Drug users' willingness to encourage social, sexual, and drug network members to receive an HIV vaccine: a social network analysis.

This study examined feasibility of peer-based promotion of HIV vaccination and dyadic correlates to vaccine encouragement in risk- and non-risk networks of drug users (n = 433) in the US. Data were collected on HIV vaccine attitudes, risk compensation intentions, likelihood of encouraging vaccination, and recent (past 6 months) risk (i.e. involving sex and/or injecting drugs) and non-risk (i.e. involving co-usage of noninjected drugs and/or social support) relationships. Willingness to encourage HIV vaccination was reported in 521 and 555 risk- and non-risk relationships, respectively. However, 37 % expressed hesitancy, typically due to fear of side effects or social concerns. Encouragement was often motivated by perceived HIV risk, though 9 % were motivated by risk compensation intentions. In non-risk partnerships, encouragement was associated with drug co-usage, and in risk relationships, with perceived vaccine acceptability and encouragement by the partner. Network-based HIV vaccine promotion may be a successful strategy, but risk compensation intentions should be explored.

Premating isolation is determined by larval rearing substrates in cactophilic Drosophila mojavensis. IX. Host plant and population specific epicuticular hydrocarbon expression influences mate choice and sexual selection.

Sexual signals in cactophilic Drosophila mojavensis include cuticular hydrocarbons (CHCs), contact pheromones that mediate female discrimination of males during courtship. CHCs, along with male courtship songs, cause premating isolation between diverged populations, and are influenced by genotype × environment interactions caused by different host cacti. CHC profiles of mated and unmated adult flies from a Baja California and a mainland Mexico population of D. mojavensis reared on two host cacti were assayed to test the hypothesis that male CHCs mediate within-population female discrimination of males. In multiple choice courtship trials, mated and unmated males differed in CHC profiles, indicating that females prefer males with particular blends of CHCs. Mated and unmated females significantly differed in CHC profiles as well. Adults in the choice trials had CHC profiles that were significantly different from those in pair-mated adults from no-choice trials revealing an influence of sexual selection. Females preferred different male CHC blends in each population, but the influence of host cactus on CHC variation was significant only in the mainland population indicating population-specific plasticity in CHCs. Different groups of CHCs mediated female choice-based sexual selection in each population suggesting that geographical and ecological divergence has the potential to promote divergence in mate communication systems.

Social networks and HCV viraemia in anti-HCV-positive rural drug users.

Although social networks are known to play an important role in drug-using behaviours associated with hepatitis C virus (HCV) infection, literature on social networks and HCV is inconsistent. This exploratory study examined HCV RNA distribution within a social network of anti-HCV-positive non-medical prescription opioid users (NMPOUs) in rural Appalachia. Participants were tested serologically for HCV RNA, and behavioural, demographic, and network data were collected using interview-administered questionnaires. Multivariate analyses were performed using logistic regression. Behavioural and demographic characteristics did not differ by RNA status. In the multivariate model, recent injecting drug users (IDUs) were more likely to be RNA positive [odds ratio (OR) 4·06, 95% confidence interval (CI) 1·04-15·83], and turnover into an IDU's drug network was significantly protective (OR 0·15, 95% CI 0·03-0·75). This is the first study to date to examine HCV distribution in rural NMPOUs from a network perspective and demonstrates that network characteristics significantly contribute to the epidemiology of HCV in this understudied, high-risk population.

Network structure and the risk for HIV transmission among rural drug users.

Research suggests that structural properties of drug users' social networks can have substantial effects on HIV risk. The purpose of this study was to investigate if the structural properties of Appalachian drug users' risk networks could lend insight into the potential for HIV transmission in this population. Data from 503 drug users recruited through respondent-driven sampling were used to construct a sociometric risk network. Network ties represented relationships in which partners had engaged in unprotected sex and/or shared injection equipment. Compared to 1,000 randomly generated networks, the observed network was found to have a larger main component and exhibit more cohesiveness and centralization than would be expected at random. Thus, the risk network structure in this sample has many structural characteristics shown to be facilitative of HIV transmission. This underscores the importance of primary prevention in this population and prompts further investigation into the epidemiology of HIV in the region.

Mate choice opportunity leads to shorter offspring development time in a desert insect.

We describe indirect genetic benefits of mate choice in two allopatric populations of cactophilic Drosophila mojavensis. By manipulating mate choice opportunity, we show that greater mate choice among sexually mature adults leads to shorter offspring egg-to-adult development times; the extent of this reduction was influenced by population origin and by host plant environment. We performed multiple-choice mating trials with individually marked flies to investigate whether differential male mating success was a consequence of female choice, male interaction, or both. We demonstrate that male copulation frequency was not random and instead, was determined by female choice. Virgin females in these trials were no less discriminating than females that had been previously exposed to males. These results suggest that there are indirect benefits of female mate choice that are population and environment specific, consistent with the hypothesis of ecologically influenced 'good genes' sexual selection.

Willingness to pay for drug rehabilitation: implications for cost recovery.

OBJECTIVES: This study estimates the value that clients place on methadone maintenance and how this value varies with the effectiveness of treatment and availability of case management. We provide the first estimate of the price elasticity of the demand for drug treatment. METHODS: We interviewed 241 heroin users who had been referred to, but had not yet entered, methadone maintenance treatment in Baltimore, Maryland. We asked each subject to state a preference among three hypothetical treatment programs that varied across three domains: weekly fee paid by the client out-of-pocket ($5-$100), presence/absence of case management, and time spent heroin-free (3-24 months). Each subject was asked to complete 18 orthogonal comparisons. Subsequently each subject was asked if they likely would enroll in their preferred choice among the set of three. We computed the expected willingness to pay (WTP) as the probability of enrollment times the fee considered in each choice considered from a multivariate logistic model that controlled for product attributes. We also estimated the price elasticity of demand. RESULTS: The median expected fee subjects were willing to pay for a program that offered 3 months of heroin-free time was $7.30 per week, rising to $17.11 per week for programs that offered 24 months of heroin-free time. The availability of case management increased median WTP by $5.64 per week. The price elasticity was -0.39 (S.E. 0.042). CONCLUSIONS: Clients will pay more for higher rates of treatment success and for the presence of case management. Clients are willing to pay for drug treatment but the median willingness to pay falls short of the estimated program costs of $82 per week. Thus a combined approach of user fees and subsidization may be the optimal financing strategy for the drug treatment system.

Male and female rural probationers: HIV risk behaviors and knowledge.

Individuals involved in the criminal justice system are at substantial risk for HIV infection and have elevated rates of AIDS. Offenders under community supervision, such as probationers, have substantially more opportunities to engage in high-risk behaviors than prisoners. Furthermore, probationers in rural areas are at risk because rural areas may be slower to adopt HIV risk-reduction approaches. Consequently, the primary goal of this study is to describe the HIV risk behaviors and level of HIV knowledge of 800 rural felony probationers. Bivariate results indicate that males have substantially greater criminal histories and engage in more substance use risk behaviors than females. Overall, there was minimal and inconsistent use of condoms, but there were no significant differences by gender. Gender differences prevailed in perceived HIV knowledge, with females reporting high levels of perceived HIV knowledge. Multivariate models did not support the hypothesis that perceived knowledge would be a more robust correlate of scores on the HIV Risk Behavior Knowledge Test for males than females. Results suggest that rural residents are not protected from engaging in HIV risk behaviors and future studies should examine gender discrepancies between perceived and actual HIV knowledge among offenders under community supervision.

Gene therapy for murine glycerol kinase deficiency: importance of murine ortholog.

A glycerol kinase (Gyk) knock-out (KO) mouse model permits improved understanding of glycerol kinase (GK) deficiency (GKD) pathogenesis, however, early death of affected mice limits its utility. The purpose of this work was to delay death of affected males to investigate thoroughly their phenotypes. An adenoviral vector carrying the human (Adeno-XGK) or mouse (Adeno-XGyk) GK gene was injected into KO mice within 24 h of birth. Adeno-XGK did not change KO mouse survival time despite liver GK activity greater than 100% of wild type. However, Adeno-XGyk improved KO mouse survival time greater than two-fold. These investigations demonstrate that gene replacement therapy for Gyk KO mice is more efficacious using murine Gyk than human GK. These studies expand our understanding of GKD pathogenesis in the murine model, and show that while murine GKD is more severe than in humans, GKD mice have similar metabolic disturbances to affected humans with hypoglycemia and acidemia.

Is delta-aminolevulinic acid dehydratase rate limiting in heme biosynthesis following exposure of cells to delta-aminolevulinic acid?

Understanding the regulation and control of heme/porphyrin biosynthesis is critical for the optimization of the delta-aminolevulinic-acid (ALA)-mediated photodynamic therapy of cancer, in which endogenously produced protoporphyrin IX (PPIX) is the photosensitizer. The human breast cancer cell line MCF-7, the rat mammary adenocarcinoma cell line R3230AC, the mouse mammary tumor cell line EMT-6 and the human mesothelioma cell line H-MESO-1 were used to study ALA-induced PPIX levels and their relationship to delta-aminolevulinic acid dehydratase (ALA-D) activity in vitro. Incubation of these cell lines with 0.5 mM ALA for 3 h resulted in a significant increase in PPIX accumulation, compared with control cells, but there was no significant change in ALA-D activity. Exposure of cells incubated with ALA to 30 mJ/cm2 of fluorescent light, a dose that would cause a 50% reduction in cell proliferation, did not significantly alter the activity of ALA-D. Increasing the activity of porphobilinogen deaminase (PBGD), the enzyme immediately subsequent to ALA-D, by four- to seven-fold via transfection of cells with PBGD complementary DNA did not alter the activity of ALA-D. However, incubation of cells with various concentrations of succinyl acetone, a potent inhibitor of ALA-D, caused a concomitant decline in both PPIX accumulation and ALA-D activity. These data imply that when cells are exposed to exogenous ALA, ALA-D is an important early-control step in heme/porphyrin biosynthesis and that regulation of PPIX synthesis by this dehydratase may impact the effectiveness of ALA-mediated photosensitization.

Psychosocial and health-related characteristics of religious well-being.

This investigation examined the relationship between religions well-being and eight psychosocial and health-related characteristics. This study assessed the hypothesis that religious well-being is related to overall health. Participants were 462 college students at two separate colleges in the Pacific Northwest. Analysis showed those subjects scoring higher on the measure of religious well-being scored lower on indices like loneliness and hopelessness and higher on self-esteem. Alcohol and drug use also differed significantly between the high and the low, religious well-being groups.

The cancer patient with severe mucositis.

Oropharyngeal mucositis is a painful, often dose-limiting side effect of both radiotherapy and chemotherapy. To reduce the intensity of pain and prevent systemic infection via the compromised mucosa, agents such as antiseptic mouthwashes, anti-ulcer compounds, sodium bicarbonate, saline, and allopurinol have been traditionally used with limited success. The new agents that show promise are granulocyte macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF). However, best results, dosage, and means of administration still have to be determined. Other agents such as sucralfate, tretinoin, glutamine, and misoprostol are also being tested. The results reported from different testing centers are often contradictory and confusing. Basic requirements in prevention and control of mucositis are good oral hygiene, mechanical débridement of the oral tissues, and hydration.

The New York Presbyterian Pediatric Crisis Service.

This paper outlines the structure of the Pediatric Psychiatry Crisis Service at New York Presbyterian Hospital, a service that provides twenty-four hour emergency psychiatric evaluation and intervention to children, adolescents and families in northern Manhattan. Structure and staffing of the service, usage of the service and the presentation of three cases addressing high, moderate and low risk crisis patients are discussed. Finally, future challenges facing the Crisis Service are addressed.

Behçet's disease: dental and oral soft tissue complications.

Behçet's disease is a chronic, multisystem disorder. It has 3 primary components: recurrent inflammations of the eye, ulcerations of the oral mucous membranes, and ulcerations of the genitalia. Diagnosis of Behçet's disease relies mainly on history taking and clinical manifestations. This article describes the oral soft tissue and dental complications and the prosthetic problems encountered in a young patient. If dentists encounter patients with chronic ocular inflammations and recurrent oral mucous membrane ulcers, the index of suspicion should increase.

Effect of estrogenic perturbations on delta-aminolevulinic acid-induced porphobilinogen deaminase and protoporphyrin IX levels in rat Harderian glands, liver, and R3230AC tumors.

The Harderian gland in rodents highly expresses enzymes of the heme biosynthetic pathway that are responsible for porphyrin production. Interestingly, many of the steps in Harderian gland heme biosynthesis, including protoporphyrin production, are controlled hormonally. We hypothesized that estrogenic alterations, ovariectomy or tamoxifen administration, might also alter the response of porphobilinogen deaminase activity and/or protoporphyrin IX production to delta-aminolevulinic acid administration in the hormonally responsive R3230AC rat mammary adenocarcinoma. We also determined whether the response of the R3230AC tumor, borne on ovariectomized hosts, to delta-aminolevulinic acid-based photodynamic therapy was altered compared with tumors treated on intact hosts. Ovariectomy of female Fischer rats bearing the hormonally responsive R3230AC mammary adenocarcinoma caused a significant reduction in delta-aminolevulinic acid-induced protoporphyrin IX levels and porphobilinogen deaminase activity in tumors compared with levels in tumors from intact animals treated with delta-aminolevulinic acid. In contrast, although porphobilinogen deaminase activity in the Harderian gland from ovariectomized animals was reduced significantly compared with that in glands from intact animals, protoporphyrin IX levels were unaltered. Administration of the anti-estrogen tamoxifen to tumor-bearing rats resulted in a significant increase in porphobilinogen deaminase in both tumor and Harderian gland. Although administration of delta-aminolevulinic acid increased protoporphyrin IX levels in Harderian glands in tamoxifen-treated animals, tumor levels of protoporphyrin IX remained unaltered in the tamoxifen-treated rats. Treatment of R3230AC tumors with delta-aminolevulinic acid-based photodynamic therapy in ovariectomized rats resulted in a significantly reduced response compared with the same treatment regimen in intact animals, 4.9+/-0.39 versus 10.6+/-0.6 days to reach twice the initial tumor volume, respectively. These results indicate that the hormonal status of the host should be considered when treating hormonally sensitive tumors with delta-aminolevulinic acid-based photodynamic therapy.

Relationship of delta-aminolevulinic acid-induced protoporphyrin IX levels to mitochondrial content in neoplastic cells in vitro.

Protoporphyrin IX, induced by the exogenous addition of delta-aminolevulinic acid, reaches different levels in different tumor cells. Because many of the steps in heme biosynthesis, of which protoporphyrin IX is penultimate, are located in the mitochondria, we surmised that the mitochondrial content of cells may relate to the amount of protoporphyrin IX synthesized in response to excess delta-aminolevulinic acid. We observed that accumulation of MitoTracker, a fluorescent mitochondrial probe, delta-aminolevulinic acid-induced protoporphyrin IX levels, and porphobilinogen deaminase activity all presented with the same cell-line-dependent rank order among the four different neoplastic cells. This rank order, however, differed for cytochrome c oxidase activity, the final enzyme in mitochondrial electron transport, and for accumulation of radioactive label from [(14)C]delta-aminolevulinic acid. The data demonstrate that enzymes involved in heme biosynthesis, in general, display a rank order associated with mitochondrial content. These data imply that such parameters may have value as prognosticators of cells to produce delta-aminolevulinic acid-induced protoporphyrin IX, a photosensitizer for photodynamic therapy of cancer.

Effect of delta-aminolevulinic acid on protoporphyrin IX accumulation in tumor cells transfected with plasmids containing porphobilinogen deaminase DNA.

Recently, we reported that the delta-aminolevulinic acid (delta-ALA)-induced increase in porphobilinogen deaminase (PBGD) activity was closely correlated with an increase in the accumulation of protoporphyrin IX (PPIX), resulting in augmented phototoxicity. In this report, we asked whether increasing the cellular expression of PBGD by use of gene transfection techniques in vitro would further enhance delta-ALA-induced PPIX accumulation and hence, phototoxicity. For these experiments we constructed plasmid vectors containing the PBGD-DNA, using a reverse transcription-polymerase chain reaction-generated cDNA fragment encoded from its published sequence. Subsequently, transfection of the human mammary tumor cell line, MCF-7, and the human mesothelioma cell line, H-MESO-1, with the PBGD-DNA-containing plasmids was shown to produce a 2.5-2.7-fold increase in enzyme activity. Twenty-four hours after completion of the transfection procedure, transfectants were exposed for 3 h to 0.5 mM delta-ALA. Exposure of either wild type or transfectants to delta-ALA led to measurable levels of PPIX. Although this produced a modest but significant increase in intracellular PPIX content in H-MESO-1 cells compared to wild-type cells incubated with delta-ALA alone, the increase above the transfection control did not reach statistical significance. Likewise, a significant increase in PPIX was not observed in transfected MCF-7 cells subsequently exposed to delta-ALA. These data demonstrate that transient transfection of cells with the cDNA of PBGD was successful in elevating enzyme activity in both tumor cell lines, but this did not result in a comparable difference in the levels of PPIX. Such an approach for the study of other enzymes in the heme pathway should provide a model to better define rate-limiting steps in the delta-ALA induction of PPIX, and ultimately, to enhance the effectiveness of photodynamic therapy.

Delta-aminolaevulinic acid-induced photodynamic therapy inhibits protoporphyrin IX biosynthesis and reduces subsequent treatment efficacy in vitro.

Recently, considerable interest has been given to photodynamic therapy of cancer using delta-aminolaevulinic acid to induce protoporphyrin IX as the cell photosensitizer. One advantage of this modality is that protoporphyrin IX is cleared from tissue within 24 h after delta-aminolaevulinic acid administration. This could allow for multiple treatment regimens because of little concern regarding the accumulation of the photosensitizer in normal tissues. However, the haem biosynthetic pathway would have to be fully functional after the first course of therapy to allow for subsequent treatments. Photosensitization of cultured R3230AC rat mammary adenocarcinoma cells with delta-aminolaevulinic acid-induced protoporphyrin IX resulted in the inhibition of porphobilinogen deaminase, an enzyme in the haem biosynthetic pathway, and a concomitant decrease in protoporphyrin IX levels. Cultured R3230AC cells exposed to 0.5 mM delta-aminolaevulinic acid for 27 h accumulated 6.07 x 10(-16) mol of protoporphyrin IX per cell and had a porphobilinogen deaminase activity of 0.046 fmol uroporphyrin per 30 min per cell. Cells cultured under the same incubation conditions but exposed to 30 mJ cm(-2) irradiation after a 3-h incubation with delta-aminolaevulinic acid showed a significant reduction in protoporphyrin IX, 2.28 x 10(-16) mol per cell, and an 80% reduction in porphobilinogen deaminase activity to 0.0088 fmol uroporphyrin per 30 min per cell. Similar effects were evident in irradiated cells incubated with delta-aminolaevulinic acid immediately after, or following a 24 h interval, post-irradiation. There was little gain in efficacy from a second treatment regimen applied within 24 h of the initial treatment, probably a result of initial metabolic damage leading to reduced levels of protoporphyrin IX. These findings suggest that a correlation may exist between the delta-aminolaevulinic acid induction of porphobilinogen deaminase activity and the increase in intracellular protoporphyrin IX accumulation.

A regulatory role for porphobilinogen deaminase (PBGD) in delta-aminolaevulinic acid (delta-ALA)-induced photosensitization?

As an initial approach to optimize delta-aminolaevulinic acid (delta-ALA)-induced photosensitization of tumours, we examined the response of three enzymes of the haem biosynthetic pathway: delta-ALA dehydratase, porphobilinogen deaminase (PBGD) and ferrochelatase. Only PBGD activity displayed a time- and dose-related increase in tumours after intravenous administration of 300 mg kg(-1) delta-ALA. The time course for porphyrin fluorescence changes, reflecting increased production of the penultimate porphyrin, protoporphyrin IX (PPIX), showed a similar pattern to PBGD. This apparent correlation between PBGD activity and porphyrin fluorescence was also observed in four cultured tumour cell lines exposed to 0.1-2.0 mM delta-ALA in vitro. The increase in PBGD activity and PPIX fluorescence was prevented by the protein synthesis inhibitor cycloheximide. As the apparent Km for PBGD was similar before and after delta-ALA, the increase in PBGD activity was attributed to induction of enzyme de novo. These observations of an associated response of PBGD and PPIX imply that PBGD may be a rate-limiting determinant for the efficacy of delta-ALA-induced photosensitization when used in photodynamic therapy.

Time-dependent intracellular accumulation of delta-aminolevulinic acid, induction of porphyrin synthesis and subsequent phototoxicity.

Photodynamic therapy (PDT), a novel treatment for a variety of human malignancies, usually consists of visible light irradiation of lesions following the systemic administration of a photosensitizer. Induction of the endogenous photosensitizer protoporphyrin IX by the systemic or topical administration of delta-aminolevulinic acid (delta-ALA) is being investigated for use in PDT. We have determined that the incubation of two human and two rodent tumor cell lines in culture with delta-ALA over a 24 h period results in an increase in the accumulation of fluorescent porphyrins in all of these cell lines. However, the two human cell lines produce fluorescent porphyrin at different rates from those seen in the rodent cell lines. The uptake of 14C-delta-ALA was concentration dependent, similar for all the cell lines studied and rapidly reached an intra/extracellular equilibrium after delta-ALA was added to the culture medium. The increase in intracellular fluorescent porphyrin was dependent on the level of delta-ALA in the medium and the incubation time and was directly related to the phototoxicity observed upon exposure of cultured monolayers to light. The data demonstrate that equivalent levels of phototoxicity can be attained by exposing cells to 0.04 mM delta-ALA for 24 h or to 0.5 mM delta-ALA for 2 h. These findings may have implications for optimization of PDT treatment regimens that use delta-ALA.