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Morgan TR, Ghany MG, Kim HY, Snow KK, Shiffman ML, De Santo JL, Lee WM, Di Bisceglie AM, Bonkovsky HL, Dienstag JL, Morishima C, Lindsay KL, Lok AS. Outcome of sustained virological responders with histologically advanced chronic hepatitis C. Hepatology 2010; 52:833-44. [PMID: 20564351 PMCID: PMC2932862 DOI: 10.1002/hep.23744] [Citation(s) in RCA: 362] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UNLABELLED Retrospective studies suggest that subjects with chronic hepatitis C and advanced fibrosis who achieve a sustained virological response (SVR) have a lower risk of hepatic decompensation and hepatocellular carcinoma (HCC). In this prospective analysis, we compared the rate of death from any cause or liver transplantation, and of liver-related morbidity and mortality, after antiviral therapy among patients who achieved SVR, virologic nonresponders (NR), and those with initial viral clearance but subsequent breakthrough or relapse (BT/R) in the HALT-C (Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis) Trial. Laboratory and/or clinical outcome data were available for 140 of the 180 patients who achieved SVR. Patients with nonresponse (NR; n = 309) or who experienced breakthrough or relapse (BT/R; n = 77) were evaluated every 3 months for 3.5 years and then every 6 months thereafter. Outcomes included death, liver-related death, liver transplantation, decompensated liver disease, and HCC. Median follow-up for the SVR, BT/R, and NR groups of patients was 86, 85, and 79 months, respectively. At 7.5 years, the adjusted cumulative rate of death/liver transplantation and of liver-related morbidity/mortality in the SVR group (2.2% and 2.7%, respectively) was significantly lower than that of the NR group (21.3% and 27.2%, P < 0.001 for both) but not the BT/R group (4.4% and 8.7%). The adjusted hazard ratio (HR) for time to death/liver transplantation (HR = 0.17, 95% confidence interval [CI] = 0.06-0.46) or development of liver-related morbidity/mortality (HR = 0.15, 95% CI = 0.06-0.38) or HCC (HR = 0.19, 95% CI = 0.04-0.80) was significant for SVR compared to NR. Laboratory tests related to liver disease severity improved following SVR. CONCLUSION Patients with advanced chronic hepatitis C who achieved SVR had a marked reduction in death/liver transplantation, and in liver-related morbidity/mortality, although they remain at risk for HCC.
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research-article |
15 |
362 |
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Di Bisceglie AM, Shiffman ML, Everson GT, Lindsay KL, Everhart JE, Wright EC, Lee WM, Lok AS, Bonkovsky HL, Morgan TR, Ghany MG, Morishima C, Snow KK, Dienstag JL. Prolonged therapy of advanced chronic hepatitis C with low-dose peginterferon. N Engl J Med 2008; 359:2429-41. [PMID: 19052125 PMCID: PMC2606037 DOI: 10.1056/nejmoa0707615] [Citation(s) in RCA: 334] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND In patients with chronic hepatitis C who do not have a response to antiviral treatment, the disease may progress to cirrhosis, liver failure, hepatocellular carcinoma, and death. Whether long-term antiviral therapy can prevent progressive liver disease in such patients remains uncertain. METHODS We conducted a randomized, controlled trial of peginterferon alfa-2a at a dosage of 90 microg per week for 3.5 years, as compared with no treatment, in 1050 patients with chronic hepatitis C and advanced fibrosis who had not had a response to previous therapy with peginterferon and ribavirin. The patients, who were stratified according to stage of fibrosis (622 with noncirrhotic fibrosis and 428 with cirrhosis), were seen at 3-month intervals and underwent liver biopsy at 1.5 and 3.5 years after randomization. The primary end point was progression of liver disease, as indicated by death, hepatocellular carcinoma, hepatic decompensation, or, for those with bridging fibrosis at baseline, an increase in the Ishak fibrosis score of 2 or more points. RESULTS We randomly assigned the patients to receive peginterferon (517 patients) or no therapy (533 patients) for 3.5 years. The level of serum aminotransferases, the level of serum hepatitis C virus RNA, and histologic necroinflammatory scores all decreased significantly (P<0.001) with treatment, but there was no significant difference between the groups in the rate of any primary outcome (34.1% in the treatment group and 33.8% in the control group; hazard ratio, 1.01; 95% confidence interval, 0.81 to 1.27; P=0.90). The percentage of patients with at least one serious adverse event was 38.6% in the treatment group and 31.8% in the control group (P=0.07). CONCLUSIONS Long-term therapy with peginterferon did not reduce the rate of disease progression in patients with chronic hepatitis C and advanced fibrosis, with or without cirrhosis, who had not had a response to initial treatment with peginterferon and ribavirin. (ClinicalTrials.gov number, NCT00006164.)
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Multicenter Study |
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334 |
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Eichler EE, Holden JJ, Popovich BW, Reiss AL, Snow K, Thibodeau SN, Richards CS, Ward PA, Nelson DL. Length of uninterrupted CGG repeats determines instability in the FMR1 gene. Nat Genet 1994; 8:88-94. [PMID: 7987398 DOI: 10.1038/ng0994-88] [Citation(s) in RCA: 313] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Analysis of 84 human X chromosomes for the presence of interrupting AGG trinucleotides within the CGG repeat tract of the FMR1 gene revealed that most alleles possess two interspersed AGGs and that the longest tract of uninterrupted CGG repeats is usually found at the 3' end. Variation in the length of the repeat appears polar. Alleles containing between 34 and 55 repeats, with documented unstable transmissions, were shown to have lost one or both AGG interruptions. These comparisons define an instability threshold of 34-38 uninterrupted CGG repeats. Analysis of premutation alleles in Fragile X syndrome carriers reveals that 70% of these alleles contain a single AGG interruption. These data suggest that the loss of an AGG is an important mutational event in the generation of unstable alleles predisposed to the Fragile X syndrome.
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31 |
313 |
4
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Snow KK, Seddon JM. Do age-related macular degeneration and cardiovascular disease share common antecedents? Ophthalmic Epidemiol 1999; 6:125-43. [PMID: 10420212 DOI: 10.1076/opep.6.2.125.1558] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss and blindness in elderly Americans. The etiology of this condition remains unknown and treatment options are limited. Some epidemiological findings point to a cardiovascular risk profile among persons with AMD. Documented risk factors for cardiovascular disease (such as age, smoking, hypertension, hypercholesterolemia, post-menopausal estrogen use, diabetes, and dietary intake of fats, alcohol and antioxidants) have also been associated with AMD in some studies. This raises the possibility that the causal pathways for cardiovascular disease and AMD may share similar risk factors. Future research on this hypothesis could lead to important insights into etiologic factors for AMD. Research could also identify modifiable risk factors and suggest new treatment options which could prevent AMD, slow its progression, or reduce visual loss. Susceptible individuals could then be targeted for improved health promotion and disease prevention measures for this disabling and highly prevalent disorder.
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Review |
26 |
167 |
5
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Hagerman RJ, Hull CE, Safanda JF, Carpenter I, Staley LW, O'Connor RA, Seydel C, Mazzocco MM, Snow K, Thibodeau SN. High functioning fragile X males: demonstration of an unmethylated fully expanded FMR-1 mutation associated with protein expression. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 51:298-308. [PMID: 7942991 DOI: 10.1002/ajmg.1320510404] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Fragile X (fra(X)) males with a standardized IQ score of 70 or higher represent a high functioning (HF) or nonretarded fra(X) male group. This group, which does not include nonpenetrant males, has received little research attention to date. Of 221 fra(X) males who had been evaluated through The Children's Hospital in Denver since 1981 and had completed cognitive or developmental testing, 29 (13%) were high functioning by the above definition. We found that HF males on the whole had a lower cytogenetic score and were younger than retarded fra(X) males, but there was no difference between these two groups in the number of typical fra(X) physical manifestations present. FMR-1 DNA testing was performed on 134 fra(X) males and methylation status was determined for 51 of these. A greater percentage of HF males had a mosaic pattern or an incompletely methylated full mutation than did retarded males. A unique DNA pattern, an unmethylated fully expanded mutation, was discovered in 3 of the highest functioning fra(X) males. Protein studies performed on 2 of these males demonstrated the presence of FMR-1 protein, albeit at lower levels than normal. FMR-1 protein was not present in retarded fra(X) males. Significant FMR-1 protein expression may be responsible for higher cognitive functioning in the 2 males with unmethylated fully expanded mutations compared to retarded fra(X) males.
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31 |
163 |
6
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Abstract
PURPOSE To review from a historical perspective the recent epidemic of Acanthamoeba keratitis and its association with the use of contact lenses and to provide a summary of recent techniques that have allowed earlier diagnosis and treatment. METHODS The authors reviewed available literature on Acanthamoeba keratitis from 1973 to the present, with emphasis on the history of the epidemic and its association with contact lenses, identification of risk factors, preventive measures, and current diagnostic techniques. We also estimated the annual incidence of Acanthamoeba keratitis during 1985 through 1987 from available data. RESULTS Before the popularization of soft-contact-lens wear, Acanthamoeba keratitis was extremely rare; however, an epidemic began in the early 1980s, and the number of cases increased dramatically beginning in 1984. By 1985, the association of this infection with the use of contact lenses was firmly established, and in 1987, the infection was shown to occur more commonly among men, as well as in contact-lens wearers who failed to disinfect their lenses as frequently as recommended, swam while wearing lenses, or used homemade instead of commercially prepared saline solution. Adoption of "disposable" contact lenses in the late 1980s did not decrease the risk of Acanthamoeba keratitis, and concerns remain regarding the effectiveness of some contact-lens disinfectants; however, recent advances in diagnosis and treatment have improved the prognosis. The annual incidence during 1985 through 1987 was conservatively estimated at 1.65 to 2.01 cases per million contact-lens wearers. It is unclear whether the incidence is declining. CONCLUSION Acanthamoeba keratitis has now been recognized worldwide, and there are clear associations of this infection with improper contact-lens hygiene, particularly contact with water. Recent methods allow earlier diagnosis and thus improved outcomes. The epidemic provides a valuable lesson on how a new technology can be associated with unforeseen complications and exemplifies how rapid dissemination of epidemiologic information can aid in controlling an emergent epidemic.
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Historical Article |
27 |
127 |
7
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Koenig JI, Snow K, Clark BD, Toni R, Cannon JG, Shaw AR, Dinarello CA, Reichlin S, Lee SL, Lechan RM. Intrinsic pituitary interleukin-1 beta is induced by bacterial lipopolysaccharide. Endocrinology 1990; 126:3053-8. [PMID: 2190803 DOI: 10.1210/endo-126-6-3053] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using a specific antiserum recognizing recombinant rat interleukin-1 beta (IL-1 beta), immunoreactive material was localized to cytoplasmic granules in anterior pituitary endocrine cells and colocalized with TSH in thyrotropes. Authenticity was established by Northern blot hybridization using a specific rat IL-1 beta cRNA probe, revealing a 1.8-kilobase mRNA identical to that in the spleen. The marked increase in anterior pituitary IL-1 beta message after the administration of bacterial lipopolysaccharide, raises the possibility that IL-1 beta may be involved in paracrine or autocrine regulation of pituitary function during infectious challenge.
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35 |
112 |
8
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Bonkovsky HL, Snow KK, Malet PF, Back-Madruga C, Fontana RJ, Sterling RK, Kulig CC, Di Bisceglie AM, Morgan TR, Dienstag JL, Ghany MG, Gretch DR. Health-related quality of life in patients with chronic hepatitis C and advanced fibrosis. J Hepatol 2007; 46:420-31. [PMID: 17196293 PMCID: PMC1995129 DOI: 10.1016/j.jhep.2006.10.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 10/02/2006] [Accepted: 10/20/2006] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Although the antiviral and histological benefits of peginterferon/ribavirin therapy are well established, the effects on health-related quality of life (HRQOL) and sexual health are less certain. This study assessed HRQOL and sexual health in patients with advanced fibrosis or cirrhosis in the HALT-C Trial. METHODS Subjects completed SF-36 and sexual health questionnaires prior to and after 24 weeks of peginterferon/ribavirin therapy (n=1144). Three hundred and seventy-three (33%) subjects were HCV RNA negative at week 20 and continued therapy through week 48; 258 were seen at week 72. One hundred and eighty achieved sustained virological responses (SVR) and 78 relapsed. RESULTS At baseline, patients had poorer scores for all eight SF-36 domains compared to healthy controls. Patients with cirrhosis had lower HRQOL scores than those with bridging fibrosis, as did patients with higher depression scores. SVR patients had significant improvements in seven domains, whereas relapsers had significant worsening in one domain. Sexual scores improved in SVR patients and decreased in relapsers (p=0.03). In multivariate analyses, improvements in HRQOL and sexual scores were significantly associated with SVR but were less striking in patients with lower depression scores. CONCLUSIONS Achievement of SVR after peginterferon/ribavirin therapy improves HRQOL and sexual health in chronic hepatitis C patients with advanced fibrosis or cirrhosis.
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research-article |
18 |
107 |
9
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Snow K, Tester DJ, Kruckeberg KE, Schaid DJ, Thibodeau SN. Sequence analysis of the fragile X trinucleotide repeat: implications for the origin of the fragile X mutation. Hum Mol Genet 1994; 3:1543-51. [PMID: 7833909 DOI: 10.1093/hmg/3.9.1543] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
This study addresses mechanism of instability of the FMR-1 (CGG)n-repeat, and investigates features which may distinguish between normal stable and fragile X unstable repeats. To achieve this, we have sequenced 178 alleles to analyze patterns of AGG interruptions within the CGG repeat, and have typed the (CA)n-repeat at DXS548 for 204 chromosomes. Overall, our data is consistent with the idea that the length of uninterrupted CGG repeats determines instability. We predict that certain sequence configurations [no AGG, and (CGG)9-11AGG(CGG) > or = 20] present in the general population, are predisposed towards replication slippage. Association between these proposed predisposing repeats and DXS548 alleles may explain the previously reported frequencies of fragile X mutations and large-size normal repeats on specific haplotype backgrounds. We propose that predisposing alleles arise in the general population by as yet undefined mechanism(s) which introduce a relatively long stretch of pure CGG repeat at the 3'-end (relative to the direction of transcription) of the FMR-1 repeat region. The 3' pure repeat may then be susceptible to further expansion by replication slippage. Slippage on these predisposing chromosomes could accumulate over many generations until a threshold size is reached, at which point the repeat is susceptible to greater instability (i.e. premutation stage). Thus, results suggest that evolution of fragile X full mutations could involve 4 definable stages: 1) ancestral events leading to the formation of predisposing alleles which have large total repeat length (e.g. between 35 to 50) but no AGG or 1 AGG; 2) gradual slippage of these predisposing alleles to small premutations (S alleles); 3) conversion from S alleles to larger premutations (Z); 4) massive expansion from a Z allele to a full mutation (L).
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31 |
105 |
10
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Sharma S, Brown GC, Brown MM, Shah GK, Snow K, Brown H, Hollands H. Converting visual acuity to utilities. CANADIAN JOURNAL OF OPHTHALMOLOGY 2000; 35:267-72. [PMID: 10959467 DOI: 10.1016/s0008-4182(00)80077-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Utility theory can be used to quantify dysfunction associated with various diseases and thus can represent a "hard" measure of quality of life. By determining utility values, one can compare the quality of life of patients with ocular disease to that of patients with non-ophthalmic problems. We performed a study to determine whether utility values from patients with ocular disease are associated with clinical variables, including visual acuity in the better-seeing eye, and to develop a mathematical method for converting visual acuity to utility value, if there is an association between the two. METHODS Cross-sectional study. A total of 239 patients from a tertiary care retinal practice with various ocular conditions, including macular degeneration, cataract, glaucoma and diabetic retinopathy, were interviewed under standardized conditions to determine their utility values by the time trade-off technique. Visual acuity, duration of visual loss and number of concomitant conditions were also determined. Multiple linear regression was performed to determine which variables were associated with utility values. RESULTS The mean acuity in the better-seeing eye was 0.479 (near 20/40 vision). The mean utility value was 0.72. Accordingly, the average patient in our series was willing to trade 2.8 of every 10 remaining years of life to obtain perfect vision in both eyes. Utility value was significantly associated with visual acuity in the better-seeing eye (F = 69.1, p < 0.001). Other variables were not significantly associated with utility value. The association with duration of visual loss approached statistical significance (p = 0.075). Utility values (U) for patients with ocular disease can be derived from the following formula: U = (0.374)(visual acuity in better-seeing eye) + 0.514. INTERPRETATION Utility values from patients with ocular disease were strongly associated with visual acuity and could be estimated mathematically.
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Comparative Study |
25 |
79 |
11
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Mao R, Jalal SM, Snow K, Michels VV, Szabo SM, Babovic-Vuksanovic D. Characteristics of two cases with dup(15)(q11.2-q12): one of maternal and one of paternal origin. Genet Med 2000; 2:131-5. [PMID: 11397326 DOI: 10.1097/00125817-200003000-00003] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The phenotype correlations for interstitial duplications that include the Prader-Willi/Angelman syndrome critical region are not well established. We describe two such duplication cases, one of which was of maternal origin and the other was paternal. METHODS High resolution G-banding, fluorescence in situ hybridization (FISH) for SNRP-N and D15S10 were used for cytogenetic analysis. Southern blot analyses based on parent of origin specific DNA methylation at D15S63 (PW71) locus were utilized for detection of methylated and unmethylated fragments. RESULTS The duplication was established by the FISH analysis. The molecular pattern suggested a maternal origin of the duplication in patient 1 and a paternal origin in patient 2. Patient 1 (2 years old) had developmental and speech delays with pervasive developmental disorder or mild autism, strabismus, and normal growth parameters with seizures. Patient 2 (16 years old) had global developmental delay, verbal IQ of 94, depression, obesity, food-seeking behavior, and significant behavioral problems that included self-injurious tendencies. Neither patient had significant dysmorphic features or abnormalities of internal organs. CONCLUSION The two cases suggest that some patients with 15q11.2q12 duplication may have significant anomalies, and there appear to be phenotypic differences between maternal and paternal transmission of the duplication.
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Review |
25 |
64 |
12
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Snow KK, Cote J, Yang W, Davis NJ, Seddon JM. Association between reproductive and hormonal factors and age-related maculopathy in postmenopausal women. Am J Ophthalmol 2002; 134:842-8. [PMID: 12470752 DOI: 10.1016/s0002-9394(02)01755-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The relationships between reproductive risk factors, including use of hormone replacement therapy and oral contraceptives and severity of age-related maculopathy (ARM) among postmenopausal women were evaluated. We hypothesized that exposure to endogenous or exogenous estrogens would be associated with a reduced risk of advanced ARM. DESIGN Cross-sectional study. METHODS The 394 subjects were postmenopausal women with ARM. Logistic regression analysis was used to compare the effects of several reproductive factors across two groups: 193 subjects with nonadvanced ARM and 201 subjects with advanced ARM. RESULTS Women with ARM who had used postmenopausal estrogen therapy in the past had significantly lower odds of advanced ARM than nonusers, after controlling for other known and potential risk factors (odds ratio [OR] = 0.5, 95% confidence interval [CI] = 0.30 to 0.98). Older age at menarche was associated with increased odds of advanced ARM (OR = 1.16, 95% CI = 1.00 to 1.35). CONCLUSIONS These findings suggest that exposure to exogenous estrogens may have a beneficial effect of reducing the risk of advanced types of ARM in postmenopausal women with ARM. Few therapeutic or preventive measures currently exist for ARM; therefore, these results deserve further evaluation.
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Comparative Study |
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56 |
13
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Finlay GJ, Baguley BC, Snow K, Judd W. Multiple patterns of resistance of human leukemia cell sublines to amsacrine analogues. J Natl Cancer Inst 1990; 82:662-7. [PMID: 2157028 DOI: 10.1093/jnci/82.8.662] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The antileukemia drug amsacrine and seven analogues were tested for in vitro activity against five multidrug-resistant human leukemia cell sublines (two derived from each of two Jurkat parent lines and one from the K562 line) and the corresponding parent lines (Jurkat, K562, and P388 leukemia). Resistant cell lines were derived by exposure to either amsacrine or doxorubicin. The resistance factor was calculated as the ratio of the mean IC50 value for the resistant cell line to that for the parent line. IC50 was defined as the concentration of drug inhibiting cell growth to 50% of that in control (drug-free) cultures. Patterns of cross-resistance were visualized by plotting the deviations of resistance factors from the mean resistance factor, on a logarithmic scale. Considerable variations in resistance factors were noted for each cell subline as the amsacrine substituents were altered. Four main patterns were evident: a transport-related multidrug-resistance pattern (three sublines), a pattern similar to that for a murine P388 leukemia subline resistant to amsacrine, and two patterns not observed previously. Since some of the sublines tested showed evidence of altered topoisomerase II activity, it appears that changes in the resistance pattern in these lines may reflect changes in the stability of the ternary complexes formed by the drug, the altered enzyme, and the DNA. The resistance factor was reduced from more than 100-fold to about 13-fold in three of the sublines tested and from eightfold to twofold in two others. This finding suggests that appropriate drug design may overcome several forms of multidrug resistance in human leukemia and other types of cancer.
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56 |
14
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Fernandez M, McClain ME, Martinez RA, Snow K, Lipe H, Ravits J, Bird TD, La Spada AR. Late-onset SCA2: 33 CAG repeats are sufficient to cause disease. Neurology 2000; 55:569-72. [PMID: 10953195 DOI: 10.1212/wnl.55.4.569] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
SCA-2 is an autosomal dominant inherited disorder characterized by ataxia, slow saccades, and hyporeflexia. The authors evaluated a patient with a mild balance problem with a SCA-2 allele sized at 33 CAG repeats. The authors then ascertained her 91 year-old mother, who showed disease onset at age 86 with an SCA-2 allele of identical size. Their study indicates that 33 CAG repeats can be pathogenic at the SCA-2 locus, though such an allele may produce an extremely late onset and gradual rate of disease progression.
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Case Reports |
25 |
54 |
15
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Di Bisceglie AM, Stoddard AM, Dienstag JL, Shiffman ML, Seeff LB, Bonkovsky HL, Morishima C, Wright EC, Snow KK, Lee WM, Fontana RJ, Morgan TR, Ghany MG. Excess mortality in patients with advanced chronic hepatitis C treated with long-term peginterferon. Hepatology 2011; 53:1100-8. [PMID: 21480316 PMCID: PMC3073857 DOI: 10.1002/hep.24169] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Chronic hepatitis C virus infection can cause chronic liver disease, cirrhosis and liver cancer. The Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) Trial was a prospective, randomized controlled study of long-term, low-dose peginterferon therapy in patients with advanced chronic hepatitis C who failed to respond to a previous course of optimal antiviral therapy. The aim of this follow-up analysis is to describe the frequency and causes of death among this cohort of patients. Deaths occurring during and after the HALT-C Trial were reviewed by a committee of investigators to determine the cause of death and to categorize each death as liver- or nonliver-related and as related or not to complications of peginterferon. Rates of liver transplantation were also assessed. Over a median of 5.7 years, 122 deaths occurred among 1,050 randomized patients (12%), of which 76 were considered liver-related (62%) and 46 nonliver-related (38%); 74 patients (7%) underwent liver transplantation. At 7 years the cumulative mortality rate was higher in the treatment compared to the control group (20% versus 15%, P = 0.049); the primary difference in mortality was in patients in the fibrosis compared to the cirrhosis stratum (14% versus 7%, P = 0.01); comparable differences were observed when liver transplantation was included. Excess mortality, emerging after 3 years of treatment, was related largely to nonliver-related death; liver-related mortality was similar in the treatment and control groups. No specific cause of death accounted for the excess mortality and only one death was suspected to be a direct complication of peginterferon. CONCLUSION Long-term maintenance peginterferon in patients with advanced chronic hepatitis C is associated with an excess overall mortality, which was primarily due to nonliver-related causes among patients with bridging fibrosis.
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research-article |
14 |
47 |
16
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Snow K, Ball GD. Characterization of human sperm antigens and antisperm antibodies in infertile patients. Fertil Steril 1992; 58:1011-9. [PMID: 1426351 DOI: 10.1016/s0015-0282(16)55452-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To identify which sperm antigens may elicit the production of functionally important antisperm antibodies. DESIGN Immunoblot analysis was performed on 69 serum and 9 seminal plasma samples from infertile patients, using detergent extracts of pooled donor sperm as the antigen source. Serum and seminal plasma had been previously tested by an indirect immunobead binding test (IBT); 61 IBT-positive and 17 IBT-negative samples were included in the study. Proteins recognized by IBT-positive but not IBT-negative samples were most likely to be cell surface antigens, whereas proteins recognized by both IBT-positive and IBT-negative samples were probably intracellular. Antibodies directed toward surface antigens would be most likely to affect fertilization. Characterization of sperm surface proteins on both acrosome-intact and -reacted sperm used labeling of cell surface proteins with an N-hydroxysuccinimide ester of biotin, fractionation of sperm heads and tails, and lectin binding to determine glycosylation. RESULTS Specific immunoreactivity (with respect to IBT results) was observed to 35K, 40 to 45K, 57K, 66K, and 88 to 90K MW proteins. Characterization studies identified an 88K MW glycosylated plasma membrane protein, a 66K MW inner acrosomal membrane protein, a 34K MW inner acrosomal membrane protein, and a 35K MW prominent tail protein. CONCLUSION Immunological infertility may involve several antigens characterized in this study. Further studies are necessary to determine if antibodies to these specific proteins interfere with sperm function.
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33 |
44 |
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Babovic-Vuksanovic D, Snow K, Ten RM. Mannose-binding lectin (MBL) deficiency. Variant alleles in a midwestern population of the United States. Ann Allergy Asthma Immunol 1999; 82:134-8, 141; quiz 142-3. [PMID: 10071515 DOI: 10.1016/s1081-1206(10)62586-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To describe a method for the genotype analysis of mutations in the gene encoding mannose binding lectin (MBL), study the incidence of MBL gene mutations in a population of the Midwest of the United States, and compare it with previous reports in other populations. The objective of this report is also an extensive review of the literature to analyze the importance of MBL deficiency in human disease. DATA SOURCES Blood samples were obtained from the blood bank of the Mayo Clinic. They represented a population of blood donors living in the Midwest of the United States. A review of the literature was performed by selection of articles from Medline database. STUDY SELECTION Blood samples, 148, were randomly selected from a pool of blood donors. They included both females and males. Blood donors had been previously screened by a questionnaire and were found to be generally healthy. For the literature review, articles containing original data on MBL in humans were selected. RESULTS Forty-five (30.4%) of the analyzed blood donors carried one variant allele, while 8 donors (5.4%) showed homozygosity or compound heterozygosity for MBL gene mutations. Allele frequency for the different MBL variants is provided. Our results are similar to those reported for the Danish population. Literature review provides evidence for a significant role of MBL deficiency in the innate immunity. The incidence of MBL mutations is higher among patients with recurrent infections and autoimmune disorders. CONCLUSIONS Mannose binding lectin deficiency has a definite role in the pathogenesis of primary immunodeficiency in humans and screening patients with recurrent infections and autoimmunity might be beneficial. The significance of MBL deficiency among apparently healthy blood donors remains to be determined.
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Peters W, Keystone E, Snow K, Rubin L, Smith D. Is there a relationship between autoantibodies and silicone-gel implants? Ann Plast Surg 1994; 32:1-5; discussion 5-7. [PMID: 8141526 DOI: 10.1097/00000637-199401000-00001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The present study was conducted to determine if 200 patients with silicone-gel implants demonstrated elevated levels of autoantibodies, compared with a similar group of 100 age-matched control subjects without breast implants. These results were then compared with 29 patients who had demonstrated implant rupture. Differences in the frequency of autoantibody levels were determined by the chi-squared test. Differences in autoantibody titers were determined by Wilcoxon's signed rank test. Differences were considered significant with p > 0.05. The prevalence of a positive antinuclear antibody (ANA) test (dilution 1:100) in the 200 patients with breast implants was 26.5% compared with 28% in the 100 control subjects. In 29 patients with implant rupture, only 17.2% tested ANA positive. These values were not significantly different. In addition, there were no significant differences between the ANA titers of positive patients in each group. In each of the three groups, all patients who tested ANA positive were analyzed to assess the frequency and titer of other autoantibodies, including anti-DNA, anti-cardiolipin, anti-SSA, anti-SSB, anti-SM, anti-RNP, and anti-Scl-70. There were no significant differences between the frequency or titer of any of these autoantibody levels in each of the three groups of patients. These studies strengthen the concept that there is no conclusive evidence that silicone-gel implants are related to the development of connective tissue disease.
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Fontana RJ, Bieliauskas LA, Lindsay KL, Back-Madruga C, Wright EC, Snow KK, Lok ASF, Kronfol Z, Padmanabhan L. Cognitive function does not worsen during pegylated interferon and ribavirin retreatment of chronic hepatitis C. Hepatology 2007; 45:1154-63. [PMID: 17465000 DOI: 10.1002/hep.21633] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED Treatment of chronic hepatitis C with pegylated interferon (peginterferon) and ribavirin can cause or exacerbate depression but its effects on cognitive function are largely unknown. The aim of this study was to determine whether treatment with peginterferon and ribavirin adversely impacts cognitive function in patients with chronic hepatitis C. Prior nonresponders to interferon were retreated with peginterferon alfa-2a and ribavirin for 24 (n=177) or 48 weeks (n=57) in the Hepatitis C Antiviral Long-term Treatment Against Cirrhosis trial. Cognitive function was prospectively assessed using a battery of 10 standardized neuropsychological tests at weeks 0, 24, 48, and 72. Cognitive impairment was defined based upon a global deficit score. The Beck Depression Inventory and Brief Symptom Inventory were used to assess mood status. The 57 subjects who completed 48 weeks of antiviral therapy reported significant increases in difficulty concentrating, emotional distress, and symptoms of depression, all of which improved after cessation of therapy [P<0.0001, analysis of variance (ANOVA)]. Nonetheless, the frequency of cognitive impairment did not increase during the first 24 weeks of treatment in 177 patients (34% versus 32%, P=0.64) nor in the 57 patients completing 48 weeks of treatment (P=0.48, ANOVA). CONCLUSION Retreatment of prior non-responders with peginterferon and ribavirin was not associated with objective evidence of cognitive impairment as measured by a comprehensive battery of neuropsychological tests. The lack of cognitive impairment is reassuring and suggests that self-reported symptoms of cognitive dysfunction are more likely related to the systemic and psychiatric side effects of antiviral treatment rather than measurable changes in cognition.
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Snow K, Hesseling AC, Naidoo P, Graham SM, Denholm J, du Preez K. Tuberculosis in adolescents and young adults: epidemiology and treatment outcomes in the Western Cape. Int J Tuberc Lung Dis 2018; 21:651-657. [PMID: 28482959 DOI: 10.5588/ijtld.16.0866] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING Western Cape Province, South Africa. OBJECTIVES To characterise tuberculosis (TB) epidemiology, disease presentation and treatment outcomes among adolescents (age 10-19 years) and young adults (age 20-24 years) in the Western Cape. DESIGN A retrospective, cross-sectional review of routine patient-level data from the Electronic TB Register (ETR.Net) for 2013. Site of TB disease, human immunodeficiency virus (HIV) status and TB treatment outcomes were analysed by 5-year age groups (<5, 5-9, 10-14, 15-19, 20-24 and 25 years of age). TB notification rates were calculated using census data. RESULTS Adolescents and young adults comprised 18.0% of all new TB notifications in 2013. The notification rate was 141 TB cases/100 000 person-years (py) among 10-14 year olds, 418/100 000 py among 15-19 year olds and 627/100 000 py among 20-24 year olds. HIV prevalence among TB patients was 10.9% in 10-14 year olds, 8.8% in 15-19 year olds and 27.2% in 20-24 year olds. Older adolescents (age 15-19 years) and young adults (age 20-24 years) with HIV co-infection had poor treatment outcomes: 15.6% discontinued treatment prematurely and 4.0% died. CONCLUSIONS Young people in the Western Cape suffer a substantial burden of TB, and those with TB-HIV co-infection are at high risk of treatment discontinuation.
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Wu G, Wu W, Hegde M, Fawkner M, Chong B, Love D, Su LK, Lynch P, Snow K, Richards CS. Detection of sequence variations in the adenomatous polyposis coli (APC) gene using denaturing high-performance liquid chromatography. GENETIC TESTING 2002; 5:281-90. [PMID: 11960572 DOI: 10.1089/109065701753617408] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have evaluated the usefulness of denaturing high performance liquid chromatography (dHPLC) for scanning the adenomatous polyposis coli (APC) gene for point mutations, small deletions, and insertions. Our assay consists of 28 sets of primers to amplify the 15 exons of the APC gene. All PCR reactions were amplified simultaneously using the same reaction conditions in a 96-well format and then analyzed by dHPLC, using empirically determined optimum temperatures for partial fragment denaturation. Previously studied DNA specimens from 47 familial adenomatous polyposis (FAP) patients were analyzed by dHPLC and all mutations were correctly identified and confirmed by sequence analysis. This approach identified a single-base substitution in exon 6 and a 2-bp insertion in exon 15 that initially had not been detected by single-strand conformational polymorphism (SSCP) analysis. A novel mutation in exon 15 of the APC gene, 2065delG (codon 689) that had previously been undetected by the protein truncation test (PTT) was also identified by dHPLC. We present our validation studies of dHPLC technology for APC gene analysis in terms of sensitivity and specificity and compare it to current standard scanning technologies including PTT, SSCP, and conformational sensitive gel electrophoresis (CSGE).
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June GA, Sherrod PS, Hammack TS, Amaguaña RM, Andrews WH, Arling V, Ayers S, Ayotte E, Cirigliano M, Clifford DC, Cook D, Coles C, Dabney A, Davis T, Diaz B, Driggs RM, Eliasberg S, Fain A, Fung DYC, Hammers A, Hu E, Jirele K, Keating KJ, Kogan S, Kone K, Kuyyakamont B, Luebbert K, McDonagh S, McNally S, Mettler D, Milas J, Miller C, Nelson T, Nguyen P, Pfundheller R, Phebus RK, Redding R, Richardson S, Richter E, Robinson J, Romer J, Roo DW, Smoot L, Snow K, Tate C, Tompkins L, Vanderbilt K, Varney GW, Wagner D, Wang J, Wchienroj K. Relative Effectiveness of Selenite Cystine Broth, Tetrathionate Broth, and Rappaport-Vassiliadis Medium for Recovery of Salmonella spp. from Raw Flesh, Highly Contaminated Foods, and Poultry Feed: Collaborative Study. J AOAC Int 2020. [DOI: 10.1093/jaoac/79.6.1307] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
A collaborative study was performed in 18 laboratories to validate use of Rappaport-Vassiliadis (RV) medium in the standard culture method for recovery of Salmonella spp. from raw, highly contaminated foods and poultry feed. RV medium made from its individual ingredients and incubated at 42�C was compared with selenite cystine (SC) broth incubated at 35�C and tetrathionate (TT) broth incubated at 35� and 43�C for effectiveness in recovery of Salmonella spp. Four artificially contaminated foods (oysters, frog legs, mushrooms, and shrimp) and poultry feed and one naturally contaminated food (chicken) were analyzed. The artificially contaminated foods were inoculated with single serovars of Salmonella at target levels of 0.04 colony-forming units (CFU)/g for the low level and 0.4 CFU/g for the high level. For analysis of 1125 test portions, RV medium (42�C) recovered Salmonellairom 409 test portions; TT (43�C), from 368 test portions; TT (35�C), from 310 test portions; and SC (35�C), from 334 test portions. Overall, RV medium was comparable with or better than other selective enrichments for recovery of Salmonella from the foods in this study, except mushrooms. From mushrooms, SC broth (35�C) recovered more positive test portions than did RV medium (42�C) and TT broth (43�C). The method for detection of Salmonella in raw, highly contaminated foods and
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Snow K, Jiang NS, Kao PC, Scheithauer BW. Biochemical evaluation of adrenal dysfunction: the laboratory perspective. Mayo Clin Proc 1992; 67:1055-65. [PMID: 1331628 DOI: 10.1016/s0025-6196(12)61120-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this study, we reviewed the diagnostic efficiency of laboratory tests that are performed for assessment of patients with Cushing's syndrome or adrenal insufficiency. Baseline laboratory data from patients subsequently diagnosed with adrenal dysfunction were analyzed for tests performed between 1987 and 1989 at our institution. Results were analyzed for 36 patients diagnosed with pituitary-dependent Cushing's syndrome, 15 with ectopic Cushing's syndrome, 12 with adrenal-dependent Cushing's syndrome, 20 with primary adrenal insufficiency, and 7 with secondary adrenal insufficiency. Tests reviewed were plasma cortisol, plasma corticotropin, urinary free cortisol, urinary 17-ketosteroids, urinary ketogenic steroids, low-dose and high-dose dexamethasone suppression, and metyrapone stimulation. Our findings suggest that a substantial proportion of diagnoses could be based on the results of three tests--plasma corticotropin, plasma cortisol, and urinary free cortisol. We present a nomogram that combines the results of plasma corticotropin and plasma cortisol testing to enhance the diagnostic efficiency of these tests.
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Bieliauskas LA, Back-Madruga C, Lindsay KL, Snow KK, Kronfol Z, Lok AS, Padmanabhan L, Fontana RJ. Clinical Relevance of Cognitive Scores in Hepatitis C Patients with Advanced Fibrosis. J Clin Exp Neuropsychol 2007; 28:1346-61. [PMID: 17050262 DOI: 10.1080/13803390500473720] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mild neuropsychological impairment has previously been reported in chronic hepatitis C (CHC) patients. The aim of this study was to assess the presence and severity of cognitive impairment among a cohort of CHC patients with advanced fibrosis using clinician ratings compared to classification based upon statistical methods. In addition, we set out to determine the relationship between cognitive scores and functional status. Two experienced neuropsychologists provided "clinician ratings" on a battery of 10 neuropsychological tests performed in 100 randomly selected patients participating in the HALT-C clinical trial. The overall kappa between the 2 graders on level of impairment was 0.59. Clinician ratings (the gold standard) were similarly sensitive to identifying cognitive impairment as was classification based on standard scores (44% vs. 40%). Global Deficit Scores (GDS), derived from pooling standard scores, also identified 44% of patients as having mild impairment and were highly correlated with clinician ratings (r = .81 p = < 0.0001). Neither clinician ratings nor deficit scores correlated with SF-36 subscale or summary scores but did correlate with depression scores (p < .0007). In summary, clinician ratings and deficit scores identified a similar prevalence of cognitive impairment amongst CHC patients with advanced fibrosis. There was a significant correlation between cognitive impairment and self-reported depression.
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