Designing scaffolds for valvular interstitial cells: cell adhesion and function on naturally derived materials

Valvular interstitial cells (VICs) possess many properties that make them attractive for use in the construction of a tissue-engineered valve; however, we have found that the surfaces to which VICs will adhere and spread are limited. For example, VICs adhere and spread on collagen and laminin-coated surfaces, but display altered morphology and do not proliferate. Interestingly, fibronectin (FN) was one adhesion protein that facilitated VIC adhesion and proliferation. Yet VICs did not spread on surfaces modified with RGD, a ubiquitous cell-adhesive peptide, nor with other FN-specific peptide sequences such as EILDV and PHSRN. Hyaluronic acid (HA) is a highly elastic polysaccharide that is involved in natural valve morphogenesis and possesses binding interactions with FN. Hyaluronic acid was modified to form photopolymerizable hydrogels, and VICs were found to spread and proliferate on HA-based gels, forming a confluent monolayer on the gels within 4 days. Modified HA retained its ability to specifically bind FN, allowing for the formation of gels containing both HA and FN. Valvular interstital cells cultured on HA surfaces displayed significantly increased production of extracellular matrix proteins, indicating that HA-based scaffolds may provide useful biological cues to stimulate heart valve tissue formation.     

Dietary composition of pregnant women is related to size of the baby at birth

The fetal origins theory of adult disease suggests that term infants who are small for their gestational age have an increased susceptibility to chronic disease in adulthood as a consequence of physiologic adaptations to undernutrition during fetal life. Consistent evidence for an influence of women's dietary composition during pregnancy on growth of their babies is lacking, despite robust effects in animal experiments. We undertook a prospective observational study of 557 women aged 18-41 y, living in Adelaide, South Australia. Diet was assessed in early and late pregnancy using an FFQ. In early pregnancy, medians for energy intake, the proportion of energy derived from protein and from carbohydrate were 9.0 MJ, 17 and 48%, respectively. In late pregnancy the corresponding medians were 9.2 MJ, 16 and 49%. In early pregnancy, the percentage of energy derived from protein was positively associated with birth weight (P = 0.02) and placental weight (P = 0.07), independently of energy intake and weight gain during pregnancy, and after adjustment for potential confounders, including maternal age, parity, and smoking. Effects were stronger among women (n = 429) who had reliable data, based on prespecified criteria including the plausibility of dietary data when referenced against estimated energy expenditure. In addition, for this subgroup, the percentage of energy from carbohydrate in early and late pregnancy was negatively associated with ponderal index of the baby, and a specific effect of protein from dairy sources was identified. These data support the proposition that maternal dietary composition has an effect on fetal growth. Maternal diet in Western societies may therefore be important for the long-term health of the child.     

The anatomical basis for modulatory convergence in the antennal lobe of Manduca sexta

The release of neuromodulators by widely projecting neurons often allows sensory systems to alter how they process information based on the physiological state of an animal. Neuromodulators alter network function by changing the biophysical properties of individual neurons and the synaptic efficacy with which individual neurons communicate. However, most, if not all, sensory networks receive multiple neuromodulatory inputs, and the mechanisms by which sensory networks integrate multiple modulatory inputs are not well understood. Here we characterized the relative glomerular distribution of two extrinsic neuromodulators associated with distinct physiological states, serotonin (5‐HT) and dopamine (DA), in the antennal lobe (AL) of the moth Manduca sexta. By using immunocytochemistry and mass dye fills, we characterized the innervation patterns of both 5‐HT‐ and tyrosine hydroxylase‐immunoreactive processes relative to each other, to olfactory receptor neurons (ORNs), to projection neurons (PNs), and to several subsets of local interneurons (LNs). 5‐HT immunoreactivity had nearly complete overlap with PNs and LNs, yet no overlap with ORNs, suggesting that 5‐HT may modulate PNs and LNs directly but not ORNs. TH immunoreactivity overlapped with PNs, LNs, and ORNs, suggesting that dopamine has the potential to modulate all three cell types. Furthermore, the branching density of each neuromodulator differed, with 5‐HT exhibiting denser arborizations and TH‐ir processes being sparser. Our results suggest that 5‐HT and DA extrinsic neurons target partially overlapping glomerular regions, yet DA extends further into the region occupied by ORNs. J. Comp. Neurol. 524:1859–1875, 2016. © 2015 Wiley Periodicals, Inc.     

Rapid genoserotyping tool for classification of Salmonella serovars

We have developed a Salmonella genoserotyping array (SGSA) which rapidly generates an antigenic formula consistent with the White-Kauffmann-Le Minor scheme, currently the gold standard for Salmonella serotyping. A set of 287 strains representative of 133 Salmonella serovars was assembled to validate the array and to test the array probes for accuracy, specificity, and reproducibility. Initially, 76 known serovars were utilized to validate the specificity and repeatability of the array probes and their expected probe patterns. The SGSA generated the correct serovar designations for 100% of the known subspecies I serovars tested in the validation panel and an antigenic formula consistent with that of the White-Kauffmann-Le Minor scheme for 97% of all known serovars tested. Once validated, the SGSA was assessed against a blind panel of 100 Salmonella enterica subsp. I samples serotyped using traditional methods. In summary, the SGSA correctly identified all of the blind samples as representing Salmonella and successfully identified 92% of the antigens found within the unknown samples. Antigen- and serovar-specific probes, in combination with a pepT PCR for confirmation of S. enterica subsp. Enteritidis determinations, generated an antigenic formula and/or a serovar designation consistent with the White-Kauffmann-Le Minor scheme for 87% of unknown samples tested with the SGSA. Future experiments are planned to test the specificity of the array probes with other Salmonella serovars to demonstrate the versatility and utility of this array as a public health tool in the identification of Salmonella.     

Distinct effects of testosterone on plasma and cerebrospinal fluid amyloid-beta levels

The effect of testosterone on the levels of the Alzheimer's disease amyloid-beta peptide (Abeta) was investigated in guinea pigs. Castrated guinea pigs (GPX) were administered testosterone at two different dosages, following which plasma and cerebrospinal fluid (CSF) Abeta_{40} levels were measured. Plasma Abeta_{40} levels were reduced in GPX in the early stages of low-dose testosterone treatment, whereas CSF Abeta_{40} levels were only reduced by the time circulating testosterone had returned to untreated GPX levels. The supraphysiological testosterone dose did not reduce CSF Abeta_{40} levels significantly until circulating testosterone was back to uncastrated levels, whereas plasma Abeta_{40} levels significantly increased over time in these animals. These results indicate that the extent of testosterone-induced changes to Abeta_{40} levels and their response rates depend on both the tissue examined and testosterone dosage.     

Examining Differences in Breath Alcohol Concentration (BrAC) Levels and Hazardous Drinking by Smoking Status Among a Sample of College Student Bar Patrons

While the association between current smoking and alcohol consumption is well known, the relationship between social smoking and alcohol consumption is less understood. The purpose of this study was to examine the association between smoking status and two alcohol consumption measures in a sample of college student bar patrons. The data used in this study was collected in fall 2015. Study participants (N?=?415) were college student bar patrons who agreed to complete an interview that assessed smoking status (i.e., regular smoker, social smoker, non-smoker) and two alcohol consumption measures: (1) breath alcohol concentration (BrAC) levels (using a handheld breathalyzer device) and (2) hazardous drinking scores (using the AUDIT-C scale). We conducted one-way ANOVAs with Bonferroni correction to examine differences in BrAC levels and hazardous drinking scores by smoking status. Among sample participants, 25.3% were regular smokers, 14.7% were social smokers, and 60.0% were non-smokers. Smokers had significantly higher BrAC levels than social smokers and non-smokers. Regular smokers also had significantly higher hazardous drinking scores than social smokers and non-smokers. The BrAC levels and hazardous drinking scores of social smokers and non-smokers were not significantly different. The drinking habits of social smokers reflected those of non-smokers and being a regular smoker was associated with higher drinking levels than the rest of the sample. Because of the association found between alcohol consumption and regular smoking, combining efforts to reduce these behaviors in college students might be advantageous.     

Experimental and computational analysis of cellular interactions with nylon-3-bearing substrates

The ability to design biomaterials that interact with biological environments in a predictable manner necessitates an improved understanding of how surface chemistry influences events such as protein adsorption and cell adhesion. In this work, we examined mechanisms governing the interactions between 3T3 fibroblasts and nylon-3 polymers, which have a protein-like polyamide backbone and are highly amenable to tuning of chemical and physical properties. Protein adsorption and cell adhesion to a library of nylon-3 polymers were characterized and analyzed by partial least squares regression. This analysis revealed that specific chemical features of the nylon-3 polymers correlated with the extent of protein adsorption, which, in turn, correlated with cell adhesion in a serum-containing environment. In contrast, in a serum-free environment, cell adhesion could be predicted solely from chemical properties. Enzymatic treatments of 3T3 cells before plating indicated that proteins bound to the cell surface mediated cell-nylon-3 polymer interactions under serum-free conditions, with additional analysis suggesting that cell-associated fibronectin played a dominant role in adhesion in the absence of serum. The mechanistic insight gained from these studies can be used to inform the design of new polymer structures in addition to providing a basis for continued development of nylon-3 copolymers for tissue engineering applications. ? 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2750-2759, 2012.     

A Research Mentor Training Curriculum for Clinical and Translational Researchers

Purpose

To design and evaluate a research mentor training curriculum for clinical and translational researchers. The resulting 8‐hour curriculum was implemented as part of a national mentor training trial.

Method

The mentor training curriculum was implemented with 144 mentors at 16 academic institutions. Facilitators of the curriculum participated in a train‐the‐trainer workshop to ensure uniform delivery. The data used for this report were collected from participants during the training sessions through reflective writing, and following the last training session via confidential survey with a 94% response rate.

Results

A total of 88% of respondents reported high levels of satisfaction with the training experience, and 90% noted they would recommend the training to a colleague. Participants also reported significant learning gains across six mentoring competencies as well as specific impacts of the training on their mentoring practice.

Conclusions

The data suggest the described research mentor training curriculum is an effective means of engaging research mentors to reflect upon and improve their research mentoring practices. The training resulted in high satisfaction, self‐reported skill gains as well as behavioral changes of clinical and translational research mentors. Given success across 16 diverse sites, this training may serve as a national model. Clin Trans Sci 2013; Volume 6: 26–33