A237 STATIN USE IN LIVER TRANSPLANT: INDICATION, USE, AND IMPACT OF STATIN THERAPY ON PATIENT OUTCOMES

Background

Cardiovascular and metabolic diseases are prevalent among patients with chronic liver disease (CLD) and contribute to adverse outcomes and mortality. Prior studies have hypothesized statin therapy improves liver transplant (LT) survival due to anti-inflammatory properties and reduced cardiac risk. Evidence for use of statins in this population is limited as acute liver failure or decompensated cirrhosis is considered a contraindication. Despite evidence supporting statin therapy in CLD their use remains inconsistent.

Purpose

Our study aimed to evaluate the indication and rate of statin use in patients both pre- and post-LT, as well as the impact on post-LT patient survival, graft failure, and post-LT cardiovascular and metabolic disease.

Method

This was a retrospective cohort study of adult LT recipients at the University of Alberta, Edmonton, Canada between 2005 and 2020. Exclusion criteria included pre-transplant acute liver failure, multi-visceral transplant, and re-transplant. Demographic, pharmaceutical and clinical data was collected through review of electronic medical records. Primary endpoints included rate of statin use, post-LT patient survival, and graft failure; secondary endpoints included development of cardiac disease, dyslipidemia, and metabolic syndrome post-LT.

Result(s)

We identified 868 patients meeting inclusion criteria; 596 (68.7%) were male, 713 (82.3%) were Caucasian, and median age at transplant was 55. The most common indication for LT was hepatocellular carcinoma in 291 patients (33.5%), followed by Hepatitis C Virus (24.0%), and alcohol liver disease (16.9%). There were no significant demographic differences between those who were and were not on statin therapy. In the pre-LT period only 3% of patients were on statins, despite 7% of patients having dyslipidemia and 24% having diabetes. A total of 261 patients (29.9%) were placed on statins post-LT. The use of statins post-LT was associated with decreased mortality (OR 0.433, 95% CI [0.302-0.622], p<0.001) and decreased graft failure (OR 0.398, 95% CI [0.276-0.574], p<0.001), however it was also associated with increased graft rejection (OR 1.40, 95% CI [1.02-1.93], p=0.039). There were no significant differences in the development of dyslipidemia, metabolic syndrome or cardiac events in post-LT patients regardless of statin use.

Conclusion(s)

In our study we identified an association between statin use in the post-LT setting and improved mortality and graft survival. We did not find an association with improved cardiac or metabolic outcomes. The negative association between statin use and post-LT rejection may reflect detection bias as patients with rejection are closely monitored. We also identified a discrepancy between the number of patients with indication for statin use and those who were on statins both pre and post LT, reflecting underutilization consistent with prior literature. Additional studies are required to elucidate the role of statin medications in the transplant hepatologists armamentarium.

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Disclosure of Interest

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A224 COVID-19 INFECTION IN LIVER TRANSPLANT RECIPIENTS: CLINICAL FEATURES, HOSPITALIZATION, AND MORTALITY FROM A CANADIAN MULTICENTRE COHORT

Background

The COVID-19 pandemic has brought significant challenges to clinicians caring for liver transplant (LT) recipients. Researchers have sought to better understand the risk and clinical outcomes of LT recipients infected with COVID-19 globally, however, there is a paucity of data from within Canada.

Aims

Our multi-center study aims to examine the characteristics and clinical outcomes of LT patients with COVID-19 in Canada.

Methods

We identified a retrospective cohort of adult LT recipients with RT-PCR confirmed COVID-19 from 7 Canadian tertiary care centers between March 2020 and June 2021. Demographic and clinical data were compiled by clinicians within those centers. We identified liver enzyme profile at the time of COVID-19 infection, immunosuppression type and post-infection adjustments, rate of hospitalization, ICU admission, mechanical ventilation, and death.

Results

A total of 49 patients with a history of LT and COVID-19 infection were identified. Twenty nine patients (59%) were male, the median time from LT was 66 months (1, 128) and the median age at COVID-19 infection was 59 years (52, 65). At COVID-19 diagnosis, the median ALT was 37 U/L (21, 41), AST U/L was 34 (20, 37), ALP U/L was 156 (88, 156), Total Bilirubin was 11 umol/L (7, 14), and INR was 1.1 (1.0, 1.1). The majority of patients (92%) were on tacrolimus monotherapy or a combination of tacrolimus and mycophenolate mofetil (MMF); median tacrolimus level at COVID-19 diagnosis was 5.3 ug/L (4.0, 8.1). Immunosuppression was modified in 8 (16%) patients post-infection; either the tacrolimus dose was reduced or MMF was held. One patient developed acute cellular rejection which recovered after re-initiation of the prior regimen. Eighteen patients (37%) required hospitalization, 6 (12%) were treated with dexamethasone, and 3 (6%) required ICU admission and mechanical ventilation. Four patients (8%) died due to complications of COVID-19. On univariate analysis, neither age, sex, co-morbidities nor duration post-transplant were associated with risk of hospitalization.

Conclusions

In our national retrospective study, approximately 40% of patients required hospitalization with a mortality rate of &lt; 10%. Previous studies have shown proximity to LT as an independent factor for mortality with COVID-19; the median time from LT for our patients was 5 years, which may explain the lower mortality rate. Of note, the median tacrolimus levels were much lower in comparison to the target of 8–10 ug/L used in the first year post-transplant. As the landscape of COVID-19 changes with vaccination, evolving treatments, and increasing rates of variant transmission, additional studies are required to continue identifying trends in clinical outcomes.

Funding Agencies

None

Beam particle identification and tagging of incompletely stripped heavy beams with HEIST

A challenge preventing successful inverse kinematics measurements with heavy nuclei that are not fully stripped is identifying and tagging the beam particles. For this purpose, the HEavy ISotope Tagger (HEIST) has been developed. HEIST utilizes two micro-channel plate timing detectors to measure the time-of-flight, a multi-sampling ion chamber to measure energy loss, and a high-purity germanium detector to identify isomer decays and calibrate the isotope identification system. HEIST has successfully identified ¹⁹⁸Pb and other nearby nuclei at energies of about 75 MeV/A. In the experiment discussed, a typical cut containing 89% of all ¹⁹⁸Pb⁸⁰⁺ in the beam had a purity of 86%. We examine the issues of charge state contamination. The observed charge state populations of these ions are presented and, using an adjusted beam energy, are well described by the charge state model GLOBAL.

Long-term colonisation with donor bacteriophages following successful faecal microbial transplantation

BACKGROUND

Faecal microbiota transplantation (FMT) is used in the treatment of recurrent Clostridium difficile infection. Its success is typically attributed to the restoration of a diverse microbiota. Viruses (including bacteriophages) are the most numerically dominant and potentially the most diverse members of the microbiota, but their fate following FMT has not been well studied.

RESULTS

We studied viral transfer following FMT from 3 donors to 14 patients. Recipient viromes resembled those of their donors for up to 12 months. Tracking individual bacteriophage colonisation revealed that engraftment of individual bacteriophages was dependent on specific donor-recipient pairings. Specifically, multiple recipients from a single donor displayed highly individualised virus colonisation patterns.

CONCLUSIONS

The impact of viruses on long-term microbial dynamics is a factor that should be reviewed when considering FMT as a therapeutic option.

Anatomy of STEM teaching in North American universities

National and local initiatives focused on the transformation of STEM teaching in higher education have multiplied over the last decade. These initiatives often focus on measuring change in instructional practices, but it is difficult to monitor such change without a national picture of STEM educational practices, especially as characterized by common observational instruments. We characterized a snapshot of this landscape by conducting the first large scale observation-based study. We found that lecturing was prominent throughout the undergraduate STEM curriculum, even in classrooms with infrastructure designed to support active learning, indicating that further work is required to reform STEM education. Additionally, we established that STEM faculty’s instructional practices can vary substantially within a course, invalidating the commonly-used teaching evaluations based on a one-time observation.

Although lecture is prominent throughout the undergraduate STEM curriculum, STEM faculty employ varied teaching practices within the same course.

Genetic variation in Pythium myriotylum based on SNP typing and development of a PCR-RFLP detection of isolates recovered from Pythium soft rot ginger

Pythium myriotylum is responsible for severe losses in both capsicum and ginger crops in Australia under different regimes. Intraspecific genomic variation within the pathogen might explain the differences in aggressiveness and pathogenicity on diverse hosts. In this study, whole genome data of four P. myriotylum isolates recovered from three hosts and one Pythium zingiberis isolate were derived and analysed for sequence diversity based on single nucleotide polymorphisms (SNPs). A higher number of true and unique SNPs occurred in P. myriotylum isolates obtained from ginger with symptoms of Pythium soft rot (PSR) in Australia compared to other P. myriotylum isolates. Overall, SNPs were discovered more in the mitochondrial genome than those in the nuclear genome. Among the SNPs, a single substitution from the cytosine (C) to the thymine (T) in the partially sequenced CoxII gene of 14 representatives of PSR P. myriotylum isolates was within a restriction site of HinP1I enzyme which was used in the PCR-RFLP for detection and identification of the isolates without sequencing. The PCR-RFLP was also sensitive to detect PSR P. myriotylum strains from artificially infected ginger without the need for isolation for pure cultures.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study of intraspecific variants of Pythium myriotylum isolates recovered from different hosts and origins based on single nucleotide polymorphism (SNP) genotyping of multiple genes. The SNPs discovered provide valuable makers for detection and identification of P. myriotylum strains initially isolated from Pythium soft rot (PSR) ginger by using PCR-RFLP of the CoxII locus. The PCR-RFLP was also sensitive to detect P. myriotylum directly from PSR ginger sampled from pot trials without the need of isolation for pure cultures.

Thoughtflow: Standards and Tools for Provenance Capture and Workflow Definition to Support Model-Informed Drug Discovery and Development

Pharmacometric analyses are complex and multifactorial. It is essential to check, track, and document the vast amounts of data and metadata that are generated during these analyses (and the relationships between them) in order to comply with regulations, support quality control, auditing, and reporting. It is, however, challenging, tedious, error-prone, and time-consuming, and diverts pharmacometricians from the more useful business of doing science. Automating this process would save time, reduce transcriptional errors, support the retention and transfer of knowledge, encourage good practice, and help ensure that pharmacometric analyses appropriately impact decisions. The ability to document, communicate, and reconstruct a complete pharmacometric analysis using an open standard would have considerable benefits. In this article, the Innovative Medicines Initiative (IMI) Drug Disease Model Resources (DDMoRe) consortium proposes a set of standards to facilitate the capture, storage, and reporting of knowledge (including assumptions and decisions) in the context of model-informed drug discovery and development (MID3), as well as to support reproducibility: "Thoughtflow." A prototype software implementation is provided.

Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba

The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

Pharmacometrics Markup Language (PharmML): Opening New Perspectives for Model Exchange in Drug Development

The lack of a common exchange format for mathematical models in pharmacometrics has been a long-standing problem. Such a format has the potential to increase productivity and analysis quality, simplify the handling of complex workflows, ensure reproducibility of research, and facilitate the reuse of existing model resources. Pharmacometrics Markup Language (PharmML), currently under development by the Drug Disease Model Resources (DDMoRe) consortium, is intended to become an exchange standard in pharmacometrics by providing means to encode models, trial designs, and modeling steps.

Establishing best practices and guidance in population modeling: an experience with an internal population pharmacokinetic analysis guidance

This tutorial describes the development of a population pharmacokinetic (Pop PK) analysis guidance within Pfizer, which strives for improved consistency and efficiency, and a more systematic approach to model building. General recommendations from the Pfizer internal guidance and a suggested workflow for Pop PK model building are discussed. A description is also provided for mechanisms by which conflicting opinions were captured and resolved across the organization to arrive at the final guidance.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e51; doi:10.1038/psp.2013.26; advance online publication 3 July 2013

Herpes simplex virus type 2 incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China

Herpes simplex virus type 2 (HSV-2) can contribute to the spread of HIV. From March 2006 to November 2009, female sex workers (FSWs) in Yunnan, China were recruited into an open cohort study to determine incidence and risk factors for HSV-2 acquisition. Participants were interviewed and tested for HSV-2 and other sexually transmitted infections (STIs) every six months. A multivariate Cox proportional hazards regression model with time-dependent variables was used to measure associations with HSV-2 acquisition. In 3.5 years, 83 incident cases of HSV-2 infection were diagnosed, yielding an overall incidence of 21.9 per 100 person years (PY) (95% confidence interval [CI], 17.8-26.3). Working in higher risk commercial sex venues, current Neisseria gonorrhoeae infection, age of sexual debut <18 years and lack of a regular sex partner were independent factors associated with HSV-2 acquisition. The high incidence of HSV-2 suggests that prevention methods for HIV/STI control are urgently needed.

Dynamics of the HIV epidemic in southern China: sexual and drug-using behaviours among female sex workers and male clients in Yunnan

To examine the HIV/sexually transmitted infection (STI)-related risk behaviours among community-based female sex workers (FSWs) and their clients in Yunnan Province, China, we performed a cross-sectional study of 705 FSWs and 100 male clients. We found that HIV seroprevalence among FSWs was 13.0% and the most prevalent STI was herpes simplex virus type 2 (HSV-2) (71.1%), followed by Chlamydia trachomatis (18.1%) and syphilis (8.8%). The 20% of FSWs who reported injection drug use also reported needle-sharing behaviours in the last three months. Drug-using FSWs had substantially higher HIV and HSV-2 prevalence, serviced more clients and had a longer history of sex work than non-using FSWs. In total, 57.0% of male clients did not consistently use condoms with FSWs, 2.0% reported illicit drug use and 17.0% had STI symptoms in the last year. The dual risk behaviours of drug-using FSWs and clients place them at greater risk of HIV infection. Intervention programmes must adopt comprehensive methods.

Electromagnetic transition rates in 100,101Pd using the Recoil Doppler Shift Technique

The quadrupole deformations for the low-lying states in the transitional nuclei 100,101Pd have been deduced through the measurement of their electric quadrupole transition probabilities using the Recoil Distance Doppler Shift Method. The nuclei were studied using a 268 MeV 80Se beam impinging on a thin, self-supporting 24Mg target. States in 100Pd and 101Pd populated by the four and three neutron evaporation channels respectively, with reaction gamma-rays detected using the SPEEDY gamma-ray detection array. The recoiling nuclei were stopped in a copper foil and gamma-ray coincidence data taken at 10 separate target-stopper distances between 35 μm and 750 μm. The mean-lifetimes for the lowest lying 2+ (in 100Pd) and 15/2- (in 101Pd) states were measured to be 13.3(9) ps and 10.8(8) ps respectively. These data are compared with predictions from nuclear Total Routhian Surface calculations, which are found to agree with the experimentally deduced values to within 10%.

Combining peer discussion with instructor explanation increases student learning from in-class concept questions

Use of in-class concept questions with clickers can transform an instructor-centered "transmissionist" environment to a more learner-centered constructivist classroom. To compare the effectiveness of three different approaches using clickers, pairs of similar questions were used to monitor student understanding in majors' and nonmajors' genetics courses. After answering the first question individually, students participated in peer discussion only, listened to an instructor explanation only, or engaged in peer discussion followed by instructor explanation, before answering a second question individually. Our results show that the combination of peer discussion followed by instructor explanation improved average student performance substantially when compared with either alone. When gains in learning were analyzed for three ability groups of students (weak, medium, and strong, based on overall clicker performance), all groups benefited most from the combination approach, suggesting that peer discussion and instructor explanation are synergistic in helping students. However, this analysis also revealed that, for the nonmajors, the gains of weak performers using the combination approach were only slightly better than their gains using instructor explanation alone. In contrast, the strong performers in both courses were not helped by the instructor-only approach, emphasizing the importance of peer discussion, even among top-performing students.

Towards the development of a Cavendish banana resistant to race 4 of fusarium wilt: gamma irradiation of micropropagated Dwarf Parfitt (Musa spp., AAA group, Cavendish subgroup)

‘Dwarf Parfitt’, an extra-dwarf Cavendish cultivar with resistance to subtropical race 4 Fusarium oxysporum f. sp. cubense (Foc), was gamma irradiated at a dose of 20 Gy and putative mutants were recovered with improved agronomic characteristics. Further screening of putative mutants for improved yield and fruit size, as well as a degree of resistance to fusarium wilt, led to the selection of a line (DPM25) with improved productivity when grown on soils infested with subtropical race 4 Foc. DPM25 was equal to the industry standard, ‘Williams’, in every agronomic trait measured and it consistently showed a lower incidence of fusarium wilt. Further improvement of field resistance to race 4 Foc is needed in DPM25 and further cycles of mutation induction and selection is an option discussed.

Ginger (Zingiber officinale) autotetraploids with improved processing quality produced by an in vitro colchicine treatment

Ginger autotetraploids were produced by immersing shoot tips in a 0.5% w/v colchicine, 2% v/v dimethyl sulfoxide solution for 2 h. Stomatal measurements were used as an early indicator of ploidy differences in culture with mean stomata length of tetraploids (49.2 μm) being significantly larger than the diploid (38.8 µm). Of the 500 shoot tips treated, 2% were characterised as stable autotetraploid lines following field evaluation over several seasons. Results were confirmed with flow cytometry and, of the 7 lines evaluated for distinctness and uniformity, 6 were solid tetraploid mutants and 1 was a periclinal chimera. Significant differences were noted between individual tetraploid lines in terms of shoot length, leaf length, leaf width, size of rhizome sections (knob weight) and fibre content. The solid autotetraploid lines had significantly wider, greener leaves than the diploids, they had significantly fewer but thicker shoots and, although ‘Queensland’ (the diploid parent from which the tetraploids were derived) had a greater total rhizome mass at harvest, its knob size was significantly smaller. From the autotetraploid lines, one line was selected for commercial release as ‘Buderim Gold’. It compared the most favourably with ‘Queensland’ in terms of the aroma/flavour profile and fibre content at early harvest, and had consistently good rhizome yield. More importantly it produced large rhizome sections, resulting in a higher recovery of premium grade confectionery ginger and a more attractive fresh market product.

The physiologic effect of the pneumoperitoneum on radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) is gaining widespread acceptance as a safe and effective method for liver tumor ablation. Complete tumor ablation is essential for the success of the procedure. Multiple modalities have been explored in an effort to increase the size of the lesion created by RFA. The purpose of this study was to determine the physiologic effects of the pneumoperitoneum on RFA lesion size.

METHODS

A total of 32 RFA lesions were created in eight pigs. After the induction of anesthesia, pneumoperitoneums of 2, 12, and 24 mmHg were established sequentially in each animal. After an equilibration period of 2 min, RF was administered with a constant saline-infused (0.9%) needle at 25 W for 3 min. In subsequent and complementary experiments, both before and during RF administration at each intraperitoneal pressure (IPP), Doppler flow was measured by laparoscopic ultrasound in the portal vein and hepatic artery while blood pressure was monitored by a femoral arterial line. The animals were then killed humanely and the livers were harvested. Measurements were taken in three dimensions of the ablated areas, and the volume was calculated. Statistical analyses were performed using analysis of variance (ANOVA) and repeated measures test.

RESULTS

The average volumes of the lesions (in cm3) were 3.1 +/- 1.8, 5.2 +/- 1.7, and 6.7 +/- 3.3 for IPP of 2, 12 and 24 mmHg, respectively; there was a significant difference between the area of lesion at an IPP of 2 mmHg and an IPP of 24 mmHg ( p < 0.05). Blood flow in the portal vein also decreased significantly from 1.8 +/- 0.6, 0.98 +/- 0.5, and 0.43 +/- 0.2 at IPP of 2, 12, and 24 mmHg, respectively ( p < 0.001). Hepatic artery blood flow and peripheral blood pressure did not change significantly in the respective IPP groups.

CONCLUSIONS

This study indicates that the volume of liver ablated by RF can be increased by augmenting the IPP. Our data support the theory that a decrease in portal blood flow results in decreased heat dissipation during RFA. The laparoscopic approach to RFA offers the advantage of allowing control of the IPP, which may result in a larger volume of ablated tissue per treatment than can be achieved with the percutaneous technique. These preliminary data on normal hepatic tissue must be confirmed clinically in the setting of hepatic tumors.

Regulating bone formation via controlled scaffold degradation

It is widely assumed that coupling the degradation rate of polymers used as cell transplantation carriers to the growth rate of the developing tissue will improve its quantity or quality. To test this hypothesis, we developed alginate hydrogels with a range of degradation rates by gamma-irradiating high-molecular-weight alginate to yield polymers of various molecular weights and structures. Decreasing the size of the polymer chains increased the degradation rate in vivo, as measured by implant retrieval rates, masses, and elastic moduli. Rapidly and slowly degrading alginates, covalently modified with RGD-containing peptides to control cell behavior, were then used to investigate the effect of biodegradation rate on bone tissue development in vivo. The more rapidly degrading gels led to dramatic increases in the extent and quality of bone formation. These results indicate that biomaterial degradability is a critical design criterion for achieving optimal tissue regeneration with cell transplantation.

Human coronavirus 229E: receptor binding domain and neutralization by soluble receptor at 37 degrees C

Truncated human coronavirus HCoV-229E spike glycoproteins containing amino acids 407 to 547 bound to purified, soluble virus receptor, human aminopeptidase N (hAPN). Soluble hAPN neutralized the infectivity of HCoV-229E virions at 37 degrees C, but not 4 degrees C. Binding of hAPN may therefore trigger conformational changes in the viral spike protein at 37 degrees C that facilitate virus entry.

In vitro and in vivo efficacy of photofrin and pheophorbide a, a bacteriochlorin, in photodynamic therapy of colonic cancer cells

This study was designed to investigate the efficacy of photodynamic therapy (PDT) in treating colonic cancer in a preclinical study. Photofrin, a porphyrin mixture, and pheophorbide a (Ph a), a bacteriochlorin, were tested on HT29 human colonic tumor cells in culture and xenografted into athymic mice. Their pharmacokinetics were investigated in vitro, and the PDT efficacy at increasing concentrations was determined with proliferative, cytotoxic and apoptotic assessments. The in vivo distribution and pharmacokinetics of these dyes (30 mg/kg, intraperitoneal) were investigated on HT29 tumor-bearing nude mice. The inhibition of tumor growth after a single 100 J/cm2 PDT session was measured by the changes in tumor volume and by histological analysis of tumor necrosis. PDT inhibited HT29 cell growth in culture. The cell photodamage occurred since the time the concentrations of Ph a and Photofrin reached 5.10(-7) M (or 0.3 microg/mL) and 10 microg/mL, respectively. A photosensitizer dose-dependent DNA fragmentation was observed linked to a cleavage of poly(ADP-ribose) polymerase and associated with an increased expression of mutant-type p53 protein. PDT induced a 3-week delay in tumor growth in vivo. The tumor injury was corroborated by histological observation of necrosis 48 h after treatment, with a correlated loss of specific enzyme expression in most of the tumor cells. In conclusion, PDT has the ability to destroy human colonic tumor cells in vitro and in vivo. This tumoricidal effect is likely associated with a p53-independent apoptosis, as HT29 cells express only mutated p53. The current study suggests a preferential use of Photofrin in PDT of colonic cancer because it should be more effective in vivo than Ph a as a consequence of better tumor uptake.

Use of molecular markers to study the effects of environmental impacts on genetic diversity in brown bullhead (Ameirus nebulosus) populations

Conservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis.

Telerobotic laparoscopic cholecystectomy: initial clinical experience with 25 patients

OBJECTIVE

To determine the safety and feasibility of performing telerobotic laparoscopic cholecystectomies. This will serve as a preliminary step toward the integration of computer-rendered three-dimensional preoperative imaging studies of anatomy and pathology onto the patient's own anatomy during surgery.

SUMMARY BACKGROUND DATA

Computer-assisted surgery (CAS) increases the surgeon's dexterity and precision during minimally invasive surgery, especially when using microinstruments. Clinical trials have shown the improved microsurgical precision afforded by CAS in the minimally invasive setting in cardiac and gynecologic surgery. Future applications would allow integration of preoperative data and augmented-reality simulation onto the actual procedure.

METHODS

Beginning in September 1999, CAS was used to perform cholecystectomies on 25 patients at a single medical center in this nonrandomized, prospective study. The operations were performed by one of two surgeons who had previous laboratory experience using the computer interface. The entire dissection was performed by the surgeon, who remained at a distance from the patient but in the same operating room. The operation was evaluated according to time of dissection, time of assembly/disassembly of robot, complications, immediate postoperative course, and short-term follow-up.

RESULTS

Twenty of the 25 patients had symptomatic cholelithiasis, 1 had a gallbladder polyp, and 4 had acute cholecystitis. Twenty-four of the 25 laparoscopic cholecystectomies were successfully completed by CAS. There was one conversion to conventional laparoscopic cholecystectomy. Set-up and takedown of the robotic arms took a median of 18 minutes. The median operative time for dissection and the overall operative time were 25 and 108 minutes, respectively. There were no intraoperative complications. There was one postoperative complication of a suspected pulmonary embolus, which was treated with anticoagulation. All patients were tolerating diet at discharge.

CONCLUSIONS

Laparoscopic cholecystectomy performed by CAS is safe and feasible, with operative times and patient recovery similar to those of conventional laparoscopy. At present, CAS cholecystectomy offers no obvious advantages to patients, but the potential advantages of CAS lie in its ability to convert the surgical act into digitized data. This digitized format can then interface with other forms of digitized data, such as pre- or intraoperative imaging studies, or be transmitted over a distance. This has the potential to revolutionize the way surgery is performed.

[15]crown-5: an unsymmetrical bifacial hydrogen-bond acceptor in crystal engineering

Reaction of [15]crown-5 with erbium nitrate and a range of nickel salts results in the formation of the hydrogen-bonded chain species [Er(NO3)3(H2O)3]. [15]crown-5 H2O (3), [Ni(H2O)6]Br2 [15]crown-5 2H2O (4), [Ni(H2O)6](ClO4)2 x [15]crown-5 2H2O (5), [Ni(H2O)6](NO3)2 [15]crown-5 2H2O (6) and [[Ni(H2O)4]2(muCl)2]Cl2 [15]crown-5 (7). Complexes 3-5 exhibit low symmetry structures with 2-4 unique crown ether molecules, whereas 6 and 7 are more symmetrical. The factors contributing to this behaviour are discussed within the wider context of [15]crown-5 structures in the Cambridge Structural Database.

Quantities and associations of lead, zinc, cadmium, manganese, chromium, nickel, vanadium, and copper in fresh Mississippi delta alluvium and New Orleans alluvial soils

The topic of this study is the effect of anthropogenic metals on the geochemical quality of urban soils. This is accomplished by comparing the metal contents and associations between two alluvial soils of the lower Mississippi River Delta, freshly deposited alluvial parent materials and alluvial soils collected from a nearby urban environment. Fresh alluvium samples (n = 97) were collected from the Bonnet Carré Spillway. The urban alluvial soil samples (n = 4026) were collected from New Orleans and stratified by census tracts (n = 286). The Spillway samples tend to have less Pb and Zn than generally noted for the baseline of natural soils. Except for Mn and V, Spillway alluvium contains significantly less metal than urban soils. For Spillway samples, the median metal content (in microg g(-1)) is 4.7 Pb, 11.1 Zn, 0.7 Cd, 164 Mn, 0.8 Cr, 3.9 Ni, 3.2 V, and 3.9 Cu. For urban soils, the median metal content (in microg g(-1)) is 120 Pb, 130 Zn, 3.2 Cd, 138 Mn, 2.1 Cr, 9.8 Ni, 3.8 V, and 12.7 Cu. Metal associations also differ between Spillway alluvium and urban alluvial soils. Fresh alluvium correlation coefficients between individual metals vary from 0.87 to 0.99 (P < 10(-13)) except for Cr which ranges from 0.57 to 0.68 (P < 10(-7)). The urban soil correlation coefficients for metals and the index value are 0.40-0.98. In urban soils, Pb, Zn, Cr, and Cu are dominant metals and highly associated, with a correlation coefficient ranging from 0.83 to 0.98 (P < 10(-25)). Their strong association justifies the use of GIS to map the integrated soil metal index (sum of the medians of metals by census tract) of New Orleans. Although also positively correlated (0.40-0.68, P < 10(-10)), Cd, Mn, Ni and V differ in their distribution in the city compared to Pb, Zn, Cr and Cu. Overall, significantly higher metal values occur in the inner city and lower values occur in outlying areas. The human health impact of the mixture of metals is not well understood. This study provides empirical data about the mixture and distribution of metals in New Orleans alluvial soils. Given common technical development, especially of traffic flows in cities, similar patterns of soil metals are expected for all US cities and probably international cities as well. Primary prevention of urban metal accumulations is necessary to enhance and sustain the development of urban culture.

A simplified pneumotachometer for the quantitative assessment of velopharyngeal incompetence

By applying pipe flow rate mechanics, the authors have developed a simple and inexpensive device that can measure oral and nasal airflow and pressure quantitatively. It allows clinicians to document objectively the degree of velopharyngeal incompetence and nasal airway obstruction. This device is a modified U-manometer with a Y-connector to a collection bag. This prototype is being used in the authors' cleft palate clinic and they have found it useful in documenting quantitatively the amount of nasal air escape from either nostril with the corresponding pressure and flow. The primary measurement, which is reproducible and reliable, is the product of a cross-sectional area of oronasal communication and the pressure differential between the oral and nasal cavity. With some modifications, this device can be adapted to estimate the size of the oronasal communication.

Genetic transformation of Cavendish banana (Musa spp. AAA group) cv 'Grand Nain' via microprojectile bombardment

 An effective method has been developed for the stable transformation and regeneration of Cavendish banana (Musa spp. AAA group) cv 'Grand Nain' by microprojectile bombardment. Embryogenic cell suspensions were initiated using immature male flowers as the explant. Cells were co-bombarded with the neomycin phosphotransferase (nptII) selectable marker gene under the control of a banana bunchy top virus (BBTV) promoter or the CaMV 35S promoter, and either the β-glucuronidase (uidA) reporter gene or BBTV genes under the control of the maize polyubiquitin promoter. Plants were regenerated, under selection with kanamycin, that were co-transformed with nptII and either the uidA or BBTV genes. Molecular characterisation of transformants demonstrated that the transgenes had been stably integrated into the banana genome.

Hypothesis testing with the similarity index

Multilocus DNA fingerprinting methods have been used extensively to address genetic issues in wildlife populations. Hypotheses concerning population subdivision and differing levels of diversity can be addressed through the use of the similarity index (S), a band-sharing coefficient, and many researchers construct hypothesis tests with S based on the work of Lynch. It is shown in the present study, through mathematical analysis and through simulations, that estimates of the variance of a mean S based on Lynch's work are downwardly biased. An unbiased alternative is presented and mathematically justified. It is shown further, however, that even when the bias in Lynch's estimator is corrected, the estimator is highly imprecise compared with estimates based on an alternative approach such as 'parametric bootstrapping' of allele frequencies. Also discussed are permutation tests and their construction given the interdependence of Ss which share individuals. A simulation illustrates how some published misuses of these tests can lead to incorrect conclusions in hypothesis testing.

Effect of elevated levels of ornithine decarboxylase on cell cycle progression in skin

By crossing TG.AC v-Ha-ras and K6/ODC transgenic mice, we found previously that an activated ras and follicular ornithine decarboxylase (ODC) overexpression cooperate to generate spontaneous tumors in the skin. Cellular proliferation was dramatically increased in the K6/ODC transgenic skin, as evidenced by elevated proliferating cell nuclear antigen and Ki67 expression compared with nontransgenic littermates. Keratinocytes isolated from transgenic skin also displayed increased clonal growth. Paradoxically, expression of the growth inhibition-associated proteins p53, p21Waf1, p27Klp1, and Bax was increased with ODC overexpression in the skin. ODC overexpression did not affect cyclin D/cyclin-dependent kinase 4 (Cdk4)-dependent phosphorylation of retinoblastoma protein but stimulated cyclin E/Cdk2 and cyclin A/Cdk2-associated kinase activity, with minimal effect on the levels of these proteins. Thus, ODC/polyamine-induced activation of cyclin E/Cdk2 and cyclin A/Cdk2-associated kinase activity may cooperate with the ras induction of cyclin D/Cdk4/6-associated retinoblastoma protein phosphorylation to not only stimulate proliferation but ultimately contribute to tumor development.

Genetic diversity of Typha latifolia (Typhaceae) and the impact of pollutants examined with tandem-repetitive DNA probes

Genetic diversity at variable-number-tandem-repeat (VNTR) loci was examined in the common cattail, Typha latifolia (Typhaceae), using three synthetic DNA probes composed of tandemly repeated "core" sequences (GACA, GATA, and GCAC). The principal objectives of this investigation were to determine whether: (1) the previously reported almost complete lack of polymorphism at allozyme loci in this species was indicative of a reduced amount of genetic diversity at VNTR loci as well; (2) VNTR markers were informative about possible clonal propagation; and (3) significant differences in genetic structure of sampling sites were associated with differences in environmental levels of pollutants at those sites. Previously, widespread sampling across the eastern United States, surveying across ten allozyme loci, has detected only two genotypes, involving a difference at a single locus, among 104 populations. In this study, the amount of genetic diversity detected at VNTR loci: (1) among ramets (N = 40; 40 genotypes detected) collected at ∼8-km intervals along a 320-km transect; (2) among ramets (N = 220; 117 genotypes detected) from five study sites separated by 50-3000 m; and (3) even among ramets within each study site [N = 44 per site; from 13 to 34 genotypes detected per site (270 m(2))] exceeds that previously found in those more geographically widespread allozyme surveys. Among the 260 ramets analyzed here, the mean number of bands scored per individual was 48.61 (SD = 2.80). Mean genetic similarity among ramets collected along the 320-km transect was 0.91, which was within the range of mean genetic similarity within the five study sites (range: 0.89-0.95). Among the five study sites, 61% of the samples analyzed appeared to be clonal ramets, with up to 12 clones detected for 44 ramets sampled within a site. Clones grew intermingled and ranged up to 39 m in extent. Permutation tests of genetic similarity revealed significant genetic differentiation between each of the five study sites. Consistent with the previous allozyme studies, T. latifolia was characterized by extremely low genetic variation relative to levels of polymorphism detected at VNTR loci in other plant species. Estimated heterozygosity among ramets along the 320-km transect ranged from 0.11 to 0.13, while that within the five study sites ranged from 0.05 to 0.12. Estimates of F(st) (0.32-0.41) also indicated considerable genetic subdivision among these stands. Significantly higher genetic diversity was detected at the two study sites that chemistry and toxicity data indicate to be the most severely impacted by pollutants. Although this correlation does not establish cause and effect, the results of this study indicate that the analysis of genetic diversity at VNTR loci may be a useful tool for monitoring anthropogenic-induced changes in the genetic structure of natural populations of plants.

The urban environment and children's health: soils as an integrator of lead, zinc, and cadmium in New Orleans, louisiana, U.S.A

Soils are evaluated as a diagnostic tool of environmental conditions that influence health. The samples for this study are urban topsoil (0-2.5 cm depth) samples (n=4026) analyzed for Pb, Zn, and Cd by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The parent materials for New Orleans soils are derived from the Mississippi River, and alluvium from the Bonnet Carré Spillway (n=31) serve as control samples for this study. The urban samples were stratified by census tract (n=286). Blood Pb (BL) levels of children </=6 years were also stratified by census tract and paired with soil Pb (SL) (n=175). A significant association (P=1.2x10(-23)) was found between median BL and median SL. The association was modeled by BL=3.06+0.33 (SL)(0.5) (correlation coefficient=0.69 between the modeled BL and the observed BL and P=3.5x10(-22)). A median SL threshold (>/=310 microgram g(-1) and <310 microgram g(-1)) for higher metal census tracts (HMCTs) and lower metal census tracts (LMCTs), respectively, represents median BL exposures above and below 9 microgram dL(-1). HMCTs and LMCTs were characterized by demographic and socioeconomic data. HMCTs are more likely (P=4. 5x10(-6)) inhabited by Blacks than by Whites. Of 13,803 children </=6 years in HMCTs, 75% are Black and 22% are White, with other making up the remaining 3%. In LMCTs, the Black to White children ratio is 50:50. In HMCTs, socioeconomic indicators for Blacks are depressed compared to Whites. Zn and Cd are potentially phytotoxic in HMCTs. Children exhibit a steep rise in BL at SL <100 microgram g(-1), and empirically, a safe SL for most children is around 80 microgram++ g(-1). SL is a useful diagnostic tool, and curtailing SL may complement primary Pb prevention for children.

Synthesis of α-Vinyl Amino Acids

This chapter presents procedures for the synthesis of α-vinyl amino acids, in which the usual α-proton is replaced by an unsubstituted vinyl group (Fig. 1). The parent member of this family, α-vinylglycine (R≠H), is a natural product (1,2) and acts as a suicide substrate for a number of PLP-dependent enzymes (4-9). Higher members of this family (R≠H) have also been synthesized (10-12). Several including α-vinyl-m-tyrosine (13-15), α-vinyl-DOPA (13-15), α-vinylglutamate (16), α-vinylornithine (17), α-vinyllysine (18), and α-vinylarginine (18) are Trojan horse inhibitors of their cognate amino acid decarboxylases (AADCs). Such (appropriately labeled) AADC inhibitors may also have potential as reagents for positron emission tomography (19). Fig. 1. Generic structure for α-vinyl amino acids.

Characterisation and early detection of an offtype from micropropagated Lady Finger bananas

Summary. An offtype has been identified from micropropagated Lady Finger bananas (Musa spp., AAB group, Pome subgroup) that is characterised by its slow growth and poor bunch size. Bunch weights were approximately 25% those of normal Lady Finger plants and all of the fruit produced was unmarketable. This particular offtype is the most commonly encountered from micropropagated Lady Finger plants and, in 2 instances, blocks of 3000 and 1500 plants were entirely comprised of this single offtype. Detection of offtype plants was possible during establishment and growth of plants in the glasshouse by the presence of chlorotic streaks in the leaves. In more severe cases the streaks coalesced into chlorotic patches that developed thin, necrotic areas that eventually produced holes or splits in the leaves. Symptom expression was not ameliorated by the addition of fertiliser and even though symptoms were similar to severe Ca and B deficiency, both normal and offtype plants had similar levels of these elements in the leaves. The offtype plants were also slow growing in the glasshouse and produced significantly (P<0.05) smaller pseudostems and leaves than normal plants. Offtype plants could be readily detected after 4 weeks deflasking using the presence of chlorotic streaks in the leaves as the main selection criterion. Maximum discrimination was possible between weeks 5–7 and at the 6-leaf stage when all of the offtypes could be detected.

Co-operation between follicular ornithine decarboxylase and v-Ha-ras induces spontaneous papillomas and malignant conversion in transgenic skin

Ornithine decarboxylase (ODC) is aberrantly regulated in tumor cells and results in high basal levels of ODC and polyamines in many epithelial tumors. To determine if elevated ODC/polyamine levels can co-operate with a mutant Ha-ras gene in mouse skin tumorigenesis, double transgenic mice were generated by breeding K6/ODC transgenic mice with TG.AC v-Ha-ras transgenic mice. A K6 keratin promoter drives the ODC transgene in K6/ ODC transgenic mice, which results in elevated ODC/ polyamine levels directed to the outer root sheath cells of hair follicles. TG.AC transgenic mice carry a v-Ha-ras transgene while still retaining two normal c-Ha-ras alleles. Transgenic mice that possess only the K6/ODC or the v-Ha-ras transgene did not develop tumors unless treated with either a carcinogen or a tumor promoter, respectively. However, a high percentage of double transgenic mice possessing both the K6/ODC and v-Ha-ras transgenes developed spontaneous tumors. All tumors were well-differentiated keratoacanthomas, some of which progressed to carcinomas within 2 months. The development and the maintenance of these ODC/ras tumors was ODC-dependent since alpha-difluoromethylornithine (DFMO), a specific ODC inhibitor, prevented the formation and caused the regression of these tumors. These findings indicate that ODC overexpression and an activated Ha-ras are sufficient to produce a high rate of malignant transformation in an animal model. The ODC/ras double transgenic mouse provides a simple in vivo model without the use of chemical carcinogens or tumor promoters in which to test downstream effectors that play a key role in mediating the development of epithelial tumors resulting from the cooperation between ODC and v-Ha-ras.

Induction by alkaloids and phenobarbital of Family 4 Cytochrome P450s in Drosophila: evidence for involvement in host plant utilization

In vertebrates, cytochrome P450s of the CYP2 and CYP3 families play a dominant role in drug metabolism, while in insects members of the CYP6 and CYP28 families have been implicated in metabolism of insecticides and toxic natural plant compounds. A degenerate 3' RACE strategy resulted in the identification of fifteen novel P450s from an alkaloid-resistant species of Drosophila. The strong (17.4-fold) and highly specific induction of a single gene (CYP4D10) by the toxic isoquinoline alkaloids of a commonly utilized host-plant (saguaro cactus) provides the first indication that members of the CYP4 family in insects may play an important role in the maintenance of specific insect-host plant relationships. Strong barbiturate inducibility of CYP4D10 and two other D. mettleri P450 sequences of the CYP4 family was also observed, suggesting a pattern of xenobiotic responsiveness more similar to those of several vertebrate drug-metabolizing enzymes than to putative vertebrate CYP4 homologs.

When a physician harms a patient by a medical error: ethical, legal, and risk-management considerations

Errors that harm patients are infrequently brought to the attention of these patients. The full disclosure of such medical errors is in the best interest of patients because it allows them to understand what has occurred, and to gain appropriate compensation for the harm that they have suffered. Physicians have been given little guidance regarding how to conduct a relationship with the patient after such an injury. We argue that the physician must continue to respect the patient, and communicate honestly with him or her throughout their relationship, even after the patient has been injured. It is painful to admit our errors, especially to those who have been harmed by them. Nevertheless, offering an apology for harming a patient should be considered to be one of the ethical responsibilities of the profession of medicine. Monetary compensation alone is not to be offered as a charitable gesture; rather, it should be accompanied by an apology to demonstrate the responsibility of the physician to the trusting patient. Full and honest disclosure of errors is most consistent with the mutual respect and trust patients expect from their physicians. Clearly, physicians' ethical responsibilities sometimes differ from their legal and risk-management responsibilities.