Barriers to opioid use disorder treatment among people who use drugs in the rural United States: A qualitative, multi-site study

BACKGROUND

In 2020, 2.8 million people required substance use disorder (SUD) treatment in nonmetropolitan or 'rural' areas in the U.S. Among this population, only 10% received SUD treatment from a specialty facility, and 1 in 500 received medication for opioid use disorder (MOUD). We explored the context surrounding barriers to SUD treatment in the rural United States.

METHODS

We conducted semi-structured, in-depth interviews from 2018 to 2019 to assess barriers to SUD treatment among people who use drugs (PWUD) across seven rural U.S. study sites. Using the social-ecological model (SEM), we examined individual, interpersonal, organizational, community, and policy factors contributing to perceived barriers to SUD treatment. We employed deductive and inductive coding and analytical approaches to identify themes. We also calculated descriptive statistics for participant characteristics and salient themes.

RESULTS

Among 304 participants (55% male, mean age 36 years), we identified barriers to SUD treatment in rural areas across SEM levels. At the individual/interpersonal level, relevant themes included: fear of withdrawal, the need to "get things in order" before entering treatment, close-knit communities and limited confidentiality, networks and settings that perpetuated drug use, and stigma. Organizational-level barriers included: strict facility rules, treatment programs managed like corrections facilities, lack of gender-specific treatment programs, and concerns about jeopardizing employment. Community-level barriers included: limited availability of treatment in local rural communities, long distances and limited transportation, waitlists, and a lack of information about treatment options. Policy-level themes included insurance challenges and system-imposed barriers such as arrest and incarceration.

CONCLUSION

Our findings highlight multi-level barriers to SUD treatment in rural U.S. communities. Salient barriers included the need to travel long distances to treatment, challenges to confidentiality due to small, close-knit communities where people are highly familiar with one another, and high-threshold treatment program practices. Our findings point to the need to facilitate the elimination of treatment barriers at each level of the SEM in rural America.

Clinical Setting Comparative Analysis of Uropathogens and Antibiotic Resistance: A Retrospective Study Spanning the Coronavirus Disease 2019 Pandemic

Background

Antimicrobial resistance (AMR) in uropathogens has been increasing in Australia. Many nations observed heightened AMR during the coronavirus disease 2019 (COVID-19) pandemic, but it is not known how this may vary across clinical settings and in nations with lower infection rates.

Methods

We investigated the uropathogen composition and corresponding antibiotic resistance of 775 559 Australian isolates from the community, hospitals, and aged care facilities before (2016-2019) and during (2020-2022) the COVID-19 pandemic. A mathematical model was developed to predict the likelihood of resistance to currently recommended antibiotics for treating urinary tract infections (UTIs).

Results

Among uropathogens originating from the community, hospitals, and aged care facilities, Escherichia coli accounted for 71.4%, 57.6%, and 65.2%, respectively. During the COVID-19 pandemic period, there was an increase in UTIs caused by E coli across all settings. Uropathogens from aged care and hospitals frequently showed higher resistance to antibiotics compared to those isolated from the community. Interestingly, AMR among uropathogens showed a declining trend during the COVID-19 pandemic. Based on the resistance patterns of the past 3 years, our modeling predicted that 30%, 42.6%, and 38.8% of UTIs in the community, hospitals, and aged care facilities, respectively, would exhibit resistance to trimethoprim treatment as empirical therapy. In contrast, resistance to nitrofurantoin was predicted to be 14.6%, 26%, and 24.1% from these 3 respective settings.

Conclusions

Empirical therapy of UTIs in Australia with trimethoprim requires evaluation due to high rates of resistance observed across clinical settings.

A qualitative analysis of rural syringe service program fidelity in Appalachian Kentucky: Staff and participant perspectives

PURPOSE

As drug-related epidemics have expanded from cities to rural areas, syringe service programs (SSPs) and other harm reduction programs have been slow to follow. The recent implementation of SSPs in rural areas demands attention to program fidelity based on core components of SSP success.

METHODS

Semistructured interviews conducted with clients and staff at 5 SSPs in 5 counties within 2 Central Appalachian health districts. Interviews covered fidelity of SSP implementation to 6 core components: (1) meet needs for harm reduction supplies; (2) education and counseling for sexual, injection, and overdose risks; (3) cooperation between SSPs and local law enforcement; (4) provide other health and social services; (5) ensure low threshold access to services; and (6) promote dignity, the impact of poor fidelity on vulnerability to drug-related harms, and the risk environment's influence on program fidelity. We applied thematic methods to analyze the data.

FINDINGS

Rural SSPs were mostly faithful to the 6 core components. Deviations from core components can be attributed to certain characteristics of the local rural risk environment outlined in the risk environment model, including geographic remoteness, lack of resources and underdeveloped infrastructure, and stigma against people who inject drugs (PWID) CONCLUSIONS: As drug-related epidemics continue to expand outside cities, scaling up SSPs to serve rural PWID is essential. Future research should explore whether the risk environment features identified also influence SSP fidelity in other rural areas and develop and test strategies to strengthen core components in these vulnerable areas.

Minimally Invasive Surgical Approach for Esophageal Adenocarcinoma in a Patient with Previous Belsey Mark IV Fundoplication: A Case Report

Background: Historically, the management for recurrent or persistent Gastro-esophageal reflux disease included selective vagotomy and fundoplication. Despite these surgical interventions, the risk of Barrett’s esophagus (BE) and subsequent malignant transformation remains, requiring cancer resection surgery. We present a case of a patient with a gastro-esophageal junction (GEJ) adenocarcinoma, who underwent a pediatric thoracotomy and Belsey Mark IV fundoplication, and was successfully treated by Laparoscopic Ivor-Lewis Esophagectomy (LILE). Case Presentation: This 64-year-old gentleman with BE and GEJ adenocarcinoma was previously deemed unsuitable for curative surgery due to clinical staging indicating a tumor length of 10cm and suspected invasion of the left pleura. Further staging by Endoscopic ultrasound indicated no evidence of pleural invasion with the distal esophageal thickening in keeping with his previous Belsey Mark IV fundoplication. He underwent neo-adjuvant chemotherapy and a subsequent LILE with complete laparoscopic reversion of the gastric fundoplication without injury to the gastroepiploic artery or fundus. There was sufficient preservation of conduit length to enable a tension free hand-sewn anastomosis with an uneventful post-operative recovery. Final histopathology confirmed ypT1 ypN0 moderately differentiated adenocarcinoma with R0 resection margins. The patient has completed 24 months of cancer recurrence free surveillance. Conclusion: We describe the successful management of a patient by LILE on a background of previous hiatal fundoplication surgery, previously refused curative surgery. We highlight the importance of EUS as a staging modality for such cases showing invasive disease to increase the final clinical staging accuracy. We suggest a minimally invasive approach may be utilized for successful re-do hiatal dissection as an alternative to a conventional open surgery.

BAF facilitates interphase nuclear membrane repair through recruitment of nuclear transmembrane proteins

Nuclear membrane rupture during interphase occurs in a variety of cell contexts, both healthy and pathological. Membrane ruptures can be rapidly repaired, but these mechanisms are still unclear. Here we show barrier-to-autointegration factor (BAF), a nuclear envelope protein that shapes chromatin and recruits membrane proteins in mitosis, also facilitates nuclear membrane repair in interphase, in part through recruitment of the nuclear membrane proteins emerin and Lem-domain-containing protein 2 (LEMD2) to rupture sites. Characterization of GFP-BAF accumulation at nuclear membrane rupture sites confirmed BAF is a fast, accurate, and persistent mark of nucleus rupture whose kinetics are partially dictated by membrane resealing. BAF depletion significantly delayed nuclear membrane repair, with a larger effect on longer ruptures. This phenotype could be rescued by GFP-BAF, but not by a BAF mutant lacking the Lap2, emerin, Man1 (LEM)-protein binding domain. Depletion of the BAF interactors LEMD2 or emerin, and to a lesser extent lamin A/C, increased the duration of nucleus ruptures, consistent with LEM-protein binding being a key function of BAF during membrane repair. Overall our results suggest a model where BAF is critical for timely repair of large ruptures in the nuclear membrane, potentially by facilitating membrane attachment to the rupture site.

The effect of NaOCl and heat treatment on static and dynamic mechanical properties and chemical changes of dentine

OBJECTIVES

To determine the effect of heat on flexural strength (FS), maximum strain (MS), storage modulus (SM), tan delta (TD) and chemical changes through micro-Raman spectroscopy of dentine exposed to 2.5% NaOCl or saline.

METHOD

ology: Dentine bars were randomly allocated to 8 test groups. Half (groups 2,4,6,8) were treated with NaOCl for 20 min; the rest (groups 1,3,5,7) remained in saline. FS/MS were measured in groups 1-4 (n = 15) (3/4 were also heated to 200 °C & re-hydrated in saline). Micro-Raman spectroscopy was performed on bars from groups 1-4. SM/TD were measured in 5-8: in 5/6 (n = 10), repeated after heating (200 °C), then following re-hydration; in 7/8 (n = 3) after heating to 25-185 °C.

RESULTS

Increase in MS on heat and FS/MS on heat + NaOCl was not significant (P > 0.05). SM increased (P = 0.06) after heat treatment but reduced to initial state after rehydration (P = 0.03). TD did not change (P = 0.4) after heat (200 °C) treatment but rehydration increased it compared with pre-treatment state (P = 0.001). For dentine bars pre-treated with NaOCl, SM did not change (P = 0.6) after heat (200 °C) treatment or rehydration but TD significantly increased (P = 0.02) upon re-hydration compared with pre- (P=0.007), or post- (P = 0.03) heat-treatment states. SM and TD varied between 25-185 °C with no consistent trend amongst the NaOCl pre-treated bars. Micro-Raman only detected chemical changes following NaOCl treatment in the mineral phase.

CONCLUSIONS

Exposure of dentine bars to heat and NaOCl produced only moderate changes to quasi-static but marked changes to viscoelastic properties, which may be explained by chemical alterations.

Anatomy of STEM teaching in North American universities

National and local initiatives focused on the transformation of STEM teaching in higher education have multiplied over the last decade. These initiatives often focus on measuring change in instructional practices, but it is difficult to monitor such change without a national picture of STEM educational practices, especially as characterized by common observational instruments. We characterized a snapshot of this landscape by conducting the first large scale observation-based study. We found that lecturing was prominent throughout the undergraduate STEM curriculum, even in classrooms with infrastructure designed to support active learning, indicating that further work is required to reform STEM education. Additionally, we established that STEM faculty’s instructional practices can vary substantially within a course, invalidating the commonly-used teaching evaluations based on a one-time observation.

Although lecture is prominent throughout the undergraduate STEM curriculum, STEM faculty employ varied teaching practices within the same course.

Optimized Fluorescence Complementation Platform for Visualizing Salmonella Effector Proteins Reveals Distinctly Different Intracellular Niches in Different Cell Types

The bacterial pathogen Salmonella uses sophisticated type III secretion systems (T3SS) to translocate and deliver bacterial effector proteins into host cells to establish infection. Monitoring these important virulence determinants in the context of live infections is a key step in defining the dynamic interface between the host and pathogen. Here, we provide a modular labeling platform based on fluorescence complementation with split-GFP that permits facile tagging of new Salmonella effector proteins. We demonstrate enhancement of split-GFP complementation signals by manipulating the promoter or by multimerizing the fluorescent tag and visualize three effector proteins, SseF, SseG, and SlrP, that have never before been visualized over time during infection of live cells. Using this platform, we developed a methodology for visualizing effector proteins in primary macrophage cells for the first time and reveal distinct differences in the effector-defined intracellular niche between primary macrophage and commonly used HeLa and RAW cell lines.

Methods to Illuminate the Role of Salmonella Effector Proteins during Infection: A Review

Intracellular bacterial pathogens like Salmonella enterica use secretion systems, such as the Type III Secretion System, to deliver virulence factors into host cells in order to invade and colonize these cells. Salmonella virulence factors include a suite of effector proteins that remodel the host cell to facilitate bacterial internalization, replication, and evasion of host immune surveillance. A number of diverse and innovative approaches have been used to identify and characterize the role of effector proteins during infection. Recent techniques for studying infection using single cell and animal models have illuminated the contribution of individual effector proteins in infection. This review will highlight the techniques applied to study Salmonella effector proteins during infection. It will describe how different approaches have revealed mechanistic details for effectors in manipulating host cellular processes including: the dynamics of effector translocation into host cells, cytoskeleton reorganization, membrane trafficking, gene regulation, and autophagy.

Long-term live-cell imaging reveals new roles for Salmonella effector proteins SseG and SteA

Salmonella Typhimurium is an intracellular bacterial pathogen that infects both epithelial cells and macrophages. Salmonella effector proteins, which are translocated into the host cell and manipulate host cell components, control the ability to replicate and/or survive in host cells. Due to the complexity and heterogeneity of Salmonella infections, there is growing recognition of the need for single-cell and live-cell imaging approaches to identify and characterize the diversity of cellular phenotypes and how they evolve over time. Here, we establish a pipeline for long-term (17 h) live-cell imaging of infected cells and subsequent image analysis methods. We apply this pipeline to track bacterial replication within the Salmonella-containing vacuole in epithelial cells, quantify vacuolar replication versus survival in macrophages and investigate the role of individual effector proteins in mediating these parameters. This approach revealed that dispersed bacteria can coalesce at later stages of infection, that the effector protein SseG influences the propensity for cytosolic hyper-replication in epithelial cells, and that while SteA only has a subtle effect on vacuolar replication in epithelial cells, it has a profound impact on infection parameters in immunocompetent macrophages, suggesting differential roles for effector proteins in different infection models.

From Hospital to Home: Limited Nutritional and Functional Recovery for Older Adults

BACKGROUND

The post-hospital period may be a vulnerable time for elders recovering from acute illness. Few studies have examined nutrition outcomes of older people at nutrition risk after acute hospitalisation.

OBJECTIVES

This study aims to describe a) standard nutrition care received by recently discharged older medical patients, b) change in nutritional and functional status at six weeks post-discharge and c) clinical outcomes at twelve weeks post discharge.

DESIGN

Prospective cohort study.

SETTING

Two metropolitan teaching hospitals in Brisbane, Australia.

PARTICIPANTS

Medical patients aged ≥65 years at risk of malnutrition (Malnutrition Screening Score ≥2) and discharged to independent living in the community.

MEASUREMENT

Nutritional status (Mini Nutritional Assessment (MNA), weight, lean body mass), functional status (grip strength, walk speed, activities of daily living) and health-related quality of life assessed on discharge and six weeks post-discharge. Inpatient and post-discharge nutrition intervention was recorded. Death and unplanned admissions were measured at 12 weeks.

RESULTS

Of the 42 consented participants, only 14% (n=6) received post-discharge dietitian review and 19% (n=8) received practical nutrition supports at home (meal delivery, shopping assistance) as part of standard care. While there was a small improvement in MNA (18.4±4.0 to 20.1±4.2, p=0.004) and walk speed (0.7±0.3 m/s to 0.9±0.3, p=0.004) at six weeks, there was no difference in mean weight, lean body mass, grip strength or activities of daily living. Five (15%) participants lost ≥5% body weight. By twelve weeks, 17 participants (46%) had at least one unplanned hospital admission and four (10%) had died.

CONCLUSIONS

Few patients at nutrition risk received nutrition-focussed care in the post-hospital period, and most did not improve nutritional or functional status at 6 weeks.

Conversion, shrinkage, water sorption, flexural strength and modulus of re-mineralizing dental composites

OBJECTIVES

Cure, volumetric changes and mechanical properties were assessed for new dental composites containing chlorhexidine (CHX) and reactive calcium phosphate-containing (CaP) to reduce recurrent caries.

METHODS

20wt.% of light curable urethane dimethacrylate based liquid was mixed with 80wt.% glass filler containing 10wt.% CHX and 0-40wt.% CaP. Conversion versus depth with 20 or 40s light exposure was assessed by FTIR. Solidification depth and polymerization shrinkage were determined using ISO 4049 and 17304, respectively. Subsequent volume expansion and biaxial flexural strength and modulus change upon water immersion were determined over 4 weeks. Hydroxyapatite precipitation in simulated body fluid was assessed at 1 week.

RESULTS

Conversion decreased linearly with both depth and CaP content. Average solidification depths were 4.5, 3.9, 3.3, 2.9 and 5.0 with 0, 10, 20, and 40% CaP and a commercial composite, Z250, respectively. Conversions at these depths were 53±2% for experimental materials but with Z250 only 32%. With Z250 more than 50% conversion was achieved only below 1.1mm. Shrinkage was 3% and 2.5% for experimental materials and Z250, respectively. Early water sorption increased linearly, whilst strength and modulus decreased exponentially to final values when plotted versus square root of time. Maximum volumetric expansion increased linearly with CaP rise and balanced shrinkage at 10-20wt.% CaP. Strength and modulus for Z250 decreased from 191 to 158MPa and 3.2 to 2.5GPa. Experimental composites initial strength and modulus decreased linearly from 169 to 139MPa and 5.8 to 3.8GPa with increasing CaP. Extrapolated final values decreased from 156 to 84MPa and 4.1 to 1.7GPa. All materials containing CaP promoted hydroxyapatite precipitation.

SIGNIFICANCE

The lower surface of composite restorations should both be solid and have greater than 50% conversion. The results, therefore, suggest the experimental composite may be placed in much thicker layers than Z250 and have reduced unbounded cytotoxic monomer. Experimental materials with 10-20wt.% additionally have volumetric expansion to compensate shrinkage, antibacterial and re-mineralizing components and competitive mechanical properties.

Function of glandular secretions in fragrance collection by male euglossine bees (Apidae: Euglossini)

MaleEulaema cingulata (Fabricius) (Apidae: Euglossini) possess large cephalic labial glands that secrete a mixture of lipids. In the process of fragrance collection, males secrete the labial gland lipids onto the substrate. The mixture of lipids and fragrances is then taken up by the front tarsal brushes and transferred to the hind tibial organs. The labial gland secretions apparently serve as a nonpolar solvent and carrier that increases the efficiency of fragrance collection.

Prevalence and correlates of recent vaginal douching among African American adolescent females

STUDY OBJECTIVE

To describe the prevalence and correlates of vaginal douching among urban African American adolescents and to examine the association between douching and sexually transmitted infection (STI) status.

DESIGN

Demographic, psychosocial, and behavioral data were collected through cross-sectional, self-administered surveys. Self-collected vaginal swabs were assayed using nucleic acid amplification tests for trichomoniasis, chlamydia, and gonorrhea.

SETTING

Sexual health clinic in a large metropolitan area of the southeastern United States.

PARTICIPANTS

African American females (N = 701), ages 14-20, participating in a human immunodeficiency virus prevention intervention.

MAIN OUTCOME MEASURE

The outcome of interest was the association between vaginal douching (lifetime, past 90 days, and past 7 days) with demographic characteristics (eg, age, education, and socioeconomic status), physical and mental health status, STI status, sexual behavior (eg, number of vaginal sexual partners, age of sex partners, consistent condom use in the past 90 days, sex while self/partner was high on drugs or alcohol), and psychosocial characteristics (eg, sexual adventurism, social support, peer norms, sexual satisfaction, self-efficacy for sex refusal, self-esteem, relationship power, risk avoidance).

RESULTS

Forty-three percent reported ever douching, and 29% reported douching in the past 90 days. In bivariate analyses, recent douching was associated with demographic, behavioral, and psychosocial variables, but not current STI status. In multivariate analyses, recent douching was associated with age (odds ratio [AOR] = 1.13, confidence interval [CI] = 1.02-1.25), lower socioeconomic status (AOR = 1.25, CI = 1.05-1.47), and having sex with much older partners (AOR = 1.87, CI = 1.22-2.86).

CONCLUSION

Increased age, lower socioeconomic status, and older partners may be salient risk factors for douching behavior among African American young women.

Electrical performances and structural designs of copper bonding in wafer-level three-dimensional integration

The integrity of bonded Cu interconnects in wafer-level three-dimensional integration has been investigated as the function of pattern size and density, as well as bonding process parameter. The desired pattern density coupled with the application of bonding process profile we developed gives optimal yield and alignment accuracy, and provides excellent electrical connectivity and contact resistance through the entire wafer. This result is a key milestone in establishing the manufacturability of Cu-based interconnections for 3D integration technology.

Oncolytic adenoviral gene therapy in ovarian cancer: why we are not wasting our time

Preclinical gene-therapy studies in the past 15 years have repeatedly raised hopes that we were about to enter a brave new era. However, many clinical trials have disappointed. For tumor types with poor response rates to first-line conventional cytotoxic chemotherapy and/or high rates of chemorefractory disease, there remain very few treatment options. In this article we review gene therapy within the context of ovarian cancer. We examine why clinical data have been discouraging and discuss how the lessons learned from earlier trials are being applied to current research.

Dense collagen matrix accelerates osteogenic differentiation and rescues the apoptotic response to MMP inhibition

Bone is distinguished from other tissues by its mechanical properties, in particular stiffness. However, we know little of how osteoblasts react to the stiffness of their microenvironment; in this study we describe their response to a dense (>10 wt.%) collagenous 3D environment. Primary pre-osteoblasts were seeded within a novel form of native collagen, dense collagen, and cultured for up to 14 days in the presence and absence of osteogenic supplements: analysis was via Q-PCR, histology, fluorescent in situ zymography, MMP loss-of-function and tensile testing. Differentiation as measured through the up-regulation of Bsp (247-fold), Alp (14.2-fold), Col1A1 (4.5-fold), Mmp-13 (8.0-fold) and Runx2 (1.2-fold) transcripts was greatly accelerated compared to 2D plastic at 7 and 14 days in the same medium. The scale of this enhancement was confirmed through the use of growth factor stimulation on 2D via the addition of BMP-6 and the Hedgehog agonist purmorphamine. In concert, these molecules were capable of the same level of osteo-induction (measured by Bsp and Alp expression) as the dense collagen alone. Mineralisation was initially localised to remodelled pericellular regions, but by 14 days embedded cells were discernible within regions of apatite (confirmed by MicroRaman). Tensile testing of the matrices showed that this had resulted in a significant increase in Young's modulus at low strain values, consistent with a stiffening of the matrix. To determine the need for matrix remodelling in the mineralisation event the broad spectrum MMP Inhibitor Ilomastat was used. It was found that in its presence mineralisation could still occur (though serum-specific) and the apoptosis associated with MMP inhibition in hydrated collagen gels was abrogated. Analysis of gene expression indicated that this was due to the up-regulation of Mmp-13 in the presence of Ilomastat in dense collagen (400-fold), demonstrating a powerful feedback loop and a potential mechanism for the rescue from apoptosis. Osteoid-like matrix (dense collagen) is therefore a potent stimulant of osteoblast differentiation in vitro and provides an environment that enables survival and differentiation in the presence of MMP inhibition.

Application of mobile phone technology for managing chemotherapy-associated side-effects

BACKGROUND

Novel mobile phone technology linked to a server that communicates patients' symptoms to healthcare professionals has been adapted to register the side- effects of chemotherapy and provide advice on management of toxicity. We report a feasibility study to examine the utility of home monitoring of patients' symptoms via a mobile phone.

METHODS

Six colon cancer patients receiving adjuvant chemotherapy, entered symptom data onto user friendly screens on a mobile phone twice daily. This 'real time' self assessment of nausea, vomiting, mucositis, diarrhoea and hand-foot syndrome and measurement of temperature was sent via a secured connection to a remote computer. In the event of moderate or severe symptoms (generating amber and red alerts respectively), the nurse was immediately alerted by the computer, via a pager. The nurse then contacted the patient to reinforce the automatic advice sent to the patient on their phone and to assess the patient using clinical algorithms.

RESULTS

The patient used the mobile phones during the first two cycles of chemotherapy. The data were successfully analysed by the server software and alerts were generated alerting the study nurses to patients' symptoms at the appropriate time. There were 91 alerts-54 red and 37 amber; 54% (29/54) of the red alerts were data delay and transmission problems which were swiftly rectified. The remaining red alerts were managed appropriately by the study nurses. Both patients and staff felt confident in this approach to symptom management.

CONCLUSIONS

This study demonstrates that the technology for monitoring patients' symptoms worked well. The patients felt secure in the knowledge that their symptoms were being closely monitored and that they were participating effectively in their own care management.

Immune Reconstitution Inflammatory Syndrome Associated With Kaposi's Sarcoma

Purpose

A proportion of patients with HIV infection who subsequently receive highly active antiretroviral therapy (HAART) exhibit a deterioration in their clinical status, despite control of virologic and immunologic parameters. This clinical response, known as the immune reconstitution inflammatory syndrome (IRIS), occurs secondary to an immune response against previously diagnosed pathogens.

Patients and Methods

From our cohort of 5,832 patients treated in the HAART era, we identified 150 therapy-naive patients with a first presentation of Kaposi's sarcoma (KS). Their clinicopathologic features and progress were recorded prospectively.

Results

After commencing HAART, ten patients (6.6%) developed progressive KS, which we identify as IRIS-associated KS. In a comparison of these individuals with those whose KS did not progress, we found that IRIS-KS occurred in patients with higher CD4 counts (P = .03), KS-associated edema (P = .01), and therapy with both protease inhibitors and non-nucleosides together (P = .03). Time to treatment failure was similar for both groups, although the CD4 count declined more rapidly at first, in those patients with IRIS-associated KS. Despite this initial decline, in our clinical experience HAART could be successfully continued in those with IRIS-associated KS.

Conclusion

We have identified IRIS-KS in a cohort of HIV patients with KS who start HAART.

FTIR investigation of monomer polymerisation and polyacid neutralisation kinetics and mechanisms in various aesthetic dental restorative materials

Diamond ATR FTIR has been used to quantify light catalysed polymerisation and polyacid neutralisation rates in various glass ionomer cements (GIC), resin-modified GICs (RMGIC) and compomers. At 150s after the start of light exposure, levels of methacrylate polymerisation on the lower surfaces of 1mm thick specimens were 97% and 98% for the RMGIC, Vitremer and Fuji II LC and 47% and 37% for the compomers, Compoglass and Dyract. After light exposure, polymerisation rates for the compomers decreased linearly with inverse time. By 50,000s Compoglass and Dyract were 62% and 51% polymerised. Initial rate of polyacid neutralisation in the GIC Shofu HIFI was 0.32 times that of Fuji IX GIC. Those in Vitremer, Fuji II LC, Compoglass and Dyract were 0.16, 0.09, 0.004 and 0.004 times that of Fuji IX. Excluding short initial periods, log of neutralisation rates decreased linearly with log-time. Average gradients were -1.35 for the GIC, -0.80 for the RMGIC and -0.59 for the compomers. By 50,000s, polyacid salt concentrations for the RMGIC and compomers were 0.41 and 0.016 times that of the GIC. Reaction mechanisms have been discussed and used to help interpret material mechanical properties, fluoride release rates and adhesion to tooth structure.

FTIR investigation of polymerisation and polyacid neutralisation kinetics in resin-modified glass-ionomer dental cements

A new diamond ATR FTIR method has been developed to quantify the processes occurring in the resin-modified glass-ionomer cement (RMGIC). Fuji II LC (Improved), at 1 mm depth from the cement/water interface. With Fuji II LC (Improved) various changes in the spectra due to 90% monomer polymerisation were observed within 1 min after 20 s exposure to a dental light. Following polymerisation further different peak shifts with time were detected. Comparison with spectral changes seen during setting of the conventional glass-ionomer cement, Fuji IX, showed these could be assigned to water sorption and/or polyacid neutralisation. Any absorbance change due to the acid/glass reaction alone exhibited 2 linear regions when plotted against square root of time. Such behaviour suggests two separate diffusion mechanisms for acid neutralisation. The first faster one ceases at 30 or 150 min after mixing in Fuji IX and Fuji II LC (Improved), respectively. It was proposed that these were the times at which all the water (a required component of the reaction) in the original formulation is used up. The slower process was the same acid/glass reaction but initiated by water sorption. The initial rates of absorbance change due to acid neutralisation were 17 times faster for Fuji IX than Fuji II LC (Improved). By 4 days however, the total absorbance change due to acid neutralisation for Fuji IX was only 4 times that for Fuji II LC (Improved). Such results can help to explain changes in cement properties with time.

Prospective randomized comparison of dacarbazine (DTIC) versus DTIC plus interferon-alpha (IFN-alpha) in metastatic melanoma

Dacarbazine (DTIC) has been the mainstay of chemotherapy for metastatic melanoma for over two decades, but only 15%-20% of patients respond and benefit is usually transient. Randomized studies combining DTIC with interferon-alpha (IFN-alpha) in advanced disease have so far been inconclusive in terms of response and survival. We report a randomized prospective pilot Phase III trial of DTIC +IFN-alpha in patients with metastatic melanoma. The primary endpoint was death. A total of 61 patients were randomized between April 1995 and April 1998. Differences in survival between groups were assessed using log-rank analysis. Quality of life was measured using the European Organization for Research on Treatment of Cancer QLQ C30 (+3) questionnaire. Fifty-seven patients died during the study. The median survival for patients receiving DTIC was 7.2 months (95% confidence interval (CI) 4.4-9.0); it was 4.8 months for DTIC + IFN-alpha (95% CI 2.0-8.0). There was no significant difference in survival between the two treatment arms (chi2 unadjusted = 0.15, P = 0.70; chi2 adjusted = 0.01, P = 0.91). The 6-month survival of those patients randomized to DTIC alone was 58% compared with 40% for those patients randomized to DTIC + IFN-alpha. There were no differences in quality of life between treatment groups. This study failed to demonstrate a survival benefit for patients receiving IFN-alpha in combination with DTIC. These results are inconclusive primarily owing to the small size of the trial. A meta-analysis is required to determine whether there is a role for the addition of IFN-alpha to DTIC in the treatment of this disease.

Dealing with daily hassles: smoking and African-American adolescent girls

PURPOSE

To examine cigarette use and its relationship to daily life hassles in an urban sample of African-American adolescent girls.

METHODS

A sample of 105 African-American adolescent girls (mean age of 15.45 years) derived from a larger cross-sectional research project titled "Female Adolescent Substance Experience Study" funded by the National Institute of Drug Abuse comprised the sample. The sample was divided into adolescents who had ever smoked in their lifetime and adolescents who had never smoked before. Student's t-tests were conducted to determine whether there were differences between these groups on demographic characteristics and the number of daily life hassles. Pearson product moment correlations were also conducted to examine the association between age of smoking initiation and number of hassles.

RESULTS

Less than 50% of the teenagers had ever smoked cigarettes in their lifetime, and of those who had ever smoked, the average age of initiation was 12.55 years (SD = 2.63). Furthermore, girls who had ever smoked, in contrast to girls who had never smoked, had a significantly greater number of daily life hassles, in general, and within the school/academic and family/economic domains in particular. Age of smoking initiation was negatively related to the number of hassles, indicating that girls who started to smoke at a younger age reported more hassles.

CONCLUSIONS

These findings are discussed in terms of developing an understanding of gender and ethnic-specific correlates of smoking that can be used to better delineate the developmental smoking trajectory of African-American girls.

Social Isolation & Sexual Abuse Among Women Who Smoke Crack

The purpose of this study was to explore the prevalence of social isolation and its relationship to sexual trauma in a sample of Black women who smoke crack cocaine. Using a convenience sample of 115 Black women with a history of smoking crack cocaine, participants were interviewed for 2 to 4 hours and asked a variety of questions about their health, relationships, sexuality, and drug use. Bivariate and multivariate logistical regressions were used to predict whether the women reported being socially isolated. While social isolation was not necessarily a common experience among the sample, it was found that women who had been sexually abused were three times more likely to report being socially isolated than women who had not been sexually abused. In addition, social isolation was more common among women who had been abused by a family member, who had been abused when they were young, and who had been abused for a long period of time. However, multivariate analyses revealed that the age at which the sexual trauma occurred was the most salient predictor of social isolation in adulthood. Implications for drug treatment are discussed.

Presynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor-mediated stimulation of glutamate and GABA release in the rat striatum in vivo: a dual-label microdialysis study

The existence of presynaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-type glutamate autoreceptors on glutamate nerve terminals in vitro has recently been demonstrated using synaptosomal and brain slice preparations. In the present study we have used a modification of a rapid dual-label intracerebral microdialysis method, previously developed by Young and co-workers(80,81) for the study of presynaptic mechanisms of neurotransmitter release, to investigate whether presynaptic AMPA receptors also play a role in the control of striatal glutamate release in vivo. For comparative purposes, the action of locally applied AMPA on striatal GABA release in vivo was also monitored. Local application of AMPA (0.01-100 microM), by reverse dialysis, into the striatum resulted in concentration-dependent increases in the Ca(2+)-dependent efflux of both [3H]L-glutamate and [14C]GABA. Maximum responses reached 142.0+/-6.5% and 166.8+/-7.7% of basal efflux for [3H]L-glutamate and [14C]GABA, respectively. No marked behavioural changes were observed at any dose of the agonist. Unexpectedly, the AMPA-evoked responses were not potentiated by the AMPA receptor desensitization inhibitors cyclothiazide (10-100microM) or aniracetam (1mM). Consistent with this finding, AMPA-stimulated [3H]L-glutamate and [14C]GABA efflux were significantly attenuated by co-perfusion with the selective, competitive AMPA receptor antagonist 6-nitro-7-sulphamoylbenzo(F)quinoxaline-2,3-dione (100microM) but not 1-(aminophenyl)-4-methyl-7,8-methylendioxy-5H-2,3-benzodiazepine (100microM), a non-competitive AMPA receptor antagonist known to interact with the cyclothiazide site to control AMPA receptor function. The broad spectrum ionotropic glutamate receptor antagonist, kynurenic acid (100-1000microM) also markedly inhibited the AMPA-evoked responses in the striatum in vivo. None of the antagonists, when given alone, influenced basal efflux of [3H]L-glutamate suggesting a lack of tonic regulatory control of glutamate release via presynaptic AMPA-type autoreceptors in the rat striatum. These results demonstrate the presence of presynaptic AMPA receptors, of a novel cyclothiazide- and aniracetam-insensitive subtype, on presynaptic nerve terminals in the rat striatum in vivo, acting to enhance glutamate and GABA release. Our data support the concept of AMPA receptor heterogeneity in vivo, a finding which may facilitate the development of novel, more selective drugs for the treatment of a range of neurological disorders associated with abnormal cerebral glutamate release. The pharmacological profile of these novel presynaptic receptors is currently under investigation.

Access conditions are crucial: comment on Lynch and Carroll (2001)

W. J. Lynch and M. E. Carroll (2001) sought to identify factors that control drug intake, that is, factors that decrease the avidity of drug seeking and drug taking while drug is obviously available. The review provides updated information about factors that regulate drug intake and a heuristic framework for future studies of regulatory processes throughout the natural history of a substance abuse disorder. In particular, the review suggests a productive framework for studies of transitions from early drug use to later abusive use. Forceful identification of factors that control the avidity of drug seeking and drug taking under the controlled conditions of the laboratory may encourage development of therapeutic interventions that capitalize on these factors for successful treatment of human drug abuse. Extending the analysis of regulation of intake to include factors that can be manipulated to reorganize behavior may improve the design of interventions to treat drug abuse.

Effect of radiographic quality on computer-assisted head penetration measurements

Even the most sophisticated computer-assisted radiographic techniques of measuring femoral head penetration into the polyethylene liner depend on the quality of the radiograph being evaluated, which varies greatly in clinical settings. The authors of this study sought to determine how the accuracy and reproducibility of three commercially available computer-assisted measurement systems differed when measuring optimal radiographs (with sharply defined component edges) and suboptimal radiographs (with less well defined edges). Using three computer-assisted measurement systems, the authors measured head penetration on simulated and clinical hip radiographs. All systems calculated head penetration as the movement of the head center relative to the cup center. To define the periphery of the prosthetic head and cup, one method (System One) used the human eye and a digitizing tablet, whereas the other two methods (System Two and System Three) used digital edge detection algorithms. For simulated hip radiographs, error was calculated as the absolute value of the difference between the known amount of head penetration, determined by a coordinate measuring machine, and the amount of penetration determined by the software. Three way analysis of variance showed a significant difference in absolute error among the three measurement techniques. System One had a significantly smaller absolute error (0.11 +/- 0.06 mm) than did System Two (0.25 +/- 0.25 mm) and System Three (0.19 +/- 0.13 mm). In addition, three-way analysis of variance showed that optimal radiographs were associated with a significantly lower absolute error (0.14 +/- 0.09 mm) than were suboptimal radiographs (0.23 +/- 0.22 mm). For optimal radiographs, there was no significant difference in error among the three measurement methods; all systems were accurate and reproducible. However, for suboptimal radiographs absolute error increased and varied widely, and a significant difference among the methods existed. These data show the susceptibility of head penetration measurements to radiographic technique and underscore the importance of good quality radiographs for all analyses of head penetration.

Modulation of latent inhibition in the rat by altered dopamine transmission in the nucleus accumbens at the time of conditioning

Latent inhibition describes a process by which pre-exposure of a stimulus without consequence retards the learning of subsequent conditioned associations with that stimulus. It is well established that latent inhibition in rats is impaired by increased dopamine function and potentiated by reduced dopamine function. Previous evidence has suggested that these effects are modulated via the meso-accumbens dopamine projections. We have now undertaken three experiments to examine this issue directly, especially in the light of one study in which latent inhibition was reported to be unaffected by direct injection of amphetamine into the accumbens. Latent inhibition was studied using the effect of pre-exposure of a tone stimulus on the subsequent formation of a conditioned emotional response to the tone. 6-Hydroxydopamine-induced lesions of dopamine terminals in the nucleus accumbens resulted in potentiation of latent inhibition. Bilateral local injections of the dopamine antagonist haloperidol into the nucleus accumbens (0.5 microg/side) before conditioning also potentiated latent inhibition. Moreover, such injections were able to reverse the disruptive effect of systemic amphetamine (1mg/kg, i.p.) on latent inhibition. Bilateral local injection of amphetamine (5 microg/side) into the nucleus accumbens before conditioning was able to disrupt latent inhibition, provided that it was preceded by a systemic injection of amphetamine (1mg/kg) 24h earlier.We conclude that the attenuation of latent inhibition by increased dopamine function in the nucleus accumbens is brought about by impulse-dependent release of the neurotransmitter occurring at the time of conditioning. The previously reported failure to disrupt latent inhibition with intra-accumbens amphetamine is probably due to impulse-independent release of dopamine. The implications of these conclusions for theories linking disrupted latent inhibition to the attentional deficits in schizophrenia, and to the dopamine theory of this disorder, are discussed.

Reflections on validity and epistemology in a study of working relations between deaf and hearing professionals

In this article, a research study that examined the working relationships between Deaf and hearing professionals in health and educational services in the United Kingdom is addressed. These service providers worked in bilingual organizations where both British Sign Language and English were used and in which Deaf people's identity as a cultural-linguistic minority was accepted. The focus of this article is on issues of validity and epistemology that arose for the Deaf and hearing research team in the course of this study. In particular, it examines the influence of identity attributions on the research process for researchers operating within a context of historical oppression, minority language use and legitimization of research knowledge, and challenges to the interpretative analysis used in the study that arose from the dynamics of majority-minority power relations in the wider social world.

Differential tolerance to antinociceptive effects of mu opioids during repeated treatment with etonitazene, morphine, or buprenorphine in rats

RATIONALE

Repeated treatment experiments with high and low efficacy agonists provide critical insight into possible mechanisms underlying development of opioid tolerance.

OBJECTIVE

Experiments in a tail-withdrawal assay tested the hypothesis that magnitude of tolerance to antinociceptive effects is inversely related to agonist relative efficacy in rats intermittently treated with etonitazene. morphine, or buprenorphine.

METHODS

The antinociceptive effects of five mu opioid agonists were tested in male, Sprague-Dawley rats in a warm-water tail-withdrawal assay. To induce tolerance, escalating doses of the higher efficacy agonist etonitazene, the high efficacy agonist morphine, or the lower efficacy agonist buprenorphine were administered twice daily for 2-8 weeks.

RESULTS

Etonitazene, etorphine, morphine, buprenorphine, and GPA 1657 [(1)-beta-2'-hydroxy-2,9-dimethyl-5-phenyl-6,7-benzomorphan] produced dose-dependent increases in tail-withdrawal latency until 100% maximum possible effect (%MPE) was obtained. Treatment with escalating doses of etonitazene, morphine, or buprenorphine produced greater tolerance to the lower efficacy agonists buprenorphine and GPA 1657 than to the higher efficacy agonists etonitazene, etorphine, and morphine. Treatment with buprenorphine, a lower efficacy agonist, produced greater tolerance than did treatment with equivalent doses of the higher efficacy agonists morphine or etonitazene.

CONCLUSIONS

Taken together, these data suggest that magnitude of antinociceptive tolerance is inversely related to relative efficacy of mu agonists, with lower efficacy agonists being more susceptible to tolerance than are higher efficacy agonists under these intermittent dosing conditions.

Pre-clinical and clinical study of QC12, a water-soluble, pro-drug of quercetin

BACKGROUND

Quercetin is a naturally occurring flavonoid with many biological activities including inhibition of a number of tyrosine kinases. A phase I, dose-escalation trial of quercetin defined the maximum tolerated dose (MTD) as 1700 mg/m2 three weekly, but the vehicle, dimethyl sulphoxide (DMSO) is unsuitable for further clinical development of quercetin.

PATIENTS AND METHODS

A water-soluble, pro-drug of quercetin (3'(N-carboxymethyl)carbomyl-3,4',5,7-tetrahydroxyflavone), QC12 has been synthesised. Six cancer patients received 400 mg of QC12 (equivalent to 298 mg of quercetin), orally on day 1 and intravenously (i.v.) in normal saline on day 14.

RESULTS

Following oral administration of QC12 we were unable to detect QC12 or quercetin in plasma. After i.v. administration, we detected peak plasma concentrations of QC12 of 108.7 +/- 41.67 microMolar (microM). A two-compartment model with mean t(1/2)alpha of 0.31 +/- 0.27 hours and mean t(1/2)beta of 0.86 +/- 0.78 hours best described the concentration-time curves for QC12. The mean AUC was 44.54 +/- 13.0 microM.hour and mean volume of distribution (Vd) of 10.0 +/- 6.2 litres (l). Quercetin was found in all patients following i.v. infusion of QC12, with peak levels of quercetin 19.9 +/- 11.8 microM. The relative bioavailability of quercetin was estimated to be 20%-25% quercetin released from QC12.

CONCLUSIONS

QC12 is not orally bioavailable. This water-soluble pro-drug warrants further clinical investigation; starting with a formal phase I, IV, dose-escalation study.

Use of Raman spectroscopy in the characterisation of the acid-base reaction in glass-ionomer cements

Raman spectra of various combinations of glass-ionomer cement components have been compared with those of the reactants and the salts of polyacrylic and tartaric acids. The components consisted of a fast-setting acid-degradable dental glass (containing, inter alia, oxides of Si, Al, Ca, Ba and Na), polyacrylic acid (PAA) and/or tartaric acid (TA). On the addition of water to the glass and tartaric acid, Raman spectroscopy indicated loss of acid and production of tartrate salts within seconds of mixing. Mixtures containing the glass, PAA and water in mass ratios 2:1:(0.1-4) reacted to form polyacrylate salts. The maximum fraction of unreacted PAA was found to decrease linearly with initial water/PAA mass ratio to a minimum of approximately 20% when this ratio exceeds 1.5. The data are consistent with 5.6 moles of water being required when each mole of acidic groups is neutralised. In newly prepared cements containing glass, water, polyacrylic and tartaric acids, polyacrylic acid and its salts, in both ionised and solid state form, can be detected. After about 1 h, however, Raman peaks associated with ionised species disappear.

Comparison of in vivo wear between polyethylene liners articulating with ceramic and cobalt-chrome femoral heads

At yearly intervals we compared the radiological wear characteristics of 81 alumina ceramic femoral heads with a well-matched group of 43 cobalt-chrome femoral heads. Using a computer-assisted measurement system we assessed two-dimensional penetration of the head into the polyethylene liner. We used linear regression analysis of temporal data of the penetration of the head to calculate the true rates of polyethylene wear for both groups. At a mean of seven years the true rate of wear of the ceramic group was slightly greater (0.09 mm/year, SD 0.07) than that of the cobalt-chrome group (0.07 mm/year, SD 0.04). Despite the numerous theoretical advantages of ceramic over cobalt-chrome femoral heads, the wear performance in vivo of these components was similar.

A phase II study of the 5-lipoxygenase inhibitor, CV6504, in advanced pancreatic cancer: correlation of clinical data with pharmacokinetic and pharmacodynamic endpoints

PURPOSE

Primary objective was to determine response rate of patients with advanced pancreatic cancer to a novel lipoxygenase and thromboxane A2 synthetase inhibitor (CV6504); secondary objectives included estimation of pharmacokinetics of CV6504, target-enzyme inhibition, safety and tolerance, quality of life and survival.

PATIENTS AND METHODS

Thirty-one patients with advanced pancreatic cancer were planned to receive CV6504, 100 mg TDS, orally for three months, at which point CT scans were performed to assess therapeutic response rates. Steady state concentrations of CV6504 and thromboxane B2 (an indirect measure of thromboxane A2 synthetase (TA2S) inhibition) were made. Of the 31 patients entered into the study, 23 were considered fully evaluable for response.

RESULTS

The drug was well tolerated with few side effects; no partial or complete responses were seen, but 10 patients had stable disease at 3 months; quality of life was maintained during therapy; mean CV6504 steady state plasma concentrations of 14 +/- 6 ng/ml resulting in 75 +/- 18% inhibition of TA2S were achieved; median-survival time for all patients considered eligible for assessment of efficacy was 36.6 weeks after the initial dose of study medication. The actuarial one-year survival was approximately 25%.

CONCLUSION

CV6504 inhibits its target enzyme in vivo, maintains stable disease in 32% of evaluable patients and is well tolerated.

Characterization of long-term femoral-head-penetration rates. Association with and prediction of osteolysis

BACKGROUND

We examined the relationship between long-term femoral-head-penetration patterns and osteolysis in a ten-year follow-up study of a well controlled patient population. The purposes of this study were to characterize the linearity of long-term head-penetration patterns over time, to describe the relationship between ten-year true wear rates and osteolysis, and to determine whether the occurrence of osteolysis at ten years could be predicted by penetration data obtained prior to five years.

METHODS

Temporal femoral-head-penetration patterns were examined at a minimum of ten years after forty-eight primary total hip arthroplasties. The arthroplasties were performed with the use of an Arthropor acetabular cup (Joint Medical Products) and a thirty-two-millimeter-diameter cobalt-chromium femoral head (DePuy). Using a computer-assisted radiographic technique, we evaluated two-dimensional head penetration on serial annual radiographs. Linear regression analysis modeled penetration-versus-time data as a line for each patient. The slope of the regression line indicated the true wear rate for each patient. In a subgroup of thirty-four hips for which three annual radiographs had been made less than five years after the arthroplasty, we compared early head-penetration patterns with the later occurrence of osteolysis.

RESULTS

For all forty-eight hips, the true wear rate averaged 0.18 millimeter per year (range, 0.01 to 0.44 millimeter per year) and temporal head-penetration patterns tended to be linear (mean r2 = 0.91 +/- 0.16). Osteolysis at ten years was strongly associated with increasing true wear rates (p < 0.001). Osteolysis did not develop in any of the nine hips with a true wear rate of less than 0.1 millimeter per year. However, osteolysis developed in nine (43 percent) of twenty-one hips with a rate between 0.1 and less than 0.2 millimeter per year, in eight of ten hips with a rate between 0.2 and 0.3 millimeter per year, and in all eight hips with a rate of greater than 0.3 millimeter per year. Evaluation of early true wear rates as a predictor of late osteolysis showed a similar relationship.

CONCLUSIONS

This study demonstrates that true wear rates tend to be constant and that increased true wear is significantly associated with osteolysis at ten years after the operation. A similar relationship was also found at the early follow-up interval, indicating that early true wear rates (determined from serial radiographs) might enable orthopaedists to predict if patients are at risk for the development of osteolysis.

CLINICAL RELEVANCE

On the basis of these findings, we use temporal femoral-head-penetration data in our practice to evaluate polyethylene inserts in asymptomatic patients, to estimate the time to component wear-through, and to adjust the frequency of follow-up evaluations for monitoring the development of osteolytic lesions in at-risk patients.

Discriminative stimulus effects of two doses of fentanyl in rats: pharmacological selectivity and effect of training dose on agonist and antagonist effects of mu opioids

RATIONALE

Discriminative stimulus effects of mu opioids vary systematically as a function of training dose. Differences among training doses may arise from multiple mechanisms.

OBJECTIVES

In vivo apparent pA(2) analyses were used to examine the contributions of opioid mechanisms to stimulus control by low and high training doses of the mu opioid fentanyl.

METHODS

Saline and one of two doses of fentanyl, administered s.c., were established as discriminative stimuli in two groups of rats (low training dose group: 0.01 mg/kg; high training dose group: 0.04 mg/kg). Generalization tests and in vivo apparent pA(2) analyses were used to evaluate receptor mechanisms of stimulus control.

RESULTS

Fentanyl, etonitazene, methadone, and morphine evoked full fentanyl generalization in both groups but were more potent in the low-dose group. Spiradoline and d-amphetamine did not evoke generalization in either group. Naltrexone antagonized stimulus and rate-altering effects of fentanyl in both groups, with apparent pA(2) values of 7. 6 in the low-dose group and 7.5 in the high-dose group. Nalbuphine and nalorphine evoked full generalization in the low-dose group but less than 40% generalization in the high-dose group. In the high-dose group, nalbuphine and nalorphine antagonized the stimulus and rate-altering effects of fentanyl with apparent pA(2) values of 5.3 and 6.1, respectively, demonstrating lower efficacy mu actions.

CONCLUSIONS

Changes in fentanyl training dose preserved the mu opioid selectivity of stimulus control but altered the intensity of the transduced mu opioid stimulus required for generalization. These differences in intensity of the fentanyl stimulus determined whether low efficacy mu opioids would evoke or antagonize fentanyl generalization.

On creating a workable signing environment: deaf and hearing perspectives

This article studies teams of service providers in education and psychiatric services, in which a substantial number of both deaf and hearing people work together as colleagues. It focuses specifically on the challenges involved in cooperatively creating a signing work environment. Using a methodology that draws on the principles of ethnography, it identifies and explores the meaning constructions associated with signing at work, from deaf and hearing perspectives. Data were collected through interviews in three organizations all in the United Kingdom: two specialist psychiatric units for deaf adults and a school for deaf children. Forty-one informants participated (20 deaf, 21 hearing). Results show that from a deaf perspective, hearing people's use of sign language in their presence at work is closely associated with demonstrating personal respect, value, and confidence, and hearing colleagues' willingness to sign is more significant than their fluency. From a hearing perspective, results demonstrate that sign language use at work is closely associated with change, pressure, and the questioning of professional competence. The challenges involved in improving deaf/hearing relations are perceived from a deaf perspective as largely person-centered, and from a hearing perspective as primarily language-centered. The significance of organizational factors such as imbalances in power and status between deaf and hearing colleagues is explored in relation to the findings.

Can pharmacokinetic monitoring improve clinical use of fluorouracil?

Fluorouracil is used clinically against a variety of solid tumors. It is a prodrug that undergoes a series of intracellular conversions to active cytotoxic species. There is wide interindividual variability in fluorouracil metabolism; furthermore, it has nonlinear kinetics that make it relatively more difficult to predict plasma concentrations after brief infusions compared with prolonged infusions. There is an increasing body of evidence that relates plasma fluorouracil concentrations to toxicity and effectiveness, and consequently there may be a definable mathematical relationship that describes a 'therapeutic window'. Dose nomograms and pharmacokinetic models based on limited sampling strategies have been developed, as have empirical dose escalation schedules based on multivariate analysis of the determinants of toxicity, The utility of these approaches should be tested in properly powered, prospective, randomised trials.

Preliminary clinical study of the distribution of HPMA copolymers bearing doxorubicin and galactosamine

Galactose-targeted delivery of macromolecules and drug conjugates to asialoglycoprotein receptor (ASGPR) positive cells has been widely documented in animals, although targeting in humans has never been demonstrated. In this study we report the pharmacokinetics and imaging determined in the first patient enrolled in a phase I clinical study of the poly[N-(2-hydroxypropyl)methacrylamide] copolymer bearing doxorubicin and galactosamine, known as PK2. Gradient high performance liquid chromatography (HPLC) evaluation of plasma and urine has been combined with 123I-based imaging to show biphasic clearance of the drug from the plasma (half-lives of 78+/-1 and 990+/-15), and approximately 30% delivery of the drug to the hepatic region, as determined by planar whole body imaging at 24 h. This patient has a multifocal hepatoma, and single photon emission computed tomography (SPECT) analysis showed a ratio of tumour tissue to normal liver uptake of approximately 1:3, at 24 h. On the basis of this patient, effective hepatic targeting can be achieved following an intravenous dose of 20 mg/m2 doxorubicin as PK2, however the therapeutic usefulness of this targeted drug has yet to be established.

Contoured elastic-membrane microvalves for microfluidic network integration

A contoured elastic-membrane microvalve is presented that enables integrated microfluidic processing at the network level. This method takes advantage of two ideas to improve performance: flexible elastic membranes (which enable high-performance shutoff and reduced footprint), and three-dimensionally contoured valve geometries (which reduce dead volume, improve fluidic priming, and reduce susceptibility to cavitation at high fluid velocities). We describe the use of laser-induced etching for microfluidic manifold fabrication, discuss the nonlinear load-deflection behavior of elastic membranes that can occur below 30 psi, and present flow-rate data for microvalves under inlet pressures of 0-20 psi with zero applied membrane pressure. Valve-closure data for inlet pressures of 0-30 psi are presented for fully assembled microvalve structures. The microvalve structures under test were capable of turning off flows of > 20 microL/s. These flow rates were shown to be limited by inlet and outlet flow resistances and not by the valve structure itself, so that higher maximum flow rate capabilities should be readily achieved.

Dopamine release in the amygdaloid complex of the rat, studied by brain microdialysis

The dopaminergic projection from the ventral tegmental area to the amygdaloid complex may be modulatory on the processes of associative learning in the latter region. We measured dopamine in four different amygdaloid subfields in the rat, using brain microdialysis. Extracellular levels of dopamine in two sites in the lateral nucleus were not consistently measurable, even after treatment with amphetamine. However, basal dopamine levels were measurable in more medial locations (basolateral and central nuclei), with higher concentrations in the caudal than in the rostral probe placement, and were increased around 3-fold by systemic amphetamine. Similarly, dopamine levels in caudal-medial amygdala were increased by local potassium stimulation and by mild footshock in a calcium-dependent manner, indicating a neurotransmitter origin.

Establishing morphine and U-50,488H as discriminative stimuli in a three-choice assay with pigeons

Pigeons were trained in a 3-choice assay to discriminate among injections of 5.6 mg/kg U-50,488H, 5.6 mg/kg morphine, and vehicle solution. In dose-response tests, subjects rarely responded on the U-50,488H-appropriate key when morphine was administered or on the morphine-appropriate key when they received U-50,488H. A high dose of naltrexone (1.0 mg/kg) completely blocked the morphine cue but failed to block completely the U-50,488H cue. In generalization tests, d-amphetamine primarily engendered saline-appropriate responding. Ethylketazocine produced mixed results, in that moderate doses produced responding on both the morphine- and U-50,488H-appropriate keys, but 3.2 mg/kg engendered primarily morphine-appropriate responding. These results demonstrate the feasibility, but not necessarily the value, of 3-choice discrimination procedures involving mu and kappa agonists and vehicle.