SEARCH · Search PubMed

Results for “collaborative cross”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84Linked to original sources

PubMed1998

GDB: the Human Genome Database.

The Genome Database (GDB, http://www.gdb.org ) is a public repository of data on human genes, clones, STSs, polymorphisms and maps. GDB entries are highly cross-linked to each other, to literature citations and to entries in other databases, including the sequence databases, OMIM, and the Mouse Genome Database. Mapping data from large genome centers and smaller mapping efforts are added to GDB on an ongoing basis. The database can be searched by a variety of methods, ranging from keyword searches to complex queries. Major functionality extensions in the last year include the ongoing computation of integrated human genome maps, called Comprehensive Maps, and the use of those maps to support positional queries and graphic displays. The capabilities of the GDB map viewer (Mapview) have been extended to include map printing and the graphical display of ad hoc query results. The HUGO Nomenclature Committee continues to curate the proposed and official gene symbols and related data in collaboration with GDB. As genome research shifts its emphasis from mapping to sequencing and functional analysis, the scope of the GDB schema is being extended. We are in the process of adding representations of gene function and expression, and improving our representation of human polymorphism and mutation.

Animals↗

PubMed1994

Confounding results of Lp(a) lipoprotein measurements with some test kits.

A small number of recent studies have reportedly failed to detect the well-established association between a high Lp(a) lipoprotein level and coronary heart disease (CHD). This has made some workers question the importance of a high Lp(a) lipoprotein level as a CHD risk factor. However, serious problems with some of the commercially available test kits, inadequate test techniques or failure to consider the lability of the Lp(a) lipoprotein particle are more plausible explanations of the confounding results. The problems with some of the commercially available test kits include lack of standardization and validation; risk of cross-reactivity with plasminogen or other serum proteins; failure to consider potential problems when measuring samples with varying length of the Lp(a) polypeptide chain (i.e. failure to cope with the isoform variation); non-divulgence of contents of test reagents; and pretreatments of samples that drastically change the Lp(a) lipoprotein particles from their native state. Any test system should be validated at the scientific level before it is assumed to provide correct measurements of Lp(a) lipoprotein level in serum. New test kits should be safely anchored in validation in one of the research laboratories active in the area, before they are put on the market. As new batches are produced, the quality of every new batch of test kits should be monitored on a long-term basis in collaboration with a research laboratory.

Confounding Factors, Epidemiologic↗

PubMed1996

Gender, type of treatment, dysfunctional attitudes, social support, life events, and depressive symptoms over naturalistic follow-up.

OBJECTIVE: The present study investigated gender differences in depressive symptoms during a naturalistic follow-up for outpatients with major depressive disorder in the National Institute of Mental Health Treatment of Depression Collaborative Research Program. Specifically, the study investigated whether gender interacted with type of treatment received, dysfunctional attitudes, life events, or social support to predict severity of depressive symptoms. In addition, aspects of these psychosocial factors (need for approval, interpersonal life events, and close friendships), hypothesized to be more salient for women, were examined to determine if they had a differential impact on level of depressive symptoms in men and women. METHOD: Assessments conducted 6, 12, and 18 months after treatment included measures of depressive symptoms, dysfunctional attitudes, current life events, and social support. Data were available for 188 subjects (134 women and 54 men). Regression analyses were conducted to examine whether gender as a main effect, or interacting with dysfunctional attitudes, life events, social support, or subtypes of these variables, predicted cross-sectional or longitudinal measures of depressive symptoms during follow-up. RESULTS: A consistent finding of the study was that over the 18 months of this naturalistic follow-up, there were no main effects for gender or any significant interactions involving gender and any of the variables of interest. The study demonstrated that life events and social support were related to severity of depressive symptoms for both genders. CONCLUSIONS: Despite differential prevalence rates of major depression for men and women, findings do not support a different process in outcome of illness for men and women.

Adult↗

PubMedDate not supplied

Computer aided test selection (CATS) for nuclear medicine--a prototype system for renal investigations.

An expert system for renal test selection in nuclear medicine has been developed as the first stage of a collaborative project on test selection in nuclear medicine. The stages of knowledge elicitation and knowledge representation were addressed by means of a questionnaire which was completed by five experts in the field of renal nuclear medicine. A flow chart was developed from the responses and implemented using a commercially available expert system shell (Crystal 4.5). A menu specifying clinical problems, for which renal nuclear medicine is useful, is displayed to the user who is prompted for a choice. Specific aspects of the chosen problem are then shown and again a choice is requested. Selected tests, in order of expert preference, are displayed and further information on any of these is available, if required, on selection from a menu subdivided into categories such as patient preparation, preliminary investigations, etc. The system provides cross-referencing to other areas of investigation and is currently being evaluated using a structured approach commonly employed in the assessment of user interfaces.

Decision Making, Computer-Assisted↗

PubMed1996

Clinical detection of lung cancer progression markers.

Lung cancer is the leading cause of cancer-related deaths in western countries. The prognosis for patients with lung cancer depends primarily on the stage of the tumor at the time of clinical diagnosis. New understanding of tumor biology has turned attention away from detection of clinical lung cancer, usually metastatic at presentation, toward recognition of genetic and protein markers which precede malignancy. Mutations of four types of genes contribute to the process of epithelial carcinogenesis by modifying control of cell growth. Examples of three of these changes have been detected in pre-malignant sputum, and validated in subsequent tumor. We have identified gene products (tumor associated and differentiation protein antigens), mutations of k-ras and p53, and microsatellite alterations as potential markers of subsequent malignancy. We consider the morphologic progression seen in archived sputum cells as the paradigm of neoplastic development in the lung. Although the NCl collaborative trials had shown that this progression is not recognized sufficiently often (sensitive) to be useful for lung cancer screening, this progression may be used to assess the timing of gene and peptide markers of carcinogenesis. Previous work has shown that at the time Johns Hopkins Lung Project sputum cells express moderately atypical metaplasia, 53% (8/15) of sputum specimens expressed common (codon 12) k-ras or (codons 273 or 281) p53 mutations. Other investigators have reported that earlier morphologic changes (metaplasia) accompany 3p and 9p losses of heterozygosity. These observations suggest that 3p and 9p loss likely precede k-ras or p53 mutations. Our preliminary data demonstrate that over-expression of a 31 kD tumor associated antigen recently purified, sequenced, and identified as heterogeneous nuclear ribonucleoprotein (hnRNP) A2 (with cross reactivity to splice variant B1), is expressed in most lung cancer cases before any morphologic abnormality. Comparison of the accuracy of this marker with sputum cytology will determine its value for early lung cancer detection. Preliminary evidence confirms this marker greatly improves the accuracy of standard sputum cytology for detection of lung carcinogenesis. Clinical intervention trials must be undertaken to determine whether modulation of hnRNP overexpression is useful as an intermediate endpoint for chemoprevention.

Animals↗

PubMed2004

A cross-talk between hypoxia and TGF-beta orchestrates erythropoietin gene regulation through SP1 and Smads.

Erythropoietin (Epo) is the humoral regulator of red blood-cell production. Low oxygen tension increases the Epo levels by enhancing transcription, through the hypoxia-inducible factor (HIF)-1, a transcriptional modulator in oxygen-regulated gene expression. In the present work, a cooperative interaction between hypoxia, mediated by the HIF-1 complex, and transforming growth factor-beta (TGF-beta), mediated by Smad3/4, was revealed in the Epo gene. This cooperation is due to physical interaction between Smad3/4 and HIF-1alpha. The Smad3/4 binding site is located within the 3' Epo enhancer, downstream from the HRE consensus, and immediately adjacent to the orphan hepatic nuclear factor receptor (HNF-4). HNF-4 is interacting also with Smad3 and the HIF-1 complex, to potentiate further the cooperative effect between both factors. Moreover, Sp1 has been identified as the factor binding the promoter necessary for the full hypoxia inducibility of the EPO gene. However, this full induction is achieved only if the TGF-beta pathway is mediating a cross-talk between promoter (Sp1) and enhancer (HIF-1alpha) regions through Smad3. We show that Sp1 binding to the proximal promoter is relevant for Epo transcription, and contributes to the Epo induction by hypoxia. A functional cooperation among the transcription factors mediating hypoxia (HIF-1, Sp1), the TGF-beta pathway (Smad3/4), and tissue-specific HNF-4 is proposed for the regulation of the Epo gene. In this model, the physical contact between the upstream promoter and the 3' downstream enhancer is mediated by Sp1 and Smad3 factors, and would occur upon bending of the DNA intervening sequences. Thus, Sp1 would reinforce the promoter/enhancer contact, while Smad3 would stabilize the multifactorial complex by interacting with HIF-1/Sp1/HNF-4 and the coactivator CBP/p300. This model may be extended to other genes where collaboration between TGF-beta and hypoxia takes place.

Animals↗

PubMed2005

Monte Carlo modeling of gamma cameras for I-131 imaging in targeted radiotherapy.

INTRODUCTION: Dosimetric studies for targeted radiotherapy require the quantification of activity from scintigraphic images. Quantitative imaging is difficult to achieve because of several effects that can lead to errors in activity estimates, some of which are more apparent when I-131 is considered as a source. An evaluation of these phenomena was performed by modeling the gamma camera and its behavior using Monte Carlo simulations. Two gamma cameras were modeled: DST-XLi and Millennium VG Hawk-Eye (GEMS), and two Monte Carlo codes were used: MCNP (LANL) and GATE (openGate collaboration). GATE is a dedicated single photon emission computed tomography/positron emission tomography (SPECT)/(PET) software based on Geant4 (CERN, Geneve). MATERIALS AND METHODS: Gamma-camera modeling was performed in 2 steps: first without a collimator, then with a high-energy, all-purpose (HEAP) collimator according to the specifications given by the manufacturer (the simulation took the hexagonal shape of collimator holes into account). Simulated and measured energy spectra from point sources in air were compared (with or without a collimator). Spatial resolution was obtained from line sources in air at various distances from the detector heads. The photons detected in the 20% energy window from a point source were analyzed in order to determine the amount of primary photons, scattered photons (in the collimator), and septal photons (i.e., photons that crossed the collimator septa without interacting). RESULTS: Both codes agree well with experimental measurements for the two gamma cameras considered in this study. This allowed us to validate gamma-camera modeling and also served as a benchmark of GATE (new code) versus MCNP (reference code). As shown previously by Dewaraja et al., septal penetration is an important source of image degradation when HEAP collimators are used for I-131 imaging. With the DST-XLi, and for a point source in air, our simulations have shown that 53% of scattered (30%) and septal penetration (23%) photons are detected in the 20% window. CONCLUSION: The modeling of two gamma cameras (DST-XLi and Millennium VG Hawk-Eye) has been performed with two Monte Carlo codes (MCNP and Gate). Results obtained with the two Monte Carlo codes agree well with experimental results. As already indicated by several authors, septal penetration and scattered photons in the collimator have a major impact on I-131 scintigraphic imaging.

Computer Simulation↗

PubMed2002

Achievement of insulin independence in three consecutive type-1 diabetic patients via pancreatic islet transplantation using islets isolated at a remote islet isolation center.

BACKGROUND: As a result of advances in both immunosuppressive protocols and pancreatic islet isolation techniques, insulin independence has recently been achieved in several patients with type 1 diabetes mellitus via pancreatic islet transplantation (PIT). Although the dissemination of immunosuppressive protocols is quite easy, transferring the knowledge and expertise required to isolate a large number of quality human islets for transplantation is a far greater challenge. Therefore, in an attempt to centralize the critical islet processing needed for islet transplantation and to avoid the development of another islet processing center, we have established a collaborative islet transplant program between two geographically distant transplant centers. PATIENTS AND METHODS: Three consecutive patients with type 1 diabetes mellitus with a history of severe hypoglycemia and metabolic instability underwent PIT at the Methodist Hospital (TMH), Houston, Texas, using pancreatic islets. All pancreatic islets were isolated from pancreata procured in Houston and subsequently transported for isolation to the Human Islet Cell Processing Facility of the Diabetes Research Institute (DRI) at the University of Miami, Miami, Florida. Pancreatic islets were isolated at DRI after enzymatic ductal perfusion (Liberase-HI) by the automated method (Ricordi Chamber) using endotoxin-free and xenoprotein-free media. After purification, the islets were immediately transported back to TMH and transplanted via percutaneous transhepatic portal embolization. Immunosuppression consisted of sirolimus, tacrolimus, and daclizumab. RESULTS: After donor cross-clamp in Houston, donor pancreata arrived at DRI and the isolation process began within 6.5 hr in all cases (median, 5.4 hr; range, 4.8-6.5 hr). At the completion of the isolation process, the islets were immediately transported back to TMH and transplanted. All three patients attained sustained insulin independence after transplantation of 395,567, 394,381, and 563,206 pancreatic islet equivalents (IEQ), respectively. Despite insulin independence, the first two patients received less than 10,000 IEQ/kg; therefore, to increase their functional pancreatic islet reserve, they underwent a second islet transplant with 326,720 and 768,132 IEQ, respectively. Posttransplantation follow-up for these three patients is 4, 3, and 0.5 months, respectively. The mean glycosylated hemoglobin values have been dramatically reduced in the first two patients. In addition, the mean amplitude of glycemic excursions have also been reduced in all three recipients (patient 1: before transplantation 197 mg/dL vs. after transplantation 61 mg/dL; patient 2: before transplantation 202 mg/dL vs. after transplantation 52 mg/dL; patient 3: before transplantation 245 mg/dL vs. after transplantation 58 mg/dL) after PIT. All pancreatic islet allografts demonstrated the ability to respond to an in vitro glucose stimulus at the DRI before shipment and at TMH after shipment and final processing with a median stimulation index of 2.1 and 2.2, respectively. None of the transplant recipients have had a hyper- or hypoglycemic episode since PIT and no complications have occurred. CONCLUSIONS: These early data demonstrate that (1) pancreatic islets remain viable after shipment to remote transplant sites; (2) pancreatic islet isolation techniques and experience can be concentrated at a small number of regional facilities that could supply islets to remote transplant centers; and (3) insulin independence via PIT can be achieved using a remote pancreatic islet isolation center.

Adolescent↗

PubMed1988

Dust mite allergens and asthma: a worldwide problem. International Workshop report.

After the discovery of house dust mites in 1964 their association with asthma has been reported from many different parts of the world including the developing countries. Two sets of major allergens from mites of the genus Dermatophagoides are now well recognized. The Group I allergens are glycoproteins of relative molecular mass (M(r)) 25 000, which show both structural homology and cross-reactivity. The allergen Der p I has been cloned and sequenced confirming the M(r) and establishing its nature as a protease. The Group II allergens (M(r) 15 000) show even closer homology and cross-reactivity. Specific immunoassays for Group I and Group II allergens, using monospecific antisera and monoclonal antibodies, have been standardized and are suitable for measuring allergen levels in different parts of the world.Measures for reducing the levels of mite allergens in houses include the covering of mattresses, hot washing of bedding, and removal of carpets from bedrooms as well as humidity control, vacuum cleaning, and the use of acaricides in the rest of the house. There is already evidence that these procedures can cause a major improvement in the symptoms of asthma. While provisional standards for both sensitization to mites and also mite allergen exposure can now be recommended, there is an urgent need for controlled studies using protocols demonstrated to reduce mite allergen levels by at least tenfold and for further international collaboration.

Allergens↗

PubMed1995

New directions in dietary studies and heart disease: the National Heart, Lung and Blood Institute sponsored Multicenter Study of Diet Effects on Lipoproteins and Thrombogenic Activity.

The National Heart, Blood and Lung Institute-sponsored DELTA study is the first collaborative, multicenter diet study to utilize standardized protocols to feed specific diets to study participants. In the first study, the investigators are focusing on the effects of reducing dietary saturated fat on plasma lipids, lipoproteins, and thrombogenic activity. Future studies will attempt to address important diet/public health questions dealing with high carbohydrate vs. high monounsaturated fat diets, and the cholesterol raising activity of specific saturated fatty acids. Moreover, DELTA will be an invaluable model for other multicenter diet studies.

Adult↗

PubMedDate not supplied

The new program of the World Health Organization in medical virology.

The World Health Organization (WHO) convened a Scientific Group to adapt its program in virus diseases to recent progress in virology. The program consists of (a) general activities, such as reference services and the supplying of reagents by the WHO Collaborating Centres and (b) specific activities to solve problems-including the promotion of necessary research-caused by certain diseases of public health importance. The Group reviewed problems caused by influenza and other respiratory viruses, enteroviruses, gastroenteritis viruses (for which types A and B have been proposed as a convenient nomenclature), viral hepatitis, viruses in water and sewage, arboviruses, arenaviruses and Marburg virus, measles and rubella vaccination, smallpox, rabies, chronic infections, herpesviruses, oncogenic viruses, congenital infections, nosocomial infections, chlamydial and rickettsial infections, and mycoplasma infections.

Arboviruses↗

PubMed2006

Issues in practice based learning in nursing in the United Kingdom and the Republic of Ireland: Results from a multi professional scoping exercise.

The first year (2003-2004) of a three year nationally funded project focused on completing a scoping exercise on the nature of practice education in five selected health care professions: Dietetics, Nursing, Occupational Therapy, Physiotherapy and Radiography (). A survey questionnaire, focus groups and secondary sources were used to collect data. Profession specific contributors completed the analysis of results. Resulting case studies were combined to produce a cross-professional overview of current issues in practice-based learning. The nursing case study identified areas of good practice such as; the mentorship model; the development of new support roles; and joint responsibility between Higher Education Institutes (HEIs) and Health Service areas for practice assessment. However, there were variations in the application of these areas of good practice throughout the United Kingdom (UK). Issues included; an inadequate supply of qualified mentors; formal recognition of the mentor role; and lack of knowledge of the relative impact of the differing mentor preparation programmes. In comparing the five professions, all had statutory requirements regarding the nature of practice learning but each profession differed in how this was managed and organised. The need for formal preparation, recognition and reward for the mentor/practice educator role was recognised with collaborative working across the professions a recommendation in order to achieve national improvement in the quality of practice learning support for health care professions.

Attitude of Health Personnel↗

PubMed2004

Culturally responsive care for Hmong patients. Collaboration is a key treatment component.

Since the end of the Vietnam War, tens of thousands of Hmong refugees have resettled in the United States. This ever-increasing population presents specific challenges to the US healthcare system as Hmong seek to preserve their cultural identity while acclimating to American society. Primary care physicians can enhance their interactions with these patients by seeking to understand various elements of Hmong culture, particularly its approach to medicine and healing. By extension, such knowledge and skills will aid physicians in all encounters with patients who belong to minority cultural groups.

Asian↗

PubMed1991

Relative frequencies of secondary B cells activated by cognate vs. other mechanisms.

Three distinct mechanisms for the activation of secondary B cells to antibody-forming cells have been examined in splenic fragment cultures. The clonal response to a protein antigen [cytochrome c (cyt)] was quantified in terms of both the number of B cells activated and the amount of antibody produced by each clone. The vast majority of memory B cells required surface immunoglobulin (sIg) receptor-mediated uptake of antigen followed by cognate interactions with an antigen-specific T helper cell. Nevertheless, a significant number (as many as 12%) could be activated via soluble factor-mediated bystander activation, involving occupation of neither the sIg receptor nor class II major histocompatibility complex (MHC) molecules. This pathway, however, was relatively inefficient in that individual clones secreted less than half as much antibody as clones activated as a result of cognate collaboration with a T helper cell. A similar number of secondary B cells were activated following nonspecific uptake of high concentrations of antigen for which splenic fragment T cells had been primed [i.e., hemocyanin (Hy)], independent of sIg receptor occupancy. Antibody levels were similar to those in cultures where B cells were activated in a cognate manner with sIg receptor occupancy. When Hy-stimulated fragment cultures were supplemented with polymerized cyt, the frequency of activation via this latter pathway increased fourfold, despite the fact that no cyt-primed T cells were present. This observation supports the idea that receptor-mediated uptake of antigen serves not just to focus antigen but also provides an important signal in activating B cells. Bystander B cell activation, however, was not enhanced by providing a sIg cross-linking signal with polymerized cyt. The lower level of antibody production by B cells activated in a bystander fashion and the inability to enhance their frequency of activation with sIg receptor occupancy suggest that there is indeed a fundamental difference between soluble factor-mediated bystander activation and activation via T cell determinant-mediated cognate T helper-B cell interactions, perhaps involving signaling through class II MHC molecules.

Animals↗

PubMed1990

Progress towards boron neutron capture therapy at the High Flux Reactor Petten.

During 1988 the first positive steps were taken to proceed with the design and construction of a neutron capture therapy facility on the High Flux Reactor (HFR) at Petten. The immediate aim is to realise within a short time (summer 1989), an epithermal neutron beam for radiobiological and filter optimisation studies on one of the 10 small aperture horizontal beam tubes. The following summer, a much larger neutron beam, i.e., in cross section and neutron fluence rate, will be constructed on one of the two large beam tubes that replaced the old thermal column in 1984. This latter beam tube faces one whole side of the reactor vessel, extending from a 50 x 40 cm input aperture to a 35 x 35 cm exit hole. The radiotherapeutic facility will be housed here, with the intention to start clinical trials at the beginning of 1991. This paper describes the present status of the project and includes: a general description of the pertinent characteristics with respect to NCT of the HFR; results of the recently completed preliminary neutron metrology and computer modeling at the input end of the candidate beam tube; the structure and planning of the proposed Work Programme; and the respective direct and indirect participation and collaboration with the Netherlands Cancer Institute and the European Collaboration Group on BNCT.

Animals↗

PubMed1993

International collaboration comparing neutralization and binding assays for monoclonal antibodies to simian immunodeficiency virus.

Thirteen laboratories characterized a coded panel of 10 MAbs to SIVmac251 envelope protein in a collaboration organized by the National Institute of Allergy and Infectious Diseases (NIAID). The MAbs were examined against SIV isolates in neutralization and radioimmune precipitation, immunoblot, enzyme-linked immunosorbent, and radioimmune assays. Although laboratories employed diverse neutralization assays that varied in sensitivity there was agreement on the relative ability of the MAbs to neutralize SIVmac251. Additionally, even though the quantity of any single MAb required to neutralize SIVmac251 varied between laboratories, there was agreement on the rank-order strength fo the five neutralizing MAbs. Based on the data from this study, the MAbs were classified according to their neutralization potential as high efficiency (MAb concentration, < 5 micrograms/ml), low efficiency (MAb concentration, 5-100 micrograms/ml), or nonneutralizing (MAb concentration, > 100 micrograms/ml). The MAbs could be assigned to four serological groups based on ability to cross-neutralize and bind different SIV isolates. The distinction between groups I, II, and III were based on the limited neutralization data obtained with the sooty mangabey isolate.

Animals↗

PubMed2004

Strategies for engaging the private sector in sexual and reproductive health: how effective are they?

The private health sector provides a significant portion of sexual and reproductive health (SRH) services in developing countries. Yet little is known about which strategies for intervening with private providers can improve quality or coverage of services. We conducted a systematic review of the literature through PubMed from 1980 to 2003 to assess the effectiveness of private sector strategies for SRH services in developing countries. The strategies examined were regulating, contracting, financing, franchising, social marketing, training and collaborating. Over 700 studies were examined, though most were descriptive papers, with only 71 meeting our inclusion criteria of having a private sector strategy for one or more SRH services and the measurement of an outcome in the provider or the beneficiary. Nearly all studies (96%) had at least one positive association between SRH and the private sector strategy. About three-quarters of the studies involved training private providers, though combinations of strategies tended to give better results. Maternity services were most commonly addressed (55% of studies), followed by prevention and treatment of sexually transmitted diseases (32%). Using study design to rate the strength of evidence, we found that the evidence about effectiveness of private sector strategies on SRH services is weak. Most studies did not use comparison groups, or they relied on cross-sectional designs. Nearly all studies examined short-term effects, largely measuring changes in providers rather than changes in health status or other effects on beneficiaries. Five studies with more robust designs (randomized controlled trials) demonstrated that contraceptive use could be increased through supporting private providers, and showed cases where the knowledge and practices of private providers could be improved through training, regulation and incentives. Although tools to work with the private sector offer considerable promise, without stronger research designs, key questions regarding their feasibility and impact remain unanswered.

Delivery of Health Care↗

PubMed1997

Recruitment, retention and characteristics of women in a prospective study of preconceptional risks to reproductive outcomes: experience of the Diana Project.

Preterm delivery, low birthweight, and intrauterine growth retardation are common and recalcitrant problems in many countries. Although much remains to be learned, we know particularly little about the relationships between preconceptional and early pregnancy exposures and these and other reproductive outcomes. The study presented here was primarily designed to investigate the relationships between nutritional exposures measured before and during pregnancy and reproductive outcomes. This paper describes methods used to recruit the required 1000 preconceptional women from the collaborating health maintenance organisation (HMO) and the retention of participants in this time-intensive study. The results presented demonstrate that an adequate completion rate (66.3%), and a remarkably representative sample of women that poses few threats to the study's validity, can be obtained by population-based recruitment of women from an HMO.

Adult↗