Fingerprints of hydrogen bonding in the terahertz dynamics of ethanol and water: An inelastic x-ray scattering study

We used inelastic x-ray scattering methods to measure the terahertz spectrum of density fluctuations of ethanol in both liquid and solid phases. The results of a Bayesian inference-based lineshape analysis with a multiple excitation model and the comparison with a previous similar analysis on water indicate that the different structures induced by hydrogen bonds in ethanol and water have a profound influence on the respective dynamic responses, the latter being characterized by longer living and better resolved high-frequency acoustic excitations. In addition, we compare these findings with those obtained with an alternative approach based on the exponential expansion theory and ensuring sum rules fulfillment, demonstrating that the model's choice directly impacts the number of spectral modes detected.

Deadly and venomous Lonomia caterpillars are more than the two usual suspects

Caterpillars of the Neotropical genus Lonomia (Lepidoptera: Saturniidae) are responsible for some fatal envenomation of humans in South America inducing hemostatic disturbances in patients upon skin contact with the caterpillars' spines. Currently, only two species have been reported to cause hemorrhagic syndromes in humans: Lonomia achelous and Lonomia obliqua. However, species identifications have remained largely unchallenged despite improved knowledge of venom diversity and growing evidence that the taxonomy used over past decades misrepresents and underestimates species diversity. Here, we revisit the taxonomic diversity and distribution of Lonomia species using the most extensive dataset assembled to date, combining DNA barcodes, morphological comparisons, and geographical information. Considering new evidence for seven undescribed species as well as three newly proposed nomenclatural changes, our integrative approach leads to the recognition of 60 species, of which seven are known or strongly suspected to cause severe envenomation in humans. From a newly compiled synthesis of epidemiological data, we also examine the consequences of our results for understanding Lonomia envenomation risks and call for further investigations of other species' venom activities. This is required and necessary to improve alertness in areas at risk, and to define adequate treatment strategies for envenomed patients, including performing species identification and assessing the efficacy of anti-Lonomia serums against a broader diversity of species.

First evidence of ranavirus in native and invasive amphibians in Colombia

Ranaviruses can cause mass mortality events in amphibians, thereby becoming a threat to populations that are already facing dramatic declines. Ranaviruses affect all life stages and persist in multiple amphibian hosts. The detrimental effects of ranavirus infections to amphibian populations have already been observed in the UK and in North America. In Central and South America, the virus has been reported in several countries, but the presence of the genus Ranavirus (Rv) in Colombia is unknown. To help fill this knowledge gap, we surveyed for Rv in 60 species of frogs (including one invasive species) in Colombia. We also tested for co-infection with Batrachochytrium dendrobatidis (Bd) in a subset of individuals. For Rv, we sampled 274 vouchered liver tissue samples collected between 2014 and 2019 from 41 localities covering lowlands to mountaintop páramo habitat across the country. Using quantitative polymerase chain reaction (qPCR) and end-point PCR, we detected Rv in 14 individuals from 8 localities, representing 6 species, including 5 native frogs of the genera Osornophryne, Pristimantis and Leptodactylus, and the invasive American bullfrog Rana catesbeiana. Bd was detected in 7 of 140 individuals, with 1 co-infection of Rv and Bd in an R. catesbeiana specimen collected in 2018. This constitutes the first report of ranavirus in Colombia and should set off alarms about this new emerging threat to amphibian populations in the country. Our findings provide some preliminary clues about how and when Rv may have spread and contribute to understanding how the pathogen is distributed globally.

Response to: A paleoecological context to assess the development of oak forest in Colombia: A comment on Zorrilla-Azcué, S., González-Rodríguez, A., Oyama, K., González, M.A. & Rodríguez-Correa, H., The DNA history of a lonely oak: Quercus humboldtii phylogeography in the Colombian Andes. Ecology and Evolution 2021, doi:10.1002/ece3.7529

In this response, we address comments and clarify the rationale behind the choice of hypotheses aimed to describe the Quercus humboldtii phylogeography in the Colombian Andes. Finally, we explain our disagreement with the conclusions of a previous critique, since these are not necessarily adequate under the implemented population genetics approach.

Development of Novel Management Tools for Phortica variegata (Diptera: Drosophilidae), Vector of the Oriental Eyeworm, Thelazia callipaeda (Spirurida: Thelaziidae), in Europe

Lachryphagous males of Phortica variegata (Fallén, 1823) are gaining increasing attention in Europe, as they act as vectors of the nematode Thelazia callipaeda Railliet & Henry, 1910, causal agent of thelaziosis, an emergent zoonotic disease. Currently, there are no effective control strategies against the vector, and surveillance and monitoring rely on time-consuming and nonselective sampling methods. Our aim was to improve the knowledge about the population dynamics and the chemical ecology of the species. A total of 5,726 P. variegata flies (96.4% males and 3.6% females, mostly gravid) were collected in field experiments during June-September of 2020 in an oak forest in northern Spain. Our results indicate that 1) by means of sweep netting a significantly higher number of captures were found both around the collector´s body and in the air than at ground level; 2) a positive relationship was detected between the abundance of Phortica flies and temperature, with two significant peaks of abundance at 24 and 33°C; 3) the blend of red wine and cider vinegar was the most attractive bait; 4) yellow traps captured fewer flies compared to black and transparent traps; and 5) a significant reduction toward vinegar and wine was detected in presence of the phenolic monoterpenoid carvacrol. In addition, all the males (n = 690) analyzed by both molecular detection and dissection resulted negative for the presence of T. callipaeda larvae. Overall, these findings provide a better understanding of the vector in terms of monitoring and management strategies.

Simplified risk-prediction for benchmarking and quality improvement in emergency general surgery. Prospective, multicenter, observational cohort study

BACKGROUND AND AIMS

Emergency General Surgery (EGS) conditions account for millions of deaths worldwide, yet it is practiced without benchmarking-based quality improvement programs. The aim of this observational, prospective, multicenter, nationwide study was to determine the best benchmark cutoff points in EGS, as a reference to guide improvement measures.

METHODS

Over a 6-month period, 38 centers (5% of all public hospitals) attending EGS patients on a 24-h, 7-days a week basis, enrolled consecutive patients requiring an emergent/urgent surgical procedure. Patients were stratified into cohorts of low (i.e., expected morbidity risk <33%), middle and high risk using the novel m-LUCENTUM calculator.

RESULTS

A total of 7258 patients were included; age (mean ± SD) was 51.1 ± 21.5 years, 43.2% were female. Benchmark cutoffs in the low-risk cohort (5639 patients, 77.7% of total) were: use of laparoscopy ≥40.9%, length of hospital stays ≤3 days, any complication within 30 days ≤ 17.7%, and 30-day mortality ≤1.1%. The variables with the greatest impact were septicemia on length of hospital stay (21 days; adjusted beta coefficient 16.8; 95% CI: 15.3 to 18.3; P < .001), and respiratory failure on mortality (risk-adjusted population attributable fraction 44.6%, 95% CI 29.6 to 59.6, P < .001). Use of laparoscopy (odds ratio 0.764, 95% CI 0.678 to 0.861; P < .001), and intraoperative blood loss (101-500 mL: odds ratio 2.699, 95% CI 2.152 to 3.380; P < .001; and 500-1000 mL: odds ratio 2.875, 95% CI 1.403 to 5.858; P = .013) were associated with increased morbidity.

CONCLUSIONS

This study offers, for the first time, clinically-based benchmark values in EGS and identifies measures for improvement.

First Findings and Molecular Data of Phlebotomus mascittii (Diptera: Psychodidae) in the Cantabrian Cornice (Northern Spain)

Phlebotomus (Transphlebotomus) mascittii Grassi, 1908 (Diptera: Psychodidae) has been found in several European countries. In Spain, sporadic records were reported in the early '80s in Catalonia (Northeast Spain), and it was never detected again. Recent entomological surveys carried out between 2004 and 2020 revealed the presence of several specimens of P. mascittii in Spain. The species identification was confirmed by both morphological and molecular analyses. The analyzed specimens belonged to the haplotype (COI_2) defined by one polymorphic site compared to other European specimens. Phlebotomus mascittii was found in low population densities in rural areas associated with livestock farms and in an urban cemetery during the summer season. This study provides the first records of this species in various localities along the Cantabrian cornice (Northern Spain) and represents its westernmost observation in the Palearctic region. The implications of the finding of this uncommon species are discussed at different levels, with emphasis on its suspected role in the transmission of leishmaniosis.

The DNA history of a lonely oak: Quercus humboldtii phylogeography in the Colombian Andes

The climatic and geological changes that occurred during the Quaternary, particularly the fluctuations during the glacial and interglacial periods of the Pleistocene, shaped the population demography and geographic distribution of many species. These processes have been studied in several groups of organisms in the Northern Hemisphere, but their influence on the evolution of Neotropical montane species and ecosystems remains unclear. This study contributes to the understanding of the effect of climatic fluctuations during the late Pleistocene on the evolution of Andean mountain forests. First, we describe the nuclear and plastidic DNA patterns of genetic diversity, structure, historical demography, and landscape connectivity of Quercus humboldtii, which is a typical species in northern Andean montane forests. Then, these patterns were compared with the palynological and evolutionary hypotheses postulated for montane forests of the Colombian Andes under climatic fluctuation scenarios during the Quaternary. Our results indicated that populations of Q. humboldtii have high genetic diversity and a lack of genetic structure and that they have experienced a historical increase in connectivity from the last glacial maximum (LGM) to the present. Furthermore, our results showed a dramatic reduction in the effective population size followed by an expansion before the LGM, which is consistent with the results found by palynological studies, suggesting a change in dominance in Andean forests that may be related to ecological factors rather than climate change.

Culicoides biting midges and mosquito fauna at three dog and cat shelters in rural and periurban areas in Northern Spain

The diversity and abundance of Culicoides (Diptera: Ceratopogonidae) and mosquitoes (Diptera: Culicidae) were studied in three animal protection centres (APCs) in Northern Spain between 1 July and 31 October 2018. Four miniature suction CDC light traps (two UV and two standard incandescent bulb traps, both types baited and non-baited with CO₂ ) were placed in each APC to compare their efficiency in the collection of these Diptera groups. A total of 1176 biting midges (14 species), 224 mosquitoes (8 species) and 1 black fly were collected and identified by both morphological and molecular approaches. The Culicoides obsoletus complex (C. obsoletus/C. scoticus) accounted for 58.2% of the total collection within the Ceratopogonidae family, whereas Culex pipiens/Cx. torrentium comprised 76.8% of the Culicidae. The input of CO₂ in light traps proved largely ineffective in improving the collections of both Diptera groups. UV-light traps were 7.8 and 2.2 times more effective than incandescent light traps in trapping Culicoides and mosquitoes, respectively. Seasonal dynamics differed between both Diptera taxa but captures of both taxa were significantly larger at the beginning of the summer. The epidemiological relevance of the most prevalent species is also discussed.

Determinants of the current and future distribution of the West Nile virus mosquito vector Culex pipiens in Spain

Changes in environmental conditions, whether related or not to human activities, are continuously modifying the geographic distribution of vectors, which in turn affects the dynamics and distribution of vector-borne infectious diseases. Determining the main ecological drivers of vector distribution and how predicted changes in these drivers may alter their future distributions is therefore of major importance. However, the drivers of vector populations are largely specific to each vector species and region. Here, we identify the most important human-activity-related and bioclimatic predictors affecting the current distribution and habitat suitability of the mosquito Culex pipiens and potential future changes in its distribution in Spain. We determined the niche of occurrence (NOO) of the species, which considers only those areas lying within the range of suitable environmental conditions using presence data. Although almost ubiquitous, the distribution of Cx. pipiens is mostly explained by elevation and the degree of urbanization but also, to a lesser extent, by mean temperatures during the wettest season and temperature seasonality. The combination of these predictors highlights the existence of a heterogeneous pattern of habitat suitability, with most suitable areas located in the southern and northeastern coastal areas of Spain, and unsuitable areas located at higher altitude and in colder regions. Future climatic predictions indicate a net decrease in distribution of up to 29.55%, probably due to warming and greater temperature oscillations. Despite these predicted changes in vector distribution, their effects on the incidence of infectious diseases are, however, difficult to forecast since different processes such as local adaptation to temperature, vector-pathogen interactions, and human-derived changes in landscape may play important roles in shaping the future dynamics of pathogen transmission.

Advanced-stage mycosis fungoides: role of the signal transducer and activator of transcription 3, nuclear factor-κB and nuclear factor of activated T cells pathways

BACKGROUND

The malignant mechanisms that control the development of cutaneous T-cell lymphoma (CTCL) are beginning to be identified. Recent evidence suggests that disturbances in specific intracellular signalling pathways, such as RAS-mitogen-activated protein kinase, T-cell receptor (TCR)-phospholipase C gamma 1 (PLCG1)-nuclear factor of activated T cells (NFAT) and Janus kinase (JAK)-signal transducer and activator of transcription (STAT), may play an essential role in the pathogenesis of CTCL.

OBJECTIVES

To investigate the mechanisms controlling disease development and progression in mycosis fungoides (MF), the most common form of CTCL.

METHODS

We collected 100 samples that were submitted for diagnosis of, or a second opinion regarding, MF between 2001 and 2018, 80% of which were in the early clinical stages of the disease. Formalin-fixed paraffin-embedded tissues were used for histological review and to measure the expression by immunohistochemistry of surrogate markers of activation of the TCR-PLCG1-NFAT, JAK-STAT and NF-κB pathways. Folliculotropism and large-cell transformation were also examined.

RESULTS

NFAT and nuclear factor kappa B (NF-κB) markers showed a comparable activation status in early and advanced stages, while STAT3 activation was more frequent in advanced stages and was associated with large-cell transformation. Consistently with this observation, STAT3 activation occurred in parallel with MF progression in two initially MF-negative cases. A significant association of NFAT with NF-κB markers was also found, reflecting a common mechanism of activation in the two pathways. Genomic studies identified nine mutations in seven genes known to play a potential role in tumorigenesis in T-cell leukaemia/lymphoma, including PLCG1, JAK3 and STAT3, which underlies the activation of these key cell-survival pathways. A higher mutational allele frequency was detected in advanced stages.

CONCLUSIONS

Our results show that STAT3 is activated in advanced cases and is associated with large-cell transformation, while the activation of NFAT and NF-κB is maintained throughout the disease. These findings could have important diagnostic and therapeutic implications. What's already known about this topic? Mycosis fungoides is characterized by a clonal expansion of T cells in the skin. The mechanisms controlling disease development and progression are not fully understood. What does this study add? An association of the nuclear factor of activated T cells and nuclear factor kappa B pathways was found, which could reflect a common mechanism of activation. These pathways were activated in early and advanced stages at the same level. Signal transducer and activator of transcription 3 activation was associated with large-cell transformation and was more frequent in advanced stages. A genomic analysis of cutaneous T-cell lymphoma-associated genes was performed. Nine mutations were detected. What is the translational message? These results could have important implications for the treatment of MF in the near future.

Dynamic electrophoretic mobility and electric permittivity of concentrated suspensions of plate-like gibbsite particles

In this paper we present experimental results on the electrokinetic behavior of planar gibbsite particles in concentrated suspensions. The dc electrophoretic mobility measurements are in this case of little significance, as they are scarcely informative. In the present investigation, we show that the dielectric dispersion and dynamic electrophoresis can in contrast provide such information. The complicating factors are of course the non-spherical shape and the finite particle concentration, as no complete theory of these phenomena exists for such systems. We propose to use first of all a model of dynamic electrophoresis of spheroids in which the effect of volume fraction is considered by means of an approximate theory previously obtained for spheres, based on the evaluation of electrical and hydrodynamic interactions between particles. In addition, the role of volume fraction on the high frequency inertial relaxation is also ascertained and used to obtain a volume fraction-independent radius of the gibbsite spheroids. A similar approach is used for the evaluation of dielectric dispersion data. Both the dynamic mobility and dielectric constant dependencies on frequency were obtained for gibbsite suspensions of different volume fractions in 0.5mMKCl. The theoretical treatments elaborated were applied to these data, and a coherent picture of the geometrical and electrical characteristics of the particles was obtained.

Frequency-fluctuation model applied to Stark-Zeeman spectral line shapes in plasmas

A very fast method for calculating line shapes in the presence of an external magnetic field accounting for charge particle dynamics is proposed. It is based on a reformulation of the frequency fluctuation model, which provides an expression of the dynamic line shape as a functional of the static distribution function of frequencies. In the presence of an external magnetic field, the distribution of intensity and polarization of the emission depends on the angle between the observation line and the magnetic field's direction. Comparisons with numerical simulations and experimental results for various plasma conditions show very good agreement. Results on hydrogen lines in the context of magnetic fusion and the Lyman-α line, accounting for fine structure, emitted by argon in the context of inertial fusion, are also presented.

Monitoring bluetongue disease (BTV-1) epidemic in southern Spain during 2007

On the 25th of July 2007, bluetongue virus (BTV) serotype 1 was detected in Andalusia, southern Spain for the first time. A total of 4436 farms infected with BTV-1 were confirmed during that year: 3162 in sheep flocks, 113 in goat flocks, 7 in cattle herds and 1154 in mixed farms (sheep, goat and/or cattle in the same farm). The most common clinical signs were: fever, depression, lethargy, facial edema, and salivation (observed in more than 70% of the infected farms). Lesions in oral mucosa, lameness and dyspnea were also frequently observed. Median morbidity rate in sheep and goat flocks were 6.3% and 2.7% respectively. Median mortality rate was 2.2% in sheep flocks and 1.2% in goat flocks. Median case fatality rate was 29.8% in sheep flocks and 45% in goat flocks. Morbidity and mortality rates were not significantly higher in sheep flocks than in goat flocks (p>0.05), whereas case fatality rate was significant higher in goat flocks compared to sheep flocks (p<0.05). Neither clinical signs nor mortality were observed in cattle herds. The spatial distribution of the risk of BTV infection over Andalusia by municipality was evaluated by means of a hierarchical Bayesian model. The results evidenced that the risk was not homogeneous over the territory, being higher in the western part of the region. The likelihood of BTV infection was increased between 1.01 and 1.16 times by an increase of 10,000 domestic ruminants, and between 1.01 and 1.69 times by the presence of red deer (Cervus elaphus) in the municipality.

Human adult stem cells derived from adipose tissue protect against experimental colitis and sepsis

BACKGROUND AND AIMS

Inflammatory bowel diseases (IBDs) are associated with uncontrolled innate and adaptive immunity against normal constituents, including commensal bacteria and microbial products. Mesenchymal stem cells (MSCs) suppress effector T cell responses and have beneficial effects in various immune disorders. This work investigates the therapeutic effects of human adipose-derived MSCs (hASCs) in various models of IBD and sepsis.

METHODS

Acute and chronic colitis was induced in mice with dextran sulfate sodium. Sepsis was induced by caecal ligation and puncture or by endotoxin injection. Colitic and septic mice were treated intraperitoneally with hASCs or murine ASCs, and diverse disease clinical signs and mortality were determined. The levels of various inflammatory cytokines and chemokines, T helper 1(Th1)-type response and generation of regulatory T cells (Treg) were determined in affected organs.

RESULTS

Systemic infusion of ASCs significantly ameliorated the clinical and histopathological severity of colitis, abrogating weight loss, diarrhoea and inflammation, and increasing survival. The therapeutic effect was associated with downregulation of the Th1-driven inflammatory responses. ASCs decreased a wide panel of inflammatory cytokines and chemokines and increased interleukin 10 (IL10), acting on macrophages. hASCs also impaired Th1 cell activation in both colonic mucosa and draining lymph nodes. The induction of IL10-secreting Treg was partially involved in the therapeutic effect of hASCs. Moreover, ASCs protected from severe sepsis by reducing the infiltration of inflammatory cells in various target organs and by downregulating the production of various inflammatory mediators.

CONCLUSIONS

hASCs emerge as key regulators of immune/inflammatory responses in vivo and as attractive candidates for cell-based treatments for IBD and sepsis.

Magnetic proximity effect features in antiferromagnetic/ferrimagnetic core-shell nanoparticles

A study of "inverted" core-shell, MnO/gamma-Mn(2)O(3), nanoparticles is presented. Crystal and magnetic structures and characteristic sizes have been determined by neutron diffraction for the antiferromagnetic core (MnO) and the ferrimagnetic shell (gamma-Mn(2)O(3)). Remarkably, while the MnO core is found to have a T_{N} not far from its bulk value, the magnetic order of the gamma-Mn(2)O(3) shell is stable far above T_{C}, exhibiting two characteristic temperatures, at T approximately 40 K [T_{C}(gamma-Mn(2)O(3))] and at T approximately 120 K [ approximately T_{N}(MnO)]. Magnetization measurements are consistent with these results. The stabilization of the shell moment up to T_{N} of the core can be tentatively attributed to core-shell exchange interactions, hinting at a possible magnetic proximity effect.

Measurements of Hbeta Stark central asymmetry and its analysis through standard theory and computer simulations

Experimental measurements of the center of the H_{beta} Stark profile on three different installations have been done to study its asymmetry in wide ranges of electron density, temperature, and plasma conditions. Theoretical calculations for the analysis of experimental results have been performed using the standard theory and computer simulations and included separately quadrupolar and quadratic Stark effects. Earlier experimental results and theoretical calculations of other authors have been reviewed as well. The experimental results are well reproduced by the calculations at high and moderate densities.

[Anesthetic management of sacroiliac-vertebral echinococcosis]

Bone echinococcosis affects the spine and pelvis in 60% of cases. Bone lesions may be silent for between 10 and 20 years. The capsules progress aggressively through the medullary canal and replace the trabecular bone without forming cysts, as occurs in the organs, thus making anaplylaxis rare. The combination of chemotherapy and surgery facilitates anesthetic management and reduces the incidence of anaphylactic events and disease recurrence.

Influence of KIR gene diversity on the course of HSV-1 infection: resistance to the disease is associated with the absence of KIR2DL2 and KIR2DS2

Herpes simplex virus type 1 (HSV-1) causes lifelong latent infections in most humans. Periodical virus reactivations from latency in the neurons of sensitive ganglia lead to transport to mucocutaneous regions and productive replication, which results in recurrent inflammatory herpetic lesions or in asymptomatic virus shedding. The medical consequences of such lesions and the frequency of recurrences vary greatly in different subjects. Furthermore, many infected individuals never suffer manifestations of the disease, even when exposed to stimuli that trigger clinical recurrences in other humans. The origin of the variability in the clinical course of HSV-1 infection remains unexplained. Herpesviruses and other pathogens sabotage the expression of major histocompatibility complex class I molecules by infected cells, thus subverting T-cell-mediated immunity. Subversion of antigen presentation is counteracted by natural killer cells, which survey the human leukocyte antigen (HLA) expression by specific receptors. These include the killer cell immunoglobulin-like receptors (KIRs), which are encoded by a complex of extremely diverse and rapidly evolving genes. Here, we analyze the contribution of KIR gene diversity to the variable clinical course of HSV-1 infection by comparing the distribution of these genes in humans with clinical manifestations of the disease with that in asymptomatically infected donors. This study provides preliminary evidence that the receptors KIR2DL2 and KIR2DS2 predispose to symptomatic HSV-1 infection and favor the frequently recurring forms of the disease. Possible contribution of the 'HLA-C1' ligand to HSV-1 disease was not statistically supported. Because of an absolute genetic linkage between KIR2DL2 and KIR2DS2, we could not determine which receptor was primarily responsible for the observed association, but our results suggest that presence in the genome of KIR2DL2 and KIR2DS2 hinders an effective cellular response to HSV-1.

Plasma and urine pharmacokinetics of niacin and its metabolites from an extended-release niacin formulation

OBJECTIVE

To characterize plasma and urine pharmacokinetics of niacin and its metabolites after oral administration of 2,000 mg of extended-release (ER) niacin in healthy male volunteers.

METHODS

Niacin ER was administered to 12 healthy male subjects following a low-fat snack. Plasma was collected for 12 h post dose and was analyzed for niacin, nicotinuric acid (NUA), nicotinamide (NAM) and nicotinamide-N-oxide (NNO). Urine was collected for 96 h post dose and analyzed for niacin and its metabolites, NUA, NAM, NNO, N-methylnicotinamide (MNA) and N-methyl-2-pyridone-5-carboxamide (2PY).

RESULTS

Mean niacin Cmax and AUC(0-t) values were 9.3 microg/ml and 26.2 microg x h/ml and were the highest of all analytes measured. Peak niacin and NUA levels occurred at 4.6 h (median) while tmax for NAM and NNO were 8.6 and 11.1 h, respectively. The mean plasma terminal half-life for niacin (0.9 h) and NUA (1.3 h) was shorter as compared to NAM (4.3 h). Urine recovery of niacin and metabolites accounted for 69.5% of the administered dose; only 3.2% was excreted as niacin. The highest recovery was for 2PY (37.9%), followed by MNA (16.0%) and NUA (11.6%). Mean half-lives for 2PY and MNA calculated in urine were 12.6 and 12.8 h, respectively.

CONCLUSIONS

Niacin was extensively metabolized following oral administration, and about 70% of the administered dose is recovered in urine in 96 h as niacin, NUA, MNA, NNO, NAM and 2PY. The plasma levels of the parent niacin were higher than its metabolites though only about 3% of the unchanged drug is recovered in urine.

[Intra-abdominal desmoid tumor]

Aggressive fibromatosis (desmoid tumor) are rare connective tissue tumors that occur sporadically or in association with familial adenomatous polyposis. The etiology is unknown and clinical findings depend on growth into neighboring structures. Biopsy is required to establish the diagnosis. The treatment of choice is surgery. We report a case with unusual localization in this form of presentation. The patient remains asymptomatic 15 months after surgery.

A measles outbreak in children under 15 months of age in La Rioja, Spain, 2005-2006

This paper describes a measles outbreak in La Rioja, Spain, which began in December 2005 and mainly affected children under 15 months of age who were not yet immunised with MMR vaccine. The measles cases were detected by the mandatory reporting system, under which laboratories must report every confirmed measles case. Cases were classified in accordance with the National Measles Elimination Plan: suspected and laboratory-confirmed. In the period 14 December 2005 to 19 February 2006, 29 suspected cases of measles were investigated, and 18 were confirmed. The mean incubation period was 13.8 days (range: 9 to 18). Of the 18 confirmed cases, only two were in adults. MMR vaccination was recommended for all household contacts, as well as for children aged 6 to 14 months who attended the daycare centres where the cases had appeared. At these centres, the second dose of MMR was administered ahead of schedule for children under three years of age. It was recommended that the first dose of MMR vaccine be administered ahead of schedule for all children aged 9 to 14 months. During an outbreak of measles, children aged 6 months or older, who have not previously been vaccinated against measles, mumps and rubella, should receive a first dose as soon as possible, and those who have had a first dose should receive a second dose as soon as possible, provided that a minimum of one month has elapsed between the two doses.

Unconventional density dependence of the stochastic dynamics in an organic liquid

The density dependence of the diffusive rotational and center-of-mass dynamics of 2-methyl-pyridine is investigated by means of the concurrent use of quasielastic neutron scattering and molecular dynamics simulations. The dependence of both translation and rotational diffusion coefficients shows a distinctive change of slope with increasing density taking place about rho=0.975 g/cm3. Such a change in the dynamics can be related to observations made in other liquids composed of oblate-spheroidal particles.

Dose-proportional pharmacokinetics of a methylphenidate extended-release capsule

OBJECTIVE

To assess the dose-proportionality of the 10 mg, 20 mg and 30 mg methylphenidate extended-release (MPH ER) capsule formulations in healthy adults.

MATERIALS

Metadate CD (methylphenidate HCl, USP) extended-release capsules (10, 20 and 30 mg) were obtained from Celltech Manufacturing Inc. (Rochester, NY, USA).

METHODS

This was a single-center, single-dose, fasted, randomized, open-label, 3-way crossover study with a 1-week washout period between doses, in 24 healthy male and female subjects, aged 21-40 years. MPH plasma concentration-time data were used to calculate the pharmacokinetic parameters for each treatment. The 20 mg capsule, the first FDA-approved dosage strength, was used as reference treatment.

RESULTS

Twenty-three subjects completed all 3 study periods. Regardless of the dose, MPH ER capsules exhibited similar PK profiles as evidenced by a biphasic absorption profile, consisting of a sharp initial increase followed by a second increase in MPH plasma levels, all occurring at the same times. All 90% confidence intervals for the 10:20 mg and 30:20 mg dose-normalized geometric mean ratios were within the 80-125% FDA limits for bioequivalence. This was true for Cmax (maximum observed concentration), AUC(0-last) (area under the plasma concentration curve from time 0 to the last measurable time point) and AUC(0-inf) (area under the plasma concentration curve from time 0 to infinity). Adverse events were mild and the number and types of adverse events experienced by subjects did not differ among the 3 dosages.

CONCLUSION

Data collected from this study demonstrate the dose proportionality of the new 10 mg and 30 mg dosage strengths of MPH ER capsules with the 20 mg capsule. The availability and predictability of these dosage strengths should facilitate dose titration of ADHD patients.

Multiple-trait analysis of fluctuating asymmetry levels in anthropogenically and naturally stressed sites: a case study using Chironomus riparius Meigen, 1804 larvae

Fluctuating asymmetry levels were measured in fourth-instar Chironomus riparius larvae collected from various sampling sites in Galicia (northwest Spain) subjected to different types and degrees of stress. Specifically, we selected sites with contamination of anthropogenic origin, ranging from urban and industrial sewages to organic wastes, as well as two sites without chemical contamination, but with marked diurnal variations in their physicochemical conditions. Fluctuating asymmetry levels were determined for various structures of the head capsule (antennal segment I length, antennal segment II length, mentum width, and number of pecten epipharyngis teeth). The results obtained group the sampling sites in a similar way to other measures of stress. In particular, grouping resulted to be similar to that obtained after analysis of head capsule deformities. Moreover, results of our work are consistent with the hypothesis that some characters may possibly be useful indicators of specific types of stress.

Candida dubliniensis, a new fungal pathogen

There is a high interest in Candida species other than Candida albicans because of the rise and the epidemiological shifts in candidiasis. These emerging Candida species are favored by the increase of immunocompromised patients and the use of new medical practices, and m. Most oropharyngeal candidiasis can be foundare observed in those HIV-infected patients infected with human immunodeficiency virus (HIV). Candida dubliniensis is a recently described opportunistic pathogen that is closely related to C. albicans but differs from it with respect to epidemiology, certain virulence characteristics, and the ability to develop fluconazole resistance in vitro. C. dubliniensis has been linked to oral candidiasis in AIDS patients, although it has recently been associated to invasive disease. C. dubliniensis shares diagnostic characteristics with C. albicans, as germ tube- and chlamydospore-production, and it is generally misclassified as C. albicans by standard diagnostic procedures. Several recent studies have attempted to elucidate useful phenotypic and genotypic characteristics for separating both species. A large variety of methods have been developed with the aim of facilitating rapid and, accurate identification of this species. These have included differential chromogenic isolation platesculture media, direct immunological tests, and enhanced manual and automated biochemical and enzymatic panels. Chromogenic isolation media, as CHROMagar Candida, demonstrate better detection rates than traditional media, and allow the presumptive identification of C. dubliniensis by means of colony color (dark-green colonies). API 20 C AUX system is considered a reference method, but ID 32 C strip, the VITEK Yeast Biochemical Card and the VITEK 2 ID-YST system correctly identify most C. dubliniensis isolates, being the latter the most accurate. Spectroscopic methods, such as Fourier transformed-infrared spectroscopy, offer potential advantages. However, many authors consider that standard methods for differentiation of Candida species are time-consuming, often insensitive and can fail to distinguish C. dubliniensis. To overcome these low sensitivity, poor specificity and intolerable delay,drawbacks, molecular tools have been developed to discriminate C. dubliniensis, and particularly those based on the polymerase chain reaction. But, molecular tools prove difficult and too complex for routine use in the clinical laboratory setting and new developments are necessary. Moreover, an increased resistance to antifungal drugs has been described. Although preliminary studies indicate that most strains of C. dubliniensis are susceptible to antifungal agents, fluconazole-resistant strains have been detected. Furthermore, fluconazole-resistant strains are easily derived in vitro, showing an increased expression of multidrug resistance transporters, as MDR1.

Development of a radiographic index to assess the tarsal involvement in patients with spondyloarthropathies

OBJECTIVE

To develop and test an index to evaluate the radiographic changes that occur in the tarsus and adjacent areas of the foot in patients with spondyloarthropathies (SpA).

METHODS

The spondyloarthropathy tarsal radiographic index (SpA-TRI) was developed in three consecutive steps: (a) detection of descriptors after reviewing 70 radiographic files; (b) descriptor gradation and subsequent modifications performed by a consensus committee, and (c) interobserver variability assessed by three blinded and independent observers on 272 radiographs: anteroposterior 118, lateral 90, oblique 64 from 121 patients with SpA, and intraobserver variability on 75 radiographs from 25 patients with SpA. Statistical analysis included percentage of agreement and kappa test. SpA-TRI score ranges from 0 to 4 (0=normal; 1=osteopenia or suspicious findings; 2=definite joint space narrowing, bony erosion(s), periosteal whiskering, or enthesophyte(s) in the plantar fascia or Achilleal tendon attachments; 3=para-articular enthesophyte(s); 4=bony ankylosis (joint space fusion or complete bridging)).

RESULTS

Complete agreement for every evaluation was >40%, and discordance >1 grade was <15%. The kappa scores among the three observers were acceptable for all the single projections: oblique (0.52, 0.36, 0.35), lateral (0.50, 0.42, 0.56), and anteroposterior (0.40, 0.41, 0.21) views. The combination of lateral and oblique views achieved the highest concordance rates (0.72, 0.33, 0.66), surpassing that of the three projections altogether (0.34, 0.58, 0.37). In every case the concordance was comparable with that of sacroiliac joints (0.47, 0.41, 0.34); intraobserver concordance showed a similar trend.

CONCLUSION

The SpA-TRI is an index that includes the most prominent features of tarsal disease and adjacent areas of the foot in SpA and grades them accordingly, it has an adequate reproducibility, and is suitable for use with two or more projections, preferably the combination of oblique and lateral.

Methylphenidate bioavailability from two extended-release formulations

OBJECTIVE

The objective of these studies was to compare the rate and extent of absorption of d,l-threo-methylphenidate (MPH) from two extended-release products--a capsule formulation containing coated beads and an OROS tablet formulation--in healthy male and female subjects under fasted conditions.

MATERIALS

Metadate CD (methylphenidate HCl, USP) Extended-Release Capsules and Concerta (methylphenidate hydrochloride) Extended-Release Tablets.

METHODS

Two studies were conducted: (1) A single dose, randomized, two-way crossover study in 36 adults comparing a 20 mg capsule and an 18 mg tablet, and (2) a single dose, randomized, four-way crossover study in 24 adults comparing 2 x 20 mg capsules, one 36 mg tablet, 3 x 20 mg capsules and one 54 mg tablet. Blood samples were collected over 24 hours and MPH plasma concentrations were used to calculate pharmacokinetic parameters for each treatment. Equivalence of pharmacokinetic parameters for comparable doses of the formulations was concluded if the 90% confidence intervals (CI) for the ratio between test and reference means were within the 80-125% equivalence criterion.

RESULTS

Both formulations exhibited biphasic plasma concentration-time profiles and were equivalent in terms of total exposure (AUC(0-last) and AUC(0-infinity)). However, early exposure (AUC(0-4) and AUC(0-6), the first maximum measured plasma concentration (C(max-1), and early plasma MPH concentrations (1.5, 3 and 4 hours) were greater with the capsule formulation, while later plasma MPH concentrations (8, 10 and 12 hours) were greater with the tablet formulation (the CIs were outside the 80-125% required for equivalence and p < 0.001 for all). Similar results were obtained whether or not the data were normalized for the difference in total dose.

CONCLUSIONS

The two formulations are not bioequivalent. The capsule fonnulation produces greater exposure to MPH and higher MPH concentrations during the first 6 hours following dosing. MPH is frequently used in school children, and this period would correspond to a major part of the school day.

Chemical isomerism as a key to explore free-energy landscapes in disordered matter

The effects of a minor chemical modification on the microscopic structure of a material in its glass and crystal phases are investigated by the concurrent use of neutron diffraction and computer simulation. Significant changes in short-, intermediate-, and long-range order are found, resulting from the change in molecular structure. These differences are explainable by a shift in the balance between directional and excluded-volume interactions.

Dislocation emission around nanoindentations on a (001) fcc metal surface studied by scanning tunneling microscopy and atomistic simulations

We present a combined study by scanning tunneling microscopy and atomistic simulations of the emission of dissociated dislocation loops by nanoindentation on a (001) fcc surface. The latter consist of two stacking-fault ribbons bounded by Shockley partials and a stair-rod dislocation. These dissociated loops, which intersect the surface, are shown to originate from loops of interstitial character emitted along the <110> directions and are usually located at hundreds of angstroms away from the indentation point. Simulations reproduce the nucleation and glide of these dislocation loops.

Structure-activity relationship of in vitro antiviral and cytotoxic activity of semisynthetic analogues of scopadulane diterpenes

Fourteen semisynthetic compounds derived from the natural scopadulane-type diterpenes thyrsiflorin A (4), B (5), and C (6), including several precursors, have been examined in vitro for their antiherpetic activity against Herpes simplex virus type II (HSV-2) and cytotoxicity against two human tumor cell lines. Four of these compounds showed moderate antiherpetic activity, but none of them exhibited a significant cytotoxicity against the cell lines used. Some structure-activity relationships have been identified for the antiviral activity in these scopadulane derivatives as well as important structural features for the cytotoxic activity.

Transplanted long-term cultured pre-BI cells expressing calpastatin are resistant to B cell receptor-induced apoptosis

Long-term cultured pre-B cells are able to differentiate into immunoglobulin (Ig)M-positive B cells (IgM(+) cells) when transplanted into severe combined immunodeficient (SCID) mice. Based on previous studies, here we report the development of a reconstitution assay in nonobese diabetic/SCID (NOD/SCID) mice using pre-B cells, which allows us to study the role of calpains (calcium-activated endopeptidases) during B cell development as well as in B cell clonal deletion. Using this model, we show that calpastatin (the natural inhibitor of calpains) inhibits B cell receptor-induced apoptosis in IgM(+) cells derived from transplanted mice. We thus hypothesize an important function for calpain in sculpting the B cell repertoire.

Matrix metalloproteinase expression after human cardioembolic stroke: temporal profile and relation to neurological impairment

BACKGROUND AND PURPOSE

Uncontrolled expression of matrix metalloproteinases (MMPs) can result in tissue injury and inflammation. In animal models of cerebral ischemia, the expression of MMP-2 and MMP-9 was significantly increased. However, their role in human stroke in vivo remains unknown. Therefore, we sought to determine the temporal profile of MMP expression in patients with acute ischemic stroke and to investigate its relationship to stroke severity, location of arterial occlusion, and total infarct volume.

METHODS

Serial MMP-2 and MMP-9 determinations were made in 39 patients with cardioembolic strokes that involved the middle cerebral artery territory by means of enzyme-linked immunosorbent assay. Blood samples, transcranial Doppler recordings, and National Institutes of Health Stroke Scale (NIHSS) scores were obtained at baseline and at 12, 24, and 48 hours after stroke onset. Infarct volume was measured with CT scanning at 48 hours.

RESULTS

No correlation was found between MMP-2 and NIHSS score at any time point, although a close relation appeared between mean MMP-9 and final NIHSS score (r=0.486, P=0.002). MMP-9 value was the only factor associated with the final NIHSS score in the multiple logistic regression model (OR 4.54, 95% CI 1.5 to 13.75). A cut-point of MMP-9 142.18 ng/mL had a positive predictive value of 94.4% to assess a patient's NIHSS (<8 or >/=8) by the end of the study. Final MMP-2 and MMP-9 levels were significantly lower when recanalization occurred (528+/-144.3 versus 681.4+/-239.2 ng/mL, P=0.031 for MMP-2; 110.2+/-100.9 versus 244.8+/-130 ng/mL, P=0.004 for MMP-9). A positive correlation was found between mean MMP-9 and infarct volume (r=0.385, P=0.022).

CONCLUSIONS

MMPs are involved in the acute phase of human ischemic stroke. MMP-9 levels are associated with neurological deficit, middle cerebral artery occlusion, and infarct volume.

A cutaneous gene therapy approach to human leptin deficiencies: correction of the murine ob/ob phenotype using leptin-targeted keratinocyte grafts

Leptin deficiency produces a phenotype of obesity, diabetes, and infertility in the ob/ob mouse. In humans, leptin deficiency occurs in some cases of congenital obesity and in lipodystrophic disorders characterized by reduced adipose tissue and insulin resistance. Cutaneous gene therapy is considered an attractive potential method to correct circulating protein deficiencies, since gene-transferred human keratinocytes can produce and secrete gene products with systemic action. However, no studies showing correction of a systemic defect have been reported. We report the successful correction of leptin deficiency using cutaneous gene therapy in the ob/ob mouse model. As a feasibility approach, skin explants from transgenic mice overexpressing leptin were grafted on immunodeficient ob/ob mice. One month later, recipient mice reached body weight values of lean animals. Other biochemical and clinical parameters were also normalized. In a second human gene therapy approach, a retroviral vector encoding both leptin and EGFP cDNAs was used to transduce HK and, epithelial grafts enriched in high leptin-producing HK were transplanted to immunosuppressed ob/ob mice. HK-derived leptin induced body weight reduction after a drop in blood glucose and food intake. Leptin replacement through genetically engineered HK grafts provides a valuable therapeutic alternative for permanent treatment of human leptin deficiency conditions.

Reentrant miscibility in fluids with spherical interactions

We have obtained the closed-loop fluid-fluid immiscibility in the phase diagram of a binary mixture with interactions with spherical symmetry. That topology appears when a short-range attractive interaction is considered between unlike pair molecules. We present "exact" results obtained from Monte Carlo simulation on different ensembles and results from the application of a first-order perturbation theory.

[Hypopharynx and larynx basaloid squamous carcinoma: our experience with 6 cases]

INTRODUCTION

Basaloid squamous carcinoma (BSC) of the head and neck is an uncommon, recently described variant of epidermoid carcinoma. BSC appears biologically with a greater propensity to local aggressiveness and metastatic potential than the conventional type.

OBJECTIVES

To determine the incidence of BSC of the larynx and hypopharynx in our area, and to evaluate its behavior and prognosis.

PATIENTS & METHODS

272 cases of squamous carcinoma of the larynx and hypopharynx were reviewed and 6 diagnosis of BSC were made, corresponding to 6 tumors in 5 patients. Their clinical records were analyzed. An immunohistochemical study was performed, including antibodies against cytokeratins (CK 7, CK 8, CK 19, CK 20, CK 1, 10, 5, 14, y CK 10), epithelial markers (EMA, CEA, Ber-EP4), vimentin and three neuroendocrine markers: neuron-specific enolase, chromogranin and synaptophisin. Bcl-2 expression was also investigated.

RESULTS

Most tumors were supraglottic. 5 out of 6 tumors were clinically benign, without any metastases or recurrence after exclusive surgical resection and a follow-up ranging 42 to 142 months. We detected a trend toward a primitive pattern of keratin expression. All tumors were stained with EMA and CEA MoAbs, but we could not find Ber-EP4 nor endocrine markers staining in any of them. However, BCL-2 expression was widely found in 4 out of 5 tumors immunostained.

CONCLUSION

It seems to be a progressive dedifferentiation of the basaloid cell component, probably a subpopulation with more primitive features responsible of the aggressiveness reported in the literature. However, the surprising good prognosis in most of our cases makes necessary more studies and wider series to confirm our data.

A role for chemokine receptor transactivation in growth factor signaling

Complex cell responses require the integration of signals delivered through different pathways. We show that insulin-like growth factor (IGF)-I induces specific transactivation of the Gi-coupled chemokine receptor CCR5, triggering its tyrosine phosphorylation and Galpha recruitment. This transactivation occurs via a mechanism involving transcriptional upregulation and secretion of RANTES, the natural CCR5 ligand. CCR5 transactivation is an essential downstream signal in IGF-I-induced cell chemotaxis, as abrogation of CCR5 function with a transdominant-negative KDELccr5A32 mutant abolishes IGF-I-induced migration. The relevance of this transactivation pathway was shown in vivo, as KDELccr5A32 overexpression prevents invasion by highly metastatic tumor cells; conversely, RANTES overexpression confers built-in invasive capacity on a non-invasive tumor cell line. Our results suggest that this extracellular growth factor-chemokine network represents a general mechanism connecting tumorigenesis and inflammation.

[Heart failure in Argentina]

Heart failure is a common and costly clinical entity that implies high morbidity and mortality. The aim of this study was to establish the impact of the heart failure syndrome in our country. We analyzed: 1) the data-base of vital statistics from the National Program of Health Statistics, Ministry of Health, between 1980 and 1997, 2) the registers from two national surveys on heart failure patients performed by the Argentine Society of Cardiology and the Argentine Council of Residents in Cardiology. Cardiovascular syndromes have constituted the first cause of death in our country for the last twenty years. Among these, heart failure represents the most frequent entity. From 1980 to 1997 a progressive reduction of 31% in the rate of cardiovascular mortality was observed. From 1990 to 1997, a decrease in the mortality rate due to heart failure of 22.4% was registered. Age and sex adjusted mortality from heart failure suffered a steady increase in older groups, specially above 65 years of age. Hospital discharge data showed that heart failure and cerebrovascular illness are the highest prevalent entities. National surveys on heart failure demonstrate a high prevalence of hypertension, as an associated risk factor, and non compliance with the medication and diet as causes of decompensation. A trend towards an increase in pharmacological prescriptions was also observed.

Acute renal failure as presentation of a Burkitt's lymphoma

Acute renal failure due to diffuse renal infiltration is rarely the presenting manifestation of non-Hodgkin's lymphoma. We report a patient with acute renal failure secondary to diffuse bilateral renal infiltration by a Burkitt's lymphoma. The presence of bilateral renal enlargement, an elevated serum lactate dehydrogenase (LDH), and lymphopenia should suggest the diagnosis, which can be confirmed by renal biopsy.

[Mucoepidermoid carcinoma of the nasal vestibulum]

Mucoepidermoid carcinoma is a malignant epithelial tumor, with a mucosecretor component that is exceptional in the upper airways. It seems to be a kind of immunity in this area to the development of this tumors. In the review of the literature we only have found three cases in the nasal cavity. We present the case of a 18th years old woman with a tumor in the right nostril for two months. Several biopsy were required to achieve its histopathological diagnosis as a high malignant mucoepidermoid carcinoma. Radical surgery over the tumor and metastasis was performed but the case has a bad prognosis. The prognosis of the mucoepidermoid carcinoma depends on the histological grade, the early diagnosis and the surgical treatment which has to be so radical as possible to obtain free tumors limits.

Multiple endocrine involvement in two pediatric patients with Kearns-Sayre syndrome

We present 2 cases of progressively severe Kearns-Sayre syndrome (KSS) with multisystemic affectation and atypical endocrine and cutaneous features, a 16-year-old patient (case 1) and a 5-year-old patient (case 2). Endocrine studies showed high glucose and glycohemoglobin concentrations with normal pancreatic reserve and low values of ACTH, cortisol, LH and FSH in case 1. Normal ACTH values with low concentrations of cortisol and PTH were observed in case 2. Southern blot analysis and PCR amplification revealed the presence of a deletion of approximately 6.7 kb in the mitochondrial DNA of both patients. Endocrinological studies suggest that adrenal insufficiency may be an additional feature of KSS that worsens the clinical evolution of the patients. In spite of a normal pancreatic reserve, insulin therapy should be considered in patients with diabetes mellitus of mitochondrial origin.

DNA polymerase mu (Pol mu), homologous to TdT, could act as a DNA mutator in eukaryotic cells

A novel DNA polymerase has been identified in human cells. Human DNA polymerase mu (Pol mu), consisting of 494 amino acids, has 41% identity to terminal deoxynucleotidyltransferase (TdT). Human Pol mu, overproduced in Escherichia coli in a soluble form and purified to homogeneity, displays intrinsic terminal deoxynucleotidyltransferase activity and a strong preference for activating Mn(2+) ions. Interestingly, unlike TdT, the catalytic efficiency of polymerization carried out by Pol mu was enhanced by the presence of a template strand. Using activating Mg(2+) ions, template-enhanced polymerization was also template-directed, leading to the preferred insertion of complementary nucleotides, although with low discrimination values. In the presence of Mn(2+) ions, template-enhanced polymerization produced a random insertion of nucleotides. Northern-blotting and in situ analysis showed a preferential expression of Pol mu mRNA in peripheral lymphoid tissues. Moreover, a large proportion of the human expressed sequence tags corresponding to Pol mu, present in the databases, derived from germinal center B cells. Therefore, Pol mu is a good candidate to be the mutator polymerase responsible for somatic hyper- mutation of immunoglobulin genes.

First diastereoselective synthesis of (-)-methyl thyrsiflorin A, (-)-methyl thyrsiflorin B acetate, and (-)-thyrsiflorin C

An efficient procedure for the synthesis of scopadulan diterpenes, using (+)-podocarp-8(14)-en-13-one 13 as starting material, is reported. This procedure has been used for the diastereoselective synthesis of (-)-methyl thyrsiflorin A (8), (-)-methyl thyrsiflorin B acetate (9), and (-)-thyrsiflorin C (7). Key steps in our strategy are the intramolecular cyclopropanation of diazoketone 19 and the regioselective cleavage of the cyclopropane ring.

DeltahGHR, a novel biosafe cell surface-labeling molecule for analysis and selection of genetically transduced human cells

We describe a new selectable marker for retroviral transduction and selection of human and murine cells. The molecule expressed on the cell surface of the transduced population is a truncated version of human growth hormone receptor (deltahGHR), capable of ligand (hGH) binding, but devoid of the domains involved in signal triggering. We demonstrate that the engineered molecule is stably expressed in the target cells as an inert protein unable to trigger proliferation or to rescue the cells from apoptosis after ligand binding. This new marker will probably have a wide application spectrum, since hGHR in the human adult is highly expressed only in liver cells, and lower levels have been reported in certain lymphocyte cell populations. The deltahGHR label has high biosafety potential, as it belongs to a well-characterized hormonal system that is nonessential in adults, and there is extensive clinical experience with hGH administration in humans. This record allows us to hypothesize the lack of relevant clinical consequences resulting from massive transgene expression caused by successful replacement of a large tissue with genetically transduced cells. We take advantage of the differential binding properties of several monoclonal antibodies (MAbs) in describing a cell rescue method in which the antibody used to select deltahGHR-transduced cells is eluted by competition with hGH or, alternatively biotinylated hGH is used to capture tagged cells. In the latter system, the final purified population would be recovered free of attached antibodies in hGH (a substance approved for human use)-containing medium, providing additional biosafety relative to currently existing methods that rely on the use of murine MAb to rescue genetically labeled cells.