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  • Cell & Developmental Biology  (6)
  • Corrosion casting  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Forms of lung lymphatics: A scanning electron microscopic study of casts (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 233 (1992), S. 547-554 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: In a recent study, rats given monocrotaline underwent angiogenesis on their pleural surfaces. The rats also had novel structures in their bronchovascular bundles that were detected by scanning electron microscopy of vascular casts. These vessels could have been either new blood capillaries or dilated lymphatic capillaries. To determine if these structures were lymphatics or new blood vessels, specimens from animals that were undergoing angiogenesis were compared to those that were not. Finding similar structures in normal animals would imply that they were lymphatic. The second purpose of this work was to describe the three-dimensional anatomy of the lymphatics of the lung. Cast lymphatics were found in most lungs with edema or angiogenesis, but were rare in other conditions. The vascular structures in question were found in animals not undergoing angiogenesis and were, therefore, lymphatic. Additionally, scanning electron angiogenesis and were, therefore, lymphatic. Additionally, scanning electron microscopy of casts showed several distinct forms of lymphatics in the lung. Prelymphatics are tissues planes beneath the pleura and around bronchovascular structures. They join reservoir, conduit or tubulo-saccular lymphatics. Reservoir lymphatics are broad ribbon-like structures with textured surfaces and small laterally branching pouches. They occur on the pleural surface, are closely linked with prelymphatics, and join conduit lymphatics. Conduit lymphatics are tubular structures that may contain valves, twist and go great distances without accepting tributaries. On the pleural surface, they may wind around blood vessels and vary greatly in diamater. Sacculo-tubular lymphatics surround arteries, veins and bronchioles. They have thin walls with wide saccular segments. They may be so dense that they form cylinders around the vessels or airways. Different forms of lung lymphatics suggest different function and potential. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092330409
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  • 2
    Digitale Medien
    Digitale Medien
    Surrogate endpoint biomarkers for cervical cancer chemoprevention trials (1995)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 59 (1995), S. 113-124 
    Details
    ISSN: 0730-2312
    Schlagwort(e): Aneuploidy ; cervical intraepithelial neoplasia (CIN) ; cytophotometry dysplasia ; HPV morphometry ; oncogenes ; tumor markers ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Cervical intraepithelia neoplasia (CIN) represents a spectrum of epithelial changes that provide an excellent model for developing chemopreventive interventions for cervical cancer. Possible drug effect surrogate endpoint biomarkers are dependent on the agent under investigation. Published and preliminary clinical reports suggest retinoids and carotenoids are effective chemopreventive agents for CIN. Determination of plasma and tissue pharmacology of these agents and their metabolites could serve as drug effect intermediate endpoints. In addition, retinoic acid receptors could serve as both drug and biological effect intermediate endpoints. Possible biological effect surrogate endpoint biomarkers include cytomorphological parameters, proliferation markers, genomic markers, regulatory markers, and differentiation. Given the demonstrated causality of human papillomavirus (HPV) for cervical cancer, establishing the relationship to HPV will be an essential component of any biological intermediate endpoint biomarker. The pathologic effect surrogate endpoint biomarker for cervical cancer is CIN, used clinically for years. The desired effect for chemopreventive trials is complete regression or prevention of progression. In planning chemopreventive trials, investigators need to consider spontaneous regression rates, the subjective nature of detecting CIN, and the impact of biopsy on regression.If intermediate endpoint biomarkers that met the above criteria were available for cervical cancer, then new chemopreventive agents could be rapidly explored. The efficacy of these new agents could be determined with a moderate number of subjects exposed to minimal risk over an acceptable amount of time. The impacts on health care for women would be significant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jcb.240590915
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  • 3
    Digitale Medien
    Digitale Medien
    Three-dimensional structure of the bronchial microcirculation in sheep (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 243 (1995), S. 357-366 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Bronchial circulation ; Corrosion casting ; Pulmonary artery ; Pulmonary circulation ; Microscopy ; scanning ; electron ; Sheep ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Background: The bronchial circulation affects both pulmonary vascular and airway activity. Fundamental to understanding the role of the bronchial microcirculation in health and disease is understanding its anatomy. This study sought to identify specific structural elements that might contribute to the drop that occurs between the systemic blood pressure of the bronchial artery and the low pressure of the pulmonary bed into which the bronchial circulation flows and to better describe the connections of the bronchial and pulmonary circulations. METHODS: To do this, the lungs of five sheep were cast by injecting a resin through bronchial and pulmonary arteries. After taking samples for light microscopy, the tissue was digested and the casts were viewed with a scanning electron microscope. RESULTS: Casts of extrapulmonary bronchial arteries were structurally similar to other systemic arteries. Tortuous ones spiraled around bronchi and large blood vessels. Intrapulmonary bronchial arteries, about 100-300 μm in diameter, had sharp branching and deep focal constrictions with great rugosity that completely shut off the flow of the resin. These vessels correspond to the Sperrarterien described by von Hayek (and could cause the resistance associated with the pressure drop). Vasa vasorum ran in the walls of intrapulmonary pulmonary arteries for a variable distance before they entered the lumens of the pulmonary arteries. The smallest blood vessel found that was supplied with vasa vasorum was a bronchial artery 42 μm in diameter. Capillary-like networks with large luminal diameters were found on the pleural surface. CONCLUSIONS: Scanning electron microscopy of microvasular casts provides a fresh description of the bronchial circulation, further delineates the communications of these two circulations, and may structurally account for some pressure drop between the bronchial and pulmonary circulations. © 1995 Wiley-Liss, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092430310
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  • 4
    Digitale Medien
    Digitale Medien
    Selection criteria for breast cancer chemoprevention subjects (1993)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 234-241 
    Details
    ISSN: 0730-2312
    Schlagwort(e): Breast cancer risk ; chemoprevention ; intermediate biomarkers ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Early phase chemoprevention trials differ from standard therapeutic clinical trials because asymptomatic, healthy people are treated with a potentially toxic intervention for a prolonged period of time. Current subject selection protocols have relied upon epidemiological methods to identify highrisk individuals. Most available data provide risk estimates for various individual risk factors, but few have reported risk estimates for combinations of risk factors. Selection criteria for the large tamoxifen intervention trial (NSABP P1) were developed from the work of Gail et al. [1]. The Gail model takes into account non-genetic factors (e.g., nulliparity, age at menarche, preexisting pathological conditions) and genetic factors (family history). Using a lifetime risk of 10% of developing breast cancer as a standard to intervention trial. This approach has been criticized for being insufficiently selective (i.e., all women ≥60 yrs), but appears to be the best available method to select subjects for a chemoprevention trial. Other approaches have been based on identification of very high-risk women with acknowledged pathologic conditions [lobular carcinoma in situ, ductal carcinoma in situ (DCIS)]. Attempting to use these proliferative lesions as pathologic endpoints for drug effect has not been attempted. DCIS as a risk factor for tamoxifen intervention was excluded because of controversies over its management and because of frequent difficulties in distinguishing microinvasive from non-invasive lesions. Women treated for early stage breast cancer (Stage I) may be subjects for early stage chemopreventive interventions.We propose the use of intermediate endpoint biomarkers and genetic markers as entry criteria for early phase chemoprevention trials. For colorectal cancer chemoprevention, we have used a two-step selection process. The first step was based on epidemiologic risk assessment. Entry into the study required that a potential intermediate biomarker be positive and quantifiable. The relationship between modulation of a pre-transformational biomarker and development of cancer ultimately needs proof in a primary interventional trial; however, this methodology may permit screening of potential chemopreventive agents at lower cost and more rapid turn-around times. In early chemopreventive agent testing for breast cancer chemoprevention, we propose a similar two-step procedure. Epidemiological and/or pathological criteria for risk would be followed by a procedure to obtain cellular material. The cellular material would be assayed for pre-transformational cellular change.Identifying predictive genes in familial breast cancer cohorts such as the modified BRCA1 gene promises to select individuals at high familial and potentially physiological or environmental risk. The identification of the abnormal gene product in individuals and families will provide another important group of subjects for chemopreventive interventions. The identification of high-risk subjects for breast cancer chemoprevention, particularly those with familial genetic risk, carries important ethical problems. Such women may have difficulties obtaining health and life insurance, deciding to have children, and obtaining work. Chemoprevention trials with genetic selection criteria will need to develop methods of dealing with these issues.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jcb.240531143
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  • 5
    Digitale Medien
    Digitale Medien
    Colon cancer chemoprevention: Clinical development of aspirin as a chemopreventive agent (1997)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 67 (1997), S. 148-158 
    Details
    ISSN: 0730-2312
    Schlagwort(e): aspirin ; colon cancer chemoprevention ; cyclooxygenase isoforms (COX-1 and COX-2) ; NSAIDs ; prostaglandins (PGE2 and PGF2α) ; surrogate end-point biomarkers (SEBs) ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: We have studied aspirin as a potential chemopreventive for colorectal cancer, completing Phase I studies on aspirin pharmacology and potential biomarker assays (prostaglandins, PGE2 and PGF2α and cyclooxygenase modulation) in normal human subjects. These studies have determined the optimal dose of aspirin for future Phase IIa and IIb chemopreventive trials in high-risk cohorts of patients for colon cancer. Aspirin's effects on rectal prostaglandins are prolonged, detectable even after aspirin and its metabolite are removed from the plasma. Aspirin-mediated inhibition of prostaglandin production in the human rectal epithelium may be related to direct suppression of cyclooxygenase transcription and not to enzyme inactivation by acetylation. A systematic method to monitor adherence (self-report, telephone contact, pill count, and microelectronic monitoring) has been established for future trials. Strategies to improve recruitment of high-risk cohorts have been developed. Phase IIa non-randomized studies with aspirin at 81 mg in high-risk cohorts (resected Duke's A colon cancer, Duke's C colon cancer treated with adjuvant therapy and disease-free at 5 years, history of colon adenomas 〉 1 cm, two or more first-degree relatives with colon cancer, and familial adenomatous polyposis and hereditary non-polyposis colorectal cancer syndromes) are currently being conducted for surrogate end-point biomarker (prostaglandins, cyclooxygenase, cellular mucins, and proliferation) modulation. J. Cell. Biochem. Suppls. 28/29:148-158. Published 1998 Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Microvascular casting of the lung: Effects of various fixation protocols (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 185-191 
    Details
    ISSN: 0741-0581
    Schlagwort(e): Histologic techniques ; Scanning electron microscopy ; Blood vessels ; Pulmonary circulation ; Microcirculation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Although techniques for preparing specimens for light and electron microscopy are well established, few studies have sought to establish methods for corrosion casting of the microscopic vessels of the lung. The effects of two concentrations of glutaraldehyde, formaldehyde, and no fixative (saline control) on the filling and structure of the microvascular casts of the lung were studied. All fixatives were infused 5 minutes before casting.Formaldehyde's fixation effects were intermediate between those of glutaraldehyde and no fixation. Leakage of casting material was increased in the animals that were fixed less. Digestion time was prolonged and more undigested tissue was found in the group receiving the concentrated glutaraldehyde, although the difference in neither of these features alone reached statistical significance. Circumferential bands occurred more frequently in the large vessel casts of the less fixed animals, which may account for the less filling microvasculature in these lungs. However, good quality casts were obtained with each method.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1060080205
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