PubMed Health⌕ Search

Biomedical subjects

Amy Lin

Publications and source records attributed to Amy Lin.

15 recordsLinked to original sources
PubMed2006

Hemodynamics in the mouse aortic arch as assessed by MRI, ultrasound, and numerical modeling.

Mice are widely used to study arterial disease in humans, and the pathogenesis of arterial diseases is known to be strongly influenced by hemodynamic factors. It is, therefore, of interest to characterize the hemodynamic environment in the mouse arterial tree. Previous measurements have suggested that many relevant hemodynamic variables are similar between the mouse and the human. Here we use a combination of Doppler ultrasound and MRI measurements, coupled with numerical modeling techniques, to characterize the hemodynamic environment in the mouse aortic arch at high spatial resolution. We find that the hemodynamically induced stresses on arterial endothelial cells are much larger in magnitude and more spatially uniform in the mouse than in the human, an effect that can be explained by fluid mechanical scaling principles. This surprising finding seems to be at variance with currently accepted models of the role of hemodynamics in atherogenesis and the known distribution of atheromatous lesions in mice.

Animals↗
PubMed2006

Low-dose warfarin does not decrease the rate of thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy, radiation, and erythropoeitin.

OBJECTIVES: We had previously reported an association between the use of recombinant human erythropoietin (rHuEPO) and thrombosis in patients with cervix and vulvo-vaginal cancer treated with chemotherapy and radiation. We hypothesized that low-dose warfarin would be effective prevention for thromboembolic events in this setting. METHODS: A retrospective analysis of patients with cervical or vulvo-vaginal carcinoma receiving chemoradiation and rHuEpo was performed. Thirty-two patients received rHuEpo alone, and 24 received warfarin (1-2 mg) and rHuEpo. The primary endpoint was objectively proven symptomatic venous thrombosis. RESULTS: There was no difference in the baseline characteristics (e.g. age, stage, body mass index, mean and peak hemoglobin, WBC and platelet counts, and number of transfusions) between these two groups. The rate of thrombosis also was not statistically different (P = 0.62). Nine of 24 patients had a symptomatic deep vein thrombosis (DVT) while receiving warfarin compared to 10 of 32 patients not on warfarin. There was no difference between the two groups in the percentage of patients with upper extremity DVT (P = 0.83) or lower extremity DVT (P = 0.64). CONCLUSION: Daily low-dose warfarin did not alter the incidence of symptomatic DVT in patients with cervical or vulvo-vaginal cancer who received rHuEpo in conjunction with chemoradiation.

Anticoagulants↗
PubMed2006

Accuracy Evaluation for Region Centroid-Based Registration of Fluorescent CLSM Imagery.

We present an accuracy evaluation of a semi-automatic registration technique for 3D volume reconstruction from fluorescent confocal laser scanning microscope (CLSM) imagery. The presented semi-automatic method is designed based on our observations that (a) an accurate point selection is much harder than an accurate region (segment) selection for a human, (b) a centroid selection of any region is less accurate by a human than by a computer, and (c) registration based on structural shape of a region rather than based on intensity-defined point is more robust to noise and to morphological deformation of features across stacks. We applied the method to image mosaicking and image alignment registration steps and evaluated its performance with 20 human subjects on CLSM images with stained blood vessels. Our experimental evaluation showed significant benefits of automation for 3D volume reconstruction in terms of achieved accuracy, consistency of results and performance time. In addition, the results indicate that the differences between registration accuracy obtained by experts and by novices disappear with the proposed semi-automatic registration technique while the absolute registration accuracy increases.

Journal Article↗
PubMed2006

Adolescent and young adult heroin patients: drug use and success in methadone maintenance treatment.

This study examined the impact of methadone maintenance treatment on an inclusive group of adolescent and young adult opiate-dependent patients, ages 15-23, admitted over a 6-year period, during their first year in the program. Retention in treatment was the primary outcome variable, and at 12 months, 48% were still in treatment. The findings were: (a) a stepwise discriminant function analysis revealed that patients who consistently used heroin were at a greater risk of leaving treatment within the first 12 months; (b) the use of cocaine was an indicator of higher levels of heroin use in those who reached the one-year mark; (c) among patients who stayed in treatment for one year, there was a significant reduction in heroin use, a trend toward a reduction in cocaine use, and no significant impact on benzodiazepine use; and (d) the group that stayed in treatment was slightly younger than the group that left before the first year ended. There were no gender or ethnic differences between the two groups. Suggestions for interventions that might improve treatment outcome are presented.

Adolescent↗
PubMed2004

Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose.

BACKGROUND: Treatment with pegylated interferon (peginterferon) and ribavirin for 48 weeks is more effective than conventional interferon and ribavirin in patients with chronic hepatitis C. OBJECTIVE: To assess the efficacy and safety of 24 or 48 weeks of treatment with peginterferon-alpha2a plus a low or standard dose of ribavirin. DESIGN: Randomized, double-blind trial. SETTING: 99 international centers. PATIENTS: 1311 patients with chronic hepatitis C. INTERVENTION: Peginterferon-alpha2a, 180 microg/wk, for 24 or 48 weeks plus a low-dose (800 mg/d) or standard weight-based dose (1000 or 1200 mg/d) of ribavirin. MEASUREMENT: Sustained virologic response: undetectable HCV RNA concentration at the end of treatment and during 12 to 24 weeks of follow-up. RESULTS: Overall and in patients infected with HCV genotype 1, 48 weeks of treatment was statistically superior to 24 weeks and standard-dose ribavirin was statistically superior to low-dose ribavirin. In patients with HCV genotype 1, absolute differences in sustained virologic response rates between 48 and 24 weeks of treatment were 11.2% (95% CI, 3.6% to 18.9%) and 11.9% (CI, 4.7% to 18.9%), respectively, between standard- and low-dose ribavirin. Sustained virologic response rates for peginterferon-alpha2a and standard-dose ribavirin for 48 weeks were 63% (CI, 59% to 68%) overall and 52% (CI, 46% to 58%) in patients with HCV genotype 1. In patients with HCV genotypes 2 or 3, the sustained virologic response rates in the 4 treatment groups were not statistically significantly different. CONCLUSION: Treatment with peginterferon-alpha2a and ribavirin may be individualized by genotype. Patients with HCV genotype 1 require treatment for 48 weeks and a standard dose of ribavirin; those with HCV genotypes 2 or 3 seem to be adequately treated with a low dose of ribavirin for 24 weeks.

Adult↗
PubMed2004

Efficacy and safety of two-dose regimens of peginterferon alpha-2a compared with interferon alpha-2a in chronic hepatitis C: a multicenter, randomized controlled trial.

OBJECTIVES: This study compared the efficacy and safety of peginterferon alpha-2a 135 microg/wk, peginterferon alpha-2a 180 microg/wk and interferon alpha-2a in patients with chronic hepatitis C. METHODS: A total of 639 patients received peginterferon alpha-2a 135 microg or 180 microg once weekly, or interferon alpha-2a 3 MIU thrice weekly for 48 wk. RESULTS: Sustained virological responses were significantly higher with peginterferon alpha-2a than with interferon alpha-2a 3 MIU (28% in the 135 microg and 180 microg peginterferon alpha-2a groups vs 11% with interferon alpha-2a, p = 0.001). The proportion of patients with clinically significant histological improvement was lower in the peginterferon alpha-2a 135 microg (48%) than the 180 microg group (58%, p = 0.035 vs peginterferon alpha-2a 135 microg), but similar to that in the interferon alpha-2a group (45%, p = 0.820 vs peginterferon alpha-2a 135 microg and p = 0.017 vs peginterferon alpha-2a 180 microg, respectively). The overall safety profiles were similar for the three treatments. In patients with chronic hepatitis C, peginterferon alpha-2a 135 microg/wk and 180 microg/wk produced similar sustained virological response rates, both of which were significantly higher than that achieved with interferon alpha-2a thrice weekly. A significantly higher proportion of patients treated with the 180 microg dose of peginterferon alpha-2a had clinically significant histological improvement.

Adult↗
PubMed2003

Neural networks to identify glaucomatous visual field progression.

PURPOSE: To describe a method to determine progression of glaucoma based on visual field thresholds. DESIGN: Observational retrospective longitudinal cohort study. METHODS: A back propagation neural network with three hidden layers was developed with commercial software. Visual field data from 80 patients who participated in the Advanced Glaucoma Intervention Study (AGIS) were used. Glaucomatous visual field progression was defined as a change of 4 or more units in the AGIS score, confirmed by at least two sequential subsequent tests. Inputs to the neural network consisted of threshold measurements from 55 visual field locations from the baseline examination and each follow-up examination. The data set was randomized so the sequence of examinations would not influence the training or testing of the neural network. Two thirds of the randomized data were used for training and the remaining one third for testing. RESULTS: The mean age of 80 patients enrolled in AGIS at initial examination was 67.4 (+/- 7.3 standard deviation [SD]) years. The average follow-up period was 7.2 (+/-2.3 SD) years and the mean duration between examinations was 0.46 (+/- 0.39 SD) years. The neural network estimated the probability of progression for each baseline and follow-up comparison with an average sensitivity of 86% and specificity of 88%. The area under the receiver operating characteristic (ROC) curve was 0.92, with a sensitivity of 86% at the 80% specificity level and a sensitivity of 91% at the 90% specificity level. CONCLUSIONS: From analysis of AGIS data, progression of glaucoma could be detected from visual field thresholds with a neural network.

Aged↗
PubMed2003

Twelve weeks of follow-up is sufficient for the determination of sustained virologic response in patients treated with interferon alpha for chronic hepatitis C.

BACKGROUND/AIMS: The current standard for the determination of sustained virologic response in patients treated for hepatitis C is undetectable hepatitis C virus (HCV) RNA 24 weeks following the completion of therapy. Sensitive molecular tests may permit earlier determination of sustained virologic response following the completion of therapy in end-of-treatment responders. METHODS: We examined this possibility in 1441 patients, who received 48 weeks of treatment with either standard or pegylated interferon alpha-2a. HCV RNA was determined by polymerase chain reaction assay (Amplicor HCV Monitor vs. 2.0) at baseline and monitored at 4-week intervals throughout the treatment and 24-week post-treatment follow-up periods. RESULTS: End-of-treatment and sustained response were achieved in 624 and 342 patients, respectively. For all treatments, relapse was most frequent at weeks 52 and 56 and became rare following week 60. Only six patients out of 348 patients (2%) became HCV RNA positive between weeks 60 and 72. Analysis of baseline characteristics failed to identify a specific set of parameters associated with early relapse. CONCLUSIONS: This finding suggests that determination of HCV RNA levels at 12 weeks of follow-up may be sufficient for making decisions related to the management of most patients treated with standard or pegylated interferon alpha.

Adult↗
PubMed2003

Peginterferon alpha-2a (40kD) [Pegasys] improves HR-QOL outcomes compared with unmodified interferon alpha-2a [Roferon-A]: in patients with chronic hepatitis C.

BACKGROUND: Use of unmodified interferon alpha-2a in chronic hepatitis C is associated with impaired health-related quality of life during therapy. Treatment with peginterferon alpha-2a (40kD) provides an improved sustained response over unmodified interferon alpha-2a. OBJECTIVES: To compare health-related quality of life during treatment for patients receiving peginterferon alpha-2a (40kD) [Pegasys] versus unmodified interferon alpha-2a [Roferon]. DESIGN: A randomised, international, multicentre, open-label, parallel group study. SETTING: 36 centres worldwide. PATIENTS: Interferon-naïve patients (n = 531) with chronic hepatitis C. INTERVENTIONS: Peginterferon alpha-2a (40kD) 180 mirog once a week (n = 267) for 48 weeks or unmodified interferon alpha-2a 6 million IU three times a week for 12 weeks followed by 36 weeks of 3 million IU three times a week (n = 264). MEASUREMENTS: Fatigue Severity Scale and 36-item Short-Form Health Survey (SF-36). RESULTS: At weeks 2 and 12, differences favouring peginterferon alpha-2a (40kD) were seen on seven of eight domains and both summary scores of the SF-36 (p < 0.05 to p < 0.01). At weeks 2, 12 and 24, patients receiving peginterferon alpha-2a (40kD) had less disabling fatigue (p < 0.01) than those receiving unmodified interferon alpha-2a. CONCLUSION: Treatment with peginterferon alpha-2a (40kD) is associated with less disabling fatigue and less impairment in patient functioning and well-being during treatment than unmodified interferon alpha-2a. In addition to safety and efficacy, the impact on health-related quality of life may be an important consideration for physicians when selecting an optimal treatment regimen.

Adult↗
PubMed2002

Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection.

BACKGROUND: Treatment with peginterferon alfa-2a alone produces significantly higher sustained virologic responses than treatment with interferon alfa-2a alone in patients with chronic hepatitis C virus (HCV) infection. We compared the efficacy and safety of peginterferon alfa-2a plus ribavirin, interferon alfa-2b plus ribavirin, and peginterferon alfa-2a alone in the initial treatment of chronic hepatitis C. METHODS: A total of 1121 patients were randomly assigned to treatment and received at least one dose of study medication, consisting of 180 microg of peginterferon alfa-2a once weekly plus daily ribavirin (1000 or 1200 mg, depending on body weight), weekly peginterferon alfa-2a plus daily placebo, or 3 million units of interferon alfa-2b thrice weekly plus daily ribavirin for 48 weeks. RESULTS: A significantly higher proportion of patients who received peginterferon alfa-2a plus ribavirin had a sustained virologic response (defined as the absence of detectable HCV RNA 24 weeks after cessation of therapy) than of patients who received interferon alfa-2b plus ribavirin (56 percent vs. 44 percent, P<0.001) or peginterferon alfa-2a alone (56 percent vs. 29 percent, P<0.001). The proportions of patients with HCV genotype 1 who had sustained virologic responses were 46 percent, 36 percent, and 21 percent, respectively, for the three regimens. Among patients with HCV genotype 1 and high base-line levels of HCV RNA, the proportions of those with sustained virologic responses were 41 percent, 33 percent, and 13 percent, respectively. The overall safety profiles of the three treatment regimens were similar; the incidence of influenza-like symptoms and depression was lower in the groups receiving peginterferon alfa-2a than in the group receiving interferon alfa-2b plus ribavirin. CONCLUSIONS: In patients with chronic hepatitis C, once-weekly peginterferon alfa-2a plus ribavirin was tolerated as well as interferon alfa-2b plus ribavirin and produced significant improvements in the rate of sustained virologic response, as compared with interferon alfa-2b plus ribavirin or peginterferon alfa-2a alone.

Adult↗
PubMed2002

Protein kinase C-associated kinase (PKK) mediates Bcl10-independent NF-kappa B activation induced by phorbol ester.

Protein kinase C-associated kinase (PKK) is a recently described kinase of unknown function that was identified on the basis of its specific interaction with PKC beta. PKK contains N-terminal kinase and C-terminal ankyrin repeats domains linked to an intermediate region. Here we report that the kinase domain of PKK is highly homologous to that of two mediators of nuclear factor-kappa B (NF-kappa B) activation, RICK and RIP, but these related kinases have different C-terminal domains for binding to upstream factors. We find that expression of PKK, like RICK and RIP, induces NF-kappa B activation. Mutational analysis revealed that the kinase domain of PKK is essential for NF-kappa B activation, whereas replacement of serine residues in the putative activation loop did not affect the ability of PKK to activate NF-kappa B. A catalytic inactive PKK mutant inhibited NF-kappa B activation induced by phorbol ester and Ca(2+)-ionophore, but it did not block that mediated by tumor necrosis factor alpha, interleukin-1 beta, or Nod1. Inhibition of NF-kappa B activation by dominant negative PKK was reverted by co-expression of PKC beta I, suggesting a functional association between PKK and PKC beta I. PKK-mediated NF-kappa B activation required IKK alpha and IKK beta but not IKK gamma, the regulatory subunit of the IKK complex. Moreover, NF-kappa B activation induced by PKK was not inhibited by dominant negative Bimp1 and proceeded in the absence of Bcl10, two components of a recently described PKC signaling pathway. These results suggest that PKK is a member of the RICK/RIP family of kinases, which is involved in a PKC-activated NF-kappa B signaling pathway that is independent of Bcl10 and IKK gamma.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Prognostic factors and early predictability of sustained viral response with peginterferon alfa-2a (40KD).

BACKGROUND/AIMS: Baseline factors and early decline in serum hepatitis C virus RNA are predictive of sustained virological response to interferon therapy in patients with chronic hepatitis C. We evaluated the prognostic value of baseline factors and early viral RNA among patients treated with peginterferon alfa-2a (40KD). METHODS: Data were pooled from three randomized trials involving 814 patients treated with peginterferon alfa-2a (40KD) (90, 135, or 180 mirog). Stepwise and multiple logistic regression identified independent baseline factors associated with response. Receiver operating characteristic curves for both absolute values and log(10) decline in viral RNA at 4, 8, 12 and 24 weeks of therapy were created. RESULTS: Independent prognostic factors for sustained virological response included viral genotype non-1, low pretreatment viral load, age (<40 years), no cirrhosis and body weight (<85 kg). In addition, alanine aminotransferase quotient (>3) and histological activity index score (>10) were also independently prognostic. Receiver operating characteristic curves showed that detectable or less than 2-log(10) decline in viral RNA at week 12 predicted sustained virological non-response (negative predictive value is 98%) . CONCLUSIONS: In patients with chronic hepatitis C treated with peginterferon alfa-2a (40KD), the decision to continue or stop treatment can be made as early as week 12.

Adult↗
PubMed2002

Hepatitis C virus and human immunodeficiency virus-1 co-infection in former heroin addicts in methadone maintenance treatment.

OBJECTIVES: To investigate hepatitis C (HCV) and human immunodeficiency virus (HIV-1) prevalence in former opiate or heroin addicts currently in methadone maintenance treatment (MMT). METHODS: Retrospective chart review for patients (n = 342) currently attending two MMT clinics affiliated with New York Presbyterian Hospital (Adolescent Development Program, ADP: n = 106, median age 30 years; Adult Clinic, AC: n = 236, median age 45 years), as of May 2000. RESULTS: Overall seroprevalence of those tested was 67% for HCV (ADP, 44%; AC, 80%), and 29% for HIV-1 (ADP, 13%, AC, 39%). Co-infection was present in 26% of patients (ADP, 13%; AC, 35%). Prevalence of HCV reached 92% in the 45-49 year old group (n = 53). The greatest HIV-1 prevalence (45%) was in the 35-39 year old group (n = 33). There was a linear relationship between infection seroprevalence and age at admission into MMT. CONCLUSIONS: The high prevalence of HCV and HIV-1 infections in MMT patients varies both by current age and by age at admission to MMT. This population needs risk reduction education and treatment for HCV and HIV- 1.

Adult↗
PubMedDate not supplied

The itching, burning eye: diagnostic algorithm and management options.

The healthy ocular surface is a complex, composite unit that is essential for patient comfort and visual function. A number of components need to work in an integrated manner to ensure that this is achieved, and a variety of causes can result in the final common symptom complex that can be termed the itching, burning eye. Many of these causes may be due to relatively common and simple issues related to lid disease, allergies, tear dysfunction, excessive computer use, exposure to polluted environment, and convergence problems. However, a smaller group may have potentially more serious pathology due to causes such as underlying immune dysfunction, or tumors; rarely, intraocular conditions and some neurological causes may present with ocular redness and grittiness. Failure or delay in the diagnosis of these latter entities can result in significant morbidity to the eye. This article will clarify issues related to the functioning of the ocular surface, provide a diagnostic algorithm for managing these patients, and discuss the current knowledge in the management of these conditions once they are diagnosed. It is targeted at the practicing ophthalmologist and should help him or her to manage this problem effectively.

Algorithms↗