High flow nasal insufflations (NI) can improve gas exchange and alleviate dyspnea in patients with acute respiratory failure. In the present study we investigated the effects of high flow nasal insufflations in COPD patients with chronic hypercapnic respiratory failure (HRF). Seventeen patients with severe COPD and HRF were recruited. We delivered a mixture of 20 L/min room air and 2 L/min O(2) through a nasal cannula either into both nostrils (NI) or into one nostril (Partial NI). Respiratory pattern and PaCO(2) responses under NI were compared with low flow oxygen of 2 L/min. High flow nasal insufflations led to a systematic reduction in respiratory rate from 19.8 ± 4.2 at baseline to 18.0 ± 4.7 during NI (p < 0.008) and 18.1 ± 5.2 breaths/min during Partial NI (P < 0.03). The mean group inspiratory duty cycle (T(I)/T(T)) and mean group PaCO(2) remained constant between all experimental conditions. Individual responses to NI were heterogeneous: six patients demonstrated marked reductions in respiratory rate (>20% fall from baseline), another group (n = 6) demonstrated no change in respiratory rate but marked reductions in arterial carbon dioxide of more than 8 mmHg. In conclusion, high flow (20 L/min) nasal insufflations of warm and humidified air during wakefulness for 45 min reduced respiratory rate without deterioration of hypercapnia. Our data indicate that high flow NI improved efficiency of breathing and may be used as an adjunct to low flow oxygen for preventing hypercapnic respiratory failure in severely ill COPD patients.

BACKGROUND

There is growing evidence for the idea of fMRI activation in white matter. In the current study, we compared hemodynamic response functions (HRF) in white matter and gray matter using 4 T fMRI. White matter fMRI activation was elicited in the isthmus of the corpus callosum at both the group and individual levels (using an established interhemispheric transfer task). Callosal HRFs were compared to HRFs from cingulate and parietal activation.

RESULTS

Examination of the raw HRF revealed similar overall response characteristics. Finite impulse response modeling confirmed that the WM HRF characteristics were comparable to those of the GM HRF, but had significantly decreased peak response amplitudes.

CONCLUSIONS

Overall, the results matched a priori expectations of smaller HRF responses in white matter due to the relative drop in cerebral blood flow (CBF) and cerebral blood volume (CBV). Importantly, the findings demonstrate that despite lower CBF and CBV, white matter fMRI activation remained within detectable ranges at 4 T.

Within-subject analysis in fMRI essentially addresses two problems, the detection of brain regions eliciting evoked activity and the estimation of the underlying dynamics. In Makni et aL, 2005 and Makni et aL, 2008, a detection-estimation framework has been proposed to tackle these problems jointly, since they are connected to one another. In the Bayesian formalism, detection is achieved by modeling activating and nonactivating voxels through independent mixture models (IMM) within each region while hemodynamic response estimation is performed at a regional scale in a nonparametric way. Instead of IMMs, in this paper we take advantage of spatial mixture models (SMM) for their nonlinear spatial regularizing properties. The proposed method is unsupervised and spatially adaptive in the sense that the amount of spatial correlation is automatically tuned from the data and this setting automatically varies across brain regions. In addition, the level of regularization is specific to each experimental condition since both the signal-to-noise ratio and the activation pattern may vary across stimulus types in a given brain region. These aspects require the precise estimation of multiple partition functions of underlying Ising fields. This is addressed efficiently using first path sampling for a small subset of fields and then using a recently developed fast extrapolation technique for the large remaining set. Simulation results emphasize that detection relying on supervised SMM outperforms its IMM counterpart and that unsupervised spatial mixture models achieve similar results without any hand-tuning of the correlation parameter. On real datasets, the gain is illustrated in a localizer fMRI experiment: brain activations appear more spatially resolved using SMM in comparison with classical general linear model (GLM)-based approaches, while estimating a specific parcel-based HRF shape. Our approach therefore validates the treatment of unsmoothed fMRI data without fixed GLM definition at the subject level and makes also the classical strategy of spatial Gaussian filtering deprecated.

This cross-sectional study examined associations among motor skill competence (MSC) and health-related fitness (HRF) in youth. A convenient sample of 253 boys and 203 girls (aged 4-13 years) participated in the study. Associations among measures of MSC (throwing and kicking speed and standing long jump distance) and a composite measure of HRF (push-ups, curl-ups, grip strength and PACER test) across five age groups (4-5, 6-7, 8-9, 10-11 and 12-13 yrs.) were assessed using hierarchical regression modeling. When including all children, throwing and jumping were significantly associated with the composite HRF factor for both boys and girls (throw, t = 5.33; jump, t = 4.49) beyond the significant age effect (t = 4.98) with kicking approaching significance (t = 1.73, p = .08). Associations between throwing and kicking speed and HRF appeared to increase from early to middle to late childhood age ranges. Associations between jumping and HRF were variable across age groups. These results support the notion that the relationship between MSC and HRF performance are dynamic and may change across childhood. These data suggest that the development of object control skills in childhood may be important for the development and maintenance of HRF across childhood and into adolescence.

It has been known for decades that mutagenicity plays an important role in the activity of most carcinogens. This mutagenicity can result from direct damage to DNA through a chemical being DNA reactive or from indirect effects, such as through the production of oxygen radicals that then react with DNA. This article presents a set of key events whereby DNA reactivity initiates the process of carcinogenicity that leads to the subsequent mutation induction and enhanced cell proliferation that ultimately results in tumor development. This set of key events for DNA-reactive chemicals was applied to two case studies (aflatoxin B1 and dichloromethane) with the aim of assessing the utility of the Human Relevance Framework (HRF) for this class of chemicals. The conclusions were that the HRF was a viable approach for the use of mechanistic data for DNA-reactive chemicals obtained from both laboratory animals and human cells in vivo and in vitro for predicting human carcinogenicity. In the case of aflatoxin B1, the HRF could be used to predict that carcinogenicity in humans was a likely outcome. In contrast, the HRF predicted that the human carcinogenic potential of dichloromethane was at best less likely than in rodents; this conclusion was supported by the available epidemiological data.

OBJECTIVE

To determine the longitudinal association of components of health-related functioning (HRF) with incident impaired glucose metabolism and type 2 diabetes.

METHODS

The Australian Diabetes Obesity and Lifestyle (AusDiab) study is a national, longitudinal study of adults aged>> or =25 years from 42 randomly selected areas of Australia. Diabetes status was defined using the World Health Organization criteria, and HRF was assessed using the SF-36 questionnaire in 1999-2000 and 2004-2005.

RESULTS

Incident impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and newly diagnosed type 2 diabetes were associated with increased bodily pain at baseline compared with those with normal glucose tolerance (NGT) (IFG P = 0.005, IGT P < 0.004, and newly diagnosed type 2 diabetes P = 0.005), after adjustment. In addition, those with incident IGT and newly diagnosed type 2 diabetes had significantly reduced physical functioning, general health, mental health, and vitality at baseline compared with those with NGT. After we controlled for factors associated with incident diabetes, those in the lowest quartile of the physical component summary scale at baseline had at least a 50% higher risk of progression to impaired glucose metabolism and diabetes 5 years later.

CONCLUSIONS

These findings show that incident IFG, IGT, and newly diagnosed type 2 diabetes are associated with reduced HRF independent of cardiovascular disease and that this is evident before the onset of these conditions. If future health promotion campaigns are to effectively target those at high risk of developing diabetes, an understanding of the process of declining health before onset of the disease is essential.

Treatment of murine resident peritoneal macrophages with macrophage-CSF (M-CSF) up-regulated the synthesis of a discrete set of proteins, including a 26-kDa protein (p26). The sequence of 20 NH2-terminal amino acids of the purified p26 was identical with the mouse homolog of a human IgE-dependent histamine-releasing factor (HRF). Among macrophage activators tested (M-CSF, granulocyte-macrophage-CSF, IL-3, TNF-alpha, IFN-gamma, and LPS), only M-CSF could up-regulate the p26 HRF synthesis by cultured macrophages. M-CSF not only increased the levels of p26 HRF mRNA and protein, but also stimulated the secretion of an N-glycosylated p26 HRF with a m.w. of 30 kDa. Repeated injections of M-CSF into mouse peritoneal cavity for 4 days elicited macrophages expressing abundant p26 HRF. A single i.p. injection of M-CSF failed to increase the p26 HRF level in peritoneal macrophages of thioglycollate-, LPS-, or adjuvant-treated mice, while M-CSF challenge to OVA-immunized mice caused macrophage infiltration and overproduction of p26 HRF, similarly as did OVA challenge. The Ag-specific priming for enhanced synthesis and secretion of p26 HRF by M-CSF was also demonstrated in cultured macrophages prepared from OVA-immunized mice. An i.p. injection of M-CSF or recombinant p26 HRF triggered eosinophil recruitment, even in the absence of the Ag, in the sensitized mice, but not in normal mice. Furthermore, recombinant p26 HRF could induce eosinophilia without marked macrophage and lymphocyte infiltrations. Our results suggest that p26 HRF secreted by M-CSF-stimulated macrophages may be an important mediator for the late phase allergic inflammation.

OBJECTIVE

Our goal was to determine whether visual system responses to sildenafil accompany shifts in ocular perfusion. The human choroid, which supports the metabolic function of the outer retina, is an erectile tissue, analogous in many respects to the corpus cavenosum.

METHODS

Right eyes of 12 normal adults were evaluated before and 2 h after 50 mg oral dose of sildenafil. Pulsatile ocular blood flow (POBF), intraocular pressure (IOP), Heidelberg retinal flowmetry (HRT), 4.26 cpd, 7.5 Hz temporally-modulated contrast sensitivity (CS), full-threshold C-20 frequency doubling technology (FDT) perimetry, and blood pressure (BP) were measured.

RESULTS

POBF (+29.4%; p>> 0.016) and CS (+33.6%; p>> 0.014%) increased within 110 (+/-7.7) minutes after sildenafil administration. No subject demonstrated decreases in either variable. HRF flow values increase among 7 of the 9 eyes producing stable scans (+8.2%; p>> 0.1). FDT values did not change significantly, nor did systemic pulse amplitude or mean IOP.

CONCLUSIONS

Since IOP and systemic pulse amplitude both remained stable after sildenafil administration, while POBF values increased to a level nearly one third greater than baseline. It appears sildenafil can induce intrinsic change in the choroidal vasculature, with an apparently positive impact on pericentral contrast sensitivity. This effect may be of clinical utility.

The identity and activity of several anti-HIV soluble factor(s) secreted by CD8 and CD4 T lymphocytes have been determined; however, some of them still await definition. We have established an HIV-1-resistant, transformed CD4 T cell line that secretes HIV-1 resistance protein(s). Our studies indicate that this protein(s), called HIV-1 resistance factor (HRF), inhibits transcription of the virus by interfering with the activity of NF-kappaB. In the present report we identified the site at which HRF exerts this inhibition by evaluating a set of discrete events in NF-kappaB action. We tested the kappaB oligonucleotide binding activity in nuclei of resistant cells, nuclear translocation and binding to the HIV-1 long terminal repeat of p65 and p50 proteins from susceptible cells after exposure to HRF, and the binding of recombinant p50 to the kappaB oligonucleotide in vitro as affected by prior or simultaneous exposure to HRF. The results of this experimental schema indicate that HRF interacts with p50 after it enters the nucleus, but before its binding to DNA and that this interaction impedes the formation of an NF-kappaB-DNA complex required for the promotion of transcription. These findings suggest that HRF mediates a novel innate immune response to virus infection.

Histamine-releasing factor (HRF) stimulates secretion of histamine that is widely distributed in brain and released as neurotransmitter. Several studies suggested that histaminergic deficits could contribute to the cognitive decline in Alzheimer's disease (AD). Based upon deranged histamine metabolism in brain of patients with AD and Down Syndrome (DS), we aimed to study HRF in brain of AD and DS. We used two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization mass spectroscopy and specific software to quantify HRF. HRF was significantly reduced in temporal cortex, thalamus and caudate nucleus of DS and in temporal cortex of AD as compared to controls. This is the first report to show decreased HRF brain levels in DS and AD suggesting the explanation for the decreased cognitive function in neurodegenerative/dementing disorders.

OBJECTIVE

To assess retinal blood flow characteristics in subjects with normal tension glaucoma (NTG), primary open angle glaucoma (POAG), and a group of controls using the Heidelberg retina flowmeter (HRF). The vascular parameters were correlated against structural damage of the optic nerve head, assessed using the Heidelberg retina tomograph (HRT).

METHODS

HRF images were obtained in 76 subjects with NTG, 58 with POAG, and 38 controls. Optic nerve head images, acquired using the HRT, were analysed with Moorfields Regression Analysis software. The HRF variables, measured adjacent to a rim segment identified as "abnormal," were compared with the vascular parameters of the "normal" rim segments. The HRF parameters of the segments identified as normal in glaucoma subjects were compared with matched control segments.

RESULTS

The glaucoma subjects had significantly lower retinal haemodynamics than the control subjects. There were no significant differences in the HRF parameters between the NTG and POAG subjects. The discs that had been identified as having abnormal segments had lower HRF values than those with a corresponding normal segment. The glaucoma subjects with normal rim segments had statistically significant lower velocity, flow, and volume measurements than the controls for each location sampled.

CONCLUSIONS

This study shows a relation between structural damage of the optic nerve head and the level of retinal blood flow. The changes in the circulation could indicate that it may be an early marker of the pathological process.

Vinclozolin is a fungicide that has been shown to cause Leydig cell tumors and atrophy of the accessory sex glands in adult rodents. In addition, exposure of rats during pregnancy causes a pattern of malformations in the male urogenital tract. A wealth of standard toxicological studies and targeted research efforts is available related to this adverse effect, and these were used to evaluate the Human Relevance Framework (HRF) for noncancer health effects. Vinclozolin and two of its metabolites, designated M1 and M2, have been shown to bind and inhibit the function of the rat and human androgen receptor. Other means of interfering with androgen receptor function (e.g., by exposure to the pharmaceutical agent flutamide) lead to similar adverse health outcomes. There is direct in vivo evidence in the rat prostate that androgen-dependent gene expression changes occur after exposure to vinclozolin. There are no proposed alternatives to the androgen receptor-mediated mode of action. Based on what is known about kinetic and dynamic factors, confidence is high that the animal mode of action (MOA) for vinclozolin-induced malformation of the male reproductive tract is highly plausible in humans.

A new approach for analysis of event-related fMRI (BOLD) signals is proposed. The technique is based on measures from information theory and is used both for spatial localization of task-related activity, as well as for extracting temporal information regarding the task-dependent propagation of activation across different brain regions. This approach enables whole brain visualization of voxels (areas) most involved in coding of a specific task condition, the time at which they are most informative about the condition, as well as their average amplitude at that preferred time. The approach does not require prior assumptions about the shape of the hemodynamic response function (HRF) nor about linear relations between BOLD response and presented stimuli (or task conditions). We show that relative delays between different brain regions can also be computed without prior knowledge of the experimental design, suggesting a general method that could be applied for analysis of differential time delays that occur during natural, uncontrolled conditions. Here we analyze BOLD signals recorded during performance of a motor learning task. We show that, during motor learning, the BOLD response of unimodal motor cortical areas precedes the response in higher-order multimodal association areas, including posterior parietal cortex. Brain areas found to be associated with reduced activity during motor learning, predominantly in prefrontal brain regions, are informative about the task typically at significantly later times.

Combining electroencephalogram (EEG) and functional MRI (fMRI) allows localization of brain regions activated as a result of epileptic spikes. The statistical analysis of fMRI data usually includes a standard model of the hemodynamic response function (HRF) but it is not known how well this fits the actual HRF of epileptic spikes. The objective of this exploratory study was to compare the activated areas and t-statistical scores obtained with a standard HRF to those obtained with a patient-specific HRF. Eight patients with focal epilepsy were studied. We obtained an estimate of the patient-specific HRFs for each patient at the local maximum of activation in the standard HRF analysis. The activated areas obtained with the patient-specific HRFs were larger or similar to the originally activated areas. Additional activated areas were seen in five patients, and most were compatible with the EEG and anatomical MRI localization of epileptogenic and lesional regions. Using patient-specific HRFs brings increased sensitivity to the analysis of epileptic spikes by EEG-fMRI.

Envenoming with brown spiders (Loxosceles genus) is common throughout the world. Cutaneous symptoms following spider bite accidents include dermonecrosis, erythema, itching and pain. In some cases, accidents can cause hypersensibility or even allergic reactions. These responses could be associated with histaminergic events, such as an increase in vascular permeability and vasodilatation. A protein that may be related to the effects of spider venom was identified from a previously obtained cDNA library of the L. intermedia venom gland. The amino acid sequence of this protein is homologous to proteins from the TCTP (translationally-controlled tumor protein) family, which are extracellular histamine-releasing factors (HRF) that are associated with the allergic reactions to parasites. Herein, we described the cloning, heterologous expression, purification and functional characterization of a novel member of the TCTP family from the Loxosceles intermedia venom gland. This recombinant protein, named LiRecTCTP, causes edema, enhances vascular permeability and is likely related to the inflammatory activity of the venom. Moreover, LiRecTCTP presents an immunological relationship with mammalian TCTPs.

Functional ultrasound imaging is a method recently developed to assess brain activity via hemodynamics in rodents. Doppler ultrasound signals allow the measurement of cerebral blood volume (CBV) and red blood cells' (RBCs') velocity in small vessels. However, this technique originally requires performing a large craniotomy that limits its use to acute experiments only. Moreover, a detailed description of the hemodynamic changes that underlie functional ultrasound imaging has not been described but is essential for a better interpretation of neuroimaging data. To overcome the limitation of the craniotomy, we developed a dedicated thinned skull surgery for chronic imaging. This procedure did not induce brain inflammation nor neuronal death as confirmed by immunostaining. We successfully acquired both high-resolution images of the microvasculature and functional movies of the brain hemodynamics on the same animal at 0, 2, and 7 days without loss of quality. Then, we investigated the spatiotemporal evolution of the CBV hemodynamic response function (HRF) in response to sensory-evoked electrical stimulus (1 mA) ranging from 1 (200 μs) to 25 pulses (5s). Our results indicate that CBV HRF parameters such as the peak amplitude, the time to peak, the full width at half-maximum and the spatial extent of the activated area increase with stimulus duration. Functional ultrasound imaging was sensitive enough to detect hemodynamic responses evoked by only a single pulse stimulus. We also observed that the RBC velocity during activation could be separated in two distinct speed ranges with the fastest velocities located in the upper part of the cortex and slower velocities in deeper layers. For the first time, functional ultrasound imaging demonstrates its potential to image brain activity chronically in small animals and offers new insights into the spatiotemporal evolution of cerebral hemodynamics.

BACKGROUND

The performance of complex tasks on the International Space Station (ISS) requires significant preflight crew training commitments and frequent skill and knowledge refreshment. This report documents a recently developed "just-in-time" training methodology, which integrates preflight hardware familiarization and procedure training with an on-orbit CD-ROM-based skill enhancement. This "just-in-time" concept was used to support real-time remote expert guidance to complete ultrasound examinations using the ISS Human Research Facility (HRF).

METHODS

An American and Russian ISS crewmember received 2 h of "hands on" ultrasound training 8 mo prior to the on-orbit ultrasound exam. A CD-ROM-based Onboard Proficiency Enhancement (OPE) interactive multimedia program consisting of memory enhancing tutorials, and skill testing exercises, was completed by the crewmember 6 d prior to the on-orbit ultrasound exam. The crewmember was then remotely guided through a thoracic, vascular, and echocardiographic examination by ultrasound imaging experts.

RESULTS

Results of the CD-ROM-based OPE session were used to modify the instructions during a complete 35-min real-time thoracic, cardiac, and carotid/jugular ultrasound study. Following commands from the ground-based expert, the crewmember acquired all target views and images without difficulty. The anatomical content and fidelity of ultrasound video were adequate for clinical decision making.

CONCLUSIONS

Complex ultrasound experiments with expert guidance were performed with high accuracy following limited preflight training and multimedia based in-flight review, despite a 2-s communication latency. In-flight application of multimedia proficiency enhancement software, coupled with real-time remote expert guidance, facilitates the successful performance of ultrasound examinations on orbit and may have additional terrestrial and space applications.

In our previous studies we reported that lymphocytes from patients with asthma spontaneously produce histamine-releasing factor (HRF) in vitro. In an effort to examine whether spontaneous HRF production (SpHRF) by lymphocytes from patients with asthma is related to the state of bronchial hyperreactivity (BHR), 20 patients with mild to severe asthma were studied. Peripheral blood lymphocytes were cultured alone in a serum-free medium for 24 hours, and culture supernatant was assayed for HRF activity in two separate histamine-release tests with autologous basophils and normal basophils from known healthy donors. BHR was measured as bronchial reactivity to inhaled histamine and was expressed as a provocation concentration of histamine required to induce a 20% fall in FEV1 (PC20). The result of this study demonstrated that lymphocyte supernatant from all patients with asthma released significant amount of histamine from both autologous and normal basophils. Very high histamine release was usually induced by lymphocyte supernatant from severely ill patients who had PC20 less than 2 mg/ml. Statistical analysis demonstrated that the magnitude of the SpHRF significantly correlated (r = -0.86; p less than 0.001) with PC20. Since mast cell- and basophil-derived mediators have been implicated in the pathogenesis of BHR, high correlation between PC20 and SpHRF by lymphocytes suggests that the latter may contribute to the development of BHR. Further studies are required to disclose the exact relationship between SpHRF and BHR.

No episodes of clinically significant in vivo haemolysis have been reported in individuals with a novel form of decay accelerating factor (DAF) deficiency (Inab phenotype), nor do functional in vitro assays for complement-mediated haemolysis show the extreme sensitivity to lysis characteristic of paroxysmal nocturnal haemoglobinuria (PNH) erythrocytes. DAF appears to be totally deficient in the Inab erythrocytes as judged by immunochemical and functional assays. Unlike PNH, the only other described DAF deficiency (where several other phosphatidylinositol (PI)-linked membrane proteins are also absent), the only protein lacking from Inab erythrocytes appears to be DAF. The Inab phenotype seems to be an inherited specific defect in DAF whereas PNH is an acquired defect in the mechanism of insertion of PI-linked proteins into cell membranes. These findings support the view that susceptibility of PNH erythrocytes to in vivo and in vitro complement-mediated haemolysis is not due simply to DAF deficiency but to either the combined lack of several membrane proteins or to deficiency of other regulatory proteins such as the membrane attack complex inhibitor/homologous restriction factor (MIP/HRF). The findings also raise questions as to the role of erythrocyte DAF.

Children surviving certain cancers have a high incidence of cognitive deficits caused by central nervous system (CNS) disease or treatments directed at the CNS. To establish the feasibility of using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to study cognitive deficits in survivors of childhood cancer, we tested the hypothesis that this population has the same BOLD response to visual stimulation as healthy subjects. We used BOLD fMRI to measure spatial and temporal patterns of brain activity after brief visual stimulation in 16 survivors of childhood cancer, 11 age-similar healthy siblings of survivors, and 16 healthy adults. Functional data for the survivors were analyzed with two general linear models, one used a canonical hemodynamic response function (HRF) and the other used a Fourier set as basis functions. The measured BOLD signal and brain activation patterns were similar in the survivors with both models. The BOLD signal for survivors was qualitatively similar in timing and shape, but there were significant quantitative differences as compared with healthy subjects. The activation was normally located in the primary visual cortex in 13 survivors, but the activation volume was significantly smaller in brain tumor survivors than in other groups. These findings demonstrate the feasibility of using BOLD fMRI to investigate brain function in survivors of childhood cancer. However, fMRI studies in this population must take into account effects of quantitative differences in their BOLD responses as compared to healthy subjects.

Nonlinear coordination is an essential property of the complex functioning of the autonomic nervous system. Therefore, the coupled behavior of heart rate fluctuations (HRF) and respiratory movements (RM) was analyzed on the basis of their joint reconstruction in the phase space. Independence measures of complexity and predictability were approximated from the correlation integrals which enabled the strength of cardiorespiratory couplings to be quantified. These measures were validated in a simulation study of two coupled nonlinear oscillators in dependence on their coupling strength and respective synchronization effects. The cardiorespiratory coordination during quiet sleep and active sleep of newborn piglets was quantified by means of the proposed independence measures of complexity and predictability. The difference of those measures between the sleep states investigated was more significant than the difference of the respective linear coherence peaks.

Differential techniques have revealed several novel genes and peptides involved in trophoblast development including PL74/gdf15/MIC-1, a TGFbeta family cytokine that controls apoptosis and differentiation, PL48, a new serine-threonine protein kinase, serum and glucocorticoid-induced kinase, PBK-1, a tunicamycin-responsive gene, a cathepsin D-like gene (DAP-1) and hypoxia- regulated genes HRF-1,2,6,8 and HIF-1alpha, HIF-1beta, and hEPAS-1. Syncytin, a cell fusion- inducing gene, has been cloned from placenta where it regulates cell fusion. ERV-3 has also been demonstrated to promote cell fusion. These two genes represent the first demonstrated functions of endogenous retroviral sequences in human tissues. Endoglin, PlGF, TGFbeta3, IGF-II, IGFBP-1, and a placental IGFBP protease have found new roles in regulating cytotrophoblast proliferation and invasiveness. A specific placental p105 rasGAP protein has been identified. The homeobox genes DLX4, HB24, MSX2 and MOX2 also likely play a role in development at the epithelial-mesenchymal boundary. Transcription factors such as TEF-5, Hand1, HEB, HASH-2 and two genes represented by ESTs may have regulatory roles in placental development. Evidence suggests that the placenta has an unusual two-cell system for apoptosis regulation in which the cytotrophoblast may direct later apoptotic events in the syncytium, and with syncytialization possibly triggered by the "phosphatidylserine flip". Thus, the placenta is both a rich source of new growth-regulatory substances, and a model system for originating new paradigms of developmental biology.

Homeobox-containing genes play an essential role in basic processes during embryogenesis and development, but little is known about the regulation of their expression. To elucidate regulatory networks that govern homeobox gene expression, we defined the core promoter of the mouse Gax homeobox gene and characterized its interactions with cellular proteins. Transient transfection experiments revealed Gax promoter activity in several cell types. Deletion analysis defined a 138-bp minimal promoter fragment between positions -125 and +13 relative to the transcription initiation site. Mutagenesis and protein-DNA binding assays suggested that at least three positive factors interact with this fragment and are required for transcriptional activity. One of these factors, HRF-1, recognizes a cis element consisting of an inverted palindromic motif. A second factor is Sp1, that binds to a G/C-rich element. The third is the MADS box factor referred to as MEF2 or RSRF. Mutations in the MEF2/RSRF site had the greatest effect on transcription in cell types that expressed the highest levels of endogenous MEF2 activity. Conversely, overexpression of MEF2A transactivated the Gax promoter more efficiently in cells lacking endogenous MEF2. These data provide evidence for a direct transcriptional link between members of the MADS and homeobox families of transcription factors.

BACKGROUND

Previous studies show that clinical features at presentation, in retinoblastoma patients, like glaucoma and neovascularization of iris are associated with a higher incidence of high risk histopathology findings (HRF) in enucleated eyes. Herein, we analyze association between clinical features at time of enucleation and occurrence of HRF including invasion of anterior chamber, iris, ciliary body, choroid (massive), sclera, extrascleral tissue, optic nerve beyond lamina cribrosa, and optic nerve cut end, in a large series of eyes enucleated for retinoblastoma.

METHODS

We retrospectively studied demographic, clinical, and histopathology findings in all retinoblastoma patients who underwent primary enucleation at our center, over a 5 years duration. Statistical analysis was done to find any association between clinical features at presentation and the presence of HRF.

RESULTS

Three hundred twenty-six eyes were studied. Median age of presentation was 2 years. Glaucoma was the most common clinical finding at presentation apart from leucocoria. Out of 326 enucleated eyes, 28 (8.6%) had extrascleral and/or optic nerve transection invasion. Among remaining 298 eyes, with completely resected tumor, 115 (38.6%) had massive choroidal invasion, 54 (17%) had retrolaminar optic nerve invasion, and 24 (7%), 29 (9%), and 23(7%) had anterior chamber, iris, and ciliary body invasion, respectively. Age more than 2 years, lag period more than 3 months, hyphema, pseudohypopyon, staphyloma, and orbital cellulitis were associated with occurrence of three or more HRF on univariate analysis.

CONCLUSIONS

Clinical variables including older age, longer lag period, hyphema, pseudohypopyon, staphyloma, and orbital cellulitis were strongly associated with occurrence of HRF in this study.