Relationship between neural activation and electric field distribution during deep brain stimulation.

Models and simulations are commonly used to study deep brain stimulation (DBS). Simulated stimulation fields are often defined and visualized by electric field isolevels or volumes of tissue activated (VTA). The aim of the present study was to evaluate the relationship between stimulation field strength as defined by the electric potential V, the electric field E, and the divergence of the electric field ∇(2) V, and neural activation.

Deep brain stimulation of the pallidum internum for Gilles de la Tourette syndrome: a patient-specific model-based simulation study of the electric field.

Objectives: The aim of this study was to investigate the deep brain stimulation (DBS) electric field distribution in proton-density MRI scans visualizing the globus pallidus internus (GPi) of patients with Gilles de la Tourette syndrome (GTS), along with its relation to the anatomy.

Methods: Patient-specific brain tissue models (n = 7) with bilateral DBS electrodes in the GPi were set up using the finite element method in five patients who had undergone stereotactic proton-density MRI-guided surgery and showed variable improvement with DBS. Simulations (n = 27) of the electric field were performed and the results visualized on the respective preoperative stereotactic MRI scans.

A diffusion tensor-based finite element model of microdialysis in the deep brain.

Microdialysis of the basal ganglia was recently used to study neurotransmitter levels in relation to deep brain stimulation. In order to estimate the anatomical origin of the obtained data, the maximum tissue volume of influence (TVImax) for a microdialysis catheter was simulated using the finite element method. This study investigates the impact of brain heterogeneity and anisotropy on the TVImax using diffusion tensor imaging (DTI) to create a second-order tensor model of the basal ganglia.

Simulations and visualizations for interpretation of brain microdialysis data during deep brain stimulation.

Microdialysis of the basal ganglia was used in parallel to deep brain stimulation (DBS) for patients with Parkinson's disease. The aim of this study was to patient-specifically simulate and visualize the maximum tissue volume of influence (TVI(max)) for each microdialysis catheter and the electric field generated around each DBS electrode. The finite element method (FEM) was used for the simulations.

A model for simulation and patient-specific visualization of the tissue volume of influence during brain microdialysis.

Microdialysis can be used in parallel to deep brain stimulation (DBS) to relate biochemical changes to the clinical outcome. The aim of the study was to use the finite element method to predict the tissue volume of influence (TVI(max)) and its cross-sectional radius (r (TVImax)) when using brain microdialysis, and visualize the TVI(max) in relation to patient anatomy. An equation based on Fick's law was used to simulate the TVI(max).

Estetrol review: profile and potential clinical applications.

In this review paper, the existing information on the human fetal steroid estetrol (E4) has been summarized. In the past, E4 was considered as a weak estrogen and interest disappeared. However, recent new research has demonstrated that E4 is a potent, orally bioavailable, natural human fetal selective estrogen receptor modulator, since it acts in the rat as an estrogen on all tissues investigated except breast tumor tissue, where it has estrogen antagonistic properties in the presence of estradiol.

Estetrol: a unique steroid in human pregnancy.

Estetrol (E(4)) is an estrogenic steroid molecule synthesized exclusively by the fetal liver during human pregnancy and reaching the maternal circulation through the placenta. Its function is presently unknown. After its discovery in the mid-1960s, E(4) research revealed rather unique properties of this steroid and spawned a large body of state-of-the art publications.

The AMPPA network as a successful model for public-private or private-private partnership.

In 1997, the Rockefeller Foundation and the Ernst Schering Research Foundation (a subsidiary of Schering AG, Germany, on a non-profit basis) mounted a multi-year global collaborative effort, involving a network of top-level research institutions to intensify research on the regulation of the male reproductive system with special emphasis on post-testicular activity, utilizing new approaches in molecular pharmacology (application of molecular pharmacology for post-testicular activity (AMPPA) network). The new venture proved a success as a public-private sector partnership, as a collaborative scientific program, and as an approach to identify new targets applicable and suitable for drug finding for male fertility regulation.

Contraception and society.

When an idea meets the exigencies of an epoch, it becomes stronger than any form of political power and it becomes the common property of humankind. Such an idea was the development of contraceptives. In retrospect, the invention of contraceptives was as fundamental for the evolution of humankind as the invention of the wheel; today more than 550 million couples are using contraceptive methods.

The demographic revolution and our common future.

The global population reached two billion people in 1927 and six billion in 1999. If the medium variant projection of the United Nations were to materialize, the Earth's population would reach nine billion in 2054. However, such a brave new world will be inhabited by a brave old humankind; in 2050, 16.

From the contraceptive to the anthropocentric revolution (Gregory Pincus in memoriam).

The author has seen more progress in science and technology than all scientists of all preceding periods together since the dawn of history and has witnessed a number of powerful revolutions (e.g. scientific, information, postindustrial, globalization, environmental, contraceptive, reproductive health, gender equity and demographic) that have profoundly changed the world and our perception of it.

The past, present and future.

My generation has seen more progress in science and technology than all preceding generations together. We have also witnessed several intellectual, technological, medical and social revolutions spearheaded by the contraceptive revolution and followed by those in reproductive health, gender equity, information, communication, globalization, international assistance, etc. The results of the first contraceptive revolution were spectacular, by 1990 some 900 million couples used contraception, which became a global lifestyle.

In search of human dignity: gender equity, reproductive health and healthy aging.

This paper analyzes the nine pillars of human dignity (sufficient food, potable water, shelter, sanitation, health services, healthy environment, education, employment and personal security), which humankind tries to establish by following nine approaches to reality (scientific, cultural, religious, ethical, economical, ecological, socio-critical, philosophical and political) in a world drastically changed by nine revolutions (demographic, scientific, technological, communication, global identity, environmental, contraceptive, reproductive health and gender equity). The author's generation participated in these revolutions and contributed to the global intellectual process by which gender equity and reproductive health assumed a central role in world affairs. A rapidly aging world population constitutes another major challenge.

Women and the third and fourth age.

In 1900, the world population was less than 1.7 billion people; the United Nations projects that in 2000 it will be 6.2, and in 2020, 7.