A Randomized, Double Blind Study to Evaluate the Efficacy of Palonosetron with Dexamethasone Versus Palonosetron Alone for Prevention of Post-Operative Nausea and Vomiting in Subjects Undergoing Bariatric Surgeries with High Emetogenic Risk

Introduction:

Postoperative (PONV) and postdischarge (PDNV) nausea and vomiting are common (60-70%) after bariatric surgery. Palonosetron (Pal), a novel 5-HT3 antagonist, is an effective antiemetic with a prolonged duration of action in the setting of PDNV. We hypothesized that combination therapy with Palonosetron (Pal) and dexamethasone (Dex) would improve treatment in comparison to Palonosetron alone in patients at high risk for PONV.

Methods:

In this study, patients undergoing bariatric laparoscopic surgery under general anesthesia, a subgroup of a larger Phase IV clinical trial of patients who had laparoscopic surgery, were randomized to 8 mg Dex + 0.075mg Pal or saline + 0.075mg Pal. Data was collected postoperatively at 2, 6, 24 and 72 hrs. A Functional Living Index-Emesis (QOL-FLIE) test was administered at 96 hrs.

Results:

We enrolled 76 ASA 1-2 patients with at least 3 PONV risk factors. Both randomization groups had a low incidence of vomiting in the PACU (Pal, 0.0%; Pal + Dex, 5.4%) as well as at 72 hours (0.0% both groups). Complete response (no vomiting, no rescue medication) was not different between treatment groups at any time intervals. Cumulative success rates over the entire 72 hrs were 60.4% (Pal alone) vs. 60.0% (Pal + Dex). Nausea scores (4 point ordinal scale) were not different between groups for any time intervals. Cumulative success scores for nausea (score = “none”; 0-72 hrs) were 41.9% for the Pal group, and 55.2% for the Pal+ Dex group. The Pal + Dex group showed a trend toward greater satisfaction on the QOL-FLIE scores with the greatest differences in the “nausea domain”.

Discussion:

The combination therapy (Pal + Dex) did not significantly reduce the incidence of PONV or PDNV when compared with Pal alone although a trend was observed indicating the possible increased efficacy of multi-drug therapy. There was no change in comparative efficacy over 72 hrs, possibly due to the low incidence of PDNV in both groups.

Repair of a palmar soft tissue defect of the proximal interphalangeal joint with a transposition flap from the dorsum of the proximal phalanx

This article describes the use of a transposition flap raised from the dorsum of the proximal phalanx for coverage of the volar defects at the proximal interphalangeal joint. The flap was based on the first dorsal branch of the proper digital artery. From January 2007 to March 2009, 14 digits in 14 patients (10 males and 4 females) were treated. There were 5 index, 6 middle, 2 ring, and 1 little finger. All patients underwent surgery 2-9 hours (mean 5 hours) after injury. Soft tissue defects ranged in size from 1.2 × 1.7 cm to 2.1 × 2.3 cm (mean 1.7 × 2 cm). Flap size ranged from 1.5 × 1.7 cm to 2.4 × 2.7 cm (mean 2 × 2.4 cm). Mean pedicle length was 1.1 cm (range 0.8-1.4 cm). All flaps completely survived. At final follow-up from 24-29 months (mean 26 months), mean active motion arcs of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints were 84° (range 75-91°), 86° (range 65-100°) and 54° (range 32-80°), respectively. Our technique is useful and reliable for coverage of a palmar defect over the proximal interphalangeal joint.

Laser hosing in relativistically hot plasmas

Electron response in an intense laser is studied in the regime where the electron temperature is relativistic. Equations for laser envelope and plasma density evolution, both in the electron plasma wave and ion acoustic wave regimes, are rederived from the relativistic fluid equations to include relativistic plasma temperature effect. These equations are used to study short-pulse and long-pulse laser hosing instabilities using a variational method approach. The analysis shows that relativistic electron temperatures reduce the hosing growth rates and shift the fastest-growing modes to longer wavelengths. These results resolve a long-standing discrepancy between previous nonrelativistic theory and simulations or experiments on hosing.

CT-guided percutaneous chemoablation using an ethanol-ethiodol-doxorubicin emulsion for the treatment of metastatic lymph node carcinoma: a comparative study

Current therapies for metastatic lymph node (LN) are a major burden on health-care systems. Alternative such as percutaneous chemoablation using interstitial injection of ethanol or ethanol-ethiodol-drug(s) mixture (EEM) has been successfully applied to solid tumor ablation of the liver, adrenal glands, lymph nodes and others. However, EEM chemoablation efficacy on two most frequent clinical lymph node presentation, isolated or confluent, has not yet been determined. This study was designed to compare the therapeutic effects of CT-guided percutaneous EEM injection (PEEMI) on patients presenting with single or multiple confluent metastatic LN localizations from various carcinoma. Thirty six patients with metastatic LN carcinoma at various anatomical regions were enrolled from 2009 to 2010 over a nine month period. They were separated into two groups: group A includes 24 single isolated metastatic lymph nodes and group B includes 12 multiple and confluent nodes. The primary end point was the ablative efficacy of PEEMI. The intratumoral (IT) EEM distribution and the occurrence of reflux were recorded. Adjuvant systemic chemotherapy was administered after the procedure. Contrast-enhanced CT scans were performed during procedure and follow-up. Six patients were tested for Fluorodeoxyglucose (FDG) fixation before and after the procedure. For group A the EEM IT distribution-to-tumor ratio was 100% vs. 50% to 80% for group B (t = 11.5, p < 0.05). The reflux frequency was 80% for group A versus 30% for group B. For group A, a complete response (CR) rates of 45.8%, 70.8%, 91.7% and a partial response (PR) rates of 54.2%, 29.2%, 8.3% were obtained at 3, 6 and 12 months after therapy. Regarding group B, a CR rate of 0%, 0%, 0% and PR rate of 16.7%, 50%, 58.3% were observed at similar period of time. Standardized rate by direct method was performed and the CR rate (74.5%) for group A was higher than for group B. The tumor FDG uptake was lower 6 months after PEEMII compared with the preoperative images. Five patients presenting with concomitant lung metastasis, had a good local response-node size reduction on postoperative CT scanning, but no response on lung nodules that were progressing. No serious adverse events were observed. A few patients had mild pain during the procedure, which resolved with peritumor injection of local anesthetic. No needle tract seeding or infection occurred. CT-guided PEEMI treatment is a simple, fast and predictable procedure that has better effectiveness on single, well circumscribed metastatic lymph node than on multiple and confluent ones. Technical improvements are expected to bring better results on large nodes that should be confirmed on larger group of patients.

Generating energetic electrons through staged acceleration in the two-plasmon-decay instability in inertial confinement fusion

A new hot-electron generation mechanism in two-plasmon-decay instabilities is described based on a series of 2D, long-term (~10 ps) particle-in-cell and fluid simulations under parameters relevant to inertial confinement fusion. The simulations show that significant laser absorption and hot-electron generation occur in the nonlinear stage. The hot electrons are stage accelerated from the low-density region to the high-density region. New modes with small phase velocities develop in the low-density region in the nonlinear stage and form the first stage for electron acceleration. Electron-ion collisions are shown to significantly reduce the efficiency of this acceleration mechanism.

Mechanism of generating fast electrons by an intense laser at a steep overdense interface

The acceleration and heating of electrons by an intense laser normally incident on a steep overdense plasma interface is investigated using the particle-in-cell code osiris. Energetic electrons are generated by the laser's electric field in the vacuum region within λ/4 of the surface. Only those electrons which originate within the plasma with a sufficiently large transverse momentum can escape the plasma. This mechanism relies on the standing wave structure created by the incoming and reflected wave and is therefore very different for linear and circularly polarized light.

Differential enamel and osteogenic gene expression profiles in odontogenic tumors

Odontogenic tumors occur within the jaw bones and may be derived from odontogenic epithelium or ectomesenchyme or contain active components of both tissue types. We investigated the gene expression profile of enamel matrix proteins (EMPs), genes related to osteogenesis, and the mineralization process in odontogenic tumor cell populations focusing on an ameloblastoma (AB-1), a keratocystic odontogenic tumor (KCOT-1), and a calcifying epithelial odontogenic tumor (CEOT-1). All cell populations were shown to be epithelial in origin by CK14 expression. All tested EMPs were expressed by all odontogenic tumor cell types, with higher transcript levels seen in the AB-1 population especially for AMEL, AMBN, and ODAM. CEOT-1 cell populations showed a greater content of ALP-positive cells as well as higher ALP mRNA levels. Using qRT-PCR, we found a higher expression of 8 genes in the CEOT-1 compared to the AB-1 and KCOT-1. In this study we demonstrated the establishment of AB-1, KCOT-1 and CEOT-1 cell populations. The unique gene expression profiles of AB-1, KCOT-1, and CEOT-1 cells and their interactions with the surrounding microenvironment may support their unique tumor development, progression, and survival.

Lipid and endothelium-related genes, ambient particulate matter, and heart rate variability--the VA Normative Aging Study

BACKGROUND

Many studies have shown that exposures to air pollution are associated with cardiovascular events, although the mechanism remains to be clarified. To identify whether exposures to ambient particles act on autonomic function via the lipid/endothelial metabolism pathway, whether effects of particulate matter <2.5 mum in aerodynamic diameter (PM(2.5)) on heart rate variability (HRV) were modified by gene polymorphisms related to those pathways were evaluated.

METHODS

HRV and gene data from the Normative Aging Study and PM(2.5) from a monitor located a kilometre from the examination site were used. A mixed model was fitted to investigate the associations between PM(2.5) and repeated measurements of HRV by gene polymorphisms of apolipoprotein E (APOE), lipoprotein lipase (LPL) and vascular endothelial growth factor (VEGF) adjusting for potential confounders chosen a priori.

RESULTS

A 10 microg/m(3) increase in PM(2.5) in the 2 days before the examination was associated with 3.8% (95% CI 0.2% to 7.4%), 7.8% (95 CI 0.4% to 15.3%) and 10.6% (95% CI 1.8% to 19.4%) decreases of the standard deviation of normal-to-normal intervals, the low frequency and the high frequency, respectively. Overall, carriers of wild-type APOE, LPL and VEGF genes had stronger effects of particles on HRV than those with hetero- or homozygous types. Variations of LPL-N291S, LPL-D9N and APOE-G113C significantly modified effects of PM(2.5) on HRV.

CONCLUSION

Associations between PM(2.5) and HRV were modified by gene polymorphisms of APOE, LPL and VEGF; the biological metabolism remains to be identified.

Anisotropic structure of the order parameter in FeSe(0.45)Te(0.55) revealed by angle-resolved specific heat

The central issues for understanding iron (Fe)-based superconductors are the symmetry and structure of the superconducting gap. So far the experimental data and theoretical models have been highly controversial. Some experiments favor two or more constant or nearly constant gaps, others indicate strong anisotropy and yet others suggest gap zeros ('nodes'). A unique method for addressing this issue, and one of very few methods that are bulk and angle resolved, is measuring the electronic-specific heat in a rotating magnetic field. In this study, we present the first such measurement for an Fe-based high-T(c) superconductor. We observed a fourfold oscillation of the specific heat as a function of the in-plane magnetic field direction. Our results are consistent with the expectations for an extended s-wave model, with a significant gap anisotropy on the electron pockets and the gap minima along the ΓM (Fe-Fe bond) direction.

Plasma thermal effect on the relativistic current-filamentation and two-stream instabilities in a hot-beam warm-plasma system

Based on fully kinetic model using drift-Maxwellian distributions and taking into account the transverse electrostatic field (TEF), it is shown that the current-filamentation instability (CFI) grows unexpectedly with the plasma temperature. The growth is attributed to the decreasing of the TEF as the plasma becomes hot. In the low-temperature plasma regime where the TEF is strong, it is identified that the TEF can dominate over the thermal pressure in suppressing the CFI. Since the TEF originates from the temperature difference between the beam and the plasma, the plasma temperature plays a significant role for the development of the CFI and the quasistatic magnetic fields in a hot-beam warm-plasma system. Particle-in-cell simulations verify the above results.

Growth and saturation of convective modes of the two-plasmon decay instability in inertial confinement fusion

Particle-in-cell (PIC) and fluid simulations of two-plasmon decay (TPD) instability under conditions relevant to inertial confinement fusion show the importance of convective modes. Growing at the lower density region, the convective modes can cause pump depletion and are energetically dominant in the nonlinear stage. The PIC simulations show that TPD saturates due to ion density fluctuations, which can turn off TPD by raising the instability threshold through mode coupling.

Relativistic collisional current-filamentation instability and two-stream instability in dense plasma

The collisional effects on the current-filamentation instability (CFI) and the two-stream instability (TSI), which appear as a relativistic intense electron beam penetrating into a cold dense plasma, are investigated. It is shown that the growth rate of the CFI mode is first attenuated and then enhanced by the collisional effects as the density ratio of the background plasma to the beam increases. Meanwhile, the maximum CFI growth rate is shifted to the long-wavelength region due to both the bulk plasma density increase and the collisional effects, resulting in larger filaments formation. On the other hand, collisional effects mainly attenuate the TSI and finally stabilize it. Numerical solutions under parameters close to the fast ignition scenario (FIS) are given, which show that the CFI growth rate can be enhanced by 2 orders of magnitude instead of being suppressed in the dense region. Therefore, the CFI-induced electron filaments formation and the resultant kinetic anomalous heating are potentially significant for the target heating in the FIS.

Laser channeling in millimeter-scale underdense plasmas of fast-ignition targets

Two dimensional particle-in-cell simulations show that laser channeling in millimeter-scale underdense plasmas is a highly nonlinear and dynamic process involving longitudinal plasma buildup, laser hosing, channel bifurcation and self-correction, and electron heating to relativistic temperatures. The channeling speed is much less than the linear group velocity of the laser. The simulations find that low-intensity channeling pulses are preferred to minimize the required laser energy but with an estimated lower bound on the intensity of I approximately 5x10(18) W/cm(2) if the channel is to be established within 100 ps. The channel is also shown to significantly increase the transmission of an ignition pulse.

Limb remote-preconditioning protects against focal ischemia in rats and contradicts the dogma of therapeutic time windows for preconditioning

Remote ischemic preconditioning is an emerging concept for stroke treatment, but its protection against focal stroke has not been established. We tested whether remote preconditioning, performed in the ipsilateral hind limb, protects against focal stroke and explored its protective parameters. Stroke was generated by a permanent occlusion of the left distal middle cerebral artery (MCA) combined with a 30 min occlusion of the bilateral common carotid arteries (CCA) in male rats. Limb preconditioning was generated by 5 or 15 min occlusion followed with the same period of reperfusion of the left hind femoral artery, and repeated for two or three cycles. Infarct was measured 2 days later. The results showed that rapid preconditioning with three cycles of 15 min performed immediately before stroke reduced infarct size from 47.7+/-7.6% of control ischemia to 9.8+/-8.6%; at two cycles of 15 min, infarct was reduced to 24.7+/-7.3%; at two cycles of 5 min, infarct was not reduced. Delayed preconditioning with three cycles of 15 min conducted 2 days before stroke also reduced infarct to 23.0+/-10.9%, but with two cycles of 15 min it offered no protection. The protective effects at these two therapeutic time windows of remote preconditioning are consistent with those of conventional preconditioning, in which the preconditioning ischemia is induced in the brain itself. Unexpectedly, intermediate preconditioning with three cycles of 15 min performed 12 h before stroke also reduced infarct to 24.7+/-4.7%, which contradicts the current dogma for therapeutic time windows for the conventional preconditioning that has no protection at this time point. In conclusion, remote preconditioning performed in one limb protected against ischemic damage after focal cerebral ischemia.

Limb remote-preconditioning protects against focal ischemia in rats and contradicts the dogma of therapeutic time windows for preconditioning

Remote ischemic preconditioning is an emerging concept for stroke treatment, but its protection against focal stroke has not been established. We tested whether remote preconditioning, performed in the ipsilateral hind limb, protects against focal stroke and explored its protective parameters. Stroke was generated by a permanent occlusion of the left distal middle cerebral artery (MCA) combined with a 30 min occlusion of the bilateral common carotid arteries (CCA) in male rats. Limb preconditioning was generated by 5 or 15 min occlusion followed with the same period of reperfusion of the left hind femoral artery, and repeated for two or three cycles. Infarct was measured 2 days later. The results showed that rapid preconditioning with three cycles of 15 min performed immediately before stroke reduced infarct size from 47.7+/-7.6% of control ischemia to 9.8+/-8.6%; at two cycles of 15 min, infarct was reduced to 24.7+/-7.3%; at two cycles of 5 min, infarct was not reduced. Delayed preconditioning with three cycles of 15 min conducted 2 days before stroke also reduced infarct to 23.0+/-10.9%, but with two cycles of 15 min it offered no protection. The protective effects at these two therapeutic time windows of remote preconditioning are consistent with those of conventional preconditioning, in which the preconditioning ischemia is induced in the brain itself. Unexpectedly, intermediate preconditioning with three cycles of 15 min performed 12 h before stroke also reduced infarct to 24.7+/-4.7%, which contradicts the current dogma for therapeutic time windows for the conventional preconditioning that has no protection at this time point. In conclusion, remote preconditioning performed in one limb protected against ischemic damage after focal cerebral ischemia.

Ozone modifies associations between temperature and cardiovascular mortality: analysis of the NMMAPS data

OBJECTIVES

Both ambient ozone and temperature are associated with human health. However, few data are available on whether ozone modifies temperature effects. This study aims to explore whether ozone modified associations between maximum temperature and cardiovascular mortality in the USA.

METHODS

The authors obtained data from the US National Morbidity, Mortality, and Air Pollution Study (NMMAPS) website. They used two time-series Poisson regression models (a response surface model and a stratification model) to examine whether ozone modified associations between maximum temperature and cardiovascular mortality (CVM) in 95 large US communities during 1987-2000 in summer (June to September). Bayesian meta-analysis was used to pool estimates in each community.

RESULTS

The response surface model was used to examine the joint effects of temperature and ozone on CVM in summer. Results indicate that ozone positively modified the temperature-CVM associations across the different regions. The stratification model quantified the temperature-CVM associations across different levels of ozone. Results show that in general the higher the ozone concentration, the stronger the temperature-CVM associations across the communities. A 10 degrees C increase in temperature on the same day was associated with an increase in CVM by 1.17% and 8.31% for the lowest and highest level of ozone concentrations in all communities, respectively.

CONCLUSION

Ozone modified temperature effects in different regions in the USA. It is important to evaluate the modifying role of ozone when estimating temperature-related health impacts and to further investigate the reasons behind the regional variability and mechanism for the interaction between temperature and ozone.

In vitro interactions between apricitabine and other deoxycytidine analogues

Apricitabine is a novel deoxycytidine analogue reverse transcriptase inhibitor that is under development for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. Apricitabine is phosphorylated to its active triphosphate by deoxycytidine kinase, which is also responsible for the intracellular phosphorylation of lamivudine (3TC) and emtricitabine (FTC); hence, in vitro studies were performed to investigate possible interactions between apricitabine and these agents. Human peripheral blood mononuclear cells (PBMC) were incubated for 24 h with various concentrations of (3)H-labeled or unlabeled apricitabine, 3TC, or FTC. Intracellular concentrations of parent compounds and their phosphorylated derivatives were measured by high-performance liquid chromatography. In other experiments, viral reverse transcriptase activity was measured in PBMC infected with HIV-1 bearing M184V in the presence of various concentrations of apricitabine and 3TC. [(3)H]apricitabine and [(3)H]3TC were metabolized intracellularly to form mono-, di-, and triphosphates. 3TC and FTC (1 to 10 microM) produced concentration-dependent decreases in apricitabine phosphorylation; in contrast, apricitabine at concentrations of up to 30 muM had no effect on the phosphorylation of 3TC or FTC. The combination of apricitabine and 3TC reduced the antiviral activity of apricitabine against HIV-1: apricitabine concentrations producing 50% inhibition of viral reverse transcriptase were increased two- to fivefold in the presence of 3TC. These findings suggest that nucleoside reverse transcriptase inhibitors with similar modes of action may show biochemical interactions that affect their antiviral efficacy. It is therefore essential that potential interactions between combinations of new and existing agents be thoroughly investigated before such combinations are introduced into clinical practice.

Fatty acid profiling of soybean cotyledons by near-infrared spectroscopy

Genetically improved soybean grain often contains altered fatty acid profiles. Such alterations can have deleterious effects on seed germination and seedling development, making it necessary to monitor fatty acid profiles in follow-up physiological studies. The objective of this research was to quantify the five fatty acids in soybean (Glycine max) cotyledons using near-infrared (NIR) spectroscopy. Soybean cotyledon samples were dried, ground, and scanned with visible and NIR radiation from 400 to 2500 nm, and reflectance was recorded. Samples were also analyzed by gas chromatography (GC) for palmitic, stearic, oleic, linoleic, and linolenic acids and total oil; GC data, expressed as actual concentration and proportion of total oil, were regressed against spectral data to develop calibration equations. Equation statistics indicated that four of the five fatty acids could be predicted accurately by NIR spectroscopy; the fifth fatty acid could be determined by subtraction. Principal component analysis revealed that most of the spectral variation in this population was due to chlorophyll absorbance in the visible region. Therefore, the spectra were trimmed to include the NIR region only (1100-2500 nm), and a second set of equations was developed. Equations based exclusively on NIR spectra had equal or greater precision than equations based on visible and NIR spectra. Principal component analysis and partial least squares analysis revealed that even after trimming, at least 90% of the spectral variation was unrelated to fatty acid, though variation from fatty acid was identified in the second and third principal components. This research provides an NIR method for complete fatty acid profiling of soybean cotyledons. Equations were achieved with NIR spectra only, so spectrophotometers that analyze both the visible and NIR regions are not needed for this analysis. In addition, equations were possible with a 250 mg sample, which is one-tenth the normal sample size for this analysis.

Cooperative effects of adenoviral vector-mediated interleukin 12 gene therapy with radiotherapy in a preclinical model of metastatic prostate cancer

We investigated the potential benefits of combining adenoviral vector mediated in situ interleukin-12 (AdmIL-12) gene therapy with radiation therapy (XRT) to enhance therapeutic efficacy. In a metastatic mouse prostate cancer cell line, 178-2 BMA, AdmIL-12+XRT demonstrated enhanced therapeutic activities in vitro as determined by clonogenic survival, apoptosis, and mIL-12 levels. At the molecular level, increased expression of tumor necrosis factor-alpha mRNA was specific for the combined therapy. In a subcutaneous 178-2 BMA in vivo model, the combination of AdmIL-12+XRT produced statistically significant tumor growth suppression compared to control vector Adbetagal, Adbetagal XRT, or AdmIL-12 as monotherapy. In addition, significant prolongation of survival was demonstrated for the combination of AdmIL-12+XRT. The combination of AdmIL-12+XRT significantly suppressed both spontaneous and pre-established lung metastases, and led to a prolonged elevation of serum IL-12 and significantly increased natural killer (NK) activities. Importantly, in vivo depletion of NK cells resulted in significant attenuation of the antimetastatic activities of AdmIL-12 alone or AdmIL-12+XRT. These combined effects suggest that AdIL-12 gene therapy together with radiotherapy may achieve maximal tumor control (both local and systemic) in selected prostate cancer patients via radio-gene therapy induced local cytotoxicity and local and systemic antitumor immunity.

Intraperitoneal gene therapy by rAAV provides long-term survival against epithelial ovarian cancer independently of survivin pathway

Epithelial ovarian carcinoma is the leading cause of death from gynecological malignancies. Owing to the lack of an effective screening method, insidious onset, and non-specific symptoms, a majority of women present with advanced stage disease. Despite improvements from cytoreductive surgery and chemotherapy, recurrent disease remains a formidable challenge. In the present study, we demonstrate for the first time that stable intra-abdominal genetic transfer of endostatin and angiostatin (E+A) by recombinant adeno-associated virus (rAAV) provides sustained antitumor effects on the growth and dissemination of epithelial ovarian cancer in a mouse model. Further, when combined with paclitaxel (taxol), the effect of this therapy was dramatically increased and resulted in long-term tumor-free survival overcoming prior limitations of chemotherapy and gene therapy. The combined effects of angiosuppressive therapy and chemotherapy were found to be independently of survivin pathway. Evidence for the superior effects of the combination therapy was indicated by significantly lower ascites volume with less hemorrhage and tumor conglomerates, lower ascites vascular endothelial growth factor, higher tumor cell apoptosis and decreased blood vasculature, and long-term disease-free survival. Histopathology of visceral organs and liver enzyme assays indicated no toxicity or pathology.

In vitro antiretroviral activity and in vitro toxicity profile of SPD754, a new deoxycytidine nucleoside reverse transcriptase inhibitor for treatment of human immunodeficiency virus infection

SPD754 (AVX754) is a deoxycytidine analogue nucleotide reverse transcriptase inhibitor (NRTI) in clinical development. These studies characterized the in vitro activity of SPD754 against NRTI-resistant human immunodeficiency virus type 1 (HIV-1) and non-clade B HIV-1 isolates, its activity in combination with other antiretrovirals, and its potential myelotoxicity and mitochondrial toxicity. SPD754 was tested against 50 clinical HIV-1 isolates (5 wild-type isolates and 45 NRTI-resistant isolates) in MT-4 cells using the Antivirogram assay. SPD754 susceptibility was reduced 1.2- to 2.2-fold against isolates resistant to zidovudine (M41L, T215Y/F, plus a median of three additional nucleoside analogue mutations [NAMs]) and/or lamivudine (M184V) and was reduced 1.3- to 2.8-fold against isolates resistant to abacavir (L74V, Y115F, and M184V plus one other NAM) or stavudine (V75T/M, M41L, T215F/Y, and four other NAMs). Insertions at amino acid position 69 and Q151M mutations (with or without M184V) reduced SPD754 susceptibility 5.2-fold and 14- to 16-fold, respectively (these changes gave values comparable to or less than the corresponding values for zidovudine, lamivudine, abacavir, and didanosine). SPD754 showed similar activity against isolates of group M HIV-1 clades, including A/G, B, C, D, A(E), D/F, F, and H. SPD754 showed additive effects in combination with other NRTIs, tenofovir, nevirapine, or saquinavir. SPD754 had no significant effects on cell viability or mitochondrial DNA in HepG2 or MT-4 cells during 28-day exposure at concentrations up to 200 microM. SPD754 showed a low potential for myelotoxicity against human bone marrow. In vitro, SPD754 retained activity against most NRTI-resistant HIV-1 clinical isolates and showed a low propensity to cause myelotoxicity and mitochondrial toxicity.