Distribution of high sensitivity troponin taken without conventional clinical indications in critical care patients and its association with mortality

Background

High sensitivity troponin (hs-cTn) concentrations above the manufacturer's upper limit of normal (ULN) are frequently seen outside the context of MI, particularly in critical care units. The current evidence regarding the prognostic value of hs-cTn in critical care settings is discrepant.

Purpose

To describe the distribution of hs-cTn in a consecutive cohort of patients in critical care units, regardless of whether there is a conventional clinical indication, and the association of this distribution with clinical outcomes.

Methods

Consecutive patients admitted to three adult critical care units (cardiothoracic (CCU), general (GCU), neuroscience (NCU)) over a six month period had hs-cTnI tests performed serially throughout the admission, regardless of whether the supervising team felt there was a clinical indication. The results were nested and not revealed to patients or clinicians unless they were requested as part of routine care. The hs-cTnI results were correlated with parameters of clinical outcome.

Results

After excluding those diagnosed with a type 1 MI, there were 1,563 patients remaining in the study cohort (CCU 530, GCU 750, NCU 283). The median hs-cTnI was 77ng/L (IQR 11–1932ng/L, with 1081 (69.2%) patients above the manufacturer-provided ULN. Overall there was a bimodal distribution; GCU and NCU were positively skewed and CCU negatively skewed. Hs-cTnI concentrations above the ULN were associated with age, comorbidity, illness severity and need for organ support (table 1). The degree by which the hs-cTnI concentration was above the ULN remained an independent predictor of critical care mortality (figure 1) in NCU and GCU.

Conclusion

Hs-cTnI elevation taken outside the context of conventional clinical indications is common in the critically ill and is associated with age, comorbidity and illness severity. Admission hs-cTnI is an independent predictor of mortality and provides additional discriminative ability to the APACHE II score alone. This assay may represent a novel prognostic biomarker on admission in non-CCU critical care settings.

Mortality relative to ULN

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Beckman Coulter

Abstract PD10-03: Predictive value of a proliferation score (MS) in postmenopausal women with endocrine-responsive breast cancer: results from International Breast Cancer Study Group (IBCSG) Trial IX

Background: While representing the largest fraction of women diagnosed with primary breast cancer, older postmenopausal women with ER+, HER2− tumors are less responsive to chemoendocrine therapy than younger women and have been underrepresented in molecular profiling of randomized trials. IBCSG Trial IX, a randomized controlled trial in postmenopausal women, median age 61y, with node negative disease, failed to demonstrate the benefit of preceding tamoxifen (T) by 3 cycles of CMF for ER+ tumors. We sought to determine if MS, a proliferation score, could identify a subset of women who differentially benefit from addition of chemotherapy to T in this trial.

Methods: From 1988–1999, 1669 eligible patients (1040 with ER+, HER2− tumors) were randomized to CMF→T vs T. Disease-free survival (DFS) was the primary trial endpoint; breast cancer-free interval (BCFI) which excludes second (non-breast) malignancies and censors deaths without prior cancer event was also evaluated. Analysis was limited to the first 7 years of follow-up. From 671 (ER+, HER2−) available subjects, 568 were successfully profiled by RT-PCR. The mRNA expression levels of 14 equally-weighted proliferation genes and 3 normalization genes were used to generate MS; predetermined binary categorization of MS was used. Analysis of this post hoc, pre-specified study used results from centralized laboratory IHC and Cox models to assess the predictive value of MS on DFS and BCFI, adjusting for traditional risk factors of local treatment, age, ER, PR, Ki67, tumor size and grade.

Results: Subgroups of MS (low, 169 samples (30%) and high, 399 samples (70%)) were identified. MS by treatment interaction was significant for DFS and BCFI (each p ≤ 0.004). Among patients with low MS, CMF→T improved DFS (HR 0.19, 95% CI 0.06–0.59) and BCFI (HR 0.19, 95% CI 0.05–0.72) vs T; 7y DFS was 95% vs 83% with CMF→T vs T. Among patients with high MS, CMF→T did not improve DFS (HR 1.27, 95% CI 0.79–2.05) or BCFI (HR 1.37, 95% CI 0.80–2.33) and 7y DFS of 81% for CMF→T and T. Continuous MS was moderately correlated with log Ki67 (r = 0.47) but not correlated with ER or PR. The MS by treatment interaction remained significant with Ki67 in the model.

Conclusions: Low MS was associated with differential benefit favoring those women receiving CMF→T vs T alone for both DFS and BCFI in the first 7 years. The effect was independent of traditional risk factors including Ki67. Hence this study, which is unconfounded by chemotherapy-induced ovarian ablation in younger women, identifies a subset of postmenopausal women with ER+, HER2− tumors that benefit from CMF chemotherapy. This seemingly incongruous observation is consistent with a) the prior observation that only the low-proliferation subgroup by PAM50 11-gene signature benefits from the addition of weekly paclitaxel to adjuvant FEC (GEICAM/9906), b) the ability of MS to identify a subset of women with tumors with disseminated luminal progenitor cells activated through the agonistic activity of tamoxifen, and c) the repetitive dosing of cyclophosphamide and taxol being hypothesized to act via tumor stroma/anti-angiogenesis. The relative contribution of these factors is under investigation.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-03.

P3-01-04: Differential Impact of Gefitinib and PLX4720 on Proliferation of MCF10A and Isogenic Lines as Measured with a Metastasis Expression Score

Background: We previously reported that a published “Metastasis Score” (MS) could be used to evaluate the effects of a PI3K inhibitor (GDC-0941) on mutated human isogenic breast cancer cell lines. MS, based on the expression of14 genes, has been shown to predict distant metastasis in ER(+), node (−), breast cancer. We were interested to determine the impact of gefitinib (EGFR inhibitor) and PLX-4720 (selective inhibitor of BRAF V600E) on MS to assess the applicability of this score to a broader class of targeted agents. In addition, given the cross-talk between metabolism and proliferation, we also profiled genes involved in glycolysis, fatty acid metabolism and oxidative phosphorylation.

Methods: Parental MCF10A (WT for all genes) and isogenic lines of MCF10A harboring PI3K (H1047R), p53 null or KRAS(G12V) mutations were cultured overnight in DMEM:F12 media under identical conditions. Cells were then treated with gefitinib, PLX4720, or DMSO (vehicle control) and further incubated for 24hr. Expression analysis was performed by RT-PCR.

Results: The MS of the PI3K (H1047R) and p53 null lines was higher than the parental line and lower for the KRAS (G12V) line. Treatment of parental, PI3K and KRAS cell lines with gefitinib resulted in dose-dependent decreases in MS, as reported for GDC-0941, with a higher dose required to inhibit growth of PI3K (H1047R) cells. Treatment of p53 null cells with gefitinib, however, had only a modest effect on MS. In contrast to gefitinib, MS increased with PLX-4720 treatment in all 4 lines; the greatest increase was observed in KRAS (G12V) cells. The expression of metabolic genes differed significantly depending on the oncogenic mutation harbored by the cell line. ACTA2, ACLY, RPIA, KHK, GLS2 were most highly expressed in p53 null but lowest in KRAS (G12V), while GLUT5, PFKFB4, ENO3, SLC27A1, PGK2, GLUT1, TKT were expressed most highly in KRAS (G12V) but lowest in PI3K(H1047R). Upon treatment with gefitinib or PLX-4720, genes that were downregulated in the mutated lines generally showed a dose-dependent increase; those that were upregulated relative to the parental, showed a dose-dependent decrease with treatment.

Discussion: The decrease in MS of the parental, PI3K (H1047R) and KRAS (G12V) cell lines treated with gefitinib supports the impact of this EGFR inhibitor on cell proliferation. The modest effect on MS in p53 null cells supports the findings that sensitivity to gefitinib requires active p53 in order to induce apoptosis through a p53-dependent pathway. Increases in MS were observed in all 4 cell lines treated with PLX-4720, with the largest increase observed in KRAS (G12V). The enhanced proliferation of a BRAF WT cell line with a KRAS mutation is consistent with the Ras-dependent nature of this pathway. The metabolic genes showed diverse expression patterns that differed with different oncogenic mutations and likely reflect the multiple mechanisms controlling metabolism in cancer. An improved understanding of the expression of metabolic genes relative to proliferation in cell lines with various oncogenic mutations may provide additional insights into the dysregulation of these cellular processes and the possible role of anti-metabolite intervention.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-01-04.

Radiotherapy for pain

Radiotherapy has been proven to be an effective treatment for the palliation of symptomatic bone metastases. Despite its widespread use and long history, there remains considerable debate over whether a single 8 Gy fraction or multiple fraction schemes are more effective at alleviating bone pain. Recent meta-analyses have shown equal efficacy between the different treatment regimens. One of the reasons supporting multiple fraction use is a lower re-irradiation rate. Recent research has explored many issues associated with retreatment, including timing, appropriate patient selection and concerns of toxicities. However, there are notable side-effects due to radiotherapy, perhaps one of the most significant being 'pain flare', which is a temporary increase in bone pain immediately after treatment. It has a reported incidence of up to 44% in patients. Despite possible side-effects like 'pain flare', radiotherapy can improve pain and also quality of life for patients. One of the quality of life tools that has become useful for assessing the effectiveness of palliative radiotherapy on physical, psychosocial and functional issues is the EORTC-QLQ-BM22. In addition to tracking quality of life changes in patients, analysing symptom clusters can be used to better understand the symptomatology of advanced cancer, and how radiotherapy can affect pain and other symptoms that cancer patients commonly experience.

Abstract P2-09-19: Expression Profiling of a Metastasis Score and a “Glycolytic Index” in Genetically-Defined Human Breast Isogenic Cell Lines Treated with a PI3K Inhibitor

Background: Activation of signaling pathways, loss of tumor suppressors and oncogenic mutations often lead to dysregulation of glycolysis and tumorigenesis. We performed expression analysis on genetically-defined human isogenic breast cancer cell lines and with PI3K inhibitor exposure to determine impact on a patient-relevant Metastasis Score (MS) (proliferation index) and an assembled “glycolytic index”. A better understanding of the links between cellular metabolism and proliferation may yield insights into tumor cell biology and shed light on potential companion diagnostic and therapeutic opportunities.

Methods: A parental MCF10A and three isogenic cell lines harboring K-ras (G12V), PI3Kα (H1047R), and p53 null were grown overnight in the presence of high levels of growth factors in tissue culture flasks. The parental and PI3Kα cells were treated with 0.3 µM, 1 µM,3 µM GDC-0941 or DMSO. All cell lines were incubated for an additional 24 hr. RNA was extracted with RNeasy (Qiagen) and expression analysis performed by RT-PCR. A total of 28 genes were profiled that included 14 genes in a metastasis score (MS) (Tutt et al), 11 glycolysis-associated genes and 3 reference genes. Expression of each gene was calculated using the ΔΔCT method and “summed” with equal weighting to yield an MS and a “glycolytic index”.

Results: The MS and phenotypes for the four untreated cell lines were similar under the monolayer culture conditions used. The parental and PI3Kα cells had a similar “glycolytic index” while p53 null and K-ras cells had elevated indices. Treatment of the parental and PI3Kα with GDC-0941, a PI3K inhibitor, showed a dose-dependent decrease in the expression of constituent MS genes and the glycolytic genes as well as the combined scores. The correlation coefficient between MS and the glycolytic index was 0.77. The four genes in MS with the greatest dose-dependent decrease in expression (BUB1, CCNB1, MYBL2 and UBE2S) are associated with CDK1, a seminal participant in cell cycle regulation. The two genes from the “glycolytic index” with the greatest decrease, HK and PKM, are directly involved in glycolysis. The effect of GDC-0941, as reflected by MS and the “glycolytic index” was more pronounced in PI3Kα than the parental cells (p-value=0.0005).

Conclusion: The good correlation observed between the MS and “glycolytic index “in the treated cell lines supports an association between proliferation and metabolism upon restriction of cell signal transduction. The dose-dependent expression decreases in the two indices and their constituent genes, suggest that this PI3K inhibitor successfully perturbs both fundamental processes of the cell. Given the ultimate targeting of proliferation suppression, these scores may serve as useful tools in evaluating therapeutic agents, independent of the specific intended pathways. The similar proliferation levels observed in untreated MCF10A and three mutated cell lines suggest either that single oncogenic mutations are insufficient to affect MS or that the in vitro conditions are masking the metastatic/invasive phenotype. Studies are underway to evaluate cells grown in 3D Matrigel that more accurately mimic the tumor microenvironment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-19.

Daily hemodialysis 2006. State of the art

The need to improve the dialysis outcomes, the negative results from the HEMO and ADEMEX studies as well reports of clinical benefits have rekindled the interest in daily hemodialysis. Although no randomized controlled studies have been published, a large number of manuscripts have described significant benefits from both the short or nocturnal forms of daily (quotidian) dialysis or hemo(dia)filtration. They include improved quality of life, hemodynamic stability, blood pressure control with minimal number of medications, anemia control, regression of cardiac hypertrophy and improved nutrition. Furthermore, quotidian nocturnal hemodialysis provides higher dialysis dose, and has been described to improve endothelial as well as endothelial progenitor cell function, heart rate variability, sleep and phosphate control while it offers unrestricted diet. Several studies have pointed to a lower overall cost and improved cost utility when treating patients using quotidian hemodialysis at home. The obstacles to widespread use are the reimbursement structure in most countries, the willingness and ability of the patients to do home hemodialysis and the availability of user-friendly machines. A prospective randomized controlled study sponsored by the National Institutes of Health (NIH) and US Centers for Medicare and Medicaid services (CMS) currently underway will be pivotal in confirming these benefits and convincing the stakeholders to promote the use of daily hemodialysis.

Familial hypercholesterolaemia commonly presents with Achilles tenosynovitis

BACKGROUND

Patients with heterozygous familial hypercholesterolaemia (HeFH) develop tendon xanthomata (TX), most commonly in their Achilles tendons. Even before tendons are chronically enlarged, tenosynovitis may occur and medical advice be sought. Untreated HeFH carries a high risk of premature coronary heart disease, which can be ameliorated by early diagnosis.

OBJECTIVE

To determine the prevalence of episodes of Achilles tendon pain in HeFH before its diagnosis.

METHODS

Patients with definite HeFH (Simon Broome criteria) attending a lipid clinic were identified. They completed a questionnaire asking about symptoms relating to their Achilles tendons. Unaffected spouses or cohabiting partners served as controls.

RESULTS

133 patients (47% men) and 87 controls (51% men) participated. TX had been recognised by the referring physicians in <5% of cases. However, 62 (46.6% (95% confidence interval (CI) 38.1 to 55.1)) patients had experienced one or more episodes of pain in one or both Achilles tendons lasting >3 days, whereas only 6 (6.9% (1.6 to 12.2)) controls had done so (difference p<0.001; likelihood ratio 6.75). Typically, in the patients with HeFH the pain lasted 4 days (median). It was described as severe or very severe in 24/62 (38.7% (30.4 to 47.0)) patients with HeFH, but never more than moderate in controls. 35 (26.3% (18.8 to 33.8)) patients with HeFH had consulted a doctor about Achilles tendon pain, but in no case had this led to a diagnosis of HeFH. None of the controls had consulted a doctor.

CONCLUSIONS

Measurement of serum cholesterol in patients presenting with painful Achilles tendon could lead to early diagnosis of HeFH.

Ethnic trends in lipid tests in general practice

BACKGROUND

South Asian migrants have a higher cardiovascular mortality than the indigenous population. Contributory factors may include a lower rate of cardiovascular risk assessment uptake and compliance.

AIM

To compare rates of lipid testing, follow-up and patterns of dyslipidaemia in South Asian and non-South-Asian populations in Manchester.

DESIGN

Retrospective cross-sectional survey.

METHODS

Lipid requests from 14 general practices were analysed, using name recognition software to assign ethnicity.

RESULTS

Compared with non-South-Asians, the age-standardized rate of lipid testing in South Asians was similar in men at 12.1% (95%CI 11.6-12.6) vs. 11.2% (9.5-13.0), but higher in women at 18.6% (15.9-21.2) vs. 13.2% (12.6-13.7). Trends of cholesterol with repeat testing were similar in the two populations. However, South Asian women had lower mean levels of total cholesterol (5.50 vs. 5.68 mmol/l, p = 0.021), lower levels of HDL (1.20 vs. 1.46 mmol/l, p < 0.001), an excess of hypertriglyceridaemia (1.62 vs. 1.45 mmol/l, p = 0.035) and a greater proportion with cholesterol > 5.2 mmol/l combined with low HDL (43.1% vs. 20.2%, p = 0.002). South Asian men had lower levels of total cholesterol (5.17 vs. 5.37 mmol/l, p = 0.048) and lower levels of HDL (1.07 vs. 1.64 mmol/l, p < 0.001). There was no difference in the proportion of South Asians men and women with cholesterol < 5.2 mmol/l combined with low HDL.

DISCUSSION

The rate of lipid testing and change in cholesterol levels with repeated testing did not differ between South Asian and non-South-Asian groups. The pattern of dyslipidaemia seen in this South Asian population, especially women, was different from that of the non-South-Asian population, with possible implications for cardiovascular risk assessment.

Preventing cardiovascular disease in hypertension: effects of lowering blood pressure and cholesterol

BACKGROUND

In guidelines for the primary prevention of cardiovascular disease, systolic blood pressure (SBP) or diastolic blood pressure (DBP) is treated with medication at lower levels of risk than those at which statin treatment is recommended for cholesterol lowering.

AIM

To compare the potential benefits of antihypertensive medication and statin therapy in hypertensive patients, and examine whether this policy is rational.

DESIGN

Retrospective cross-sectional survey.

METHODS

We studied 146 men and 150 women aged 56 (54-58) (mean (95% CI)) years and 60 (58-62) years, respectively, who had commenced drug therapy for hypertension within 10 years in five general practices in Greater Manchester. Coronary heart disease (CHD) and stroke risk were calculated, and the potential benefit of blood pressure lowering treatment and statin therapy estimated using the results of published meta-analyses of clinical trials.

RESULTS

Blood pressure before treatment was initiated was 176 (173-179)/102 (100-104) mmHg in men and 176 (172-179)/98 (96-100) mmHg in women. Serum cholesterol was 5.7 (5.5-5.9) mmol/l and high density lipoprotein (HDL) cholesterol 1.3 (1.2-1.4) mmol/l in men. The corresponding values in women were 6.3 (6.1-6.5) mmol/l and 1.5 (1.4-1.6) mmol/l. Of the men, 44% (36-52%) smoked and 23% (17-31%) had diabetes mellitus, whereas 27% (20-35%) of the women smoked and 26% (19-34%) had diabetes. These risk factors gave the combined group of men and women a CHD risk of 19.7% (12.0-28.0%) (median (IQR)) and a stroke risk of 8.8% (3.8-13.9%) over the next 10 years. All patients were prescribed antihypertensive medication and 15% subsequently received statin treatment. The 10-year CHD risk would be expected to decrease to 16.5% (10.1-23.5%) on anti-hypertensive therapy. Had statin treatment been given instead, it would have been reduced to 13.2% (8.05-18.7%). For stroke, the 10-year risk on antihypertensive therapy was calculated as 5.5% (2.4-8.6%) and on statin 6.2% (2.7-9.9%). This meant that combined CHD and stroke risk would be reduced from 29.4% (17.5-41.5%) to 22.4% (17.5-41.5%) on antihypertensive therapy and to 20.1% (11.9-28.2%) on statins. The difference between statin and antihypertensive therapy was statistically significant (p<0.0001).

DISCUSSION

Because the object of drug treatment in mild-moderate hypertension is to reduce cardiovascular disease risk and not simply to decrease blood pressure, current recommendations and practice should be revised so that more patients can benefit from evidence-based therapy favouring a more holistic approach, including cholesterol-lowering therapy.

Costs of aspirin and statins in general practice

BACKGROUND

Aspirin and statins are the two drugs most commonly indicated for secondary prevention of atherosclerotic disease in the UK. Statin treatment, which is more expensive, is under-prescribed.

AIM

To assess the expenditure in Greater Manchester general practices on aspirin and statins.

DESIGN

Survey of general practice records.

METHODS

Practice registers were searched for patients receiving regular prescriptions for aspirin. For each patient, the next patient of the same sex, aged within +/- 5 years, not on aspirin, acted as a control. Details of all medications were recorded. In a sub-study, records of 100 patients on aspirin were studied to determine indications for aspirin prescription.

RESULTS

There were 1003 (511 men, 492 women) in each group; mean age was 70 years in both groups. In the sub-study, 79% of patients received aspirin for established vascular disease, 9% for hypertension, 5% for diabetes mellitus, 5% for unknown reasons and 2% for arthritis. Of the patients on aspirin, 67% received dispersible aspirin 75 mg/day. The rest were on higher doses (10%) or on more expensive preparations (22%), costing up to 22.4 p/day. The mean daily cost of aspirin was 1.7p. Dyspepsia treatment was received by 266 patients and 194 controls (p<0.001). There was a wide range of dyspepsia medications (10-306p/day), averaging in the groups as a whole 15.5p/day in patients and 12.5p/day in controls. Of the patients on aspirin, 28% received statins, compared to 4% of controls. Mean daily expenditure on statins in patients was 23.4p.

CONCLUSION

Assuming the difference in the use of medication for dyspepsia between patients and controls was due to aspirin, the full cost of aspirin treatment was 4.7p/day. Statins were probably under-prescribed in aspirin-takers, many of whom would have been at high CHD risk.

The comparative impact of video-consultation on neurosurgical health services

This study evaluated the impact of telemedicine technology on the provision of neurosurgical health services. We focused on the differences between the use of real time audio-visual teleconferencing and teleradiology versus conventional telephone consultations in the referral of neurosurgical patients from a large district general hospital. All patients requiring emergency neurosurgical consultation were included for randomization into telephone consultation only (Mode A), teleradiology and telephone consultation (Mode B) and video-consultation (Mode C). Measures of effectiveness included diagnostic accuracy and adverse events during the transfer and Glasgow Outcome Score. In a 10-month period, 327 patients were recruited and randomized into the study: the male/female ratio was 2:1 and the number of patients required to be transferred to the neurosurgical unit was 125 (38%). There was a trend towards a more favourable outcome in the video-consultation mode (44%, Mode C), versus teleradiology (31%, Mode B), versus telephone consultation (38%, Mode A). The interim data of this prospective randomized trial suggests that video-consultation may have a favourable impact on emergency neurosurgical consultations.

Plasma viral load in HIV-1 and HIV-2 singly and dually infected individuals in Guinea-Bissau, West Africa: significantly lower plasma virus set point in HIV-2 infection than in HIV-1 infection

BACKGROUND

The intriguing differences in the natural course, transmissibility, and epidemiological characteristics of human immunodeficiency virus type 1 (HIV-1) and HIV-2 are still insufficiently explained. Differences in plasma viral load are an obvious possibility, but this has been difficult to investigate because of the lack of tests for HIV-2 RNA.

OBJECTIVE

To compare plasma HIV RNA load between individuals infected with HIV-1 and HIV-2 in Guinea-Bissau, a West African country with high prevalence and incidence of HIV-1 and HIV-2 infection.

METHODS

A total of 102 participants were recruited from ongoing prospective cohort studies. These included 19 HIV-1 and 29 HIV-2 seroincident cases tested at a median of less than 2 years after seroconversion as well as seroprevalent cases with single (9 HIV-1 cases and 31 HIV-2 cases) or dual (n = 14) infections. Plasma HIV RNA levels were determined by a commercial HIV-1 assay and an experimental HIV-2 assay based on the same principles.

RESULTS

The viral set point, ie, the semi-equilibrium reached after seronconversion, was 28-fold lower in recent HIV-2 seroconverters than in recent HIV-1 seroconverters (median, 2500 and 70,000 RNA copies per milliliter, respectively; P<. 001). This difference appeared to persist to symptomatic stages of the diseases. Dually infected individuals had lower plasma HIV-1 RNA levels than singly infected individuals.

CONCLUSIONS

The differences between HIV-1 and HIV-2 infection are likely to be caused by differences in plasma viral set point and load, but the mechanisms through which HIV-2 infection is contained to a higher degree than HIV-1 remain to be identified. Arch Intern Med. 2000;160:3286-3293.

Dissociation of immunologic and virologic responses to highly active antiretroviral therapy

OBJECTIVE

Immunologic markers, levels of HIV DNA, and infectious HIV were compared in partial responders (PR) to HAART who had high plasma HIV RNA levels but stable or increasing levels of CD4+ peripheral blood mononuclear cells (PBMC), and patients with complete failure (CF) who had very low or decreasing levels of CD4+ PBMC and high plasma HIV RNA levels.

DESIGN AND METHODS

CD4 and CD8 levels were monitored by flow cytometry. Beta2-microglobulin (beta2M) and neopterin levels were measured by quantitative enzyme immunoassays. Plasma and PBMC from 11 PR and 13 CF were analyzed for infectious HIV levels in limiting dilution cultures. Polymerase chain reaction (PCR) assays were used to quantify cellular HIV DNA and plasma HIV RNA.

RESULTS

In comparison with CF, PR had little or no CD4+ cell loss, a substantial increase in CD8+ cells, significantly fewer positive plasma HIV cultures (p = .03), lower frequencies of infectious HIV in total PBMC (p = .005) and in CD4+ PBMC (p < .001), and lower frequencies of HIV DNA in CD4+ PBMC (p = .007).

CONCLUSIONS

Lower levels of infectious HIV and a lower frequency of CD4+ PBMC that contain "productive" HIV DNA in PR as compared with CF may contribute to the stable or increasing CD4+ PBMC levels of the PR. However, HAART may also have effects on lymphocyte homeostasis independent of its antiviral activity.

Laboratory markers of antiviral activity

Quantitative assays for viral nucleic acids have been instrumental in monitoring the response of patients to various antiviral therapies. The level of viraemia is predictive of clinical outcome in that a reduced risk of progression to AIDS or death was observed with lower plasma human immunodeficiency virus (HIV) RNA levels. Rebound in viral levels often signals therapeutic failures, some of which are associated with the development of drug resistance. Quantitative plasma assays for HIV, hepatitis C virus (HCV), cytomegalovirus (CMV) and hepatitis B virus (HBV) have been developed. Over time, modifications to these assays have been required to meet new demands. For example, as antiviral therapies have become more effective, HIV and HCV assays of greater sensitivity are required in order to follow patients for longer periods of time and to fully assess the extent of viral suppression. For HIV-1, a large percentage of patients treated with combination therapies had viral loads that were below the detection limit of the ultrasensitive assay (50 copies/ml). To assess the residual viral burden in this patient population an assay to quantify HIV-1 proviral DNA in peripheral blood mononuclear cells was developed. Studies to date indicate that proviral DNA remains easily detectable despite undetectable plasma RNA and may be useful in monitoring this patient population. To increase assay throughput, a new generation of quantitative assays that will provide real-time detection and a 6 log10 detection range from a single amplification is under development.

Effect of influenza vaccination on viral replication and immune response in persons infected with human immunodeficiency virus receiving potent antiretroviral therapy

Nineteen patients infected with human immunodeficiency virus (HIV) with varying levels of viral suppression achieved with antiretroviral therapy were evaluated to determine whether trivalent influenza vaccine activated HIV replication. Humoral immune responses and CD4+ lymphocyte subsets were compared in 5 HIV-uninfected vaccinated subjects. Transient elevations of plasma HIV RNA levels (76-89 copies/mL) appeared within 2 weeks in 3 of 11 patients with <50 copies/mL at baseline. Sustained elevation in HIV plasma RNA was observed in 7 of 8 patients with baseline HIV RNA of >50 copies/mL. HIV DNA decreased in patients with <400 RNA copies/mL at baseline and showed an HIV RNA increase after vaccination (n=8) when compared with 8 patients with <50 copies/mL at baseline who lacked viral response to vaccination. Concurrent decreases in proviral DNA and memory phenotype CD4+ cells in association with increased plasma HIV RNA after vaccination in patients with <400 RNA copies/mL at baseline suggest that in vivo mobilization of the latently infected cell reservoir may occur during potent antiretroviral therapy.

PCR-Based assay to quantify human immunodeficiency virus type 1 DNA in peripheral blood mononuclear cells

An assay that quantifies the amount of human immunodeficiency virus type 1 (HIV-1) DNA in peripheral blood mononuclear cells has been developed. PCR amplification of the HIV-1 DNA is performed in the presence of an internal quantitation standard, and colorimetric detection of the amplified product is performed with microwell plates. The copies of HIV-1 DNA are normalized to total genomic DNA input. The assay has an analytical sensitivity of 10 input copies per amplification reaction and a three-log detection range. In an analysis of sequential samples from patients on combination therapy, HIV-1 DNA was quantifiable for all individuals tested, including those with undetectable plasma HIV-1 RNA. In a separate study, a comparison of HIV-1 DNA levels was made with a group of long-term survivors and progressors. The mean HIV-1 DNA levels were lower in the long-term survivors than in the progressors (P, 0.04). The mean HIV-1 RNA levels were also lower, but the difference was not statistically significant (P, 0.164). A quantitative DNA assay will provide an additional tool to gain insight into the natural history of infection and the continued efficacy of potent antiretroviral therapies.

Suppression of lymphocyte mitogenesis by tamoxifen: studies on protein kinase C, calmodulin and calcium

The effect of tamoxifen (TX; 1.0 microM) on the mitogenic response of rat lymphocytes was compared with the effect of drugs that are known to act on protein kinase C (PKC), calmodulin (CM), and calcium (Ca(2+)). The calcium ionophore A23187 (0.2 microM) was mitogenic on its own which was not influenced by TX. The agents modulating PKC or CM (phorbol-myristate-13-acetate; R24571, chlorpromazine) influenced mitogenesis differently than did TX. General inhibition of lymphocyte proliferation was seen with the Ca(2+) antagonist agents (EGTA, TMB-8) as with TX. The antiproliferative effect of TX was partially reversed by the increase of Ca(2+) in the culture medium when T cell mitogens were used, but not in the case of lipid A, a B lymphocyte mitogen. However, the concanavalin A-induced Ca(2+) influx was further elevated by TX which differed from the effect of the Ca(2+) channel-blocking agent verapamil. The results suggest that TX resets the threshold stimulus necessary for mitogenesis and is completely reversible.

HIV mediates a productive infection of the brain

BACKGROUND

Approximately one quarter of patients with AIDS develop severe cognitive deficits called HIV-associated dementia complex. There is some controversy regarding the importance of viral load and distribution in mediating this neurologic disease.

OBJECTIVE

Brain HIV proviral and RNA loads were compared to define the molecular nature of HIV infection of the brain.

METHOD

Neuropathologic examination was performed on brains from 10 autopsies of patients with AIDS that had short post-mortem intervals and no evidence of opportunistic infection. Viral DNA and RNA were extracted and quantified from multiple brain regions. These findings were compared with triple-label immunofluorescence for viral and cell markers.

RESULTS

Brains with histopathologic evidence of HIV encephalitis contained abundant HIV RNA and DNA. Regions without productive HIV infection showed minimal proviral load. By immunocytochemistry, only brain macrophages/microglia double labeled for viral proteins.

CONCLUSIONS

HIV mediates a productive infection of brain macrophages/microglia. There was no evidence supporting the hypothesis of substantial neuronal or macroglial infection, or evidence of substantial proviral burden prior to the development of productive infection.

Arabidopsis cop8 and fus4 mutations define the same gene that encodes subunit 4 of the COP9 signalosome

The pleiotropic constitutive photomorphogenic/deetiolated/fusca (cop/det/fus) mutants of Arabidopsis exhibit features of light-grown seedlings when grown in the dark. Cloning and biochemical analysis of COP9 have revealed that it is a component of a multiprotein complex, the COP9 signalosome (previously known as the COP9 complex). Here, we compare the immunoaffinity and the biochemical purification of the COP9 signalosome from cauliflower and confirm its eight-subunit composition. Molecular cloning of subunit 4 of the complex revealed that it is a proteasome-COP9 complex-eIF3 domain protein encoded by a gene that maps to chromosome 5, near the chromosomal location of the cop8 and fus4 mutations. Genetic complementation tests showed that the cop8 and fus4 mutations define the same locus, now designated as COP8. Molecular analysis of the subunit 4-encoding gene in both cop8 and fus4 mutants identified specific molecular lesions, and overexpression of the subunit 4 cDNA in a cop8 mutant background resulted in complete rescue of the mutant phenotype. Thus, we conclude that COP8 encodes subunit 4 of the COP9 signalosome. Examination of possible molecular interactions by using the yeast two-hybrid assay indicated that COP8 is capable of strong self-association as well as interaction with COP9, FUS6/COP11, FUS5, and Arabidopsis JAB1 homolog 1, the latter four proteins being previously defined subunits of the Arabidopsis COP9 signalosome. A comparative sequence analysis indicated that COP8 is highly conserved among multicellular eukaryotes and is also similar to a subunit of the 19S regulatory particle of the 26S proteasome.

Human immunodeficiency virus type 1-specific cytotoxic T lymphocyte activity is inversely correlated with HIV type 1 viral load in HIV type 1-infected long-term survivors

HIV-1-specific cytotoxic T cell (CTL) activity has been suggested to correlate with protection from progression to AIDS. We have examined the relationship between HIV-specific CTL activity and maintenance of peripheral blood CD4+ T lymphocyte counts and control of viral load in 17 long-term survivors (LTSs) of HIV-1 infection. Longitudinal analysis indicated that the LTS cohort demonstrated a decreased rate of CD4+ T cell loss (18 cells/mm3/year) compared with typical normal progressors (approximately 60 cells/mm3/year). The majority of the LTSs had detectable, variable, and in some individuals, quite high (>10(4) RNA copies/ml) plasma viral load during the study period. In a cross-sectional analysis, HIV-specific CTL activity to HIV Gag, Pol, and Env proteins was detectable in all 17 LTSs. Simultaneous analysis of HIV-1 Gag-Pol, and Env-specific CTLs and virus load in protease inhibitor-naive individuals showed a significant inverse correlation between Pol-specific CTL activity and plasma HIV-1 RNA levels (p = 0.001). Furthermore, using a mixed linear effects model the combined effects of HIV-1 Pol- and Env-specific CTL activity on the viral load were significantly stronger than the effects of HIV-1 Pol-specific CTL activity alone on predicted virus load. These data suggest that the presence of HIV-1-specific CTL activity in HIV-1-infected long-term survivors is an important component in the effective control of HIV-1 replication.

Development of calibrated viral load standards for group M subtypes of human immunodeficiency virus type 1 and performance of an improved AMPLICOR HIV-1 MONITOR test with isolates of diverse subtypes

Accurate determination of plasma human immunodeficiency virus type 1 (HIV-1) RNA levels is critical for the effective management of HIV-1 disease. The AMPLICOR HIV-1 MONITOR Test, a reverse transcription-PCR-based test for quantification of HIV-1 RNA in plasma, was developed when little sequence information on HIV-1 isolates from outside North America was available. It has since become apparent that many non-subtype B isolates, particularly subtypes A and E, are detected inefficiently by the test. We describe here the AMPLICOR HIV-1 MONITOR Test, version 1.5, an upgraded test developed to minimize subtype-related variation. We also developed a panel of HIV-1 standards containing 30 HIV-1 isolates of subtypes A through G. The virus particle concentration of each cultured viral stock was standardized by electron microscopic virus particle counting. We used this panel to determine the performance of the original AMPLICOR HIV-1 MONITOR Test and version 1.5 of the test with HIV-1 subtypes A through G. The original test underestimated the concentration of HIV-1 subtype A, E, F, and G RNA by 10-fold or more, whereas version of the 1.5 test yielded equivalent quantification of HIV-1 RNA regardless of the subtype. In light of the increasing intermixing of HIV-1 subtypes worldwide, standardization of PCR-based tests against well-characterized viral isolates representing the full range of HIV-1 diversity will be essential for the continued utility of these important clinical management tools.

The Arabidopsis homologue of an eIF3 complex subunit associates with the COP9 complex

The Arabidopsis COP9 complex is a multi-subunit repressor of photomorphogenesis which is conserved among multicellular organisms. Approximately 12 proteins copurify with the COP9 complex. Seven of these proteins are orthologues of subunits of the recently published mammalian COP9 complex. Four of the proteins show amino acid similarity to various subunits of the COP9 complex, eIF3 complex and 19S cap of the proteasome. We have studied one of these proteins in order to determine if it is a component of the COP9 complex. Arabidopsis p105 is highly similar to the p110 subunit of the human elF3. The p105 gene is induced during photomorphogenesis, and RNA and protein analysis reveal different tissue accumulation patterns. p105 is found in a large protein complex. p105 interacts in yeast with both COP9 and FUS6, two known components of the COP9 complex. Our results indicate that p105 is not a component of the COP9 core complex, though it may interact with components of the complex.

Early prognostic indicators in primary perinatal human immunodeficiency virus type 1 infection: importance of viral RNA and the timing of transmission on long-term outcome

The time of perinatal human immunodeficiency virus type 1 (HIV-1) transmission and the pattern of early plasma viremia as predictors of disease progression were evaluated in infected infants followed from birth. Cox proportional hazards modeling demonstrated that a 1-log higher HIV-1 RNA copy number at birth was associated with a 40% increase in the relative hazard (RH) of developing CDC class A or B symptoms (P = .004), a 60% increase in developing AIDS (P = .01), and an 80% increase in the of risk death (P = .023) over the follow-up period of up to 8 years. The peak HIV-1 RNA copy number for infants during primary viremia was also predictive of progression to AIDS (RH, 9.9; 95% confidence interval [95% CI], 1.8-54.1; P = .008) and death (RH, 6.9; 95% CI, 1.1-43.8; P = .04). The results indicate that high levels of HIV-1 RNA at birth and during primary viremia are associated with early onset of symptoms and rapid disease progression to AIDS and death in perinatally infected children.

Reduction of HIV-1 in blood and lymph nodes following potent antiretroviral therapy and the virologic correlates of treatment failure

Potent antiretroviral therapy can reduce plasma HIV RNA levels below the threshold of detection for periods of a year or more. The magnitude of HIV RNA reduction in the lymphoid tissue in patients with suppression of HIV RNA levels in plasma beyond 6 months has not been determined. We evaluated levels of HIV RNA and DNA and characterized resistance mutations in blood and inguinal lymph node biopsies obtained from 10 HIV-infected subjects who received 36-52 weeks of indinavir (IDV)/zidovudine (ZDV)/lamivudine (3TC), IDV, or ZDV/3TC. After 1 year of therapy, viral RNA levels in LN of individuals remained detectable but were log10 = 4 lower than in subjects on the triple drug regimen with interruption of therapy or in those treated with ZDV/3TC alone, who had viral loads in their lymph nodes indistinguishable from those expected for untreated patients. In all cases viral DNA remained detectable in lymph nodes and peripheral blood mononuclear cells (PBMC). When plasma virus suppression was incomplete, lymph node and PBMC cultures were positive and drug resistance developed. These studies indicate that pronounced and sustained suppression of plasma viremia by a potent antiretroviral combination is associated with low HIV RNA levels in the lymph nodes 1 year after treatment. Conversely, the persistence of even modest levels of plasma virus after 1 year of treatment reflects ongoing viral replication, the emergence of drug resistance, and the maintenance of high burdens of virus in the lymph nodes.

Dietary regulation of the very low density lipoprotein receptor in mouse heart and fat

The very low density lipoprotein (VLDL) receptor is a member of the LDL receptor family. As opposed to the LDL receptor, the VLDL receptor is expressed primarily in muscle and adipose tissue. Although the VLDL receptor is capable of binding lipoproteins, its functional role is still unclear. Previous studies found that VLDL receptor expression is unaffected by fasting in the rat. The current studies examined whether VLDL receptor expression is altered with fasting in the mouse. Balb/c mice were fasted for periods up to 48 hours, killed, hearts and epididymal fat obtained, and total membranes prepared. To detect the VLDL receptor a portion of the rat VLDL receptor was expressed as a bacterial fusion protein, purified and used to immunize rabbits. The antibodies raised specifically recognized intact VLDL receptor. When cardiac membranes were immunoblotted, VLDL receptor expression increased progressively with fasting, doubling at 36 hours. In contrast, VLDL receptor expression decreased progressively with fasting in membranes from epididymal fat, being reduced 70% by 48 hours. Thus, VLDL receptor expression appears to be regulated in mouse heart and fat by nutritional perturbation, supporting a potential role for the VLDL receptor in the delivery of triglycerides/fatty acids as fuel.

A rapid and simple method for extracting human immunodeficiency virus type 1 RNA from plasma: enhanced sensitivity

We present here a rapid and simple technique for processing human immunodeficiency virus (HIV)-infected plasma by high-speed centrifugation. HIV type 1 virions are pelleted from up to 1 ml of plasma, gently lysed with a nonionic detergent, and directly amplified. The procedure has few manipulations and requires approximately 1.5 h for the processing of 24 samples. Viral recovery ranges from 80 to 90%, with an analytical sensitivity approaching 20 copies/ml.