232 research outputs found
Mathematical Modelling of Optical Coherence Tomography
In this chapter a general mathematical model of Optical Coherence Tomography
(OCT) is presented on the basis of the electromagnetic theory. OCT produces
high resolution images of the inner structure of biological tissues. Images are
obtained by measuring the time delay and the intensity of the backscattered
light from the sample considering also the coherence properties of light. The
scattering problem is considered for a weakly scattering medium located far
enough from the detector. The inverse problem is to reconstruct the
susceptibility of the medium given the measurements for different positions of
the mirror. Different approaches are addressed depending on the different
assumptions made about the optical properties of the sample. This procedure is
applied to a full field OCT system and an extension to standard (time and
frequency domain) OCT is briefly presented.Comment: 28 pages, 5 figures, book chapte
Dirac Equation with Spin Symmetry for the Modified P\"oschl-Teller Potential in -dimensions
We present solutions of the Dirac equation with spin symmetry for vector and
scalar modified P\"oschl-Teller potential within framework of an approximation
of the centrifugal term. The relativistic energy spectrum is obtained using the
Nikiforov-Uvarov method and the two-component spinor wavefunctions are obtain
are in terms of the Jacobi polynomials. It is found that there exist only
positive-energy states for bound states under spin symmetry, and the energy
levels increase with the dimension and the potential range parameter .Comment: 9 pages and 1tabl
Pathogen- and Host-Directed Antileishmanial Effects Mediated by Polyhexanide (PHMB)
BACKGROUND:Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed. METHODOLOGY/PRINCIPAL FINDINGS:Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide), a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major) via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN). PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB. CONCLUSIONS:Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators
Isothiocyanates induce oxidative stress and suppress the metastasis potential of human non-small cell lung cancer cells
<p>Abstract</p> <p>Background</p> <p>Isothiocyanates are natural compounds found in consumable cruciferous vegetables. They have been shown to inhibit chemical carcinogenesis by a wide variety of chemical carcinogens in animal models. Recent studies have also shown that isothiocyanates have antitumor activity, inhibiting the growth of several types of cultured human cancer cells. Our previous study showed that PEITC inhibited human leukemia cells growth by inducing apoptosis. However, the effect of isothiocyanates on lung cancer cell metastasis has not been studied. In the present study, we investigated the inhibitory effects of BITC and PEITC on metastatic potential of highly metastatic human lung cancer L9981 cells.</p> <p>Methods</p> <p>Cell migration and invasion were measured by wound healing assay and transwell chemotaxis assay. Expression of metastasis-related genes was assessed by quantitative RT-PCR and Western blotting. The mechanisms of action were evaluated by flow cytometry, reporter assay and Western blotting.</p> <p>Results</p> <p>Our data showed that both BITC and PEITC inhibited L9981 cell growth in a dose-dependent manner, the IC50 values were 5.0 and 9.7 ΞΌM, respectively. Cell migrations were reduced to 8.1% and 16.5% of control, respectively; and cell invasions were reduced to 2.7% and 7.3% of control, respectively. Metastasis-related genes MMP-2, Twist and Ξ²-catenin were also modulated. BITC and PEITC inhibited cell survival signaling molecules Akt and NFΞΊB activation. Moreover, BITC and PEITC increased ROS generation and caused GSH depletion. Pretreatment with NAC blocked BITC and PEITC induced ROS elevation and NFΞΊB inhibition.</p> <p>Conclusion</p> <p>Our results indicated that BITC and PEITC suppress lung cancer cell metastasis potential by modulation of metastasis-related gene expression, inhibition of Akt/NFΞΊB pathway. Induction of oxidative stress may play an important role.</p
Phase I dose-escalation study to determine the safety, pharmacokinetics and pharmacodynamics of brivanib alaninate in combination with full-dose cetuximab in patients with advanced gastrointestinal malignancies who have failed prior therapy
Influence of the Temperature and the Genotype of theΒ HSP90AA1Β Gene over Sperm Chromatin Stability in Manchega Rams
The present study addresses the effect of heat stress on males' reproduction ability. For that, we have evaluated the sperm DNA fragmentation (DFI) by SCSA of ejaculates incubated at 37Β°C during 0, 24 and 48 hours after its collection, as a way to mimic the temperature circumstances to which spermatozoa will be subject to in the ewe uterus. The effects of temperature and temperature-humidity index (THI) from day 60 prior collection to the date of semen collection on DFI were examined. To better understand the causes determining the sensitivity of spermatozoa to heat, this study was conducted in 60 males with alternative genotypes for the SNP G/Cβ660 of the HSP90AA1 promoter, which encode for the Hsp90Ξ± protein. The Hsp90Ξ± protein predominates in the brain and testis, and its role in spermatogenesis has been described in several species. Ridge regression analyses showed that days 29 to 35 and 7 to 14 before sperm collection (bsc) were the most critical regarding the effect of heat stress over DFI values. Mixed model analyses revealed that DFI increases over a threshold of 30Β°C for maximum temperature and 22 for THI at days 29 to 35 and 7 to 14 bsc only in animals carrying the GGβ660 genotype. The period 29β35 bsc coincide with the meiosis I process for which the effect of the Hsp90Ξ± has been described in mice. The period 7β14 bsc may correspond with later stages of the meiosis II and early stages of epididymal maturation in which the replacement of histones by protamines occurs. Because of GGβ660 genotype has been associated to lower levels of HSP90AA1 expression, suboptimal amounts of HSP90AA1 mRNA in GGβ660 animals under heat stress conditions make spermatozoa DNA more susceptible to be fragmented. Thus, selecting against the GGβ660 genotype could decrease the DNA fragmentation and spermatozoa thermal susceptibility in the heat season, and its putative subsequent fertility gainsPublishe
Gene Expression Rhythms in the Mussel Mytilus galloprovincialis (Lam.) across an Annual Cycle
Seasonal environmental changes may affect the physiology of Mytilus
galloprovincialis (Lam.), an intertidal filter-feeder bivalve
occurring commonly in Mediterranean and Atlantic coastal areas. We investigated
seasonal variations in relative transcript abundance of the digestive gland and
the mantle (gonads) of males and females. To identify gene expression trends
β in terms of relative mRNA abundance- we used a medium-density cDNA
microarray (1.7 K probes) in dual-color competitive hybridization analyses.
Hierarchical clustering of digestive gland microarray data showed two main
branches, distinguishing profiles associated with the βhotβ months
(MayβAugust) from the other months. Genes involved in chitin metabolism,
associated with mussel nutrition and digestion showed higher mRNA levels during
summer. Moreover, we found different gene transcriptomic patterns in the
digestive glands of males when compared to females, during the four stages of
mussel gonadal development. Microarray data from gonadal transcripts also
displayed clear patterns during the different developmental phases respect to
the resting period (stage I) with peak relative mRNA abundance at the ripe phase
(stage III) for both sexes. These data showed a clear temporal pattern in
transcriptomic profiles of mussels sampled over an annual cycle. Physiological
response to thermal variation, food availability, and reproductive status across
months may contribute to variation in relative mRNA abundance
Immunohistochemical discrimination of wild-type EGFR from EGFRvIII in fixed tumour specimens using anti-EGFR mAbs ICR9 and ICR10
Background:The human epidermal growth factor receptor (EGFR) is an important therapeutic target in oncology, and three different types of EGFR inhibitors have been approved for the treatment of cancer patients. However, there has been no clear association between the expression levels of EGFR protein in the tumours determined by the FDA-approved EGFR PharmDx kit (Dako) or other standard anti-EGFR antibodies and the response to the EGFR inhibitors.Method:In this study, we investigated the potential of our anti-EGFR monoclonal antibodies (mAbs; ICR9, ICR10, ICR16) for immunohistochemical diagnosis of wild-type EGFR and/or the type-III deletion mutant form of EGFR (EGFRvIII) in formalin-fixed, paraffin-embedded human tumour specimens.Results:We found that the anti-EGFR mAb in the EGFR PharmDx kit stained both wild-type and EGFRvIII-expressing cells in formalin-fixed, paraffin-embedded sections. This pattern of EGFR immunostaining was also found with our anti-EGFR mAb ICR16. In contrast, mAbs ICR10 and ICR9 were specific for the wild-type EGFR.Conclusion:We conclude that mAbs ICR9 and ICR10 are ideal tools for investigating the expression patterns of wild-type EGFR protein in tumour specimens using immunohistochemistry, and to determine their prognostic significance, as well as predictive value for response to therapy with EGFR antibodies.British Journal of Cancer advance online publication, 7 February 2012; doi:10.1038/bjc.2012.27 www.bjcancer.com
Developmental Hippocampal Neuroplasticity in a Model of Nicotine Replacement Therapy during Pregnancy and Breastfeeding
The influence of developmental nicotine exposure on the brain represents an important health topic in light of the popularity of nicotine replacement therapy (NRT) as a smoking cessation method during pregnancy.In this study, we used a model of NRT during pregnancy and breastfeeding to explore the consequences of chronic developmental nicotine exposure on cerebral neuroplasticity in the offspring. We focused on two dynamic lifelong phenomena in the dentate gyrus (DG) of the hippocampus that are highly sensitive to the environment: granule cell neurogenesis and long-term potentiation (LTP).Pregnant rats were implanted with osmotic mini-pumps delivering either nicotine or saline solutions. Plasma nicotine and metabolite levels were measured in dams and offspring. Corticosterone levels, DG neurogenesis (cell proliferation, survival and differentiation) and glutamatergic electrophysiological activity were measured in pups.Juvenile (P15) and adolescent (P41) offspring exposed to nicotine throughout prenatal and postnatal development displayed no significant alteration in DG neurogenesis compared to control offspring. However, NRT-like nicotine exposure significantly increased LTP in the DG of juvenile offspring as measured in vitro from hippocampal slices, suggesting that the mechanisms underlying nicotine-induced LTP enhancement previously described in adult rats are already functional in pups.These results indicate that synaptic plasticity is disrupted in offspring breastfed by dams passively exposed to nicotine in an NRT-like fashion
Attachment, infidelity, and loneliness in college students involved in a romantic relationship: the role of relationship satisfaction, morbidity and prayer for partner
This study examined the mediating effects of relationship satisfaction, prayer
for a partner, and morbidity in the relationship between attachment and loneliness, infidelity
and loneliness, and psychological morbidity and loneliness, in college students
involved in a romantic relationship. Participants were students in an introductory course on
family development. This study examined only students (n = 345) who were involved in a
romantic relationship. The average age of participants was 19.46 (SD = 1.92) and 25 %
were males. Short-form UCLA Loneliness Scale (ULS-8), (Hays and DiMatteo in J Pers
Assess 51:69β81, doi:10.1207/s15327752jpa5101_6, 1987); Relationship Satisfaction
Scale (Funk and Rogge in J Fam Psychol 21:572β583, doi:10.1037/0893-3200.21.4.572,
2007); Rotterdam Symptom Checklist (De Haes et al. in Measuring the quality of life of
cancer patients with the Rotterdam Symptom Checklist (RSCL): a manual, Northern
Centre for Healthcare Research, Groningen, 1996); Prayer for Partner Scale, (Fincham
et al. in J Pers Soc Psychol 99:649β659, doi:10.1037/a0019628, 2010); Infidelity Scale,
(Drigotas et al. in J Pers Soc Psychol 77:509β524, doi:10.1037/0022-3514.77.3.509, 1999);
and the Experiences in Close Relationship Scale-short form (Wei et al. in J Couns Psychol
52(4):602β614, doi:10.1037/0022-0167.52.4.602, 2005). Results showed that relationship
satisfaction mediated the relationship between avoidance attachment and loneliness and
between infidelity and loneliness. Physical morbidity mediated the relationship between
anxious attachment and psychological morbidity. Psychological morbidity mediated the
relationship between anxious attachment and physical morbidity. The present results
expand the literature on attachment by presenting evidence that anxious and avoidant partners experience loneliness differently. Implications for coupleβs therapy are addressed.
Future research should replicate these results with older samples and married couples.Acknowledgments This research was supported by Grant Number 90FE0022 from the United States
Department of Health and Human Services awarded to the last author
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