Showing papers by "University of Toronto published in 1978"
TL;DR: The authors report a set of simple experiments that establish the existence of a robust and interesting phenomenon of memory, called the generation effect, which is robust in that it manifests itself across a variety of testing procedures, encoding rules, and other situational changes.
Abstract: Five experiments are reported comparing memory for words that were generated by the subjects themselves with the same words when they were simply presented to be read. In all cases, performance in the generate condition was superior to that in the read condition. This held for measures of cued and uncued recognition, free and cued recall, and confidence ratings. The phenomenon persisted across variations in encoding rules, timed or selfpaced presentation, presence or absence of test information, and between- or within-subjects designs. The effect was specific to the response items under recognition testing but not under cued recall. A number of potential explanatory principles are considered, and their difficulties enumerated. It is concluded that the generation effect is real and that it poses an interesting interpretative problem. This is an empirically oriented article whose purpose is to report a set of simple experiments that establish the existence of a robust and interesting phenomenon of memory. This phenomenon, called the generation effect, is robust in that it manifests itself across a variety of testing procedures, encoding rules, and other situational changes. It is interesting in that it does not seem to be easily or satisfactoril y accommodated by any of the currently familiar explanatory notions. We expect that once the phenomenon is described in its initial form, it will be the subject of wider experimental analysis and will eventually become better understood. In contrast to the usual objective reasons for embarking upon a line of research, the present work was neither initiated by any extant theoretical issue nor inspired by any previously published findings. It was carried out with the sole purpose of arriving at a
1,527 citations
TL;DR: The highly idiosyncratic “anti-task” latency data can be normalized by reference to the Wheeless 2-step paradigm, and the human saccadic system is optimized for, but not restricted to, foveation.
1,192 citations
TL;DR: The sea level rise due to ice-sheet melting since the last glacial maximum was not uniform everywhere because of the deformation of the Earth's surface and its geoid by changing ice and water loads.
737 citations
TL;DR: In this article, the spectrum and mixing angles of negative-parity baryons in a quark-model framework inspired by quantum chromodynamics were discussed, and good agreement with experiment in the $S = 0$ and $S=\ensuremath{-}1$ sectors were obtained.
Abstract: We discuss the spectrum and mixing angles of negative-parity baryons in a quark-model framework inspired by quantum chromodynamics. We take into account in zero order the removal of the degeneracy between the two $P$-wave states of the three-quark system in the $S=\ensuremath{-}1$ sector, as well as the hyperfine interaction between quarks, but neglect spin-orbit coupling. We find good agreement with experiment in the $S=0$ and $S=\ensuremath{-}1$ sectors where there are data and predict the $S=\ensuremath{-}2, \ensuremath{-}3$ sectors.
722 citations
TL;DR: An algebraic technique for embedding abstract data types in programming languages is presented, some of the formal properties of the technique are developed, and it is shown that these provide useful guidelines for the construction of adequate specifications.
Abstract: There have been many recent proposals for embedding abstract data types in programming languages. In order to reason about programs using abstract data types, it is desirable to specify their properties at an abstract level, independent of any particular implementation. This paper presents an algebraic technique for such specifications, develops some of the formal properties of the technique, and shows that these provide useful guidelines for the construction of adequate specifications.
523 citations
TL;DR: In this article, the authors discuss a new method of evaluating the inverse transforms, which is a frequency and wavenumber integral, and discuss some of the advantages of this combination.
Abstract: Summary. The computation of theoretical seismograms for models in which the elastic parameters and density vary only with depth (in a plane, cylindrical or spherical geometry) reduces to the solution of an ordinary differential equation plus the evaluation of inverse transformations. In principle, the problem is straightforward. In practice, many techniques and approximations can be used at each stage and many combinations and variants are possible. In this paper, we discuss a new method of evaluating the inverse transforms. Any method can be used to solve the differential equation and we only discuss a few analytic approximations to illustrate the new method. The inverse transformations are a frequency and wavenumber integral. Essentially four techniques can be used to evaluate these depending on the order of integration and whether the wavenumber integral is distorted from the real axis. Three of these have been widely used, but the technique of evaluating the frequency integral first and keeping the wavenumber real is new. In this paper, we discuss some of the advantages of this combination.
493 citations
469 citations
TL;DR: By measuring dopamine receptors in the putamen and caudate of postmortem brains from Parkinson patients, evidence is reported in support of the theory of dopaminergic supersensitivity in Parkinson's disease.
Abstract: IN patients with Parkinson's disease, the concentration of dopamine in the basal ganglia of the brain is markedly reduced in accordance with the degeneration of the nigrostriatal dopamine-containing neurones1,2. This fact provided the basis for the successful clinical introduction of L-dopa (L-3,4-dihydroxyphenylalaline) for Parkinson's disease3,6. It has been suggested that one of the critical factors compensating for the loss of dopamine neurones may be the development of “denervation supersensitivity” in the striatum, as severe cases react more sensitively to L-dopa than milder cases or controls7–9. By measuring dopamine receptors in the putamen and caudate of postmortem brains from Parkinson patients, we report here evidence in support of the theory of dopaminergic supersensitivity in Parkinson's disease.
466 citations
TL;DR: The authors examines some of the reasons for the maintenance and persistence of family labour farms within agricultural sectors of advanced capitalist countries: some obstacles to the development of a capitalist agriculture are highlighted, and suggests that the peculiar nature of the productive process in certain spheres of agriculture is incompatible with the requirements of capitalist production and therefore makes these spheres unattractive for capitalist penetration.
Abstract: This paper examines some of the reasons for the maintenance and persistence of family labour farms within agricultural sectors of advanced capitalist countries: some obstacles to the development of a capitalist agriculture are highlighted. The survival of family farms has called into question Marx's theory of the transitional nature of petty commodity production; hence, Marxism is generally regarded as being unable to account for the viability of family farms. Two theories commonly advanced to explain this phenomenon are examined and found to be inadequate. This paper suggests that a closer examination of Marx's writings reveals how the peculiar nature of the productive process in certain spheres of agriculture is incompatible with the requirements of capitalist production and, therefore, makes these spheres unattractive for capitalist penetration. Here the implications of Marx's distinction between production time and labour time for the development of a capitalist agriculture are discussed. Specifically...
452 citations
TL;DR: These procedures nearly achieve recently established lower bounds on the amount of space inherently required to solve the covering and boundedness problems for vector addition systems, and so are much more efficient than previously known non-primitive-recursive decision procedures.
426 citations
TL;DR: The determination of setal homologies and setal platterns on the dorsal shield in the family phytoseidae (Acarina: Mesostigmata) is determined.
Abstract: The chaetotactic nomenclature proposed by Lindquist and Evans (1965) for the Gamasina, using the family Ascidae as examplar, is adopted for use in the family Phytoseiidae. Probable setal homologies were determined by: examining and comparing ontogenetic relationships in both the Phytoseiidae and Ascidae; standardizing the shape and size of the dorsal shield of exemplars from 7 genera of Phytoseiidae and one of Ascidae in order to compare standardized, transformed setal positions; examining the spatial relationships between setal and pore positions. The technique used to standardize the shape and size of the dorsal shield is described. The setal nomenclature adopted for each of the genera of Phytoseiidae is discussed and presented in diagrammatic form. Ventral chaetotaxy in the Ascidae and Phytoseiidae is also discussed.
TL;DR: Eight chronic alcoholics received repeated computed tomography scans and four, who maintained abstinence and functionally improved, showed partially reversible cerebral atrophy.
Abstract: Eight chronic alcoholics received repeated computed tomography scans. Four, who maintained abstinence and functionally improved, showed partially reversible cerebral atrophy. Two nonabstinent patients and two abstinent patients who had completed functional improvement before the first scan showed no change in atrophy.
TL;DR: A new approach to the sequential analysis of carcinogenesis in vivo is developed that delineates the first few steps in the process and is a quantitative assay for initiation of liver cancer, to investigate whether cell replication exerts its first effect on initiation or on some later step in the carcinogenic process.
Abstract: CELL proliferation has often been implicated in the development of cancer with chemicals1–3. Supportive evidence for this is the observation that several carcinogens that normally do not induce liver cancer in intact adult animals, especially with a single dose, become carcinogenic if administered as a single injection after partial hepatectomy (PH)1. In these conditions, it is thought that PH may act during initiation, presumably by fixation of some carcinogen-induced DNA damage through replication of the altered DNA. However, because carcinogenesis is a multi-step process, often involving the appearance of several new cell populations between the initial target cells and the ultimate cancer4,5, it is possible that the regenerative response of liver following PH could have a major effect on one or more steps subsequent to initiation. Thus, the use of a very late end-point (cancer) makes it difficult, if not impossible, to relate with any accuracy some very early event to any specific step in the carcinogenic process. Solt and Farber6 have recently developed a new approach to the sequential analysis of carcinogenesis in vivo that delineates the first few steps in the process and is a quantitative assay for initiation of liver cancer. We have used this model to investigate whether cell replication exerts its first effect on initiation or on some later step in the carcinogenic process. And if initiation is at least one site of action, when in the regenerative cell cycle is a carcinogen most effective and what biochemical events might be involved at this phase of the cell cycle?
TL;DR: Direct evidence for some abnormalities in brain dopamine receptors in schizophrenia is obtained by measuring the specific binding of3H-apomorphine and 3H-haloperidol or 3H -spiperone to four regions of postmortem brains from schizophrenic patients.
Abstract: THE neuroleptic or antipsychotic drugs, introduced in 19521, effectively prevent relapse and rehospitalisation of schizophrenic patients. These drugs provide a strategy2 for localising possible abnormalities in the brain in schizophrenia. The hypothesis that schizophrenia might be associated with abnormally sensitive dopamine synapses3–6 evolved from the suggestion that neuroleptics block dopamine receptors and thus accelerate the turnover of dopamine7,8. The hypothesis received additional support from the observations that dopamine-mimetic drugs (for example d-amphetamine, L-dopa) elicit or exacerbate psychotic symptoms9–12, that neuroleptics produce supersensitivity to dopamine13–15, that the neuroleptic and antipsychotic actions are enhanced by drugs which block the synthesis of catecholamines16, that neuroleptics all have conformations that match that of dopamine17, and that dopamine is the most potent neurotransmitter to inhibit the specific binding of 3H-haloperidol to dopamine-rich regions of the brain18–20. Although all this evidence for the dopamine hypothesis of schizophrenia is circumstantial, we have now obtained direct evidence for some abnormalities in brain dopamine receptors in schizophrenia by measuring the specific binding of 3H-apomorphine and 3H-haloperidol or 3H-spiperone to four regions of postmortem brains from schizophrenic patients.
TL;DR: In this paper, the attention demands of mental operations within the choice task can be assessed by extending Sternberg's additivefactors method, and the important effects are the interactions of classification-task parameters with memory load.
Abstract: SUMMARY Most theories of attention predict that engaging a subject in demanding concurrent activity will increase choice reaction time by an amount proportional to the attention demands of the choice task. The attention demands of mental operations within the choice task can be assessed by extending Sternberg's additivefactors method. Parameters associated with those processing stages that demand attention will interact with the amount of concurrent activity (i.e., will have greater effects with concurrent activity than without), but parameters associated with automatic processing stages will not (i.e., the joint effects will be additive). This analysis was applied to eight character-classification experiments. The classification task was either performed alone or in the retention interval of a short-term memory task which required ordered recall of 7 digits. According to the extended additive-factors method, the important effects are the interactions of classification-task parameters with memory load. The first two experiments reported validate the method with a memory-search task. Interactions were obtained between memory load and target-set size whose magnitude depended on the amount of practice with specific target sets. Inferences about attention demand and automaticity were shown to be consistent with those drawn from another criterion for automaticity, based on a different aspect of the data. The remaining six experiments examined four stages sufficient to perform a visual-search task (encoding, comparison, decision, and response selection). Memory load did not interact with parameters associated with encoding, decision and response-selection stages, and of three parameters associated with the comparison stage (target-set size, array size, and the presence or absence of a bar marker indicating the target's position), only target-set size interacted with memory load (Experiments 1 and 2). It was concluded that most of the processing involved in character classification does not require attention, and this was taken as evidence against models that identify attention with specific processingstructures. The results were interpreted as supporting the view that attention is a limited capacity to activate processing structures internally, and the role of attention in preparing, maintaining, and executing mental operations is discussed.
TL;DR: For example, between 1873 and 1935 dramatic changes took place in the character of production in the industrial nations of the world as discussed by the authors and the new social importance of wage laborers, while certainly not the only features of the era, are often viewed as its central, interrelated, and dynamic basis.
Abstract: Between 1873 and 1935 dramatic changes took place in the character of production in the industrial nations of the world. Longstanding and newly formed states in Europe and America engaged in vigorous campaigns of territorial expansion, so that virtually all the globe came to be incorporated within the sphere of world markets. During the same period, the expansion in industrial countries of new techniques of mass production coincided with growth and consolidation of organizations of people who worked for wages. The expansion of world markets, the development of mass produc— tion, and the new social importance of wage laborers, while certainly not the only features of the era, are often viewed as its central, interrelated, and dynamic basis.1 In this context, the transformations of production which accompanied the rise of a world wheat market during these decades were quite unusual.
TL;DR: This chapter discusses the metabolism of molecular species of diacylglycerophospholipids, which is intimately involved with the activity of the acyl transferases and can yield beneficial results in the treatment of membrane diseases.
Abstract: Publisher Summary This chapter discusses the metabolism of molecular species of diacylglycerophospholipids. The glycerolipid composition of cell membranes and lipoproteins is metabolically adjusted to meet specific requirements, and it does not merely reflect the supply of different fatty acids in the diet or in the cell culture medium. However, adequate adjustment cannot always be possible, and under such conditions, the cellular activity can take place in a suboptimal physicochemical environment and characteristic symptoms of a disease state can appear. As the cellular lipid composition is subject to considerable dietary and pharmacological manipulation, there can be therapeutic alterations in the composition of the molecular species of the tissues and other animal species. The metabolism of the molecular species of the glycerophospholipids is intimately involved with the activity of the acyl transferases. Therapeutic alterations in the composition of the molecular species of the glycerolipids can be feasible and can yield beneficial results in the treatment of membrane diseases.
TL;DR: Fibrinogen is required for ADP-induced aggregation of washed human platelets and enhances ADP induced aggregation of rabbit platelets as discussed by the authors, but it is not required to be present before ADP was added or added with the ADP.
TL;DR: The combined light and electron microscopic study shows that marked, possibly irreversible changes may be present in the lungs of patients with severe bronchial asthma, even when they are asymptomatic.
Abstract: This study describes the histopathology and ultrastructure of bronchial mucosa in lung biopsies from two children with bronchial asthma in remission, and compares them with lung samples from two children who died in status asthmaticus. Light microscopy of all samples showed changes typical of bronchial asthma, e.g. mucus plugging, goblet cell hyperplasia, ‘thickening of bronchial basement membrane’, peribronchial smooth muscle hypertrophy and eosinophilic infiltration. Electron microscopy revealed that the mucus plugs consisted of moderately electron-dense floccular material containing degenerate epithelial cells, macrophages and cell fragments. The luminal surfaces of ciliated cells showed cytoplasmic blebs and abnormal cilia. Mast cells in various stages of degranulation were scattered between bronchial epithelial cells. The subepithelial hyaline layer, commonly referred to as “thickened basement membrane”, consisted of collagen fibrils in plexiform arrangement. The basement membrane proper appeared intact. These electron microscopic changes, particularly the presence of mast cells and subepithelial collagen deposits, were also found in autopsy samples. This combined light and electron microscopic study shows that marked, possibly irreversible changes may be present in the lungs of patients with severe bronchial asthma, even when they are asymptomatic. These pulmonary changes could be the direct consequence of mast cell activation and the release of various mediators. No evidence of immune complex deposition was found.
TL;DR: It is not yet clear whether the relation between the length of treatment and the persistence of supersensitivity holds for very long treatments but in principle the relationship might account forThe persistence of tardive dyskinesia after years of neuroleptic pretreatment.
Abstract: It is known that a single dose of a neuroleptic can elicit dopaminergic supersensitivity in animals. On the other hand, the clinical syndrome of tardive dyskinesia takes many months of years to develop. To resolve this apparent discrepancy, it is possible that subclinical or latent tardive dyskinesia is fully compensated in most patients taking neuroleptics. In others, where the tardive dyskinesia is full-blown and grossly apparent, the dopaminergic supersensitivity may be decompensated. Such compensatory and decompensatory phases have been proposed earlier by Hornykiewicz (1974), in the case of Parkinson's Disease. Dopaminergic supersensitivity persists for a period proportional to the lenght of the neuroleptic treatment. It is not yet clear whether the relation between the length of treatment and the persistence of supersensitivity holds for very long treatments, but in principle the relationship might account for the persistence of tardive dyskinesia after years of neuroleptic pretreatment.
TL;DR: In postmortem examination of brains of patients with chronic paranoid schizophrenia, above-normal norepinephrine levels were measured in the ventral septum, the bed nucleus of the stria terminalis, the nucleus accumbens, and the mammillary bodies, suggesting the possibility of a malfunction of limbic noradrenergic mechanisms in schizophrenia, especially the paranoid variety.
Abstract: In postmortem examination of brains of four patients with chronic paranoid schizophrenia, above-normal norepinephrine levels were measured in the ventral septum, the bed nucleus of the stria terminalis, the nucleus accumbens, and the mammillary bodies. No changes were detected in other limbic forebrain regions, including the hypothalamus and the medial olfactory (preoptic) area. The results point to the possibility of a malfunction of limbic noradrenergic mechanisms in schizophrenia, especially the paranoid variety.
TL;DR: In this article, a longitudinal study of 51 weanlings from 5 litters of Wistar rats was undertaken to characterize the time course of the spontaneous diabetic syndrome, and new features identified are: 1) a time course evolution from normoglycaemia to overt diabetes telescoped into a period of days, and 2) a “chemical” stage or form with an insulitis similar to that found in the early stages of overt diabetes.
Abstract: A longitudinal study of 51 weanlings from 5 litters of “BB” Wistar rats was undertaken to characterize the time course of the spontaneous diabetic syndrome. Nine rats developed overt diabetes. An abnormal glucose tolerance preceded the onset of the syndrome in 6 of these 9 rats. No other “clinical” or metabolic variable measured was predictive of the development of this syndrome. In these rats, the onset was remarkably abrupt, followed by rapid clinical deterioration with marked hyperglycaemia, glycosuria, ketonaemia and hypoinsulinaemia attained within 2 to 8 days. Pronounced insulitis was present in the early stages of the syndrome, resulting in complete B-cell destruction at the time of sacrifice at 7 to 40 days. Among the 42 littermates, 9 revealed sequential abnormalities in oral glucose tolerance tests performed at weekly intervals (to age 90–120 d) though remaining aglycosuric and maintaining normal fasting plasma glucose levels. In 7 of these rats, a milder form of the same islet inflammatory lesion seen in the overtly diabetic animals was present. Thus the new features identified are: 1) a time course of evolution from normoglycaemia to overt diabetes telescoped into a period of days, and 2) a “chemical” stage or form with an insulitis similar to that found in the early stages of overt diabetes.
TL;DR: Ecgonine methyl ester, a product of cocaine hydrolysis by plasma cholinesterase, was identified as a major metabolite in the urine of both subjects and accounted for 32% to 49% of the urinary metabolites.
Abstract: Following ingestion of [N-14CH3]cocaine (10 mg, 2.3 muCi) by 2 healthy subjects, breath, saliva, serum, and urine samples were collected serially. Labeled CO2 production was monitored as a measure of N-demethylation of cocaine. The cumulative excretion of 14CO2 in 5 hr was 2.4% and 6.2% of the administered dose with half-lives of 2.3 and 1.4 hr, respectively. The greater N-demethylation was found in a subject with lower plasma cholinesterase activity. Radioactivity excreted in 0 to 28 hr urine reached 65% to 75% of the dose. Ecgonine methyl ester, a product of cocaine hydrolysis by plasma cholinesterase, was identified as a major metabolite in the urine of both subjects and accounted for 32% to 49% of the urinary metabolites.
TL;DR: Immunological evidence is reported here immunological evidence that VIP, or a closely related peptide, occurs in mast cells, from which it can be released by compound 48/80 or by the Ca2+ ionophore A23187.
Abstract: VASOACTIVE INTESTINAL POLYPEPTIDE (VIP), originally isolated from porcine duodenum1, is a potent relaxant of vascular and nonvascular smooth muscle2, and a stimulant of adenylate cyclase activity3,4. The peptide has been localised in endocrine cells in the gastrointestinal tract and pancreatic islets5,6, as well as in nervous structures in these and other organs7–9, the peripheral autonomic nervous system and selected areas of the brain8–11. We report here immunological evidence that VIP, or a closely related peptide, occurs in mast cells, from which it can be released by compound 48/80 or by the Ca2+ ionophore A23187.
TL;DR: Evidence of an association between an increased intake of nutrients, especially total fat, in both pre- menopausal and post-menopausal women with breast cancer and its consistency with other evidence, both experimental and international, suggests that it is causal.
Abstract: A case-control study has been conducted in four areas in Canada in which 400 cases of breast cancer matched by age and marital status with neighborhood controls were administered a medical and dietary history questionnaire, a 24-hour recall for dietary information and a four-day diet record. The Study has produced evidence of an association between an increased intake of nutrients, especially total fat, in both pre-menopausal and post-menopausal women with breast cancer. Reasons why a weak association might have been anticipated are discussed, and it is concluded that in reality the association is stronger. Furthermore, its consistency with other evidence, both experimental and international, suggests that it is causal.
TL;DR: Some tumor cells have been demonstrated by this method to be glial despite the complete lack of blue fibrillar staining with PTAH and the absence of all morphological similarity to glial cells.
Abstract: Eighty glial and non-glial brain tumors have been studied to date using an immunologically specific and highly sensitive method of staining GFA protein which is applicable to formalin fixed and paraffin embedded tissue. Eight of these cases have been described and illustrated in some detail. GFA protein was present in all astrocytes and astrocytomas studied and in a proportion of ependymal cells and ependymomas. Some tumor cells have been demonstrated by this method to be glial despite the complete lack of blue fibrillar staining with PTAH and the absence of all morphological similarity to glial cells. In such cases the demonstration of GFA protein by this method has been valuable in establishing a diagnosis. In addition to its diagnostic value in specific cases, the method promises to shed light on unsolved problems of tumor cytogenesis.
TL;DR: The results provide direct evidence of presynaptic and postsynaptic dopamine receptors in rat brain and the effects of selective lesions of the NSP on labelling of DA receptors in these structures are examined.
Abstract: CENTRAL dopamine (DA)-containing neurones are thought to be involved in several human diseases including Parkinson's disease and schizophrenia, and to act as sites of action of some drugs of abuse. One of these DA systems, the nigrostriatal projection (NSP), has its origin in the substantia nigra (SN), pars compacta and innervates the caudate-putamen (CP). In the SN the dendritic processes of DA neurones have been shown to contain DA and vesicles1–3 and there is evidence that DA can be released by cells in the SN4–6. It has therefore been proposed that one mechanism by which the activity of DA neurones is regulated is through the action of dendritically released DA on hypothesised ‘autoreceptors’ on DA perikarya or dendrites7–9. Recently, however, this view has been challenged by the observation that DA-sensitive adenylate cyclase, an enzyme thought to be coupled with the DA receptor10, is located on terminals of the striatonigral or pallidonigral projection11,12 rather than on the DA cells themselves13–15. Similarly, in the CP where the existence of autoreceptors on DA terminals has been suggested16, the DA-sensitive adenylate cyclase has been shown to be localised on postsynaptic structures rather than on the DA terminals17,18. An established method for studying the DA receptor involves measuring DA receptor binding with labelled DA agonists or antagonists19,20. To further elucidate the location of DA receptors in the SN and CP, we have examined the effects of selective lesions of the NSP on labelling of DA receptors in these structures. These lesions, which are placed in the axons of the NSP, are known to cause near-complete anterograde and retrograde degeneration of the terminals and cell bodies of this system21. The advantage of this lesion technique over previous approaches is that it avoids nonspecific damage of the areas studied. Our results provide direct evidence of presynaptic and postsynaptic dopamine receptors in rat brain.
TL;DR: A case-control study in four areas of Canada is suggestive of an increased risk of breast cancer in post-menopausal women with younger age at menarche and an increase risk with delay of age at natural menopause, and a weak association with increased height and weight as risk factors for breast cancer.
Abstract: A case-control study has been conducted in four areas of Canada in which 400 cases of breast cancer matched by age and marital status with neighborhood controls were administered medical and dietary questionnaires. The study is suggestive of an increased risk of breast cancer in post-menopausal women with younger age at menarche and an increased risk with delay of age at natural menopause. No protective effect of early age at first pregnancy was demonstrated in either pre- or post-menopausal women. An increased frequency of pregnancies of four months duration or less was found in cases compared to controls and a greater frequency in pre-menopausal cases compared to controls of a history of irregular menstrual periods. In pre-menopausal women no association has been found between increased height and weight as risk factors for breast cancer. For post-menopausal women, however, a weak association with increased height has been found, while a strong association with increased weight both at the time of menopause and the 12 months preceding diagnosis has ben confirmed.