Detecting national human enteric disease outbreaks linked to animal contact in the United States of America.

Enteric pathogens, such as non-typhoidal Salmonella, Campylobacter and Escherichia coli, can reside in the intestinal tract of many animals, including livestock, companion animals, small mammals and reptiles. Often, these animals can appear healthy; nonetheless, humans can become infected after direct or indirect contact, resulting in a substantial illness burden. An estimated 14% of the 3.2 million illnesses that occur in the United States of America (USA) each year from such enteric pathogens are attributable to animal contact. Surveillance for enteric pathogens in the USA includes the compilation and interpretation of both laboratory and epidemiologic data. However, the authors feel that a collaborative, multisectoral and transdisciplinary - or One Health - approach is needed for data collection and analysis, at every level. In addition, they suggest that the future of enteric illness surveillance lies in the development of improved technologies for pathogen detection and characterisation, such as genomic sequencing and metagenomics. In particular, using whole-genome sequencing to compare genetic sequences of enteric pathogens from humans, food, animals and the environment, can help to predict antimicrobial resistance among these pathogens, determine their genetic relatedness and identify outbreaks linked to a common source. In this paper, the authors describe three recent, multi-state human enteric illness outbreaks linked to animal contact in the USA and discuss how integrated disease surveillance was essential to outbreak detection and response. Additional datasharing between public health and animal health laboratories and epidemiologists at the local, national, regional and international level may help to improve surveillance for emerging animal and human health threats and lead to new opportunities for prevention.

Les agents pathogènes entériques tels que les Salmonella non typhiques, Campylobacter et Escherichia coli peuvent coloniser le tractus intestinal d'un grand nombre d'animaux y compris les espèces d'élevage, les animaux de compagnie, les petits mammifères et les reptiles. Les animaux porteurs sont souvent sains en apparence ; néanmoins, les humains peuvent contracter l'infection après un contact direct ou indirect avec un animal atteint, ce qui induit un fardeau significatif associé à ces maladies. D'après les estimations, environ 14 % des 3,2 millions de cas annuels d'infections par des agents pathogènes entériques aux États-Unis d'Amérique ont pour origine un contact avec des animaux. Aux États-Unis, la surveillance des agents pathogènes entériques est basée sur la collecte et l'interprétation des résultats de laboratoire et des données épidémiologiques. Les auteurs sont néanmoins convaincus de la nécessité de recourir à une approche collaborative, multisectorielle et transdisciplinaire (en d'autres termes, une approche Une seule santé) pour la collecte et l'analyse des données, à tous les niveaux. Ils considèrent également que la surveillance des infections entériques reposera à l'avenir sur le développement de technologies avancées dans le domaine de la détection et de la caractérisation des agents pathogènes, notamment le séquençage génomique et la métagénomique. En particulier, le recours au séquençage du génome entier afin de comparer les séquences d'agents pathogènes d'origine humaine, alimentaire, animale et environnementale permettra d'anticiper l'apparition d'antibiorésistances, de déterminer le degré de parenté génétique de ces agents et d'identifier les foyers provenant d'une même source. Les auteurs décrivent trois foyers récents d'infections entériques humaines survenus dans plusieurs états des États-Unis et soulignent à quel point l'exercice d'une surveillance sanitaire intégrée a été déterminant pour la détection de ces foyers et la mise en œuvre d'une réponse appropriée. Un partage accru d'informations entre les laboratoires et les épidémiologistes de santé publique et animale aux niveaux local, national, régional et international pourrait contribuer à améliorer la surveillance des menaces émergentes pesant sur la santé animale et humaine et à mettre en œuvre de nouvelles modalités de prévention.

En el tracto intestinal de muchos animales, entre ellos ganado, mascotas, pequeños mamíferos o reptiles, puede haber patógenos intestinales como salmonelas no tifoideas, Campylobacter o Escherichia coli. A menudo los animales parecen sanos, pese a lo cual las personas pueden infectarse por contacto directo o indirecto con ellos, lo que da lugar a una considerable carga de morbilidad. Se calcula que, de los 3,2 millones de casos de enfermedad que estos patógenos intestinales causan al año en los EE. UU., un 14% es atribuible al contacto con animales. La vigilancia de patógenos intestinales que se practica en los EE. UU. incluye la compilación e interpretación de datos tanto epidemiológicos como de laboratorio. En opinión de los autores, sin embargo, es preciso que la obtención y el análisis de datos respondan a un planteamiento de colaboración multisectorial y transdisciplinar ­ esto es, a la lógica de Una sola salud ­ que abarque todos los niveles. Los autores apuntan además que el futuro de la vigilancia de las enfermedades intestinales pasa por el desarrollo de tecnologías más eficaces de detección y caracterización de patógenos, como la secuenciación genómica o la metagenómica. En particular, el uso de la secuenciación de genomas completos para comparar entre sí las secuencias genéticas de patógenos intestinales presentes en personas, alimentos, animales y el medio ambiente puede ayudar a predecir la aparición de resistencias a los antimicrobianos en estos patógenos, determinar su parentesco genético e identificar brotes vinculados con un origen común. Los autores, tras describir tres recientes brotes de enfermedad intestinal humana ligados al contacto con animales que afectaron a varios estados de los EE. UU., explican la función esencial que cumplió la vigilancia integrada de enfermedades para detectar esos brotes y responder a ellos. El intercambio de más datos entre los laboratorios de salud pública y sanidad animal y los epidemiólogos a escala local, nacional, regional e internacional puede ser de ayuda para mejorar la vigilancia de amenazas sanitarias y zoosanitarias emergentes y abrir nuevas posibilidades de prevención.

Development of a battery of tests to measure attitudes and intended behaviours of dental students towards people with disability or those in marginalised groups.

INTRODUCTION: Recommended curricula in Special Care Dentistry (SCD) outline learning objectives that include the domain of attitudes and behaviours, but these are notoriously difficult to measure. The aims of this study were (i) to develop a test battery comprising adapted and new scales to evaluate values, attitudes and intentions of dental students towards people with disability and people in marginalised groups and (ii) to determine reliability (interitem consistency) and validity of the scales within the test battery. MATERIALS AND METHODS: A literature search identified pre-existing measures and models for the assessment of attitudes in healthcare students. Adaptation of three pre-existing scales was undertaken, and a new scale was developed based upon the Theory of Planned Behaviour (TPB) using an elicitation survey. These scales underwent a process of content validation. The three adapted scales and the TPB scale were piloted by 130 students at 5 different professional stages, from 4 different countries. RESULTS: The scales were adjusted to ensure good internal reliability, variance, distribution, and face and content validity. In addition, the different scales showed good divergent validity. DISCUSSION: These results are positive, and the scales now need to be validated in the field. CONCLUSIONS: It is hoped that these tools will be useful to educators in SCD to evaluate the impact of teaching and clinical exposure on their students.

Assessing the influence of secondary organic versus primary carbonaceous aerosols on long-range atmospheric polycyclic aromatic hydrocarbon transport.

We use the chemical transport model GEOS-Chem to evaluate the hypothesis that atmospheric polycyclic aromatic hydrocarbons (PAHs) are trapped in secondary organic aerosol (SOA) as it forms. We test the ability of three different partitioning configurations within the model to reproduce observed total concentrations in the midlatitudes and the Arctic as well as midlatitude gas-particle phase distributions. The configurations tested are (1) the GEOS-Chem default configuration, which uses instantaneous equilibrium partitioning to divide PAHs among the gas phase, a primary organic matter (OM) phase (absorptive), and a black carbon (BC) phase (adsorptive), (2) an SOA configuration in which PAHs are trapped in SOA when emitted and slowly evaporate from SOA thereafter, and (3) a configuration in which PAHs are trapped in primary OM/BC upon emission and subsequently slowly evaporate. We also test the influence of changing the fraction of PAHs available for particle-phase oxidation. Trapping PAHs in SOA particles upon formation and protecting against particle-phase oxidation (2) better simulates observed remote concentrations compared to our default configuration (1). However, simulating adsorptive partitioning to BC is required to reproduce the magnitude and seasonal pattern of gas-particle phase distributions. Thus, the last configuration (3) results in the best agreement between observed and simulated concentration/phase distribution data. The importance of BC rather than SOA to PAH transport is consistent with strong observational evidence that PAHs and BC are coemitted.

Ichthyophonus-infected walleye pollock Theragra chalcogramma (Pallas) in the eastern Bering Sea: a potential reservoir of infections in the North Pacific.

In 2003, the Alaska walleye pollock industry reported product quality issues attributed to an unspecified parasite in fish muscle. Using molecular and histological methods, we identified the parasite in Bering Sea pollock as Ichthyophonus. Infected pollock were identified throughout the study area, and prevalence was greater in adults than in juveniles. This study not only provides the first documented report of Ichthyophonus in any fish species captured in the Bering Sea, but also reveals that the parasite has been present in this region for nearly 20 years and is not a recent introduction. Sequence analysis of 18S rDNA from Ichthyophonus in pollock revealed that consensus sequences were identical to published parasite sequences from Pacific herring and Yukon River Chinook salmon. Results from this study suggest potential for Ichthyophonus exposures from infected pollock via two trophic pathways; feeding on whole fish as prey and scavenging on industry-discharged offal. Considering the notable Ichthyophonus levels in pollock, the low host specificity of the parasite and the role of this host as a central prey item in the Bering Sea, pollock likely serve as a key Ichthyophonus reservoir for other susceptible hosts in the North Pacific.

Inability to demonstrate fish-to-fish transmission of Ichthyophonus from laboratory infected Pacific herring Clupea pallasii to naïve conspecifics.

The parasite Ichthyophonus is enzootic in many marine fish populations of the northern Atlantic and Pacific Oceans. Forage fishes are a likely source of infection for higher trophic level predators; however, the processes that maintain Ichthyophonus in forage fish populations (primarily clupeids) are not well understood. Lack of an identified intermediate host has led to the convenient hypothesis that the parasite can be maintained within populations of schooling fishes by waterborne fish-to-fish transmission. To test this hypothesis we established Ichthyophonus infections in Age-1 and young-of-the-year (YOY) Pacific herring Clupea pallasii (Valenciennes) via intraperitoneal (IP) injection and cohabitated these donors with naïve conspecifics (sentinels) in the laboratory. IP injections established infection in 75 to 84% of donor herring, and this exposure led to clinical disease and mortality in the YOY cohort. However, after cohabitation for 113 d no infections were detected in naïve sentinels. These data do not preclude the possibility of fish-to-fish transmission, but they do suggest that other transmission processes are necessary to maintain Ichthyophonus in wild Pacific herring populations.

von Willebrand factor/factor VIII concentrate (Humate-P) for management of elective surgery in adults and children with von Willebrand disease.

von Willebrand disease (VWD) is the most common inherited bleeding disorder. Treatment guidelines recommend the use of von Willebrand factor/factor VIII (VWF/FVIII) concentrate for VWD patients with type 2 or 3 VWD undergoing surgery, and type 1 patients undergoing surgery who are unresponsive, or for whom desmopressin acetate is contraindicated. This prospective, open-label, multinational study evaluated the safety, efficacy and optimal dosing of a VWF/FVIII concentrate (Humate-P) in subjects with VWD undergoing elective surgery. Dosing was based on VWF ristocetin cofactor (VWF:RCo) and FVIII pharmacokinetic assessments performed before surgery. Pharmacokinetic assessments were completed in 33 adults and 9 children. Haemostatic efficacy was assessed on a 4-point scale (excellent, good, moderate/poor or none). Overall effective haemostasis was achieved in 32/35 subjects. Median terminal VWF:RCo half-life was 11.7 h, and median incremental in vivo recovery was 2.4 IU dL(-1) per IU kg(-1) infused. Major haemorrhage occurred after surgery in 3/35 cases despite achieving target VWF and FVIII levels. Median VWF/FVIII concentrate loading doses ranged from 42.6 IU VWF:RCo kg(-1) (oral surgery) to 61.2 IU VWF:RCo kg(-1) (major surgery), with a median of 10 (range, 2-55) doses administered per subject. Adverse events considered possibly treatment-related (n = 6) were generally mild and of short duration. The results indicate that this VWF/FVIII concentrate is safe and effective in the prevention of excessive bleeding during and after surgery in individuals with VWD.

Toward an Information Infrastructure for Global Health Improvement.

Profound global challenges to individual and population health, alongside the opportunities to benefit from digital technology, have spawned the concept of the Learning Health System. Learning Health Systems (LHSs)--which can function at organizational, network, regional, and national levels of scale--have the capability of continuous data-driven self-study that promotes change and improvement. The LHS concept, which originated in the U.S. in 2007, is rapidly gaining attention around the world. LHSs require, but also transcend, the secondary use of health data. This paper describes the key features of LHSs, argues that effective and sustainable LHSs must be supported by infrastructures that allow them to function with economies of scale and scope, and describes the services that such infrastructures must provide. While it is relatively straightforward to describe LHSs, achieving them at the high level of capability necessary to promote significant health benefits will require advancements in science and engineering, engaging the field of informatics among a wider range of disciplines. It also follows from this vision that LHSs cannot be built from an imposed blueprint; LHSs will more likely evolve from efforts at smaller scales that compose into larger systems.

Patient-Centered Network of Learning Health Systems: Developing a resource for clinical translational research.

INTRODUCTION: The Learning Health System Network clinical data research network includes academic medical centers, health-care systems, public health departments, and health plans, and is designed to facilitate outcomes research, pragmatic trials, comparative effectiveness research, and evaluation of population health interventions. METHODS: The Learning Health System Network is 1 of 13 clinical data research networks assembled to create, in partnership with 20 patient-powered research networks, a National Patient-Centered Clinical Research Network. RESULTS AND CONCLUSIONS: Herein, we describe the Learning Health System Network as an emerging resource for translational research, providing details on the governance and organizational structure of the network, the key milestones of the current funding period, and challenges and opportunities for collaborative science leveraging the network.

Intercalative binding of ellipticine to DNA.

Ellipticine (NSC 71795), a plant alkaloid with antitumor activity, is a weakly basic polycyclic molecule with dimensions similar to those of proflavin. Like proflavin, ellipticine exhibits hypocromic and bathochromic changes in absorption spectrum in the presence of DNA. It binds preferentially to helical DNA by intercalation, but the strength of binding is substantially greater than that of proflavin. The evidence for intercalation is based on effects on the sedimentation and viscosity of sheared DNA fragments, removal and reversal of the supercoiling of closed circular DNA, and electric dichroism measurements. The sedimentation and viscosity changes are quantitatively similar to those produced by proflavin. The unwinding angle on binding to supercoiled DNA is estimated to be 7.9 degrees, similar to that of proflavin. Electric dichroism shows the plane of the bound ellipticine molecule to be oriented parallel (plus or minus 7 degrees) to the plane of the bases in helical DNA. Ellipticine differs from proflavin in that it is uncharged at neutral pH and becomes protonated under mildly acid conditions. This feature may influence the intracellular distribution of the drug. Ellipticine bound to DNA is probably in its protonated form.

Assignment of the human p27Kip1 gene to 12p13 and its analysis in leukemias.

The p27Kip1 (p27) gene encodes an inducible inhibitor of cyclin-dependent kinase activity. Using a murine p27 cDNA as probe, we obtained a human cDNA clone and subsequently used it to isolate a genomic clone of this gene. The coding region of the human p27 gene was contained in two exons. Both the amino acid sequence and intron-exon organization of p27 were similar to those previously found for the related cyclin-dependent kinase inhibitor p21Waf1 (p21). The p27 gene was localized to chromosome band 12p13 by a combination of somatic cell hybrid and fluorescence in situ hybridization analyses. The p27 gene product is thought to control the leukocyte cell cycle and the 12p13 chromosomal band is known to be deleted in leukemias, suggesting that the p27 gene may act as a tumor suppressor gene in leukemias. Although p27 was found to reside in the minimal region of chromosomal loss in hematological malignancies, no mutations of p27 were observed in leukemia samples. Haploinsufficiency of p27 may confer a growth advantage to leukemia cells.

PART-1: a novel human prostate-specific, androgen-regulated gene that maps to chromosome 5q12.

Genes regulated by androgenic hormones are of critical importance for the normal physiological function of the human prostate gland, and they contribute to the development and progression of prostate carcinoma. We used cDNA microarrays containing 1500 prostate-derived cDNAs to profile transcripts regulated by androgens in prostate cancer cells. This study identified a novel gene that we have designated PART-1 (prostate androgen-regulated transcript 1), which exhibited increased expression upon exposure to androgens in the LNCaP prostate cancer cell line. Northern analysis demonstrated that PART-1 is highly expressed in the prostate gland relative to other normal human tissues and is expressed as different transcripts using at least three different polyadenylation signals. The PART-1 cDNA and putative protein are not significantly homologous to any sequences in the nonredundant public sequence databases. Cloning and analysis of the putative PART-1 promoter region identified a potential binding site for the homeobox gene PBX-la, but no consensus androgen response element or sterol-regulatory element binding sites were identified. We used a radiation hybrid panel and fluorescence in situ hybridization to map the PART-1 gene to chromosome 5q12, a region that has been suggested to harbor a prostate tumor suppressor gene. These results identify a new gene involved in the androgen receptor-regulated gene network of the human prostate that may play a role in the etiology of prostate carcinogenesis.

Randomized trial of supplemental beta-carotene to prevent second head and neck cancer.

Beta-carotene has established efficacy in animal models of oral carcinogenesis and has been shown to regress oral precancerous lesions in humans. The purpose of this study was to see whether these effects extended to the prevention of oral/pharyngeal/laryngeal (head and neck) cancer in humans. The subject population for this randomized, placebo-controlled, double-blinded clinical trial included 264 patients who had been curatively treated for a recent early-stage squamous cell carcinoma of the oral cavity, pharynx, or larynx. Patients were assigned randomly to receive 50 mg of beta-carotene per day or placebo and were followed for up to 90 months for the development of second primary tumors and local recurrences. After a median follow-up of 51 months, there was no difference between the two groups in the time to failure [second primary tumors plus local recurrences: relative risk (RR), 0.90; 95% confidence interval (CI), 0.56-1.45]. In site-specific analyses, supplemental beta-carotene had no significant effect on second head and neck cancer (RR, 0.69; 95% CI, 0.39-1.25) or lung cancer (RR, 1.44; 95% CI, 0.62-3.39). Total mortality was not significantly affected by this intervention (RR, 0.86; 95% CI, 0.52-1.42). Whereas none of the effects were statistically significant, the point estimates suggested a possible decrease in second head and neck cancer risk but a possible increase in lung cancer risk. These effects are consistent with the effects observed in trials using intermediate end point biological markers in humans, in which beta-carotene has established efficacy in oral precancerous lesions but has no effect or slightly worsens sputum cytology, and in animal carcinogenicity studies, in which beta-carotene has established efficacy in buccal pouch carcinogenesis in hamsters but not in animal models of respiratory tract/lung carcinogenesis, with some suggestions of tumor-promoting effects in respiratory tract/lung. If our results are replicated by other ongoing/completed trials, this suggests a critical need for mechanistic studies addressing differential responses in one epithelial site (head and neck) versus another (lung).

Comparative clinical trial of granisetron and ondansetron in the prophylaxis of cisplatin-induced emesis. The Granisetron Study Group.

PURPOSE: To compare the efficacy and safety of granisetron and ondansetron, serotonin (5-HT3) receptor antagonists shown to be effective in the prevention of chemotherapy-induced emesis. PATIENTS AND METHODS: In a double-blind, randomized, stratified, parallel-group study, the efficacy and safety of granisetron and ondansetron were compared in 987 chemotherapy-naive patients who received cisplatin in doses > or = 60 mg/m2. Granisetron was administered as a single dose of 10 or 40 micrograms/kg before the start of chemotherapy. Ondansetron was administered in doses of 0.15 mg/kg before and 4 and 8 hours after the start of chemotherapy. The three treatment groups were well-matched with respect to demographic characteristics and the dose of cisplatin administered. RESULTS: For all evaluations, single doses of granisetron 10 or 40 micrograms/kg were as effective as three 0.15-mg/kg doses of ondansetron. Total control (no vomiting, no retching, no nausea, and no use of rescue) was attained by 38%, 41%, and 39% of all patients who received granisetron 10 microgram/kg, granisetron 40 micrograms/kg, and ondansetron, respectively. No vomiting or retching and no use of rescue antiemetics were reported in 47%, 48%, and 51% of patients who received granisetron 10 micrograms/kg, granisetron 40 micrograms/kg, and ondansetron, respectively; no nausea and no use of rescue antiemetics were reported in 39%, 42%, and 40% of patients, respectively. CONCLUSION: All three treatment regimens were well-tolerated. The results of this study indicate that a single dose of granisetron 10 or 40 micrograms/kg is as effective as three doses of ondansetron 0.15 mg/kg in the prevention of nausea and vomiting induced by cisplatin chemotherapy.

Comparison of single-dose oral granisetron versus intravenous ondansetron in the prevention of nausea and vomiting induced by moderately emetogenic chemotherapy: a multicenter, double-blind, randomized parallel study.

PURPOSE: The antiemetic effectiveness and safety of single-dose oral granisetron were compared with intravenous (I.V.) ondansetron in chemotherapy-naive patients who received moderately emetogenic chemotherapy. PATIENTS AND METHODS: In this double-blind, parallel-group study, patients naive to emetogenic chemotherapy (N = 1,085) who were scheduled to receive cyclophosphamide- (500 to 1,200 mg/m2) or carboplatin (> or = 300 mg/m2) based chemotherapy, were randomized to receive either oral granisetron (n = 542) or I.V. ondansetron (n = 543). Efficacy assessments included the proportion of patients in each treatment group with total control over the 24 and 48 hours following chemotherapy initiation, as well as incidence and severity of nausea and emesis and use of antiemetic rescue medication. Prophylactic corticosteroids were allowed. Safety assessment was based on patients' reports of adverse experiences. RESULTS: Approximately 80% of patients received prophylactic corticosteroids. Single-dose oral granisetron (2 mg) and I.V. ondansetron (32 mg) resulted in equivalent levels of total emetic control during the first 48 hours after chemotherapy. The proportion of nausea- and emesis-free patients at 24 and 48 hours were also approximately equivalent. The most commonly reported adverse experiences were headache, asthenia, and constipation. More patients who received ondonsetron than granisetron reported dizziness (9.6% v 5.4%, respectively; P = .011) and abnormal vision (4.2% v 0.6%, respectively; P < .001). CONCLUSION: A single oral dose of granisetron (2 mg) resulted in equivalent levels of antiemetic protection as I.V. ondansetron (32 mg). Both agents were well tolerated, although more dizziness and abnormal vision were reported with ondansetron. Because the two antiemetic regimens exhibited equivalent efficacies, additional factors such as convenience and cost of therapy should be considered.

Single-dose oral granisetron has equivalent antiemetic efficacy to intravenous ondansetron for highly emetogenic cisplatin-based chemotherapy.

PURPOSE: To compare the antiemetic efficacy of a single dose of an oral antiemetic (granisetron 2 mg) with a single dose of an intravenous (i.v.) antiemetic (ondansetron 32 mg) given before cisplatin-based chemotherapy. PATIENTS AND METHODS: This was a multicenter, randomized, double-blind, parallel-group study. Patients (N = 1,054) scheduled to receive cisplatin (> or = 60 mg/m2)-based chemotherapy were randomized to receive either 2 mg of oral granisetron tablets 1 hour before chemotherapy (n = 534) or i.v. ondansetron (32 mg) 30 minutes before chemotherapy (n = 520). The primary efficacy end point was total control (no emesis, no nausea, and no use of antiemetic rescue medication) over the initial 24 hours after the start of chemotherapy. Dexamethasone or methylprednisolone were permitted, but not required, as concomitant prophylactic antiemetics. RESULTS: Total control was equivalent 24 hours after cisplatin chemotherapy for single-dose oral granisetron (54.7%) and i.v. ondansetron (58.3%) (95% confidence interval [CI], -9.6 to 2.4). Similar proportions of patients remained nausea-free in the granisetron group (55.4%) and the ondansetron group (59%) (95% CI, -9.6 to 2.4). The rate of complete control of emesis was 61.2% in the granisetron group and 67.1% in the ondansetron group (95% CI, -11.7 to -0.1). Both treatment regimens were well tolerated, with similar patterns of adverse reactions, generally of a mild degree. The most common side effects included constipation (14%), headache (15%), and diarrhea (10%). CONCLUSION: Oral granisetron, administered as a single 2-mg dose, provided equivalent total antiemetic control when compared with i.v. ondansetron (32 mg) in patients who received highly emetogenic, cisplatin-based chemotherapy.

Discussion of "Combining Health Data Uses to Ignite Health System Learning".

This article is part of a For-Discussion-Section of Methods of Information in Medicine about the paper "Combining Health Data Uses to Ignite Health System Learning" written by John D. Ainsworth and Iain E. Buchan [1]. It is introduced by an editorial. This article contains the combined commentaries invited to independently comment on the paper of Ainsworth and Buchan. In subsequent issues the discussion can continue through letters to the editor. With these comments on the paper "Combining Health Data Uses to Ignite Health System Learning", written by John D. Ainsworth and Iain E. Buchan [1], the journal seeks to stimulate a broad discussion on new ways for combining data sources for the reuse of health data in order to identify new opportunities for health system learning. An international group of experts has been invited by the editor of Methods to comment on this paper. Each of the invited commentaries forms one section of this paper.

Central inhibition of gonadotropin-releasing hormone secretion in the growth-restricted hypogonadotropic female sheep.

Growth retardation induced by dietary restriction results in hypogonadotropism, and thus, puberty is delayed. The present studies determined 1) whether reduced LH secretion in the growth-retarded condition is due to a reduction in the frequency and/or in the amplitude of GnRH secretion, and 2) whether the mechanism regulating LH secretion is being actively inhibited via central mechanisms. To determine whether GnRH pulse frequency and/or amplitude are reduced during growth restriction, blood samples were simultaneously collected from pituitary portal blood for GnRH and from jugular blood for LH determinations over a 4-h period in ovariectomized lambs (52 wk of age) that were either growth restricted (28 kg; n = 8) or growing normally (60 kg; n = 7). As expected, the growth-restricted females were hypogonadotropic and exhibited a long LH interpulse interval compared with the normally growing females. However, although the GnRH interpulse interval was longer in the growth-restricted lambs compared with that in the normally growing lambs, the pattern of GnRH secretion did not directly correspond with that of LH secretion in the growth-restricted group. In addition, high amplitude GnRH pulses that coincided with LH pulses and small, low amplitude GnRH pulses without a concomitant LH pulse occurred. The second study tested the hypothesis that diet-induced hypogonadotropism is the result of actively inhibited central mechanisms by investigating the effects of the nonspecific central nervous system inhibitor, sodium pentobarbital, on pulsatile LH secretion in the growth-restricted lamb. Serial blood samples were collected from 11 ovariectomized lambs that were maintained at weaning weight (approximately 20 kg) by reduced diet. After a 4-h pretreatment period, six of the lambs were anesthetized with sodium pentobarbital for 4 h; the other five lambs were untreated and served as controls. Pentobarbital anesthesia reduced the LH interpulse interval (increased the frequency) and increased mean LH levels. These findings suggest that during growth restriction hypogonadotropism arises from a central inhibition of GnRH neurons and is manifest as a decrease in both frequency and amplitude of GnRH pulses.

Recombinant human follicle-stimulating hormone stimulates multiple follicular growth, but minimal estrogen production in gonadotropin-releasing hormone antagonist-treated monkeys: examining the role of luteinizing hormone in follicular development and steroidogenesis.

The two-cell theory predicts that follicular steroidogenesis requires the coordinate actions of both FSH and LH; however, the role of LH in follicular growth is less clear. The present study was designed to investigate the relative importance of LH and FSH in follicular growth and steroidogenesis. Cynomolgus monkeys were treated with a GnRH antagonist (antide; 3 mg/kg.day) for 20 days beginning in the midluteal phase of the menstrual cycle. After 10 days of antide administration, monkeys were injected with recombinant human FSH (rhFSH; 10 IU; n = 3), human menopausal gonadotropin (hMG; 10 IU; n = 3), or FSH plus 0.5 IU LH (n = 3) twice daily for 10 days. rhFSH stimulated multiple follicular development; however, peak serum estradiol levels were only 943 +/- 195 pmol/L. In contrast, monkeys treated with the same dose of hMG had significantly higher (P < 0.05) peak estradiol levels (6013 +/- 1322 pmol/L). The addition of 0.5 IU LH to the rhFSH treatment resulted in serum estradiol levels similar to those in monkeys treated with rhFSH only. Importantly, no differences in follicle number or size were evident among these treatment groups. Follicular fluid estradiol levels were consistent with serum levels (rhFSH, 187 +/- 11 nmol/L; hMG, 1531 +/- 173 nmol/L). Even larger proportional differences in follicular fluid androstenedione (rhFSH 13.6 +/- 1.4 nmol/L; hMG, 307 +/- 97.7 nmol/L) levels were found. The results in this LH-deficient primate model suggest that FSH alone is capable of stimulating ovarian follicular growth; however, the resulting follicles manifest minimal estradiol production, probably due to deficiencies in the LH-induced precursors to estradiol.

Serum lipoprotein responses during active and stable weight reduction in reproductive obese females.

An increase in high density lipoprotein-cholesterol (HDL-C) and a reduction in low density lipoprotein-cholesterol (LDL-C) accompany weight reduction in obese males. In contrast, obese females have had variable responses in these two lipoproteins after weight reduction. To evaluate the effects of weight reduction in obese women, 15 morbidly obese eugonadotropic women of reproductive age had serum lipids and lipoproteins measured before and after achieving a stable and reduced weight by either diet and/or a gastric stapling procedure. Total testosterone (T), free testosterone (free T), and testosterone-binding globulin serum concentrations were also determined before and after achieving a stable reduced weight to assess the role of androgens in modulating any lipoprotein changes. In 10 subjects, lipid analysis was also performed during active weight loss. Total serum triglycerides fell from 106 +/- 53 to 76 +/- 30 mg/dl during active weight loss (P less than 0.025). Total cholesterol, LDL-C, HDL-C, and the LDL-C to HDL-C ratio did not change. In contrast, after achieving a stable reduced weight (mean weight reduction, 25.9 +/- 6.7 kg), HDL-C rose from 24 +/- 8 to 32 +/- 9 mg/dl (P less than 0.005). This was accompanied by a reduction in LDL-C from 145 +/- 23 to 135 +/- 30 mg/dl (P less than 0.01) and in the LDL-C to HDL-C ratio from 6.7 +/- 2.6 to 4.8 +/- 1.9 (P less than 0.001). Total triglycerides and total cholesterol were unchanged. After obtaining a stable reduced weight, testosterone-binding globulin increased and free T fell, but no significant correlation existed between the changes in androgens and the changes in lipoprotein responses. Thus, in morbidly obese women, weight reduction increases HDL-C and lowers LDL-C serum concentrations. The reduction in the LDL-C to HDL-C ratio suggests that weight loss may favorably reduce the risk of coronary artery disease in these patients. A concurrent reduction of free T with weight loss does not appear to be a major controlling influence in these lipoprotein alterations.