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Dive into the research topics where Nathaniel A. Brown is active.

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Featured researches published by Nathaniel A. Brown.


Annals of Internal Medicine | 1988

Chronic Fatigue Syndrome: A Working Case Definition

Gary P. Holmes; Jonathan E. Kaplan; Nelson M. Gantz; Anthony L. Komaroff; Lawrence B. Schonberger; Straus Se; James F. Jones; Richard E. Dubois; Charlotte Cunningham-Rundles; Savita Pahwa; Giovanna Tosato; Leonard S. Zegans; David T. Purtilo; Nathaniel A. Brown; Robert T. Schooley; Irena Brus

The chronic Epstein-Barr virus syndrome is a poorly defined symptom complex characterized primarily by chronic or recurrent debilitating fatigue and various combinations of other symptoms, including sore throat, lymph node pain and tenderness, headache, myalgia, and arthralgias. Although the syndrome has received recent attention, and has been diagnosed in many patients, the chronic Epstein-Barr virus syndrome has not been defined consistently. Despite the name of the syndrome, both the diagnostic value of Epstein-Barr virus serologic tests and the proposed causal relationship between Epstein-Barr virus infection and patients who have been diagnosed with the chronic Epstein-Barr virus syndrome remain doubtful. We propose a new name for the chronic Epstein-Barr virus syndrome--the chronic fatigue syndrome--that more accurately describes this symptom complex as a syndrome of unknown cause characterized primarily by chronic fatigue. We also present a working definition for the chronic fatigue syndrome designed to improve the comparability and reproducibility of clinical research and epidemiologic studies, and to provide a rational basis for evaluating patients who have chronic fatigue of undetermined cause.


The New England Journal of Medicine | 1999

Lamivudine as Initial Treatment for Chronic Hepatitis B in the United States

Jules L. Dienstag; Eugene R. Schiff; Teresa L. Wright; Robert P. Perrillo; Hie Won L. Hann; Zachary D. Goodman; Lynn Crowther; Lynn D. Condreay; Mary Woessner; Marc Rubin; Nathaniel A. Brown

BACKGROUND AND METHODS Although the nucleoside analogue lamivudine has shown promise in patients with chronic hepatitis B, long-term data on patients from the United States are lacking. We randomly assigned previously untreated patients with chronic hepatitis B to receive either 100 mg of oral lamivudine or placebo daily for 52 weeks. We then followed them for an additional 16 weeks to evaluate post-treatment safety and the durability of responses. The primary end point with respect to efficacy was a reduction of at least 2 points in the score on the Histologic Activity Index. On this scale, scores can range from 0 (normal) to 22 (most severe abnormalities). RESULTS Of the 143 randomized patients, 137 were included in the efficacy analysis: 66 in the lamivudine group and 71 in the placebo group. The other six patients were excluded at the base-line visit because of the absence of a documented history of hepatitis B surface antigen for at least six months. After 52 weeks of treatment, lamivudine recipients were more likely than placebo recipients to have a histologic response (52 percent vs. 23 percent, P<0.001), loss of hepatitis B e antigen (HBeAg) in serum (32 percent vs. 11 percent, P=0.003), sustained suppression of serum hepatitis B virus (HBV) DNA to undetectable levels (44 percent vs. 16 percent, P<0.001), and sustained normalization of serum alanine aminotransferase levels (41 percent vs. 7 percent, P<0.001), and they were less likely to have increased hepatic fibrosis (5 percent vs. 20 percent, P=0.01). Lamivudine recipients were also more likely to undergo HBeAg seroconversion, defined as the loss of HBeAg, undetectable levels of serum HBV DNA, and the appearance of antibodies against HBeAg (17 percent vs. 6 percent, P=0.04). HBeAg responses persisted in most patients for 16 weeks after the discontinuation of treatment. Lamivudine was well tolerated. Self-limited post-treatment elevations in serum alanine aminotransferase were more common in lamivudine recipients: 25 percent had serum alanine aminotransferase levels that were at least three times base-line levels, as compared with 8 percent of placebo recipients (P=0.01). The clinical condition of all patients remained stable during the study. CONCLUSIONS In U.S. patients with previously untreated chronic hepatitis B, one year of lamivudine therapy had favorable effects on histologic, virologic, and biochemical features of the disease and was well tolerated. HBeAg responses were generally sustained after treatment.


Clinical Infectious Diseases | 2003

Prevalence and Clinical Correlates of YMDD Variants during Lamivudine Therapy for Patients with Chronic Hepatitis B

Ching-Lung Lai; Jules L. Dienstag; Eugene R. Schiff; Nancy Leung; Mark Atkins; Christine M. Hunt; Nathaniel A. Brown; Mary Woessner; Richard Boehme; Lynn D. Condreay

YMDD variants of hepatitis B virus (HBV) emerge in some patients with chronic hepatitis B who receive lamivudine. YMDD variants were examined in 794 patients in 4 controlled studies of 1 years duration. The long-term effects of YMDD variants were examined in a subset of patients treated up to 4 years. YMDD variants were detected by polymerase chain reaction (PCR) and restriction fragment-length polymorphism assays. After 1 year, YMDD variants were detected in 81 (24%) of 335 patients. In these patients, the median serum HBV DNA concentration at 1 year was <20% of the baseline level, and serum alanine transaminase (ALT) levels and liver histologic findings had significantly improved. In patients with YMDD variants who were treated for up to 4 years, median HBV DNA and ALT levels showed improvements. Sex, baseline body mass index, and HBV DNA level were associated with emergence of YMDD variants. Patients with YMDD variants losing clinical response with a significant increase in the HBV DNA and ALT levels may require additional therapy.


Gastroenterology | 2009

2-Year GLOBE Trial Results: Telbivudine Is Superior to Lamivudine in Patients With Chronic Hepatitis B

Yun Fan Liaw; Edward Gane; Nancy Leung; Stefan Zeuzem; Yuming Wang; Ching-Lung Lai; E. Jenny Heathcote; Michael P. Manns; Natalie Bzowej; Junqi Niu; Steven Han; Seong Gyu Hwang; Yilmaz Cakaloglu; Myron J. Tong; George V. Papatheodoridis; Yagang Chen; Nathaniel A. Brown; Efsevia Albanis; Karin Galil; Nikolai V. Naoumov

BACKGROUND & AIMS The GLOBE trial has compared the efficacy and safety of telbivudine versus lamivudine treatment over 2 years in patients with chronic hepatitis B. METHODS Hepatitis B e antigen (HBeAg)-positive (n = 921) and HBeAg-negative (n = 446) patients received telbivudine or lamivudine once daily for 104 weeks. The primary outcome, assessed in the intent-to-treat population, was therapeutic response (hepatitis B virus DNA <5 log(10) copies/mL and either HBeAg loss or normalization of alanine aminotransferase [ALT] level). RESULTS The therapeutic response to telbivudine was superior to that of lamivudine in HBeAg-positive (63% vs 48%; P < .001) and HBeAg-negative (78% vs 66%; P = .007) patients. HBeAg-positive patients given telbivudine also had better outcomes compared with lamivudine in terms of nondetectable viremia (< 300 copies/mL) at 55.6% versus 38.5% (P < .001), HBeAg loss at 35.2% versus 29.2% (P = .056), and viral resistance at 25.1% versus 39.5% (P < .001). Hepatitis B e antigen seroconversion was 29.6% versus 24.7% (P = .095) in all patients and 36% versus 27% (P = .022) in patients with baseline ALT level > or = 2 times normal. Telbivudine-treated HBeAg-negative patients showed higher rates of nondetectable viremia compared with lamivudine at 82.0% versus 56.7% (P < .001) and less resistance at 10.8% versus 25.9% (P < .001). Adverse events occurred with similar frequency, whereas grade 3/4 increases in creatine kinase levels were more common in patients given telbivudine (12.9% vs 4.1%, P < .001). Multivariate logistic regression analyses identified telbivudine treatment, among other variables, as an independent predictor of better week 104 outcomes. CONCLUSIONS Telbivudine is superior to lamivudine in treating patients with chronic hepatitis B over a 2-year period.


The Lancet | 1997

Hepatitis-B-virus resistance to lamivudine given for recurrent infection after orthotopic liver transplantation

Maria Bartholomew; Robert W Jansen; Lennox J. Jeffers; K. Rajender Reddy; Lance C. Johnson; Hartwig Bunzendahl; Lynn D. Condreay; Andreas G. Tzakis; Eugene R. Schiff; Nathaniel A. Brown

BACKGROUND Orthotopic liver transplantation for end-stage hepatitis-B-virus (HBV) infection is commonly complicated by recurrence of HBV. Lamivudine, a cytosine nucleoside analogue, has been shown to suppress HBV infection. We report the development of resistance to lamivudine in three patients who underwent transplantation for end-stage liver disease secondary to hepatitis B. METHODS Two of the patients received lamivudine for recurrent HBV infection after transplantation, whereas the third patient began treatment 1 month before transplantation in an attempt to prevent HBV recurrence after transplantation. The three patients initially responded well to treatment, but viral recurrence occurred after 9-10 months of treatment in all patients. HBV DNA was amplified from serum and sequenced through a conserved polymerase domain-the tyrosine, methionine, aspartate, aspartate (YMDD) locus. We assessed the susceptibility of HBV to lamivudine by infecting primary human hepatocytes with serum taken before the start of treatment and after recurrence in varying concentrations of lamivudine. FINDINGS DNA sequencing showed a common mutation within the YMDD locus of the HBV polymerase gene in all patients during lamivudine treatment. In hepatocyte cultures infected with pretreatment serum, HBV DNA concentrations were reduced to less than 6% of those in control cultures by addition of lamivudine in concentrations as low as 0.03 mumol/L. By contrast, in cultures treated with serum taken after recurrence, HBV DNA concentrations did not fall below 20% of control values, even with lamivudine at 30 mumol/L. INTERPRETATION Resistance to lamivudine has been reported in HIV patients with mutations in the YMDD locus of the polymerase gene. Our findings indicate a common mechanism of lamivudine resistance for HIV and HBV that involves similar point mutations in homologous domains of the viral polymerases.


Annals of Internal Medicine | 2007

Treatment of Hepatitis B e Antigen-Positive Chronic Hepatitis with Telbivudine or Adefovir: A Randomized Trial

Henry Lik-Yuen Chan; E. Jenny Heathcote; Patrick Marcellin; Ching-Lung Lai; Mong Cho; Young Myoung Moon; You-Chen Chao; Robert P. Myers; Gerald Y. Minuk; Lennox J. Jeffers; William Sievert; Natalie Bzowej; George Harb; Ralf Kaiser; Xin-Jian Qiao; Nathaniel A. Brown

BACKGROUND The efficacy of nucleoside and nucleotide analogues for hepatitis B has been linked to the magnitude and durability of hepatitis B virus (HBV) suppression. OBJECTIVE To compare the antiviral efficacy of telbivudine and adefovir dipivoxil, and the effects of switching from adefovir to telbivudine, in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B. DESIGN Randomized, controlled, open-label trial. SETTING 16 outpatient clinics. PATIENTS 135 treatment-naive, HBeAg-positive adults with chronic hepatitis B. INTERVENTION Patients were randomly assigned in a 1:1:1 ratio to 52 weeks of telbivudine (group A) or adefovir (group B), or 24 weeks of adefovir and then telbivudine for the remaining 28 weeks (group C). One hundred thirty-one patients completed 52 weeks of treatment. MEASUREMENTS The primary efficacy comparison was serum HBV DNA reduction at week 24, with a secondary comparison at week 52. RESULTS At week 24, mean HBV DNA reduction was greater in group A than in pooled groups B and C (-6.30 vs. -4.97 log10 copies/mL; difference, -1.33 log10 copies/mL [95% CI, -1.99 to -0.66 log(10) copies/mL]; P < 0.001), and more patients in group A were polymerase chain reaction-negative (39% vs. 12%; odds ratio, 4.46 [CI, 1.86 to 10.72]; P = 0.001). At week 52, the mean residual HBV DNA level was lower in group A and group C than in group B (3.01 log10 copies/mL [group A] and 3.02 log10 copies/mL [group C] vs. 4.00 log10 copies/mL [group B]; difference, -0.99 log10 copies/mL [CI, -1.67 to -0.32 log10 copies/mL] and -0.98 log10 copies/mL [CI, -1.64 to -0.32 log10 copies/mL]; P = 0.004). Adverse events were similar across groups; the most common were upper respiratory symptoms, headache, back pain, and diarrhea. LIMITATIONS The trial was open-label and was not of sufficient size or duration to compare clinical outcomes and long-term efficacy. CONCLUSION Telbivudine demonstrated greater and more consistent HBV DNA suppression than adefovir after 24 weeks of treatment. After 52 weeks, HBV DNA suppression was greater in patients who had received continuous telbivudine or were switched to telbivudine after 24 weeks than in those who received continuous adefovir.


Journal of Hepatology | 2001

Decreasing fibrogenesis: an immunohistochemical study of paired liver biopsies following lamivudine therapy for chronic hepatitis B

Young Oh Kweon; Zachary D. Goodman; Jules L. Dienstag; Eugene R. Schiff; Nathaniel A. Brown; Elmar Burkhardt; Robert Schoonhoven; David A. Brenner; Michael W. Fried

BACKGROUND Activation of hepatic stellate cells is the earliest step in fibrogenesis. Alpha-smooth muscle actin (alpha-SMA), expressed by activated hepatic stellate cells, and C-terminal procollagen alpha1(III) propeptide (PIIICP) are early markers of fibrogenesis and should precede fibrosis. AIM Determine if suppression of hepatitis B virus replication with lamivudine would decrease fibrogenesis as measured by immunohistochemical markers. METHODS Paired liver biopsies from patients with hepatitis B before and after therapy with lamivudine (n=47) or placebo (n=33) were studied. alpha-SMA and PIIICP were detected in paraffin-embedded tissue by immunohistochemistry and quantified in a blinded manner by video imaging analysis. RESULTS Liver biopsies from patients treated with lamivudine showed a significant decrease in alpha-SMA expression (1.06+/-0.23 vs. 0.58+/-0.11, pre vs. post, P<0.05). Placebo recipients had increased levels of alpha-SMA (0.82+/-0.14 vs. 1.32+/-0.21, P<0.05). PIIICP was similarly decreased after lamivudine. Among subjects whose Histologic Activity Index fibrosis score was unchanged or worsened, the mean change in alpha-SMA expression was significantly decreased in the lamivudine group compared with placebo. CONCLUSIONS Lamivudine decreased markers of hepatic stellate cell activation and collagen synthesis. Immunohistochemical techniques are sensitive for assessing fibrogenesis and will be useful in trials of antiviral and antifibrotic agents.


Hepatology | 2007

Telbivudine versus lamivudine in Chinese patients with chronic hepatitis B: Results at 1 year of a randomized, double-blind trial.

Jinlin Hou; You-Kuan Yin; Dao-Zhen Xu; Deming Tan; Junqi Niu; X.J. Zhou; Yuming Wang; Limin Zhu; Yongwen He; Hong Ren; Mo-Bin Wan; Chengwei Chen; Shan-Ming Wu; Yagang Chen; Jiazhang Xu; Qinhuan Wang; Lai Wei; George C. Chao; Barbara Fielman Constance; George Harb; Nathaniel A. Brown; Jidong Jia

Chronic hepatitis B and its life‐threatening sequelae are highly prevalent in China. There is a need for effective new therapies to suppress hepatitis B virus (HBV) replication and ameliorate liver disease. In this study, we compared the efficacy of telbivudine, a nucleoside analogue, with lamivudine in Chinese patients. In this phase III, double‐blind, multicenter trial conducted in China, 332 patients with compensated hepatitis B e antigen (HBeAg)–positive or HBeAg‐negative chronic hepatitis B were randomly assigned to treatment with 600 mg of telbivudine or 100 mg of lamivudine daily for 104 weeks. The primary efficacy endpoint was reduction in serum HBV DNA levels at week 52 of treatment. Secondary endpoints included clearance of HBV DNA to undetectable levels, HBeAg loss and seroconversion, therapeutic response, and alanine aminotransferase (ALT) normalization. Viral resistance and safety were assessed. At week 52, among 290 HBeAg‐positive patients, mean reductions of serum HBV DNA were significantly greater in telbivudine recipients than lamivudine recipients (6.3 log10 versus 5.5 log10, P < 0.001), and HBV DNA was polymerase chain reaction–negative in significantly more telbivudine recipients than lamivudine recipients (67% versus 38%, P < 0.001). ALT normalization (87% versus 75%, P = 0.007), therapeutic response (85% versus 62%, P = 0.001), and HBeAg loss (31% versus 20%, P = 0.047) were also significantly more common in the telbivudine group. Treatment effects showed similar patterns in the smaller HBeAg‐negative group (n = 42). Viral resistance in telbivudine recipients was approximately half that observed with lamivudine; however, this difference was not statistically significant. Clinical adverse events were similar in the two treatment groups. Conclusion: In Chinese patients with chronic hepatitis B, telbivudine treatment for 52 weeks provided greater antiviral and clinical efficacy than lamivudine, with less resistance. (HEPATOLOGY 2007.)


The New England Journal of Medicine | 1980

Diffuse Polyclonal B-Cell Lymphoma during Primary Infection with Epstein–Barr Virus

James Robinson; Nathaniel A. Brown; Warren A. Andiman; Karen Halliday; Uta Francke; Marie Robert; Maria Andersson-Anvret; Dorothy M. Horstmann; George Miller

ALTHOUGH most primary infections with Epstein–Barr virus (EBV) in childhood are silent or associated with mild nonspecific illness, a few are recognized as infectious mononucleosis, a lymphoprolife...


The Journal of Infectious Diseases | 1999

Quantitation of hepatitis B viremia and emergence of YMDD variants in patients with chronic hepatitis B treated with lamivudine

Josee Gauthier; Eric J. Bourne; Michael W. Lutz; Lynn Crowther; Jules L. Dienstag; Nathaniel A. Brown; Lynn D. Condreay

Hepatitis B viremia and emergence of hepatitis B virus (HBV) YMDD variants with reduced susceptibility to lamivudine were analyzed in patient sera from a phase II study of extended lamivudine therapy. Within 12 weeks, all patients exhibited a marked virologic response to lamivudine: >99% reduction (median 5 log decrease) in serum HBV DNA levels. Virus remained at >104 genomes/mL in 11 patients and decreased to <104 genomes/mL in the remaining 12 patients. In 10 patients, detectable YMDD variants emerged during the course of treatment. Six patients, including 3 with YMDD variants, experienced hepatitis B e antigen seroconversion while on lamivudine therapy or soon after its discontinuation. No patients with HBV DNA levels >104 genomes/mL seroconverted. Thus, patients who respond to lamivudine therapy with dramatic reductions in viral DNA level (to <104 genomes/mL) appear more likely to seroconvert than patients who do not achieve this level of HBV clearance.

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Robert P. Perrillo

Baylor University Medical Center

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Edward Gane

Auckland City Hospital

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Marc Rubin

National Institutes of Health

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