19th Century mechanical models of eye movements, Donders’ law, Listing’s law and Helmholtz’ direction circles

Donders, Ruete, von Graefe, von Helmholtz, Listing, Volkmann and many others have provided the broad outline of an answer to the question how the eye rotates during eye movements. Many mechanical models of eye movements, ophthalmotropes, have been constructed and studied in the nineteenth century. These models have primarily served to explain Donders’ and Listing’s Laws on the nature of eye movements. As both Donders’ Law and Listing’s Law are easier to understand when seen against the background of the coordinate systems used to describe eye movements, all of the coordinate systems currently in use in the diagnosis and treatment of strabismus are described. In addition, the reader is introduced to a coordinate system based on von Helmholtz’ direction circles, circles describing the direction of the horizontal and vertical retinal meridians in all positions of gaze

A prospective study on obesity and subcutaneous fat patterning in relation to breast cancer in post-menopausal women participating in the DOM project.

The associations of body fat and body fat distribution with breast cancer risk were examined in a prospective study in 9,746 post-menopausal women with a natural menopause, aged 49-66 at intake, participating in a breast cancer screening project (the DOM project in Utrecht). During a follow-up period of 15 years (mean follow-up time 12.5 years) 260 women developed breast cancer. Fat distribution, assessed by contrasting groups of subcapsular and triceps skinfold thickness, was found to be unrelated to breast cancer incidence. No significant relationship between body fat, measured either by weight, Quetelet's index, triceps skinfold or subscapular skinfold, and breast cancer risk was found when analysed in quartiles. However, women in the upper decile compared with the lower decile of the distribution of Quetelet's index were found to have a 1.9 times (95% CI 1.1-3.3) higher risk for breast cancer. These results seemed to be in contrast with the significant positive association between fatness, analysed in quartiles, and breast cancer observed in a cross-sectional study, based on mammographic screening, carried out previously in the same population. Although the differences between the present, prospective, study and our cross-sectional study may be due to chance it may be that there are differences between characteristics of breast cancer detected at screening and subsequently, which influence the associations between measures of fatness and risk of breast cancer

Validity of self-reported causes of subfertility

The authors assessed the accuracy of cause(s) of subfertility as reported by women in a self-administered questionnaire in comparison with medical record information, in a nationwide cohort study of women receiving in vitro fertilization treatment in the Netherlands (n = 9,164) between 1983 and 1995. Validity was expressed as sensitivity and specificity, and reliability was expressed by the kappa statistic and overall agreement between self-reports and medical records for various subfertility categories. The sensitivity for subfertility attributed to tubal, male, hormonal, cervical, uterine, and idiopathic factors and for endometriosis was 84%, 78%, 65%, 40%, 46%, 59%, and 83%, respectively. The corresponding kappas were 0.79, 0.71, 0.38, 0.34, 0.13, 0.50, and 0.52, respectively. For 54% of all women who reported two or more causes of subfertility, the medical record revealed only one major factor. Conversely, for 43% of all women whose subfertility was attributed to two or more major factors in the record, only one factor was reported by the women. Older age at the time of filling out the questionnaire, low educational level, long duration of subfertility, and pre-in vitro fertilization treatment were associated with less accurate reporting. The results indicate that the validity of self-reports for tubal and male subfertility is satisfactory. For unexplained subfertility, the validity is moderate; for other causes of subfertility and when two causes of subfertility play a role, the validity is low. Copyrigh

Phytoestrogens

Collectively, plants contain several different families of natural products among which are compounds with weak estrogenic or antiestrogenic activity toward mammals. These compounds, termed phytoestrogens, include certain isoflavonoids, flavonoids, stilbenes, and lignans. The best-studied dietary phytoestrogens are the soy isoflavones and the flaxseed lignans. Their perceived health beneficial properties extend beyond hormone-dependent breast and prostate cancers and osteoporosis to include cognitive function, cardiovascular disease, immunity and inflammation, and reproduction and fertility. In the future, metabolic engineering of plants could generate novel and exquisitely controlled dietary sources with which to better assess the potential health beneficial effects of phytoestrogens

Why did Donders, after describing pseudotorsion, deny the existence of ocular counterrolling together with Ruete, Volkmann, von Graefe and von Helmholtz, until Javal reconfirmed its existence?

After the rapid spread of strabismus surgery by total tenotomy, which had been proposed by the orthopedist Louis Stromeyer from Göttingen in 1838 and performed by the plastic surgeon Johann Friedrich Dieffenbach on October 26th and by the ophthalmologist Florent Cunier on October 29th, 1839, brilliant researchers studied the physiology of eye movements, resulting in the laws by Franciscus Cornelis Donders on pseudotorsion in tertiary positions of gaze and by Johann Benedict Listing that each eye position can be reached by rotation about an axis perpendicular to the primary and the new position of gaze. John Hunter had first described ocular counterrolling (OCR) with head tilt in 1786. The anatomist Alexander Friedrich von Hueck inferred from anatomical studies, however, that up to 28.6° OCR would be possible onhead-tilt to right or left shoulder in 1838, and estimated his own OCR seen in a mirror at approximately 25°. Donders, Christian Georg Theodor Ruete, Alfred Wilhelm Volkmann, Albrecht von Graefe and Hermann von Helmholtz subsequently denied the existence of OCR for many years and thought that only pseudotorsion existed. Louis Emile Javal had myopia and astigmatism, and he re-established the existence of OCR in 1867 when he noticed that, on head tilt to either shoulder, the axis of astigmatism of his eyes no longer coincided with the axis of astigmatism of his glasses

Body silhouette, menstrual function at adolescence and breast cancer risk in the E3N cohort study

We analysed the relation between adult breast cancer risk and adiposity in ages 8–25, and among 90 509 women included in the E3N cohort study, and investigated the potential modification effect of certain factors. Participants completed a questionnaire that included a set of eight silhouettes corresponding to body shape at different ages. During the follow-up (mean=11.4 years), 3491 breast cancer cases were identified. Negative trends in risk of breast cancer with increasing body silhouettes at age 8 and at menarche were observed, irrespective of menopausal status, with relative risks of 0.73 (0.53–0.99) and 0.82 (0.66–1.02) for women who reported a silhouette equal or greater than the fifth silhouette at age 8 and at menarche, respectively. We observed no clear effect modification by age at menarche, delay between age at menarche, regular cycling, regularity of cycles in adult life or body mass index at baseline

Breast cancer risk in relation to urinary and serum biomarkers of phytoestrogen exposure in the European Prospective into Cancer-Norfolk cohort study

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract Introduction Phytoestrogens are a group of compounds found in plants that structurally resemble the hormone oestradiol, and thus have the potential to act as oestrogen agonists or antagonists. Their potential effects may alter the risk of breast cancer, but only a limited range of phytoestrogens has been examined in prospective cohort studies. Methods Serum and urine samples from 237 incident breast cancer cases and 952 control individuals (aged 45 to 75 years) in the European Prospective into Cancer-Norfolk cohort were analysed for seven phytoestrogens (daidzein, enterodiol, enterolactone, genistein, glycitein, o-desmethylangolensin, and equol) using liquid chromatography/mass spectrometry. Data on participants' diet, demographics, anthropometrics, and medical history were collected upon recruitment. All models were adjusted for weight, fat and energy intake, family history of breast cancer, social class, analytical batch, and factors related to oestrogen exposure. Results Urinary or serum phytoestrogens were not associated with protection from breast cancer in the European Prospective into Cancer-Norfolk cohort. Breast cancer risk was marginally increased with higher levels of total urinary isoflavones (odds ratio = 1.08 (95% confidence interval = 1.00 to 1.16), P = 0.055); among those with oestrogen receptor-positive tumours, the risk of breast cancer was increased with higher levels of urinary equol (odds ratio = 1.07 (95% confidence interval = 1.01 to 1.12), P = 0.013). Conclusion There was limited evidence of an association between phytoestrogen biomarkers and breast cancer risk in the present study. There was no indication of decreased likelihood of breast cancer with higher levels of phytoestrogen biomarkers, but the observation that some phytoestrogen biomarkers may be associated with greater risk of breast cancer warrants further study with greater statistical power