OBJECTIVETo determine the rate of adherence to postpartum glycemic testing in women with gestational diabetes mellitus (GDM) and the performance of fasting plasma glucose (FPG) versus the 75-g oral glucose tolerance test (OGTT) in detecting postpartum glucose intolerance.RESEARCH DESIGN AND METHODSThe study was a retrospective cohort of 1,006 women with GDM attending a pregnancy diabetes clinic.RESULTSPostpartum screening was completed in 438 (48%) women. Women nonadherent to testing had higher parity (1.10 vs. 0.87) and were less likely to require insulin for management of their GDM. Among women who were tested, 89 (21%) had an abnormal result, only 25 (28%) of whom were identified by FPG. Factors associated with abnormal postpartum diabetes screening include non-Caucasian ethnicity, previous GDM, higher A1C, and OGTT values during pregnancy and treatment with insulin.CONCLUSIONSThe rate of postpartum diabetes screening is low, and FPG lacks sensitivity as a screening test in comparison with OGTT.
Polymerase chain reaction (PCR)-based analysis for detecting immunoglobulin heavy chain gene (IgH)rearrangements in lymphoproliferative disorders is well established. The presence of one or two discrete bands is interpreted as a monoclonal proliferation, whereas a smear pattern represents a polyclonal population. Prompted by our observation of discrete bands in histologically reactive processes with a relative paucity of B cells, we sought to determine whether low numbers of B cells in biopsy specimens could artifactually produce pseudomonoclonal bands. We performed IgH PCR analysis on serially diluted DNA samples from 5 B cell non-Hodgkin's lymphomas (B-NHLs), 5 reactive lymph nodes, 5 reactive tonsils and 10 microdissected germinal centers from a lymph node with follicular hyperplasia. We also assessed multiple aliquots of DNA samples from small biopsy specimens of reactive lymphocytic processes from the stomach (5 cases). PCR products were evaluated using high resolution agarose or polyacrylamide gels, and DNA sequencing was performed on IgH PCR products from two reactive germinal centers, which yielded monoclonal bands of identical size. The utility of molecular techniques such as Southern blot hybridization (SBH) analysis and polymerase chain reaction (PCR) in the assessment of clonality in lymphoproliferative disorders is well established. Although SBH is a fairly sensitive and specific method, its utility as a routine diagnostic tool is hampered by its requirement for high quality DNA, its labor-intensive nature, and its consequent long turnaround time. On the other hand, the rapid and less labor-intensive PCR continues to gain popularity as a technique for the assessment of clonality in lymphoproliferative disorders. 1,2 The results obtained with antigen receptor gene PCR correlate well with the results of SBH. [3][4][5] PCR-based assays have additional advantages over SBH analysis. PCR requires smaller quantities of DNA, and high molecular weight DNA is not necessary. Therefore, PCR has been applied to small biopsies and fixed paraffin-embedded tissues, which are generally unsuitable for SBH analysis. 6 PCR is extremely sensitive and can detect 1 positive cell in a background of 10 5 negative cells. Immunoglobulin heavy chain (IgH) PCR is capable of detecting 1 monoclonal B cell in a background of 10 2 to 10 3 polyclonal B cells. 7 The extreme sensitivity of PCR also constitutes a potential source for pitfalls in the interpretation of PCR-based antigen receptor gene rearrangement studies. Clearly, contamination is a frequent concern. Additionally, we have observed discrete bands in samples obtained from small biopsy specimens in which histological and immunophenotypic evaluation revealed a reactive process. We believe that the discrete bands generated in this situation are related to the paucity of B
We describe a case of concomitant Graves' disease and demyelination, with optic neuritis and cerebellar dysfunction, in an adolescent girl. Autoimmune thyroid disease with encephalopathy is the hallmark of Hashimoto's encephalopathy, linking thyroid and central nervous system dysfunction. However, to our knowledge, Graves' disease has not been previously reported in association with clinically isolated demyelinating disease in childhood.
We read with interest the article by Elenitoba-Johnson et al, 1 in which the authors demonstrated potential false positive results obtained using a polymerase chain reaction (PCR)-based method to determine B cell clonality. This is an important observation, and one must be cognizant of the potential for detecting clones of uncertain clinical significance in specimens with very few B cells.However, we would like to make the observation that the source of this problem is the hemi-nested PCR method used by the authors, which is compounded when only small amounts of DNA are used in the assay. When a standard single-step PCR method is used in specimens with very few B cells, one would see essentially no PCR product, leading one to conclude that either there are too few B cells to detect with the PCR method, or the DNA is of insufficient quality or quantity for PCR analysis. The latter case can be ruled out using the proper controls.In our laboratory, we are frequently asked to detect B cell clones in the peripheral blood or bone marrow of patients who have been treated with anti-B cell antibodies for B cell lymphoma. These patients routinely have virtually no B cells detectable by flow cytometry, and essentially no PCR product is seen with a single-step method using VH Framework 3/JH primers and capillary electrophoresis to detect fluorescently labeled PCR products. Occasionally we see several very faint PCR products, but the intensity if the products is not sufficient for us to make a diagnosis of clonality. The adequacy of the DNA is confirmed using primers for a control gene. In this situation, we inform the ordering physician that no PCR products were obtained, consistent with an absence of B cells in the specimen.Admittedly, it is unsatisfying to report such inconclusive results. However, we feel that by using a single-step PCR method, we can provide useful diagnostic information when enough B cells are present to make a diagnosis. In the absence of B cells, we do not have to contend with possible false positive results and the potential clinical consequences thereof. Authors' Reply:We appreciate the interest of Drs. Sabath, Wood, and Kussick in our recent article. 1 Our study highlighted the potential for incorrectly assigning monoclonal status to samples containing polyclonal or oligoclonal B cell populations. In our study, we compared hemi-nested and non-nested single-step PCR approaches followed by polyacrylamide gel electrophoresis. While we state that "the hemi-nested assay is more prone to the generation of pseudo-monoclonal bands" in agreement with their experience, we also demonstrate that this phenomenon may occur, albeit less frequently, in non-nested assays. 1 Recognition of this phenomenon is particularly important when the DNA source is fixed paraffin-embedded tissue, where the DNA quality may be suboptimal. This technically diminishes the DNA target that is available for amplification.Whereas an amplification control such as a housekeeping gene would be expected to yield a distinct PCR product ge...
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