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Featured researches published by Silvina Levis.


The New England Journal of Medicine | 1997

Comparison of administration of recombinant human thyrotropin with withdrawal of thyroid hormone for radioactive iodine scanning in patients with thyroid carcinoma.

Paul W. Ladenson; Lewis E. Braverman; Ernest L. Mazzaferri; Françoise Brucker-Davis; David S. Cooper; Jeffrey R. Garber; Fredric E. Wondisford; Terry F. Davies; Leslie J. DeGroot; Gilbert H. Daniels; Douglas S. Ross; Bruce D. Weintraub; Ian D. Hay; Silvina Levis; James C. Reynolds; Jacob Robbins; David V. Becker; Ralph R. Cavalieri; Harry R. Maxon; Kevin McEllin; Richard Moscicki

BACKGROUND To detect recurrent disease in patients who have had differentiated thyroid cancer, periodic withdrawal of thyroid hormone therapy may be required to raise serum thyrotropin concentrations to stimulate thyroid tissue so that radioiodine (iodine-131) scanning can be performed. However, withdrawal of thyroid hormone therapy causes hypothyroidism. Administration of recombinant human thyrotropin stimulates thyroid tissue without requiring the discontinuation of thyroid hormone therapy. METHODS One hundred twenty-seven patients with thyroid cancer underwent whole-body radioiodine scanning by two techniques: first after receiving two doses of thyrotropin while thyroid hormone therapy was continued, and second after the withdrawal of thyroid hormone therapy. The scans were evaluated by reviewers unaware of the conditions of scanning. The serum thyroglobulin concentrations and the prevalence of symptoms of hypothyroidism and mood disorders were also determined. RESULTS Sixty-two of the 127 patients had positive whole-body radioiodine scans by one or both techniques. The scans obtained after stimulation with thyrotropin were equivalent to the scans obtained after withdrawal of thyroid hormone in 41 of these patients (66 percent), superior in 3 (5 percent), and inferior in 18 (29 percent). When the 65 patients with concordant negative scans were included, the two scans were equivalent in 106 patients (83 percent). Eight patients (13 percent of those with at least one positive scan) were treated with radioiodine on the basis of superior scans done after withdrawal of thyroid hormone. Serum thyroglobulin concentrations increased in 15 of 35 tested patients: 14 after withdrawal of thyroid hormone and 13 after administration of thyrotropin. Patients had more symptoms of hypothyroidism (P<0.001) and dysphoric mood states (P<0.001) after withdrawal of thyroid hormone than after administration of thyrotropin. CONCLUSIONS Thyrotropin stimulates radioiodine uptake for scanning in patients with thyroid cancer, but the sensitivity of scanning after the administration of thyrotropin is less than that after the withdrawal of thyroid hormone. Thyrotropin scanning is associated with fewer symptoms and dysphoric mood states.


Journal of Translational Medicine | 2009

Plasma cytokines in women with chronic fatigue syndrome

Mary A Fletcher; Zachary Barnes; Silvina Levis; Nancy G. Klimas

BackgroundChronic Fatigue Syndrome (CFS) studies from our laboratory and others have described cytokine abnormalities. Other studies reported no difference between CFS and controls. However, methodologies varied widely and few studies measured more than 4 or 5 cytokines. Multiplex technology permits the determination of cytokines for a large panel of cytokines simultaneously with high sensitivity and with only 30 ul of plasma per sample. No widely accepted laboratory test or marker is available for the diagnosis or prognosis of CFS. This study screened plasma factors to identify circulating biomarkers associated with CFS.MethodsCytokines were measured in plasma from female CFS cases and female healthy controls. Multiplex technology provided profiles of 16 plasma factors including the pro -inflammatory cytokines: tumor necrosis factor α (TNFα), lymphotoxin α (LTα), interleukin (IL) - IL-Iα, IL-1β, IL-6; TH1 cytokines: interferon γ (IFNγ), IL-12p70, IL-2, IL-15; TH2: IL-4, IL-5; TH17 cytokines, IL-17 and IL-23; anti-inflammatory cytokines IL-10, IL-13; the inflammatory mediator and neutrophil attracting chemokine IL-8 (CXCL8). Analysis by receiver operating characteristic (ROC) curve assessed the biomarker potential of each cytokine.ResultsThe following cytokines were elevated in CFS compared to controls: LTα, IL-1α, IL-1β, IL-4, IL-5, IL-6 and IL-12. The following cytokines were decreased in CFS: IL-8, IL-13 and IL-15. The following cytokines were not different: TNFα, IFNγ, IL-2, IL-10, IL-23 and IL-17. Applying (ROC) curve analyses, areas under the curves (AUC) for IL-5 (0. 84), LTα (0.77), IL-4 (0.77), IL-12 (0.76) indicated good biomarker potential. The AUC of IL-6 (0.73), IL-15 (0.73), IL-8 (0.69), IL-13 (0.68) IL-1α (0.62), IL-1β (0.62) showed fair potential as biomarkers.ConclusionCytokine abnormalities are common in CFS. In this study, 10 of 16 cytokines examined showed good to fair promise as biomarkers. However, the cytokine changes observed are likely to more indicative of immune activation and inflammation, rather than specific for CFS. As such, they are targets for herapeutic strategies. Newer techniques allow evaluation of large panels of cytokines in a cost effective fashion.


JAMA Internal Medicine | 2011

Soy isoflavones in the prevention of menopausal bone loss and menopausal symptoms: a randomized, double-blind trial.

Silvina Levis; Nancy Strickman-Stein; Parvin Ganjei-Azar; Ping Xu; Daniel R. Doerge; Jeffrey P. Krischer

BACKGROUND Concerns regarding the risk of estrogen replacement have resulted in a significant increase in the use of soy products by menopausal women who, despite the lack of evidence of the efficacy of such products, seek alternatives to menopausal hormone therapy. Our goal was to determine the efficacy of soy isoflavone tablets in preventing bone loss and menopausal symptoms. METHODS The study design was a single-center, randomized, placebo-controlled, double-blind clinical trial conducted from July 1, 2004, through March 31, 2009. Women aged 45 to 60 years within 5 years of menopause and with a bone mineral density T score of -2.0 or higher in the lumbar spine or total hip were randomly assigned, in equal proportions, to receive daily soy isoflavone tablets, 200 mg, or placebo. The primary outcome was changes in bone mineral density in the lumbar spine, total hip, and femoral neck at the 2-year follow-up. Secondary outcomes included changes in menopausal symptoms, vaginal cytologic characteristics, N -telopeptide of type I bone collagen, lipids, and thyroid function. RESULTS After 2 years, no significant differences were found between the participants receiving soy tablets (n = 122) and those receiving placebo (n = 126) regarding changes in bone mineral density in the spine (-2.0% and -2.3%, respectively), the total hip (-1.2% and -1.4%, respectively), or the femoral neck (-2.2% and -2.1%, respectively). A significantly larger proportion of participants in the soy group experienced hot flashes and constipation compared with the control group. No significant differences were found between groups in other outcomes. CONCLUSIONS In this population, the daily administration of tablets containing 200 mg of soy isoflavones for 2 years did not prevent bone loss or menopausal symptoms. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00076050.


PLOS ONE | 2010

Biomarkers in Chronic Fatigue Syndrome: Evaluation of Natural Killer Cell Function and Dipeptidyl Peptidase IV/CD26

Mary A Fletcher; Xiao R. Zeng; Kevin Maher; Silvina Levis; Barry E. Hurwitz; Michael H. Antoni; Gordon Broderick; Nancy G. Klimas

Background Chronic Fatigue Syndrome (CFS) studies from our laboratory and others described decreased natural killer cell cytotoxicity (NKCC) and elevated proportion of lymphocytes expressing the activation marker, dipeptidyl peptidase IV (DPPIV) also known as CD26. However, neither these assays nor other laboratory tests are widely accepted for the diagnosis or prognosis of CFS. This study sought to determine if NKCC or DPPIV/CD26 have diagnostic accuracy for CFS. Methods/Results Subjects included female and male CFS cases and healthy controls. NK cell function was measured with a bioassay, using K562 cells and 51Cr release. Lymphocyte associated DPPIV/CD26 was assayed by qualitative and quantitative flow cytometry. Serum DPPIV/CD26 was measured by ELISA. Analysis by receiver operating characteristic (ROC) curve assessed biomarker potential. Cytotoxic function of NK cells for 176 CFS subjects was significantly lower than in the 230 controls. According to ROC analysis, NKCC was a good predictor of CFS status. There was no significant difference in NK cell counts between cases and controls. Percent CD2+ lymphocytes (T cells and NK cells) positive for DPPIV/C26 was elevated in CFS cases, but there was a decrease in the number of molecules (rMol) of DPPIV/C26 expressed on T cells and NK cells and a decrease in the soluble form of the enzyme in serum. Analyses by ROC curves indicated that all three measurements of DPPIV/CD26 demonstrated potential as biomarkers for CFS. None of the DPPIV/C26 assays were significantly correlated with NKCC. Conclusions By ROC analysis, NKCC and three methods of measuring DPPIV/C26 examined in this study had potential as biomarkers for CFS. Of these, NKCC, %CD2+CD26+ lymphocytes and rMol CD26/CD2+ lymphocyte, required flow cytometry, fresh blood and access to a high complexity laboratory. Soluble DPPIV/C26 in serum is done with a standard ELISA assay, or with other soluble factors in a multiplex type of ELISA. Dipeptidyl peptidase IV on lymphocytes or in serum was not predictive of NKCC suggesting that these should be considered as non-redundant biomarkers. Abnormalities in DPPIV/CD26 and in NK cell function have particular relevance to the possible role of infection in the initiation and/or the persistence of CFS.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2008

Unequal burden of head and neck cancer in the United States

W. Jarrard Goodwin; Giovana R. Thomas; Dorothy F. Parker; Debbie Joseph; Silvina Levis; Elizabeth J. Franzmann; Charles Anello; Jennifer J. Hu

Black Americans are adversely affected by many types of malignancies.


The Journal of Steroid Biochemistry and Molecular Biology | 2007

Outdoor exercise reduces the risk of hypovitaminosis D in the obese

Hermes Florez; Ramon Martinez; Walid Chacra; Nancy Strickman-Stein; Silvina Levis

Obesity is associated with lower levels of serum 25-hydroxyvitamin D (25(OH)D). Obese individuals might need higher doses of vitamin D supplementation than the general population. In this cross-sectional study, associations between 25(OH)D serum levels, body mass index (BMI), and outdoor exercise were assessed in a population of 291 ambulatory patients attending the Osteoporosis Center at the University of Miami, mean age 62+/-13.48 years. Obesity was defined as BMI> or =30 kg/m(2) and hypovitaminosis D as 25(OH)D< or =30 ng/ml. Overall, prevalence of obesity was 14.1% and of hypovitaminosis D was 42.4%. Among Hispanics, there was a significantly higher prevalence of hypovitaminosis D in obese (63.2%) compared to non-obese individuals (35.8%). Outdoor exercise had a significant effect on the prevalence of hypovitaminosis D in Hispanics, with a lower prevalence in those performing outdoor exercise (24.1%) compared to those who did not (47.9%). After adjusting for age, gender, and ethnicity, those reporting outdoor exercise were 47% less likely to have hypovitaminosis D, while those with obesity had more than twice the risk. Since outdoor exercise may protect overweight individuals from hypovitaminosis D, prevention programs involving higher doses of vitamin D and/or outdoor exercise may result in additional metabolic and functional benefits in this population.


Journal of the American Geriatrics Society | 2002

Alendronate Reduces the Risk of Multiple Symptomatic Fractures: Results from the Fracture Intervention Trial

Silvina Levis; Sara A. Quandt; Desmond E. Thompson; Jean C. Scott; Diane L. Schneider; Philip D. Ross; Dennis M. Black; Shailaja Suryawanshi; Marc C. Hochberg; John Yates

To evaluate the effect of alendronate on the occurrence rate of multiple symptomatic fractures and on the risk of multiple symptomatic fractures (likelihood of having more than one fracture diagnosed because of the symptoms the fractures caused over the study period) among women with osteoporosis.


Journal of Nutrition Health & Aging | 2008

Hypovitaminosis D in the elderly: From bone to brain

E. P. Cherniack; Hermes Florez; Bernard A. Roos; Bruce R. Troen; Silvina Levis

ConclusionThere is a growing consensus that vitamin D recommended daily intakes for the elderly are far too low, and that all individuals should take as much vitamin D as needed to raise levels to between 32 to 40 ng/ml (80 to 100 nmol/L) (5, 108, 109). Supplementation will likely be necessary in most elderly, since according to current lifestyles, diet and sunlight alone are inadequate sources of vitamin D (17). We believe that to raise and maintain 25(OH) vitamin D levels at a minimum of 32 ng/ml (80 nmol/L), most elderly will require at least 2,000 IU of cholecalciferol per day.But many questions remain. Are other biological markers preferable to 25(OH) vitamin D to assess repletion? Do the current estimates of optimal serum levels provide health benefits for all conditions, or do optimal vitamin D levels differ depending on the target tissue? How much vitamin D, cholecalciferol, or ergocalciferol, should be given to maintain these levels? What are the molecular mechanisms by which vitamin D influences health and disease?Cross-sectional studies have suggested that low vitamin D levels not only predict nursing home admission but also are associated with increased mortality (1, 2). Further knowledge of the mechanisms of vitamin D action and prospective clinical trials designed to determine if supplementation resulting in vitamin D levels higher than those shown to reduce the risk of falls and fractures is also effective in reducing the burden of various medical conditions could help validate a cost-effective intervention that will provide greater quality of life and longevity and have a major public health impact.


Menopause | 2008

Earlier age at menopause, work, and tobacco smoke exposure.

Lora E. Fleming; Silvina Levis; William G. LeBlanc; Noella A. Dietz; Kristopher L. Arheart; James D. Wilkinson; John D. Clark; Berrin Serdar; Evelyn P. Davila; David J. Lee

Objective:Earlier age at menopause onset has been associated with increased all-cause, cardiovascular, and cancer mortality risks. The risk of earlier age at menopause associated with primary and secondary tobacco smoke exposure was assessed. Design:This was a cross-sectional study using a nationally representative sample of US women. A total of 7,596 women (representing an estimated 79 million US women) from the National Health and Nutrition Examination Survey III were asked time since last menstrual period, occupation, and tobacco use (including home and workplace second-hand smoke [SHS] exposure). Blood cotinine and follicle-stimulating hormone levels were assessed. Logistic regressions for the odds of earlier age at menopause, stratified on race/ethnicity in women 25 to 50 years of age and adjusted for survey design, were controlled for age, body mass index, education, tobacco smoke exposure, and occupation. Results:Among 5,029 US women older than 25 years with complete data, earlier age at menopause was found among all smokers and among service and manufacturing industry sector workers. Among women age 25 to 50 years, there was an increased risk of earlier age at menopause with both primary smoking and SHS exposure, particularly among black women. Conclusions:Primary tobacco use and SHS exposure were associated with increased odds of earlier age at menopause in a representative sample of US women. Earlier age at menopause was found for some women worker groups with greater potential occupational SHS exposure. Thus, control of SHS exposure in the workplace may decrease the risk of mortality and morbidity associated with earlier age at menopause in US women workers.


Behavioral and Brain Functions | 2010

Plasma neuropeptide Y: a biomarker for symptom severity in chronic fatigue syndrome

Mary A Fletcher; Martin Rosenthal; Michael H. Antoni; Gail Ironson; Xiao R. Zeng; Zachary Barnes; Jeanna M. Harvey; Barry E. Hurwitz; Silvina Levis; Gordon Broderick; Nancy G. Klimas

BackgroundChronic fatigue syndrome (CFS) is a complex, multi-symptom illness with a multisystem pathogenesis involving alterations in the nervous, endocrine and immune systems.Abnormalities in stress responses have been identified as potential triggers or mediators of CFS symptoms. This study focused on the stress mediator neuropeptide Y (NPY). We hypothesized that NPY would be a useful biomarker for CFS.MethodsThe CFS patients (n = 93) were from the Chronic Fatigue and Related Disorders Clinic at the University of Miami and met the 1994 case definition of Fukuda and colleagues. Healthy sedentary controls (n = 100)) were from NIH or VA funded studies. Another fatiguing, multi-symptom illness, Gulf War Illness (GWI), was also compared to CFS. We measured NPY in plasma using a radioimmunoassay (RIA). Psychometric measures, available for a subset of CFS patients included: Perceived Stress Scale, Profile of Mood States, ATQ Positive & Negative Self-Talk Scores, the COPE, the Beck Depression Inventory, Fatigue Symptom Inventory, Cognitive Capacity Screening Examination, Medical Outcomes Survey Short Form-36, and the Quality of Life Scale.ResultsPlasma NPY was elevated in CFS subjects, compared to controls (p = .000) and to GWI cases (p = .000). Receiver operating characteristics (ROC) curve analyses indicated that the predictive ability of plasma NPY to distinguish CFS patients from healthy controls and from GWI was significantly better than chance alone. In 42 patients with CFS, plasma NPY had significant correlations (<0.05) with perceived stress, depression, anger/hostility, confusion, negative thoughts, positive thoughts, general health, and cognitive status. In each case the correlation (+ or -) was in the anticipated direction.ConclusionsThis study is the first in the CFS literature to report that plasma NPY is elevated compared to healthy controls and to a fatigued comparison group, GWI patients. The significant correlations of NPY with stress, negative mood, general health, depression and cognitive function strongly suggest that this peptide be considered as a biomarker to distinguish subsets of CFS.

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Daniel R. Doerge

Food and Drug Administration

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