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Publication
Journal: Human Molecular Genetics
August/19/2007
Abstract
The 'vanishing bone' or inherited osteolysis/arthritis syndromes represent a heterogeneous group of skeletal disorders characterized by mineralization defects of affected bones and joints. Differing in anatomical distribution, severity and associated syndromic features, gene identification in each 'vanishing bone' disorder should provide unique insights into genetic/molecular pathways contributing to the overall control of skeletal growth and development. We previously described and then demonstrated that the novel autosomal recessive osteolysis/arthritis syndrome, multicentric osteolysis with arthritis (MOA) (MIM #605156), was caused by inactivating mutations in the MMP2 gene [Al Aqeel, A., Al Sewairi, W., Edress, B., Gorlin, R.J., Desnick, R.J. and Martignetti, J.A. (2000) Inherited multicentric osteolysis with arthritis: A variant resembling Torg syndrome in a Saudi family. Am. J. Med. Genet., 93, 11-18.]. These in vivo results were counterintuitive and unexpected since previous in vitro studies suggested that MMP-2 overexpression and increased activity, not deficiency, would result in the bone and joint features of MOA. The apparent lack of a murine model [Itoh, T., Ikeda, T., Gomi, H., Nakao, S., Suzuki, T. and Itohara, S. (1997) Unaltered secretion of beta-amyloid precursor protein in gelatinase A (matrix metalloproteinase 2)-deficient mice. J. Biol. Chem., 272, 22389-22392.] has hindered studies on disease pathogenesis and, more fundamentally, in addressing the paradox of how functional loss of a single proteolytic enzyme results in an apparent increase in bone loss. Here, we report that Mmp2-/- mice display attenuated features of human MOA including progressive loss of bone mineral density, articular cartilage destruction and abnormal long bone and craniofacial development. Moreover, these changes are associated with markedly and developmentally restricted decreases in osteoblast and osteoclast numbers in vivo. Mmp2-/- mice have approximately 50% fewer osteoblasts and osteoclasts than control littermates at 4 days of life but these differences have nearly resolved by 4 weeks of age. In addition, despite normal cell numbers in vivo at 8 weeks of life, Mmp2-/- bone marrow cells are unable to effectively support osteoblast and osteoclast growth and differentiation in culture. Targeted inhibition of MMP-2 using siRNA in human SaOS2 and murine MC3T3 osteoblast cell lines resulted in decreased cell proliferation rates. Taken together, our findings suggest that MMP-2 plays a direct role in early skeletal development and bone cell growth and proliferation. Thus, Mmp2-/- mice provide a valuable biological resource for studying the pathophysiological mechanisms underlying the human disease and defining the in vivo physiological role of MMP-2.
Publication
Journal: Vaccine
August/19/2003
Abstract
OBJECTIVE
To determine if respiratory syncytial virus (RSV) specific, serum antibody titers correlate with protection against RSV associated-hospitalization at all ages.
METHODS
Participants who were enrolled in a trial to determine the frequency of specific virus infections associated with hospitalization [J. Am. Med. Assoc. 283 (2000) 499] were included in our analysis if they were enrolled from July 1991 to June 1993, had a culture for virus isolation, and provided blood samples at hospitalization and 14-60 days later. RSV infection was defined by a positive culture and/or serology. Microneutralization, ELISA to the fusion (F) protein and Western blot were the serological assays that were used to determine correlates of immunity.
RESULTS
One hundred and seventy-five individuals, 1 month to 89 years old, out of 538 patients hospitalized with an acute respiratory infection met the criteria for analysis. RSV associated-hospitalization occurred in 11 (40.7%) of 27 infants (<1 year), 8 (38.1%) of 21 young children (1 to <5 years), and 15 (11.8%) of 127 children and adults >> or =5 years). At the time of hospitalization, geometric mean neutralizing antibody titers (log(2)) to RSV/A and RSV/B, and geometric mean binding antibody titer (log(2)) to F protein were significantly higher in patients with non-RSV associated-hospitalization compared to those with RSV associated-hospitalization (RSV/A: 7.9 versus 6.1, P<0.001; RSV/B: 9.4 versus 7.3, P<0.001; ELISA-F, 13.9 versus 12.6, P=0.01). For every 1 log(2) increase in titer of neutralizing antibodies to RSV/A and RSV/B, and binding antibody to F protein there was a significant increase in the likelihood of not having an RSV associated-hospitalization by 22.3, 25, and 24.4% respectively. A minimal protective threshold titer of>> or =6.0 (odds ratio 3.5; 95% CI 1.4-9.1) and>> or =8.0 log(2) (odds ratio 2.9; 95% CI 1.1-7.7) against RSV associated-hospitalization was established for neutralizing antibodies to RSV/A and RSV/B; a threshold titer could not be established for binding antibody to F protein.
CONCLUSIONS
Participants with naturally acquired serum neutralizing antibody levels at least equal to the minimal protective threshold titer were approximately three times more likely not to have an RSV associated-hospitalization. We speculate that achieving a minimal protective threshold antibody titer through active immunization will significantly reduce RSV associated-hospitalization among all ages.
Publication
Journal: International Journal of Audiology
February/28/2007
Abstract
Early clinical findings are reported for subjects implanted with the Vibrant Med-El Soundbridge (VSB) device. The present criteria for the VSB, limiting its application to patients with normal middle ear function, have been extended to include patients with ossicular chain defects. Seven patients with severe mixed hearing loss were implanted with the transducer placed onto the round window. All had undergone previous surgery: six had multiple ossiculoplasties, and one had the VSB crimped on the incus with unsuccessful results. Round window implantation bypasses the normal conductive path and provides amplified input to the cochlea. Post-operative aided thresholds of 30 dB HL were achieved for most subjects, as compared with unaided thresholds ranging from 60-80 dB HL. Aided speech reception thresholds at 50% intelligibility were 50 dB HL, with most subjects reaching 100% intelligibility at conversational levels, while unaided thresholds averaged 80 dB HL, with only one subject reaching 100% intelligibility. These results suggest that round window implantation may offer a viable treatment option for individuals with severe mixed hearing losses who have undergone unsuccessful ossiculoplasties.
Publication
Journal: Audiology and Neuro-Otology
July/7/2005
Abstract
Combined electric and acoustic stimulation (EAS) of the auditory system is a new therapy for patients with severe to profound high- and mid-frequency hearing loss but remaining low-frequency hearing. In a prospective study, 13 patients with low-frequency hearing of better than 60 dB below 1 kHz were implanted with a MED-EL COMBI 40+ cochlear implant. Pure tone thresholds as well as monosyllabic word scores and Hochmair-Schulz-Moser sentences in quiet and in noise were measured with hearing aids, cochlear implant alone and in the combined stimulation mode (EAS) in the same ear. Hearing could be partially preserved in 11 out of the 13 patients. All patients scored significantly higher with cochlear implant alone than with hearing aids. Seven patients scored higher in the EAS mode than with cochlear implant alone for sentences in noise, 4 remained unchanged, and 2 could not use EAS. Synergistic effects of EAS were most prominent for hearing in noise with increases of up to 72% as compared to cochlear implant alone.
Publication
Journal: Magnetic Resonance in Medicine
January/31/2001
Abstract
In a study of interregional variation of the longitudinal relaxation rate (R(1)) in human brain at 3 T, R(1) maps were acquired from 12 healthy adults using a multi-slice implementation of the T one by multiple readout pulses (TOMROP) sequence. Mean R(1) values were obtained from the prefrontal cortex (0.567 +/- 0.020 sec(-1)), caudate head (0.675 +/- 0.019 sec(-1)), putamen (0.749 +/- 0.023 sec(-1)), substantia nigra (0.873 +/- 0.037 sec(-1)), globus pallidus (0.960 +/- 0.034 sec(-1)), thalamus (0.822 +/- 0.027 sec(-1)), and frontal white matter (1.184 +/- 0.057 sec(-1)). For gray matter regions other than the thalamus, R(1) showed a strong correlation (r = 0.984, P < 0.0001) with estimated regional nonheme iron concentrations ([Fe]). These R(1) values also showed a strong correlation (r = 0.976, P < 0.0001) with estimates of 1/f(w) obtained from MRI relative proton density measurements, where f(w) represents tissue water content. When white matter is included in the consideration, 1/f(w) is a better predictor of R(1) than is [Fe]. An analysis based on the fast-exchange two-state model of longitudinal relaxation suggests that interregional differences in f(w) account for the majority of the variation of R(1) across gray matter regions. Magn Reson Med 45:71-79, 2001.
Publication
Journal: Neurology
May/15/2013
Abstract
OBJECTIVE
To assess efficacy and safety of trigeminal neurostimulation with a supraorbital transcutaneous stimulator (Cefaly, STX-Med., Herstal, Belgium) in migraine prevention.
METHODS
This was a double-blinded, randomized, sham-controlled trial conducted at 5 Belgian tertiary headache clinics. After a 1-month run-in, patients with at least 2 migraine attacks/month were randomized 1:1 to verum or sham stimulation, and applied the stimulator daily for 20 minutes during 3 months. Primary outcome measures were change in monthly migraine days and 50% responder rate.
RESULTS
Sixty-seven patients were randomized and included in the intention-to-treat analysis. Between run-in and third month of treatment, the mean number of migraine days decreased significantly in the verum (6.94 vs 4.88; p = 0.023), but not in the sham group (6.54 vs 6.22; p = 0.608). The 50% responder rate was significantly greater (p = 0.023) in the verum (38.1%) than in the sham group (12.1%). Monthly migraine attacks (p = 0.044), monthly headache days (p = 0.041), and monthly acute antimigraine drug intake (p = 0.007) were also significantly reduced in the verum but not in the sham group. There were no adverse events in either group.
CONCLUSIONS
Supraorbital transcutaneous stimulation with the device used in this trial is effective and safe as a preventive therapy for migraine. The therapeutic gain (26%) is within the range of those reported for other preventive drug and nondrug antimigraine treatments.
METHODS
This study provides Class III evidence that treatment with a supraorbital transcutaneous stimulator is effective and safe as a preventive therapy for migraine.
Publication
Journal: Magnetic Resonance in Medicine
May/16/2001
Abstract
The apparent diffusion tensor (ADT) was measured in excised and fixed spinal cords from myelin-deficient (md) rats and age-matched controls. These data were used to obtain the principal diffusivities of the ADT, and also the scalar invariant parameters _D (averaged principal diffusivity) and A(sigma) (anisotropy index) for four white matter and two gray matter regions. The results for white matter regions showed that the principal diffusivities were significantly higher for md animals, and while the _D was increased in tissue from md animals, the A(sigma) was found to be decreased. Grey matter _D was measured to be between those of white matter from control and md animals, and the A(sigma) was much smaller than that of white matter from both sets of animals, indicating that diffusion in md white matter is more anisotropic than in gray matter. The results show that while myelination is not a prerequisite for diffusion anisotropy, it does influence the magnitude of the observed anisotropy. Magn Reson Med 45:191-195, 2001.
Publication
Journal: Journal of Biological Chemistry
March/17/1994
Abstract
Fc receptor-mediated phagocytosis in mouse macrophages occurs by a tyrosine kinase-dependent pathway (Greenberg, S., Chang, P., and Silverstein, S.C. (1993) J. Exp. Med. 177, 529-534). To identify proteins that are phosphorylated on tyrosine residues during phagocytosis, we used anti-phosphotyrosine antibodies to perform immunoblotting and immunoprecipitation of lysates derived from Fc receptor-stimulated macrophages. Proteins of 26, 30, 35, 37, 40, 43, 47, 56, 60, 68, 83, 116, and 150 kDa displayed enhanced tyrosine phosphorylation during Fc receptor-mediated phagocytosis. Tyrosine phosphorylation of these proteins was not a consequence of actin polymerization since treatment with cytochalasin D did not alter the pattern of Fc receptor-stimulated protein tyrosine phosphorylation. The 68-kDa tyrosine phosphoprotein was identified as paxillin, a cytoskeletal-associated tyrosine kinase substrate previously identified in fibroblasts and shown to localize to focal adhesions (Turner, C.E., Glenney, J.R., and Burridge, K. (1990) J. Cell Biol. 111, 1059-1068). Paxillin colocalized with F-actin beneath nascent phagosomes. In addition to the above proteins detected by anti-phosphotyrosine immunoblotting, the gamma subunit of FcRI and III was shown to undergo tyrosine phosphorylation during Fc receptor-mediated phagocytosis. Of several candidate tyrosine kinases that may be activated during Fc receptor stimulation, p72syk, but not p125FAK, displayed enhanced tyrosine phosphorylation during Fc receptor aggregation. The coordinated tyrosine phosphorylation of the gamma subunit of macrophage Fc receptors, the tyrosine kinase syk, and the cytoskeletal-associated protein, paxillin, may be important steps in integrating signals between Fc receptors and the underlying cytoskeleton.
Publication
Journal: American Journal of Medical Genetics, Part B, Neuropsychiatric Genetics
January/16/2012
Abstract
The identification of clinical and biological markers of disease in persons at risk for Huntington disease (HD) has increased in efforts to better quantify and characterize the epoch of prodrome prior to clinical diagnosis. Such efforts are critical in the design and implementation of clinical trials for HD so that interventions can occur at a time most likely to increase neuronal survival and maximize daily functioning. A prime consideration in the examination of prodromal individuals is their proximity to diagnosis. It is necessary to quantify proximity so that individual differences in key marker variables can be properly interpreted. We take a data-driven approach to develop an index that can be viewed as a proxy for time to HD diagnosis known as the CAG-Age Product Scaled or CAP(S) . CAP(S) is an observed utility variable computed for all genetically at-risk individuals based on age at study entry and CAG repeat length. Results of a longitudinal receiver operating characteristic (ROC) analysis showed that CAP(S) had a relatively strong ability to predict individuals who became diagnosed, especially in the first 2 years. Bootstrap validation provided evidence that CAP(S) computed on a new sample from the same population could have similar discriminatory power. Cutoffs for the empirical CAP(S) distribution can be used to create a classification for mutation-positive individuals (Low-Med-High), which is, useful for comparison with the naturally occurring mutation-negative Control group. The classification is an improvement over the one currently in use as it is based on observed data rather than model-based estimated values. © 2011 Wiley-Liss, Inc.
Publication
Journal: Molecular Pharmacology
March/4/2002
Abstract
Heme oxygenase-1 (HO-1) is a redox-sensitive inducible protein that provides efficient cytoprotection against oxidative stress. Curcumin, a polyphenolic natural compound that possesses anti-tumor and anti-inflammatory properties, has been reported recently to induce potently HO-1 expression in vascular endothelial cells (Free Rad Biol Med 28:1303-1312, 2000). Here, we extend our previous findings by showing that caffeic acid phenethyl ester (CAPE), another plant-derived phenolic agent, markedly increases heme oxygenase activity and HO-1 protein in astrocytes. The effect seems to be related to the peculiar chemical structures of curcumin and CAPE, because analogous antioxidants containing only portions of these two molecules were totally ineffective. At a final concentration of 30 microM, both curcumin and CAPE maximally up-regulated heme oxygenase activity while promoting marked cytotoxicity at higher concentrations (50-100 microM). Similar results were obtained with Curcumin-95, a mixture of curcuminoids commonly used as a dietary supplement. Incubation of astrocytes with curcumin or CAPE at concentrations that promoted maximal heme oxygenase activity resulted in an early increase in reduced glutathione followed by a significant elevation in oxidized glutathione contents. A curcumin-mediated increase in heme oxygenase activity was not affected by the glutathione precursor and thiol donor N-acetyl-L-cysteine. These data suggest that regulation of HO-1 expression by polyphenolic compounds is evoked by a distinctive mechanism which is not necessarily linked to changes in glutathione but might depend on redox signals sustained by specific and targeted sulfydryl groups. This study identifies a novel class of natural substances that could be used for therapeutic purposes as potent inducers of HO-1 in the protection of tissues against inflammatory and neurodegenerative conditions.
Publication
Journal: Journal of Virology
August/10/2010
Abstract
A subset of HIV-1-infected patients known as elite controllers or suppressors (ES) control the virus naturally. We have previously demonstrated sequence discordance between proviral and plasma gag clones in ES, much of which can be attributed to selective pressure from the host (J. R. Bailey, T. M. Williams, R. F. Siliciano, and J. N. Blankson, J. Exp. Med. 203:1357-1369, 2006). However, it is not clear whether ongoing viral replication continues in ES once the control of viremia has been established or whether selective pressure impacts this evolution. The cytotoxic T-lymphocyte (CTL) response in ES often targets Gag and frequently is superior to that of HIV-1 progressors, partially due to the HLA class I alleles B*57/5801 and B*27, which are overrepresented in ES. We therefore examined longitudinal plasma and proviral gag sequences from HLA-B*57/5801 and -B*27 ES. Despite the highly conserved nature of gag, we observed clear evidence of evolution in the plasma virus, largely due to synonymous substitutions. In contrast, evolution was rare in proviral clones, suggesting that ongoing replication in ES does not permit the significant reseeding of the latent reservoir. Interestingly, there was little continual evolution in CTL epitopes, and we detected de novo CTL responses to autologous viral mutants. Thus, some ES control viremia despite ongoing replication and evolution.
Publication
Journal: Journal of Virology
May/17/2000
Abstract
Changes in the envelope glycoprotein ectodomains of a nonpathogenic simian-human immunodeficiency virus (SHIV-89.6) that was serially passaged in vivo have been shown to be responsible for the increased pathogenicity of the resulting virus, SHIV-KB9 (G. B. Karlsson, et al., J. Exp. Med. 188:1159-1171, 1998). The 12 amino acid changes in the envelope glycoprotein ectodomains resulted in increased chemokine receptor-binding and syncytium-forming abilities. Here we identify the envelope glycoprotein determinants of these properties. A single amino acid change in the gp120 third variable (V3) loop was both necessary and sufficient for the observed increase in the binding of the SHIV-KB9 gp120 glycoprotein to the CCR5 chemokine receptor. The increased syncytium-forming ability of SHIV-KB9 involved, in addition to the V3 loop change, changes in the second conserved (C2) region of gp120 (residue 225) and in the gp41 ectodomain (residues 564 and 567). The C2 and gp41 ectodomain changes influenced syncytium formation in a cooperative manner. Changes in the V1/V2 gp120 variable loops exerted a negative effect on syncytium formation and chemokine receptor binding, supporting a previously described role of these changes in immune evasion. The definition of the passage-associated changes that determine the efficiency of chemokine receptor binding and membrane fusogenicity will allow evaluation of the contribution of these properties to in vivo CD4-positive lymphocyte depletion.
Publication
Journal: Integrative Cancer Therapies
May/8/2006
Abstract
OBJECTIVE
To conduct a systematic review of reasons for and sociodemographic and disease characteristics associated with complementary and alternative medicine (CAM) use in cancer patients.
METHODS
Eligible studies were identified by searching the following databases: Alt Health Watch, AMED, CINAHL, CancerLit, PremMEDLINE, MEDLINE, Pub-Med, Ingenta, EMBASE, and Health Star, as well as reference lists in review articles. Only English-language articles published between 1994 and 2004 were included. Search terms included CAM and oncology/cancer, decision making and CAM and oncology/cancer, treatment decision making and CAM and oncology/cancer, and health care choices and CAM and oncology/cancer.
RESULTS
Fifty-two eligible studies were identified and summarized. These studies were conducted in 14 different countries, with the largest number of studies being completed in the United States (34.6%). A therapeutic response, wanting control, a strong belief in CAM, CAM as a last resort, and finding hope were the most commonly cited reasons for using CAM. Age, socioeconomic status, and gender were the dominant characteristics associated with CAM use.
CONCLUSIONS
Reasons for and characteristics associated with CAM use among cancer patients have been studied extensively. Future CAM research among cancer patients should focus on identifying decision-making processes and building theoretical decision-making models. These can be used in the development of decisional aids for patients when confronted with the choice to use CAM as part of their cancer treatment.
Publication
Journal: Molecular Neurobiology
June/1/2009
Abstract
Amphetamine (AMPH) and its derivatives are regularly used in the treatment of a wide array of disorders such as attention-deficit hyperactivity disorder (ADHD), obesity, traumatic brain injury, and narcolepsy (Prog Neurobiol 75:406-433, 2005; J Am Med Assoc 105:2051-2054, 1935; J Am Acad Child Adolesc Psychiatry 41:514-521, 2002; Neuron 43:261-269, 2004; Annu Rev Pharmacol Toxicol 47:681-698, 2007; Drugs Aging 21:67-79, 2004). Despite the important medicinal role for AMPH, it is more widely known for its psychostimulant and addictive properties as a drug of abuse. The primary molecular targets of AMPH are both the vesicular monoamine transporters (VMATs) and plasma membrane monoamine-dopamine (DA), norepinephrine (NE), and serotonin (5-HT)-transporters. The rewarding and addicting properties of AMPH rely on its ability to act as a substrate for these transporters and ultimately increase extracellular levels of monoamines. AMPH achieves this elevation in extracellular levels of neurotransmitter by inducing synaptic vesicle depletion, which increases intracellular monoamine levels, and also by promoting reverse transport (efflux) through plasma membrane monoamine transporters (J Biol Chem 237:2311-2317, 1962; Med Exp Int J Exp Med 6:47-53, 1962; Neuron 19:1271-1283, 1997; J Physiol 144:314-336, 1958; J Neurosci 18:1979-1986, 1998; Science 237:1219-1223, 1987; J Neurosc 15:4102-4108, 1995). This review will focus on two important aspects of AMPH-induced regulation of the plasma membrane monoamine transporters-transporter mediated monoamine efflux and transporter trafficking.
Publication
Journal: Medical Engineering and Physics
February/4/2009
Abstract
This paper reviews various bioimpedance methods permitting to measure non-invasively, extracellular, intracellular and total body water (TBW) and compares BIA methods based on empirical equations of the wrist-ankle resistance or impedance at 50 kHz, height and weight with BIS methods which rely on an electrical model of tissues and resistances measured at zero and infinite frequencies. In order to compare these methods, impedance measurements were made with a multifrequency Xitron 4200 impedance meter on 57 healthy subjects which had undergone simultaneously a Dual X-ray absorptiometry examination (DXA), in order to estimate their TBW from their fat-free-mass. Extracellular (ECW) and TBW volumes were calculated for these subjects using the original BIS method and modifications of Matthie[Matthie JR. Second generation mixture theory equation for estimating intracellular water using bioimpedance spectroscopy. J Appl Physiol 2005;99:780-1], Jaffrin et al. [Jaffrin MY, Fenech M, Moreno MV, Kieffer R. Total body water measurement by a modification of the bioimpédance spectroscopy method. Med Bio Eng Comput 2006;44:873-82], Moissl et al. [Moissl UM, Wabel P, Chamney PW, Bosaeus I, Levin NW, et al. Body fluid volume determination via body composition spectroscopy in health and disease. Physiol Meas 2006;27:921-33] and their TBW resistivities were compared and discussed. ECW volumes were calculated by BIA methods of Sergi et al. [Sergi G, Bussolotto M, Perini P, Calliari I, et al. Accuracy of bioelectrical bioimpedance analysis for the assessment of extracellular space in healthy subjects and in fluid retention states. Ann Nutr Metab 1994;38(3):158-65] and Hannan et al. [Hannan WJ, Cowen SJ, Fearon KC, Plester CE, Falconer JS, Richardson RA. Evaluation of multi-frequency bio-impedance analysis for the assessment of extracellular and total body water in surgical patients. Clin Sci 1994;86:479-85] and TBW volumes by BIA methods of Kushner and Schoeller [Kushner RF, Schoeller DA. Estimation of total body water by bioelectrical impedance analysis. Am J Clin Nutr 1986;44(3):417-24], Lukaski et al. [Lukaski HC, Bolonchuk WW. Estimation of body fluid volumes using tetrapolar bioelectrical impedance measurements. Aviat Space Environ Med 1988;59:1163-9], Hannan et al. [Hannan WJ, Cowen SJ, Fearon KC, Plester CE, Falconer JS, Richardson RA. Evaluation of multi-frequency bio-impedance analysis for the assessment of extracellular and total body water in surgical patients. Clinical Science 1994;86:479-85], Deurenberg et al. [Deurenberg P, van der Koy K, Leenen R, Westrate JA, Seidell JC. Sex and age specific prediction formulas for estimating body composition from bioelectric impedance: a cross validation study. Int J Obesity 1991;15:17-25] These volumes were compared against those given by BIS method and, in the case of TBW, with those by DXA. For ECW, a good agreement was found between various BIS methods and that of Sergi while Hannan's values were higher. Both Matthie's and Moissl's methods gave mean TBW resistivities and volumes lower than those of Jaffrin's and DXA methods. Kushner et al. method gave values of TBW not significantly different from those of Jaffrin et al. and DXA, as Hannan's method in men, but Lukaski and Deurenberg methods led to an underestimation.
Publication
Journal: Human Brain Mapping
October/25/1998
Abstract
Statistical mapping within a binary hypothesis testing framework is the most widely used analytical method in functional MRI of the brain. A common assumption in this kind of analysis is that the fMRI time series are independent and identically distributed in time, yet we know that fMRI data can have significant temporal correlation due to low-frequency physiological fluctuation (Weisskoff et al. [1993]; Proc Soc Magn Reson Med 9:7; Biswal et al. [1995]: Mag Reson Med 34:537-541). Furthermore, since the signal-to-noise ratio will vary with imaging rate, we should expect that the degree of correlation will vary with imaging rate. In this paper, we investigate the effect of temporal correlation and experimental paradigm on false-positive rates (type I error rates), using data synthesized through a simple autoregressive plus white-noise model whose parameters were estimated from real data over a range of imaging rates. We demonstrate that actual false-positive rates can be biased far above or below the assumed significance level alpha when temporal autocorrelation is ignored in a way that depends on both the degree of correlation as well as the paradigm frequency. Furthermore, we present a simple method, based on the noise model described above, for correcting such distortions, and relate this method to the extended general linear model of Worsley and Friston ([1995]: Neuroimage 2:173-181).
Publication
Journal: Radiotherapy and Oncology
May/8/2013
Abstract
OBJECTIVE
Hypoxia is a cause of resistance to radiotherapy, especially in patients with head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to evaluate (18)F-fluoroazomycin arabinoside (FAZA) positron emission tomography (PET)/computed tomography (CT) hypoxia imaging as a prognostic factor in HNSCC patients receiving radiotherapy.
METHODS
Forty patients with HNSCC treated with radiotherapy (66-76 Gy) were included. Static FAZA PET/CT imaging 2h post injection was conducted prior to irradiation. The hypoxic volume (HV) was delineated using a tumor-to-muscle value ≥ 1.4. In 13 patients, a repetitive FAZA PET/CT scan was conducted during the radiotherapy treatment.
RESULTS
A hypoxic volume could be identified in 25 (63%) of the 40 tumors. FAZA PET HV varied considerably with a range from 0.0 to 30.9 (median: 0.3) cm(3). The T(max)/M(med) ranged from 1.1 to 2.9 (median: 1.5). The distribution of hypoxia among the Human Papillomavirus (HPV) positive (12/16) and negative (13/24) tumors was not significant different. In the FAZA PET/CT scans performed during radiotherapy, hypoxia could be detected in six of the 13 patients. For these six patients the location of HV remained stable in location during radiotherapy treatment, though the size of the HV decreased. In 30 patients a positive correlation was detected between maximum FAZA uptake in the primary tumor and the lymph node. During a median follow up of 19 months a significant difference in disease free survival rate with 93% for patients with non hypoxic tumors and 60% for patients with hypoxic tumors could be detected.
CONCLUSIONS
This study emphasizes the role of FAZA PET/CT imaging as a suitable assay with prognostic potential for detection of hypoxia in HNSCC.
Publication
Journal: Pharmacology Biochemistry and Behavior
February/4/2002
Abstract
In the present studies, base line and drug-induced performance of two mouse strains (C57Bl/6 and NIH-Swiss) was evaluated in the forced swim test (FST) and tail suspension test (TST). Intra- and interstrain comparisons indicate that the biological substrates mediating performance in these behavioral procedures are not identical. For example, in NIH-Swiss mice, a sevenfold difference in base line immobility was observed between the FST and TST. By contrast, the base line immobility in C57Bl/6 mice was similar in both procedures. Further, in C57Bl/6 mice, imipramine produced a "U-shaped" dose-response curve in the FST, whilst no evidence of a biphasic response was present in the TST at doses up to 45 mg/kg. In the FST, the AMPA receptor potentiator LY451646 produced a similar dose-response relationship in C57Bl/6 and NIH-Swiss mice, but the minimum effect dose (MED) was fivefold higher in NIH-Swiss mice. This potency difference appears due to both pharmacokinetic and pharmacodynamic factors. These intra- and interstrain differences in performance indicate that despite a face value similarity, the neurochemical pathways involved in mediating performance in these two widely used tests are not identical.
Publication
Journal: Cancer Letters
June/3/2007
Abstract
Mitochondria are the major source of Reactive Oxygen Species (ROS) and mtDNA G10398A (Ala->>Thr) polymorphism, proposed to be involved in increased ROS production, has been shown in association with invasive breast cancer in African-American (AA) women [J.A. Canter, A.R. Kallianpur, F.F. Parl, R.C. Millikan, Mitochondrial DNA G10398A polymorphism and invasive breast cancer in African-American women, Cancer Res. 65 (2005) 8028-8033] and prostate cancer in AA men [M.P. Mims, T.G. Hayes, S. Zheng, S.M. Leal, A. Frolov, M.M. Ittmann, et al., Mitochondrial DNA G10398A polymorphism and invasive breast cancer in African-American women, Cancer Res. 66 (2006) 1880; author reply 1880-1881]. The role of mitochondria, however, in cancer development has been in question recently [A. Salas, Y.G. Yao, V. Macaulay, A. Vega, A. Carracedo, H.J. Bandelt, A critical reassessment of the role of mitochondria in tumorigenesis, PLoS Med. 2 (2005) e296], which has made it pertinent to analyze the data and test the hypotheses by conducting fresh case-control studies. This study, therefore, makes an attempt to validate the exclusive presence of mtG10398A (Ala->>Thr) polymorphism in a haplotype constituting mtDNA haplogroup N and its sublineages, imparting this group a higher risk for breast cancer, based on the re-analyses of approximately 1000 complete human mtDNA sequences worldwide and collated information on 2334 individuals belonging to 18 regions in India. The conclusion drawn of mt10398A allele providing a risk towards cancer is confirmed in a case-control comparison study of 124 sporadic breast cancer patients and 273 controls; and 55 squamous cell carcinoma of esophagus, ESCC, and 163 controls, matched for age, ethnicity and sex from north India. It is further apparent from the study that such a mtDNA polymorphism background provides a higher risk for the cancers of the tissues which could be affected by environmental insults directly as in the ESCC, observed with a high acquired (somatic) rate of mutation in p53 when compared to the breast cancer, suggesting that the mtDNA variants that arose as energetic adaptations, influence our health differentially under different environment conditions and a given genetic background of the mt genome.
Publication
Journal: Clinical Infectious Diseases
February/21/1994
Abstract
Dr. William G. Powderly provides a comprehensive review of the state of our knowledge regarding cryptococcal infection in persons with infection due to human immunodeficiency virus type 1. The introduction of fluconazole and itraconazole increased insight into prognostic factors affecting these patients. The need to suppress this fungal infection in individuals with impaired immunity has greatly altered the management of cryptococcal meningitis; therapy for this condition was established by the landmark study conducted by the Mycosis Study Group in 1979 (Bennett JE, Dismukes WE, Duma RJ, et al. A comparison of amphotericin B alone and combined with flucytosine in treatment of cryptococcal meningitis. N Engl J Med 1979;301:126-31). In this AIDS commentary Dr. Powderly clearly outlines the progress made through clinical investigations and the problems that remain to be resolved.
Publication
Journal: American journal of medical genetics
August/31/1998
Abstract
Genetic syndromes associated with deletions at chromosome 22q11 generally have been diagnosed during childhood based on a constellation of physical features. To investigate a reported association of velocardiofacial syndrome with psychotic disorders in adults, we assessed subjects with DSM-IV schizophrenia or schizoaffective disorder who were referred with two or more syndromal features (palatal, cardiac, facial, or other congenital anomalies, and/or learning difficulties). We report on 10 subjects (5 men and 5 women), mean age 27.2 (SD 6.0) years, who were found to have a 22q11 deletion at locus D22S75 using fluorescence in-situ hybridization (FISH). The mean age at onset of psychosis was 19.6 (SD 4.6) years. Symptoms and course of the psychotic illnesses were unremarkable, but additional signs such as temper outbursts were common. These adult subjects had significantly fewer major palatal (P = .0001) and conotruncal cardiac (P = .05) anomalies but the same high rate of learning difficulties as a sample with deletion 22q11 ascertained through a pediatric clinic [Lindsay et al. (1995): Am J Med Genet 57:514-522]. Minor congenital features and rate of transmitted cases were similar to those previously reported. These results replicate the association of a 22q11 deletion syndrome with schizophrenia and confirm the importance of ascertainment in influencing the phenotype found. The findings support a developmental gene in the 22q11 deletion region causing a complex phenotype which may include significant behavioral components that emerge over time. We support using the term "22q11 deletion syndrome (22DS)," which would encompass physical and psychiatric features, and could also be applied to describe a genetic subtype of schizophrenia.
Publication
Journal: Magnetic Resonance in Medicine
January/3/2000
Abstract
A magnetization-transfer (MT) CPMG hybrid experiment was performed to analyze T(2) relaxation and MT characteristics in bovine optic nerve. Two exchanging liquid pools with their own, independent MT characteristics were necessary to model both the T(2) relaxation and the MT data. The model agrees well with the experimental data and yields physically realistic parameters. The MT effect for myelin water is approximately nine time larger than that for intra/intercellular water, indicating that the MT characteristics observed for white matter are mainly related to myelin. The model can be used to probe parameters that would be difficult to achieve experimentally. The exchange process between the two tissue compartments does not drastically affect the amplitudes and relaxation rates of the T(2) components, but is fast enough to significantly influence their MT characteristics. Although, both the MT and T(2) experiments described in this paper are too time consuming to be applied in routine clinical work, presented results can be useful in interpreting clinical pulse sequences that are sensitive to myelin. Magn Reson Med 42:1128-1136, 1999.
Publication
Journal: Microbial Ecology
November/25/2014
Abstract
Pseudomonas aeruginosa is a ubiquitous organism that is the focus of intense research because of its prominent role in disease. Due to its relatively large genome and flexible metabolic capabilities, this organism exploits numerous environmental niches. It is an opportunistic pathogen that sets upon the human host when the normal immune defenses are disabled. Its deadliness is most apparent in cystic fibrosis patients, but it also is a major problem in burn wounds, chronic wounds, chronic obstructive pulmonary disorder, surface growth on implanted biomaterials, and within hospital surface and water supplies, where it poses a host of threats to vulnerable patients (Peleg and Hooper, N Engl J Med 362:1804-1813, 2010; Breathnach et al., J Hosp Infect 82:19-24, 2012). Once established in the patient, P. aeruginosa can be especially difficult to treat. The genome encodes a host of resistance genes, including multidrug efflux pumps (Poole, J Mol Microbiol Biotechnol 3:255-264, 2001) and enzymes conferring resistance to beta-lactam and aminoglycoside antibotics (Vahdani et al., Annal Burns Fire Disast 25:78-81, 2012), making therapy against this gram-negative pathogen particularly challenging due to the lack of novel antimicrobial therapeutics (Lewis, Nature 485: 439-440, 2012). This challenge is compounded by the ability of P. aeruginosa to grow in a biofilm, which may enhance its ability to cause infections by protecting bacteria from host defenses and chemotherapy. Here, we review recent studies of P. aeruginosa biofilms with a focus on how this unique mode of growth contributes to its ability to cause recalcitrant infections.
Publication
Journal: Journal of Urology
November/23/1999
Abstract
OBJECTIVE
We review the literature and characterize the clinical findings of von Recklinghausen's associated pheochromocytoma.
METHODS
A Grateful Med search for the years 1966 to 1999 was performed on the subjects, "von Recklinghausen" and "neurofibromatosis." Articles from the Grateful Med search were then reviewed to identify older publications. Of 325 articles 118 are included in this review.
RESULTS
Pheochromocytomas have been clinically identified in 0.1 to 5.7% of patients with von Recklinghausen's disease. Mean patient age was 42 years (range 1.5 to 74) in 87 women and 61 men at presentation with pheochromocytoma. Of the 148 patients 84% had solitary adrenal tumors, 9.6% bilateral adrenal disease and 6.1% ectopic pheochromocytomas. Symptoms related to pheochromocytoma or hypertension were noted in 78% of the patients. Tumors secreted epinephrine and norepinephrine, and 87% demonstrated metaiodobenzylguanidine uptake. Of the 148 patients 6% died during pregnancy or a medical procedure, or due to hypertensive crisis without apparent provocation, 8.8% had gastrointestinal carcinoid tumors and 11.5% had metastases or local invasion from pheochromocytoma.
CONCLUSIONS
Pheochromocytomas occur in a small but defined number of patients with von Recklinghausen's disease, and can be associated with significant morbidity and mortality if not detected. Screening of patients with von Recklinghausen's disease and hypertension or before provocative procedures or pregnancy seems to be indicated.
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