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This Week in JAMA
JAMA. 2005;293:771.
Medical Applications of Biotechnology
A JAMA Theme Issue
Edited by Phil B. Fontanarosa, MD, and Catherine D. DeAngelis, MD, MPH
Detecting Germline Mutations in Colorectal Cancer
Identification of specific DNA mismatch repair gene mutations in colorectal cancers may improve clinical management, but current DNA sequencing techniques do not detect all mutations. Casey and colleagues report results of a study comparing conversion analysis vs DNA sequencing to detect 3 mismatch repair mutations in colorectal cancers. The authors found that conversion analysis detected more deleterious mutations than conventional DNA sequencing.
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Bladder Cancer Detection With a Proteomic Assay
Urine cytology is one test used in the diagnosis of bladder cancer, but it has low sensitivity. Grossman and colleagues investigated whether a proteomic assay for a tumor marker, nuclear matrix protein NMP22, in voided urine and available at point-of-care, could improve detection of malignancy in patients with risk factors or symptoms of bladder cancer. The authors found that the NMP22 assay to have positive results in 44 of 79 patients with confirmed bladder cancer, including 4 tumors not seen on cystoscopy, whereas urine cytology had positive results in only 12 of 76 patients.
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Intermittent Viremia in Patients Receiving HAART
Patients infected with human immunodeficiency virus type 1 (HIV-1) who achieve virus suppression while receiving highly active antiretroviral therapy (HAART) are known to experience intermittent episodes of detectable viremia ("blips"). Nettles and colleagues tested the hypothesis that these blips are random and clinically insignificant by assessing HIV-1 RNA levels every 2 to 3 days over 3 to 4 months in 10 patients. They found blips in 9 of 10 patients, results that were statistically consistent with random assay variation and were not associated with concurrent clinical factors, antiretroviral drug concentrations, or drug resistance mutations.
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Single-Donor, Low-Dose Islet Transplantation
Recent trials of multidonor islet transplantation for type 1 diabetes have demonstrated success, but single-donor transplants would be preferable by allowing more patients access to this treatment and reducing risk. Hering and colleagues investigated single-donor islet transplant with initiation of immunosuppression prior to transplantation in all 8 study patients. There were no serious transplant- or immunosuppression-related adverse events, and 5 of the patients remained insulin-independent at 1 year of follow-up.
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Fetal mRNA in Amniotic Fluid
Monitoring fetal development is currently limited to noninvasive methods. Larrabee and colleagues hypothesized that if fetal messenger RNA (mRNA) could be detected in amniotic fluid, it could be analyzed to study fetal gene expression, which could reflect fetal well-being. They describe the extraction of fetal mRNA from cell-free amniotic fluid samples, amplification of the mRNA, and analysis using gene expression microarrays. Among their findings were gene expression changes related to sex, gestational age, and disease status.
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Identifying Fetal Point Mutations in Maternal Plasma
Monogenic disorders such as  -thalassemia frequently involve single nucleotide exchange or point mutations, which are challenging to detect using current techniques. In previous work, Li and colleagues determined that circulatory fetal DNA can be reliably separated from maternal DNA in samples of maternal plasma using a size-fractionation technique. In this issue of JAMA, they report successful application of the size-fractionation technique to detect paternally inherited -thalassemia point mutations.
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Medical News & Perspectives
Researchers are tackling big projects aimed at improving human health, including an effort to develop cancer biomarkers and a venture to use microbial "factories" to supply a key antimalaria drug to developing countries.
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Intellectual Property
Conflicts in defining ownership and control of intellectual contributions to biomedical discoveries.
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CLINICIAN’S CORNER
Molecular Imaging
Contempo Updates
Advances in molecular imaging techniques and agents.
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Technology in the OR
The use and future of robotic surgery.
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JAMA Patient Page
For your patients: Information about bladder cancer.
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