins intimately associated with RNA in vivo. Polyadenylated RNAs were then selectively purified, and the covalent RNA-protein complexes were used to elicit antibodies in mice. Both monoclonal and polyclonal antibodies which detect a variety of NAB proteins were prepared. Here we characterize one of these proteins, NAB2. NAB2 is one of the major proteins associated with nuclear polyadenylated RNA in vivo, as detected by UV light-induced cross-linking. Cellular immunofluorescence, using both monoclonal and polyclonal antibodies, demonstrates that the NAB2 protein is localized within the nucleus. The deduced primary structure of NAB2 indicates that it is composed of at least two distinct types of RNA-binding motifs: (i) an RGG box recently described in a variety of heterogeneous nuclear RNA-, pre-rRNA-, mRNA-, and small nucleolar RNA-binding proteins and (ii) CCCH motif repeats related to the zinc-binding motifs of the largest subunit of RNA polymerases I, II, and III. In vitro RNA homopolymer/single-stranded DNA binding studies indicate that although both the RGG box and CCCH motifs bind poly(G), poly(U), and single-stranded DNA, the CCCH motifs also bind to poly(A). NAB2 is located on chromosome VII within a cluster of ribonucleoprotein genes, and its expression is essential for cell growth.

Insulin-dependent diabetes in the NOD mouse model. II. Beta cell destruction in autoimmune diabetes is a TH2 and not a TH1 mediated event

Type I, insulin-dependent diabetes (IDD) in both man and animals results from a specific autoimmune destruction of the pancreatic beta cells involving both humoral and cellular immune mechanisms. The pathognomonic histologic lesion, termed insulitis, is an inflammatory and immune cell infiltrate of the pancreatic islet cells. While recent histological and flow cytometric analyses have identified the cell composition of the infiltrate, the presence of a cell population may not reflect the functional reactivities important for beta cell destruction. In the present study, we have investigated the possible functional reactivities of islet-infiltrating mononuclear cell populations by measuring increased cytokine mRNA usage. Results indicate that 1) cytokine mRNA profiles exhibited by islet-infiltrating cells of female and male NOD mice were quite similar with the exception of IL-6 expression and the marked differences in the levels of IL-2 receptor and IL-1 alpha mRNA, 2) CD4+ T lymphocytes expressed IL-4, presumably IL-5, and occasionally IL-10 mRNA but no detectable IL-2 mRNA, 3) CD8+ T lymphocytes exhibited TNF-beta, perforin and high levels of IFN-gamma, and 4) IL-7 was expressed in the islet at very high levels. These findings, together with our earlier flow cytometric analyses of the islet-infiltrating cells, have permitted construction of a detailed model for the natural history of autoimmune diabetes. Interestingly, this model, based on a TH2- and not a TH1-mediated scheme, questions the more popular concepts currently thought to form the bases of the autoimmune reactions underlying IDD.

A risk-related preventive maintenance system

Recent changes in attitudes concerning medical equipment maintenance place more responsibility for planning appropriate levels of maintenance on the clinical engineer and biomedical equipment technician. A system is described in which maintenance decisions are based on the effects of equipment failure on quality of patient care and potential for injury to patients and staff. It is hoped that development of an acceptable classification scheme will simplify maintenance decisions. Such a system will provide levels of maintenance appropriate to the equipment function in patient care.