4D-Dynamic Contrast-Enhanced MRI for Preoperative Localization in Patients with Primary Hyperparathyroidism.

BACKGROUND AND PURPOSE: Our aim was to test the hypothesis that our recently introduced 4D-dynamic contrast-enhanced MR imaging with high spatial and temporal resolution has equivalent accuracy to 4D-CT for preoperative gland localization in primary hyperparathyroidism without requiring exposure to ionizing radiation. MATERIALS AND METHODS: Inclusion criteria were the following: 1) confirmed biochemical diagnosis of primary hyperparathyroidism, 2) preoperative 4D-dynamic contrast-enhanced MR imaging, and 3) surgical cure with >50% decrease in serum parathyroid hormone intraoperatively. 4D-dynamic contrast-enhanced studies were reviewed independently by 2 neuroradiologists to identify the side, quadrant, and number of abnormal glands, and compared with surgical and pathologic results. RESULTS: Fifty-four patients met the inclusion criteria: 37 had single-gland disease, and 17, multigland disease (9 with double-gland hyperplasia; 3 with 3-gland hyperplasia; and 5 with 4-gland hyperplasia). Interobserver agreement (κ) for the side (right versus left) was 0.92 for single-gland disease and 0.70 for multigland disease. Interobserver agreement for the quadrant (superior versus inferior) was 0.70 for single-gland disease and 0.69 for multigland disease. For single-gland disease, the gland was correctly located in 34/37 (92%) patients, with correct identification of the side in 37/37 (100%) and the quadrant in 34/37 (92%) patients. For multigland disease, the glands were correctly located in 35/47 (74%) patients, with correct identification of the side in 35/47 (74%) and the quadrant in 36/47 (77%). CONCLUSIONS: The proposed high spatial and temporal resolution 4D-dynamic contrast-enhanced MR imaging provides excellent diagnostic performance for preoperative localization in primary hyperparathyroidism, with correct gland localization of 92% for single-gland disease and 74% in multigland disease, superior to 4D-CT studies.

BEARscc determines robustness of single-cell clusters using simulated technical replicates.

Single-cell messenger RNA sequencing (scRNA-seq) has emerged as a powerful tool to study cellular heterogeneity within complex tissues. Subpopulations of cells with common gene expression profiles can be identified by applying unsupervised clustering algorithms. However, technical variance is a major confounding factor in scRNA-seq, not least because it is not possible to replicate measurements on the same cell. Here, we present BEARscc, a tool that uses RNA spike-in controls to simulate experiment-specific technical replicates. BEARscc works with a wide range of existing clustering algorithms to assess the robustness of clusters to technical variation. We demonstrate that the tool improves the unsupervised classification of cells and facilitates the biological interpretation of single-cell RNA-seq experiments.

Ethical issues in non-intervention trials for thyroid cancer.

In recent years, the increasing numbers of small, apparently indolent thyroid cancers diagnosed in the world have encouraged investigators to consider non-intervention as an alternative to surgical management. In the following pages, the prospect of a non-intervention trial for thyroid cancer is considered with attention to the ethical issues that such a trial might raise. Such a non-intervention trial is analyzed relative to 7 ethical considerations: the social or scientific value of the research, the scientific validity of the trial, the necessity of fair selection of participants, a favorable risk-benefit ratio for trial participants, independent review of the trial, informed consent, and allowing the study participants to withdraw from the trial. A non-intervention trial for thyroid cancer is also considered relative to the central concept of equipoise.

The education potential of the pharmacogenetics and pharmacogenomics knowledge base (PharmGKB).

The pharmacogenetics and pharmacogenomics knowledge base (PharmGKB, http://www.pharmgkb.org) is a publicly available internet resource dedicated to the integration, annotation, and aggregation of pharmacogenomic knowledge. PharmGKB is a repository for pharmacogenetic and pharmacogenomic data, and curators provide integrated knowledge in terms of gene summaries, pathways, and annotated literature. Although PharmGKB is primarily directed toward catalyzing new research, it also has utility as a source of information for education about pharmacogenomics.

An unusual presentation of metastatic colon cancer to the lung.

A 75-year-old man with a history of resected colon carcinoma presented to his primary care physician because of a new onset of coughing. The patient had expectorated a small piece of solid tissue; pathologic examination of the tissue found it to be consistent with metastatic colon adenocarcinoma. After further work-up, a right upper lobectomy was performed. The surgical specimen removed during the lobectomy showed a tumor that was histologically identical to the patient's prior colonic primary tumor.

Modelling instream nitrogen variability in the Dee catchment, NE Scotland.

The Integrated Nitrogen in CAtchments model (INCA) was applied to the River Dee, Aberdeenshire, NE Scotland. To a first approximation the model was able to simulate the annual mean streamwater NO3-N concentrations observed along the length of the main channel. This provided the basis for using INCA to subsequently explore the effects of N deposition and land use management on streamwater NO3-N concentrations and loads. On an annual timescale, the model predictions suggest that NO3-N concentrations will decrease by 5% following a 20% reduction in fertiliser application. Furthermore, model results also suggest that a 50% increase in N deposition will cause a 15% increase in the streamwater NO3-N concentrations. The utility of INCA as a tool for catchment management is discussed, current limitations are highlighted and possible improvements are suggested.

Office of clinical pharmacology science day: a forum to stimulate innovation in clinical pharmacology.

The Office of Clinical Pharmacology (OCP) of the US Food and Drug Administration (FDA) has hosted an office-wide event called Science Day (SD) since 1999. SD 2012 included presentations on physiologically based pharmacokinetic models, exposure-response analyses, and other research projects. SD provides a forum for showcasing clinical pharmacology (CP) research within the OCP and provides an opportunity for professional development. This article discusses the evolution of Science Day and then focuses on SD 2012 as an example platform for promotion of regulatory research.

Effect of genetic variation in the organic cation transporter 1, OCT1, on metformin pharmacokinetics.

The goal of this study was to determine the effects of genetic variation in the organic cation transporter 1, OCT1, on the pharmacokinetics of the antidiabetic drug, metformin. Twenty healthy volunteers with known OCT1 genotype agreed to participate in the study. Each subject received two oral doses of metformin followed by collection of blood and urine samples. OCT1 genotypes had a significant (P<0.05) effect on metformin pharmacokinetics, with a higher area under the plasma concentration-time curve (AUC), higher maximal plasma concentration (Cmax), and lower oral volume of distribution (V/F) in the individuals carrying a reduced function OCT1 allele (R61C, G401S, 420del, or G465R). The effect of OCT1 on metformin pharmacokinetics in mice was less than in humans possibly reflecting species differences in hepatic expression level of the transporter. Our studies suggest that OCT1 genotype is a determinant of metformin pharmacokinetics.

Surgical management of the neck in thyroid cancer.

Thyroid cancer is a relatively common clinical problem. The American Cancer Society has estimated 1,050,000 newly diagnosed cancers in 1999 in the United States, of which 16,000 are expected to be of thyroid origin. Although most thyroid cancers have an excellent prognosis as compared with other malignant tumors, it is estimated that approximately 1,225 deaths will be attributed to the disease [1].