1st Term Research Articles

Teaching a Select Triad in Politics & Government

I refer to the discipline of Politics and Government, rather than Political Science; because, there is no science to politics; one might as well apply Chaos Science to politics to determine the end result of some Presidential Election. Look at Truman defeating Dewey with the newspaper banner headline, “Dewey Elected”; or John F. Kennedy being assassinated; or Lyndon Johnson not running for a second term, on his own (he finished JFK’s 1st term); or, Richard M. Nixon resigning before his second term was over, after he had crushed George McGovern, winning 49 out of 50 states, in his Presidential reelection bid; or the ascent of Bill Clinton from Arkansas to oust sitting President George H. W. Bush. But, what if Newt Gingrich hadn’t rebelled? Would Bush, then, have been strong enough to overcome Clinton’s challenge? And, then, we have the beginning of a scandalous plague that would follow Bill Clinton through two terms, to include his surviving impeachment in the House, when the Senate chose not to act. But what if they had? What if Harry Byrd had taken the moral high ground and let his actions equate to his words (He said that everybody knew Bill Clinton was guilty, but the country could not stand a trial, which was a gross misrepresentation of this country’s moral fiber.) Al Gore would have become President; and, George W. Bush would have been relegated to watching baseball games in Houston, TX. Mr. Gore would have finished Bill Clinton’s second term and, in all probability, won two more terms.The entry level course for the Politics and Government Discipline is Politics, Philosophy, and Economics (PPE economics, as illustrated by national budgetary considerations and the political-economic decisions that flow from such considerations; and, finally, the politics that play out, within the framework of worldviews, and, which take shape on the canvas of national economic policy.This paper presents a select triad of courses that follow Politics, Philosophy, and Economics and which serve as foundation, building, and capstone in the teaching of Politics & Government [or Political Science, for those of you sufficiently versed in Chaos Science] to offer students a unique learning experience, as well as an enrichment opportunity for students not majoring in Politics & Government/Political Science. Collaborative learning is central to this teaching and learning model, which offers a myriad of opportunities for role play and simulation. Verbal communication skills are stressed, as is the importance of nonverbal communication. Finally, note taking, in the form of journaling, is a required element.

The experiences of teacher candidates in developing instructional multimedia materials in project based learning

Evaluation is an important component of developing educational materials so the aim of this study is to evaluate teacher candidates’ studies corresponding instructional multimedia material in project based learning according to their opinions in terms of the competencies it provides. This study was applied to a randomly selected sample of 200 students (100 females and 100 males) of various departments of Near East University and who got the course “Instructional Technologies and Materials Development” (ITMD) at the beginning of the 1st term of 2010-2011 academic year. The participants got the course “ITMD” which was carried out as a Project Based Learning. Over the period of that term, the teacher candidates learned to design and develop various multimedia instructional projects such as course software, slideshow, a web-site, etc. The teacher candidates evaluated the questionnaire which was designed according to instructional multimedia materials developed by them in PBL. At a glance result according to the analysis of the questionnaire, the teacher candidates chose “mostly” answer for preparation, organization media-use, navigation tools use, appearance design and resource use operations. Based on the findings, we will discuss practical implementations of a multimedia projects with project based learning approach in teacher candidates’ education.

유출수문곡선과 돌발홍수지수를 이용한 돌발홍수심도 산정

지금까지 돌발홍수는 주로 강우의 시공간적인 특성들을 고려한 기후학적 측면에서 관심을 가지고 연구가 진행되어 왔을 뿐 유출의 시각에서 돌발홍수를 평가하기 위한 노력은 매우 미흡하였다고 할 수 있다. 본 연구의 목적은 Bhaskar 등(2000)의 연구를 우리나라에 적용하여 유출수문곡선에 의해 돌발홍수를 설명하고, 다른 홍수사상과 돌발 홍수 사상을 구별하고자 하는데 있다. 즉, 유출수문곡선의 특성을 이용해 홍수사상에 대한 돌발홍수지수(flash flood index)를 산정함으로써 돌발홍수의 심각성 정도를 정량화하고자 하였다. 이를 위해 본 논문에서는 한강유역의 과거 101개의 홍수사상에 대해 돌발홍수의 상대심도(relative severity)를 파악하기 위하여 돌발홍수지수를 산정하였으며 또한, 2006년 7월의 집중호우에 의해 발생한 홍수사상의 돌발홍수 심도를 시공간적으로 정량화하였다. 분석 결과, 한강유역의 다른 지역에 비해 강원도 지역의 홍수 유출수문곡선들이 돌발홍수 심도를 크게 나타내었으며 중랑천 등과 같은 도시유역에서도 돌발심도가 크게 나타남을 확인 할 수 있었다. 2006년 7월 집중호우에 의한 한강유역의 돌발홍수지수를 7월 전반기, 중반기 그리고 하반기로 나누어 시공간적 공간분포를 분석한 결과, 7월 전반기의 경우 서울 주변지역의 돌발심도가 크게 나타났으며 7월 중반기의 경우 강원도 지역의 돌발홍수 심도가 크게 나타났다. The flash flood has been studied in the climatological aspect which considers temporal and spatial characteristics of rainfall. However, we have not interested in runoff hydrograph for flash flood study. Therefore, our objectives of this study are to apply a work of Bhaskar et. al (2000) which studied runoff hydrograph to represent the flash flood to Korea and also to distinguish flash flood event from general flood event. That is, we quantified the severity of flash flood by estimation of flash flood index using runoff hydrograph. This study estimated the flash flood index for investigating the relative severity of flash flood in Han river basin with 101 flood events. Also we quantified the flash flood severity for flood event by heavy rainfall occurred in July of 2006. As a result, Kangwon-do province showed more severe flash flood than other areas in Han river basin and urban area such as Jungrang cheon stream also showed severe flash flood. We analyzed a flash flood of July of 2006 by dividing July into 1st to 3rd terms. From the analysis we knew that the 1st term of July showed the severe flash flood was occurred in Seoul area and the 2nd term showed it was occurred in Kangwon-do province.

A time-averaged model for gas–solids flow in a one-dimensional vertical channel

In this study, we are interested in deriving time-smoothed governing and constitutive equations for gas–solids flow in moderately dense systems where particle–particle collision is the main energy dissipation mechanism. Results obtained from dynamic simulations of a gas–solids flow in a 1D channel are used to show that it is possible to obtain expressions for the time-averaged constitutive relations based on Taylor series expansion. We demonstrate, by comparing with time-averaged transient results, that the 1st term (or laminar) in the series expressions of most non-linear constitutive relations can yield inaccurate quantitative and qualitative results. This means that steady-state models derived by simply removing the partial time derivative from the governing equations are not suitable for gas–solids flows. This study shows that it was necessary to include many terms of the Taylor series expression of non-linear constitutive relations (such as the granular energy dissipation term) due to large-scale oscillations that were computed for all flow variables at all locations in the 1D domain. In some cases, the Taylor series expansion diverged and the Euler transformation was used to improve the convergence of these series. In this moderately dense flow system, turbulence in the gas-phase was found to be just a reaction to turbulence in the solids phase that resulted from the large-scale motion of solids clusters. This resulted in a negative turbulent gas viscosity computed due to the fact that gas (in the horizontal direction) flows only to occupy regions vacated by clusters of solids. The steady-state results obtained using the time-smoothed gas–solids flow model compared well with the time-averaged results obtained using the transient model for all flow variables.

HCMV induced IL-6 release in trophoblast and trophoblast like cells

Background Human cytomegalovirus (hCMV) infection of the trophoblasts is a crucial event in virus transmission from mother to child, being one responsible factor for intrauterine infection of the unborne. Differences of virus replication in trophoblasts depending on time point of pregnancy and degree of differentiation of trophoblasts might influence this transmission. Furthermore, immunological reactions of the trophoblasts to hCMV infection might be important defence mechanisms too. Objectives hCMV replication and interleukin-6 release in trophoblasts and trophoblast like cells (choriocarcinoma cells) was investigated. Study design Trophoblasts from term and 1st trimester placentas were isolated and infected with hCMV. hCMV production and release to the supernatant as well as interleukin-6 release and interleukin-6 mRNA production by these infected cells was measured. Choriocarcinoma cell lines (JEG-3, JAR) were treated the same. Non-infected trophoblasts were used as controls. Results In 1st trimester trophoblast, term trophoblasts and JEG-3 permissive hCMV replication was observed, although with different kinetics and efficiency. In JAR no complete virus replication was seen. High levels of interleukin-6 were measured in the supernatants of all hCMV infected cells immediately after infection. IL-6 mRNA upregulation was seen 48 h after infection in those cell types replication of hCMV occurred (1st trimester trophoblasts, term trophoblasts, JEG-3). At that time-point hCMV immediate early proteins appeared. In JARs no virus production and no IL-6 mRNA upregulation was seen, and IL-6 levels in the supernatant of these hCMV infected cells declined significantely until day 6 after infection compared to mock infected cells. Conclusion These observations show that hCMV replication is influenced by the degree of trophoblast differentiation. Interleukin-6 is upregulated by hCMV infection, but is independent of complete virus replication.

Improvement of functional outcome after radical surgery in glioblastoma patients: the efficacy of a navigation-guided fence-post procedure and neurophysiological monitoring

This retrospective study investigated the functional outcomes of patient with glioblastoma receiving radical surgery before and after the adoption of the navigation-guided fence-post (NGFP) procedure and neurophysiological monitoring. We investigated 42 glioblastoma patients receiving radical surgery in our institute between 1980 and 2005. Of the 42 patients, 18 patients from 1980 to 1996 (1st term) underwent radical surgery without navigation system guidance, NGFP, or neurophysiological monitoring; 11 patients from 1997 to 2002 (2nd term) underwent surgery with simple navigation system guidance but without NGFP procedure or neurophysiological monitoring, and 13 patients from 2003 to 2005 (3rd term) underwent surgery with the NGFP procedure and neurophysiological monitoring as appropriate. There were no significance differences between any of the three term groups in age, gender, preoperative KPS score, or 'surgical staging for glioma' according to the difficulty of surgery. The rates of 95% or greater volume reduction in each term were 38.9%, 54.5% and 76.9%. The rates of morbidity were 38.9%, 18.1% and 0%. The change in KPS scores (delta KPS) before and after the perioperative period in each term were -16.1 +/- 6.6 SEM, -9.0 +/- 5.8 SEM and +8.5 +/- 3.7 SEM, respectively. The delta KPS in the 3rd term was significantly better than those of 1st and 2nd terms (P < 0.01, Kruskal-Wallis rank test). The rate of patients who were discharged to home and who resumed daily useful life without assistance was 38.9%, 63.6% and 84.6% in each term, respectively. The mean survival times in each term were 9.9, 14.0 and 16.8 months. The introduction of the NGFP procedure and neurophysiological monitoring in glioblastoma radical surgery improved the functional outcome of patients.

Образ В.В. Путина в сознании российских граждан

The article summarizes the results of a research project which consisted in studying V.V.Putin's image that had formed in Russian citizens' consciousness, and which had been carried on for almost the whole of the 1st term of his presidency. Analysis of the data obtained has allowed a number of significant conclusions. Thus, the authors have noted a tendency indicative of citizens' demand for authoritarian type of government. The authors have shown, for that matter, that the extent of the requirement of authoritarian governance is larger in the center and among the youth than in peripheral regions and among people of elder age groups. The image of V.V.Putin was characterized by predominantly positive values assumed by all variables, which testifies to his aptness to answer the expectations of the populace and to adequately perform the role of leader. If, however, support of Putin was quite confidently expressed on the rational level of mass consciousness, then on the unconscious level, certain doubts were traceable, as to the effectiveness of his presidency. The President's activity was estimated by the respondents positively on the whole, though its certain concrete spheres were being given negative estimations. So, it can be asserted, the authors maintain, that citizens expect from Putin more effectiveness in the solution of the state's problems.

Proceedings of the 20th Annual Conference of the Japanese Association for Adolescent Psychotherapy, 16 November 2002, Tokyo, Japan

Proceedings of the 20th Annual Conference of the Japanese Association for Adolescent Psychotherapy, 16 November 2002, Tokyo, Japan

エクステリアフロンティア軌道広がりモデル ジアステレオ面選択性予測のための試み

Based on the simple assumption that π-facial diastereoselection should be originated from the difference in the magnitude of the reaction driving force over the two faces of the π-plane, a new theoretical model is proposed for the prediction of faical diastereoselection. According to the Salem-Klopman equation, two quantities - steric effects (1st term) and the spatial extension of frontier orbital of a substrate ketone (3rd term) - are quantitatively evaluated as the π-plane-divided accessible space (PDAS) and the exterior frontier orbital extension density (EFOE density). The latter is obtained by integrating the frontier orbital (LUMO of a ketone) extension over one side of the π-plane in the exterior area of the van der Waals surface of the ketone under the specific criteria that the driving force vector located on the hydride should be maximally directed toward the carbonyl carbon. Numerous cases of facial diastereoselectivity of hydride reduction including ketones with polar substituents, heterocyclic systems, symmetric bi- or tricyclic ketones, imines, iminium ion are successfully explained by these two new simple quantities. These results as well as quantitative evaluation of transition effects (mainly the antiperiplanar hyperconjugative stabilization involving the incipient bond) strongly suggest that the orbital interaction between reactants generated in the initial stage rather than transition state effects must be the essential process of diastereoselection.

No pain, no gain? The importance of measuring course workload in student ratings of instruction.

Samples of about 200 undergraduate courses were investigated in each of 3 consecutive academic terms. Course survey forms assessed evaluative ratings, expected grades, and course workloads. A covariance structure model was developed in exploratory fashion for the 1st term's data, and then successfully cross-validated in each of the next 2 terms. The 2 major features of the successful model were that (a) courses that gave higher grades were better liked (a positive path from expected grades to evaluative ratings), and (b) courses that gave higher grades had lighter workloads (a negative relation between expected grades and workload). These findings support the conclusion that instructors' grading leniency influences ratings. This effect of grading leniency also importantly qualifies the standard interpretation that student ratings are relatively pure indicators of instructional quality. Student ratings have been both praised as being valid and efficient and criticized as being insensitive and misleading.' The present research proceeds from an intermediate viewthat student ratings may be imperfect but are nevertheless useful and are also improvable through research. The specific aim of the present research was to construct and confirm a covariance structure model that could identify sources of desired or undesired influences on student ratings. The most ambitious previous effort to describe and confirm a covariance structure model of student ratings has been Marsh's (1991) hierarchical confirmatory factor analysis of &ta provided by 35 items of the SEEQ (Student Evaluations of Educational Quality) inventory. Marsh reported substantial confirmatory support for a nine-factor first-order structure overlaid with a four-factor structure in which the higher order factors represented similarity relations among the nine first-order factors. In contrast with Marsh's (1991) aim of analyzing the dimensional structure of student ratings, the present research sought to evaluate theories of causal influences operating on student ratings. Alternative theories of the influences that affect student ratings imply different patterns of relationships among three categories of measures: (a) evaluative ratings, (b) expected grades, and (c) course workloads.

Calbindin-D 9k mRNA expression in 1st trimester and term human placenta

Calbindin-D 9k mRNA expression in 1st trimester and term human placenta

Exogenous Progestins and Breast Cancer

More research on the effect of exogenous progestins on breast cancer risk is clearly needed. Biologic evidence that progestins may act synergistically with estrogen to enhance proliferation of breast epithelial cells emphasizes the importance of further exploration of this issue, particularly given the increasing prevalence of exposure to contraceptive and noncontraceptive progestins. No specific type or dose of progestin in monophasic combination oral contraceptives has been linked to breast cancer. Based on the few epidemiologic studies of progestin-only oral contraceptives, there also is no evidence that they increase risk of breast cancer. Two studies found that longer-term use of progestin-only pills was associated with a decreased risk of breast cancer. However, given the low prevalence of use of minipills, it is unlikely that this exposure substantially affects the incidence of breast cancer in the population as a whole. Use of the injectable contraceptive DMPA has been positively associated with risk of breast cancer in some subgroups of women, although no significant overall adverse effect has been observed in the two largest studies conducted to date. There is suggestive evidence that use at an early age or prior to a first term birth and recent use may increase risk of breast cancer. It remains unclear, however, whether or not surveillance bias may explain the positive association observed in recent users. Additional research on DMPA and breast cancer incidence is needed, since studies published to date have lacked sufficient power to evaluate risk in relation to long-term use. Future studies of breast cancer in relation to use of other long-acting progestational agents such as Norplant will also be important. There is concern about the relation between breast cancer incidence and use of combined estrogen-progestin replacement therapy, especially extended periods of use. At the present time, only one study (45) has estimated risk according to duration of use, and it remains uncertain whether the reported elevation in risk seen in long-term users of combined therapy is due to enhanced surveillance for breast cancer among exposed women. Further research will be required before any definitive conclusions can be reached about the potential effect of estrogen-progestin replacement regimens on breast cancer incidence. Future studies should attempt to determine the circumstances under which progestins may alter risk of breast cancer and whether such effects vary by duration of use, dosage, type of preparation, concomitant use of estrogens, regimen of exposure, and the timing of progestin use in relation to age and menstrual and reproductive events.(ABSTRACT TRUNCATED AT 400 WORDS)

Oral contraceptives and breast disease

Epidemiologic data support the hypothesis that the types of OCs used before the mid-1970s protected against most forms of benign breast disease. It is unclear whether current low-dose progestogen OCs will confer the same protection. Further studies are necessary to clarify this. For breast cancer, the relationship is more complex. It is possible that prolonged use of high-dose OCs exert a small increased risk for breast cancer development in women before age 45. Furthermore, prolonged use before a first term pregnancy may result in a small increase in risk for breast cancer before age 45. Studies evaluating the effect of current low-dose OCs are necessary to elucidate what, if any, effect they may have on breast cancer development. Furthermore, as our population ages, studies will be able to determine what effect, if any, may be present in women over age 60, those women with the highest underlying risk of breast cancer. And finally, more research of basic breast tissue physiology and the effect of endogenous and exogenous hormones on this complex organ is needed.

Induced abortion as cancer risk factor: a review of epidemiological evidence.

The issue of the oncological implications of induced abortion is reviewed based on the limited literature available. 2 conflicting interpretations emerge in understanding the potential risk factors. One view is that any pregnancy interrupted or full term is protective or neutral. The other view is that sudden termination creates hormonal blows to the endocrine immunological neurological and other processes and there is incomplete growth of breast tissues. The statistical results have not been strong enough to determine the nature of the impact and are frequently biased by the attitude of the researcher. There is an apparent lack of information from populations like the USSR with a high induced abortion rate. Questions such as whether the effects during the reproductive years of induced abortion are the same before between or after live births and whether gestational age and type of termination technique influences cancer risk. Cervical and breast cancer relationships to induced abortion have been studied with conflicting results while the very few studies of ovarian and endometrial cancers indicate little or no effect from induced abortion. There is some evidence to suggest that there is a mildly significant relationship controlling for other reproductive factors between induced abortion before 1st full term pregnancy and breast cancers. In the USSR regional variation in induced abortion accounts more for cervical cancer than fertility rates.

Breast cancer and oral contraceptives

Since 1960 over 25 million women in the United States and 150 million worldwide have taken oral contraceptives (OCs). In 1987 130000 women in the United States are expected to be diagnosed with breast cancer and 41000 are expected to die from the disease. However studies have not proven the use of OCs to either increase or decrease the risk of breast cancer. Despite data to the contrary epidemiologists continue to debate whether women who use OCs at an early age or before their 1st term pregnancy have an increased risk. Reports from studies in England Sweden and Los Angeles suggested an increase risk of developing premenopausal breast cancer but later analysis of the studies in England and Los Angeles showed no increase in risk of breast cancer. A study conducted in Scandinavia in 1986 suggested an increase risk of premenopausal breast cancer for women with longterm use and use before 1st term pregnancy but a similar study in New Zealand did not confirm this conclusion. Since current studies have given so many conflicting reports investigators should vigorously pursue studying the longterm effects of OC use and the risk of breast cancer.

Oral Contraceptives and Neoplasia: 1989 Update

The association between oral contraceptives and cancer is updated in this review considering recent studies on benign and malignant breast cancer and ovarian cancer and cysts uterine leiomyomas and trophoblastic disease benign and malignant liver tumors cervical pituitary and endometrial cancer and menopausal estrogens. The review begins with a discussion of investigative methods and epidemiological approaches the most common of which are case reports and tumor registries; disease rates and trends; retrospective case comparisons; and prospective cohort studies. While increasingly sophisticated methods are being applied and the lag time is now beyond that needed to detect carcinogenesis US women have been taking pills with 50 mcg or less of ethinyl estradiol and 1 mg or less of progestin for only 15 years and cancer studies do not reflect this fact. High doses of progestins (>1 mg) protect against benign breast disease; reports are conflicting about breast cancer suggesting that long durations of use before 1st term pregnancy may confer higher risk. While the most important risk factor for cervical cancer is infection with human papilloma virus risk of cervical cancer is heightened by oral contraceptive use in proportion to duration. Combined pills protect against both ovarian cysts and neoplasms; multiphasics may not be as protective against cysts but even past use of pills maintains protection against cancer. Recent data are suggestive of a protective effect of oral contraceptives against uterine fibroids. Low dose pills are not longer considered contraindicated for women having recently had a molar pregnancy removed. While it is known that long-term unopposed or sequential estrogens increase risk of endometrial adenocarcinoma combined pills confer a significant protective effect after 1 year of use. Benign and malignant liver tumors are an extremely rare condition enhanced by long-term use of oral contraceptives. Regression of the adenomas usually follows discontinuation of the pill; whether hepatocellular carcinoma arises from adenoma is yet unproven.

The contraceptive pill and breast cancer in young women.

As more epidemiological studies are done on the effect of oral contraceptives (OCs) on breast cancer, the more unclear the effects are. On the other hand, 9 case control studies demonstrated that combined OCs reduce the risk of endometrial cancer, and 8 case control studies showed a reduced risk of ovarian cancer. It is biologically plausible for there to be a protective effect against these 3 cancers, but as for breast cancer, it is not yet known if combined OCs enhance or antagonize harmful effects of ovarian activity. Researchers conducted a case control study in 11 areas of the United Kingdom consisting of 755 women with breast cancer that had been diagnosed before the age of 36 years. They found an association between the duration of use of combined OCs and the risk of breast cancer (relative risk of 1.74) after 8 years of using combined OCs. The significance of this study was that the association was noted whatever the age at which the combined OCs were taken and was noted both before and after the 1st full term pregnancy. Another new finding included an apparent link between cancer risk and the dose of estrogen: those combined OCs with 50 ug ethinyl-estradiol carried less of a risk, yet some risk was still detectable with low dose pills. Since the researchers restricted the study to women 36 years old, the results may not be relevant to most women with breast cancer, however. Further, the authors of this study bring to the reader's attention that the national breast cancer registration rates are not increasing. This is indeed reassuring.

Breast cancer before age 45 and oral contraceptive use: new findings.

The relation between the risk of breast cancer before 45 years of age and oral contraceptive use was examined in a case-control study conducted in New York, Philadelphia, Baltimore, and Boston from 1983 to 1986 of 407 patients with breast cancer and 424 controls. With allowance for confounding, for ever use, the multivariate relative risk estimate was 2.0 (95% confidence interval (CI), 1.4-2.9). For less than 10 years of use, the estimate approximated 2.0 in all categories of duration, including less than three months; for 10 or more years of use it was 4.1 (95% CI, 1.8-9.3). The association was apparent in virtually all subgroups examined, including younger and older women, and women at low and high underlying risk of breast cancer. Contrary to some previous reports, the association was not stronger for use before a first term pregnancy or at an early age. The results suggest that oral contraceptive users, particularly those with very long durations of use, may be at increased risk of breast cancer. However, information bias, particularly for short-term use, could not be ruled out. There may also have been selection bias if oral contraceptive users were under more intensive medical surveillance. It has not been possible to reconcile the findings of the various studies to date, including the authors' earlier results showing no association. The latter results were derived from data collected using methods almost identical to those used in the present study.

Oral-Contraceptive Use and the Risk of Breast Cancer. The Cancer and Steroid Hormone Study of the Centers for Disease Control and the National Institute of Child Health and Human Development

Data from the Cancer and Steroid Hormone Study of the Centers for Disease Control (CDC) were used to analyze the effect of oral contraceptives (OCs) on the risk of breast cancer in women 20-54 years of age. Cases included 4711 women with newly diagnosed primary breast cancer; 4676 controls were selected through random-digit dialing in the geographic areas of the cases. A higher proportion of cases than controls were nulliparous older at 1st term pregnancy had a history of benign breast disease were premenopausal were younger at menarche and had fewer live births. Overall the relative risk of breast cancer was 1.0 in women who had used OCs compared to never-users; that is no difference between the two groups. Even when OC use was categorized according to both duration of use and time since last use no pattern of association between OC use and breast cancer was apparent. In addition use of specific formulations of OCs and the type of estrogen or progestin in combination OCs were not significant factors. The relative risk of breast cancer was 1.0 both among women who used OCs containing only mestranol and among those who used formulations containing only ethinyl estradiol as the estrogen component. The relative risk of breast cancer among women who had used only combination OCs ranged from0.6 (10 mg norethindrone/60 mcg mestranol) to 1.6 (1 mg norethindrone acetate/50 mcg ethinyl estradiol) but no single preparation was associated with a significantly increased risk. Overall these results provide further support for the contention that OC use does not increase the risk of breast cancer even when the contraceptives have been used for 15 years or longer.

Oral-Contraceptive Use and the Risk of Breast Cancer. The Cancer and Steroid Hormone Study of the Centers for Disease Control and the National Institute of Child Health and Human Development

Data from the Cancer and Steroid Hormone Study of the Centers for Disease Control (CDC) were used to analyze the effect of oral contraceptives (OCs) on the risk of breast cancer in women 20-54 years of age. Cases included 4711 women with newly diagnosed primary breast cancer; 4676 controls were selected through random-digit dialing in the geographic areas of the cases. A higher proportion of cases than controls were nulliparous older at 1st term pregnancy had a history of benign breast disease were premenopausal were younger at menarche and had fewer live births. Overall the relative risk of breast cancer was 1.0 in women who had used OCs compared to never-users; that is no difference between the two groups. Even when OC use was categorized according to both duration of use and time since last use no pattern of association between OC use and breast cancer was apparent. In addition use of specific formulations of OCs and the type of estrogen or progestin in combination OCs were not significant factors. The relative risk of breast cancer was 1.0 both among women who used OCs containing only mestranol and among those who used formulations containing only ethinyl estradiol as the estrogen component. The relative risk of breast cancer among women who had used only combination OCs ranged from0.6 (10 mg norethindrone/60 mcg mestranol) to 1.6 (1 mg norethindrone acetate/50 mcg ethinyl estradiol) but no single preparation was associated with a significantly increased risk. Overall these results provide further support for the contention that OC use does not increase the risk of breast cancer even when the contraceptives have been used for 15 years or longer.