Risk Factors for Foster Care Placement in Patients with Bronchopulmonary Dysplasia

OBJECTIVE

 Bronchopulmonary dysplasia (BPD) is a major cause of morbidity in neonates and can be associated with long hospitalization and high health care utilization. This extremely stressful situation can be difficult for many families and caregivers. The high-risk situation combined with increased medical complexity can result in involvement of Department of Child Services (DCS) and even foster care placement. This study seeks to define risk factors for DCS involvement and foster care placement in children with BPD.

STUDY DESIGN

 A retrospective study of children born at less than 32 weeks of gestation born between 2010 and 2016, on oxygen at 28 days of life and discharged home from a tertiary care center.

RESULTS

 A total of 246 patients were identified. DCS was involved in 49 patients with 13 requiring foster care placement. The most common correlated risk factors that were identified for DCS involvement were maternal THC (tetrahydrocannabinol) positivity, hospital policy violations, maternal mental health diagnosis, and home insecurity. Home insecurity (p < 0.005) and amphetamine use (p < 0.005) were associated with foster care placement.

CONCLUSION

 There are numerous risk factors for both DCS and foster care placement. The identification of these risk factors is important to help establish services to help families and identify potential biases to avoid.

KEY POINTS

· There were both substance-related and non-substance-related risk factors for DCS involvement.. · Home insecurity and maternal amphetamine use were risk factors associated with foster care placement.. · This study fills the knowledge gap of risk factors for DCS and foster care placement in BPD..

Dual Nanoparticle Conjugates for Highly Sensitive and Versatile Sensing Using 19 F Magnetic Resonance Imaging

Fluorine magnetic resonance imaging (19 F MRI) has emerged as an attractive alternative to conventional 1 H MRI due to enhanced specificity deriving from negligible background signal in this modality. We report a dual nanoparticle conjugate (DNC) platform as an aptamer-based sensor for use in 19 F MRI. DNC consists of core-shell nanoparticles with a liquid perfluorocarbon core and a mesoporous silica shell (19 F-MSNs), which give a robust 19 F MR signal, and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic quenchers. Due to the strong magnetic quenching effects of SPIONs, this platform is uniquely sensitive and functions with a low concentration of SPIONs (4 equivalents) relative to 19 F-MSNs. The probe functions as a "turn-on" sensor using target-induced dissociation of DNA aptamers. The thrombin binding aptamer was incorporated as a proof-of-concept (DNCThr ), and we demonstrate a significant increase in 19 F MR signal intensity when DNCThr is incubated with human α-thrombin. This proof-of-concept probe is highly versatile and can be adapted to sense ATP and kanamycin as well. Importantly, DNCThr generates a robust 19 F MRI "hot-spot" signal in response to thrombin in live mice, establishing this platform as a practical, versatile, and biologically relevant molecular imaging probe.

Implication of current ASE/EACVI left ventricular diastolic function classification in predicting 2-year MACE in asymptomatic patients with diabetes and hypertension

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate diastolic function based on the current ASE/EACVI guidelines. The implication of current diastolic function classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based diastolic function classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LV diastolic function. The 2016 ASE/EACVI guidelines were applied to classify diastolic function. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 ± 7.45 years; mean duration of type 2 diabetes was 10.5 ± 5.41 years. 80 (72.1%) patients were classified as having normal diastolic function (nDF); 24 (21.6%) patients were classified as indeterminate diastolic function (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72 ± 23.28g/m2 vs 116.62 ± 24.66g/m2 in iDF vs 102.50 ± 22.89g/m2 in nDF, p = 0.003); higher left atrial volume index (LAVI) (mean 41.24 ± 10.28ml/m2 vs 30.55 ± 10.07ml/m2 in iDF vs 25.75 ± 6.30ml/m2 in nDF, p &lt; 0.001); lower lateral e’ velocity (mean 6.35 ± 2.05cm/s vs 7.37 ± 1.73cm/s in iDF vs 8.59 ± 2.13cm/s in nDF, p = 0.003); higher septal E/e’ ratio (mean 14.89 ± 3.29 vs 12.16 ± 3.99 in iDF vs 9.99 ± 2.35 in nDF, p = 0.001); higher average septal-lateral E/e’ ratio (mean 14.22 ± 3.77 vs 11.34 ± 3.74 in iDF vs 9.04 ± 2.10 in nDF, p &lt; 0.001).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both indeterminate diastolic function[hazards ratio (HR) 3.80, p = 0.023] and LVDD (HR 37.78, p = 0.002). BMI (HR 1.25, p = 0.004), and systolic blood pressure (HR 1.07, p &lt; 0.001) were found to be associated with 2-year MACE.

Conclusions

LVDD and indeterminate diastolic function were correlated with increased MACE at 2 years. BMI and systolic blood pressure were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Implication of Current ASE/EACVI Left Ventricular Diastolic Function Classification in Predicting 2-Year MACE in Asymptomatic Patients with Diabetes and Hypertension

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate DF based on the current ASE/EACVI guidelines. The implication of current DF classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based DF classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. The 2016 ASE/EACVI guidelines were applied to classify DF. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of DM was 10.5 (5.41). 80 (72.1%) patients were classified as having normal DF (nDF); 24 (21.6%) patients were classified as indeterminate DF (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72±23.28g/m2 vs 116.62±24.66g/m2 in iDF vs 102.50±22.89g/m2 in nDF); higher left atrial volume index (LAVI) (mean 41.24±10.28ml/m2 vs 30.55±10.07ml/m2 in iDF vs 25.75±6.30ml/m2 in nDF); lower lateral e' velocity (mean 6.35±2.05cm/s vs 7.37±1.73cm/s in iDF vs 8.59±2.13cm/s in nDF); higher septal E/e' ratio (mean 14.89±3.29 vs 12.16±3.99 in iDF vs 9.99±2.35 in nDF); higher average septal-lateral E/e' ratio (mean 14.22±3.77 vs 11.34±3.74 in iDF vs 9.04±2.10 in nDF).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both iDF [odds ratio (OR) 3.80, 95% CI 0.87–16.54, p=0.075] and LVDD [OR 7.60, 95% CI 1.11–52.02, p=0.039]. LVMI (OR 1.027, 95% CI 1.004– 1.051, p=0.023), LAVI (OR 1.092, 95% CI 1.017–1.172), and average septal-lateral E/e' ratio (OR 1.276, 95% CI 1.047–1.557, p=0.016) significantly correlated with 2-year MACE.

Conclusions

LVDD is correlated with increased MACE at 2 years. LVMI, LAVI and average septal-lateral E/e' ratio were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Modulating extraction and retention of fluorinated β-diketonate metal complexes in perfluorocarbons through the use of non-fluorinated neutral ligands

Extraction of metal ions into perfluorocarbon solvent with a fluorinated acac ligand is described as well as synergistic extraction with neutral nitrogen donor ligands. Applications include catalysis, nuclear fuels reprocessing, and medical imaging.

Disabling working environments and mental health: A commentary

Employment is a fundamental Social Determinant of Health known to have large impacts on mental health and other health outcomes. Across many countries of the world, people with disabilities are much more likely to be unemployed and looking for work than those without disabilities. The deprivation of employment opportunities is likely to have notable impacts on the health of people with disabilities. In this commentary, we outline the concept of "disabling working environments," which are defined as the range of experiences that affect the likelihood of people with disabilities in obtaining and maintaining quality employment which may then affect a disabled person's health. Disabling working environments are comprised of the following three mutually reinforcing components: 1) Differential selection into work; 2) Selection into certain types of jobs and exposure to poor psychosocial working environments when in employment, and; 3) Differential selection out of work (e.g., leaving employment at an earlier age than those who do not have a disability). We argue that policy and intervention design should consider the life course effects of employment on the mental health of people with disabilities.

Anisotropic lanthanide-based nano-clusters for imaging applications

We have developed a new class of lanthanide nano-clusters that self-assemble using flexible Schiff base ligands. Cd-Ln and Ni-Ln clusters, [Ln8Cd24(L1)12(OAc)39Cl7(OH)2] (Ln = Nd, Eu), [Eu8Cd24(L1)12(OAc)44], [Ln8Cd24(L2)12(OAc)44] (Ln = Nd, Yb, Sm) and [Nd2Ni4(L3)2(acac)6(NO3)2(OH)2], were constructed using different types of flexible Schiff base ligands. These molecular nano-clusters exhibit anisotropic architectures that differ considerably depending upon the presence of Cd (nano-drum) or Ni (square-like nano-cluster). Structural characterization of the self-assembled particles has been undertaken using crystallography, transmission electron microscopy and small-angle X-ray scattering. Comparison of the metric dimensions of the nano-drums shows a consistency of size using these techniques, suggesting that these molecules may share similar structural features in both solid and solution states. Photophysical properties were studied by excitation of the ligand-centered absorption bands in the solid state and in solution, and using confocal microscopy of microspheres loaded with the compounds. The emissive properties of these compounds vary depending upon the combination of lanthanide and Cd or Ni present in these clusters. The results provide new insights into the construction of novel high-nuclearity nano-clusters and offer a promising foundation for the development of new functional nanomaterials.

Self-assembly of high-nuclearity lanthanide-based nanoclusters for potential bioimaging applications

Two series of Cd-Ln and Ni-Ln clusters [Ln8Cd24L12(OAc)44(48)Cl4(0)] and [Ln8Ni6L6(OAc)24(EtOH)6(H2O)2] were constructed using a flexible ligand. The Cd-Ln clusters exhibit interesting nano-drum-like structures which allows direct visualization by TEM. Luminex MicroPlex Microspheres loaded with the Cd-Sm cluster were visualized using epifluorescence microscopy. Cytotoxicity studies on A549 and AGS cancer cell lines showed that the materials have mild to moderate cytotoxicity.

Nafcillin Resistant Staphylococcus Aureus A Possible Community Origin

An increased incidence in nafcillin (semisynthetic penicillins) resistantStaphylococcus aureus(SR-SA), which peaked in January 1980, was noted in Columbus Children's Hospital (CCH), Columbus, Ohio. To investigate the source of this outbreak, we reviewed the susceptibility patterns ofS. aureusstrains isolated at CCH for a 12-month period (July 1979 to June 1980). A total of 773 isolates from 706 patients were investigated with a total of 40 patients colonized or infected with SR-SA, approximately 25% of which were diagnosed in the ambulatory clinics. These patients did not have any apparent previous contact with the inpatient unit or inpatient personnel. Eight nosocomial infections were also uncovered. The first appeared in December 1979. Our studies suggested that some SR-SA isolates may have originated in the community and these organisms may not be exclusive to the hospital environment, as was felt to be the case previously. We also determined that the baseline incidence for our hospital of SR-SA was approximately 2% of total S.aureusisolates. Only 35% of the SR-SA demonstrated resistance to multiple antibiotics. This report indicates that community and nosocomial 5.aureusisolates should be monitored for nafcillin resistance. Vancomycin susceptibility should be tested on all isolates and reported for SR-SA in life-threatening infections.

The role of body-on-a-chip devices in drug and toxicity studies

High-quality, in vitro screening tools are essential in identifying promising compounds during drug development. Tests with currently used cell-based assays provide an indication of a compound's potential therapeutic benefits to the target tissue, but not to the whole body. Data obtained with animal models often cannot be extrapolated to humans. Multicompartment microfluidic-based devices, particularly those that are physical representations of physiologically based pharmacokinetic (PBPK) models, may contribute to improving the drug development process. These scaled-down devices, termed micro cell culture analogs (μCCAs) or body-on-a-chip devices, can simulate multitissue interactions under near-physiological fluid flow conditions and with realistic tissue-to-tissue size ratios. Because the device can be used with both animal and human cells, it can facilitate cross-species extrapolation. Used in conjunction with PBPK models, the devices permit an estimation of effective concentrations that can be used for studies with animal models or predict the human response. The devices also provide a means for relatively high-throughput screening of drug combinations and, when utilized with a patient's tissue sample, an opportunity for individualized medicine. Here we review efforts made toward the development of microfabricated cell culture systems and give examples that demonstrate their potential use in drug development, such as identifying synergistic drug interactions as well as simulating multiorgan metabolic interactions. In addition to their use in drug development, the devices also can be used to estimate the toxicity of chemicals as occupational hazards and environmental contaminants.

Sensory afferent and hypoxia-mediated activation of nucleus tractus solitarius neurons that project to the rostral ventrolateral medulla

The nucleus tractus solitarius (nTS) of the brainstem receives sensory afferent inputs, processes that information, and sends projections to a variety of brain regions responsible for influencing autonomic and respiratory output. The nTS sends direct projections to the rostral ventrolateral medulla (RVLM), an area important for cardiorespiratory reflexes and homeostasis. Since the net reflex effect of nTS processing ultimately depends on the properties of output neurons, we determined the characteristics of these RVLM-projecting nTS neurons using electrophysiological and immunohistochemical techniques. RVLM-projecting nTS neurons were identified by retrograde tracers. Patch clamp analysis in the horizontal brainstem nTS slice demonstrated that RVLM-projecting nTS cells exhibit constant latency solitary tract evoked excitatory postsynaptic currents (EPSCs), suggesting they receive strong monosynaptic contacts from visceral afferents. Three distinct patterns of action potential firing, associated with different underlying potassium currents, were observed in RVLM-projecting cells. Following activation of the chemoreflex in conscious animals by 3 h of acute hypoxia, 11.2+/-1.9% of the RVLM-projecting nTS neurons were activated, as indicated by positive Fos-immunoreactivity. Very few RVLM-projecting nTS cells were catecholaminergic. Taken together, these data suggest that RVLM projecting nTS neurons receive strong monosynaptic inputs from sensory afferents and a subpopulation participates in the chemoreflex pathway.

Three-dimensional integrated microfluidic architectures enabled through electrically switchable nanocapillary array membranes

The extension of microfluidic devices to three dimensions requires innovative methods to interface fluidic layers. Externally controllable interconnects employing nanocapillary array membranes (NCAMs) have been exploited to produce hybrid three-dimensional fluidic architectures capable of performing linked sequential chemical manipulations of great power and utility. Because the solution Debye length, kappa(-1), is of the order of the channel diameter, a, in the nanopores, fluidic transfer is controlled through applied bias, polarity and density of the immobile nanopore surface charge, solution ionic strength and the impedance of the nanopore relative to the microfluidic channels. Analyte transport between vertically separated microchannels can be saturated at two stable transfer levels, corresponding to reverse and forward bias. These NCAM-mediated integrated microfluidic architectures have been used to achieve highly reproducible and tunable injections down to attoliter volumes, sample stacking for preconcentration, preparative analyte band collection from an electrophoretic separation, and an actively-tunable size-dependent transport in hybrid structures with grafted polymers displaying thermally-regulated swelling behavior. The synthetic elaboration of the nanopore interior has also been used to great effect to realize molecular separations of high efficiency. All of these manipulations depend critically on the transport properties of individual nanocapillaries, and the study of transport in single nanopores has recently attracted significant attention. Both computation and experimental studies have utilized single nanopores as test beds to understand the fundamental chemical and physical properties of chemistry and fluid flow at nanometer length scales.

Tracing the source of 3,3'-dichlorobiphenyl found in samples collected in and around Halifax Harbour

3,3'-dichlorobiphenyl (IUPAC No. 11), a chlorobiphenyl (CB) that is not generally analysed in environmental studies of CBs, is found, sometimes at high concentrations, in water, suspended particulate material, biota and sediments from Halifax Harbour, NS, Canada. The results presented demonstrate the need for investigations of non-Aroclor CBs like CB 11. Not only can they have rather elevated environmental concentrations like those reported here for CB 11, but they also can be members of the more toxic non-ortho class of CBs and thus important from a toxicity standpoint. The focus of this paper was to investigate the possible sources of CB 11, a trace constituent of commercial mixtures, but dominant in various environmental compartments of Halifax Harbour.

Population structure of Atlantic salmon (Salmo salarL.): a range-wide perspective from microsatellite DNA variation

Atlantic salmon (n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south-central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5-37/locus) range-wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum-likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available.

Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): conservation implications of range discontinuity

A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona, as represented by the four species surveyed in this study, may not be monophyletic.

Treating urinary incontinence in the elderly population: accepting the challenge

Health care professionals who choose to treat the elderly have a responsibility to be knowledgeable about incontinence. The elderly present challenging and complex problems that may require a collaborative approach from a dedicated team, to include family members, home health nurses, continence nurses, physical therapists, as well as primary care physicians, geriatricians, urologists, and gynecologists. The elderly patient should be reminded that they are a member of that team and their commitment and participation will facilitate successful outcomes.

Estimating analytical variances in measurement of polycyclic aromatic hydrocarbons and application to monitoring contaminants in American lobster (Homarus americanus)

A method is presented for estimating replicate polycyclic aromatic hydrocarbon (PAH) concentrations in American lobster (Homarus americanus) digestive gland tissue based on recoveries of added perdeuterated surrogates from a single satisfactory analysis. PAH concentrations demonstrated a large interanimal variance, even in specimens captured at the same time in the same place. Principal component analysis showed that the variability of the total system of biological variables (carapace length, lobster weight, and digestive gland weight) could be adequately summarized by the first principal component alone in each data set. Ranks provide ordered classification of individuals, allowing data analysis by statistical methods for continuous variables (i.e., analysis of variance). PAH concentrations in individual lobsters were generally highly sensitive to animal size, sex, and fishing area. Efficient monitoring would result from analyzing individual animals of a single sex from a study area, using as small a geographical study area as possible, measuring a single biological variable, and using individual specimens of as narrow a size range as possible.

Rapid screening of fish tissue for polychlorinated dibenzo-p-dioxins and dibenzofurans

A rapid, simple method for screening polychlorinated dibenzo-p-dioxin and dibenzofuran classes in shellfish tissue at pg g-1 wet mass concentrations is described. The method does not require a clean room facility and is based on saponification followed by extraction into hexane, clean-up using gel-permeation chromatography and sulfuric acid treatment, and measurement using capillary gas chromatography-low resolution mass spectrometry with selected ion monitoring. Selected ion monitoring using multiple ions eliminates interferences not removed by clean-up or chromatography. The detector response factor is constant for isomers within a class, e.g., tetrachlorodibenzo-p-dioxin isomers gave a mean response of 0.977 +/- 0.075 area counts fg-1, but varied significantly between classes. Thus one isomer serves as a 'standard' for all members of its class. Recoveries of added polychlorinated dibenzo-p-dioxins and dibenzofurans (20-500 pg g-1 wet mass) averaged 95.6 +/- 6.9 and 99.0 +/- 5.7%, respectively. The limits of detection (five times the noise level) are 20 pg g-1 tetrachlorodibenzo-p-dioxins and dibenzofurans, 20 pg g-1 pentachlorodibenzo-p-dioxins and dibenzofurans, 40 pg g-1 hexachlorodibenzo-p-dioxins and dibenzofurans, 40 pg g-1 heptachlorodibenzo-p-dioxins and dibenzofurans, and 100 pg g-1 octachlorodibenzo-p-dioxin and dibenzofuran. Above the limits of detection, the method gave results for polychlorinated dibenzo-p-dioxin and dibenzofuran classes in shellfish tissue comparable to those obtained by gas chromatography-high resolution mass spectrometry.

The influence of early nutrition and environmental rearing on brain growth and behaviour

Preweaning malnutrition permanently reduced brain size and cellular content but in spite of changes in the adrenocotical stress response no learning deficit was observed. Differential rearing environments did not influence the effects of malnutrition.

Hormonal regulation of fetal brain cell proliferation: presence in serum of a trophin responsive to pituitary growth hormone stimulation

Previous studies led us to hypothesize that brain growth was regulated by a growth hormone-dependent brain trophin. An in vitro bioassay system to assess this proposal was developed. Serum was shown to stimulate the uptake of tritiated thymidine into fetal brain cell DNA. This action could not be attributed to any nutrient contribution but was due to a non-dialyzable, heat-stable serum growth factor. The levels of the growth factor in serum were reduced after pituitary removal. When added in physiological concentration, growth hormone, prolactin, placental lactogen, insulin, nerve growth factor, thyroid and steroid hormones failed to stimulate the action of serum or to act synergistically with a serum component to stimulate DNA synthesis. Thyroxine, estradiol-17beta, and corticosterone inhibited serum activity. Administration of growth hormone to hypophysectomized rats restored serum levels to normal demonstrating that the serum growth factors was a mediating trophin responsive to pituitary growth hormone stimulation. The relationship of the brain trophin to other serum growth factors and its specificity of action remain to be defined. The present findings were in accordance with in vivo studies of hormonal influence on brain growth and support the proposal that fetal brain cell proliferation is stimulated by a serum trophin responsive to pituitary growth hormone.

The influence of protein restriction imposed at various stages of pregnancy on fetal and placental development

The effect of protein restriction on fetal and placental growth was investigated. Pregnant rats were maintained on an isocaloric diet containing either 23% or 5% protein. The diet was imposed either from days 1-21 of gestation or from days 7-21 of gestation. Fetal body development was assessed. Fetal brain and placental growth were determined by both analysis of organ DNA, RNA and protein and differential radiochemical labelling procedures. Maternal protein restriction inhibited fetal growth. Brain weight was reduced due to a significant decrease in cellular content. Brain cell size was significantly increased and may have accounted for the reduction in cell concentration. Placental growth was similarly impaired. These data demonstrate impaired fetal and placental growth following decreased maternal dietary protein intake. Severity of growth retardation increased with the duration of malnutrition. The results also suggest that malnutrition may affect the rate of development, causing premature cessation of cell division and early cell differentiation.