Information is presented from 555 patients with Dukes B and C rectal cancers treated by curative resection who were entered into the National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol R-01 between November 1977 and October 1986. Their average time on study was 64.1 months. The patients were randomized to receive no further treatment (184 patients), postoperative adjuvant chemotherapy with 5-fluorouracil, semustine, and vincristine (MOF) (187 patients), or postoperative radiation therapy (184 patients). The chemotherapy group, when compared with the group treated by surgery alone, demonstrated an overall improvement in disease-free survival (P = .006) and in survival (P = .05). Employing the proportional hazards model, a global test was used to determine the presence of treatment interactions. Investigation of stratification variables employed in this study indicated that sex, and to a lesser extent age and Dukes stage, made individual contributions to the disease-free survival and the survival benefit from chemotherapy. When evaluated according to sex, the benefit for chemotherapy at 5 years, both in disease-free survival (29% vs. 47%; P less than .001; relative odds, 2.00) and in survival (37% vs. 60%; P = .001; relative odds, 1.93), was restricted to males. When males were tested for age trend with the use of a logistic regression analysis, chemotherapy was found to be more advantageous in younger patients. When the group receiving post-operative radiation (4,600-4,700 rad in 26-27 fractions; 5,100-5,300 rad maximum at the perineum) was compared to the group treated only by surgery, there was an overall reduction in local-regional recurrence from 25% to 16% (P = .06). No significant benefit in overall disease-free survival (P = .4) or survival (P = .7) from the use of radiation has been demonstrated. The global test for interaction to identify heterogeneity of response to radiation within subsets of patients was not significant. In conclusion, this investigation has demonstrated a benefit from adjuvant chemotherapy (MOF) for the management of rectal cancer. The observed advantage was restricted to males. Postoperative radiation therapy reduced the incidence of local-regional recurrence, but it failed to affect overall disease-free survival and survival.
This review considers recent developments in our understanding of the properties of TRAb, particularly measurement of the antibodies and their sites of action and synthesis. Two new assay methods have allowed considerable improvements in the sensitivity, specificity, precision, and ease of measuring TRAb. In particular: 1) receptor assays based on inhibition of receptor-purified labeled TSH binding to detergent-solubilized TSH receptors and 2) bioassays based on stimulation of cAMP release from monolayer cultures of isolated thyroid cells. Detailed studies with the two assays indicate that TSH receptor antibodies nearly always act as TSH agonists in patients with a history of Graves' hyperthyroidism. Studies in areas of dietary iodine sufficiency suggest that measurement of the antibodies at various stages in the course of treating Graves' disease can be of value in predicting the outcome of therapy. However, in areas of iodine deficiency, difficulties in the ability of patients' thyroid tissue to recover from the effects of antithyroid drugs may prevent the receptor antibodies from causing a relapse of thyrotoxicosis. Consequently, the predictive value of receptor antibody measurements would be expected to be lower in these geographical areas. Although patients with a history of Graves' hyperthyroidism nearly always have TRAb which act as TSH agonists, about 20% of patients with frank hypothyroidism due to autoimmune destruction of the thyroid have TRAb which act as TSH antagonists (blocking antibodies). There is some evidence that these blocking antibodies can cause hypothyroidism particularly in the neonate. With regard to the site of synthesis of TRAb, there is now direct evidence that they are synthesized by thyroid lymphocytes, particularly the lymphocytes in close proximity to thyroid follicular cells. This is consistent with the well established effects of antithyroid treatment (drugs, radioiodine, or surgery) on TRAb levels in addition to their effects on thyroid hormone synthesis. Recent studies using affinity labeling with 125I-labeled TSH have enabled elucidation of the structure of the TSH receptor. TSH receptors in human, porcine, and guinea pig thyroid tissue have a two-chain structure in which the TSH binding site is formed on the outside surface of the cell membrane by a water-soluble A subunit (Mr approximately 50 K). The A subunit is linked by a disulfide bridge and weak noncovalent bonds to the amphiphilic B subunit (Mr approximately 30 K). This subunit, which penetrates the lipid bilayer, probably forms the site for interaction of the receptor with the regulatory subunits of adenylate cyclase.
A dividend-ratio model is introduced here that makes the log of the dividend-price ratio on a stock linear in optimally forecast future one-period real discount rates and future one-period growth rates of real dividends. If ex post discount rates are observable, this model can be tested by using vector autoregressive methods. Four versions of the linearized model, differing in the measure of discount rates, are tested for U.S. time series 1871-1986 and 1926-1986: a version that imposes constant real discount rates, and versions that measure discount rates from real interest rate data, aggregate real consumption data, and return variance data. The results yield a metric to judge the relative importance of real dividend growth, measured real discount rates, and unexplained factors in determining the dividend-price ratio.
In this article we test the random walk hypothesis for weekly stock market returns by comparing variance estimators derived from data sampled at different frequencies. The random walk model is strongly rejected for the entire sample period (1962-1985) and for all subperiods for a variety of aggregate returns indexes and size-sorted portfolios. Although the rejections are due largely to the behavior of small stocks, they cannot be attributed completely to the effects of infrequent trading or time-varying volatilities. Moreover, the rejection of the random walk for weekly returns does not support a mean-reverting model of asset prices.
The role of estradiol in the regulation of its cognate receptor in MCF-7 cells was investigated in this study. After treatment with 10(-9) M estradiol, the level of receptor protein was measured using an enzymeimmunoassay. By 6 h, the receptor protein declined by about 60% from a level of approximately 3.6 to 1.2 fmol/micrograms DNA. The level of receptor remained suppressed for 24-48 h. Similar results were obtained with an estrogen receptor (ER) binding assay. The steady state level of ER mRNA was determined by an RNase protection assay. Estrogen treatment resulted in a maximum suppression of mRNA by 6 h. Receptor mRNA remained depressed for 48 h. Transcription run on experiments demonstrated a transient decrease of about 90% in ER transcription after 1 h. By 3-6 h transcription increased approximately 2-fold and remained elevated for at least 48 h. These data suggest that estrogen down-regulates ER mRNA by inhibition of ER gene transcription at early times and by a posttranscriptional effect on receptor mRNA at later times.
This article develops a theory in which concentrated-trading patterns arise endogenously as a result of the strategic behavior of liquidity traders and informed traders. Our results provide a partial explanation for some of the recent empirical findings concerning the patterns of volume and price variability in intraday transaction data.