Climbing and Clinging of Urban Lizards are Differentially Affected by Morphology, Temperature, and Substrate.

Urbanization alters the environment along many dimensions, including changes to structural habitat and thermal regimes. These can present challenges, but may also provide suitable habitat for certain species. Importantly, the functional implications of these habitat shifts can be assessed through the morphology-performance-fitness paradigm, though these relationships are complicated by interactions among habitat choice, other abiotic factors, and morphology across scales (i.e., micromorphology and gross anatomy). The common wall lizard (Podarcis muralis) is one example of a cosmopolitan and successful urban colonizer. Quantifying both shifts in morphology over time and morphology-performance relationships under various ecological contexts can provide insight into the success of species in a novel environment. To examine how morphological variation influences performance, we measured seven gross morphological characteristics and utilized scanning electron microscopy to obtain high-resolution images of a claw from individuals living in established populations in Cincinnati, Ohio, USA. We used a geometric morphometric approach to describe variation in claw shape and then compared the claws of contemporary lizards to those of museum specimens collected approximately 40 years ago, finding that claw morphology has not shifted over this time. We then performed laboratory experiments to measure the clinging and climbing performance of lizards on materials that mimic ecologically relevant substrates. Each individual was tested for climbing performance on two substrates (cork and turf) and clinging performance on three substrates (cork, turf, and sandpaper) and at two temperatures (24ºC and 34ºC). Clinging performance was temperature insensitive, but determined by substrate-specific interactions between body dimensions and claw morphology. Conversely, the main determinant of climbing performance was temperature, though lizards with more elongate claws, as described by the primary axis of variation in claw morphology, climbed faster. Additionally, we found strong evidence for within-individual trade-offs between performance measures such that individuals who are better at clinging are worse at climbing and vice versa. These results elucidate the complex interactions shaping organismal performance in different contexts and may provide insight into how certain species are able to colonize novel urban environments.

Prevalence of HIV-1 transmitted drug resistance in the incarcerated population.

OBJECTIVES: The aim of the study was to determine the prevalence of transmitted drug resistance (TDR)-associated mutations among treatment-naïve, incarcerated individuals with HIV-1 infection in the USA as well as the class TDR and antiretroviral (ARV) mutations present at baseline. METHODS: Patients over the age of 18 years were included in the study if they had been diagnosed with HIV infection, if their HIV infection was managed through telemedicine and if they were incarcerated in the State of Illinois Department of Corrections between 10 July 2010 and 29 April 2016. Additionally, the patients were required to have a documented genotype and be ARV-naïve. A medical chart review was conducted to assess demographic information, disease burden, and risk factors for acquiring the virus. RESULTS: The inclusion criteria were met for 105 patients. A total of 24 patients (23%) had a clinically significant mutation associated with resistance to any drug class. The prevalence of mutations conferring clinically significant resistance was 19% for nonnucleoside reverse transcriptase inhibitors (NNRTIs), 18% for nucleoside reverse transcriptase inhibitors (NRTIs), and 4% for protease inhibitors (PIs). Five per cent of patients had dual-class TDR to both NRTI and NNRTI drug classes and 2% of patients had mutations to both NNRTI and PI drug classes. There was no significant increase in the prevalence of clinically relevant drug resistance mutations based on demographics, burden of disease, or risk factors for acquiring the virus. CONCLUSIONS: A high prevalence of TDR was identified in the ARV-naïve incarcerated population. The results of this study indicate an increased prevalence of TDR in a largely unstudied incarcerated population, demonstrating the need for increased monitoring of resistance in HIV-infected patients world-wide.

Co-administration of elvitegravir/cobicistat/tenofovir disoproxil fumarate/emtricitabine and atazanavir in treatment-experienced HIV patients.

We report the use of elvitegravir 150 mg/cobicistat 150 mg/tenofovir disoproxil fumarate 300 mg/emtricitabine 200 mg (EVG/COBI/TDF/FTC) once daily, in addition to once-daily atazanavir (ATV) 300 mg, in treatment-experienced patients with human immunodeficiency virus (HIV). Due to limited data available on the co-administration of these agents, our objective was to evaluate and monitor safety and efficacy of this regimen in patients who developed resistance or intolerance to conventional antiretroviral therapy (ART). This short report included offenders incarcerated in the Illinois Department of Corrections who were ≥18 years, HIV-infected, had documented antiretroviral resistance, and received EVG/COBI/TDF/FTC + ATV once daily. Based on previous ART, resistance patterns and current medications, seven patients were initiated on once-daily therapy consisting of EVG/COBI/TDF/FTC and ATV. Due to extensive resistance, two of the seven patients were also started on abacavir (ABC) 600 mg daily in addition to EVG/COBI/TDF/FTC and ATV. Of the seven patients, one had ART changed due to concerns of resistance based on a genotype, one experienced a decline in renal function that warranted a change in therapy, and one is currently virologically suppressed on a combination of EVG/COBI/TDF/FTC, ATV, and ABC. The remaining four patients remain virologically suppressed on EVG/COBI/TDF/FTC + ATV. Therapy consisting of EVG/COBI/TDF/FTC and ATV may be a viable option for some treatment-experienced HIV-infected patients. Further studies evaluating the safety, efficacy, and pharmacokinetics of this therapy are warranted, given the lack of information currently available.

SPE-MS analysis of absorption, distribution, metabolism and excretion assays: a tool to increase throughput and steamline workflow.

In an effort to create faster and more efficient bioanalytical methods for drug development, many investigators have evaluated a variety of SPE-MS systems. Over the past 15 years online systems have evolved from run times of >1.5 min/sample to <10 s/sample. High-throughput SPE-MS methods for in vitro absorption, distribution, metabolism and excretion screening assays have been described by several laboratories and shown to produce results comparable to conventional LC-MS/MS systems. While quantitative analysis of small molecules in biological matrixes holds many challenges, for several applications SPE-MS methods have achieved comparable results to LC-MS/MS with the benefit of 10-30-times the throughput. Based on its distinct advantages of throughput and streamlined workflow efficiencies, SPE-MS is a useful tool for the analysis of many in vitro absorption, distribution, metabolism and excretion assays and in vivo bioanalytical studies. Further development of SPE-MS methods and analysis workflows has the potential to expand the capabilities of this technology for other challenging bioanalytical applications.

Evaluation of a high-throughput online solid phase extraction-tandem mass spectrometry system for in vivo bioanalytical studies.

High throughput-solid phase extraction tandem mass spectrometry (HT-SPE/MS) is a fully automated system that integrates sample preparation using ultrafast online solid phase extraction (SPE) with mass spectrometry detection. HT-SPE/MS is capable of conducting analysis at a speed of 5-10 s per sample, which is several fold faster than chromatographically based liquid chromatography-mass spectrometry (LC-MS). Its existing applications mostly involve in vitro studies such as high-throughput therapeutic target screening, CYP450 inhibition, and transporter evaluations. In the current work, the feasibility of utilizing HT-SPE/MS for analysis of in vivo preclinical and clinical samples was evaluated for the first time. Critical bioanalytical parameters, such as ionization suppression and carry-over, were systematically investigated for structurally diverse compounds using generic SPE operating conditions. Quantitation data obtained from HT-SPE/MS was compared with those from LC-MS analysis to evaluate its performance. Ionization suppression was prevalent for the test compounds, but it could be effectively managed by using a stable isotope labeled internal standard (IS). A structural analogue IS also generated data comparable to the LC-MS system for a test compound, indicating matrix effects were also compensated for to some extent. Carry-over was found to be minimal for some compounds and variable for others and could generally be overcome by inserting matrix blanks without sacrificing assay efficiency due to the ultrafast analysis speed. Quantitation data for test compounds obtained from HT-SPE/MS were found to correlate well with those from conventional LC-MS. Comparable accuracy, precision, linearity, and sensitivity were achieved with analysis speeds 20-30-fold higher. The presence of a stable metabolite in the samples showed no impact on parent quantitation for a test compound. In comparison, labile metabolites could potentially cause overestimation of the parent concentration if the ion source conditions are not optimized to minimize in-source breakdown. However, with the use of conditions that minimized in-source conversion, accurate measurement of the parent was achieved. Overall, HT-SPE/MS exhibited significant potential for high-throughput in vivo bioanalysis.

Cytochrome P450 fluorometric substrates: identification of isoform-selective probes for rat CYP2D2 and human CYP3A4.

We have tested a panel of 29 cDNA-expressed rat and human enzymes with 9 fluorometric substrates to determine the P450 isoform selectivity in the catalysis of the substrates to fluorescent products. The substrates examined were dibenzyl fluorescein, 7-benzyloxyquinoline (BQ), 3-cyano-7-ethoxycoumarin, 3-cyano-7-methoxycoumarin, 7-methoxy-4-trifluoromethylcoumarin, 3-[2-(N,N-diethyl-N-methylamino)ethyl]-7-methoxy-4-methylcoumarin (AMMC), 3-[2-(N,N-diethyl-N-methylamino)ethyl]-7-methoxy-4-trifluoromethylcoumarin, 7-benzyloxyresorufin, and 7-benzyloxy-4-trifluoromethylcoumarin (BFC). For most substrates, multiple cDNA-expressed cytochrome P450 isoforms were found to catalyze the formation of the fluorescent product. However, among the combinations tested, rat CYP2D2 displayed high selectivity for AMMC demethylation (a substrate selective for CYP2D6 in human liver microsomes). AMMC demethylation activity was 15-fold lower in microsomes isolated from female Dark Agouti rats, a model known to have a low abundance of CYP2D2, and apparent K(M) values were similar for cDNA-expressed CYP2D2 and male Sprague-Dawley liver microsomes. BFC dealkylation and BQ dealkylation were selective but not exclusive for human CYP3A4. A small role for CYP1A2 could be demonstrated. The CYP3A4 selectivity in hepatic microsomes was supported by studies using chemical and antibody inhibitors and a correlation analysis within a panel of liver microsomes from individual donors. BQ demonstrated a higher degree of selectivity for and higher rates of metabolism by CYP3A than BFC. However, per unit enzyme the fluorescent signal is lower for BQ than BFC. AMMC, BQ, and BFC should find uses as enzyme-selective probe substrates.

Impact of endovascular repair for abdominal aortic aneurysms in octogenarians.

A total of 50 consecutive patients (86% male; median age, 82 years) underwent endovascular repair of abdominal aortic aneurysms (AAAs) ranging from 4.0 to 9.0 cm (median, 5.2 cm). Efficacy of aneurysm exclusion was assessed by angiography, duplex scan, and/or contrast-enhanced computed tomography (CT). Acute technical success was 82%. Access failed in one patient, and immediate conversion to open operation was required in two patients. Improper deployment of the endoluminal graft (ELG) across the renal arteries occurred in one patient. The median operation time, estimated blood loss, packed red blood cells received, contrast volume, and length of intensive care and hospital stay were 128 min, 200 mL, 0.1 unit, 297 mL, 0.9 days, and 3 days, respectively. ELG limb thrombosis was seen in one patient. There were 4 (8%) early endoleaks, and 2 endoleaks were discovered in other patients at 3 and 6 months. Local/vascular and remote/systemic postoperative complications were seen in 13 (26%) and 9 (18%) patients, respectively. At a median follow-up of 11 months (range 2 to 36 months), clinical success was 78%. The aneurysm sac diameter (n = 49) decreased from a preoperative median of 5.2 to 4.7 cm (p = 0.0001). Technical success was high, and results at 11 months were satisfactory. Long-term outcomes require further study.

Transrenal fixation of aortic endografts: intermediate follow-up of a single-center experience.

PURPOSE: To examine the fate of the renal ostia following transrenal fixation of endovascular aortic stent-grafts. METHODS: Thirty-five patients (29 men; mean age 75 years) undergoing endovascular repair for abdominal aortic aneurysms (AAAs) had transrenal fixation of the uncovered proximal stent due to a short (< 1.5 cm long) or conical neck or a periprocedural endoleak. Eighteen (51%) patients were hypertensive; 7 (20%) had renal artery stenoses (RAS). Outcome measures included blood pressure, serum creatinine, computed tomography, and renal artery duplex scans. RESULTS: Two patients with > or = 60% RAS had renal stents placed during the endograft procedure; the other 5 RAS patients were normotensive and their renal lesions were not treated. Overall technical success was 82.9% (29/35). One (2.9%) case was converted due to graft twisting. There were 5 (14.2%) early endoleaks. Transient postoperative creatinine elevations were observed in 5 (14.2%) cases. Over a median 11-month period (range 2-24), no secondary endoleaks or silent renal artery occlusions were seen. One normotensive patient with an untreated > or = 60% renal lesion developed hypertension and severe stenosis (99%) at 4 months; stenting through the interstices of the transrenal stent was performed. No disease progression was seen in the other 6 RAS patients. CONCLUSIONS: In the intermediate period, transrenal fixation appears to have no adverse effects on renal blood flow. Moreover, in patients with no evidence of renal disease or preoperative RAS < 60%, it does not precipitate or cause progression of renal stenosis. However, patients with preoperatively documented RAS > or = 60% are a concern and mandate further study.

Intraoperative subclavian artery stenting to salvage a LIMA graft.

The internal mammary artery is the preferred conduit for coronary bypass grafting; however, suboptimal flow through the internal mammary artery is sometimes found during the operation, and the conduit is abandoned. Subclavian artery stenosis, a well-recognized cause of reduced internal mammary artery flow, is easily and effectively treated with endovascular techniques. We describe a case of intraoperative primary stent deployment in a high-grade subclavian artery stenosis compromising internal mammary artery flow.

Production of recombinant hydroxylated human type III collagen fragment in Saccharomyces cerevisiae.

A recombinant hydroxylated fragment of human type III collagen has been produced in Saccharomyces cerevisiae by coordinated coexpression of a collagen gene fragment together with both the alpha- and beta-subunit genes for prolyl-4-hydroxylase (EC 1.14.11.2). The collagen fragment consisted of 255 residues of the helical domain and the complete C-telopeptide and C-propeptide domains. It was inserted under the control of the ethanol-inducible ADH2 promoter in a multicopy, TRP1-selectable, yeast expression vector, YEpFlag1. The prolyihydroxylase subunit genes were cloned on either side of a bidirectional galactose-inducible promoter in a low-copy minichromosome yeast expression vector, pYEUra3, which is URA3 selectable. Coordinated expression of the three different gene products after cotransformation into S. cerevisiae was detected by immunoblotting. Amino acid analysis of an immunoreactive collagen fraction demonstrated the presence of hydroxyproline, while the presence of a triple-helical domain in the collagen fragment was demonstrated by its resistance to pepsin proteolysis.

Tissue response to biomaterials used for staple-line reinforcement in lung resection: a comparison between expanded polytetrafluoroethylene and bovine pericardium.

OBJECTIVE: A study in a canine model of lung-reduction surgery evaluated the tissue response to polytetrafluoroethylene (ePTFE) and bovine pericardium (BP) used for staple-line reinforcement. METHODS: In each of ten dogs, BP was placed in one lung and ePTFE in the other. The implants were retrieved at 30, 95, or 167 days after implantation and studied histologically. The connective tissue covering the implants was measured and analysis of variance was used to compare results with the two materials. RESULTS: At 30 days, the BP specimens showed focal chronic inflammation and thin tissue coverage, whereas the ePTFE specimens had no focal inflammation and thick tissue coverage. At 95 and 167 days, the inflammation in the BP specimens had resolved, but tissue coverage remained minimal, and there was no resorption of the BP. In the ePTFE specimens, tissue coverage had increased. Analysis of variance comparing representative tissue specimens showed that the tissue encapsulating the ePTFE was significantly thicker than that surrounding the BP (P < 0.0001). No air leaks, staple-line disruptions, or infections occurred in the study. CONCLUSIONS: Neither ePTFE nor BP is resorbable. Both materials have been used successfully, without resultant infections, for clinical staple-line reinforcement. The more favorable tissue response to ePTFE observed in this study may have clinical ramifications. Comparative clinical studies of the two materials are needed.

Prevention of air leaks after pulmonary wedge resection.

Prolonged air leak after a lung volume reduction operation for pulmonary emphysema is a major cause of morbidity and prolonged hospital stay. Staple line reinforcement is recognized as an effective adjunctive technique for decreasing the occurrence of air leaks after pulmonary wedge resection. Numerous materials have been used for staple-line reinforcement. We use expanded polytetrafluoroethylene sleeves that fit over the arms of surgical staplers to facilitate staple-line reinforcement in both thoracoscopic and open lung volume reduction procedures. The expanded polytetrafluoroethylene sleeves do not require rinsing or special handling; they are easy to use and effective in preventing air leaks. We had no prolonged air leaks or infections in any of the cases in which we used the sleeves.

Comparison of continuous infusion of fentanyl to bolus dosing in neonates after surgery.

OBJECTIVE: Concern about respiratory depression may lead to underuse of postoperative narcotic analgesia in neonates. The authors compared continuous infusion of fentanyl with bolus dosing in infants after surgery to determine whether continuous infusion is associated with less respiratory depression. STUDY DESIGN: In the first phase of the study, 16 patients were randomly assigned to receive fentanyl by continuous infusion (C) or bolus dosing every 2 hours (B) in a double-blinded trial. Respiratory events were recorded. An observational pain score and saliva for cortisol concentration were obtained 2, 8, and 24 hours after beginning treatment to compare efficacy of pain control. In the second phase, 20 additional patients received fentanyl by continuous infusion in an unblinded fashion, with the same data collection, to more accurately determine the incidence of respiratory events. RESULTS: In phase 1, apnea occurred in eight of nine B patients (89%) compared with one of seven C patients (14%; P < .009), prompting termination of the randomized trial. The incidence of apnea or significant respiratory depression in the next 20 patients (phase 2) who received fentanyl by continuous infusion was 25% (5 of 20; P < .01 v B). Episodes of apnea in B patients required significantly more intervention than episodes in C patients (P < .01). However, in phase 2, more patients remained intubated and ventilated than in phase 1. Pain scores and salivary cortisol concentrations decreased over the 24-hour study period and were similar in B and C patients during both phases of the study. CONCLUSION: Continuous infusion of fentanyl at the doses studied is associated with pain control similar to that with bolus dosing at regular intervals. Although episodes of respiratory depression were less severe and less frequent for C patients, there may be an increased need for ventilator support with continuous infusion of fentanyl to achieve acceptable pain control. Providing adequate pain control to neonates in the immediate postoperative period remains a challenge.

Management of cecal perforation secondary to Ogilvie's syndrome by laparoscopic tube cecostomy.

Acute pseudoobstruction of the colon (Ogilvie's syndrome) rarely leads to perforation of the colon. A case of such a perforation is described that was successfully managed laparoscopically with tube cecostomy.

Glutamine-glutamate exchange between placenta and fetal liver.

The hypothesis that glutamine shuttles nitrogen between placenta and fetal liver via interconversion with glutamate was explored by infusing L-[1,2-13C2]glutamine in six fetal sheep chronically catheterized for sampling of the umbilical and hepatic circulations. Fetal plasma glutamine disposal rate was 19.9 +/- 1.3 mumol.min-1.kg fetus-1. Entry of glutamine from the placenta accounted for approximately 60% of the total glutamine entry rate in fetal plasma. Glutamine was taken up by fetal liver, and 45.3 +/- 7.9% of the glutamine taken up was released as glutamate. The fetal liver released large quantities of glutamate, as evidenced by a sixfold increase in plasma glutamate concentration in the blood flowing through the left hepatic lobe and a hepatic glutamate output-to-O2 uptake molar ratio of 0.149 +/- 0.013. In conjunction with a previous study of fetal glutamate metabolism, these data demonstrate that glutamine entering the fetal circulation is converted to glutamate by the fetal liver at a rate of approximately 3-4 mumol.min-1.kg fetus-1.

Glutamate metabolism in fetus and placenta of late-gestation sheep.

Glutamate is produced by the fetal liver and taken up by the placenta. To explore the functional meaning of this exchange, the disposal rate (DR), clearance, conversion to glutamine, and decarboxylation rate of fetal plasma glutamate were studied at 129 +/- 2 days of gestation in seven fetal lambs infused via a systemic vein with L-[2,3,3,4,4-2H5]glutamate and L-[1-14C]glutamate. In two experiments, L-[1-13C]glutamate was also infused. The mean glutamate DR and clearance were 11.9 +/- 1.3 mumol.min-1.kg-1 and 200 +/- 8 ml.min-1.kg-1, respectively. The placenta extracted 88.5 +/- 0.8% of the tracer glutamate carried by the umbilical circulation and contributed to 61.3 +/- 3.2% of the glutamate DR. Most of the 14C infused as L-[1-14C]glutamate was converted to 14CO2: 37 +/- 4% by the fetus and 41 +/- 6% by the placenta. Of the labeled glutamate taken up by the placenta, 6.2 +/- 1.5% was returned to the fetus as glutamine. The glutamine-to-glutamate enrichment ratio in fetal arterial plasma was 0.066 +/- 0.008. We conclude that fetal plasma glutamate has an exceptionally high clearance because the flux of glutamate into the placenta is virtually equal to umbilical glutamate delivery rate. The main pathway of fetal plasma glutamate disposal is oxidation by placental and fetal tissues. Placental conversion of glutamate to fetal glutamine is a relatively small component of the placental metabolism of fetal glutamate.

Clinical evaluation of an acetaminophen meter for the rapid diagnosis of acetaminophen intoxication.

STUDY OBJECTIVES: To test the accuracy of a newly developed meter that determines serum acetaminophen concentration after a 30-second analysis of one drop of whole blood. DESIGN: Sixty-six blood samples from patients with known or suspected drug overdose were analyzed for the presence of acetaminophen. In all cases determination of serum acetaminophen concentration was performed simultaneously with the meter and by a reference laboratory. SETTING: Eligible patients were those who presented during a nine-month period to the emergency departments of two tertiary care hospitals (including a pediatric hospital). RESULTS: Thirty-one specimens had a laboratory-confirmed detectable acetaminophen concentration. The meter identified these toxic specimens in all cases; there were no false-negatives (sensitivity, 100%). Among the 35 specimens not containing acetaminophen, the meter invariably confirmed a nondetectable serum acetaminophen concentration (specificity, 100%). Acetaminophen measurements by the meter correlated strongly with laboratory determinations (r = .985, P less than .001). Repeated testing of one specimen documented the precision and reproducibility of the meter's analysis; mean coefficient of variation was .08 in measuring toxic acetaminophen concentrations. Drug coingestion had no significant effect on the accuracy of the meter. Instrument accuracy was maintained after more than 100 uses without recalibration. CONCLUSIONS: This meter identifies the possibility of rapid and accurate determinations of serum acetaminophen concentration. The instrument is ideally suited for patients with acetaminophen poisoning in whom expeditious and appropriate administration of antidotal therapy is desired.