Ultrasensitive Quantitation of Human Immunodeficiency Virus Type 1 RNA in Plasma by the AMPLICOR and COBAS AMPLICOR HIV-1 MONITOR™ Tests

The measurement of plasma human immunodeficiency virus type 1 (HIV-1) RNA levels has become an important tool for identifying individuals likely to benefit from antiretroviral therapy (1-7) as well as monitoring patients on therapy (8-14), and is now regarded as standard medical practice for managing the treatment of HIV-1-infected individuals (15-21). Three commercially available assays for measuring HIV-1 RNA levels are available. The firstgeneration AMPLICOR HIV-1 MONITOR™ Test, which uses reverse transcriptase-polymerase chain reaction (RT-PCR) technology, has a lower limit of quantitation of 400 copies/mL of plasma (22,23). The NucliSens HIV-1 QT Test (Organon Teknika, Boxtel, Netherlands), a second-generation assay based on the nucleic acid sequence-based amplification technique, has a lower limit of quantitation of 100 HIV-1 RNA copies/mL of plasma (24). The Quantiplex HIV-1 Version 2.0 Test (Chiron, Emeryville, CA), which uses the branched-chain DNA signal amplification technique, has a lower limit of quantitation of 500 HIV-1 RNA copies/mL of plasma (25,26).

Estimating the prevalence of anaemia: a comparison of three methods

OBJECTIVE

To determine the most effective method for analysing haemoglobin concentrations in large surveys in remote areas, and to compare two methods (indirect cyanmethaemoglobin and HemoCue) with the conventional method (direct cyanmethaemoglobin).

METHODS

Samples of venous and capillary blood from 121 mothers in Indonesia were compared using all three methods.

FINDINGS

When the indirect cyanmethaemoglobin method was used the prevalence of anaemia was 31-38%. When the direct cyanmethaemoglobin or HemoCue method was used the prevalence was 14-18%. Indirect measurement of cyanmethaemoglobin had the highest coefficient of variation and the largest standard deviation of the difference between the first and second assessment of the same blood sample (10-12 g/l indirect measurement vs 4 g/l direct measurement). In comparison with direct cyanmethaemoglobin measurement of venous blood, HemoCue had the highest sensitivity (82.4%) and specificity (94.2%) when used for venous blood.

CONCLUSIONS

Where field conditions and local resources allow it, haemoglobin concentration should be assessed with the direct cyanmethaemoglobin method, the gold standard. However, the HemoCue method can be used for surveys involving different laboratories or which are conducted in relatively remote areas. In very hot and humid climates, HemoCue microcuvettes should be discarded if not used within a few days of opening the container containing the cuvettes.

Exercise treatment for major depression: maintenance of therapeutic benefit at 10 months

OBJECTIVE

The purpose of this study was to assess the status of 156 adult volunteers with major depressive disorder (MDD) 6 months after completion of a study in which they were randomly assigned to a 4-month course of aerobic exercise, sertraline therapy, or a combination of exercise and sertraline.

METHODS

The presence and severity of depression were assessed by clinical interview using the Diagnostic Interview Schedule and the Hamilton Rating Scale for Depression (HRSD) and by self-report using the Beck Depression Inventory. Assessments were performed at baseline, after 4 months of treatment, and 6 months after treatment was concluded (ie, after 10 months).

RESULTS

After 4 months patients in all three groups exhibited significant improvement; the proportion of remitted participants (ie, those who no longer met diagnostic criteria for MDD and had an HRSD score <8) was comparable across the three treatment conditions. After 10 months, however, remitted subjects in the exercise group had significantly lower relapse rates (p = .01) than subjects in the medication group. Exercising on one's own during the follow-up period was associated with a reduced probability of depression diagnosis at the end of that period (odds ratio = 0.49, p = .0009).

CONCLUSIONS

Among individuals with MDD, exercise therapy is feasible and is associated with significant therapeutic benefit, especially if exercise is continued over time.

Comparison of two amplification technologies for detection and quantitation of human immunodeficiency virus type 1 RNA in the female genital tract. Division of AIDS Treatment Research Initiative 009 Study Team

Human immunodeficiency virus type 1 (HIV-1) RNA levels in female genital tract and peripheral blood samples were compared using two commercial amplification technologies: the Roche AMPLICOR HIV-1 MONITOR test and either the Organon Teknika nucleic acid sequence-based amplification (NASBA-QT) assay or the NucliSens assay. Estimates of HIV-1 RNA copy number were derived from internal kit standards and analyzed unadjusted and adjusted to a common set of external standards. We found a discordance rate of approximately 18% between the two technologies for the detection of HIV-1 in either the genital tract or peripheral blood samples. Detection discordance was not consistent among specimens or among women. There were no significant differences in adjusted or unadjusted estimates of HIV-1 RNA copy number in the genital tract samples using the AMPLICOR HIV-1 MONITOR test and either the NASBA-QT assay or the NucliSens assay. In addition, the estimated HIV-1 RNA copy number in peripheral blood samples did not differ when tested with the NucliSens assay and the AMPLICOR HIV-1 MONITOR test using kit standards. However, there was a significant difference in estimated RNA copy number between the NASBA-QT assay and the AMPLICOR HIV-1 MONITOR test for internal kit standards, which, as we have previously shown, was eliminated after adjustment with the external standards. Our results suggest that the Roche and Organon Teknika assays are equivalent for quantifying HIV-1 RNA in female genital tract specimens, although variation in detection does exist.

Anti-angiogenic cues from vascular basement membrane collagen

Vascular basement membrane is an important structural component of blood vessels and has been shown to interact with and modulate vascular endothelial behavior during angiogenesis. During the inductive phase of tumor angiogenesis, this membrane undergoes many degradative and structural changes and reorganizes to a native state around newly formed capillaries in the resolution phase. Such matrix changes are potentially associated with molecular modifications that include expression of matrix gene products coupled with conformational changes, which expose cryptic protein modules for interaction with the vascular endothelium. We speculate that these interactions provide important endogenous angiogenic and anti-angiogenic cues. In this report, we identify an important antiangiogenic vascular basement membrane-associated protein, the 26-kDa NC1 domain of the alpha1 chain of type IV collagen, termed arresten. Arresten was isolated from human placenta and produced as a recombinant molecule in Escherichia coli and 293 embryonic kidney cells. We demonstrate that arresten functions as an anti-angiogenic molecule by inhibiting endothelial cell proliferation, migration, tube formation, and Matrigel neovascularization. Arresten inhibits the growth of two human xenograft tumors in nude mice and the development of tumor metastases. Additionally, we show that the anti-angiogenic activity of arresten is potentially mediated via mechanisms involving cell surface proteoglycans and the alpha1beta1 integrin on endothelial cells. Collectively, our results suggest that arresten is a potent inhibitor of angiogenesis with a potential for therapeutic use.

Extensive metallosis and necrosis in failed prostheses with cemented titanium-alloy stems and ceramic heads

We describe three prostheses with cemented titanium-alloy stems and Al2O3 ceramic femoral heads which had to be revised after a mean period of implantation of 78 months. In each case, the neck of the prosthesis had been so severely worn that the profile was elliptical rather than circular. There was severe metallosis of the periprosthetic tissues. Metal particles isolated from the tissues were approximately one nanometre in size and the ratios of titanium, aluminium and vanadium in the particles were the same as in the original alloy. Histologically, the high concentration of metal particles masked the presence of high-density polyethylene (HDP) debris, but again particles about one nanometre in size were isolated from the tissues. The severe necrobiosis and necrosis noted were consistent with other reports of the presence of extensive wear particles in periprosthetic tissues. Wear is presumed to have occurred as a result of mismatch between the shape or size of the taper cone and the femoral head, or to changes in the geometry of loading due to migration of the cup. To facilitate early intervention, patients with this design of prosthesis should be monitored radiologically.

Extensive metallosis and necrosis in failed prostheses with cemented titanium-alloy stems and ceramic heads

We describe three prostheses with cemented titanium-alloy stems and Al2O3 ceramic femoral heads which had to be revised after a mean period of implantation of 78 months. In each case, the neck of the prosthesis had been so severely worn that the profile was elliptical rather than circular. There was severe metallosis of the periprosthetic tissues. Metal particles isolated from the tissues were approximately one nanometre in size and the ratios of titanium, aluminium and vanadium in the particles were the same as in the original alloy. Histologically, the high concentration of metal particles masked the presence of high-density polyethylene (HDP) debris, but again particles about one nanometre in size were isolated from the tissues. The severe necrobiosis and necrosis noted were consistent with other reports of the presence of extensive wear particles in periprosthetic tissues. Wear is presumed to have occurred as a result of mismatch between the shape or size of the taper cone and the femoral head, or to changes in the geometry of loading due to migration of the cup. To facilitate early intervention, patients with this design of prosthesis should be monitored radiologically.

Fat intake and breast cancer risk in an area where fat intake is low: a case-control study in Indonesia

BACKGROUND

Associations of fat and other macronutrients with breast cancer risk are not clear in areas where fat intake is low.

METHODS

We conducted a hospital-based case-control study from 1992 to 1995 in Jakarta, Indonesia.

RESULTS

The study, based on 226 cases and 452 age and socioeconomic status matched controls, provided the following findings. (a) In the pre-marriage period, the greater the fat or protein consumption, the larger the risk, whereas decreasing risk with increasing carbohydrate intake was detected. The odds ratio (OR) for the highest quartile of intake relative to the lowest was 8.47 (95% CI: 4.03-17.8) for fat, 2.19 (95% CI: 1.30-3.69) for protein, and 0.16 (95% CI: 0.08-0.31) for carbohydrate. A positive association with fat and a negative one with carbohydrate were also observed for the post-marriage period, but of weaker magnitude compared to the pre-marriage period. (b) The effects of macronutrient intakes were stronger among premenopausal than among postmenopausal women. (c) Most of the associations of protein and carbohydrate were insignificant after adjustment for fat intake.

CONCLUSIONS

These findings suggest that fat intake might be an important determinant of breast cancer among populations with a low fat diet in Indonesia.

Stability of plasma human immunodeficiency virus load in VACUTAINER PPT plasma preparation tubes during overnight shipment

VACUTAINER PPT plasma preparation tubes were evaluated to determine the effects of various handling and shipping conditions on plasma human immunodeficiency virus (HIV) load determinations. Plasmas obtained from PPT tubes stored and shipped under nine different conditions were compared to conventional EDTA tube plasmas stored at -70 degrees C within 2 h after phlebotomy. Compared to viral loads in frozen EDTA plasma, those in PPT tube plasma that was frozen immediately and either separated or shipped in situ were not significantly different. Viral loads in PPT tube plasma after storage for 6 h at either room temperature or 4 degrees C, followed by shipment at ambient temperature or on wet or dry ice, were not significantly different from baseline viral loads in EDTA or PPT plasma. The results of this study indicate that the HIV load in PPT tube plasma is equivalent to that in standard EDTA plasma. Plasma viral load is not affected by storage or shipment temperature when plasma is collected in PPT tubes. Furthermore, plasmas can be shipped in spun PPT tubes, and the tubes provide a safer and more convenient method for sample collection and transport than regular EDTA tubes.

Effects of exercise training on older patients with major depression

BACKGROUND

Previous observational and interventional studies have suggested that regular physical exercise may be associated with reduced symptoms of depression. However, the extent to which exercise training may reduce depressive symptoms in older patients with major depressive disorder (MDD) has not been systematically evaluated.

OBJECTIVE

To assess the effectiveness of an aerobic exercise program compared with standard medication (ie, antidepressants) for treatment of MDD in older patients, we conducted a 16-week randomized controlled trial.

METHODS

One hundred fifty-six men and women with MDD (age, > or = 50 years) were assigned randomly to a program of aerobic exercise, antidepressants (sertraline hydrochloride), or combined exercise and medication. Subjects underwent comprehensive evaluations of depression, including the presence and severity of MDD using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and Hamilton Rating Scale for Depression (HAM-D) and Beck Depression Inventory (BDI) scores before and after treatment. Secondary outcome measures included aerobic capacity, life satisfaction, self-esteem, anxiety, and dysfunctional cognitions.

RESULTS

After 16 weeks of treatment, the groups did not differ statistically on HAM-D or BDI scores (P = .67); adjustment for baseline levels of depression yielded an essentially identical result. Growth curve models revealed that all groups exhibited statistically and clinically significant reductions on HAM-D and BDI scores. However, patients receiving medication alone exhibited the fastest initial response; among patients receiving combination therapy, those with less severe depressive symptoms initially showed a more rapid response than those with initially more severe depressive symptoms.

CONCLUSIONS

An exercise training program may be considered an alternative to antidepressants for treatment of depression in older persons. Although antidepressants may facilitate a more rapid initial therapeutic response than exercise, after 16 weeks of treatment exercise was equally effective in reducing depression among patients with MDD.

Assay of plasma samples representing different HIV-1 genetic subtypes: an evaluation of new versions of the amplicor HIV-1 monitor assay

Quantification of plasma HIV-1 RNA levels has rapidly become the main tool for monitoring disease progression and treatment. However, some first-generation assays do not accurately quantify all HIV-1 subtypes. This study compares the first-generation and two newer prototype Amplicor HIV-1 Monitor assays (Roche Diagnostic Systems) in terms of their performance in quantifying HIV-1 RNA in stored plasma samples from 101 individuals infected with various genetic subtypes of HIV-1 (28 subtype A, 18 B, 26 C, 20 D, 2 E, 3 G, 2 H, and 2 J). The HIV-1 subtype had previously been determined by direct sequencing of the V3 domain of the env gene. The results from the three assays agreed for subtypes B and C, as well as for most subtype D samples. In contrast, the first-generation assay reported significantly lower plasma HIV-1 RNA levels than did the two newer versions of the assay for most subtype A, E, G, and H samples. There were no differences in mean plasma HIV-1 RNA levels between individuals infected with subtypes A, B, C, and D if the results from the two newer test versions were used, and if an adjustment was made between subtypes for differences in CD4 count. Thus, this study confirms that the first-generation assay does not accurately quantify HIV-1 RNA levels in many individuals infected with subtype A, E, G, and H. These problems appeared to have been greatly reduced in the two new prototype versions.

Chalcone reductase-homologous transcripts accumulate during development of stem-borne nodules on the tropical legume Sesbania rostrata

During a search for genes with induced or enhanced expression in the early stages of development of stem-borne nodules on Sesbania rostrata, a cDNA with homology to chalcone reductase (CHR) genes was isolated. Here, we describe the characterization of a full-length CHR cDNA (Srchr1) and the pattern of CHR transcript accumulation in stem-borne nodules. Expression was correlated with both nodule development and bacterial invasion. In young nodules, CHR transcripts were observed in cells of the parenchyma, in cells around the nodule vascular bundles, and in the uninfected cells of the central tissue.

Analysis of postdischarge change in a dual diagnosis population

Many individuals with serious mental illnesses have co-occurring drug and alcohol problems. The research reported in this article examined an integrated inpatient mental illness-chemical dependency program and compared it with standard inpatient psychiatric treatment for two groups: those demonstrating high change from baseline to two-months postdischarge and those with negative or no change. Univariate analyses revealed significant differences in the change groups on baseline personal-clinical characteristics and on aspects of their social and physical environments. The results have implications for improving mental health practice by better predicting patients who will optimally benefit from inpatient treatment.

Petawatt laser pulses

We have developed a hybrid Ti:sapphire-Nd:glass laser system that produces more than 1500 TW (1.5 PW) of peak power. The system produces 660 J of power in a compressed 440+/-20 fs pulse by use of 94-cm master diffraction gratings. Focusing to an irradiance of >7x10(20) W/cm (2) is achieved by use of a Cassegrainian focusing system employing a plasma mirror.

Efficiencies of four versions of the AMPLICOR HIV-1 MONITOR test for quantification of different subtypes of human immunodeficiency virus type 1

Three versions of a commercial human immunodeficiency virus (HIV) type 1 (HIV-1) load test (the AMPLICOR HIV-1 MONITOR Test versions 1. 0, 1.0+, and 1.5; Roche Diagnostics, Branchburg, N.J.) were evaluated for their ability to detect and quantify HIV-1 RNA of different genetic subtypes. Plasma samples from 96 patients infected with various subtypes of HIV-1 (55 patients infected with subtype A, 9 with subtype B, 21 with subtype C, 2 with subtype D, 7 with subtype E, and 2 with subtype G) and cultured virus from 29 HIV-1 reference strains (3 of subtype A, 6 of subtype B, 5 of subtype C, 3 of subtype D, 8 of subtype E, 3 of subtype F, and 1 of subtype G) were tested. Detection of subtypes A and E was significantly improved with versions 1.0+ and 1.5 compared to that with version 1. 0, whereas detection of subtypes B, C, D, and G was equivalent with the three versions. Versions 1.0, 1.0+, and 1.5 detected 65, 98, and 100% of the subtype A-infected samples from patients, respectively, and 71, 100, and 100% of the subtype E-infected samples from patients, respectively. Version 1.5 yielded a significant increase in viral load for samples infected with subtypes A and E (greater than 1 log10 HIV RNA copies/ml). For samples infected with subtype B, C, and D and tested with version 1.5, only a slight increase in viral load was observed (<0.5 log10). We also evaluated a prototype automated version of the test that uses the same PCR primers as version 1.5. The results with the prototype automated test were highly correlated with those of the version 1.5 test for all subtypes, but were lower overall. The AMPLICOR HIV-1 MONITOR Test, version 1.5, yielded accurate measurement of the HIV load for all HIV-1 subtypes tested, which should allow the test to be used to assess disease prognosis and response to antiretroviral treatment in patients infected with a group M HIV-1 subtype.

Use of PCR in detection of Mycobacterium avium complex (MAC) bacteremia: sensitivity of the assay and effect of treatment for MAC infection on concentrations of human immunodeficiency virus in plasma

We evaluated the sensitivity and specificity of a PCR-based qualitative test for the rapid diagnosis of Mycobacterium avium-M. intracellulare complex (MAC) bacteremia in patients with AIDS disease. Eleven subjects with newly culture-proven MAC bacteremia had the following tests performed at biweekly intervals during the first 8 weeks of therapy: blood culture, Mycobacterium-specific PCR, and quantitative human immunodeficiency virus (HIV) viral-load testing. Mycobacterium genus-specific biotinylated primers were used to amplify a sequence of approximately 582 nucleotides within the 16S rRNA genes of M. avium and M. intracellulare. Detection of the amplified product was performed with an oligonucleotide probe-coated microwell plate combined with an avidin-horseradish peroxidase-tetramethylbenzidine conjugate-substrate system. While not as sensitive as BACTEC culture, PCR detected 17 of 18 specimens which grew >/=40 organisms/ml (94.4% sensitivity) and 9 of 16 specimens which grew </=40 organisms/ml (56.3% sensitivity). No clear change in HIV viremia occurred in response to successful treatment of patients' MAC bacteremia. Use of the PCR test allowed detection of MAC bacteremia in 1 day, with a sensitivity similar to those of quantitative blood culture techniques, and it may prove useful for rapid screening of suspected cases. HIV viremia was unaffected by 8 weeks of MAC therapy.

Ultrasensitive reverse transcription-PCR assay for quantitation of human immunodeficiency virus type 1 RNA in plasma

With the recent introduction of combination therapy, human immunodeficiency virus type 1 (HIV-1) RNA levels in plasma have been dramatically reduced, frequently to below the limit of quantitation (400 copies/ml of plasma) of the AMPLICOR HIV-1 MONITOR Test (Roche Diagnostic Systems). To achieve enhanced sensitivity of the AMPLICOR HIV-1 MONITOR Test, a modified specimen preparation procedure that allows input of RNA from 10-fold more plasma per amplification reaction was developed. This "ultrasensitive" method allows the accurate quantitation of plasma HIV-1 RNA levels as low as 50 copies/ml. A precision study yielded average within-run and between-run coefficients of variation (CV) of 24.8 and 9.6%, respectively. A multicenter reproducibility study demonstrated that the laboratory-to-laboratory reproducibility of this assay is good, with an average CV of 32%. The linear range of this test is between 50 and 50,000 copies/ml of plasma. RNA concentrations measured by the ultrasensitive and standard HIV-1 MONITOR tests exhibited good agreement within the shared linear range of the two methods. The two measurements were within a factor of 2 for 91% of the specimens tested, with the concentration measured by the ultrasensitive method being only slightly lower (median, 22% lower). Preliminary studies suggest that this assay will prove to be useful for predicting the stability of viral suppression in patients whose RNA levels drop below 400 copies/ml in response to highly active antiretroviral therapy.

A study of the workforce in emergency medicine

STUDY OBJECTIVE

Emergency medicine has progressed significantly since its initial recognition as a medical specialty. Relatively little factual information is known, however, regarding who or how many physicians practice emergency medicine. The purpose of this study is to determine the total number of physicians practicing clinical emergency medicine during a specified period, to describe certain characteristics of those individuals, and to estimate the total number of full-time equivalents (FTEs), as well as the total number of individuals needed to staff those FTEs.

METHODS

Data were gathered from a survey of a random sample of 2,062 hospitals drawn from a population of 5,220 hospitals reported by the American Hospital Association as having, or potentially having, an emergency department. The survey instrument addressed items such as descriptive data on the institution, enumeration of physicians in the ED, as well as the total number working during the period June 1, 1997, through June 14, 1997. Demographic data on the individuals were also collected.

RESULTS

A total of 942 hospitals responded (a 45.7% return rate). These hospitals reported a total of 5,872 physicians were working during the specified period, or an average of 7.48 persons scheduled per institution. The physicians were scheduled for a total of 297,062 hours. The average standard for FTE was 40 clinical hours per week. This equates to 3,713 FTEs or 4.96 FTEs per institution. The ratio of persons to FTEs was 1.51:1. With regard to demographics, 83% of the physicians were men and 81% were white. Their average age was 42 years. As to professional credentials, 58% were emergency medicine-residency trained and 53% were board certified in emergency medicine; 46% were certified by the American Board of Emergency Medicine.

CONCLUSION

Given that there are 4,945 hospitals with EDs and given that the data indicate there are 4.96 FTEs per ED, the total number of FTEs is projected to be 24,548 (standard error = 437). Given further that the data indicate a physician/FTE ratio of 1.51:1, we conclude that there are 36,990 persons (standard error = 683) needed to staff those FTEs. When adjusted for persons working at more than one ED, that number is reduced to 32,026.