Cryptococcal pneumonia and meningitis in a renal transplant recipient with a false negative serum cryptococcal antigen due to postzone phenomenon

Cryptococcal infection can cause significant morbidity and mortality in immunocompromised patients. We present a patient who was diagnosed with cryptococcal meningitis and pulmonary disease in the setting of a history of renal transplantation. The diagnosis was made based on growth of Cryptococcus neoformans in blood cultures and identification of cryptococcal antigen (CrAg) in cerebral spinal fluid (CSF) using a lateral flow assay (LFA). Our case is unique since the initial serum CrAg was falsely negative due to excess cryptococcal antigen preventing the formation of antigen-antibody complexes, referred to as the postzone phenomenon. This phenomenon has been reported on CSF samples but rarely reported on serum samples in patients without an HIV diagnosis.

105. Null Effect of Financial Incentives or Social Media Support on Prep Adherence in a Randomized Controlled Trial of Young Men Who Have Sex with Men of Colour

Background

Pre-exposure prophylaxis (PrEP) using emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) effectively reduces HIV transmission, with efficacy being dependent on adherence. We evaluated the effect of either social media-based support or financial incentives on PrEP adherence among young MSM of color in Washington, DC

Methods

MSM aged 18–29 were randomized 1:1:1 to standard of care (SOC) PrEP (Control group), SOC PrEP + invitation to a bidirectional Facebook group supervised by two clinicians (Social Media group), or SOC PrEP + $50 gift card at each of two follow-up visits (Financial Incentive group). Participants were asked to return at 3 and 6 months. Adherence was monitored with predefined dried blood spots (DBS) TFVdp levels with < 490, 490–979, 980–1749 and ≥1750 fmol/punch correlating with average of < 2, 2–4, 4–6, and 7 doses per week

Results

We enrolled 53 MSM. Average age was 22.5 years and 72% of participants were Black. At enrollment, 96% had previously heard of PrEP, 17% had ever taken PrEP but none had taken PrEP in the prior 6 months. 92% of participants reported condomless anal sex in the prior 3 months, 36% with an HIV-positive man or man of unknown HIV status (Table 1). 81% of participants returned for their 3-month visit and 70% for their 6-month visit. Mean self-reported PrEP adherence over the previous 3 months was 78% with no difference in adherence between the three groups at either visit. Based on DBS TFVdp levels, protective PrEP adherence (≥4 doses/week) was measured in 46% of the Financial Incentive group and in 57% of the Social Media group compared to in 67% of the Control group (p=0.38). Only 16% of TFVdp levels corresponded to taking PrEP 7 days a week (Figure 1). There was no change in sexual risk activity over the course of the study. 38 sexually transmitted infections were diagnosed in 26 participants (Figure 2). No participant tested positive for HIV. 3 months after study completion, 9 participants were still taking PrEP

Table I. Sexual risk behaviors over the previous 3 months for study participants assessed at baseline visit, as well as 3 month and 6 month follow up visits

Figure 1. PrEP Adherence.

Figure 2. Number of sexually transmitted infections by specific etiology and site diagnosed

Conclusion

Our study showed no impact of either offering financial incentives or providing access to a supervised Facebook-based support group on PrEP adherence. Financial compensation based on level of PrEP adherence and using a more age-appropriate social media platform may have a greater impact on adherence

Disclosures

All Authors: No reported disclosures

1275. Factors Associated with Patient-Provider Discussions about Preexposure Prophylaxis Among Young Men Who Have Sex with Men in Washington, DC

Background

The CDC estimates that 1.2 million people in the United States are eligible for HIV pre-exposure prophylaxis (PrEP). However, only about 120,000 people have received PrEP prescriptions through 2017. Healthcare providers’ (HCP) willingness to engage patients in discussions regarding sexual health, including PrEP, is integral to increasing PrEP uptake in the United States. Our objective was to identify factors associated with patients having discussions about PrEP with their HCP.

Methods

Men who have sex with men (MSM) aged 16–25 in the Washington, DC metro area recruited from the community completed a web-based survey in 2016 about their perceptions of and experiences with PrEP. We used multivariable logistic regression to calculate adjusted odds ratios (aOR) for associations between sociodemographic characteristics (including: age, race/ethnicity, insurance, student/employment status, education, income, living arrangements, social support, depressive symptoms) and patient-provider discussions, including willingness to have or ever having a discussion about PrEP.

Results

Among 239 MSM, 51% were Black, 25% were White, and 16% were Hispanic. 154 participants (65%) were willing to ask a HCP about PrEP without their HCP bringing it up. 159 participants (67%) reported that a HCP had never talked to them about PrEP, although 100 of the 159 (63%) expressed interest in discussing PrEP with a HCP. Participants aged <21 were less willing to ask a HCP about PrEP (aOR: 0.49, 95% CI 0.28–0.85) and insured participants were more willing to ask their HCP about PrEP (aOR: 3.64, 95% CI 1.42–9.33). In multivariable analyses, no sociodemographic characteristics were associated with having talked to a HCP about PrEP, and among those who had never talked to a HCP about PrEP, no characteristics were associated with wanting to do so.

Conclusion

There is a need to increase PrEP uptake in populations at high risk for HIV exposure. While MSM >21 and those with health insurance were more willing to ask their HCP about PrEP, there were no other differences across multiple demographic groups. Our study suggests that a wide PrEP engagement strategy that encourages HCPs to address PrEP with their patients regardless of their demographics would be beneficial to increase PrEP uptake.

Disclosures

All authors: No reported disclosures.

Patients' and Clinicians' Perceptions of Antibiotic Prescribing for Upper Respiratory Infections in the Acute Care Setting

Reducing inappropriate prescribing is key to mitigating antibiotic resistance, particularly in acute care settings. Clinicians' prescribing decisions are influenced by their judgments and actual or perceived patient expectations. Fuzzy trace theory predicts that patients and clinicians base such decisions on categorical gist representations that reflect the bottom-line understanding of information about antibiotics. However, due to clinicians' specialized training, the categorical gists driving clinicians' and patients' decisions might differ, which could result in mismatched expectations and inefficiencies in targeting interventions. We surveyed clinicians and patients from 2 large urban academic hospital emergency departments (EDs) and a sample of nonpatient subjects regarding their gist representations of antibiotic decisions, as well as relevant knowledge and expectations. Results were analyzed using exploratory factor analysis (EFA) and multifactor regression. In total, 149 clinicians (47% female; 74% white), 519 online subjects (45% female; 78% white), and 225 ED patients (61% female; 56% black) completed the survey. While clinicians demonstrated greater knowledge of antibiotics and concern about side effects than patients, the predominant categorical gist for both patients and clinicians was "why not take a risk," which compares the status quo of remaining sick to the possibility of benefit from antibiotics. This gist also predicted expectations and prior prescribing in the nonpatient sample. Other representations reflected the gist that "germs are germs" conflating bacteria and viruses, as well as perceptions of side effects and efficacy. Although individually rational, reliance on the "why not take a risk" representation can lead to socially suboptimal results, including antibiotic resistance and individual patient harm due to adverse events. Changing this representation could alter clinicians' and patients' expectations, suggesting opportunities to reduce overprescribing.

Pharmacogenetic neuronal stimulation increases human tau pathology and trans-synaptic spread of tau to distal brain regions in mice

In Alzheimer's Disease (AD), tau pathology has a spatiotemporally distinct pattern of progressive spread along anatomically connected neural pathways. Extracellular tau in the brain interstitial space increases in response to neuronal activity suggesting that neural activity may also drive pathogenic tau spread. Here we tested the hypothesis that neuronal activity drives human Tau (hTau) release and trans-synaptic spread to neuroanatomically connected regions. We used AAV to overexpress wild type full-length hTau and an excitatory DREADD (Designer Receptors Exclusively Activated by a Designer Drug) in mouse primary hippocampal cultures and determined that excitatory stimulation with the DREADD ligand clozapine N-oxide (CNO) promoted extracellular hTau release. We translated this approach to an in vivo model and used AAV to express hTau and the excitatory DREADD in the ventral hippocampus of wild type mice, P301L hTau-expressing mice, or tau knockout mice. Six to eight weeks following AAV injection, we determined that CNO treatment in DREADD-expressing mice resulted in increased hTau pathology and hTau spread to distal brain regions compared to unstimulated controls (CNO in non-DREADD mice, or vehicle in DREADD mice). The results highlight a potentially disease relevant exacerbation of tau pathology in response to elevated neuronal activity. This model underscores the propensity of non-mutant hTau to undergo neuronal spreading, as seen in AD. The model can translate to other preclinical species and can be used to evaluate modes of tau transmission and test the efficacy of therapeutic approaches that target tau or hyperexcitability.

Edwardsiella ictaluri infection in Pangasius catfish imported from West Bengal into the Southern Caribbean

In response to a mortality event, seven Pangasius catfish (Pangasianodon hypophthalmus) were submitted to the University of the West Indies, School of Veterinary Medicine, Trinidad and Tobago, for diagnostic evaluation. These fish were part of a consignment that arrived from Kolkata two weeks earlier. Fish presented with perianal haemorrhage and blister-like swellings on the skin which ruptured to leave ulcers. Edwardsiella ictaluri was consistently recovered from the brain and skin. Repetitive sequence-mediated PCR analysis revealed genetic fingerprints consistent with E. ictaluri isolates from farm-raised channel catfish in Mississippi, USA. Plasmid analysis of the case isolates identified two unique plasmids that differ slightly in conformation and content from the pEI1 and pEI2 plasmids described for E. ictaluri from other fish hosts. The case isolates were also PCR negative for several E. ictaluri virulence factors. The biological implications of these genetic differences are unclear and warrant further study. This is the first report and documentation of E. ictaluri infection in Trinidad and Tobago, suggesting the pathogen may have been introduced concurrently with the importation of fish. This report emphasizes the importance of adequate health screenings of imported lots to minimize the threat of introducing E. ictaluri to non-endemic areas.

Comparison of Edwardsiella ictaluri isolates from different hosts and geographic origins

The intraspecific variability of E. ictaluri isolates from different origins was investigated. Isolates were recovered from farm-raised catfish (Ictalurus punctatus) in Mississippi, USA, tilapia (Oreochromis niloticus) cultured in the Western Hemisphere and zebrafish (Danio rerio) propagated in Florida, USA. These isolates were phenotypically homologous and antimicrobial profiles were largely similar. Genetically, isolates possessed differences that could be exploited by repetitive-sequence-mediated PCR and gyrB sequence, which identified three distinct E. ictaluri genotypes: one associated with catfish, one from tilapia and a third from zebrafish. Plasmid profiles were also group specific and correlated with rep-PCR and gyrB sequences. The catfish isolates possessed profiles typical of those described for E. ictaluri isolates; however, plasmids from the zebrafish and tilapia isolates differed in both composition and arrangement. Furthermore, some zebrafish and tilapia isolates were PCR negative for several E. ictaluri virulence factors. Isolates were serologically heterogenous, as serum from a channel catfish exposed to a catfish isolate had reduced antibody activity to tilapia and zebrafish isolates. This work identifies three genetically distinct strains of E. ictaluri from different origins using rep-PCR, 16S, gyrB and plasmid sequencing, in addition to antimicrobial and serological profiling.

Transcriptional repression of IFNβ1 by ATF2 confers melanoma resistance to therapy

The resistance of melanoma to current treatment modalities represents a major obstacle for durable therapeutic response, and thus, the elucidation of mechanisms of resistance is urgently needed. The crucial functions of Activating Transcription Factor-2 (ATF2) in the development and therapeutic resistance of melanoma have been previously reported, although the precise underlying mechanisms remain unclear. Here, we report a protein kinase C epsilon (PKCε)- and Activating Transcription Factor-2 (ATF2)-mediated mechanism that facilitates resistance by transcriptionally repressing the expression of IFNβ1 and downstream type-I IFN signaling, which is otherwise induced upon exposure to chemotherapy. Treatment of early stage melanomas expressing low levels of PKCε with chemotherapies relieves its transcriptional repression of IFNB1, resulting in impaired S-phase progression, a senescence-like phenotype, and increased cell death. This response is lost in late stage metastatic melanomas expressing high levels of PKCε. Notably, nuclear ATF2 and low expression of IFNβ1 in melanoma tumor samples correlates with poor patient responsiveness to biochemotherapy or neoadjuvant IFN-α2a. Conversely, cytosolic ATF2 and induction of IFNβ1 coincides with therapeutic responsiveness. Collectively, we identify an IFNβ1-dependent, cell autonomous mechanism that contributes to the therapeutic resistance of melanoma via the PKCε-ATF2 regulatory axis.

Gamma-secretase inhibitors target tumor-initiating cells in a mouse model of ERBB2 breast cancer

Human breast tumors comprise a minor sub-population of tumor-initiating cells (TICs), commonly termed cancer stem cells. TICs are thought to sustain tumor growth and to confer resistance to current anticancer therapies. Hence, targeting TIC may be essential to achieving durable cancer cures. To identify molecular targets in breast TIC, we employed a transgenic mouse model of ERBB2 breast cancer; tumors arising in this model comprise a very high frequency of TIC, which is maintained in tumor cell populations propagated in vitro as non-adherent tumorspheres. The Notch pathway is dysregulated in human breast tumors and overexpression of constitutively active Notch proteins induces mammary tumors in mice. The Notch pathway has also been implicated in stem cell processes including those of mammary epithelial stem cells. Hence, we investigated the potential that the Notch pathway is required for TIC activity. We found that an antagonist of Notch signaling, a gamma (γ)-secretase inhibitor termed MRK-003, inhibited the survival of tumorsphere-derived cells in vitro and eliminated TIC as assessed by cell transplantation into syngeneic mice. Whereas MRK-003 also inhibited the self-renewal and/or proliferation of mammosphere-resident cells, this effect of the inhibitor was reversible thus suggesting that it did not compromise the survival of these cells. MRK-003 administration to tumor-bearing mice eliminated tumor-resident TIC and resulted in rapid and durable tumor regression. MRK-003 inhibited the proliferation of tumor cells, and induced their apoptosis and differentiation. These findings suggest that MRK-003 targets breast TIC and illustrate that eradicating these cells in breast tumors ensures long-term, recurrence-free survival.

Down-regulation of the Notch pathway mediated by a gamma-secretase inhibitor induces anti-tumour effects in mouse models of T-cell leukaemia

BACKGROUND AND PURPOSE

gamma-Secretase inhibitors (GSIs) block NOTCH receptor cleavage and pathway activation and have been under clinical evaluation for the treatment of malignancies such as T-cell acute lymphoblastic leukaemia (T-ALL). The ability of GSIs to decrease T-ALL cell viability in vitro is a slow process requiring >8 days, however, such treatment durations are not well tolerated in vivo. Here we study GSI's effect on tumour and normal cellular processes to optimize dosing regimens for anti-tumour efficacy.

EXPERIMENTAL APPROACH

Inhibition of the Notch pathway in mouse intestinal epithelium was used to evaluate the effect of GSIs and guide the design of dosing regimens for xenograft models. Serum Abeta(40) and Notch target gene modulation in tumours were used to evaluate the degree and duration of target inhibition. Pharmacokinetic and pharmacodynamic correlations with biochemical, immunohistochemical and profiling data were used to demonstrate GSI mechanism of action in xenograft tumours.

KEY RESULTS

Three days of >70% Notch pathway inhibition was sufficient to provide an anti-tumour effect and was well tolerated. GSI-induced conversion of mouse epithelial cells to a secretory lineage was time- and dose-dependent. Anti-tumour efficacy was associated with cell cycle arrest and apoptosis that was in part due to Notch-dependent regulation of mitochondrial homeostasis.

CONCLUSIONS AND IMPLICATIONS

Intermittent but potent inhibition of Notch signalling is sufficient for anti-tumour efficacy in these T-ALL models. These findings provide support for the use of GSI in Notch-dependent malignancies and that clinical benefits may be derived from transient but potent inhibition of Notch.

197 PRODUCTION OF IN VITRO- AND IN VIVO-DERIVED CAT BLASTOCYSTS FOR THE ESTABLISHMENT OF FELINE EMBRYONIC STEM CELLS

Identification and characterization of spontaneously occurring genetic diseases in cats has permitted the development of valuable models for testing potential treatments of similar human diseases. With the near completion of the feline genome project, establishment of pluripotential feline embryonic stem (ES) cells would facilitate the targeting of specific genetic loci to produce new feline medical models. Two approaches were used to produce feline blastocysts in an attempt to establish feline ES cells in culture. Naive queens were superovulated with an intramuscular (i.m.) injection of 150 IU of equine chorionic gonadotropin (eCG) followed by an i.m. injection of 100 IU of human chorionic gonadotropin (hCG) 80 h later; follicles were aspirated laparoscopically 24-26 h later for subsequent in vitro fertilization (IVF). On average, 29 mature cumulus oocyte cell complexes (COCs) were recovered from each queen. IVF was performed in 50 microliter drops of complete Hams F-10 medium containing 30 000 fresh, motile sperm. COCs were cultured overnight in 5% carbon dioxide at 38�C, and residual adherent cumulus cells were removed 12 to 16 h later by trituration in 0.1% hyaluronidase. Embryos were cultured in fresh drops of Hams F-10, and on average 25% developed to the early blastocyst stage after 7 days. Alternatively, estrus was induced in queens with a single i.m. injection of 100 IU of eCG, and then 72 h later queens were permitted six supervised matings with a fertile tom over the next two days. Queens underwent ovariohysterectomy 7 days after their first copulation, and compacted morulae and early blastocysts were flushed from the oviducts and uterine horns. On average, eight embryos were recovered from the reproductive tract of each queen. Both in vivo- and in vitro-matured blastocysts were subsequently cultured in standard mouse ES cell medium on inactivated mouse embryonic fibroblasts. When they failed to hatch in culture after 3 days, a 0.5% pronase solution was used to dissolve the zonae pellucidae under microscopic visualization. Denuded expanded blastocysts adhered to the heterotypic feeder layer and primary inner cell mass (ICM) outgrowths formed within 4 days. Outgrowths were mechanically disaggregated into small clusters of 15 to 20 cells and re-plated on fresh feeders. These colonies grew slowly and were transferred after one week onto new feeder layers. The addition of murine or human recombinant leukemia inhibitory factor had no effect on the survival and proliferation of primary outgrowths or subsequent colonies. After 3 weeks, all colonies derived from both in vivo- and in vitro-matured blastocysts had either differentiated or died. Additional experiments are ongoing to test the effects of homotypic feeder layers and alternative growth factors on promoting the establishment and survival of feline ES cell lines. Ultimately, germline transmission of any putative feline ES cell lines will need to be demonstrated in vivo for their utility in gene targeting experiments to be realized.

83ANALYSIS OF RAPID COOLING V. SLOW COOLING COMBINED WITH ICE CRYSTAL SEEDING FOR CRYOPRESERVATION OF PRIMATE EMBRYONIC STEM CELLS

Primate embryonic stem (ES) cells have the ability to self-renew indefinitely while maintaining the ability to differentiate. This unique property allows scientists to study the factors necessary for stem cell self-renewal and differentiation in vitro that reflect in vivo processes. Work with primate ES cells is handicapped by the poor survival (1–5%) of rhesus and human ES cells following standard tissue culture methods of rapid cryopreservation. The purpose of this study was to compare and contrast two cryopreservation techniques, slow cooling combined with ice crystal seeding commonly used for mammalian embryos v. rapid cooling commonly used for tissue culture, to find a method for efficient primate ES cell cryopreservation. A combination of trials was run to compare dimethyl sulfoxide (DMSO) v. ethylene glycol as a cryoprotectant, a cooling rate of 0.3°C per minute following ice crystal seeding at −7°C v. placement at −80°C with no seeding, and rapid thaw with step-wise cryoprotectant removal v. one-step sucrose cryoprotectant removal. Cell survival was assessed through a combination of cell surface markers, alkaline phosphatase staining and morphology to look for undifferentiated cells and quantitate survival. All cryopreservations were performed with the same cell density. The survival of the cells with slow embryo-style cooling in DMSO with a step-wise cryoprotectant removal was 64.0% v. 12.8% with rapid cooling.

Transgenic and gene-targeted mouse lines for toxicology studies

This unit contains an extensive tabular listing of transgenic and gene-targeted mice useful in toxicological studies. Each listing contains a brief description of the phenotype, relevant references, and where applicable, commercial sources.

Hepatitis C virus core protein binds to the cytoplasmic domain of tumor necrosis factor (TNF) receptor 1 and enhances TNF-induced apoptosis

The hepatitis C virus (HCV) core protein is known to be a multifunctional protein, besides being a component of viral nucleocapsids. Previously, we have shown that the core protein binds to the cytoplasmic domain of lymphotoxin beta receptor, which is a member of tumor necrosis factor receptor (TNFR) family. In this study, we demonstrated that the core protein also binds to the cytoplasmic domain of TNFR 1. The interaction was demonstrated both by glutathione S-transferase fusion protein pull-down assay in vitro and membrane flotation method in vivo. Both the in vivo and in vitro binding required amino acid residues 345 to 407 of TNFR 1, which corresponds to the "death domain" of this receptor. We have further shown that stable expression of the core protein in a mouse cell line (BC10ME) or human cell lines (HepG2 and HeLa cells) sensitized them to TNF-induced apoptosis, as determined by the TNF cytotoxicity or annexin V apoptosis assay. The presence of the core protein did not alter the level of TNFR 1 mRNA in the cells or expression of TNFR 1 on the cell surface, suggesting that the sensitization of cells to TNF by the viral core protein was not due to up-regulation of TNFR 1. Furthermore, we observed that the core protein blocked the TNF-induced activation of RelA/NF-kappaB in murine BC10ME cells, thus at least partially accounting for the increased sensitivity of BC10ME cells to TNF. However, NF-kappaB activation was not blocked in core protein-expressing HeLa or HepG2 cells, implying another mechanism of TNF sensitization by core protein. These results together suggest that the core protein can promote cell death during HCV infection via TNF signaling pathways possibly as a result of its interaction with the cytoplasmic tail of TNFR 1. Therefore, TNF may play a role in HCV pathogenesis.

Three dimensional imaging of the Belousov-Zhabotinsky reaction using magnetic resonance

The combination of 3D magnetic resonance imaging data with polygon based computer graphic display software is ideally suited to the study of the Belousov-Zhabotinsky reaction in extended volumes. In this paper we present the first true three dimensional visualization of experimental data from the Belousov-Zhabotinsky reaction. The time evolution of a twisted scroll wave like isoconcentration surface and its organizing filament are demonstrated for the manganese-catalyzed B-Z mixture. These techniques extend the experimental study of the B-Z reaction as a class of pattern-forming systems to the third dimension. The limitations of the technique are discussed.

Paracetamol self-poisoning. Characteristics, prevention and harm reduction

BACKGROUND

Paracetamol is now the most common drug used for self-poisoning in the UK and is associated with potentially fatal liver damage. Patients admitted to hospital because of paracetamol overdoses were studied in order to determine their characteristics and factors which might have deterred them from taking paracetamol or reduced the dangers of the overdose.

METHOD

Eighty patients were studied in hospital using a structured interview schedule, measures of depression and suicidal intent, information collected through the Oxford Monitoring System for Attempted Suicide, and the results of liver function tests.

RESULTS

Acute liver dysfunction (25 patients) was associated with consumption of more than 25 tablets (odds ration 4.46, 95% CI 1.31 to 17.41, P = 0.014). The proportionate use of tablets from blister packs (60%) and loose preparations (46%; 5 patients using both types) reflected their general availability. More of those who took tablets from a loose preparation consumed 25 or more tablets (69%) than those who used a blister-pack preparation (40%; odds ratio = 3.0, 95% CI 1.12 to 9.95, P = 0.028). Only 20 patients thought that any type of warning label would have deterred them from taking a paracetamol overdose.

CONCLUSIONS

Establishing a maximum number of tablets (e.g. 25) that can be available in individual preparations is likely to reduce the dangers of paracetamol self-poisoning. The potential effects of other measures are uncertain.

The Epstein-Barr virus transforming protein LMP1 engages signaling proteins for the tumor necrosis factor receptor family

The cytoplasmic C-terminus of Epstein-Barr virus (EBV) latent infection membrane protein 1 (LMP1) is essential for B lymphocyte growth transformation and is now shown to interact with a novel human protein (LMP1-associated protein 1 [LAP1]). LAP1 is homologous to a murine protein, tumor necrosis factor receptor-associated factor 2 (TRAF2), implicated in growth signaling from the p80 TNFR. A second novel protein (EBI6), induced by EBV infection, is the human homolog of a second murine TNFR-associated protein (TRAF1). LMP1 expression causes LAP1 and EBI6 to localize to LMP1 clusters in lymphoblast plasma membranes, and LMP1 coimmunoprecipitates with these proteins. LAP1 binds to the p80 TNFR, CD40, and the lymphotoxin-beta receptor, while EBI6 associates with the p80 TNFR. The interaction of LMP1 with these TNFR family-associated proteins is further evidence for their role in signaling and links LMP1-mediated transformation to signal transduction from the TNFR family.

Purple glove syndrome

Purple glove syndrome (PGS) often begins with discoloration and progresses to a petechial rash with induration or evidence of infiltration. The etiology of PGS is unknown, although various theories center around i.v. extravasation. We report a case of PGS in a child's foot associated with administration of Dilantin (phenytoin).

Evidence for an independent luminance channel

There is a discrepancy between several studies that have shown the human luminous-efficiency function to vary with surround color and a recent study that failed to find this dependence. Data are presented that show that this discrepancy can be explained by differences in the matching techniques. Luminous efficiency measured by direct heterochromatic brightness matching does depend on surround color, whereas luminous efficiency measured by the flicker method does not. The independence of luminous efficiency as measured by flicker is evidence for an independent luminance channel.

Reactions to the implantation of an inflatable penile prosthesis among psychogenically and organically impotent men

We evaluated 17 nondepressed and psychologically stable recipients of an inflatable penile prosthesis who had been either organically or psychogenically impotent and 12 of their sexual partners several months after surgical implantation. The men were evaluated for changes in general psychological adjustment, sexual satisfaction and sexual activity. The partners were assessed separately on similar instruments. Two scales of the Minnesota Multiphasic Personality Inventory were found to have potential for initially discriminating organic and psychogenic impotence. The hypothesis that psychogenic recipients would manifest more psychological difficulties and would be less satisfied was only partially supported. While neither group suffered significant disturbance in psychological adjustment a consistent pattern was noted in which psychogenic patients were somewhat less satisfied with the results and experienced more postoperative complications. However, over-all reactions were positive, including increases in frequency of sexual over-all reactions were positive, including increases in frequency of sexual intercourse and duration of sexual play for patients and their partners.

The chromatic Cornsweet effect

The Cornsweet effect was measured using equiluminous chromatic gradients as well as with an achromatic gradient. The chromatic Cornsweet effect is smaller than the achromatic effect.

Human axial chromatic aberration found not to decline with age

Millodot (1976) reported a dramatic decline in the amount of axial chromatic aberration of the human eye with age. The present study represents a failure to replicate that finding using a more standard procedure. No difference in chromatic aberration was found between a young and an older group of observers. Also, the chromatic aberrations of two observers which had been measured 25 years previously showed no decline when these measurements were repeated, even though their ages at first and second testing straddled the period over which Millodot reported the most change in chromatic aberration.

Changes in perceived color due to chromatic interactions

Studies of chromatic induction have generally examined either (a) the effects of a chromatic surround on a neutral test field, or (b) the effects of one spectral hue on another. To investigate how colors interact in other regions of color space an experiment was designed using fifteen test stimuli scattered through C.I.E. color space. The perceived hue of each stimulus was matched on its own and in the presence of five inducing stimuli. Matching was done both with and without a lens to correct axial chromatic aberration, which was found to be a significant prereceptoral factor influencing perceived colour. With chromatic aberration corrected the overall pattern of chromatic changes can be explained neither by receptor processes alone, nor by opponent channel processes alone. But a reasonable fit can be obtained if changes are allowed to take place in both levels of the system.

Coloured illusory triangles due to assimilation

A coloured addition by Varin to Kanizsa's triangle figure gives rise to a colour-tinted illusory triangle. Two theories for this effect are described, (i) a cognitive theory based on perceived transparency and (ii) a theory based on an assimilation mechanism. An experiment is reported which uses certain colour combinations incompatible with transparency and other combinations where the two theories predict different illusory colours. The results support the assimilation theory.

Illusory contours can arise in dot figures

Frisby and Clatworthy have suggested that subjective contours depend on special contrast effects acting at the tips of lines and at right angles to the lines. Their suggestion depends in part on the absence of such contours in dot figures. However, if the dots are grouped regularly and make a 'good figure', strong subjective contours appear, including a pattern comparable to Kaniza's triangle. The kind of contrast explanation required for these figures would be one in which individual dots create small contrast effects which are only manifest in perception when the effects are grouped together, by Gestalt form indicators, overlap cues, or the like.

Illusory line linking solid rods

A solid object--a frame enclosing rods--can be seen as having an illusory 'line' joining the tips of the rods.

Interocular transfer of a visual after-effect in normal and stereoblind humans

1. Following inspection of a high contrast grating a test grating of a slightly different orientation will briefly appear rotated from its true orientation in a direction opposite to that of the adapting grating.2. The extent of interocular transfer of this phenomenon (the tilt after-effect) was measured in a number of normal subjects and in four subjects (three of whom had a strabismus) who lacked stereopsis.3. In contrast to the normal subjects, none of the four stereoblind subjects showed any interocular transfer of the tilt after-effect. Amongst the normal subjects the extent of transfer of this after-effect was positively correlated with the subject's stereoacuity. Maximum transfer (70%) was found in the subject with the best stereoacuity. In many subjects transfer was greater from the dominant eye to the non-dominant eye than vice versa.4. By analogy with experiments on cats deprived of congruent visual input to the two eyes early in life it is argued that the stereoblind subjects lack any binocularly driven cortical neurones.

Clinical and radiological study of vagotomy and gastric drainage in the treatment of pyloric stenosis due to duodenal ulceration

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Leiomyosarcoma of stomach

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Cervical dumb-bell neurilemoma

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