Biomedical subjects

Julie E Niemela

Publications and source records attributed to Julie E Niemela.

7 recordsLinked to original sources

PubMed2005

Single nucleotide polymorphisms in the apoptosis receptor gene TNFRSF6.

The homotrimeric Fas receptor, an inducer of lymphocyte apoptosis, plays a critical role in cellular pathways of immune homeostasis and immunologic tolerance. Inherited and acquired defects in the Fas gene, TNFRSF6 (tumor necrosis factor receptor superfamily member 6) have been associated with human autoimmune lymphoproliferative syndrome (ALPS) and a spectrum of other complex autoimmune diseases and malignancies. In addition to over 60 deleterious mutations associated with dominant inhibitory defects or null mutations of TNFRSF6, several sequence variants have been noted. To facilitate interpretation of genotypes of this important locus, we sequenced DNA from unrelated, healthy Caucasians and African Americans. Two new and 12 previously recorded SNPs were confirmed, and their allele frequencies were determined. We also investigated haplotype frequencies and linkage disequilibrium (LD) coefficients for these SNPs in Caucasians. Four TNFRSF6 SNP pairs were found to be in strong LD. The TNRFSF6 SNPs are useful for linkage and loss of heterozygosity studies probing the role of Fas-mediated apoptosis in autoimmune diseases and malignancies.

Black or African American↗

PubMed2005

Magnesium (mg) retention and mood effects after intravenous mg infusion in premenstrual dysphoric disorder.

BACKGROUND: Conflicting data exist regarding the presence of magnesium (Mg) deficiency and the therapeutic efficacy of Mg in premenstrual syndrome or premenstrual dysphoric disorder (PMDD). METHODS: The % Mg retention was determined using 24-hour urinary Mg excretion and the total dose of Mg given intravenously. In women with (n = 17) and without (n = 14) prospectively diagnosed PMDD, several blood measures of Mg and mood were obtained before, immediately after, and the day following an intravenous Mg (.1 mmol/kg) loading dose. A positive mood response was seen under open conditions; as open Mg infusion improved mood, subsequent PMDD patients (n = 10) were randomized in a double-blind, placebo-controlled, crossover fashion. RESULTS: Patients (31.5%) and control subjects (27.5%) retained comparable mean percentages of Mg. Neither group differed in measures of mean Mg before, immediately after, or the day following Mg infusion. Although there was a time effect for all mood measures in the patient group (p < .01 for all), there was neither a treatment nor time-by-treatment effect. CONCLUSIONS: Contrary to prior reports, we found no evidence of Mg deficiency in women with PMDD compared with control subjects. Furthermore, Mg was not superior to placebo in the mitigation of mood symptoms in women with PMDD.

Adult↗

PubMed2005

Histologic features of sinus histiocytosis with massive lymphadenopathy in patients with autoimmune lymphoproliferative syndrome.

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder associated with defects in Fas-mediated apoptosis, characterized most often by childhood onset of lymphadenopathy, splenomegaly, hypergammaglobulinemia, and autoimmune phenomena. Children with sinus histiocytosis with massive lymphadenopathy (SHML) have a somewhat similar clinical phenotype in which prominent adenopathy also is associated with hypergammaglobulinemia, and autoimmune phenomena are reported in 10-15% of cases. We observed histopathological features of SHML in the lymph nodes of some of our ALPS patients, further suggesting an association between these two disorders. We, thus, reviewed the lymph nodes from 44 patients ALPS type Ia, all of whom were confirmed to have germline mutations in the TNFRSF6 gene encoding Fas (CD95/Apo-1). Eighteen of 44 (41%) patients had a histiocytic proliferation resembling SHML. The affected patients included 15 males and 3 females ranging in age from 11 months to 30 years at the time of the LN biopsy. The lymph nodes contained S-100+ histiocytes with characteristic nuclear features of SHML, and showed evidence of emperipolesis in both hematoxylin and eosin (H and E) and immunostained sections. The extent of the histiocytic proliferation was variable, being confluent in 2 cases, multifocal in 13, and only evident as isolated SHML-type histiocytes in 3. In lymph nodes without confluent SHML changes, increased numbers of CD3+CD4-CD8+ (double negative) alphabeta T-cells, also negative for CD45RO, a feature of ALPS, could be identified in the paracortex. Furthermore, because SHML shares many clinical features with ALPS, we sought evidence of ALPS in sporadic SHML. We attempted to sequence TNFRSF6 DNA from archived tissue of 14 cases of Rosai-Dorfman disease. Full sequencing of the gene was successful in 4 of the cases; no mutations were identified. Nevertheless, our observations suggest that histologic features of SHML are part of the pathologic spectrum of ALPS type Ia. It remains to be determined if some cases of apparently sporadic SHML may be associated with heritable defects in Fas-mediated apoptosis.

Adolescent↗

PubMed2004

Human nuclear factor kappa B essential modulator mutation can result in immunodeficiency without ectodermal dysplasia.

BACKGROUND: Many receptors rely on the appropriate activation of nuclear factor (NF) kappa B to induce cellular function. This process depends critically on the phosphorylation of the inhibitor of NF-kappa B (I kappa B) by the I kappa B kinase. This targets I kappa B for ubiquitination and degradation, allowing NF-kappa B to translocate to the nucleus, where it can direct transcription. Hypomorphic human mutations affecting one I kappa B kinase component, the NF-kappa B essential modulator (NEMO), result in impaired signaling from receptors required for ectodermal development and immune function. Male subjects with these mutant NEMO molecules have an X-linked syndrome known as ectodermal dysplasia with immunodeficiency, which is characterized by severe infections, with herpesviruses, bacteria, and mycobacterial susceptibility. OBJECTIVE: We sought to genetically and biochemically characterize a patient with a mutant NEMO molecule without ectodermal abnormalities. METHODS: We evaluated NEMO in a patient who had immunodeficiency and atypical mycobacterial infection but normal ectoderm. RESULTS: We identified a novel NEMO mutant causing immunodeficiency without ectodermal dysplasia. The mutation, which altered the exon 9 splice site, was present in cells of ectodermal and hematopoetic origin and resulted in a heterogeneous mixture of mutant and wild-type cDNA species. Immunologic function was variably impaired, with reduced CD40-induced B-cell proliferation, partially reduced NF-kappa B p65 nuclear translocation, and variable Toll-like receptor-induced TNF production. This variability might be explained by an inconsistent ratio of mutant to wild-type NEMO. The lack of any ectodermal phenotype, however, suggested a separation in the hematopoetic and ectodermal function of NEMO that leads to NF-kappa B activation. CONCLUSION: Mutation of the gene encoding NEMO can result in immunodeficiency without ectodermal dysplasia.

Adolescent↗

PubMed2003

Diagnostic paradigm for evaluation of male patients with chronic granulomatous disease, based on the dihydrorhodamine 123 assay.

BACKGROUND: Chronic granulomatous disease (CGD) is a phagocyte disorder caused by mutations in nicotinamide dinucleotide phosphate (NADPH) oxidase subunits. The dihydrorhodamine 123 (DHR) assay is an effective test for CGD that for most patients also might help to differentiate between the 2 most common forms, X-linked (X) gp91(phox) defect CGD and autosomal recessive (AR) p47(phox) defect CGD. However, some male patients with X-CGD have DHR patterns that overlap the AR-CGD pattern. OBJECTIVE: The purpose of this investigation was to develop a diagnostic paradigm to delineate male patients with X-CGD expressing a DHR pattern suggestive of p47(phox) deficiency. METHODS: The DHR assay measured change in fluorescence of DHR-loaded granulocytes after phorbol myristate acetate (PMA) stimulation. Western blot analysis measured the presence of NADPH oxidase subunits gp91(phox), p47(phox), p67(phox), and p22(phox). CYBB exonic sequencing was performed on PCR-amplified genomic DNA through use of intronic flanking primers. Ferricytochrome-c assay evaluated specific superoxide production by PMA-stimulated granulocytes. RESULTS: Although 83% of patients with X-CGD have virtually no neutrophil DHR activity, we found that 17% of patients, proven to have X-CGD by other criteria, have modest DHR activity that is most consistent with p47(phox) deficiency. We describe a diagnostic paradigm to deal with such patients, and we present 2 cases, along with results of additional studies, including carrier evaluation, protein assessment, and mutation analysis, that are useful in establishing the genotype under these circumstances. DHR assays from the 2 patients described showed a fluorescence shift most characteristic of p47(phox)-AR-CGD; however, each of the patients' mothers showed mosaicism with a bimodal DHR pattern. Patient 1 had some gp91(phox) protein with a Y41D mutation and modest superoxide activity. Patient 2 had a normal level of gp91(phox) protein with a C537R mutation without detectable superoxide activity, as determined by ferricytochrome-c assay, despite the modest DHR activity. CONCLUSIONS: Evaluation of male patients with CGD with modest DHR activity should initially include evaluation of potential female carriers for mosaicism with the use of the DHR assay. In circumstances in which this is uninformative, patients should be referred to centers capable of additional testing, including Western blot analysis and CYBB mutation analysis, to clarify the disease genotype.

Adult↗

PubMed2002

CYBB mutation analysis in X-linked chronic granulomatous disease.

Chronic granulomatous disease (CGD) results from mutations of phagocyte NADPH oxidase. Seventy percent are X-linked (X-)CGD with absent or defective gp91(phox) protein encoded by the CYBB gene. A subset of X-CGD patients demonstrates partial oxidase activity and/or varied levels of the gp91(phox) protein. Definitive genotypic diagnosis in these unusual patients requires mutation analysis. Typically, CYBB mutation analysis has relied on initial screening of cDNA by single-stranded conformation polymorphism analysis, followed by selective sequencing. We report a fluorescent, automated method for CYBB mutation analysis using genomic DNA that provides more rapid and reliable results. Moreover, the use of genomic DNA in this approach allows mutation detection in the mRNA coding region, promoter/enhancer region, and intronic sequences flanking splice junctions and does not require mRNA preparation. The PCR conditions were optimized for each exon, including those with A+T-rich regions. We analyzed DNA from two unusual X-CGD patients and established the genetic basis for their phenotype. We also sequenced 100 normal X chromosomes to establish wild-type consensus sequences and identify polymorphisms.

Base Sequence↗

PubMed2002

Effects of interleukin 2 therapy on lymphocyte magnesium levels.

Interleukin 2 (IL-2) can cause partial or complete tumor regression in approximately 20% of patients with renal cell carcinoma. Among the many physiologic effects of IL-2, decreased serum levels of the divalent cations magnesium (Mg) and calcium have been demonstrated, with corresponding decreases in their urinary excretion. We investigated the effect of IL-2 on lymphocyte Mg levels among patients receiving three different dosing regimens. Twenty-eight patients with metastatic renal cell carcinoma were treated with high-dose intravenous, low-dose intravenous, or subcutaneous IL-2 therapy. Serum ionized Mg, urinary Mg, and peripheral blood mononuclear cell Mg levels were measured in samples from patients during treatment and compared with pretreatment levels. Serum Mg and ionized Mg levels decreased for all patients within 12 hours of treatment (P <.005) and remained low for the duration of therapy. Urinary Mg decreased in parallel with serum levels in all patients (P <.005). The peripheral blood mononuclear cell Mg content per cell increased within 24 hours of treatment (P <.005). The magnitude of these changes was similar during the first week of treatment for patients receiving intravenous or subcutaneous administration of IL-2. During IL-2 therapy, lymphocyte Mg increases coincident with serum Mg depletion. Mg availability may have functional implications for lymphocyte proliferation and integrin function.

Adult↗