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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 22 (1985), S. 209-219 
    ISSN: 1432-1432
    Keywords: Collagen ; Ancestral genetic domain ; Simple sequence amplification ; Consensus sequence ; Introns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Although the major types of vertebrate collagen have a number of structural properties in common, significant DNA sequence homologies have not been detected between different portions of the helical coding domains within the same gene or between different genes. However, under non-stringent hybridization conditions we found considerable cross-homology within and between α1(I) and α2(I) chick cDNAs in the coding regions for helical sequences. Detailed analyses at the DNA sequence level have led us to propose that the gene for chick pro α2(I) collagen arose from a 9-bp primordial sequence. A consensus sequence for the 9-bp repeat was derived: GGTCCTCCT, which codes for a Gly-Pro-Pro triplet. The primordial ancestor of this 9-bp unit, GGTCCTXCT, apparently underwent duplication and divergence. Each resulting 9-bp sequence was triplicated to form a 27-bp domain, and a condensation event produced a 54-bp domain. This genetic unit then underwent multiple rounds of amplification to form the ancestral gene for the full-length helical section of α2(I). A different 9-bp consensus sequence (GGTCCCCCC) seems to have been the basis of the chick pro α1(I) gene.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of dermatology 31 (1992), S. 0 
    ISSN: 1365-4632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To be approved for marketing, a potential generic pharmaceutical product must demonstrate bioequivalence, that is, a rate and extent of absorption similar to those of the currently marketed (“innovator”) product. For oral products, design and statistical analysis for studies conducted to determine whether two products are bioequivalent have become reasonably standardized; the design is crossover, and analysis is based on the two one-sided tests principle. The purpose of this overview is to consider whether the practices for oral products apply to topical products, and where different procedures may be required. The principles behind the practices for oral products are seen, largely, to carry over to topical products.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Localized absence of epithelial Langerhans cells (LC) has been shown to affect systemic immune responses, allow microbial colonization and play a possible role in carcinogenesis. Because use of smokeless tobacco is associated with abnormal oral mucosal changes and development of carcinoma, we examined lesion and control specimens from 17 current users of smokeless tobacco to determine whether lesions showed changes in LC number or antigen expression. We identified LC by immunohistochemistry with antibodies to the antigens T6, HLA-DR, HLA-DQ, and HLA-DP. Lesion specimens contained fewer LC (means of 6 LC/mm and 10 LC/mm2) than did the corresponding control specimens (means of 14 LC/mm and 30 LC/mm2), and in each pair of lesion and autologous control specimens the reduction in LC was on average 58% (range, 3% to 95%). There were no apparent differences between lesion and control specimens in the number of LC expressing each of the four marker antigens. Reductions in LC occurred in all types of smokeless tobacco-associated lesions, regardless of increased epithelial thickness or changes in keratinization. Our data indicate that smokeless tobacco reduces the number of Langerhans cells at its site of contact with the oral mucosa.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1468-2869
    Keywords: Acquired immunodeficienty syndrome ; Substance abuse ; Hospitalization ; Ambulatory care
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective To identify features of ambulatory care associated with reduced hospitalization among drug users with acquired immunodeficiency syndrome (AIDS). Methods A nonconcurrent prospective study of hospital use by 1,369 drug users with AIDS was conducted using data from New York State Medicaid research data files linked to telephone interview data from directors of ambulatory care clinics serving this group. Results Follow-up averaged 29 months, during which 88% of subjects were hospitalized at least once. On average, those hospitalized spent 14% of follow-up time as inpatients. Hospitalization was less likely for patients in clinics with case managers (adjusted odds ratio=0.42, 95% confidence interval 0.25, 0.68) or high director’s rating of coordination of care (adjusted odds ratio=0.50, 95% confidence interval 0.29, 0.89). Multivariate analysis showed significantly less time in hospital for patients in clinics with methadone maintenance, case managers, high continuity ratings, and clinic physicians attending for hospitalized clinic patients. Conclusions Drug users with AIDS rely heavily on inpatient care, but those followed in clinics featuring greater coordination and offering special services, including methadone treatment and case management, appear to have significantly less hospital use.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-904X
    Keywords: absorption rate ; bioequivalence ; Cmax/AUClqc ; Cmax/ AUC ; exposure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The goals were to evaluate the usefulness of Cmax/AUClqc, ratio of the maximum plasma drug concentration to the area under the plasma concentration-time curve to the time of the last quantifiable concentration, in bioequivalence testing and to explore the use of exposure as a replacement for the concepts of rate and extent of drug absorption. Methods. The bioequivalence of products differing in both rate (ka) and extent (F) of absorption was assessed under conditions similar to those encountered in a typical trial. A one-compartment model drug with first-order absorption (rate constant = ka) and elimination was used. Variability was introduced in all model parameters using Monte Carlo techniques. The results were expressed in terms of the probability of declaring bioequivalence in a cross-over trial with 24 subjects using Cmax/AUClqc, AUClqc, and Cmax as bioequivalence measures. Results. The outcome of a bioequivalence trial was shown to depend on the measure. Cmax/AUClqc reflected changes in ka, but not in F. AUClqc showed dependence on F, but virtually no dependence on ka. For Cmax, a 3- to 4-fold increase in ka and a concomittant 20% decrease in F, as well as corresponding changes in the opposite directions, resulted in bioequivalent outcomes. Conclusions. It was concluded that use of Cmax/AUClqc should be discouraged and that defining bioequivalence in terms of rate and extent of absorption has major problems. The goal of bioequivalence trials should be to assure that the shape of the concentration-time curve of the test product is sufficiently similar to that of the reference product. To this end, the use of “exposure” rather than “rate and extent of absorption” concepts is encouraged.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 14 (1997), S. 967-968 
    ISSN: 1573-904X
    Keywords: secondary metrics ; Cmax ; Cmax/AUC ; bioequivalence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-904X
    Keywords: multiple-dose clinical pharmacology trials ; steady state pharmacokinetics ; aggregate evaluation ; individual evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-904X
    Keywords: pharmacokinetics ; bioequivalence ; extent of absorption ; power analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of the area under the concentration–time curve (AUC) is the method most commonly used by regulatory agencies to assess extent of drug absorption after single-dose administration of oral products. Using simulations, several approaches toward measuring the actual area, in whole or part, were tested. In addition, the performance of the peak concentration (C max), usually taken as a measure of the rate of absorption was assessed evaluating extent. Model scenarios for drugs with typical mean characteristics and statistical distributions were investigated. Using different kinetic models of disposition, the time course of the drug concentration in plasma was simulated. Intraindividual and interindividual variability and assay error were modeled using Monte Carlo techniques. The accuracy, precision, and ease of use of the various measures of extent were evaluated, and statistical power analyses were performed. Among the measures tested, the most reliable were the AUC computed up to the time of the last quantifiable concentration, without extrapolation, and C max. However, being also sensitive to rate, C max as a measure of extent is of limited potential.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The highest point of the plasma concentration-time profile, C max , is currently used by regulatory agencies to assess the rate of drug absorption after single dose administration of oral products. It is, however, quite insensitive, and a number of new measures of rate have been proposed. Using simulations, several approaches toward measuring rate were tested. A set of model scenarios for drugs with typical mean characteristics and statistical distributions was investigated. Using different kinetic models of disposition, the time course of the concentration in plasma was simulated. Intraindividual and interindividual variability and assay error were modeled using Monte Carlo techniques. The accuracy, precision, and ease of use of the various measures of rate were evaluated by simulating crossover design clinical trials and then determining the probability of declaring bioequivalence as a function of differences in rates of absorption between test and reference formulations. All of the rate measures tested showed a degree of insensitivity to changes in rate and no universally superior measure was found. Indeed, the main conclusion is that the choice of a measure should be based on simulations of the particular situation in a bioequivalence trials.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-7217
    Keywords: age ; breast fluid ; breast diseases ; breast feeding ; breast secretion ; multivariate analysis ; race ; reproductive history ; selection bias
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Studies of cytologic and biochemical constituents of nipple aspirates of breast fluid have contributed to understanding the natural history of benign and malignant breast disease. We conducted multivariate analyses using 1428 women from a recent case-control study of breast disease to determine which factors were independently associated with the ability to obtain breast fluid from nonlactating women. We then compared results from these analyses to the results from five previous studies that also used the aspiration technique of Sartorius. Four factors were consistently associated across studies with increased ability to obtain breast fluid: 1) age up to 35 to 50 years; 2) earlier age at menarche; 3) non-Asian compared to Asian ethnicity; and 4) history of lactation. Exogenous estrogen use, endogenous estrogen concentrations, phase of menstrual cycle, family history of breast cancer, type of menopause, and less than full-term pregnancy consistently did not influence ability to obtain fluid. New findings from this study shed light on some apparently contradictory findings from the previous studies. In particular, this study showed that the effects of age on ability to obtain fluid appeared to be independent of the effects of menopause. Furthermore, discrepancies in previous findings on the effects of parity on ability to obtain fluid may be explained by our finding that the increased ability to obtain fluid from parous compared to nulliparous women applied only to parous women who had breastfed.
    Type of Medium: Electronic Resource
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