Practical Considerations for Total-Body PET Acquisition and Imaging

The world's first total-body PET/CT system has been in routine clinical and research use at UC Davis since 2019. The uEXPLORER total-body PET scanner has been designed with an axial field-of-view long enough to completely encompass most human subjects (194 cm or 76 inches long), allowing for a 15-68-fold gain in the PET signal collection efficiency over conventional PET scanners. A high-sensitivity PET scanner that can image the entire subject with a single bed position comes with new benefits and challenges to consider for efficient and practical use. In this chapter, we discuss the common clinical and research imaging protocols implemented at our institution, along with the appropriate technical and practical considerations of total-body PET imaging.

Perspectives of clinicians and patients on community-based maintenance care for adults with obesity

Background

Tertiary metabolic health services are in high demand as people with severe obesity increase. Once predetermined health goals have been achieved patients must transition to community-based care to urgently free up capacity in tertiary services. Maintenance of successful outcomes achieved via tertiary services is therefore important to limit rates of relapse back to these services.

Methods

This qualitative project explored community-based care needs to help individuals living with obesity maintain health gains. An interview schedule guided one-on-one interviews with patients and staff from metabolic clinics in Sydney, Australia.

Results

We interviewed 22 patients and 13 clinicians. A lack of appropriate and consistent clinical support in the community was identified by patients and clinicians. Most clinicians agreed primary care was key to successful maintenance care. Lack of primary care understanding of appropriate management and support for patients with obesity, lack of bariatric equipment and limited funding for allied health were all seen barriers to appropriate support beyond their clinics. Patients were highly reluctant to transition from tertiary clinics and reluctant to engage with community-based care due to experience of limited clinical/social support and bariatric equipment, demeaning clinical interactions, lack of care coordination and being stigmatised. Support groups outside of the clinic were also identified important in mitigating social isolation and stigma. Both patients and clinicians felt support groups have potential to provide important supplementary help to individuals with obesity outside tertiary settings.

Conclusions

Currently, individuals aiming to maintain their weight are likely to struggle in the context of existing community care provisions. Integrated, community-based and affordable models of care are needed now to allow tertiary metabolic services discharge their patients safely.

Key messages

• Tertiary obesity services are at capacity.

• Subsequent community care for people wth obesity needs to be mote appropriate tp promote weight maintenance.

Impact of BMI on breast screening participation: a data linkage study

Background

Regular mammographic screening can reduce breast cancer morbidity and mortality. Participation rates are suboptimal in Australia’s fully funded biennial breastscreening program (BreastScreen) for women aged 50-74. Despite obesity being a well-established risk factor for post-menopausal breast cancer, cross sectional data suggests obesity may be a risk factor for non-participation in recommended screening, due to adverse screening experiences. This research aimed to ascertain the link obesity and non-participation by using data linkage of routinely collected data.

Methods

Data for women age eligible for breast screening were linked between the NSW Cancer Registry and the Australian Longitudinal Study of Women’s Health (ALSWH) to create a cohort of women who either participated in screening as recommended or not. Women from the 1946-1951 ALSWH birth cohort were included in the study. These women reported BMI via 8 survey waves. The primary outcome was adherence to breast screening measured by frequency of screening over the follow-up period (1998-2016). Unadjusted risk ratios were calculated using mixed-effects logistic regression for the association between BMI and screening participation.

Results

The study included 2804 linked records of age eligible women (mean age of 52.37[SD 5.47]). 22.8% of the cohort were obese (BMI>30kg/m2). Obesity was significantly associated with non-recommended screening participation (screening within 3 years of last breast screen); odds ratio 1.63 (95% confidence interval 1.32 to 2.00, p < 0.0001).

Conclusions

Obesity has a significantly impact on recommended participation in a nationally provided breast screening program, despite obesity being a risk factor for post- menopausal breast cancer. Optimising participation among higher risk and under-screened women in under utilised breast cancer screening programs is warranted. Development of targeted interventions to increase screening participation among these higher risk women is needed.

Key messages

• Women living with obesity and less likely to participate in recommended breast screening.

• Targeted interventions are needed to optimise participation in breast screening to ensure these higher risk women are not at higher risk of adverse outcomes due to breast cancer.

Total-Body 18F-FDG PET/CT in Autoimmune Inflammatory Arthritis at Ultra-Low Dose: Initial Observations

Autoimmune inflammatory arthritides (AIA), such as psoriatic arthritis (PsA) and rheumatoid arthritis (RA), are chronic systemic conditions that affect multiple joints of the body. Recently, total-body (TB) PET/CT scanners have become available that exhibit superior technical characteristics (total-body coverage, geometric sensitivity) that could benefit AIA evaluation, compared to conventional PET/CT systems. The objectives of this work were to (1) assess the performance of an ultra-low-dose, ¹⁸F-FDG TB-PET/CT acquisition protocol for evaluating systemic joint involvement in AIA; and (2) report the association of TB-PET/CT measures with joint-by-joint rheumatologic examination and standardized rheumatologic outcome measures. Methods: Thirty participants (24 with AIA and 6 with osteoarthritis (OA)), were prospectively enrolled in this single-center, observational study. All participants underwent a TB-PET/CT scan for 20 min starting at 40 min after intravenous injection of 78.1±4.7 MBq of ¹⁸F-FDG. Qualitative and quantitative evaluation of ¹⁸F-FDG uptake and joint involvement were performed from the resulting images and compared with the rheumatologic assessments. Results: TB-PET/CT enabled the visualization of ¹⁸F-FDG uptake at joints of the entire body, including those of the hands and feet, in a single bed position, and in the same phase of radiotracer uptake. A range of pathologies consistent with AIA (and non-AIA in the OA group) were visualized, and the feasibility of extracting PET measures from joints examined by rheumatologic assessments was demonstrated. Out of 1997 evaluable joints, there was concordance between TB-PET qualitative assessments and joint-by-joint rheumatologic evaluation in the AIA and non-AIA cohorts for 69.9% and 91.1% joints, respectively, while an additional 20.1% and 8.8% joints, respectively, deemed negative on rheumatologic examination showed PET-positivity. On the other hand, 10.0% and 0% joints in the AIA and non-AIA cohorts, respectively, were positive on rheumatologic evaluation but negative on TB-PET. Quantitative measures from TB-PET in the AIA cohort demonstrated a moderate to strong correlation (Spearman's ρ=0.53-0.70, p<0.05) with the rheumatologic outcome measures. Conclusion: Systemic joint evaluation in AIA (and non-AIA) is feasible with a TB-PET/CT system and an ultra-low-dose protocol. Our results provide the foundation for future larger studies to evaluate the possible improvements in AIA joint assessment via the TB-PET/CT technology.

Blanching Defects at the Pressure Points: Observations from Dynamic Total-Body PET/CT Studies

Total-body PET/CT allows simultaneous acquisition of all the body parts in a single bed position during the radiotracer uptake phase. Dynamic imaging protocols employing total-body PET could demonstrate findings that may not have been previously visualized or described using conventional PET/CT scanners. We examined the characteristics of blanching defects, areas of markedly reduced (partial defect) or absent (complete defect) radiotracer uptake seen at the skin/subcutaneous tissues opposite the bony prominences at pressure points. Methods: In this observational study, 77 participants underwent dynamic total-body PET/CT imaging using 18F-FDG (Group 1, N = 47, 60-min dynamic, arms-down, divided into 3 subgroups according to the injected dose) or 18F-fluciclovine (Group 2, N = 30, 25-min dynamic, arms above the head). 40 out of 47 participants in Group 1 were re-imaged at 90 min after being allowed off the scanning table. Blanching defects, partial or complete, were characterized opposite the bony prominences at 7 pressure points (the skull, scapula, and calcaneus bilaterally, as well as the sacrum). Association of the blanching defects with different clinical and technical characteristics were analyzed using uni- and multi-variate analyses. Results: A total of 124 blanching defects were seen in 68 out of 77 (88%) participants at one or more pressure points. Blanching defects were higher, on average, in Group 2 participants (3.5±1.7) compared to Group 1 (2.1±1.4; P <0.001), but it did not vary within Group 1 for different 18F-FDG dose subgroups. All defects resumed normal pattern on delayed static (90-min) images except for 14 partial defects. No complete blanching defects were seen on the 90-min images. By multivariate analysis, arm positioning above the head was associated with skull defects; scapular and sacral defects were significantly more encountered in men and with lower BMI, while calcaneal defects could not be associated to any factor. Conclusion: Blanching defects opposite the bony pressure points are common on dynamic total-body PET/CT images using different radiopharmaceuticals and injection doses. Their appearance should not be immediately interpreted as an abnormality. The current findings warrant further exploration in a prospective setting and may be utilized to study various mechano-pathologic conditions, such as pressure ulcers.

Unusual Near-Horizon Cosmic-Ray-like Events Observed by ANITA-IV

ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0.27} anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous noninverted polarity, a p=5.3×10^{-4} chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply upcoming anomalous events similar to the two such events seen in prior flights.

Possible clearance of transfusion-acquired nef/LTR-deleted attenuated HIV-1 infection by an elite controller with CCR5 Δ32 heterozygous and HLA-B57 genotype

BACKGROUND

Subject C135 is one of the members of the Sydney Blood Bank Cohort, infected in 1981 through transfusion with attenuated nef/3' long terminal repeat (LTR)-deleted HIV-1, and has maintained undetectable plasma viral load and steady CD4 cell count, in the absence of therapy. Uniquely, C135 combines five factors separately associated with control of viraemia: nef/LTR-deleted HIV-1, HLA-B57, HLA-DR13, heterozygous CCR5 Δ32 genotype and vigorous p24-stimulated peripheral blood mononuclear cell (PBMC) proliferation. Therefore, we studied in detail viral burden and immunological responses in this individual.

METHODS

PBMC and gut and lymph node biopsy samples were analysed for proviral HIV-1 DNA by real-time and nested PCRs, and nef/LTR alleles by nested PCR. HIV-specific antibodies were studied by Western blotting, and CD4+ and CD8+ T lymphocyte responses were measured by proliferation and cytokine production in vitro.

RESULTS

PBMC samples from 1996, but not since, showed amplification of nef alleles with gross deletions. Infectious HIV-1 was never recovered. Proviral HIV-1 DNA was not detected in recent PBMC or gut or lymph node biopsy samples. C135 has a consistently weak antibody response and a substantial CD4+ T cell proliferative response to a previously described HLA-DR13-restricted epitope of HIV-1 p24 in vitro, which augmented a CD8+ T cell response to an immunodominant HLA-B57-restricted epitope of p24, while his T cells show reduced levels of CCR5.

CONCLUSIONS

Subject C135's early PCR and weak antibody results are consistent with limited infection with a poorly replicating nef/LTR-deleted strain of HIV-1. With his HLA-B57-restricted gag-specific CD8 and helper HLA-DR13-restricted CD4 T cell proliferative responses, C135 appears to have cleared his HIV-1 infection 37 years after transfusion.

Evaluation of La1−xSrxMnO3 (0 ≤ x < 0.4) synthesised via a modified sol–gel method as mediators for magnetic fluid hyperthermia

A range of lanthanum strontium manganates (La_1−xSr_xMnO₃) where 0 ≤ x ≤ 0.4 were prepared using a modified peroxide sol–gel synthesis. The crystal structure of these materials was investigated and their potential as mediators for magnetic fluid hyperthermia was evaluated.

A Phase 1b/2a study of the safety, pharmacokinetics and antiviral activity of BIT225 in patients with HIV-1 infection

OBJECTIVES

BIT225 (N-carbamimidoyl-5-(1-methyl-1H-pyrazol-4-yl)-2-naphthamide), a novel acyl-guanidine, is a novel antiviral drug that blocks Vpu ion channel activity and has anti-HIV-1 activity in vitro. The antiviral effect of BIT225 is most pronounced in cells of the myeloid lineage. With infected circulating monocytes and tissue-resident macrophages representing a key cellular reservoir of HIV-1, BIT225 has a potential role in the eradication of the virus from the host.

PATIENTS AND METHODS

BIT225-004 is a Phase 1b/2a, placebo-controlled, randomized study of the safety, pharmacokinetics and antiviral activity of BIT225 in 21 HIV-1-infected, ART-naive subjects. Twenty-one subjects were enrolled and received BIT225 (400 mg twice daily) or placebo treatment for 10 days (randomized 2:1). The anti-HIV-1 effect of BIT225 in the monocyte reservoir was measured in CD14+ monocytes isolated from the peripheral blood on days 1 (pre-dose), 5, 10 and 20; isolated monocytes were co-cultured ex vivo with MT4 T cells. De novo HIV-1 replication was measured by p24 activity of released virus into the culture supernatant to day 25 of co-culture. In addition, monocyte samples were collected for analysis by RT-PCR total HIV-1 DNA single-copy assay.

RESULTS

Measurement of HIV-1 directly within the patient's monocyte population indicated that BIT225 treatment significantly reduced the viral burden in myeloid lineage cells, which was more evident in those individuals with the highest viral loads. In addition, BIT225-treated subjects demonstrated a significantly reduced level of monocyte activation (sCD163) compared with the placebo controls.

CONCLUSIONS

This study's unique design demonstrates that BIT225 can significantly reduce the dissemination of HIV-1 from infected monocytes. This has important ramifications for diminishing the seeding/re-seeding of the viral reservoir.

Clinical management patterns and treatment outcomes in patients with non-small cell lung cancer (NSCLC) across Europe: EPICLIN-Lung study

BACKGROUND

Throughout Europe, physicians face similar challenges in non-small cell lung cancer (NSCLC) management, but comprehensive international information on usual clinical practice is lacking so the burden of NSCLC is not fully understood.

METHODS

This multinational, multicentre, non-interventional study (NCT00831909) was conducted in eight European countries. Patients with confirmed NSCLC were consecutively enrolled from January to March 2009 and followed for 12 months or until death. Information was collected on patient and disease characteristics, diagnosis and treatment patterns, and clinical outcomes. Spontaneously reported adverse events (AEs) were also recorded.

RESULTS

Data were available for 3508 patients. Most patients (77.5%) were male, median (range) age was 65.0 years (21.6-90.7), the majority of patients had a World Health Organization performance status of ≤1 (74.7%), and 10.8% were never smokers. The most prevalent histologies were adenocarcinoma (43.8%) and squamous-cell carcinoma (29.4%). Most patients presented with advanced disease (11.6% with stage IIIA, 18.7% with stage IIIB, 48.6% with stage IV). In stage IV disease, median progression-free survival and overall survival (months) by first-line treatment cluster were platinum regimens: 6.5, 10.8; non-platinum regimens: 4.3, 8.5; regimens with bevacizumab 8.7, 12.9; investigational regimens: 5.6, 10.8; best supportive care: 5.4, 6.6. The most frequently reported severe (Common Terminology Criteria for Adverse Events v3.0>2) AEs were blood/bone marrow (16.0%) and pulmonary/upper respiratory (7.8%). Key limitations of this study related to its non-interventional nature and wide regional focus; for example, achieving a representative sample of the overall NSCLC population, variation in recruitment between countries, and data based on information from medical records derived from routine visits.

CONCLUSIONS

The Epidemiological Study to Describe NSCLC Clinical Management Pattern in Europe-Lung (EPICLIN-Lung) study provides new insights into the descriptive patterns and clinical management strategies for NSCLC across Europe, and how they affect patient outcomes.

Short communication: HIV blips while on antiretroviral therapy can indicate consistently detectable viral levels due to assay underreporting

Viral blips, where HIV RNA plasma viral load (pVL) intermittently increases above the lower limit of assay detection, are a cause for concern. We investigated a number of hypotheses for their cause. We assessed HIV RNA, and total and episomal HIV DNA from 16 individuals commencing antiretroviral therapy (ART) consisting of raltegravir and tenofovir/emtricitabine for 3 years, using two assays: a single-copy assay [SCA; lower limit of quantification (LLOQ), <1 copy/ml] and the Amplicor assay (LLOQ of 50 copies/ml). Two individuals exhibited viral blips. From week 20 onward, the period where ART had achieved its final suppressive levels, pVL ranged from <1 to 330 copies/ml, except for one individual at the final time. Both assays were 98% consistent (108/110) in assessing pVL <50 copies/ml, but the Amplicor assay registered 56% of samples (19/34) as below the LLOQ that were in the 50 to 1000 copy/ml range as quantified by SCA. pVL changes between successive time points did not correlate with changes in cellular infection as measured through either total or episomal HIV DNA. Changes in pVL were correlated (negatively) with changes in total CD4(+) T cell numbers (p=0.003), naive (CD45RO(-)CD62L(+)CD4(+)), natural regulatory (CD45RO(-)CD25(+)CD127(-)CD4(+)), activated effector (CD45RO(+)CD38(++)CCR5(+)CD8(+)), but not activated (CD38(+)HLA-DR(+)) CD4(+) T cells. Patients receiving stable, seemingly suppressive ART can have pVL near the 50 copy LLOQ at multiple time points. The high Amplicor assay error rate around this level implies that viral blips underrepresent pVL being more consistently above the LLOQ. Activation of latently infected cells is less likely to contribute to this phenomenon.

The majority of HIV type 1 DNA in circulating CD4+ T lymphocytes is present in non-gut-homing resting memory CD4+ T cells

Memory CD4(+) T lymphocytes in peripheral blood that express integrins α4ß7 preferentially recirculate through gut-associated lymphoid tissue (GALT), a proposed site of significant HIV-1 replication. Tregs and activated CD4(+) T cells in GALT could also be particularly susceptible to infection. We therefore hypothesized that infection of these subsets of memory CD4(+) T cells may contribute disproportionately to the HIV-1 reservoir. A cross-sectional study of CD4(+) T cell subsets of memory CD45RO(+) cells in peripheral blood mononuclear cells (PBMCs) was conducted using leukapheresis from eight subjects with untreated chronic HIV-1 infection. Real-time polymerase chain reaction (PCR) was used to quantify total and integrated HIV-1 DNA levels from memory CD4(+) T cells sorted into integrin β7(+) vs. β7(-), CD25(+)CD127(low) Treg vs. CD127(high), and activated CD38(+) vs. CD38(-). More than 80% of total HIV-1 DNA was found to reside in the integrin β7-negative non-gut-homing subset of CD45RO(+) memory CD4(+) T cells. Less than 10% was found in highly purified Tregs or CD38(+) activated memory cells. Similarly, integrated HIV-1 DNA copies were found to be more abundant in resting non-gut-homing memory CD4(+) T cells (76%) than in their activated counterparts (23%). Our investigations showed that the majority of both total and integrated HIV-1 DNA was found within non-gut-homing resting CD4(+) T cells.

Progressive activation of CD127+132- recent thymic emigrants into terminally differentiated CD127-132+ T-cells in HIV-1 infection

Aim

HIV infection is associated with distortion of T-cell homeostasis and the IL-7/IL7R axis. Progressive infection results in loss of CD127+132− and gains in CD127−132+ CD4+ and CD8+ T-cells. We investigated the correlates of loss of CD127 from the T-cell surface to understand mechanisms underlying this homeostatic dysregulation.

Methods

Peripheral and cord blood mononuclear cells (PBMCs; CBMC) from healthy volunteers and PBMC from patients with HIV infection were studied. CD127+132−, CD127+132+ and CD127−132+ T-cells were phenotyped by activation, differentiation, proliferation and survival markers. Cellular HIV-DNA content and signal-joint T-cell receptor excision circles (sjTRECs) were measured.

Results

CD127+132− T-cells were enriched for naïve cells while CD127−132+ T-cells were enriched for activated/terminally differentiated T-cells in CD4+ and CD8+ subsets in health and HIV infection. HIV was associated with increased proportions of activated/terminally differentiated CD127−132+ T-cells. In contrast to CD127+132− T-cells, CD127−132+ T-cells were Ki-67+Bcl-2^low and contained increased levels of HIV-DNA. Naïve CD127+132− T-cells contained a higher proportion of sjTRECs.

Conclusion

The loss of CD127 from the T-cell surface in HIV infection is driven by activation of CD127+132− recent thymic emigrants into CD127−132+ activated/terminally differentiated cells. This process likely results in an irreversible loss of CD127 and permanent distortion of T-cell homeostasis.

Sperm traits in Chinook salmon depend upon activation medium: implications for studies of sperm competition in fishes

Sperm traits of externally fertilizing fish species are typically measured in fresh (or salt) water, even though the spawning environment of their ova contains ovarian fluid. In this study, we measured sperm traits of Chinook salmon ( Oncorhynchus tshawytscha (Walbaum in Artedi, 1792)) in both fresh water and dilute ovarian fluid at 10 and 20 s postactivation, using a computer-assisted sperm analysis system. Spermatozoa swam faster, and had both higher percent motility and a straighter path trajectory for a longer period of forward motility when activated in ovarian fluid compared with activation in fresh water. Comparing sperm activity of 10 males in water versus ovarian fluid, we found a weak but significant correlation for sperm swimming speed at 10 s postactivation (r = 0.34, p = 0.01), but not for any other sperm traits measured. Most important, across males, mean sperm swimming speed in water accounted for <10% of the observed variation in mean sperm swimming speed in ovarian fluid. Thus, we argue that sperm traits measured in fresh water are not particularly relevant to those same traits during normal spawning in this species. We suggest that sperm performance measured in fresh water should be used with caution when comparing the potential for individual males to fertilize ova, especially in studies of sperm competition in externally fertilizing species.

Formative design and evaluation of patient-delivered partner therapy informational materials and packaging

OBJECTIVE

To develop and evaluate instructional and packaging materials for patient-delivered partner therapy (PDPT).

METHODS

64 patients participated from an urban US sexually transmitted infection (STI) clinic. The research comprised three phases: individual interviews to elicit attitudes and beliefs regarding PDPT and to assess the understanding of key STI-related concepts and terminology; the development and rapid validation of prototype instructional and packaging materials for PDPT and interviews to assess the effectiveness, acceptability and usability of the prototype materials. Thematic qualitative data analysis was used to examine interview responses.

RESULTS

Participants were willing to deliver and receive PDPT and several potentially important related beliefs were identified. Participants indicated substantial unfamiliarity with words associated with STI treatment and some variability in definitions of sex partners. PDPT informational materials differentially affected participant willingness to receive (positively) and deliver (negatively) PDPT, positively influenced self-efficacy and understanding and were perceived as easy to use.

DISCUSSION

PDPT creates complex challenges for education, motivation and communication. Issues such as appropriate vocabulary and interpersonal trust may be amplified when responsibility for a medical procedure-dispensation of treatment-is shifted to patients. STI PDPT implementation can be augmented with effective, high-quality informational and packaging materials; however, several challenges exist.

Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure

Emissions of ammonia, as well as other gases and particulates, to the atmosphere are a growing concern of livestock producers, the general public, and regulators. The concentration and ruminal degradability of CP in beef cattle diets may affect urinary and fecal excretion of N and thus may affect ammonia emissions from beef cattle feed yards. To determine the effects of dietary CP concentration and degradability on potential ammonia emissions, 54 steers were randomly assigned to nine dietary treatments in a 3 x 3 factorial arrangement of treatments. Treatments consisted of three dietary CP concentrations (11.5, 13, and 14.5%) and three supplemental urea:cottonseed meal ratios (100:0, 50:50, and 0:100 of supplemental N). Steers were confined to tie stalls, and feces and urine excreted were collected and frozen after approximately 30, 75, and 120 d on feed. One percent of daily urine and feces excretion were added to polyethylene chambers containing 1,550 g of soil. Chambers were sealed, and ammonia emissions were trapped in an acid solution for 7 d using a vacuum system. As the protein concentration in the diet increased from 11.5 to 13%, in vitro daily ammonia emissions increased (P < 0.01) 60 to 200%, due primarily to increased urinary N excretion. As days on feed increased, in vitro ammonia emissions also increased (P < 0.01). Potential ammonia losses were highly correlated (P < 0.01) to urinary N (r2 = 0.69), urinary urea-N (r2 = 0.58) excretion, serum urea-N concentration (r2 = 0.52), and intake of degradable protein N (r2 = 0.23). Although dietary composition can affect daily ammonia losses, daily ammonia emissions must be balanced with effects on animal performance to determine optimal protein concentrations and forms in the diet.

Men with broken condoms: who and why?

OBJECTIVES

To identify (1) the prevalence of condom breakage, and demographic and sexuality-related differences among young men who have sex with women reporting and not reporting this event; (2) condom-specific behaviours associated with breakage.

METHODS

Young men (n = 278) attending a clinic for treatment of sexually transmitted infections (STIs) responded to an anonymous questionnaire aided by a CD recording of the questions. The samples were screened to include only men who had used a condom during penile-vaginal sex at least three times in the past 3 months. Condom-specific behaviours (including breakage) were assessed using these last three acts of condom use as the recall period. Correlates achieving bivariate significance were subjected to multivariate analysis.

RESULTS

Nearly one third (31.3%) of the men reported recent breakage. The breakage rate was 15%. Three correlates significantly distinguished between men who did and did not report breakage. Men who had past STIs were more likely to report breakage (adjusted odds ratio (AOR) 2.08), as were men who also reported condom slippage (AOR 2.72). Less self-efficacy for correct condom use was also significantly associated with breakage (AOR 1.07). Further, three condom-specific behaviours were significantly associated with breakage: allowing condoms to contact sharp objects (AOR 2.6), experiencing problems with the "fit or feel" of condoms (AOR 2.3) and not squeezing air from the receptacle tip (AOR 2.0).

CONCLUSIONS

Breakage may be common and may occur in a larger context of difficulties with condoms. STI clinics could potentially benefit some men by providing instructions on the correct use of condoms.

Influence of oscillating dietary crude protein concentration on performance, acid-base balance, and nitrogen excretion of steers

Decreasing dietary N inputs into beef cattle feeding operations could potentially decrease environmental concerns relating to air and water quality. Previous studies with sheep suggest that oscillating dietary CP concentrations may improve N use efficiency and thereby decrease dietary N requirements. Therefore, two studies were conducted to determine the effects of oscillating dietary CP concentrations on performance, acid-base balance, and manure characteristics of steers fed high-concentrate diets. Steers were fed to a constant backfat thickness in both studies. In the first trial, 92 steers (mean BW = 408 +/- 2.8 kg; four pens/treatment) were fed the following diets: 1) constant 12% CP, 2) constant 14% CP, and 3) 10 and 14% CP oscillated at 2-d intervals. Steer performance and carcass characteristics were measured. In the second trial, 27 steers were individually fed the same three experimental dietary regimens (nine steers/treatment). Animal performance, arterial acid-base balance, plasma metabolites, and fecal characteristics were measured. In both trials, steers fed the 14% CP diet tended (P < 0.10) to have greater ADG and gain:feed than steers fed the 12% CP diet. Steers fed the oscillating CP regimen had intermediate performance. In Trial 1, steers fed the 14% CP diet tended (P = 0.09) to have smaller longissimus area and higher quality grades than steers fed the oscillating CP regimen. Protein retentions (g/d) calculated from NRC (2000) equations were greater (P = 0.04) for steers fed the 14% CP diet than steers fed the 12% CP diet. Steers fed the oscillating CP regimen tended (P = 0.08) to have greater calculated protein retention (g/d) than steers fed the 12% CP diet. Steers fed the 14% CP diet had greater (P < 0.05) calculated urinary N excretion than steers fed the 12% CP or oscillating CP regimens. Venous plasma concentrations of urea N were greater (P < 0.001) in steers fed the 14% CP diet than in steers fed the 12% CP diet; steers fed the oscillating CP regimen were intermediate but fluctuated over days. Based on arterial blood gas concentrations, acid-base balance was not significantly affected by dietary CP regimen. Results of these trials suggest that the CP requirement of steers in these studies was greater than 12% of the diet DM, and/or that the degradable CP requirement was greater than 6.3% of diet DM. However, the effects of oscillating dietary CP were minimal.

Regulation of the ANF and BNP promoters by GATA factors: lessons learned for cardiac transcription

The identification and molecular cloning of the cardiac transcription factors GATA-4, -5, and -6 has greatly contributed to our understanding of how tissue-specific transcription is achieved during cardiac growth and development. Through analysis of their interacting partners, it has also become apparent that a major mechanism underlying spatial and temporal specificity within the heart as well as in the response to cardiogenic regulators is the combinatorial interaction between cardiac-restricted and inducible transcription factors. The cardiac GATA factors appear to be fundamental contributors to these regulatory networks. Two of the first targets identified for the cardiac GATA factors were the natriuretic peptide genes encoding atrial natriuretic factor (ANF) and B-type natriuretic peptide (BNP), the major heart secretory products that are also accepted clinical markers of the diseased heart. Studies using the ANF and BNP promoters as models of cardiac-specific transcription have unraveled the pivotal role that GATA proteins play in cardiac gene expression. We review the current knowledge on the modulation of the natriuretic peptide promoters by GATA factors, including examples of combinatorial interactions between GATA proteins and diverse transcription factors.

Alterations in brain function after loss of docosahexaenoate due to dietary restriction of n-3 fatty acids

The concentration of the major polyunsaturated fatty acid (PUFA) in brain, docosahexaenoate, may be markedly reduced by two or more generations of dietary restriction of sources of n-3 fatty acids in the diet. Such a deficiency was induced through the feeding of safflower oil as the principal source of essential fatty acids. The reference point for this diet was an n-3 adequate diet to which alpha-linoleate and docosahexaenoate were added through the addition of a small quantity of flax seed or algael oils, respectively. The loss of brain DHA was associated with poorer performance in spatial tasks and an olfactory-cued reversal learning task. No difference could be observed in the hippocampal gross morphology. This study demonstrates the importance of providing a source of n-3 fatty acids during mammalian growth and development.

Secondary hypoxemia exacerbates the reduction of visual discrimination accuracy and neuronal cell density in the dorsal lateral geniculate nucleus resulting from fluid percussion injury

The purpose of this study was to determine the impact of secondary hypoxemia on visual discrimination accuracy after parasagittal fluid percussion injury (FPI). Rats lived singly in test cages, where they were trained to repeatedly execute a flicker-frequency visual discrimination for food. After learning was complete, all rats were surgically prepared and then retested over the following 4-5 days to ensure recovery to presurgery levels of performance. Rats were then assigned to one of three groups [FPI + Hypoxia (IH), FPI + Normoxia (IN), or Sham Injury + Hypoxia (SH)] and were anesthetized with halothane delivered by compressed air. Immediately after injury or sham injury, rats in groups IH and SH were switched to a 13% O2 source to continue halothane anesthesia for 30 min before being returned to their test cages. Anesthesia for rats in group IN was maintained using compressed air for 30 min after injury. FPI significantly reduced visual discrimination accuracy and food intake, and increased incorrect choices. Thirty minutes of immediate posttraumatic hypoxemia significantly (1) exacerbated the FPI-induced reductions of visual discrimination accuracy and food intake, (2) further increased numbers of incorrect choices, and (3) delayed the progressive recovery of visual discrimination accuracy. Thionine stains of midbrain coronal sections revealed that, in addition to the loss of neurons seen in several thalamic nuclei following FPI, cell loss in the ipsilateral dorsal lateral geniculate nucleus (dLG) was significantly greater after FPI and hypoxemia than after FPI alone. In contrast, neuropathological changes were not evident following hypoxemia alone. These results show that, although hypoxemia alone was without effect, posttraumatic hypoxemia exacerbates FPI-induced reductions in visual discrimination accuracy and secondary hypoxemia interferes with control of the rat's choices by flicker frequency, perhaps in part as a result of neuronal loss and fiber degeneration in the dLG. These results additionally confirm the utility of this visual discrimination procedure as a sensitive, noninvasive means of assessing behavioral function after experimental traumatic brain injury.

Malignant superior vena cava obstruction: stent placement via the subclavian route

Over a 3-year period 23 patients with malignant superior vena cava obstruction were referred for interventional management. They underwent repeat localized central venography and deployment of self-expanding Wallstents. All patients (age range 26-89 years) were approached by the subclavian route using 29 stents. The stent was used to exclude thrombus in the contralateral brachiocephalic vein in five patients and histologic information was available in all patients. Retrospective analysis of the clinical records was used to assess symptom-free survival and symptom recurrence. All patients reported an improvement in symptoms within 24 hr of the procedure. There was 100% technical success. Primary clinical success was achieved in 19 of 23 patients followed-up to their death with no symptom recurrence (range 1-34, mean 15 weeks). In four patients symptoms recurred but only one patient was referred for re-intervention, which was successful. Complications included single cases of early post-stent rethrombosis, distal slip on deployment, and distal slip on balloon dilatation. There were no puncture-related complications.

The use of endovascular stents in the treatment of penetrating ulcers of the thoracic aorta

Penetrating atheromatous ulcers of the aorta are increasingly recognized as a distinct entity. Although their natural history remains ill-defined, such ulcers may lead to pseudoaneurysmal formation, dissection, rupture, or embolization. Given the morbidity associated with open repair, endovascular repair of penetrating atheromatous ulcers may be the treatment of choice. Although stent-graft replacement of acute aortic dissections has recently been described, endovascular repair of penetrating thoracic aortic ulcers has not previously been reported. We report two cases of successful endovascular repair of penetrating atheromatous ulcers that previously ruptured.

Vascular surgical society of great britain and ireland: percutaneous transluminal angioplasty for lower limb ischaemia

BACKGROUND: Percutaneous transluminal angioplasty (PTA) is increasingly performed for lower limb ischaemia of all severities, despite the absence of controlled data demonstrating its efficacy. The aim of this study was to examine the indications and outcome for lower limb ischaemia over a 16-year period. METHODS: A prospectively gathered database of 1287 consecutive PTAs performed between 1982 and 1997 was analysed. Two time intervals were compared: 1982-1991 and 1992-1997. RESULTS: Since 1992 there has been a fourfold increase in the number of PTAs performed. There has been a significant increase in the number of PTAs performed for critical ischaemia, occlusive lesions and at infrainguinal sites. Although there has been a significant reduction in morbidity, the number of immediate technical and clinical failures has increased (see Table ). CONCLUSION: Despite a lack of controlled data supporting a more liberal use of PTA in the treatment of lower limb ischaemia, there has been, in this regional vascular unit, a significant increase in the perceived clinical and anatomical indications for the procedure. Randomized controlled trials are urgently required to define the role of PTA in this condition.

Vascular surgical society of great britain and ireland: outcome of iliac percutaneous transluminal angioplasty with and without the use of stents in patients with intermittent claudication

BACKGROUND: Despite the absence of controlled data supporting endovascular treatment of iliac disease in patients with intermittent claudication (IC), there has been a significant increase in iliac percutaneous transluminal angioplasty (PTA), and in particular iliac stenting, in recent years. The clinical and haemodynamic outcome of iliac PTA, with and without stenting, was assessed in patients with IC. METHODS: A prospectively gathered computerized database of iliac PTA (n = 203) and stenting (n = 88), performed between 1 January 1991 and 31 December 1997, was analysed. RESULTS: Occlusive disease was significantly more likely than stenotic disease to be treated by primary stent deployment (19 of 88, 22 per cent) than PTA alone (11 of 203, 5 per cent) (P < 0.01, chi2 test), as were lesions in the common iliac artery (common 69 of 214 (32 per cent) versus external 14 of 65 (22 per cent); P < 0.05, chi2 test). Primary stent placement was associated with a significant increase in morbidity that delayed hospital stay (13 of 88 (15 per cent) versus seven of 203 (3 per cent); P < 0.05, chi2 test). Emergency revascularization was required in four patients who underwent PTA (2 per cent) and two who had stenting (2 per cent) (P not significant). CONCLUSION: Iliac stenting is associated with a significant increase in morbidity but with no improvement in symptomatic or haemodynamic outcome. These results do not justify the increased expense associated with the routine use of iliac stents.