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A New Approach to Measurement of Mutagenesis in Mammalian Cells
cancer and the QFIA was positive in 50 (sensitivity of 76%). By comparison, the SPC on the same BW were positive in only 30 (46%). In the patients with primary cancer in Table 1, ANFI had a sensitivity of 66% to 85%; SPC had a sensitivity of 14% to 55%. There were 9 patients who had pulmonary metastases from other malignancies (lymphoma, 2; adenocarcinoma! unknown primary, 3; melanoma, 2; endometrial cancer, 1; squamous cell head/neck primary 1);QFIA on BW identified 6 of these 9 patients. The 40 patients who were identified as having nonmalignant disease (defined as no histologic evidence for malignancy) could be divided into 2 groups. The first group of 30 patients (- ANFII- FI Cy/- PAP) had a variety of pulmonary diseases. These patients have been followed up for 10 to 18 months with no evidence of malignancy. In the second group of 10 patients (+ ANFII ± FI Cy/- Pap), 2 had culture-proven tuberculosis, 8 had long smoking histories, and 2 have increasing masses on chest film, but there is no definite histologic evidence of malignancy. This may reflect the high sensitivity of QFIA and the
low sensitivity of nonthoracotomy techniques in the early diagnosis of lung cancer: All patients are being followed up to assess the true diagnostic specificity of QFlA. These data suggest that QFIA would be an excellent addition to the diagnostic techniques used to identify patients with pulmonary malignancy. REFERENCES 1 Fontana RS, Sanderson DR, Taylor WF, et ale Early lung cancer detection: Mayo Clinic study. Am Rev Resp Dis 1984; 130:561-65 2 Flehinger 8J, Melamed MR, Zaman M8, et ale Early lung cancer detection: Memorial Sloan-Kettering study. Am Rev Resp Dis
1984; 130:555-60
3 Frost JK, Ball WC, Levin ML, et ale Early lung cancer detection: Johns Hopkins study. Am Rev Resp Dis 1984; 130:549-54 4 Hemstreet G~ West SS, Weems WL, et ale Quantitative ftuorescence measurements of AO-stained normal and malignant bladder cells. Int J Cancer 1983; 31:577 5 Golden JF, West SS, Shingleton HM, et aleA screening system for cervical cancer cytology. J Histol Chern Cytol Chem 1979; 27: 522-28
Session 2 A New Approach to Measurement of Mutagenesis In Mammalian cells* Charles Waldren, Ph.D.; Carol jones, Ph.D.; and Theodore T; Puck, Ph.D.
This new approach makes possible separate evaluation of localized mutations, small deletions, large deletions and nondisjunctional events. It promises effective decrease in human mutation frequency, which may significantly lower incidence of somatic and germ cell genetic disease. Current studies include attempts to simplify the procedure and further to increase its sensitivity by increasing target size of the genetic markers, as by use of 2D gels in the detection of changes in protein biosynthesis and DNA structures.
and genetic diseases both are initiated by mutation in a single cell. We previously demonstrated that conventional methods for measurement of mutagenesis in mammalian cells are seriously in error. This is so because measurements are carried out at high doses of mutagens where most of the cells suffer lethal mutations. When the curves so obtained are extrapolated back to the low levels representing common human exposures, the killed cells fail to register their contributions so that the amount of mutagenesis is underestimated. This situation has been remedied by (a) using human CHO hybrid cells in which the scored genetic markers are located on a human chromosome that is unnecessary for cell reproduction, so that marker mutations and lethal events are dissociated; (b) using cell surface antigens as quantitative genetic markers; and (c) using the increased sensitivity so obtained to confine measurements to low doses of mutagens that produce minimal cell killing and that more closely approximate conditions of common human exposure. Data have been obtained for x-ray doses as low as 25 rads, which indicate that conventional measurements of mutagenesis underestimate the actual values in the low dose region by more than 200-fold. The kinds of lesions that are especially missed by conventional measurements are the larger chromosomal insults like deletions and nondisjunctional events that are particularly important in cancer and human genetic diseases.
he objective of this study was to develop a practical and reliable model of localized bronchogenic carcinoma in laboratory rodents in order to investigate the neoplastic process. This was done by impregnating cotton threads with the potent chemical carcinogen, benzo(a)pyrene (BP). These BP-impregnated threads were then coated with a silicone rubber sheath to control the release ofBP from the threads. The prepared threads were sewn around four cartilage rings in the ventral tracheal wall of guinea pigs and hamsters. The animals were sacrificed periodically, and the tracheal epithelium adjacent to the thread was assessed, in a single-blind fashion, by two histopathologists. The first study consisted of94 Camm-Hartley guinea pigs: 48 experimental animals with BP-impregnated threads and 46 control animals with nonimpregnated threads. The sec-
*Eleanor Roosevelt Institute for Cancer Research, Denver. Aided by grants from the Markey Fund, the Reynolds Industries, and National Institutes of Health No POI UD 02080. Reprint requem: Dr. Puck, 1899 Gaylord, Denver 80206
*From the University of British Columbia, Pulmonary Research Laboratory, Vancouver, B.C., Canada. Supported by the B.C. Lung Association.
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4S
A Practical Model of Bronchogenic carcinoma In camm-Harley Guinea Pigs and Golden Syrian Hamsters* t: C. Bainbridge, M.D.;] C. Hogg, M.D.;] L. Wright, M.D.; and D. C. Wal1ce~ Ph.D.
T
29th Aspen Lung Conference
low sensitivity of nonthoracotomy techniques in the early diagnosis of lung cancer: All patients are being followed up to assess the true diagnostic specificity of QFlA. These data suggest that QFIA would be an excellent addition to the diagnostic techniques used to identify patients with pulmonary malignancy. REFERENCES 1 Fontana RS, Sanderson DR, Taylor WF, et ale Early lung cancer detection: Mayo Clinic study. Am Rev Resp Dis 1984; 130:561-65 2 Flehinger 8J, Melamed MR, Zaman M8, et ale Early lung cancer detection: Memorial Sloan-Kettering study. Am Rev Resp Dis
1984; 130:555-60
3 Frost JK, Ball WC, Levin ML, et ale Early lung cancer detection: Johns Hopkins study. Am Rev Resp Dis 1984; 130:549-54 4 Hemstreet G~ West SS, Weems WL, et ale Quantitative ftuorescence measurements of AO-stained normal and malignant bladder cells. Int J Cancer 1983; 31:577 5 Golden JF, West SS, Shingleton HM, et aleA screening system for cervical cancer cytology. J Histol Chern Cytol Chem 1979; 27: 522-28
Session 2 A New Approach to Measurement of Mutagenesis In Mammalian cells* Charles Waldren, Ph.D.; Carol jones, Ph.D.; and Theodore T; Puck, Ph.D.
This new approach makes possible separate evaluation of localized mutations, small deletions, large deletions and nondisjunctional events. It promises effective decrease in human mutation frequency, which may significantly lower incidence of somatic and germ cell genetic disease. Current studies include attempts to simplify the procedure and further to increase its sensitivity by increasing target size of the genetic markers, as by use of 2D gels in the detection of changes in protein biosynthesis and DNA structures.
and genetic diseases both are initiated by mutation in a single cell. We previously demonstrated that conventional methods for measurement of mutagenesis in mammalian cells are seriously in error. This is so because measurements are carried out at high doses of mutagens where most of the cells suffer lethal mutations. When the curves so obtained are extrapolated back to the low levels representing common human exposures, the killed cells fail to register their contributions so that the amount of mutagenesis is underestimated. This situation has been remedied by (a) using human CHO hybrid cells in which the scored genetic markers are located on a human chromosome that is unnecessary for cell reproduction, so that marker mutations and lethal events are dissociated; (b) using cell surface antigens as quantitative genetic markers; and (c) using the increased sensitivity so obtained to confine measurements to low doses of mutagens that produce minimal cell killing and that more closely approximate conditions of common human exposure. Data have been obtained for x-ray doses as low as 25 rads, which indicate that conventional measurements of mutagenesis underestimate the actual values in the low dose region by more than 200-fold. The kinds of lesions that are especially missed by conventional measurements are the larger chromosomal insults like deletions and nondisjunctional events that are particularly important in cancer and human genetic diseases.
he objective of this study was to develop a practical and reliable model of localized bronchogenic carcinoma in laboratory rodents in order to investigate the neoplastic process. This was done by impregnating cotton threads with the potent chemical carcinogen, benzo(a)pyrene (BP). These BP-impregnated threads were then coated with a silicone rubber sheath to control the release ofBP from the threads. The prepared threads were sewn around four cartilage rings in the ventral tracheal wall of guinea pigs and hamsters. The animals were sacrificed periodically, and the tracheal epithelium adjacent to the thread was assessed, in a single-blind fashion, by two histopathologists. The first study consisted of94 Camm-Hartley guinea pigs: 48 experimental animals with BP-impregnated threads and 46 control animals with nonimpregnated threads. The sec-
*Eleanor Roosevelt Institute for Cancer Research, Denver. Aided by grants from the Markey Fund, the Reynolds Industries, and National Institutes of Health No POI UD 02080. Reprint requem: Dr. Puck, 1899 Gaylord, Denver 80206
*From the University of British Columbia, Pulmonary Research Laboratory, Vancouver, B.C., Canada. Supported by the B.C. Lung Association.
~cer
'-.J
4S
A Practical Model of Bronchogenic carcinoma In camm-Harley Guinea Pigs and Golden Syrian Hamsters* t: C. Bainbridge, M.D.;] C. Hogg, M.D.;] L. Wright, M.D.; and D. C. Wal1ce~ Ph.D.
T
29th Aspen Lung Conference