Infertility prevalence and the methods of estimation from 1990 to 2021: a systematic review and meta-analysis

STUDY QUESTION

What is the contemporary prevalence of infertility in world populations and how do they differ by methodological and study characteristics?

SUMMARY ANSWER

Pooled estimates of lifetime and period prevalence of 12-month infertility were 17.5% and 12.6%, respectively, but this varied by study population and methodological approach.

WHAT IS KNOWN ALREADY

Infertility affects millions of individuals worldwide. Accurate measures of its magnitude are needed to effectively address and manage the condition. There are distinct challenges and variation in how infertility is defined and measured, limiting comparability of estimates across studies. Further research is needed to understand whether and how differences in methodological approaches and study characteristics account for heterogeneity in estimates.

STUDY DESIGN SIZE DURATION

We conducted a systematic review and meta-analysis. Six electronic databases, websites of relevant organizations, and conference proceedings were systematically searched. Searches were limited to those published between 1 January 1990 and 11 March 2021, with no language restrictions.

PARTICIPANTS/MATERIALS SETTING METHODS

Descriptive and random-effects meta-analysis models were used to examine range of estimates and generate estimates of pooled lifetime and period prevalence of 12-month infertility, respectively, among representative populations. Meta-regression using restricted maximum likelihood was applied to account for definitional and study characteristics and to obtain adjusted estimates. Risk of bias was assessed with a validated tool.

MAIN RESULTS AND THE ROLE OF CHANCE

The search yielded 12 241 unique records of which 133 studies met the criteria for the systematic review. There were 65 and 69 studies that provided data for lifetime and period prevalence of 12-month infertility, respectively. Five methodological approaches were identified: prospective time-to-pregnancy (TTP) design, current duration design, retrospective TTP design, self-reported infertility measure and constructed infertility measure. Ranges for lifetime (3.3-39.7%) and period estimates (1.6-34.0%) were similar and wide even after accounting for methodological and study characteristics. Pooled estimates of lifetime and period prevalence were 17.5% (95% CI: 15.0, 20.3, n = 37 studies, I ² = 99.5%) and 12.6% (95% CI: 10.7, 14.6, n = 43 studies, I ² = 99.8%), respectively, with some variation in magnitude by region and methodological approach, but with most CIs overlapping.

LIMITATIONS REASONS FOR CAUTION

Pooled estimates generated from meta-analysis were derived from 12-month infertility prevalence estimates that were heterogeneous across different domains, even after adjusting for definitional and study characteristics. The number of studies was small for certain strata from which pooled estimates were derived (e.g. there were only two studies for lifetime prevalence in Africa).

WIDER IMPLICATIONS OF THE FINDINGS

While findings show a high prevalence of infertility globally and regionally, it also reveals variation in measures to ascertain and compare infertility prevalence. More systematic and comprehensive collection of data using a consistent definition is needed to improve infertility prevalence estimates at global, regional and country-levels.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the World Health Organization. The authors have no conflicts of interest.

REGISTRATION NUMBER

PROSPERO CRD42020211704.

Proton deflectometry with in situ x-ray reference for absolute measurement of electromagnetic fields in high-energy-density plasmas

We report a technique of proton deflectometry that uses a grid and an in situ reference x-ray grid image for precise measurements of magnetic fields in high-energy-density plasmas. A D³He fusion implosion provides a bright point source of both protons and x-rays, which is split into beamlets by a grid. The protons undergo deflections as they propagate through the plasma region of interest, whereas the x-rays travel along straight lines. The x-ray image, therefore, provides a zero-deflection reference image. The line-integrated magnetic fields are inferred from the shifts of beamlets between the deflected (proton) and reference (x-ray) images. We developed a system for analysis of these data, including automatic algorithms to find beamlet locations and to calculate their deflections from the reference image. The technique is verified in an experiment performed at OMEGA to measure a nonuniform magnetic field in vacuum and then applied to observe the interaction of an expanding plasma plume with the magnetic field.

Brain-mimicking phantom for biomechanical validation of motion sensitive MR imaging techniques

Motion sensitive MR imaging techniques allow for the non-invasive evaluation of biological tissues by using different excitation schemes, including physiological/intrinsic motions caused by cardiac pulsation or respiration, and vibrations caused by an external actuator. The mechanical biomarkers extracted through these imaging techniques have been shown to hold diagnostic value for various neurological disorders and conditions. Amplified MRI (aMRI), a cardiac gated imaging technique, can help track and quantify low frequency intrinsic motion of the brain. As for high frequency actuation, the mechanical response of brain tissue can be measured by applying external high frequency actuation in combination with a motion sensitive MR imaging sequence called Magnetic Resonance Elastography (MRE). Due to the frequency-dependent behavior of brain mechanics, there is a need to develop brain phantom models that can mimic the broadband mechanical response of the brain in order to validate motion-sensitive MR imaging techniques. Here, we have designed a novel phantom test setup that enables both the low and high frequency responses of a brain-mimicking phantom to be captured, allowing for both aMRI and MRE imaging techniques to be applied on the same phantom model. This setup combines two different vibration sources: a pneumatic actuator, for low frequency/intrinsic motion (1 Hz) for use in aMRI, and a piezoelectric actuator for high frequency actuation (30-60 Hz) for use in MRE. Our results show that in MRE experiments performed from 30 Hz through 60 Hz, propagating shear waves attenuate faster at higher driving frequencies, consistent with results in the literature. Furthermore, actuator coupling has a substantial effect on wave amplitude, with weaker coupling causing lower amplitude wave field images, specifically shown in the top-surface shear loading configuration. For intrinsic actuation, our results indicate that aMRI linearly amplifies motion up to at least an amplification factor of 9 for instances of both visible and sub-voxel motion, validated by varying power levels of pneumatic actuation (40%-80% power) under MR, and through video analysis outside the MRI scanner room. While this investigation used a homogeneous brain-mimicking phantom, our setup can be used to study the mechanics of non-homogeneous phantom configurations with bio-interfaces in the future.

Lessons learnt from the field: a qualitative evaluation of adolescent experiences of a universal mental health education program

teen Mental Health First Aid (teenMHFA) is a school-based mental health program that trains adolescents to support peers who are experiencing mental health problems or crises. The program has been evaluated for adolescents aged 15-18 years as part of a randomized controlled trial, however qualitative feedback from students on their perceptions of the program is yet to be explored. The current study describes the perspectives of students who took part in the trial. Feedback on the perceived strengths and weaknesses of the program was provided by 979 Year 10 students (M = 15.82 years, female = 43.94%, English as a first language = 72.77%) at four government funded public schools in Melbourne, Australia via online surveys. A content and thematic analysis was performed on the data using a six-step process. Students generally found the program relevant and they connected with the visual material, personal stories and interactive activities. Suggestions for improvements included encouraging active student participation in classroom discussion and providing opportunities to practice skills. School-based mental health education can benefit from input from stakeholder perspectives, particularly when designing mental health content for delivery by external trainers.

Heterogeneous mass distribution of the rubble-pile asteroid (101955) Bennu

The gravity field of a small body provides insight into its internal mass distribution. We used two approaches to measure the gravity field of the rubble-pile asteroid (101955) Bennu: (i) tracking and modeling the spacecraft in orbit about the asteroid and (ii) tracking and modeling pebble-sized particles naturally ejected from Bennu's surface into sustained orbits. These approaches yield statistically consistent results up to degree and order 3, with the particle-based field being statistically significant up to degree and order 9. Comparisons with a constant-density shape model show that Bennu has a heterogeneous mass distribution. These deviations can be modeled with lower densities at Bennu's equatorial bulge and center. The lower-density equator is consistent with recent migration and redistribution of material. The lower-density center is consistent with a past period of rapid rotation, either from a previous Yarkovsky-O'Keefe-Radzievskii-Paddack cycle or arising during Bennu's accretion following the disruption of its parent body.

Hemispherical differences in the shape and topography of asteroid (101955) Bennu

We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu's southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu's history.

The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements

The top-shape morphology of asteroid (101955) Bennu is commonly found among fast-spinning asteroids and binary asteroid primaries, and might have contributed significantly to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of OSIRIS-REx, we find a significant transition in Bennu's surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennu's surface has been most recently migrating towards its equator (given Bennu's increasing spin rate), we infer that Bennu's surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior has a distribution of voids and boulders. The presence of such heterogeneity and Bennu's top-shape is consistent with spin-induced failure at some point in its past, although the manner of its failure cannot be determined yet. Future measurements by the OSIRIS-REx spacecraft will give additional insights and may resolve questions regarding the formation and evolution of Bennu's top-shape morphology and its link to the formation of binary asteroids.

Shape of (101955) Bennu indicative of a rubble pile with internal stiffness

The shapes of asteroids reflect interplay between their interior properties and the processes responsible for their formation and evolution as they journey through the Solar System. Prior to the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission, Earth-based radar imaging gave an overview of (101955) Bennu's shape. Here, we construct a high-resolution shape model from OSIRIS-REx images. We find that Bennu's top-like shape, considerable macroporosity, and prominent surface boulders suggest that it is a rubble pile. High-standing, north-south ridges that extend from pole to pole, many long grooves, and surface mass wasting indicate some low levels of internal friction and/or cohesion. Our shape model indicates that, similar to other top-shaped asteroids, Bennu formed by reaccumulation and underwent past periods of fast spin leading to its current shape. Today, Bennu might follow a different evolutionary pathway, with interior stiffness permitting surface cracking and mass wasting.

Challenges of Francisella classification exemplified by an atypical clinical isolate

The accumulation of sequenced Francisella strains has made it increasingly apparent that the 16S rRNA gene alone is not enough to stratify the Francisella genus into precise and clinically useful classifications. Continued whole-genome sequencing of isolates will provide a larger base of knowledge for targeted approaches with broad applicability. Additionally, examination of genomic information on a case-by-case basis will help resolve outstanding questions regarding strain stratification. We report the complete genome sequence of a clinical isolate, designated here as F. novicida-like strain TCH2015, acquired from the lymph node of a 6-year-old male. Two features were atypical for F. novicida: exhibition of functional oxidase activity and additional gene content, including proposed virulence determinants. These differences, which could potentially impact virulence and clinical diagnosis, emphasize the need for more comprehensive methods to profile Francisella isolates. This study highlights the value of whole-genome sequencing, which will lead to a more robust database of environmental and clinical genomes and inform strategies to improve detection and classification of Francisella strains.

Use of antibiotics in paediatric long-term care facilities

BACKGROUND

Adult long-term care (LTC) facilities have high rates of antibiotic use, raising concerns about antimicrobial resistance. Few studies have examined antibiotic use in paediatric LTC facilities.

AIM

To describe antibiotic use in three paediatric LTC facilities and to describe the factors associated with use.

METHODS

A retrospective cohort study was conducted from September 2012 to December 2015 in three paediatric LTC facilities. Medical records were reviewed for demographics, healthcare-associated infections (HAIs), antimicrobial use and diagnostic testing. Logistic regression was used to identify predictors for antibiotic use. The association between susceptibility testing results and appropriate antibiotic coverage was determined using Chi-squared test.

FINDINGS

Fifty-eight percent (413/717) of residents had at least one HAI, and 79% (325/413) of these residents were treated with at least one antibiotic course, totalling 2.75 antibiotic courses per 1000 resident-days. Length of enrolment greater than one year, having a neurological disorder, having a tracheostomy, and being hospitalized at least once during the study period were significantly associated with receiving antibiotics when controlling for facility (all P < 0.001). Diagnostic testing was performed for 40% of antibiotic-treated HAIs. Eighty-six percent of antibiotic courses for identified bacterial pathogens (201/233) provided appropriate coverage. Access to susceptibility testing was not associated with appropriate antibiotic choice (P = 0.26).

CONCLUSION

Use of antibiotics in paediatric LTC facilities is widespread. There is further need to assess antibiotic use in paediatric LTC facilities. Evaluation of the adverse outcomes associated with inappropriate antibiotic use, including the prevalence of resistant organisms in paediatric LTC facilities, is critical.

Activating transcription factor 3 promotes loss of the acinar cell phenotype in response to cerulein-induced pancreatitis in mice

Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. Of importance, ATF3-dependent regulation of these genes was observed only upon induction of pancreatitis, with pathways involved in inflammation, acinar cell differentiation, and cell junctions being specifically targeted. Characterizing expression of transcription factors that affect acinar cell differentiation suggested that acinar cells lacking ATF3 maintain a mature cell phenotype during pancreatitis, a finding supported by maintenance of junctional proteins and polarity markers. As a result, Atf3-/- pancreatic tissue displayed increased tissue damage and inflammatory cell infiltration at early time points during injury but, at later time points, showed reduced acinar-to-duct cell metaplasia. Thus our results reveal a critical role for ATF3 as a key regulator of the acinar cell transcriptional response during injury and may provide a link between chronic pancreatitis and PDAC.

Outcomes with multimodal therapy for elderly patients with rectal cancer

BACKGROUND

Treatment guidelines for stage II and III rectal cancer include neoadjuvant chemoradiotherapy, surgery and postoperative adjuvant chemotherapy. Although data support this recommendation in younger patients, it is unclear whether this benefit can be extrapolated to elderly patients (aged 75 years or older).

METHODS

This was a retrospective review of patients aged at least 75 years with stage II or III rectal cancer who underwent surgery with curative intent from 1996 to 2013 at the Mayo Clinic. Kaplan-Meier analysis and log rank test were used to compare overall survival between therapy groups. Cox proportional hazards model was used to estimate the independent effect of treatment group on survival.

RESULTS

A total of 160 elderly patients (median age 80 years) with stage II (66) and stage III (94) rectal cancer underwent surgical resection. Only 30·0 and 33·8 per cent received neoadjuvant or adjuvant therapy respectively. Among patients with stage II disease, there was no significant difference in 60-month survival between patients who received any additional therapy and those who had surgery alone (55 versus 38 per cent respectively; P = 0·184), whereas additional therapy improved survival in patients with stage III tumours (58 versus 30 per cent respectively; P = 0·007). Multivariable analysis found a survival benefit for additional therapy in elderly patients with stage III disease (hazard ratio 0·58, 95 per cent c.i. 0·34 to 0·98).

CONCLUSION

A multimodal approach in elderly patients with stage III rectal cancer improved oncological outcomes.

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

PURPOSE

Descriptions of the structure of brain tissue as a porous cellular matrix support application of a poroelastic (PE) mechanical model which includes both solid and fluid phases. However, the majority of brain magnetic resonance elastography (MRE) studies use a single phase viscoelastic (VE) model to describe brain tissue behavior, in part due to availability of relatively simple direct inversion strategies for mechanical property estimation. A notable exception is low frequency intrinsic actuation MRE, where PE mechanical properties are imaged with a nonlinear inversion algorithm.

METHODS

This paper investigates the effect of model choice at each end of the spectrum of in vivo human brain actuation frequencies. Repeat MRE examinations of the brains of healthy volunteers were used to compare image quality and repeatability for each inversion model for both 50 Hz externally produced motion and ≈1 Hz intrinsic motions. Additionally, realistic simulated MRE data were generated with both VE and PE finite element solvers to investigate the effect of inappropriate model choice for ideal VE and PE materials.

RESULTS

In vivo, MRE data revealed that VE inversions appear more representative of anatomical structure and quantitatively repeatable for 50 Hz induced motions, whereas PE inversion produces better results at 1 Hz. Reasonable VE approximations of PE materials can be derived by equating the equivalent wave velocities for the two models, provided that the timescale of fluid equilibration is not similar to the period of actuation. An approximation of the equilibration time for human brain reveals that this condition is violated at 1 Hz but not at 50 Hz. Additionally, simulation experiments when using the "wrong" model for the inversion demonstrated reasonable shear modulus reconstructions at 50 Hz, whereas cross-model inversions at 1 Hz were poor quality. Attenuation parameters were sensitive to changes in the forward model at both frequencies, however, no spatial information was recovered because the mechanisms of VE and PE attenuation are different.

CONCLUSIONS

VE inversions are simpler with fewer unknown properties and may be sufficient to capture the mechanical behavior of PE brain tissue at higher actuation frequencies. However, accurate modeling of the fluid phase is required to produce useful mechanical property images at the lower frequencies of intrinsic brain motions.

Fisheries Closed Areas Strengthen Scallop Larval Settlement and Connectivity Among Closed Areas and Across International Open Fishing Grounds: A Model Study

This study examined whether a measured increase in average body size of adult sea scallops inside three fishery closed areas on Georges Bank (GB), United States (US), was sufficient to increase larval supply to closed areas and open fishing areas in both US and Canadian areas of the Bank. The effects of adult scallop density-at-size and fecundity-at-size on egg production were compared among open and closed fishery areas, countries, and time periods before and after the closed areas were established. Estimated egg production was then used to define spawning conditions in a coupled biological-physical larval tracking model that simulated larval development, mortality, and dispersal. Results showed that order of magnitude increases in larval settlement after closure were facilitated by increases in size-dependant egg production inside and dispersal from Closed Areas I and II, but not Nantucket Lightship Closed Area. The distributions of both egg production and larval settlement became more uniform across the Bank, causing the relative contribution of Canadian larvae to US scallop aggregations to decrease after establishment of Closed Areas I and II. Decreases in small and medium-sized scallop density in Canada and decreases in large scallops over the US-Southern Flank after closure caused local declines in egg production but were not sufficient to negatively affect larval settlement at the regional scale. Our model suggests that the establishment of fishery closed areas on GB considerably strengthened larval supply and settlement within and among several adult scallop aggregations.

Environmental chemical exposure may contribute to uterine cancer development: studies with tetrabromobisphenol A

Tetrabromobisphenol A (TBBPA), a widely used flame retardant, caused uterine tumors in rats. In this study, TBBPA was administered to male and female Wistar Han rats and B6C3F1/N mice by oral gavage in corn oil for 2 years at doses up to 1,000 mg/kg. TBBPA induced uterine epithelial tumors including adenomas, adenocarcinomas, and malignant mixed Müllerian tumors (MMMTs). In addition, endometrial epithelial atypical hyperplasia occurred in TBBPA-treated rats. Also found to be related to TBBPA treatment, but at lower incidence and at a lower statistical significance, were testicular tumors in rats, and hepatic tumors, hemangiosarcomas (all organs), and intestinal tumors in male mice. It is hypothesized that the TBBPA uterine tumor carcinogenic mechanisms involve altered estrogen levels and/or oxidative damage. TBBPA treatment may affect hydroxysteroid-dehydrogenase-17β (HSD17β) and/or sulfotransferases, enzymes involved in estrogen homeostasis. Metabolism of TBBPA may also result in the formation of free radicals. The finding of TBBPA-mediated uterine cancer in rats is of concern because TBBPA exposure is widespread and endometrial tumors are a common malignancy in women. Further work is needed to understand TBBPA cancer mechanisms.

Silencing of the Fibroblast growth factor 21 gene is an underlying cause of acinar cell injury in mice lacking MIST1

Fibroblast growth factor 21 (FGF21) is a key regulator of metabolism under conditions of stress such as starvation, obesity, and hypothermia. Rapid induction of FGF21 is also observed in experimental models of pancreatitis, and FGF21 reduces tissue damage observed in these models, suggesting a nonmetabolic function. Pancreatitis is a debilitating disease with significant morbidity that greatly increases the risk of pancreatic ductal adenocarcinoma. The goals of this study were to examine the regulation and function of FGF21 in acinar cell injury, specifically in a mouse model of pancreatic injury (Mist1(-/-)). Mist1(-/-) mice exhibit acinar cell disorganization, decreased acinar cell communication and exocytosis, and increased sensitivity to cerulein-induced pancreatitis (CIP). Examination of Fgf21 expression in Mist1(-/-) mice by qRT-PCR, Northern blot, and Western blot analyses showed a marked decrease in pancreatic Fgf21 expression before and after induction of CIP compared with C57Bl/6 mice. To determine whether the loss of FGF21 accounted for the Mist1(-/-) phenotypes, we generated Mist1(-/-) mice overexpressing human FGF21 from the ApoE promoter (Mist1(-/-)ApoE-FGF21). Reexpression of FGF21 partially mitigated pancreatic damage in Mist1(-/-) tissue based on reduced intrapancreatic enzyme activation, reduced expression of genes involved in fibrosis, and restored cell-cell junctions. Interestingly, alteration of Fgf21 expression in Mist1(-/-) tissue was not simply due to a loss of direct transcriptional regulation by MIST1. Chromatin immunopreciptation indicated that the loss of Fgf21 in the Mist1(-/-) pancreas is due, in part, to epigenetic silencing. Thus, our studies identify a new role for FGF21 in reducing acinar cell injury and uncover a novel mechanism for regulating Fgf21 gene expression.

Circulating bovine pregnancy associated glycoproteins are associated with late embryonic/fetal survival but not ovulatory follicle size in suckled beef cows

The objective was to examine the relationship between ovulatory follicle size and embryo and fetal survival by using circulating concentrations of bovine pregnancy associated glycoproteins (bPAG) to detect the presence of an embryo or fetus and monitor placental function. Before examining the relationship between bPAG, ovulatory follicle size, and embryo and fetal survival, the half-life of bPAG was determined in Exp. 1. The half-life of bPAG after PGF2α-induced abortion on d 32 to 36 postinsemination was 35.8 ± 21.9 h (mean ± SD; range 7.1 to 78.5 h). In Exp. 2, suckled beef cows (n = 91) were treated with the CO-Synch protocol (GnRH on d -9, PGF2α on d -2, and GnRH and AI 48 h later [d 0]) and classified into 1 of 2 ovulatory follicle size groups: 1) small follicle (<12.5 mm; n = 25) or 2) large follicle (≥ 12.5 mm; n = 66). The first increase (P < 0.0001) in serum bPAG occurred in pregnant cows on d 24 after insemination and circulating bPAG decreased before a decrease in progesterone in 3 of 4 cows that lost an embryo or fetus. Pattern of secretion of bPAG in serum from d 24 to 60 after insemination (d 0) was affected by day (P < 0.0001), but not ovulatory follicle size. In Exp. 3, suckled beef cows (n = 1164) were administered the CO-Synch protocol either with (donor cows; n = 810) or without (recipient cows; n = 354) AI on d 0. Single embryos (n = 394) or oocytes (n = 45) were recovered from the donor cows [d 7; embryo transfer (ET)] and all live embryos were transferred into recipients the same day. Cows were classified on d 0 as having a small (<12.5 mm) or large (≥ 12.5 mm) ovulatory follicle, and randomly chosen as donors or recipients to remove confounding effects of ovulatory follicle size on fertility. Serum concentration of bPAG at d 28 was not affected by ovulatory follicle size (P = 0.85), embryo stage at ET (P = 0.75), embryo quality at ET (P = 0.64), estradiol at GnRH2 (P = 0.62) or serum progesterone at ET (d7; P = 0.14). Compared with cows that maintained pregnancy (n = 176), cows that exhibited late embryonic or fetal mortality (n = 19) after d 28 had decreased (P < 0.05) concentrations of bPAG on d 28. In summary, there was no relationship between serum bPAG and ovulatory follicle size or embryo stage or quality at ET; however, cows that lost an embryo after d 28 had reduced concentrations of bPAG on d 28 compared with cows that maintained pregnancy.

Multiresolution MR elastography using nonlinear inversion

PURPOSE

Nonlinear inversion (NLI) in MR elastography requires discretization of the displacement field for a finite element (FE) solution of the "forward problem", and discretization of the unknown mechanical property field for the iterative solution of the "inverse problem". The resolution requirements for these two discretizations are different: the forward problem requires sufficient resolution of the displacement FE mesh to ensure convergence, whereas lowering the mechanical property resolution in the inverse problem stabilizes the mechanical property estimates in the presence of measurement noise. Previous NLI implementations use the same FE mesh to support the displacement and property fields, requiring a trade-off between the competing resolution requirements.

METHODS

This work implements and evaluates multiresolution FE meshes for NLI elastography, allowing independent discretizations of the displacements and each mechanical property parameter to be estimated. The displacement resolution can then be selected to ensure mesh convergence, and the resolution of the property meshes can be independently manipulated to control the stability of the inversion.

RESULTS

Phantom experiments indicate that eight nodes per wavelength (NPW) are sufficient for accurate mechanical property recovery, whereas mechanical property estimation from 50 Hz in vivo brain data stabilizes once the displacement resolution reaches 1.7 mm (approximately 19 NPW). Viscoelastic mechanical property estimates of in vivo brain tissue show that subsampling the loss modulus while holding the storage modulus resolution constant does not substantially alter the storage modulus images. Controlling the ratio of the number of measurements to unknown mechanical properties by subsampling the mechanical property distributions (relative to the data resolution) improves the repeatability of the property estimates, at a cost of modestly decreased spatial resolution.

CONCLUSIONS

Multiresolution NLI elastography provides a more flexible framework for mechanical property estimation compared to previous single mesh implementations.

Activation of protein kinase Cδ leads to increased pancreatic acinar cell dedifferentiation in the absence of MIST1

Pancreatic ductal adenocarcinoma (PDAC) has a 5 year survival rate post-diagnosis of < 5%. Individuals with chronic pancreatitis (CP) are 20-fold more likely to develop PDAC, making it a significant risk factor for PDAC. While the relationship for the increased susceptibility to PDAC is unknown, loss of the acinar cell phenotype is common to both pathologies. Pancreatic acinar cells can dedifferentiate or trans-differentiate into a number of cell types including duct cells, β cells, hepatocytes and adipocytes. Knowledge of the molecular pathways that regulate this plasticity should provide insight into PDAC and CP. MIST1 (encoded by Bhlha15 in mice) is a transcription factor required for complete acinar cell maturation. The goal of this study was to examine the plasticity of acinar cells that do not express MIST1 (Mist1(-/-) ). The fate of acinar cells from C57Bl6 or congenic Mist1(-/-) mice expressing an acinar specific, tamoxifen-inducible Cre recombinase mated to Rosa26 reporter LacZ mice (Mist1(CreERT/-) R26r) was determined following culture in a three-dimensional collagen matrix. Mist1(CreERT/-) R26r acini showed increased acinar dedifferentiation, formation of ductal cysts and transient increases in PDX1 expression compared to wild-type acinar cells. Other progenitor cell markers, including Foxa1, Sox9, Sca1 and Hes1, were elevated only in Mist1(-/-) cultures. Analysis of protein kinase C (PKC) isoforms by western blot and immunofluorescence identified increased PKCε accumulation and nuclear localization of PKCδ that correlated with increased duct formation. Treatment with rottlerin, a PKCδ-specific inhibitor, but not the PKCε-specific antagonist εV1-2, reduced acinar dedifferentiation, progenitor gene expression and ductal cyst formation. Immunocytochemistry on CP or PDAC tissue samples showed reduced MIST1 expression combined with increased nuclear PKCδ accumulation. These results suggest that the loss of MIST1 is a common event during PDAC and CP and events that affect MIST1 function and expression may increase susceptibility to these pathologies.

The absence of MIST1 leads to increased ethanol sensitivity and decreased activity of the unfolded protein response in mouse pancreatic acinar cells

BACKGROUND

Alcohol abuse is a leading cause of pancreatitis in humans. However, rodent models suggest that alcohol only sensitizes the pancreas to subsequent insult, indicating that additional factors play a role in alcohol-induced pancreatic injury. The goal of this study was to determine if an absence of MIST1, a transcription factor required for complete differentiation of pancreatic acinar cells in mice, increased the sensitivity to alcohol.

METHODS

Two to four month-old mice lacking MIST1 (Mist1(-/-)) or congenic C57 Bl6 mice were placed on a Lieber-DeCarli diet (36% of total kcal from ethanol and fat), a control liquid diet (36% kcal from fat) or a regular breeding chow diet (22% kcal from fat). After six weeks, pancreatic morphology was assessed. Biochemical and immunofluorescent analysis was used to assess mediators of the unfolded protein response (UPR).

RESULTS

Ethanol-fed Mist1(-/-) mice developed periductal accumulations of inflammatory cells that did not appear in wild type or control-fed Mist1(-/-) mice. Wild type mice fed diets high in ethanol or fat showed enhancement of the UPR based on increased accumulation of peIF2α and spliced XBP1. These increases were not observed in Mist1(-/-) pancreatic tissue, which had elevated levels of UPR activity prior to diet exposure. Indeed, exposure to ethanol resulted in a reduction of UPR activity in Mist1(-/-) mice.

CONCLUSIONS

Our findings suggest that an absence of MIST1 increases the sensitivity to ethanol that correlated with decreased activity of the UPR. Therefore, events that affect the expression and/or function of MIST1 may be confounding factors in pancreatitis.

Fibroblast growth factor 21 reduces the severity of cerulein-induced pancreatitis in mice

BACKGROUND & AIMS

Fibroblast growth factor 21 (FGF21) acts as a hormonal regulator during fasting and is involved in lipid metabolism. Fgf21 gene expression is regulated by peroxisome proliferator-activated receptor (PPAR)-dependent pathways, which are enhanced during pancreatitis. Therefore, the aim of this study was to investigate FGF21's role in pancreatic injury.

METHODS

Fgf21 expression was quantified during cerulein-induced pancreatitis (CIP) or following mechanical or thapsigargin-induced stress through Northern blot analysis, in situ hybridization, and quantitative reverse transcription polymerase chain reaction. FGF21 protein was quantified by Western blot analysis. Isolated acinar cells or AR42J acinar cells were treated with recombinant FGF21 protein, and extracellular regulated kinase 1/2 activation was examined. The severity of CIP was compared between wild-type mice and mice overexpressing FGF21 (FGF21Tg) or harboring a targeted deletion of Fgf21 (Fgf21(-/-)).

RESULTS

Acinar cell Fgf21 expression markedly increased during CIP and following injury in vitro. Purified FGF21 activated the extracellular regulated kinase 1/2 pathway in pancreatic acinar cells. The severity of CIP is inversely correlated to FGF21 expression because FGF21Tg mice exhibited decreased serum amylase and decreased pancreatic stellate cell activation, whereas Fgf21(-/-) mice had increased serum amylase and tissue damage. The expression of Fgf21 was also inversely correlated to expression of Early growth response 1, a proinflammatory and profibrotic transcription factor.

CONCLUSIONS

These studies suggest a novel function for Fgf21 as an immediate response gene protecting pancreatic acini from overt damage.

Expression of epidermal growth factor receptor and vascular endothelial growth factor in malignant canine epithelial nasal tumours

Epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) signalling pathways play a role in carcinogenesis. Inhibition of EGF receptor (EGFR) and of VEGF is effective in increasing the radiation responsiveness of neoplastic cells both in vitro and in human trials. In this study, immunohistochemical evaluation was employed to determine and characterize the potential protein expression levels and patterns of EGFR and VEGF in a variety of canine malignant epithelial nasal tumours. Of 24 malignant canine nasal tumours, 13 (54.2%) were positive for EGFR staining and 22 (91.7%) were positive for VEGF staining. The intensity and percentage of immunohistochemically positive neoplastic cells for EGFR varied. These findings indicate that EGFR and VEGF proteins were present in some malignant epithelial nasal tumours in the dogs, and therefore, it may be beneficial to treat canine patients with tumours that overexpress EGFR and VEGF with specific inhibitors in conjunction with radiation.

Identification of a transcription factor, BHLHB8, involved in mouse seminal vesicle epithelium differentiation and function

The seminal vesicle is a male accessory sex organ that develops from segments of the Wolffian duct adjacent to the urogenital sinus. It produces most of the seminal plasma in both humans and rodents. To date, very few transcription factors have been linked to the development and differentiation of seminal vesicles. In this study, we have examined the role of basic helix-loop-helix (BHLH) B8 transcription factor expressed at high levels in the adult seminal vesicle and during seminal gland differentiation. Immunofluorescent studies indicate that BHLHB8 is expressed within the epithelial layer of the seminal layer of the seminal vesicle following branching morphogenesis but prior to full maturation of cell morphology and function. Analysis of mice that do not express BHLHB8 (Bhlhb8(-/-)) indicates no deficiency in the initial development of the seminal vesicle. However, morphological and ultrastructural analysis indicates disruption of the epithelial cellular architecture. The seminal vesicle epithelial layer of 2-mo-old Bhlhb8(-/-) mice shows extensive cellular degeneration based on the appearance of reduced microvilli, altered granule size, and dilated endoplasmic reticulum and Golgi apparatus. The seminal vesicle epithelial cells also degenerate prematurely, as evidenced by disruption of nuclear architecture and significant accumulations of autophagic bodies. These results identify BHLHB8 as a regulator in establishing and stabilizing the secreting epithelial cells of the seminal vesicle.

Mice lacking the transcription factor Mist1 exhibit an altered stress response and increased sensitivity to caerulein-induced pancreatitis

Several animal models have been developed to investigate the pathobiology of pancreatitis, but few studies have examined the effects that altered pancreatic gene expression have in these models. In this study, the sensitivity to secretagogue-induced pancreatitis was examined in a mouse line that has an altered acinar cell environment due to the targeted deletion of Mist1. Mist1 is an exocrine specific transcription factor important for the complete differentiation and function of pancreatic acinar cells. Mice lacking the Mist1 gene [Mist1 knockout (KO) mice] exhibit cellular disorganization and functional defects in the exocrine pancreas but no gross morphological defects. Following the induction of pancreatitis with caerulein, a CCK analog, we observed elevated serum amylase levels, necrosis, and tissue damage in Mist1 KO mice, indicating increased pancreatic damage. There was also a delay in the regeneration of acinar tissue in Mist1 KO animals. Molecular profiling revealed an altered activation of stress response genes in Mist1 KO pancreatic tissue compared with wild-type (WT) tissue following the induction of pancreatitis. In particular, Western blot analysis for activating transcription factor 3 and phosphorylated eukaryotic initiation factor 2alpha (eIF2alpha), mediators of endoplasmic reticulum (ER) stress, indicated limited activation of this pathway in Mist1 KO animals compared with WT controls. Conversely, Mist1 KO pancreatic tissue exhibits increased expression of growth arrest and DNA damage inducible 34 protein, an inhibitor of eIF2alpha phosphorylation, before and after the induction of pancreatitis. These finding suggest that activation of the ER stress pathway is a protective event in the progression of pancreatitis and highlight the Mist1 KO mouse line as an important new model for studying the molecular events that contribute to the sensitivity to pancreatic injury.

Calibration of projector lens distortions

The distortions introduced into high-resolution transmission electron microscope (HRTEM) images by the projector lens system are an important source of systematic error for quantitative displacement and strain determination. Using geometric phase analysis of images of perfect crystals, we measured these errors for two different transmission electron microscopes. Local magnification varies by as much as 5%, and rotation can reach 2 degrees across a typical image. Our experimental results are compared with theory, and optical pincushion and spiral distortion coefficients are determined. A method for calibrating and removing these distortions is presented that enables quantification to 0.1% strain and 0.1 degrees rotation across the whole field of view. This calibration is also critical for the accurate measurement of local lattice parameters from HRTEM images.

Mist1 is necessary for the establishment of granule organization in serous exocrine cells of the gastrointestinal tract

Establishing a pool of granules at the luminal border is a key step during exocrine cell development in the pancreas and is necessary for efficient release of digestive enzymes through regulated exocytosis. Several proteins have been linked to maintaining granule organization, but it is unclear which regulatory mechanisms are necessary to establish organization. Based on temporal and spatial expression, the transcription factor Mist1 is an excellent candidate, and analysis of mice that do not express Mist1 (Mist1KO) reveal disrupted cell morphology in adult pancreatic acini. To address Mist1's role in establishing granule location, we have characterized the organization of pancreatic acini throughout development in Mist1KO mice. Using various histological approaches, we have determined that correct granule organization is never established in pancreatic acini of Mist1KO mice. Further examination indicates that this disruption in granule targeting may be the primary defect in Mist1KO mice as granule organization is affected in other serous exocrine cells that normally express Mist1. To identify a mechanistic link between granule targeting and the loss of Mist1 function, intercellular junctions and the expression of Rab3D were assessed. While both of these factors are affected in Mist1KO mice, these changes alone do not account for the disorganization observed in Mist1KO tissues. Therefore, we conclude that Mist1 is necessary for complete differentiation and maturation of serous exocrine cells through the combined regulation of several exocrine specific genes.

Body composition estimates from NHANES III bioelectrical impedance data

BACKGROUND

Body composition estimates for the US population are important in order to analyze trends in obesity, sarcopenia and other weight-related health conditions. National body composition estimates have not previously been available.

OBJECTIVE

To use transformed bioelectrical impedance analysis (BIA) data in sex-specific, multicomponent model-derived prediction formulae, to estimate total body water (TBW), fat-free mass (FFM), total body fat (TBF), and percentage body fat (%BF) using a nationally representative sample of the US population.

DESIGN

Anthropometric and BIA data were from the third National Health and Nutrition Examination Survey (NHANES III; 1988-1994). Sex-specific BIA prediction equations developed for this study were applied to the NHANES data, and mean values for TBW, FFM, TBF and %BF were estimated for selected age, sex and racial-ethnic groups.

RESULTS

Among the non-Hispanic white, non-Hispanic black, and Mexican-American participants aged 12-80 y examined in NHANES III, 15 912 had data available for weight, stature and BIA resistance measures. Males had higher mean TBW and FFM than did females, regardless of age or racial-ethnic status. Mean TBW and FFM increased from the adolescent years to mid-adulthood and declined in older adult age groups. Females had higher mean TBF and %BF estimates than males at each age group. Mean TBF also increased with older age groups to approximately 60 y of age after which it decreased.

CONCLUSIONS

These mean body composition estimates for TBW, FFM, TBF and %BF based upon NHANES III BIA data provide a descriptive reference for non-Hispanic whites, non-Hispanic blacks and Mexican Americans in the US population.

Tests of emigration in small mammals under experimental conditions

Holding animals in enclosures that block emigration causes demographic abnormalities called "fence effects." Experimenters have built exits that require animals to move through unfavorable conditions to leave enclosures. There are doubts about whether individuals that cross these challenging exits are true emigrants. We tested whether an exit that required house mice (Mus musculus) to swim through a water-filled trough was used only by mice triggered to emigrate from an experimental enclosure. Also, we examined the responses of mice to the availability of resources and the presence of conspecific adult animals in a small enclosure with an exit and in an enclosure made by joining two single enclosures. All mice left a barren enclosure within 12 h but no mice left during 7-day trials in a resource-rich enclosure during spring and summer. At the end of trials with repeated introduction of pairs of mice, about 85% of resident mice were the first mice added. Nearly all mice added later left the enclosure. A relatively constant number of mice became residents in small enclosures and about 2.3 times as many mice resided in double enclosures. Mice readily found and used exits when motivated to leave and did not accidentally pass through exits during routine exploration. Thus, mice that stayed in enclosures were not "fenced in" by the water-filled exit and exhibited residency as in nature. Tests of exits should give ecologists confidence that animals can display normal residency and emigration behaviors in experimental settings. The defense of resources by residents and the emigration of excess animals resulted in a consistent limit to the number of animals able to reside in enclosures.

A note on the emission of nitrogen oxides from silage in opened bunker silos

The evolution of NOx from grass and maize silages was measured using chemiluminescence in samples kept in airtight containers, in the silos and in a 750 kg mass removed to a mixer waggon. Measurements were made on the grass and maize silos in two consecutive years. The results show that there is continuous evolution of NOx after silos have been opened and that high concentrations persist in the mass which are rapidly released on agitation at the feed-out. The maximum recorded concentrations of NO and NO2 were 1985 and 152 ppbv respectively. These values are orders of magnitude greater than for rural background levels and exceed the maximum hourly exposure of 50 ppbv for NO2 recommended by the UK expert panel for quality standards.

Involvement of protein kinase C-delta in DNA damage-induced apoptosis

We have previously shown that the protein kinase C (PKC) signal transduction pathway regulates cell death by the DNA damaging agent cis-diamminedichloroplatinum(II) (cDDP). In the present study we have investigated how PKC influences the sequence of events that are triggered by cDDP-induced DNA damage. cDDP caused activation of caspases-8, -9, -3, -7 and cleavage of PKCdelta. Rottlerin, a selective inhibitor of novel PKCdelta, blocked activation of caspases, proteolytic activation of PKCdelta and cell death induced by cDDP. In contrast, Gö 6976, an inhibitor of conventional PKCalpha and betaI, did not prevent cDDP-induced caspase activation and cDDP cytotoxicity. In HeLa cells, PKCdelta was distributed both in the cytosol and heavy membrane (HM) fraction containing mitochondria. While caspase-8 was primarily cytosolic, a small amount of caspases-9, -7 and -3 could be detected in the HM fraction. cDDP caused a time-dependent increase in Cytochrome c release from the mitochondria and processing of both cytosolic and membrane-associated caspases, as well as proteolytic cleavage of PKCdelta. Rottlerin attenuated late but not early release of Cytochrome c by cDDP. It, however, inhibited activation of caspases and proteolytic cleavage of PKCdelta in both cytosolic and HM fractions. The antiapoptotic effect of rottlerin was evident when it was added together with or following cDDP addition but not when added after cDDP was removed from the medium. Thus, the PKCdelta inhibitor acts at an early stage of the cDDP-induced cell death pathway that precedes caspase activation.

Replication of Chilo iridescent virus in the cotton boll weevil, Anthonomus grandis, and development of an infectivity assay

The boll weevil, Anthonomus grandis Boheman, is a devastating pest of cotton. Chemical pesticides are problematic due to relative lack of target specificity and resistance. Microbial pesticides may provide viable alternatives because of their narrow host range. Chilo iridescent virus (CIV) is the type species for genus Iridovirus, family Iridoviridae: large, icosahedral cytoplasmic viruses containing a double-stranded DNA genome. Earlier work suggested that CIV replicated in the boll weevil; however, efficiency or production of infectious virus was not established. We showed that CIV undergoes a productive cycle in A. grandis. CIV DNA levels in boll weevil pupae increased significantly from 0 to 3 days post infection. Moreover, virogenic stromata and complete virus particles were observed in the cytoplasm by 7 days. An endpoint dilution assay using viral DNA replication as indicator suggested a 10(5)-fold increase in infectious virus titer over 7 days. This is the first such demonstration in larval infections with genus Iridovirus. Our study establishes that CIV undergoes a productive cycle in the boll weevil and provides an important and useful model system for replication at the organismal level. These results have important implications for the potential of CIV and its components in boll weevil control.

Prevalence of overweight in US children: comparison of US growth charts from the Centers for Disease Control and Prevention with other reference values for body mass index

BACKGROUND

Several different sets of reference body mass index (BMI) values are available to define overweight in children.

OBJECTIVE

The objective of this study was to compare the prevalence of overweight in US children calculated with 3 sets of reference BMI values: the revised growth charts of the Centers for Disease Control and Prevention (CDC-US growth charts), international standards proposed by Cole et al, and values developed by Must et al.

DESIGN

Data for children and adolescents came from cross-sectional nationally representative US surveys: cycles II and III of the National Health Examination Survey (1963-1965 and 1966-1970) and the first, second, and third National Health and Nutrition Examination Surveys: NHANES I (1971-1974), II (1976-1980), and III (1988-1994). The reference values of Cole et al equivalent to a BMI of 25 were compared with the 85th percentiles from the other 2 methods; the values equivalent to a BMI of 30 were compared with the 95th percentiles.

RESULTS

The 3 methods gave similar but not identical results. The reference values of Cole et al gave lower estimates than did the CDC-US growth charts for young children but higher estimates for older children. The reference values of Must et al gave much higher prevalences for younger girls than did the other 2 methods.

CONCLUSIONS

Differences between methods were related to differences in data sets, smoothing methods, and theoretical approaches. All 3 methods are based on statistical criteria and incorporate arbitrary assumptions. These methods should be used cautiously, with awareness of the possible limitations.

Functional genomic, biochemical, and genetic characterization of the Salmonella pduO gene, an ATP:cob(I)alamin adenosyltransferase gene

Salmonella enterica degrades 1,2-propanediol by a pathway dependent on coenzyme B12 (adenosylcobalamin [AdoCb1]). Previous studies showed that 1,2-propanediol utilization (pdu) genes include those for the conversion of inactive cobalamins, such as vitamin B12, to AdoCbl. However, the specific genes involved were not identified. Here we show that the pduO gene encodes a protein with ATP:cob(I)alamin adenosyltransferase activity. The main role of this protein is apparently the conversion of inactive cobalamins to AdoCbl for 1,2-propanediol degradation. Genetic tests showed that the function of the pduO gene was partially replaced by the cobA gene (a known ATP:corrinoid adenosyltransferase) but that optimal growth of S. enterica on 1,2-propanediol required a functional pduO gene. Growth studies showed that cobA pduO double mutants were unable to grow on 1,2-propanediol minimal medium supplemented with vitamin B(12) but were capable of growth on similar medium supplemented with AdoCbl. The pduO gene was cloned into a T7 expression vector. The PduO protein was overexpressed, partially purified, and, using an improved assay procedure, shown to have cob(I)alamin adenosyltransferase activity. Analysis of the genomic context of genes encoding PduO and related proteins indicated that particular adenosyltransferases tend to be specialized for particular AdoCbl-dependent enzymes or for the de novo synthesis of AdoCbl. Such analyses also indicated that PduO is a bifunctional enzyme. The possibility that genes of unknown function proximal to adenosyltransferase homologues represent previously unidentified AdoCbl-dependent enzymes is discussed.

Periodontal disease estimates in NHANES III: clinical measurement and complex sample design issues

OBJECTIVE

This paper evaluates the possibility that examiner bias or other factors contributed to an observed decline in pocket depth and gingivitis between the two three-year sequential periods of time (or phases) covered by the Third National Health and Nutrition Examination Survey (NHANES III).

METHODS

Prevalences of periodontal conditions were analyzed using data from two sets of repeat oral health examinations by examining dentists of NHANES III sample persons. The first set includes sample persons who were examined twice by the same examining dentist at an interval of one to six weeks. The second set includes sample persons who were assessed on the same day by both an examining dentist and a reference dentist. Other possible sources of error also were evaluated.

RESULTS

Overall kappa statistics measuring agreement between or within dental examiners were within the range observed for other periodontal disease surveys. While differences were found among dentists in the prevalence of pocket depth of 4 mm or more, for each group of sample persons assessed by a reference examiner-examining dentist pair, the reference examiner's periodontal measurements closely corresponded to measurements made by the examining dentists.

CONCLUSIONS

Differences between dental examiners in prevalences of periodontal conditions may be due in part to the fact that examinees were not randomly assigned to examiners. As a result, the sample persons examined by each dentist may not have been alike in characteristics thought to affect periodontal disease status. These findings suggest that the observed declines in periodontal health status between phases is not due to examiner bias. This unexplained decline may be the result of sampling variation. It is recommended that combined six-year survey results be presented whenever possible.

Comprehensive analysis of the acute toxicities induced by systemic administration of cationic lipid:plasmid DNA complexes in mice

A major limitation associated with systemic administration of cationic lipid:plasmid DNA (pDNA) complexes is the vector toxicity at the doses necessary to produce therapeutically relevant levels of transgene expression. Systematic evaluation of these toxicities has revealed that mice injected intravenously with cationic lipid:pDNA complexes develop significant, dose-dependent hematologic and serologic changes typified by profound leukopenia, thrombocytopenia, and elevated levels of serum transaminases indicative of hepatocellular necrosis. Vector administration also induced a potent inflammatory response characterized by complement activation and the induction of the cytokines IFN-gamma, TNF-alpha, IL-6, and IL-12. These toxicities were found to be transient, resolving with different kinetics to pretreatment levels by 14 days posttreatment. The toxic syndrome observed was independent of the cationic lipid:pDNA ratio, the cationic lipid species, and the level of transgene expression attained. Mechanistic studies determined that neither the complement cascade nor TNF-alpha were key mediators in the development of these characteristic toxicities. Administration of equivalent doses of the individual vector components revealed that cationic liposomes or pDNA alone did not generate the toxic responses observed with cationic lipid:pDNA complexes. Only moderate leukopenia was associated with administration of cationic liposomes or pDNA alone, while only mild thrombocytopenia was noted in pDNA-treated animals. These results establish a panel of objective parameters that can be used to quantify the acute toxicities resulting from systemic administration of cationic lipid:pDNA complexes, which in turn provides a means to compare the therapeutic indices of these vectors.

Serum total homocysteine concentration is related to self-reported heart attack or stroke history among men and women in the NHANES III

High circulating total homocysteine (tHcy) concentration, which is influenced by folate and vitamin B-12 status, is a suspected cause of cardiovascular events. This relation has been investigated in both case-control and prospective studies but has not been evaluated for different sex x age subgroups of the general U.S. population. We used data on adult (i.e., aged > or =40 y) male (n = 1097) and female (n = 1107) participants in the third National Health and Nutrition Examination Survey, excluding diabetics and those supplemented with estrogen, vitamins or minerals, to evaluate the association between serum tHcy concentration and self-report of heart attack or stroke. After adjustment for age, race-ethnicity, smoking, blood pressure, blood pressure medication, body mass index and serum concentrations of creatinine and cholesterol, past events were reported 2.4 (95% confidence interval 1.0-5.5) times as often by men with tHcy concentration of >12 micromol/L as by men with lower values. The odds ratio for women was 2.6 (95% confidence interval 1.1-6.6) after adjustment for the same factors plus menopausal status. A stronger relation in men aged < or =60 y compared with older men may help reconcile conflicting results of earlier studies.

Analysis of factors influencing the comparison of homocysteine values between the Third National Health and Nutrition Examination Survey (NHANES) and NHANES 1999+

Two important changes occurred in the time between the Third National Health and Nutrition Examination Survey (NHANES III) (1991-1994) and the later survey (NHANES 1999+) regarding total homocysteine (tHcy), i.e., a change in matrix from serum to plasma and a change in analytical methods. The goals of this study were to determine the magnitude of potential differences between plasma and serum with regard to tHcy concentrations, and between the two analytical methods used in these surveys. Optimally prepared plasma, serum allowed to clot for 30 and 60 min at room temperature and serum allowed to clot for 30 and 60 min and subjected to four freeze-thaw cycles, prepared from blood samples collected from 30 healthy people, were analyzed by both methods. Serum samples had significantly higher tHcy concentrations than plasma samples, and the difference increased with longer clotting time. Freeze-thaw cycles had little or no effect on the variability or bias in the serum sample results. The tHcy results produced by the two analytical methods were significantly different, but consistent across sample types. On average, the results of the method used in NHANES III were lower by 0.64 micromol/L; however, the relative bias varied with tHcy concentration. The tHcy results determined in surplus serum from NHANES III overestimated tHcy concentrations by approximately 10% compared with optimally prepared plasma. The average method bias was 6% between the two analytical methods. On the basis of changes in matrix and methodology, direct comparison of tHcy results between the two surveys is inappropriate.

Serum ferritin and death from all causes and cardiovascular disease: the NHANES II Mortality Study. National Health and Nutrition Examination Study

PURPOSE

The purpose of this study was to assess the association between serum ferritin and death from all causes, cardiovascular diseases (CVD), CHD and myocardial infarction (MI). Positive body iron stores have been proposed as a risk factor for coronary heart disease (CHD). While most epidemiologic studies using serum ferritin and other measures of body iron stores have not found an association between iron and heart disease risk, the hypothesis remains controversial. As a result, we examined the relationship of serum ferritin, the principle blood measure of body iron stores, to risk of death in a cohort with a standardized exam and long follow-up.

METHODS

The baseline data for this prospective cohort study were collected in 1976-1980 as part of the second National Health and Nutrition Examination Study (NHANES II) with mortality follow-up using the National Death Index (NDI) through December 31, 1992. The analytic sample (n = 1604) consisted of 128 black men, 658 white men, 100 black women and 718 white women 45-74 years of age at baseline who, based on self-reported data, were free of coronary heart disease at baseline and had no missing data. The main outcome measures were the relative risk of death for persons with serum ferritin levels: <50 microg/L; or 100-199 microg/L; or > or =200 microg/L was compared to persons with serum ferritin levels of 50-99 microg/L adjusted for possible confounding using the Cox proportional hazards model.

RESULTS

Most of the deaths were among white men (n = 254) and women (n = 168). There were relatively few deaths among black men (n = 50) and too few in women (n = 23) to reliably model. The largest number of CVD (n = 119), CHD (n = 82), and MI (n = 49) deaths were in white men while there were 69 CVD, 45 CHD and 13 MI deaths in white women. Black men with a serum ferritin level of <50 microg/L had a significantly higher adjusted risk of death from all causes (RR = 3.1 with 95% confidence limits of 1.5-6.5). There were no other statistically significant associations for all causes mortality for the other three race/sex groups. Additionally, there were no statistically significant associations between serum ferritin and any of the cardiovascular endpoints for any of the groups. There was an apparent but nonsignificant u-shaped association between serum ferritin and all causes mortality in black men and between serum ferritin and CVD death in white women. However, in both cases very wide confidence limits preclude further interpretation.

CONCLUSIONS

Overall, the results do not support the hypothesis that positive body iron stores, as measured by serum ferritin, are associated with an increased risk of CVD, CHD or MI death or between serum ferritin and all causes mortality. Most of the research to date with serum ferritin has been conducted in European men or in European American men. Our results are consistent with the primarily negative results for that race/sex group. More research is needed in women and minority groups, including an explanation of why such an association would exist in these groups but not in white men before an association can be established in them.

CDC growth charts: United States

OBJECTIVES

This report presents the revised growth charts for the United States. It summarizes the history of the 1977 National Center for Health Statistics (NCHS) growth charts, reasons for the revision, data sources and statistical procedures used, and major features of the revised charts.

METHODS

Data from five national health examination surveys collected from 1963 to 1994 and five supplementary data sources were combined to establish an analytic growth chart data set. A variety of statistical procedures were used to produce smoothed percentile curves for infants (from birth to 36 months) and older children (from 2 to 20 years), using a two-stage approach. Initial curve smoothing for selected major percentiles was accomplished with various parametric and nonparametric procedures. In the second stage, a normalization procedure was used to generate z-scores that closely match the smoothed percentile curves.

RESULTS

The 14 NCHS growth charts were revised and new body mass index-for-age (BMI-for-age) charts were created for boys and girls (http://www.cdc.gov/growthcharts). The growth percentile curves for infants and children are based primarily on national survey data. Use of national data ensures a smooth transition from the charts for infants to those for older children. These data better represent the racial/ethnic diversity and the size and growth patterns of combined breast- and formula-fed infants in the United States. New features include addition of the 3rd and 97th percentiles for all charts and extension of all charts for children and adolescents to age 20 years.

CONCLUSION

Created with improved data and statistical curve smoothing procedures, the United States growth charts represent an enhanced instrument to evaluate the size and growth of infants and children.

Hippocampal volume and everyday memory in children of very low birth weight

Children born preterm and of very low birth weight have an increased incidence of learning difficulties, but little is known about the specific nature of their cognitive deficits and the underlying neuropathology. We hypothesized that their vulnerability to hypoxic, metabolic, and nutritional insults would lead to reduced hippocampal volumes and to deficits in memory because of the role of the hippocampus in this domain of cognition. Neuropsychological and magnetic resonance imaging methods were used to investigate this hypothesis in adolescents born preterm (< or = 30 wk gestation, n = 11) or full-term (n = 8). The preterm group had significantly smaller hippocampal volumes bilaterally, despite equivalent head size, and showed specific deficits in certain aspects of everyday memory, both on objective testing and as indicated by parental questionnaires. The preterm group also had a specific deficit in numeracy. The reduced hippocampal volumes and deficits in everyday memory have previously been unrecognized, but their prevalence in a group of neurologically normal children is striking.

Diffusion and perfusion magnetic resonance imaging in childhood stroke

Two magnetic resonance imaging techniques, diffusion and perfusion imaging, are being used increasingly for evaluation of pathophysiology of stroke. This article introduces these techniques and reports some initial studies using these approaches, together with conventional T2-weighted magnetic resonance imaging, for investigation of childhood stroke. It is shown that the combination of T2-weighted and diffusion images can provide information about the timing of stroke events in childhood, and perfusion imaging can detect abnormalities not visible by other magnetic resonance imaging techniques. These magnetic resonance methods therefore should play an important role in investigation of children with stroke and could be of particular value in studies of at-risk populations of children such as those with sickle cell disease.

Internal structure and early thermal evolution of Mars from Mars Global Surveyor topography and gravity

Topography and gravity measured by the Mars Global Surveyor have enabled determination of the global crust and upper mantle structure of Mars. The planet displays two distinct crustal zones that do not correlate globally with the geologic dichotomy: a region of crust that thins progressively from south to north and encompasses much of the southern highlands and Tharsis province and a region of approximately uniform crustal thickness that includes the northern lowlands and Arabia Terra. The strength of the lithosphere beneath the ancient southern highlands suggests that the northern hemisphere was a locus of high heat flow early in martian history. The thickness of the elastic lithosphere increases with time of loading in the northern plains and Tharsis. The northern lowlands contain structures interpreted as large buried channels that are consistent with northward transport of water and sediment to the lowlands before the end of northern hemisphere resurfacing.

Warfarin-5-FU interaction--a consecutive case series

Five patients from a single institution received concomitant warfarin and 5-fluorouracil (5-FU) during a 3-year period. The mean weekly warfarin dose before starting chemotherapy was 40.66 mg and during chemotherapy it was 24 mg (p=0.0026). All patients required a warfarin dosage reduction (range 18-74%, mean 44%). Two patients were hospitalized, one with a major retroperitoneal bleed, the other for fresh-frozen plasma administration and observation. Maximum international normalized ratios (INRs) ranged from 3.66-23.7. This series confirms a common, clinically significant interaction between warfarin and 5-FU. An interaction between capecitabine, the orally available prodrug of 5-FU, and warfarin also has been reported. We recommend weekly monitoring of prothrombin time and INR for all patients receiving concomitant warfarin and 5-FU or capecitabine.