Difficult-to-treat (DTR) Pseudomonas aeruginosa harboring Verona-Integron metallo-β-lactamase (blaVIM): infection management and molecular analysis

Pseudomonas aeruginosa harboring Verona Integron-encoded metallo-β-lactamase enzymes (VIM-CRPA) have been associated with infection outbreaks in several parts of the world. In the US, however, VIM-CRPA remain rare. Starting in December 2018, we identified a cluster of cases in our institution. Herein, we present our epidemiological investigation and strategies to control/manage these challenging infections. This study was conducted in a large academic healthcare system in Miami, FL, between December 2018 and January 2022. Patients were prospectively identified via rapid molecular diagnostics when cultures revealed carbapenem-resistant P. aeruginosa. Alerts were received in real time by the antimicrobial stewardship program and infection prevention teams. Upon alert recognition, a series of interventions were performed as a coordinated effort. A retrospective chart review was conducted to collect patient demographics, antimicrobial therapy, and clinical outcomes. Thirty-nine VIM-CRPA isolates led to infection in 21 patients. The majority were male (76.2%); the median age was 52 years. The majority were mechanically ventilated (n = 15/21; 71.4%); 47.6% (n = 10/21) received renal replacement therapy at the time of index culture. Respiratory (n = 20/39; 51.3%) or bloodstream (n = 13/39; 33.3%) were the most common sources. Most infections (n = 23/37; 62.2%) were treated with an aztreonam-avibactam regimen. Six patients (28.6%) expired within 30 days of index VIM-CRPA infection. Fourteen isolates were selected for whole genome sequencing. Most of them belonged to ST111 (12/14), and they all carried blaVIM-2 chromosomally. This report describes the clinical experience treating serious VIM-CRPA infections with either aztreonam-ceftazidime/avibactam or cefiderocol in combination with other agents. The importance of implementing infection prevention strategies to curb VIM-CRPA outbreaks is also demonstrated.

Right Ventricular Assist Device with an Oxygenator for the Management of Combined Right Ventricular and Respiratory Failure: A Systematic Review

BACKGROUND

Severe lung disease frequently presents with both refractory hypoxemia and right ventricular (RV) failure. OxyRVAD is an extra-corporeal membrane oxygenation (ECMO) configuration of RV bypass that also supplements gas exchange. This systematic review summarizes the available literature regarding the use of OxyRVAD in the setting of severe lung disease with associated RV failure.

METHODS

PubMed, Embase, and Google Scholar were queried on September 27th, 2023, for articles describing the use of an OxyRVAD configuration. The main outcome of interest was survival to ICU discharge. Data on the duration of OxyRVAD support and device-related complications were also recorded.

RESULTS

Of 475 identified articles, 33 were retained for analysis. Twenty-one articles were case reports and 12 were case series representing a total of 103 patients. No article provided a comparison group. Most patients (76.4%) were transitioned to OxyRVAD from another type of mechanical support. OxyRVAD was used as a bridge to transplant or curative surgery in 37.4% and as a bridge to recovery or decision in 62.6%. Thirty-one patients (30.1%) were managed with the dedicated single-access dual-lumen ProtekDuo cannula. Median time on OxyRVAD was twelve days (IQR 8-23) and survival to ICU discharge was 63.9%. Device-related complications were infrequently reported.

CONCLUSION

OxyRVAD support is a promising alternative for RV support when gas exchange is compromised with good ICU survival in selected cases. Comparative analyses in patients with RV failure with and without severe lung disease are needed.

Aspergillus fumigatus Epidural Abscess and Postsurgical Wound Infection in an Immunocompetent Host

In this case, we present an immunocompetent patient who had a wound infection secondary to Aspergillus fumigatus after undergoing a neurosurgical procedure that was complicated by an epidural abscess. The patient was treated with voriconazole and responded favorably. We highlight the need for awareness of the possibility of an Aspergillus infection in people without any obvious immunocompromise and advocate for the inclusion of this opportunistic fungus in the workup of postneurosurgical infections and dura-based collections. A brief review of relevant literature is also included.

Analysis of the Physical Characteristics of an Anhydrous Vehicle for Compounded Pediatric Oral Liquids

The paucity of suitable drug formulations for pediatric patients generates a need for customized, compounded medications. This research study was set out to comprehensively analyze the physical properties of the new, proprietary anhydrous oral vehicle SuspendIt® Anhydrous, which was designed for compounding pediatric oral liquids. A wide range of tests was used, including sedimentation volume, viscosity, droplet size after dispersion in simulated gastric fluid, microscopic examination and content uniformity measurements to evaluate the properties of the anhydrous vehicle. The results showed that the vehicle exhibited consistent physical properties under varying conditions and maintained stability over time. This can be attributed to the unique blend of excipients in its formulation, which not only maintain its viscosity but also confer thixotropic behavior. The unique combination of viscous, thixotropic and self-emulsifying properties allows for rapid redispersibility, sedimentation stability, accurate dosing, potential drug solubility, dispersion and promotion of enhanced gastrointestinal distribution and absorption. Furthermore, the vehicle demonstrated long-term sedimentation stability and content uniformity for a list of 13 anhydrous suspensions. These results suggest that the anhydrous oral vehicle could serve as a versatile base for pediatric formulation, potentially filling an important gap in pediatric drug delivery. Future studies can further investigate its compatibility, stability and performance with other drugs and in different clinical scenarios.

IMPACT OF GENDER ON ASSOCIATION BETWEEN RACE AND DISABILITY: THE CALIFORNIA HEALTH INTERVIEW SURVEY (CHIS)

Women generally have higher prevalence of disability than men in later life. Moreover, Blacks and Hispanics usually have higher prevalence of disability than Whites. Little is known about the impact of gender on the association between race and disability. We used 2015-2016 CHIS data, restricted to adults ≥ 65 years old (n=15,044). Disability was classified as present or absent based on responses on questions related to “to physical, mental, and emotional conditions.” Race was classified as: White, Black, Hispanic, Asian, and Other. We estimated sex- and race-specific proportions and 95% confidence intervals (CI) and used sex-specific multivariable logistic regression to examine the associations between race and disability adjusting for age, education, marital status, cigarette smoking, arthritis, hypertension, and diabetes, mental distress, and walking for work or pleasure. All analyses accounted for complex sampling weights. Approximately 52% of women and 47% of men had disability, while 48% of White, 48% of Black, 60% of Hispanic, 43% of Asian, and 50% of Other race responded as having disability. Adjusting for covariates, Hispanic women had 67% higher odds of having disability compared with White women (OR= 1.67, 95% CI= 1.07–2.60), but there were no differences in male counterparts (OR=1.03, 95% CI=0.68-1.56). Compared with White men, men of Asian or Other race had lower odds for disability, while associations were in the opposite direction in female counterparts; however, associations were not statistically significant. Further research is needed to understand higher prevalence of disability among older minority women compared with White women.

Understanding the Early Evolutionary Stages of a Tandem Drosophilamelanogaster-Specific Gene Family: A Structural and Functional Population Study

Gene families underlie genetic innovation and phenotypic diversification. However, our understanding of the early genomic and functional evolution of tandemly arranged gene families remains incomplete as paralog sequence similarity hinders their accurate characterization. The Drosophila melanogaster-specific gene family Sdic is tandemly repeated and impacts sperm competition. We scrutinized Sdic in 20 geographically diverse populations using reference-quality genome assemblies, read-depth methodologies, and qPCR, finding that ∼90% of the individuals harbor 3-7 copies as well as evidence of population differentiation. In strains with reliable gene annotations, copy number variation (CNV) and differential transposable element insertions distinguish one structurally distinct version of the Sdic region per strain. All 31 annotated copies featured protein-coding potential and, based on the protein variant encoded, were categorized into 13 paratypes differing in their 3' ends, with 3-5 paratypes coexisting in any strain examined. Despite widespread gene conversion, the only copy present in all strains has functionally diverged at both coding and regulatory levels under positive selection. Contrary to artificial tandem duplications of the Sdic region that resulted in increased male expression, CNV in cosmopolitan strains did not correlate with expression levels, likely as a result of differential genome modifier composition. Duplicating the region did not enhance sperm competitiveness, suggesting a fitness cost at high expression levels or a plateau effect. Beyond facilitating a minimally optimal expression level, Sdic CNV acts as a catalyst of protein and regulatory diversity, showcasing a possible evolutionary path recently formed tandem multigene families can follow toward long-term consolidation in eukaryotic genomes.

Recovery does not always signal the end of the battle: A case of post SARS-CoV-2 multisystem inflammatory syndrome in an adult

We describe a case of SARS-CoV-2 post-infectious inflammatory syndrome in an adult who presented with multiorgan failure two months following his initial diagnosis of SARS-CoV-2 infection. This case highlights clinician’s early recognition of this devastating sequela and challenges in appropriate management of this patient.

2106. Evaluation of Isavuconazole for the Prophylaxis and Treatment of Invasive Fungal Infections at a Large Academic Medical Center

Background

Isavuconazole is an azole antifungal with in vitro activity against various fungi, including Candida spp, Aspergillus, and Mucormycetes. Currently, isavuconazole is FDA approved for the treatment of invasive aspergillosis and mucormycosis; however, there remains limited data to support prophylaxis use. Compared with other first-line azoles, isavuconazole’s broad spectrum of activity, favorable safety profile, and oral bioavailability makes it an attractive antifungal option. In July 2017, isavuconazole was added to our hospital formulary as a restricted antimicrobial. Since then, we have seen increased use for both prophylaxis and treatment of invasive fungal infections.

Methods

A single-center, retrospective chart review was conducted on adult patients who received at least 1 dose of isavuconazole at The Mount Sinai Hospital between July 1, 2017 and December 31, 2018. The electronic medical record was utilized to collect information on therapeutic indication, dosing, formulation, duration, reasons for switching to isavuconazole, prior antifungals, and proven or probable breakthrough invasive fungal infections (bIFIs) based on EORTG/MTG definitions.

Results

54 patients received 61 courses of isavuconazole. Reasons for switching to isavuconazole are described in Table 1. Eleven patients received inappropriate intravenous formulations and 14% of orders were prescribed isavuconazole without a loading dose (Table 2). We identified 4 proven/probable bIFIs, representing 7.4% of patients and 6.6% of courses (Table 3). All patients died within 60 days of bIFI onset.

Conclusion

Since its addition to hospital formulary, we have observed varying isavuconazole prescribing practices, highlighting the need for improved antifungal stewardship. Rates of bIFIs on isavuconazole were lower than previously reported studies. Additional studies are needed to provide guidance on isavuconazole use and determine its role as prophylaxis therapy.

Disclosures

All authors: No reported disclosures.

266. Implementation and Evaluation of a Pharmacist-Managed Pediatric Vancomycin Protocol

Background

Pediatric studies have shown that pharmacist-guided vancomycin dosing leads to reduction in time to initial target vancomycin trough, duration of vancomycin therapy, time to clinical stability, and shorter hospital stay. At Boston Medical Center, 65% of pediatric patients receiving vancomycin did not achieve initial therapeutic troughs between 10 and 20 μg/mL from October 1, 2016 to September 30, 2017. Through implementation of a pharmacist-managed pediatric vancomycin protocol, the project aim was to increase the percentage of patients achieving initial therapeutic troughs from 35% to 60% and percentage of patients achieving therapeutic troughs within 3 days from 67% to 90% by May 1, 2018. Secondary aims included reducing the incidence of supratherapeutic troughs from 10% to 5% and maintaining the incidence of vancomycin-associated nephrotoxicity (VAN) at 0%.

Methods

A quality improvement (QI) initiative based on the Institute for Healthcare Improvement Model was utilized, testing change through Plan-Do-Study-Act (PDSA) cycles. In PDSA cycle 1, pharmacists designed and implemented a standardized vancomycin dosing protocol for pediatric patients. In PDSA cycle 2, the addition of area under the curve (AUC)-guided dosing was implemented in select patients. Process and balancing measures included percentage of appropriately drawn vancomycin troughs, provider adherence to the new dosing protocol, and incidence of supratherapeutic troughs.

Results

A total of 32 pediatric patients were assessed. Compared with baseline data, percentage of patients achieving initial therapeutic troughs increased from 35% to 44% and percentage of patients achieving therapeutic troughs within 3 days increased from 67% to 92%. The incidence of supratherapeutic troughs decreased from 10% to 0% and the incidence of vancomycin-associated nephrotoxicity was maintained at 0%.

Conclusion

Standardized initial vancomycin dosing with increased pharmacy involvement led to more patients achieving initial therapeutic troughs, shorter times to therapeutic troughs, and a reduction in supratherapeutic troughs. Next steps include hospital-wide implementation of a pediatric vancomycin per pharmacy protocol.

Disclosures

All authors: No reported disclosures.

Evaluation of mobile digital light-emitting diode fluorescence microscopy in Hanoi, Viet Nam

SETTING

Hanoi Lung Hospital, Hanoi, Viet Nam.

OBJECTIVE

To compare the accuracy of CellScopeTB, a manually operated mobile digital fluorescence microscope, with conventional microscopy techniques.

DESIGN

Patients referred for sputum smear microscopy to the Hanoi Lung Hospital from May to September 2013 were included. Ziehl-Neelsen (ZN) smear microscopy, conventional light-emitting diode (LED) fluorescence microscopy (FM), CellScopeTB-based LED FM and Xpert(®) MTB/RIF were performed on sputum samples. The sensitivity and specificity of microscopy techniques were determined in reference to Xpert results, and differences were compared using McNemar's paired test of proportions.

RESULTS

Of 326 patients enrolled, 93 (28.5%) were Xpert-positive for TB. The sensitivity of ZN microscopy, conventional LED FM, and CellScopeTB-based LED FM was respectively 37.6% (95%CI 27.8-48.3), 41.9% (95%CI 31.8-52.6), and 35.5% (95%CI 25.8-46.1). The sensitivity of CellScopeTB was similar to that of conventional LED FM (difference -6.5%, 95%CI -18.2 to 5.3, P = 0.33) and ZN microscopy (difference -2.2%, 95%CI -9.2 to 4.9, P = 0.73). The specificity was >99% for all three techniques.

DISCUSSION

CellScopeTB performed similarly to conventional microscopy techniques in the hands of experienced TB microscopists. However, the sensitivity of all sputum microscopy techniques was low. Options enabled by digital microscopy, such as automated imaging with real-time computerized analysis, should be explored to increase sensitivity.

Graft arterial stenosis in kidney en bloc grafts from very small pediatric donors: incidence, timing, and role of ultrasound in screening

In previous studies with different donor selection criteria and noncontemporary surgical techniques, graft arterial stenosis (GAS) has been reported to occur more frequently in adult recipients of pediatric en bloc renal allografts (EBKT) as compared to single adult donor allografts. The purpose of our study was to evaluate the incidence of GAS within our EBKT recipient population and to evaluate clinical and imaging features of those cases with GAS. In a retrospective cohort study, we analyzed 182 EBKT performed at a single institution. We identified cases of suspected GAS based on clinical factors, lab results, and noninvasive imaging. Diagnosis of GAS was confirmed by digital subtraction angiography. Two EBKT recipients (1.1% of 182) had angiographically confirmed GAS at 2.5 and 4.5 months after transplant. In both cases, the stenoses were short segment within the proximal (perianastomotic) donor aorta, color Doppler ultrasound demonstrated peak systolic velocities of >400 cm/s, and poststenotic parvus tardus waveforms were present. Both patients underwent angioplasty and demonstrated postintervention improvement in renal function and blood pressure. Restenosis did not occur during follow up. In conclusion, recipients of EBKT have a low incidence of GAS, similar to the lowest reported for adult single allografts.

Performance of the Tachyon Time-of-Flight PET Camera

We have constructed and characterized a time-of-flight Positron Emission Tomography (TOF PET) camera called the Tachyon. The Tachyon is a single-ring Lutetium Oxyorthosilicate (LSO) based camera designed to obtain significantly better timing resolution than the ~ 550 ps found in present commercial TOF cameras, in order to quantify the benefit of improved TOF resolution for clinically relevant tasks. The Tachyon's detector module is optimized for timing by coupling the 6.15 × 25 mm² side of 6.15 × 6.15 × 25 mm³ LSO scintillator crystals onto a 1-inch diameter Hamamatsu R-9800 PMT with a super-bialkali photocathode. We characterized the camera according to the NEMA NU 2-2012 standard, measuring the energy resolution, timing resolution, spatial resolution, noise equivalent count rates and sensitivity. The Tachyon achieved a coincidence timing resolution of 314 ps +/- ps FWHM over all crystal-crystal combinations. Experiments were performed with the NEMA body phantom to assess the imaging performance improvement over non-TOF PET. The results show that at a matched contrast, incorporating 314 ps TOF reduces the standard deviation of the contrast by a factor of about 2.3.

Pancreatic cystic lesions and guidelines: a review

No abstract available.

Effect of 9p21.3 coronary artery disease locus neighboring genes on atherosclerosis in mice

BACKGROUND

The human 9p21.3 chromosome locus has been shown to be an independent risk factor for atherosclerosis in multiple large-scale genome-wide association studies, but the underlying mechanism remains unknown. We set out to investigate the potential role of the 9p21.3 locus neighboring genes, including Mtap, the 2 isoforms of Cdkn2a, p16Ink4a and p19Arf, and Cdkn2b, in atherosclerosis using knockout mice models.

METHODS AND RESULTS

Gene-targeted mice for neighboring genes, including Mtap, Cdkn2a, p19Arf, and Cdkn2b, were each bred to mice carrying the human APO*E3 Leiden transgene that sensitizes the mice for atherosclerotic lesions through elevated plasma cholesterol. We found that the mice heterozygous for Mtap developed larger lesions compared with wild-type mice (49623±21650 versus 18899±9604 μm(2) per section [mean±SD]; P=0.01), with morphology similar to that of wild-type mice. The Mtap heterozygous mice demonstrated changes in metabolic and methylation profiles and CD4(+) cell counts. The Cdkn2a knockout mice had smaller lesions compared with wild-type and heterozygous mice, and there were no significant differences in lesion size in p19Arf and Cdkn2b mutants compared with wild type. We observed extensive, tissue-specific compensatory regulation of the Cdkn2a and Cdkn2b genes among the various knockout mice, making the effects on atherosclerosis difficult to interpret.

CONCLUSIONS

Mtap plays a protective role against atherosclerosis, whereas Cdkn2a appears to be modestly proatherogenic. However, no relation was found between the 9p21 genotype and the transcription of 9p21 neighboring genes in primary human aortic vascular cells in vitro. There is extensive compensatory regulation in the highly conserved 9p21 orthologous region in mice.

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

Davalintide (AC2307), a novel amylin-mimetic peptide: enhanced pharmacological properties over native amylin to reduce food intake and body weight

OBJECTIVE

The current set of studies describe the in vivo metabolic actions of the novel amylin-mimetic peptide davalintide (AC2307) in rodents and compares these effects with those of the native peptide.

RESEARCH DESIGN AND METHODS

The anti-obesity effects of davalintide were examined after intraperitoneal injection or sustained peripheral infusion through subcutaneously implanted osmotic pumps. The effect of davalintide on food intake after lesioning of the area postrema (AP) and neuronal activation as measured by c-Fos, were also investigated.

RESULTS

Similar to amylin, davalintide bound with high affinity to amylin, calcitonin and calcitonin gene-related peptide receptors. Acutely, davalintide displayed greater suppression of dark-cycle feeding and an extended duration of action compared with amylin (23 versus 6 h). Davalintide had no effect on locomotor activity or kaolin consumption at doses that decreased food intake. Davalintide-induced weight loss through infusion was dose dependent, durable up to 8 weeks, fat-specific and lean-sparing, and was associated with a shift in food preference away from high-fat (palatable) chow. Metabolic rate was maintained during active weight loss. Both davalintide and amylin failed to suppress food intake after lesioning of the AP and activated similar brain nuclei, with davalintide displaying an extended duration of c-Fos expression compared with amylin (8 versus 2 h).

CONCLUSION

Davalintide displayed enhanced in vivo metabolic activity over amylin while retaining the beneficial properties possessed by the native molecule. In vitro receptor binding, c-Fos expression and AP lesion studies suggest that the metabolic actions of davalintide and amylin occur through activation of similar neuronal pathways.

OpenPET: A Flexible Electronics System for Radiotracer Imaging

We present the design for OpenPET, an electronics readout system designed for prototype radiotracer imaging instruments. The critical requirements are that it has sufficient performance, channel count, channel density, and power consumption to service a complete camera, and yet be simple, flexible, and customizable enough to be used with almost any detector or camera design. An important feature of this system is that each analog input is processed independently. Each input can be configured to accept signals of either polarity as well as either differential or ground referenced signals. Each signal is digitized by a continuously sampled ADC, which is processed by an FPGA to extract pulse height information. A leading edge discriminator creates a timing edge that is "time stamped" by a TDC implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc. As all of this processing is controlled by firmware and software, it can be modified / customized easily. The system is open source, meaning that all technical data (specifications, schematics and board layout files, source code, and instructions) will be publicly available.

A large series, resection controlled study to assess the value of radial EUS in restaging gastroesophageal cancer following neoadjuvant chemotherapy

The true value of endoscopic ultrasound (EUS) post-neoadjuvant chemotherapy for esophageal carcinoma is not established. Superior loco-regional detail may yield useful staging and prognostic information but information on its accuracy, as compared with computed tomography (CT), remains undefined and limited by small study size. We prospectively studied 109 patients with gastroesophageal cancer; 99 of whom were undergoing surgery. All had EUS and helical CT imaging before and after neoadjuvant chemotherapy and the results were compared with pathological staging of resected specimens. Tumor response was assessed by the reduction in maximal tumor depth at EUS and correlated with patient survival. There was no difference in T and N stage accuracies between EUS and CT following neoadjuvant chemotherapy. manova showed a reduction in maximal tumor depth by > 50% at EUS to be associated with longer survival (relative risk = 0.48, P < 0.05). EUS responders had a median survival of 38 months compared to 30 months for non-responders (P < 0.05). The identification of lymphadenopathy at radial EUS was not predictive of survival. This large series study demonstrates the staging accuracy of CT and non-biopsy EUS in the setting of neoadjuvant chemotherapy for gastroesophageal cancer to be equivalent and poor. An endosonography may contribute useful clinical information in respect of potential survival. It is questionable whether radial EUS should be included in protocols for restaging.

The preferred choice for radial endosonographic staging of esophageal cancer: standard echoendoscope or nonoptic esophagoprobe?

BACKGROUND

The nonoptic esophagoprobe has been reported to be comparable to the standard echoendoscope in esophageal cancer staging, with a superior advantage of traversing more stenotic tumors because of its smaller diameter. The aim of this study was to see whether its use in a general population of esophageal cancer patients confers any significant clinical benefit.

METHODS

Five hundred seventy-seven consecutive patients referred for initial locoregional staging of esophageal cancer were analyzed retrospectively. Comparisons were made between the standard echoendoscope and the esophagoprobe.

RESULTS

Complete staging (95.2% vs 77.5%; p < 0.001) was significantly higher in the esophagoprobe group compared with that of the standard echoendoscope group (315 and 262 patients, respectively). In 146 patients with histopathologic verification without prior chemotherapy or radiotherapy, the esophagoprobe was comparable in T-staging accuracy to the standard echoendoscope in those with traversable tumors (89.2% vs. 82.8%; p = 0.213). However, the presence of a nontraversable stricture significantly decreased standard echoendoscope T-staging accuracy compared with a traversable stricture (33.3% vs. 82.8%, respectively; p < 0.001). The esophagoprobe also picked more advanced tumors and distal nodes.

CONCLUSIONS

The esophagoprobe is more accurate than the standard echoendoscope in the T staging of esophageal cancer because of its higher likelihood of traversing tumor stenosis. It can potentially reduce the necessity for dilation in stenotic tumors by four to five times. We propose using the esophagoprobe as the first choice for radial endoscopic ultrasound staging of esophageal cancer.

Percutaneous endoscopic gastrostomy outcomes: can patient profiles predict mortality and weaning?

INTRODUCTION

The benefits of percutaneous endoscopic gastrostomy (PEG) remain controversial. Patient selection is important to identify those who will benefit from PEG. This study aims to identify patient factors that may help in patient selection for PEG.

METHODS

Patients who underwent PEG at the Gastroenterology Unit of Tan Tock Seng Hospital, Singapore, from January 1998 to December 1999, were identified. Multiple logistic regression was used to predict patient's outcomes.

RESULTS

There were 106 (61 male) patients with a mean follow-up period of 465 days (range 3-1,410 days). The mean patient age was 64.5 years (range 17-94 years). The 30-day, six-month, one-year and two-year mortality rates were 7.5 percent, 26.4 percent, 35.8 percent and 46.2 percent, respectively. Older age (p-value is 0.023), presence of bedsores (p-value is 0.042) and abnormal nutritional status based on body mass index less than 20 kg/square metres (p-value is 0.001) were predictive of mortality. 26 percent of patients were able to wean off PEG in an average period of 185 days (range 3-870 days). Patients were generally younger (p-value is 0.003) and had better renal function (p-value is 0.047).

CONCLUSION

Older age, poor nutritional status and presence of bedsores were predictors of poor outcome. Younger age and preserved renal function were significant predictors of weaning off PEG feeding.

Antiobesity action of peripheral exenatide (exendin-4) in rodents: effects on food intake, body weight, metabolic status and side-effect measures

BACKGROUND

Exenatide (exendin-4) is an incretin mimetic currently marketed as an antidiabetic agent for patients with type 2 diabetes. In preclinical models, a reduction in body weight has also been shown in low-fat-fed, leptin receptor-deficient rodents.

OBJECTIVE

To more closely model the polygenic and environmental state of human obesity, we characterized the effect of exenatide on food intake and body weight in high-fat-fed, normal (those with an intact leptin signaling system) rodents. As glucagon-like peptide-1 receptor agonism has been found to elicit behaviors associated with visceral illness in rodents, we also examined the effect of peripheral exenatide on kaolin consumption and locomotor activity.

METHODS AND RESULTS

High-fat-fed C57BL/6 mice and Sprague-Dawley rats were treated with exenatide (3, 10 and 30 microg/kg/day) for 4 weeks via subcutaneously implanted osmotic pumps. Food intake and body weight were assessed weekly. At 4 weeks, body composition and plasma metabolic profiles were measured. Kaolin consumption and locomotor activity were measured in fasted Sprague-Dawley rats following a single intraperitoneal injection of exenatide (0.1-10 microg/kg). Exenatide treatment in mice and rats dose-dependently decreased food intake and body weight; significant reductions in body weight gain were observed throughout treatment at 10 and 30 microg/kg/day (P<0.05). Decreased body weight gain was associated with a significant decrease in fat mass (P<0.05) with sparing of lean tissue. Plasma cholesterol, triglycerides and insulin were also significantly reduced (P<0.05). Exenatide at 10 microg/kg significantly reduced food intake (P<0.05) but failed to induce kaolin intake. In general, locomotor activity was reduced at doses of exenatide that decreased food intake, although a slightly higher dose was required to produce significant changes in activity.

CONCLUSION

Systemic exenatide reduces body weight gain in normal, high-fat-fed rodents, a model that parallels human genetic variation and food consumption patterns, and may play a role in metabolic pathways mediating food intake.

Endoscopic ultrasound-guided fine needle aspiration cytology of pancreatic neuroendocrine tumours: cytomorphological and immunocytochemical evaluation

OBJECTIVES

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) is increasingly used in preoperative localization and diagnosis of pancreatic neoplasms including neuroendocrine tumours (NETs). The objective of the present study was to identify the cytological features of pancreatic NETs obtained by EUS-FNA.

METHODS

The study group consisted of nine cases of pancreatic tumours correctly diagnosed or strongly suggestive of NETs based on EUS-FNA. Cytological smears were retrospectively reviewed. The clinical data and immunocytochemical stains applied to the cell block preparations were also reviewed and examined.

RESULTS

All cases except one showed characteristic cytomorphological features sufficient for their recognition and separation from pancreatic adenocarcinoma and other lesions. The most helpful cytological features that facilitated the cytological diagnosis of NET were a richly cellular aspirate with a monotonous, poorly cohesive population of small cells with a speckled or dusty chromatin pattern and plasmacytoid morphology. The neuroendocrine differentiation of these tumours was further confirmed by immunocytochemistry.

CONCLUSION

EUS-FNA is a valuable method in the recognition of pancreatic NETs. By adherence to the characteristic cytomorphological criteria of pancreatic NET together with collection of suitable material for ancillary immunocytochemical stains, cytopathologists could reach a correct diagnosis in most instances.

Drug users talk about HIV testing: motivating and deterring factors

Injection drug use plays a critical role in the spread of HIV/AIDS, with an estimated 19,000 drug users infected each year. Counselling and testing services can be an important gateway for engaging HIV-infected individuals into medical care and can positively influence the preventive behaviours of IDUs. This study seeks to document and understand the complexity and range of motivations and deterrents to HIV testing among IDUs. Participants were recruited using a convenience sampling method. Interviews consisted of a qualitative guide and a quantitative survey to collect HIV testing histories, sex and drug risk behaviours, and demographic information. Interview data was coded and content analyzed to identify emerging themes and clarify the processes that drug users employ in deciding whether or not to test. Sixty-six drug users were interviewed. The sample reported a median of four lifetime HIV tests. Participants described a range of motivating and deterring factors to HIV testing across personal, interpersonal and structural categories. Drug users' decision to test is influenced by a complex network of factors. Better understanding of these motivators and deterrents can help providers develop a more holistic approach to targeting this high-risk population for HIV prevention efforts.

Effects of charged amino acids at b and c heptad positions on specificity and stability of four-chain coiled coils

An understanding of the balance of chemical forces responsible for protein stability and specificity of structure is essential for the success of efforts in protein design. Specifically, electrostatic interactions between charged amino acids have been explored extensively to understand the contribution of this force to protein stability. Much research on the importance of electrostatic interactions as specificity and stability determinants in two-stranded coiled coils has been done, but there remains significant controversy about the magnitude of the attractive forces using such systems. We have developed a four-stranded coiled-coil system with charged residues incorporated at b and c heptad positions to explore the role of charge interactions. Here, we test quantitatively the effects of varying sidechain length on the magnitude of such electrostatic interactions. We synthesized peptides containing either aspartate or ornithine at both b and c heptad positions and tested their ability to self-associate and to hetero-associate with one another and with peptides containing glutamate or lysine at the same positions. We find that interactions between glutamate and either lysine or ornithine are more favorable than the corresponding interactions involving aspartate. In each case, charged interactions provide additional stability to coiled coils, although helix propensity effects may play a significant role in determining the overall stability of these structures.

Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Prevalence of Helicobacter pylori in peptic ulcer disease in a Singapore hospital

INTRODUCTION

High Helicobacter pylori (H. pylori) prevalence is well documented among peptic ulcer patients. However, there have been recent reports of declining H. pylori infection rates in developed countries. Based on previous local data in a different hospital, H. pylori prevalence was 66% in gastric ulcer, 86% in duodenal ulcer and 75% in combined gastric and duodenal ulcers. Our present study aims to review the recent H. pylori prevalence in peptic ulcer patients in a Singapore hospital. H. pylori infection rate in relation to sex, age, non-steroidal anti-inflammatory drug (NSAID) use and race were also examined.

METHODS

Over a 6-month period, patients diagnosed with peptic ulcer by oesophagogastroduodenoscopy were selected. Relevant information was obtained from case notes retrieved from the Medical Records Office. H. pylori status was assessed by rapid urease test (CLOtest) and/or histology. Exclusion criteria were(1) history of peptic ulcer(2), active bleeding(3), cancer or(4) recent use of antibiotics or proton pump inhibitors.

RESULTS

107 peptic ulcer patients were selected; 53 gastric ulcer, 47 duodenal ulcer and 7 with combined gastric and duodenal ulcers. Overall H. pylori prevalence was 67.9%(36/53), 85.1%(40/47) and 85.7%(6/7) respectively. Except for the gender variable in gastric ulcer group, age, race and NSAID use was not found to influence H. pylori prevalence.

CONCLUSIONS

The prevalence of H. pylori among our peptic ulcer patients is slightly lower compared to overseas studies but the local trend,when compared indirectly to another previous local study did not appear to have changed much. Reasons for the lower H. pylori infection rate in comparison to overseas studies are discussed. The lower H. pylori prevalence among female gastric ulcer patients may be due to the higher prevalence of NSAID use.

Structure-based design of an osteoclast-selective, nonpeptide src homology 2 inhibitor with in vivo antiresorptive activity

Targeted disruption of the pp60(src) (Src) gene has implicated this tyrosine kinase in osteoclast-mediated bone resorption and as a therapeutic target for the treatment of osteoporosis and other bone-related diseases. Herein we describe the discovery of a nonpeptide inhibitor (AP22408) of Src that demonstrates in vivo antiresorptive activity. Based on a cocrystal structure of the noncatalytic Src homology 2 (SH2) domain of Src complexed with citrate [in the phosphotyrosine (pTyr) binding pocket], we designed 3',4'-diphosphonophenylalanine (Dpp) as a pTyr mimic. In addition to its design to bind Src SH2, the Dpp moiety exhibits bone-targeting properties that confer osteoclast selectivity, hence minimizing possible undesired effects on other cells that have Src-dependent activities. The chemical structure AP22408 also illustrates a bicyclic template to replace the post-pTyr sequence of cognate Src SH2 phosphopeptides such as Ac-pTyr-Glu-Glu-Ile (1). An x-ray structure of AP22408 complexed with Lck (S164C) SH2 confirmed molecular interactions of both the Dpp and bicyclic template of AP22408 as predicted from molecular modeling. Relative to the cognate phosphopeptide, AP22408 exhibits significantly increased Src SH2 binding affinity (IC(50) = 0.30 microM for AP22408 and 5.5 microM for 1). Furthermore, AP22408 inhibits rabbit osteoclast-mediated resorption of dentine in a cellular assay, exhibits bone-targeting properties based on a hydroxyapatite adsorption assay, and demonstrates in vivo antiresorptive activity in a parathyroid hormone-induced rat model.

Development of a new lysis solution for releasing genomic DNA from bacterial cells for DNA amplification by polymerase chain reaction

A new lysis solution designated TZ, consisting of 2.0% Triton X-100 plus 2.5 mg sodium azide/ml in 0.1 M Tris-HCl buffer at pH 8.0, yielded higher levels of genomic DNA from Escherichia coli O157:H7 cells compared with a number of other commonly used cell lysis methods. Ethidium bromide stained DNA bands resulting from PCR amplification of target DNA from 100 CFU of E. coli O157:H7 were readily detected following electrophoresis of agarose gels. In contrast, conventional cell lysis methods failed to detect target DNA from 100 CFU after PCR amplification. The new solution was highly effective for lysing cell suspensions of Salmonella enteritidis, Pseudomonas putida, Lysteria monocytogenes and Psychrobacter immobilis.

Helicobacter pylori eradication with lansoprazole, amoxycillin and clarithromycin: testing an ideal regimen in a multicultural south east Asian population and examining factors potentially influencing eradication

BACKGROUND

From European and North American data, it is recommended in the Asia Pacific consensus statement, that one week therapy with a proton pump inhibitor, amoxycillin and clarithromycin be used for Helicobacter pylori eradication, in areas of high metronidazole resistance. The efficacy of this regimen is unknown in Singapore.

AIM

To assess the efficacy, safety and compliance of an H. pylori eradication regimen and examine clinical factors that potentially determine eradication.

METHODS

Consecutive outpatients from a multicultural, south east Asian, population with H. pylori infection, with or without peptic ulcer, were treated with lansoprazole 30 mg, amoxycillin 1 gm, clarithromycin 500 mg, twice a day for seven days. Eradication was assessed by either rapid urease, histology or urea breath test. Compliance and side effects were recorded. The eradication rate and effect of ethnicity, age, sex, usage of alcohol, smoking and non-steroidal anti-inflammatory drugs, history of ulcer and endoscopic diagnosis on eradication were examined by univariate and multivariate analysis.

RESULTS

Of 113 patients, the eradication rate by intention to treat was 98/113 (87%) (95% confidence interval [CI] 80-93%) and per protocol was 98/106 (92%) (95% CI 87-97%). Using Fisher's exact test, eradication was more successful in Chinese (intention to treat and per protocol respectively p=0.02 and p<0.001) compared to non-Chinese. By logistic regression analysis ethnicity was an independent factor associated with eradication success (p=0.0025). Side effects occurred in five (4.4%), resulting in cessation of treatment.

CONCLUSIONS

This one week eradication regimen is safe and effective in south east Asians. Chinese ethnicity may be associated with a higher likelihood of eradication success.

Generational differences in psychosocial adaptation and predictors of psychological distress in a population of recent Vietnamese immigrants

While first-wave Vietnamese immigrants adapted well to life in the United States, subsequent immigrants have had greater adjustment difficulties, including more evidence of psychological distress. This study aimed to analyze psychosocial adaptation differences among three generations of recent Vietnamese immigrants, as well as to examine predictors of mental distress in the sample as a whole. A community sample of 184 recent Vietnamese immigrants, categorized as either elderly, middle-aged, or young adults, was assessed for levels of psychological distress, including depression, anxiety, and PTSD, as well as family conflict, dissatisfaction with life in the U.S., acculturation and biculturalism, social support, coping, and premigratory stressors. Young Vietnamese adults were most acculturated, most bicultural, and reported themselves as healthiest and least depressed. They were most often working, least often on welfare, and had the highest family income. However, they also reported most dissatisfaction with their current lives in the U.S. and most family conflict. Regression analysis explaining approximately one-quarter of the variance in mental distress implicated current dissatisfaction with and lack of adjustment of life in the United States, as well as greater acculturation and increased family conflict. Although young adults scored significantly higher than other generations on most of the risk factors for psychological distress, they appeared to be buffered against poorer mental health outcomes by factors of generation and perceived positive overall well-being. In terms of testing a predictive model of psychological distress, this study found current adjustment factors significantly more important in determining mental health outcomes than premigratory stressors such as war-related traumas.