31P magnetic resonance spectroscopy as a predictor of efficacy in photodynamic therapy using differently charged zinc phthalocyanines

Photodynamic therapy (PDT) is a developing approach to the treatment of solid tumours which requires the combined action of light and a photosensitizing drug in the presence of adequate levels of molecular oxygen. We have developed a novel series of photosensitizers based on zinc phthalocyanine which are water-soluble and contain neutral (TDEPC), positive (PPC) and negative (TCPC) side-chains. The PDT effects of these sensitizers have been studied in a mouse model bearing the RIF-1 murine fibrosarcoma line studying tumour regrowth delay, phosphate metabolism by magnetic resonance spectroscopy (MRS) and blood flow, using D2O uptake and MRS. The two main aims of the study were to determine if MRS measurements made at the time of PDT treatment could potentially be predictive of ultimate PDT efficacy and to assess the effects of sensitizer charge on PDT in this model. It was clearly demonstrated that there is a relationship between MRS measurements during and immediately following PDT and the ultimate effect on the tumour. For all three drugs, tumour regrowth delay was greater with a 1-h time interval between drug and light administration than with a 24-h interval. In both cases, the order of tumour regrowth delay was PPC > TDEPC = TCPC (though the data at 24 h were not statistically significant). Correspondingly, there were greater effects on phosphate metabolism (measured at the time of PDT or soon after) for the 1-h than for the 24-h time interval. Again effects were greatest with the cationic PPC, with the sequence being PPC > TDEPC > TCPC. A parallel sequence was observed for the blood flow effects, demonstrating that reduction in blood flow is an important factor in PDT with these sensitizers. © 1999 Cancer Research Campaig

Sub-Telomere Directed Gene Expression during Initiation of Invasive Aspergillosis

Aspergillus fumigatus is a common mould whose spores are a component of the normal airborne flora. Immune dysfunction permits developmental growth of inhaled spores in the human lung causing aspergillosis, a significant threat to human health in the form of allergic, and life-threatening invasive infections. The success of A. fumigatus as a pathogen is unique among close phylogenetic relatives and is poorly characterised at the molecular level. Recent genome sequencing of several Aspergillus species provides an exceptional opportunity to analyse fungal virulence attributes within a genomic and evolutionary context. To identify genes preferentially expressed during adaptation to the mammalian host niche, we generated multiple gene expression profiles from minute samplings of A. fumigatus germlings during initiation of murine infection. They reveal a highly co-ordinated A. fumigatus gene expression programme, governing metabolic and physiological adaptation, which allows the organism to prosper within the mammalian niche. As functions of phylogenetic conservation and genetic locus, 28% and 30%, respectively, of the A. fumigatus subtelomeric and lineage-specific gene repertoires are induced relative to laboratory culture, and physically clustered genes including loci directing pseurotin, gliotoxin and siderophore biosyntheses are a prominent feature. Locationally biased A. fumigatus gene expression is not prompted by in vitro iron limitation, acid, alkaline, anaerobic or oxidative stress. However, subtelomeric gene expression is favoured following ex vivo neutrophil exposure and in comparative analyses of richly and poorly nourished laboratory cultured germlings. We found remarkable concordance between the A. fumigatus host-adaptation transcriptome and those resulting from in vitro iron depletion, alkaline shift, nitrogen starvation and loss of the methyltransferase LaeA. This first transcriptional snapshot of a fungal genome during initiation of mammalian infection provides the global perspective required to direct much-needed diagnostic and therapeutic strategies and reveals genome organisation and subtelomeric diversity as potential driving forces in the evolution of pathogenicity in the genus Aspergillus

A Role for the Unfolded Protein Response (UPR) in Virulence and Antifungal Susceptibility in Aspergillus fumigatus

Filamentous fungi rely heavily on the secretory pathway, both for the delivery of cell wall components to the hyphal tip and the production and secretion of extracellular hydrolytic enzymes needed to support growth on polymeric substrates. Increased demand on the secretory system exerts stress on the endoplasmic reticulum (ER), which is countered by the activation of a coordinated stress response pathway termed the unfolded protein response (UPR). To determine the contribution of the UPR to the growth and virulence of the filamentous fungal pathogen Aspergillus fumigatus, we disrupted the hacA gene, encoding the major transcriptional regulator of the UPR. The ΔhacA mutant was unable to activate the UPR in response to ER stress and was hypersensitive to agents that disrupt ER homeostasis or the cell wall. Failure to induce the UPR did not affect radial growth on rich medium at 37°C, but cell wall integrity was disrupted at 45°C, resulting in a dramatic loss in viability. The ΔhacA mutant displayed a reduced capacity for protease secretion and was growth-impaired when challenged to assimilate nutrients from complex substrates. In addition, the ΔhacA mutant exhibited increased susceptibility to current antifungal agents that disrupt the membrane or cell wall and had attenuated virulence in multiple mouse models of invasive aspergillosis. These results demonstrate the importance of ER homeostasis to the growth and virulence of A. fumigatus and suggest that targeting the UPR, either alone or in combination with other antifungal drugs, would be an effective antifungal strategy

Sexual partner characteristics, serodiscordant/serostatus unknown unprotected anal intercourse and disclosure among human immunodeficiency virus-infected and uninfected black men who have sex with men in New York city

Objectives: Black men who have sex with men (MSM) are disproportionately infected with human immunodeficiency virus (HIV) in the United States. This study describes sexual partner characteristics and disclosure of HIV serostatus and evaluates factors associated with sexual risk behaviors during last sex among black MSM. DESIGN AND Methods: Between 2008 and 2009, 328 black MSM who reported recent unprotected anal intercourse were enrolled in an HIV behavioral intervention study in New York City. Factors associated with serodiscordant/serostatus unknown UAI (defined as having UAI with a partner of different or unknown HIV serostatus) with a male partner during last sex were assessed using logistic regression. Results: A total of 205 HIV-infected and 123 uninfected men were enrolled in this study. Almost all men (91.6%) reported having a black male partner during last sex. About half (47.3%) of men used alcohol and 38.7% used other substances before or during last sex. About two-thirds (68.8%) of participants disclosed their HIV status to their last sex partner, while 57.2% of partners disclosed. In multivariate analysis, meeting a partner on the internet or chat line was associated with serodiscordant/ serostatus unknown UAI during last sex among HIV-infected men. The only factor associated with serodiscordant/serostatus unknown UAI during last sex among HIV-uninfected men was the partner being a non-main partner. Conclusions: A significant proportion of black MSM in this study did not disclose their HIV status. Our data highlight the need for more data on dyadic variables and sexual risk behaviors among black MSM, as well as interventions to encourage communication between partners. © 2011 American Sexually Transmitted Diseases Association All rights reserved

Sociodemographic and risk behavior characteristics associated with unprotected sex with women among black men who have sex with men and women in New York City

The objectives of this cross-sectional study were to compare sociodemographic and risk behavior characteristics between black men who have sex with both men and women (MSMW) and those who have sex with men only (MSMO) and assess factors associated with having any unprotected vaginal and/or anal intercourse (UVAI) with women in the last 3 months. Data from 326 black men who reported recent unprotected anal intercourse with a man in an HIV behavioral intervention study in New York City were analyzed. Baseline characteristics were compared between MSMW and MSMO, and factors associated with having any UVAI in the past 3 months with women among MSMW were evaluated. In total, 26.8% reported having sex with both men and women in the last 3 months. MSMW were less likely to be HIV infected, use amyl nitrates, and have unprotected receptive anal sex with most recent male partner. MSMW were more likely to be over 40 years old and use heroin. A total of 55.6% of MSMW reported having UVAI with women in the last 3 months. Compared to MSMW having only protected sex, MSMW having any UVAI with women were less likely to be HIV infected and to disclose having sex with men to female partners; they were more likely to have greater than four male sex partners in the last 3 months. In conclusion, HIV prevention interventions among black MSMW should directly address the risk of HIV transmission to both their female and male partners. Disclosure of bisexuality to female partners may be an important component of future prevention efforts. © 2012 Taylor & Francis

Lubricant Flow in an Elastohydrodynamic Contact Using Fluorescence

It is well-documented that parameters, such as film thickness and temperature in EHL contacts, can be measured experimentally using a range of techniques include optical interferometry, ultrasonics, capacitance and infrared emission. Considerably less is known, however, about the flow of lubricant through such contacts. Information about lubricant flow would greatly benefit the prediction of friction in machine components. This article describes initial steps to develop fluorescence as a means of observing lubricant flow. An EHL contact was produced between a steel ball and a glass disc and viewed using a fluorescence microscope. The entrained lubricant was dyed using a fluorescent species, so that when illuminated with laser light, a fluorescence intensity map could be viewed. When the contact was fully flooded with dyed lubricant, the fluorescence intensity within the contact correlated well with optical interferometric film thickness measurements under the same conditions. This suggests useful possibilities for mapping film thickness in contacts where conventional optical methods are impractical, such as between rough surfaces and within soft contacts. In order to observe how lubricant flows in an EHL contact, fluorescer-containing lubricant was placed on the out-of-contact track. The boundary between fluorescent and non-fluorescent lubricant was then entrained into the contact and the passage of the boundary through the contact was monitored