ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-0646
    Keywords: Oltipraz ; chemoprevention ; dithiolethiones ; pharmacokinetics ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Pharmacological studies on Oltipraz [4-methyl-5(pyrazinyl-2)-1-2-dithiole-3-thione)] were conducted with normal healthy subjects using various doses and schedules. Administration of single doses (1, 2 and 3 mg/kg) resulted in detectable drug levels in the serum (mean peak serum concentrations 16, 61 and 205 ng, respectively) and urine. The t1/2 was short (4.4, 4.1 and 5.3 hours respectively) and no steady state was achieved after multiple daily doses for 12 days. Introduction of a loading dose during the first day produced a steady state when 1.5 and 2.0 mg/kg/day were used. Daily administration of Oltipraz sustained the steady state with insignificant variations. Consumption of a high fat diet increased the serum and urine concentrations of Oltipraz (30–60%) compared to the low fat diet. Two subjects experienced flatulence during the administration of the drug. One subject developed numbness and pain in the thumbs with occurrence of small purplishblack spots resembling those observed in subacute endocarditis. These changes disappeared 10 days after discontinuation of the drug. No changes in peripheral blood counts, biochemical profile or thyroid function tests were observed after four weeks of Oltipraz. Further studies with a larger number of healthy subjects are needed for clarification of the safety and biological efficacy of small doses of Oltipraz during chronic administration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 1-8 
    ISSN: 0730-2312
    Keywords: chemoprevention ; clinical trials ; intermediate biomarkers ; prostate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The term “cancer chemoprevention” refers to the prevention of cancer by intervening with drugs prior to the malignant (i.e., invasive) stage of carcinogenesis. The development of chemopreventive drugs is the major objective of the Chemoprevention Branch at the National Cancer Institute.The testing of drug for cancer chemoprevention differs from testing of those for cancer treatment. Chemopreventive drug trials involve healthy target populations, and the endpoints of reduced cancer incidence or mortality, reduced/eliminated precancerous lesions, or increased latency must be achieved with little or no drug toxicity.The design of cancer chemoprevention trials for prostate presents several problems, such as the age of the study population and undependable methods for detecting microscopic foci by sequential sampling. A major motivation for organizing this workshop is the development of strategies for the design of chemopreventive intervention trials for prostate cancer.One of the most difficult problems of chemoprevention drug testing is the necessity of lengthy trials due to the long developmental period of many cancers. This is especially true for prostate cancer. A major solution to the problem is the use of intermediate biomarkers, defined as morphological or molecular intraepithelial changes that can constitute short-term endpoints in chemoprevention clinical trials. They are categorized as histological, genetic, proliferation-related, and differentiation-related. Modulation of intermediate biomarkers, instead of cancer incidence, as trial endpoints would allow chemoprevention trials to be of shorter duration, to use fewer subjects, and to be of lower cost. Review of the current status of prostatic intermediate biomarkers, and methods for identifying and validating them, are also major reason for convening this workshop. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 15-21 
    ISSN: 0730-2312
    Keywords: chemoprevention ; clinical trial ; drug development ; intermediate biomarker ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The Chemoprevention Branch of the National Cancer Institute has established a progam for the development of safe and effective cancer chemopreventive agents. This program includes identification of new agents, testing for efficacy in vitro and in animals, studies in animals to model clinical use, and preclinical toxicity and metabolism evaluation. Ultimately, the most promising agents progress to clinical trials. The long period required for cancer onset presents a significant challenge to the design of clinical trials for chemoprevention. Phase 111 trials in which cancer reduction is the endpoint require large subject group (tens of thousands) and follow-up duration of more than five years. Because of these requirements, the costs of such trials are high. The Chemoprevention Branch is addressing this challange by expansion of the preclinical and Phase II clinical efficacy efforts to include intermediate biomarkers of carcinogenesis as study endpoints.The Chemoprevention Branch's studies focus on the development of biomarkers with high reliability and predictive value for cancer. Both single markers and batteries of complementary and parallel markers are evaluated. Among the criteria for biomarkers for chemoprevention studies are the following: (1) differential expression in normal and high risk tissue, (2) appearance early in carcinogenesis (the earlier a reliable biomarker appears, the greater is the chance for successful intervention with a chemopreventive agent), (3) high sensitivity, specificity, and accuracy relative to cancer, (4) ease of measurement (use of non-invasive techniques and small tissue samples is preferable), (5) demonstration of modulation by chemopreventive agents, and (6) correlation of modulation with decreased cancer incidence. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 1-12 
    ISSN: 0730-2312
    Keywords: bladder cancer ; chemoprevention ; intermediate biomarkers ; intermediate endpoint biomarkers ; surrogate endpoints ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The term cancer chemoprevention refers to the prevention of prolongation of carcinogenesis by intervention with drugs prior to the malignant (i.e., invasive) stage. The development of chemopreventive drugs is the major objective of the Chemoprevention Branch of the National Cancer Institute. Neoplastic lesions of the urinary bladder present a unique opportunity for evaluating chemopreventive agents because of (1) the accessibility of the lesions to observation and biopsy, and (2) those patients who have been successfully treated for a primary lesion represent a population at unusually high risk for recurrence and/or progression.Although 70-80% of bladder cancers initially present as superficial, papillary transitional cell neoplasms with limited potential for invasion, the incidence of recurrence is high after resection (60-75%). Recurrent tumors are highly unpredictable, and may be of higher grade of stage (progression). Although recurrence is responsible for high treatment-related morbidity, progression represents the greatest potential for mortality. Thus, potential chemopreventive agents considered here would modulate bladder carcinogenesis from initiation of normal-appearing tissue through progression of superficial tumors.Clinical trials of chemopreventive drugs involve healthy target populations, and the endpoints are reduced cancner incidence or mortality, reduced/eliminated precancerous lesions or increased latency, with none to minimal toxicity. Since cancers may not appear for 20-30 years, two of the most difficult aspects of testing these drugs in intervention trials are the long observation poeriods and large study populations required to measure cancer incidence reduction. However, observing the regression or recurrence of superficial bladder lesions (TIS, T1, Ta) requires relatively short time periods. Thus, these lesions lend themselves to the investigation of intermediate biomarkers, defined as morphologic and/or molecular alterations in tissue between initiation and tumor invasion. It is hypothesized that modulation of one or more biomarkers would interrupt carcinogenesis and result in a decrease in cancer incidence. Thus, evaluation of biomarkers as surrogate endpoints would allow bladder trials to be of even shorter duration, use fewer subjects and be lower in cost. In addition, intermediate biomarkers could predict which superficial lesions (or normal-appearing tissue) have the greatest potential for neoplastic progression. Development of strategies for the design of intrvention trials for bladder cancer and review of the current status of intermediate biomarkers in the bladder, and methods for their validation, are major objectives of this workshop.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0730-2312
    Keywords: chemoprevention ; genetic/regulatory biomarkers ; high-risk cohorts ; intraepithelial neoplasia ; phase II clinical trials, risk biomarkers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Quantifiable, well-characterized cancer risk factors demonstrate the need for chemoprevention and define cohorts for chemopreventive intervention. For chemoprevention, the important cancer risk factors are those that can be measured quantitatively in the subject at risk. These factors, called risk biomarkers, can be used to identify cohorts for chemoprevention. Those modulated by chemopreventive agents may also be used as endpoints in chemoprevention studies. Generally, the risk biomarkers fit into categories based on those previously defined by Hulka: 1) carcinogen exposure, 2) carcinogen exposure/effect, 3) genetic predisposition, 4) intermediate biomarkers of cancer, and 5) previous cancers.Besides their use in characterizing cohorts for chemoprevention trials, some risk biomarkers can be modulated by chemopreventive agents. These biomarkers may be suitable surrogate endpoints for cancer incidence in chemoprevention intervention trials. The criteria for risk biomarkers defining cohorts and serving as endpoints are the same, except that those defining cohorts are not necessarily modulated by chemopreventive agents. A primary criterion is that the biomarkers fit expected biological mechanisms of early carcinogenesis - i.e., differential expression in normal and high-risk tissue, on or closely linked to the causal pathway for the cancer, and short latency compared with cancer. They must occur in sufficient number to allow their biological and statistical evaluation. Further, the biomarkers should be assayed reliably and quantitatively, measured easily, and correlated to cancer incidence. Particularly important for cancer risk screening in normal subjects is the ability to use noninvasive techniques that are highly specific, sensitive, and quantitative.Since carcinogenesis is a multipath process, single biomarkers are difficult to correlate to cancer, as they may appear on only one or a few of the many possible causal pathways. As shown in colorectal carcinogenesis, the risks associated with the presence of biomarkers may be additive or synergistic. That is, the accumulation of genetic lesions is the more important determinant of colorectal cancer compared with the presence of any single lesion. Thus, batteries of biomarker abnormalities, particularly those representing the range of carcinogenesis pathways, may prove more useful than single biomarkers both in characterizing cohorts at risk and defining modulatable risks.Risk biomarkers are already being integrated into many chemoprevention intervention trials. One example is the phase II trial of oltipraz inhibition of carcinogen-DNA adducts in a Chinese population exposed to aflatoxin B1. Also, urine samples from subjects in this trial will be screened for the effect of oltipraz on urinary mutagens. A second example is a chemoprevention protocol developed for patients at high risk for breast cancer; the cohort is defined both by hereditary risk and the presence of biomarker abnormalities. Modulation of the biomarker abnormalities is a proposed endpoint. Also, dysplastic lesions, such as prostatic intraepithelial neoplasia, oral leukoplakia and colorectal adenomas, have been used to define high-risk cohorts and as potential modulatable surrogate endpoints in chemoprevention trials. J. Cell. Biochem. 25S:1-14. © 1997 Wiley-Liss, Inc. This article is a U.S. Government work and, as such, is in the public domain in the United States of America.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0730-2312
    Keywords: cancer chemopreventive agents ; drug development ; retinoids ; DFMO ; NSAIDs ; oltipraz ; Phase I clinical trials ; Phase II clinical trials ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Clinical chemoprevention trials of more than 30 agents and agent combinations are now in progress or being planned. The most advanced agents are well known and are in large Phase III chemoprevention intervention trials or epidemiological studies. These drugs include several retinoids [e.g., retinol, retinyl palmitate, all-trans-retinoic acid, and 13-cis-retinoic acid], calcium, βcarotene, vitamin E, tamoxifen, and finasteride. Other newer agents are currently being evaluated in or being considered for Phase II and early Phase III chemoprevention trials. Prominent in this group are all-trans-N-(4-hydroxy phenyl)retinamide (4-HPR) (alone and in combination with tamoxifen), 2-difluoromethylornithine (DFMO), nonsteroidal antiinflammatory drugs (aspirin, piroxicam, sulindac), oltipraz, and dehydroepiandrostenedione (DHEA).A third group is new agents showing chemopreventive activity in animal models, epidemiological studies, or in pilot clinical intervention studies. They are now in preclinical toxicology testing or Phase I safety and pharmacokinetics trials preparatory to chemoprevention efficacy trials. These agents include S-allyl-l-cysteine, curcumin, DHEA analog 8354 (fluasterone), genistein, ibuprofen, indole-3-carbinol, perillyl alcohol, phenethyl isothiocyanate, 9-cis-retinoic acid, sulindac sulfone, tea extracts, ursodiol, vitamin D analogs, and p-xylyl selenocyanate. A new generation of agents and agent combinations will soon enter clinical chemoprevention studies based primarily on promising chemopreventive activity in animal models and in mechanistic studies. Among these agents are more efficacious analogs of known chemopreventive drugs including novel carotenoids (e.g., α-carotene and lutein). Also included are safer analogs which retain the chemopreventive efficacy of the parent drug such as vitamin D3 analogs. Other agents of high interest are aromatase inhibitors (e.g., (+)-vorozole), and protease inhibitors (e.g., Bowman-Birk soybean trypsin inhibitor). Combinations are also being considered, such as vitamin E with l-selenomethionine. Analysis of signal transduction pathways is beginning to yield classes of potentially active and selective chemopreventive drugs. Examples are ras isoprenylation and epidermal growth factor receptor inhibitors. 1997 Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0730-2312
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: This is the second publication of Clinical Development Plans from the National Cancer Institute, Division of Cancer Prevention and Control, Chemoprevention Branch and Agent Development Committee. The Clinical Development Plans summarize the status of promising chemopreventive agents regarding evidence for safety and chemopreventive efficacy in preclinical and clinical studies. They also contain the strategy for further development of these drugs, addressing pharmacodynamics, drug effect measurements, intermediate biomarkers for monitoring efficacy, toxicity, supply and formulation, regulatory approval, and proposed clinical trials. Sixteen new Clinical Development Plans are presented here: curcumin, dehydroepiandrosterone, folic acid, genistein, indole-3-carbinol, perillyl alcohol, phenethyl isothiocyanate, 9-cis-retinoic acid, 13-cis-retinoic acid, l-selenomethionine and 1,4-phenylenebis(methylene)selenocyanate, sulindac sulfone, tea, ursodiol, vitamin A, and (+)-vorozole. The objective of publishing these plans is to stimulate interest and thinking among the scientific community on the prospects for developing these and future generations of chemopreventive drugs. © 1997 Wiley-Liss, Inc.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 1975-11-01
    Print ISSN: 0021-9584
    Electronic ISSN: 1938-1328
    Topics: Chemistry and Pharmacology , Education
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 1992-11-01
    Print ISSN: 0167-6997
    Electronic ISSN: 1573-0646
    Topics: Chemistry and Pharmacology , Medicine
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 1992-01-01
    Print ISSN: 0730-2312
    Electronic ISSN: 1097-4644
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...