Localization of pN-type IIA procollagen on adult bovine vitreous collagen fibrils

Type II procollagen is synthesized in long (type IIA) and short (type IIB) forms because of alternative splicing of mRNA; the long form containing an additional cysteine-rich domain in the amino-propeptide. An antiserum (IIA) that recognizes this domain was used for immunolocalization studies on adult bovine vitreous at light and electron microscopic levels and for Western blot analyses. The immunolocalization studies revealed labelling by the IIA antiserum of the vitreous collagen fibrils. This labelling was removed by prior extraction of the fibrils with 6 M guanidine hydrochloride (GuHCl) and the extract was shown to contain pN-type IIA procollagen. Adult vitreous collagen fibrils are coated with pN-type IIA procollagen, a finding with potential implications for vitreous collagen fibril structure and function.

The large chondroitin sulphate proteoglycan versican in mammalian vitreous

Hyaluronan is a major component of the vitreous gel. Hyaluronan-binding macromolecules, including the aggregating proteoglycans, have been shown to perform an important role in maintaining the structural integrity of a number of tissues. However, there have not previously been any biochemical data to establish the presence of these types of macromolecules in vitreous. Bovine vitreous gel was solubilized (apart from a residual collagenous pellet) in 4 M guanidine hydrochloride and after dialysis into phosphate buffered saline analyzed by gel filtration chromatography with in-line measurement of refractive index and multi-angle laser light scattering. The concentration of hyaluronan in whole vitreous was found to be 0.57 mg/ml. The average molecular weight of the hyaluronan was found to be 170,000 (after isolation of the vitreous hyaluronan by isopycnic centrifugation in 0.5 M guanidine hydrochloride and papain digestion). Following Superose 12 gel filtration chromatography of the Streptomyces hyaluronan lyase digested vitreous extract, a pool of material was identified at or near the void volume of the column, and this material was shown to contain sulphated proteoglycans. Analysis of fractions following Superose 12 gel filtration chromatography by Western blotting showed that this pool of material contained the chondroitin sulphate proteoglycans versican and type IX collagen. Link protein was also identified in vitreous extracts by Western blotting. In whole vitreous, the concentration of versican was found to be 21.4+/-2.8 microg/ml and of link protein 0.62+/-0.07 microg/ml. Versican and link protein were thus present in approximately 1:1 molar ratios, but hyaluronan was present in a molar excess of 150 times. Therefore, aggregating proteoglycans are present in vitreous but, assuming that they bind to hyaluronan in-vivo, their overall density along the hyaluronan is much lower than that found in other tissues.

Type VI collagen is present in human and bovine vitreous

BACKGROUND

Heterotypic (mixed) collagen fibrils that contain collagen types II, IX and V/XI have previously been identified in vitreous gel. The purpose of this study was to determine whether vitreous gel also contains type VI collagen microfibrils, as they are widely distributed in other tissues where they may play an important structural role.

METHODS

Bovine and human vitreous gel was analysed by rotary shadowing electron microscopy after bacterial collagenase digestion and gel filtration chromatography. Bovine vitreous was extracted in 4 M guanidine hydrochloride, and following isopycnic centrifugation fractions were analysed by western blotting.

RESULTS

Type VI collagen microfibrils were identified by electron microscopy in human and bovine vitreous. Type VI collagen was identified by western blot analysis.

CONCLUSION

Type VI collagen is present in vitreous and may participate in the structural assembly of the vitreous gel.

Per- and Polyfluoroalkyl Substances (PFAS) in mixtures show additive effects on transcriptomic points of departure in human liver spheroids

Per- and polyfluoroalkyl substances (PFAS) are a wide range of chemicals that are used in a variety of consumer and industrial products leading to direct human exposure. Many PFAS are chemically non-reactive and persistent in the environment, resulting in additional exposure from water, soil, and dietary intake. While some PFAS have documented negative health effects, data on simultaneous exposures to multiple PFAS (PFAS mixtures) are inadequate for making informed decisions for risk assessment. The current study leverages data from previous work in our group using Templated Oligo-Sequencing (TempO-Seq™) for high-throughput transcriptomic analysis of PFAS-exposed primary human liver cell spheroids; herein, we determine the transcriptomic potency of PFAS in mixtures. Gene expression data from single PFAS and mixture exposures of liver cell spheroids were subject to benchmark concentration (BMC) analysis. We used the 25th lowest gene BMC as the point of departure to compare the potencies of single PFAS to PFAS mixtures of varying complexity and composition. Specifically, the empirical potency of eight PFAS mixtures were compared to predicted mixture potencies calculated using the principal of concentration addition (i.e., dose addition) in which mixture component potencies are summed by proportion to predict mixture potency. In this study, for most mixtures, empirical mixture potencies were comparable to potencies calculated through concentration addition. This work supports that the effects of PFAS mixtures on gene expression largely follow the concentration addition predicted response and suggests that effects of these individual PFAS in mixtures are not strongly synergistic or antagonistic.

Boarding versus day-students: A mixed-methods analysis of sleep and its relationship with psychological distress

BACKGROUND

Boarding students face unique challenges when entering school, including: adapting to a novel environment, where they are separated from family, friends and culture, for up to 40 weeks per year. A particular challenge is sleep. A further challenge is coping with the demands of boarding with its potential impact on psychological well-being.

AIMS

To explore how boarders' sleep differs from that of their day-student peers, and how this relates to psychological well-being.

SAMPLE AND METHODS

309 students (59 boarding students and 250 day-students, at one Adelaide school) completed the School Sleep Habits Survey, Depression-Anxiety-Stress-Scale-21 (DASS-21), and Flourishing Scale. Boarding students additionally completed the Utrecht Homesickness Scale. Thirteen boarding students described experiences of sleeping in boarding through focus groups.

RESULTS

Boarding students, compared to day-students reported 40 minutes more sleep per weeknight (p < .001), with earlier sleep onset (p = .026), and later wake-up (p = .008) times. No significant differences were observed between boarding' and day-students' DASS-21 scores. Hierarchical regression revealed longer total weekday sleep time predicted higher psychological well-being in both boarding and day-students. Additionally, in boarding students, low homesickness-loneliness and homesickness-ruminations further predicted psychological well-being. Thematic analysis of boarding students' focus group responses revealed that night-time routine, and restricting technology use at night facilitated sleep.

CONCLUSIONS

This study supports - in both boarding and day-students - the importance of sleep for adolescent well-being. Sleep hygiene can play an important role in boarding student sleep, especially: regular night-time routine and restricting technology use at night. Finally, these findings suggest that poor sleep and homesickness have an adverse effect on boarding student psychological well-being. This study highlights the importance of strategies which promote sleep hygiene and minimize homesickness, in boarding school students.

Why and How Civic Health Should Be Incorporated Into Medical Education

Civic health refers to the ability of a community to organize and collectively address problems that affect the well-being of its members through democratic participation. Civic health should be an integral part of the medical school curriculum because improving a community's civic health shifts the distribution of power toward patients, better enabling them to address social determinants of health that are affecting their well-being. This article details how to effectively integrate civic health curriculum into already-existing medical education frameworks, outlines how these interventions will improve both patient care and the student experience, and addresses barriers that might restrict the implementation. Civic health can be integrated into the didactic curriculum in the form of lunchtime guest lectures, panels with community organizations, and small-group discussions; it can be integrated into experiential curriculum by distributing QR codes to aid in voter registration, organizing voter registration drives, and participating in nonpartisan canvassing. This civic health content can be integrated into existing social justice curricula without massive investment or structural change. Medical students are capable and effective messengers of civic health and can affect change at all levels of training. Notably, because civic health is directly actionable, it can be a source of motivation rather than burnout for medical students. As students develop into medical professionals, the training in civic health improves their understanding of social determinants of health and enables them to play an important role in promoting civic engagement and empowering patients with the democratic tools necessary to enact social change.

A Mixed-Methods Study of Creative Problem Solving and Psychosocial Safety Climate: Preparing Engineers for the Future of Work

The future of work is forcing the world to adjust to a new paradigm of working. New skills will be required to create and adopt new technology and working methods. Additionally, cognitive skills, particularly creative problem-solving, will be highly sought after. The future of work paradigm has threatened many occupations but bolstered others such as engineering. Engineers must keep up to date with the technological and cognitive demands brought on by the future of work. Using an exploratory mixed-methods approach, our study sought to make sense of how engineers understand and use creative problem solving. We found significant associations between engineers’ implicit knowledge of creativity, exemplified creative problem solving, and the perceived value of creativity. We considered that the work environment is a potential facilitator of creative problem-solving. We used an innovative exceptional cases analysis and found that the highest functioning engineers in terms of knowledge, skills, and perceived value of creativity, also reported working in places that facilitate psychosocially safe environments to support creativity. We propose a new theoretical framework for a creative environment by integrating the Four Ps (Person, Process, Product, and Press) and psychosocial safety climate theory that management could apply to facilitate creative problem solving. Through the acquisition of knowledge to engage in creative problem solving as individuals or a team, a perception of value must be present to enforce the benefit of creativity to the engineering role. The future of work paradigm requires that organisations provide an environment, a psychosocially safe climate, for engineers to grow and hone their sought-after skills that artificial technologies cannot currently replace.

Effects of hyaluronan lyase, hyaluronidase, and chondroitin ABC lyase on mammalian vitreous gel

PURPOSE

To determine the effects of enzymes on mammalian vitreous gel and to thus infer the structural roles of hyaluronan and chondroitin sulfate in the gel.

METHODS

The wet weights of bovine vitreous gels were compared before and after incubation with Streptomyces hyaluronan lyase, chondroitin ABC lyase, testicular hyaluronidase, or buffer alone. The extent of hyaluronan depolymerization was determined by chromatography and that of chondroitin sulfate depolymerization by western blot analysis.

RESULTS

After digestion with Streptomyces hyaluronan lyase (30 U/gel), the gel wet weight was the same as that of controls (incubated with buffer alone) despite 94% of the hyaluronan having been depolymerized; when digested with 100 U/gel, the gel wet weight decreased (to 57% of original wet weight versus 86% for controls, P = < 0.001) and hyaluronan was completely depolymerized. Chondroitin ABC lyase digestion (0.2 U/gel) resulted in a slight reduction in gel wet weight (90% versus 96%, P = < 0.001) and depolymerization of 88% of the hyaluronan; the presence of fully digested chondroitin sulfate chains was established. Digestions with 100 and 500 U/gel of testicular hyaluronidase resulted in a decrease (P = < 0.001, both cases) in gel wet weight (53% versus 82%, 100 U/gel; 57%, versus 86%, 500 U/gel) with 75% and 97% hyaluronan depolymerization, respectively.

CONCLUSIONS

Depolymerization of all vitreous hyaluronan and of chondroitin sulfate resulted in gel wet weight reduction but not gel destruction. Digestion with 30 U/gel of Streptomyces hyaluronan lyase revealed a small pool (6%) of relatively enzyme-resistant hyaluronan that specifically contributed toward maintaining gel wet weight.

Adolescent sleep, distress, and technology use: weekday versus weekend

BACKGROUND

In adolescents, technology use at bedtime is linked to disrupted sleep and psychological distress. Adolescents are known to sleep later on weekends compared to weekdays but whether this leads to greater technology use, and, hence, additional psychological distress is not known. At greater risk maybe adolescents with a late compared to early chronotype, that is a preference for late versus early sleep onset and offset times.

METHOD

Self-reported measures of sleep timing, chronotype (early, neither early nor late, late), technology medium (social media/texting, TV/streaming, and gaming), and psychological distress (DASS-21) were collected from 462 students attending one Australian high school.

RESULTS

Technology use at bedtime was greater on weekends and especially in adolescents with a late chronotype. Social media/texting on weekends was predictive of delayed sleep onset times (β = .120), and shorter sleep (β = -.172). Shorter sleep on weekdays but not on weekends was associated with greater psychological distress. Technology medium and chronotype were not predictive of psychological distress.

CONCLUSIONS

This study confirmed that technology use and its impact on sleep differed on weekdays compared to weekends and that a late chronotype was associated with greater technology use. However, neither technology medium nor chronotype was found to affect psychological distress. While greater autonomy may be granted to adolescents over the weekend regarding sleep behaviour, young people, parents, and clinicians should be mindful of the link between technology use and sleep.