bluuebunny/crossref_metadata_2025 huggingface dataset:
Galectin-3: a key player in microglia-mediated neuroinflammation and Alzheimer's disease
Authors: Tan Yinyin , Zheng Yanqun , Xu Daiwen , Sun Zhanfang , Yang Huan , Yin Qingqing
Published: April 2021

Alzheimer’s disease (AD) is the most common cause of dementia and is characterized by the deposition of extracellular aggregates of amyloid-β (Aβ), the formation of intraneuronal tau neurofibrillary tangles and microglial activation-mediated neuroinflammation. One of the key molecules involved in microglial activation is galectin-3 (Gal-3). In recent years, extensive studies have dissected the mechanisms by which Gal-3 modulates microglial activation, impacting Aβ deposition, in both animal models and human studies. In this review article, we focus on the emerging role of Gal-3 in biology and pathobiology, including its origin, its functions in regulating microglial activation and neuroinflammation, and its emergence as a biomarker in AD and other neurodegenerative diseases. These aspects are important to elucidate the involvement of Gal-3 in AD pathogenesis and may provide novel insights into the use of Gal-3 for AD diagnosis and therapy.
The missing link-participants’ perspectives on transfer from psychosocial interventional contexts to everyday community life: a qualitative synthesis of interventional studies
Authors: Bjørkedal Siv Therese Bogevik , Eplov Lene Falgaard , Møller Tom
Published: April 2021

Background

The aim of this study was to illuminate participants’ experiences with transfer in (1) Illness Management and Recovery (IMR); and (2) two programs based on peer support: Turning Points, and Learn to Tackle Anxiety and Depression (LTAD); and whether peer support within these programs influenced the process of transfer beyond the interventional context. Furthermore, we investigated participants’ experiences with a community-based intervention [Individual Placement and Support (IPS)] to explore perspectives on mechanisms that may eliminate challenges in the transfer process.

Methods

The study was based on semi-structured interviews with participants with mental illness, from four different psychosocial interventions with and without peer support and across interventional settings. The material partly consists of secondary analyses of existing data sets of anonymised, transcribed interviews investigating participants' experience from two psychosocial interventions: Illness Management and Recovery (n = 15), and Individual Placement and Support (n = 12). Additionally, we conducted semi-structured interviews with persons who had participated in one of two peer-led programs: Turning Points and Learn How to Tackle Anxiety and Depression (n = 12). The analysis was guided by a hermeneutic-phenomenological approach to illuminate transfer processes and was based on the template method described by Nigel King.

Results

Applying a transfer perspective on rehabilitation interventions identified everyday life situations where capacities learned during the interventions were utilized and conditions were highlighted that promoted or hindered transfer. Experiential knowledge and peer-exchange made transferal pathways between the interventional context and everyday life. Illness intrusiveness and uncertainty, together with environmental obstacles, generated transferal gaps. Individualized support could partly address these gaps.

Conclusion

Findings from this qualitative study illuminate how peer-support in group-based rehabilitation interventions increased social functioning and developed better self-care strategies that can be transferred to daily life. Interventions situated in mental health settings, e.g. outpatient clinics, had limited impact on participation in broader community life. Advancing rehabilitation services in mental health may benefit from tailoring services to address illness fluctuation and combining group sessions with individualized support together with acknowledging and overcoming environmental obstacles.
Feasibility and acceptability of brief individual interpersonal psychotherapy among university students with mental distress in Ethiopia
Authors: Negash Assegid , Khan Matloob Ahmed , Medhin Girmay , Wondimagegn Dawit , Pain Clare , Araya Mesfin
Published: April 2021

Background

The prevalence of mental distress among university students in low- and middle-income countries (LMICs) is increasing; however, the majority do not receive evidence-based psychological intervention.
This calls for the provision of culturally adapted psychological therapy in higher education institutions in LMICs. The aim of this pilot study is to evaluate the feasibility and acceptability of Interpersonal Psychotherapy adapted for Ethiopia (IPT-E) among Wolaita Sodo University students and to assess the preliminary outcomes of IPT-E in reducing symptoms of mental distress and in improving functioning.

Methods

We used a quasi-experimental single-group pre-post-test study design. As indicators of feasibility of IPT-E, we used consent, treatment completion and attrition. We used Client Satisfaction Questionnaire and semi-structured interview to measure the acceptability of the intervention,
self-reporting IPT-E checklist to assess treatment adherence and World Health Organization Disability Assessment and Self-Reporting Questionnaire-20 tools to assess functional impairment and mental distress, respectively. We used percentage, frequency, mean and standard deviation to summarize the demographic variables, feasibility and acceptability of IPT-E. We analyzed changes from pre- to post-tests of mental distress and functioning results using paired t-test and Wilcoxon signed-rank tests. Independent sample t-test and one way-ANOVA used to assess the difference in mean score of in demographic variables at baseline and eight weeks. The qualitative data was analyzed with the support of open code 4.02.

Results

IPT-E was feasible (consent rate = 100%; completion rate = 92.31%; attrition rate = 7.69%; mean score of the sessions = 8 and mode of the session = 8). The total mean score of treatment satisfaction was 27.83 (SD = 4.47). After the delivery of IPT-E, symptoms of mental distress were decreased, functioning was improved and therapist adherence to the treatment model was 100% (i.e. treatment delivered according to the IPT-E guideline).

Conclusion

IPT-E was feasible and acceptable to treat university students with mental distress in low-income country setting. The preliminary results also suggest promising viability of IPT-E in higher education institutions of low-income country setting for students with symptoms of anxiety and depression.
High-fat diet accelerate hepatic fatty acids synthesis in offspring male rats induced by perinatal exposure to nonylphenol
Authors: Zhang Hongyu , Song Chengguang , Yan Rong , Cai Hongbo , Zhou Yi , Ke Xiaoyu
Published: April 2021

Background

Low dose of NP exposure can alter adipose tissue formation, and the intake of high-fat diet (HFD) can also lead to the fatty liver disease. We investigated the combined effect of NP and HFD on the first offspring of rats, and whether this effect can be passed to the next generation and the possible mechanisms involved.

Methods

Pregnant rats had access to be treated with 5 μg/kg/day NP and normal diet. The first generation rats were given normal diet and HFD on postnatal day 21, respectively. Then the second generation rats started to only receive normal diet without NP or HFD. Body weight, organ coefficient of liver tissues, lipid profile, biochemical indexes and the expression of genes involved in lipid metabolism, as well as liver histopathology were investigated in male offspring of rats.

Results

NP and HFD interaction had significant effect on the birth weight, body weight and liver tissue organ coefficient of first generation male rats. And HFD aggravated abnormal lipid metabolism, even abnormal liver function and liver histopathological damage of first generation male rats produced by the NP. And this effect can be passed on to the second generation rats. HFD also accelerated the mRNA level of fatty acid synthesis genes such as Lpl, Fas, Srebp-1 and Ppar-γ of first generation rats induced by perinatal exposure to NP, even passed on to the second generation of male rats. NP and HFD resulted in synergistical decrease of the protein expression level of ERα in liver tissue in F2 male rats.

Conclusion

HFD and NP synergistically accelerated synthesis of fatty acids in liver of male offspring rats through reducing the expression of ERα, which induced abnormal lipid metabolism, abnormal liver function and hepatic steatosis. Moreover, all of these damage passed on to the next generation rats.
Elastic reflection traveltime inversion with pure-wave propagators
Authors: Liang Zhanyuan , Zheng Yi , He Chuanlin , Wu Guochen , Zhang Xiaoyu , Gai Zhipeng
Published: April 2021

Elastic full-waveform inversion (EFWI) updates high-resolution model parameters by minimizing the misfit function between the observed and modeled data. EFWI possesses strong nonlinearity and is likely to converge to a local minimum when the inversion begins with inaccurate initial models. Elastic reflection waveform inversion (ERWI) recovers the low-wavenumber components of P- and S-wave velocities along the “rabbit ear” wavepaths to provide initial velocity models for EFWI. However, every iteration of ERWI requires six times as many forward calculations with elastic-wave equations, which can be computationally expensive. Hence, we have developed a pure-wave reflection waveform inversion (PRWI) approach, which sequentially inverts low-wavenumber components of P- and S-wave velocity models. In our PRWI, we decompose elastic-wave operators into background and perturbed pure-wave parts and derive PRWI gradients using pure-wave operators. The background and perturbed wavefields in PRWI gradients are vector wavefields with a single wave mode. PRWI can remove the high-wavenumber noise caused by S-wave stress decomposition and reduce the computational cost of ERWI by almost 70%. Under the framework of PRWI, we have further developed the pure-wave reflection traveltime inversion (PRTI) approach to alleviate the issue of cycle skipping caused by waveform mismatch. To ensure the recovery of low-wavenumber components, we mute out the contribution of wavefields with small opening angles to PRTI gradients. Numerical examples have demonstrated that our PRTI method can efficiently provide good initial velocity models for EFWI.
Plasma cfDNA Genotyping in Hospitalized Patients With Suspected Metastatic NSCLC
Authors: Cheng Michael L. , Milan Marina S. D. , Tamen Rubii M. , Bertram Arrien A. , Michael Kesi S. , Ricciuti Biagio , Kehl Kenneth L. , Awad Mark M. , Sholl Lynette M. , Paweletz Cloud P. , Jänne Pasi A.
Published: April 2021

PURPOSE

Next-generation sequencing (NGS) is an important component of first-line treatment selection for metastatic non–small-cell lung cancer (NSCLC) and is typically ordered by medical oncologists in the outpatient setting after the pathologic diagnosis has been established. Time to treatment initiation is an important clinical challenge, especially for patients with rapidly progressive disease.

METHODS

Plasma cell-free DNA (cfDNA) NGS was performed on 20 patients with suspected metastatic NSCLC hospitalized at an academic cancer center, before pathologic diagnosis. Clinicopathologic and treatment data were analyzed. Time from pathologic diagnosis to genotyping result was compared with standard care groups who underwent plasma or tumor NGS in routine clinical care.

RESULTS

The median time from pathologic diagnosis to the plasma cfDNA NGS result was 3 days in the study cohort, versus 18 days and 35.5 days in the standard care plasma and tumor NGS groups, respectively. 68.4% of evaluable patients had metastatic NSCLC, and 21.1% had another advanced solid tumor. Forty-five percent of plasma cfDNA results demonstrated actionable or informative genomic variants, and 20% of patients received standard or investigational first-line targeted therapy as a direct result of the plasma cfDNA NGS.

CONCLUSION

Plasma cfDNA NGS before pathologic diagnosis in hospitalized patients with suspected metastatic NSCLC results in substantially shorter time to genotyping result compared with standard outpatient workflows. This provides important initial evidence for the use of plasma-based genotyping earlier in the diagnostic journey, especially for patients with clinically aggressive disease. Additional studies and innovative approaches toward regulatory and reimbursement considerations are needed.
Faster Lumbar Spine Bone Loss in Midlife Predicts Subsequent Fracture Independent of Starting Bone Mineral Density
Authors: Shieh Albert , Karlamangla Arun S , Huang Mei-Hua , Han Weijuan , Greendale Gail A
Published: April 2021

Context

Bone mineral density (BMD) decreases rapidly during menopause transition (MT), and continues to decline in postmenopause.

Objective

This work aims to examine whether faster BMD loss during the combined MT and early postmenopause is associated with incident fracture, independent of starting BMD, before the MT.

Methods

The Study of Women’s Health Across the Nation, a longitudinal cohort study, included 451 women, initially premenopausal or early perimenopausal, and those transitioned to postmenopause. Main outcome measures included time to first fracture after early postmenopause.

Results

In Cox proportional hazards regression, adjusted for age, body mass index, race/ethnicity, study site, use of vitamin D and calcium supplements, and use of bone-detrimental or -beneficial medications, each SD decrement in lumbar spine (LS) BMD before MT was associated with a 78% increment in fracture hazard (P = .007). Each 1% per year faster decline in LS BMD was related to a 56% greater fracture hazard (P = .04). Rate of LS BMD decline predicted future fracture, independent of starting BMD. Women with a starting LS BMD below the sample median, and an LS BMD decline rate faster than the sample median had a 2.7-fold greater fracture hazard (P = .03). At the femoral neck, neither starting BMD nor rate of BMD decline was associated with fracture.

Conclusion

At the LS, starting BMD before the MT and rate of decline during the combined MT and early postmenopause are independent risk factors for fracture. Women with a below-median starting LS BMD and a faster-than-median LS BMD decline have the greatest fracture risk.
An Intact Krüppel-like factor 9 Gene Is Required for Acute Liver Period 1 mRNA Response to Restraint Stress
Authors: Knoedler Joseph R , Sáenz de Miera Cristina , Subramani Arasakumar , Denver Robert J
Published: April 2021

The clock protein period 1 (PER1) is a central component of the core transcription-translation feedback loop governing cell-autonomous circadian rhythms in animals. Transcription of Per1 is directly regulated by the glucocorticoid (GC) receptor (GR), and Per1 mRNA is induced by stressors or injection of GC. Circulating GCs may synchronize peripheral clocks with the central pacemaker located in the suprachiasmatic nucleus of the brain. Krüppel-like factor 9 (KLF9) is a zinc finger transcription factor that, like Per1, is directly regulated by liganded GR, and it associates in chromatin at clock and clock-output genes, including at Per1. We hypothesized that KLF9 modulates stressor-dependent Per1 transcription. We exposed wild-type (WT) and Klf9 null mice (Klf9-/-) of both sexes to 1 hour restraint stress, which caused similar 2- to 2.5-fold increases in plasma corticosterone (B) in each genotype and sex. Although WT mice of both sexes showed a 2-fold increase in liver Per1 mRNA level after restraint stress, this response was absent in Klf9-/- mice. However, injection of B in WT and Klf9-/- mice induced similar increases in Per1 mRNA. Our findings support that an intact Klf9 gene is required for liver Per1 mRNA responses to an acute stressor, but a possible role for GCs in this response requires further investigation.
Why Proust Isn’t an “Essayist,” and Why It Matters
Authors: Landy Joshua
Published: April 2021

Proust’s most famous critic claims that he didn’t have “even a vague or confused idea” of how his novel was going to hang together. Others tell us that every statement in the novel is a “transient hypothesis,” that Proust has “made up his mind about nothing,” or even that Proust thinks he himself is “mad” for believing that art has the power to transfigure reality. This paper will explain why none of that is true. As is clear from his essays, his letters, and even his actions, Proust was not an “essayist,” in the Musil sense: not someone, that is, whose assessments were always tentative and provisional, ready to be relinquished at any moment. At least when it comes to the relationship between selfhood, style, and art, Proust had a set of pretty robust beliefs; and those same letters, along with elements of the novel itself, also show that he wasn’t flying without instruments. So why have some critics thought otherwise? Perhaps, in part, it’s because they have assumed the narrator always speaks for Proust. If so, their foundational assumption isn’t just mistaken; it’s also likely to prevent the novel from doing some of its most important work on us, a work not of deconstruction, and not simply of didacticism, but of self-understanding, formal modeling, and habit cultivation, all in the service of a better life.
The transcriptional landscape of the cultured murine middle ear epithelium in vitro
Authors: Mulay Apoorva , Chowdhury Md Miraj K. , James Cameron T. , Bingle Lynne , Bingle Colin D.
Published: April 2021

Otitis media (OM) is the most common paediatric disease and leads to significant morbidity. Although understanding of underlying disease mechanisms is hampered by complex pathophysiology, it is clear that epithelial abnormalities underpin the disease. The mechanisms underpinning epithelial remodelling in OM remain unclear. We recently described a novel in vitro model of mouse middle ear epithelial cells (mMEECs) that undergoes mucociliary differentiation into the varied epithelial cell populations seen in the middle ear cavity. We now describe genome wide gene expression profiles of mMEECs as they undergo differentiation. We compared the gene expression profiles of original (uncultured) middle ear cells, confluent cultures of undifferentiated cells and cells that had been differentiated for 7 days at an air liquid interface (ALI). >5000 genes were differentially expressed among the three groups of cells. Approximately 4000 genes were differentially expressed between the original cells and day 0 of ALI culture. The original cell population was shown to contain a mix of cell types, including contaminating inflammatory cells that were lost on culture. Approximately 500 genes were upregulated during ALI induced differentiation. These included some secretory genes and some enzymes but most were associated with the process of ciliogenesis. The data suggest that the in vitro model of differentiated murine middle ear epithelium exhibits a transcriptional profile consistent with the mucociliary epithelium seen within the middle ear. Knowledge of the transcriptional landscape of this epithelium will provide a basis for understanding the phenotypic changes seen in murine models of OM.
Autumn migratory orientation and route choice in early and late dunlinsCalidris alpinacaptured at a stopover site in Alaska
Authors: Åkesson Susanne , Grönroos Johanna , Bianco Giuseppe
Published: April 2021

We investigated the migratory orientation of early and late captured dunlins, Calidris alpina, by recording their migratory activity in circular orientation cages during autumn at a staging site in southwest Alaska and performed route simulations to the wintering areas. Two races of dunlins breeding in Alaska have different wintering grounds in North America (Pacific Northwest), and East Asia. Dunlins caught early in autumn (presumably Calidris alpinapacifica) oriented towards their wintering areas (east-southeast; ESE) supporting the idea that they migrate nonstop over the Gulf of Alaska to the Pacific Northwest. We found no difference in orientation between adult and juveniles, nor between fat and lean birds or under clear and overcast skies demonstrating that age, energetic status and cloud cover did not affect the dunlins’ migratory orientation. Later in autumn, we recorded orientation responses towards south-southwest suggesting arrival of the northern subspecies Calidris alpinaarcticola at our site. Route simulations revealed multiple compass mechanisms were compatible with the initial direction of early dunlins wintering in the Pacific Northwest, and for late dunlins migrating to East Asia. Future high-resolution tracking would reveal routes, stopover use including local movements and possible course shifts during migration from Alaska to wintering sites on both sides of the north Pacific Ocean.
Influence de la Papaïne sur le Tibia Embryonnaire de Poulet cultivé in Vitro
Authors: Girard par Henri
Published: April 2021

The action of papain on the tibia of fowl embryos has been studied. The effect of papain-containing media upon the explanted 7-day tibia is very rapid. After 1 hour exposure to fluid medium or 4 hours in contact with a solid one (containing 1·2 mg./ml. papain) the matrix of the cartilage has disappeared completely. Growth on solid medium is much reduced and matrix is not formed. On transfer after 1 or 2 days to a fresh, papain-free medium, based on embryo extract, the tibia resumes its growth at about the normal rate, but does not always regain the size of the control. Chondrocytes do not appear to have been injured by papain since they resume secretion of matrix. An enriched medium, whose formula is given, facilitates the resumption of matrix secretion, but reduces the growth rate of the tibia and has this effect also on controls. In high concentrations (3·7 mg./ml.) papain has a more lasting effect on chondrocytes. On transfer to papain-free medium the growth rate of tibias is less fully restored. Several synthetic milieux were examined, but because of their relative lack of nutritive substances, none proved favourable for the resumption of growth of 7-day tibias. Tibias of 5-day embryos are not so severely affected by papain. After transfer to normal medium their growth rate is equal to that of controls. Papain, finally, has an action on 7-day embryonic cartilage which is, within limits, reversible.
Transforming Growth Factor-β signalling in extraembryonic mesoderm is required for yolk sac vasculogenesis in mice
Authors: Goumans Marie-José , Zwijsen An , Rooijen Marga A. van , Huylebroeck Danny , Roelen Bernard A. J. , Mummery Christine L.
Published: April 2021

We have analysed the function of transforming growth factor β (TGF-β) in yolk sac development in mice by generating somatic chimaeras in which the extraembryonic mesoderm, which gives rise to the endothelial and haematopoietic cells of the yolk sac vasculature, is derived from embryonic stem (ES) cells. The ES cells were stably transfected and express either the full-length type II binding receptor or a kinase-deficient mutant of this receptor. Examination of yolk sacs from chimaeras between E8.5 and 9.5, and analysis of marker expression in embryoid bodies from these mutant ES cell lines in prolonged suspension culture demonstrated that (1) a major function of TGF-β in yolk sac mesoderm is to regulate production and deposition of fibronectin in the extracellular matrix that maintains yolk sac integrity, (2) TGF-β signalling is not required for differentiation of extraembryonic mesoderm into endothelial cells but is necessary for their subsequent organisation into robust vessels, and (3) TGF-β signalling must be tightly regulated for the differentiation of primitive haematopoietic cells to take place normally. Together, these results show that defective TGF-β signalling in the extraembryonic mesoderm alone is sufficient to account for the extraembryonic phenotype reported previously in TGF-β1−/− mice (Dickson, M. C., Martin, J. S., Cousins, F. M., Kulkarni, A. B., Karlsson, S. and Akhurst, R. J. (1995) Development 121, 1845-1854).
Parathyroid hormone-related protein signaling is necessary for sexual dimorphism during embryonic mammary development
Authors: Dunbar Maureen E. , Dann Pamela R. , Robinson Gertraud W. , Hennighausen Lothar , Zhang Jian-Ping , Wysolmerski John J.
Published: April 2021

Male mice lack mammary glands due to the interaction of circulating androgens with local epithelial-mesenchymal signaling in the developing mammary bud. Mammary epithelial cells induce androgen receptor (AR) within the mammary mesenchyme and, in response to androgens, the mesenchyme condenses around the epithelial bud, destroying it. We show that this process involves apoptosis and that, in the absence of parathyroid hormone-related protein (PTHrP) or its receptor, the PTH/PTHrP receptor (PPR1), it fails due to a lack of mesenchymal AR expression. In addition, the expression of tenascin C, another marker of the mammary mesenchyme, is also dependent on PTHrP. PTHrP expression is initiated on E11 and, within the ventral epidermis, is restricted to the forming mammary epithelial bud. In contrast, PPR1 expression is not limited to the mammary bud, but is found generally within the subepidermal mesenchyme. Finally, transgenic overexpression of PTHrP within the basal epidermis induces AR and tenasin C expression within the ventral dermis, suggesting that ectopic expression of PTHrP can induce the ventral mesenchyme to express mammary mesenchyme markers. We propose that PTHrP expression specifically within the developing epithelial bud acts as a dominant signal participating in cell fate decisions leading to a specialized mammary mesenchyme.
Prostatic growth and development are regulated by FGF10
Authors: Thomson A. A. , Cunha G. R.
Published: April 2021

We have examined the role of Fibroblast Growth Factor 10 (FGF10) during the growth and development of the rat ventral prostate (VP) and seminal vesicle (SV). FGF10 transcripts were abundant at the earliest stages of organ formation and during neonatal organ growth, but were low or absent in growth-quiescent adult organs. In both the VP and SV, FGF10 transcripts were expressed only in a subset of mesenchymal cells and in a pattern consistent with a role as a paracrine epithelial regulator. In the neonatal VP, FGF10 mRNA was expressed initially in mesenchymal cells peripheral to the peri-urethral mesenchyme and distal to the elongating prostatic epithelial buds. At later stages, mesenchymal cells surrounding the epithelial buds also expressed FGF10 transcripts. During induction of the SV, FGF10 mRNA was present in mesenchyme surrounding the lower Wolffian ducts and, at later stages, FGF10 transcripts became restricted to mesenchymal cells subadjacent to the serosa. We investigated whether the FGF10 gene might be regulated by androgens by analysing the levels of FGF10 transcripts in SV and VP organs grown in serum-free organ culture. While FGF10 transcript levels increased after treatment with testosterone in the SV (but not VP), these changes were not sensitive to anti-androgen treatment, and thus it is likely that FGF10 mRNA was not directly regulated by testosterone. Also, FGF10 mRNA was observed in the embryonic female reproductive tract in a position analogous to that of the ventral prostate in males suggesting that FGF10 is not regulated by androgens in vivo. Recombinant FGF10 protein specifically stimulated growth of Dunning epithelial and BPH1 prostatic epithelial cell lines, but had no effect on growth of Dunning stromal cells or primary SV mesenchyme. Furthermore, FGF10 protein stimulated the development of ventral prostate and seminal vesicle organ rudiments in serum-free organ culture. When both FGF10 and testosterone were added to organs in vitro, there was no synergistic induction of development. Additionally, development induced by FGF10 was not inhibited by the addition of the anti-androgen Cyproterone Acetate demonstrating that the effects of FGF10 were not mediated by the androgen receptor. Taken together, our experiments suggest that FGF10 functions as a mesenchymal paracrine regulator of epithelial growth in the prostate and seminal vesicle and that the FGF10 gene is not regulated by androgens

Abbreviations: SV, Seminal vesicle; VP, ventral prostate; FGF10, Fibroblast growth factor 10; KGF, Keratinocyte growth factor; FGFR2, Fibroblast growth factor receptor 2; SVM, Seminal vesicle mesenchyme; VMP, Ventral mesenchymal pad.
An Electron Microscope Study of the Cartilaginous Matrix in the Developing Tibia of the Fowl
Authors: Martin Angela V. W.
Published: April 2021

The methods of optical and electron histology have been applied to the study of structural changes in the cartilaginous matrix of the developing fowl tibia. A fine fibrous component without distinctly recognizable periodic structure occurs in the cartilage matrix throughout development and in adult life. Collagen-fibres appear later than the ‘unbanded’ fibrils and develop differently in the different regions of the tibia. The possible significance of these observations is discussed.
Transplantation of Living Nuclei of Late Gastrulae into Enucleated Eggs of Rana pipiens
Authors: King Thomas J. , Briggs Robert
Published: April 2021

In previous papers it has been shown that living nuclei of animal hemisphere cells of frog blastulae and early gastrulae can be transferred into enucleated eggs (Briggs & King, 1952,1953a). Approximately 20 per cent, to 40 per cent, of the recipient eggs cleave normally, and the majority of these develop into complete embryos, demonstrating that the transplanted nuclei are undifferentiated (i.e. still capable of participating in all types of differentiation). This result is more or less expected since the nuclei in question come from undifferentiated parts of the blastula and early gastrula.
Growth and development of pattern in the cranial neural epithelium of rat embryos during neurulation
Authors: Morriss-Kay Gillian M.
Published: April 2021

The pattern of growth and morphogenesis of the cranial neural epithelium of rat embryos during neurulation is described. Transverse sections of the midbrain/hindbrain neural epithelium at different stages (0–14 somites) show a constant area and cell number throughout neurulation, even though there is a high level of mitosis. Mitotic spindles are orientated parallel to the long axis of the embryo, so that increase in cell number occurs in this direction only. Growth is expressed only as an increase in size of the forebrain, which projects rostrad to the tip of the notochord.

In the midbrain/upper hindbrain regions, cellular organization of the neural epithelium changes from columnar to cuboidal to pseudostratified, while its shape changes from flat to biconvex to V shaped. Closure is immediately preceded by neural crest cell emigration from the lateral edges. Throughout neurulation the cranial notochord develops an increasingly convex curvature in the rostrocaudal plane. The attached neural epithelium curves with the notochord (forming the primary cranial flexure) so that as its lateral edges move dorsomedially they form a more distant concentric arc with that of the notochord, and are hence stretched during the final closure period.

The whole rat embryo culture technique was used to investigate the morphogenetic role of proteoglycans during neurulation, neural crest cell emigration and other events in the lateral edge region prior to closure, and the importance of microfilament contraction during concave curvature of the neural epithelium.
Thiopurines correct the effects of autophagy impairment on intestinal healing – a potential role for ARHGAP18/RhoA
Authors: Prins Marileen M. C. , Giugliano Francesca P. , van Roest Manon , van de Graaf Stan F. J. , Koelink Pim J. , Wildenberg Manon E.
Published: April 2021

The ATG16L1 T300A single-nucleotide polymorphism (SNP) is associated with Crohn's disease and causes an autophagy impairment. We have previously shown that this SNP is involved in the migration and hyperactivation of Rac1 in dendritic cells. Mucosal healing, currently the main target for inflammatory bowel disease treatment, depends on restoration of the epithelial barrier and requires appropriate migration of epithelial cells towards and over mucosal lesions. Therefore, we here further investigated the impact of autophagy on epithelial migration.

ATG16L1 knockdown was established in the HT29 human colonic epithelial cell line using lentiviral transduction. Migratory capacity was evaluated using scratch assays and RhoAGTP was measured using G-LISA. Immunofluorescent ARHGAP18 and sequestome 1 (SQSTM1; also known as p62) staining was performed on HT29 cells and primary colonic tissue of Crohn's disease patients.

We observed that ATG16L1 knockdown cells exhibited decreased autophagy and decreased migration capacity. Furthermore, activity of RhoA was decreased. These characteristics were phenocopied using ATG5 knockdown and pharmacological inhibition of autophagy. The migration defect was dependent on accumulation of SQSTM1 and was alleviated upon SQSTM1 knockdown. Strikingly, thiopurines also mitigated the effects of impaired autophagy. RhoA dysregulation appeared mediated through accumulation of the upstream regulator ARHGAP18, which was observed in cell lines, human foetal organoids and primary colonic tissue.

Our results indicate that the ATG16L1 T300A Crohn's disease-associated SNP causes a decrease in migration capacity in epithelial cells, mediated by an increase in SQSTM1 and ARHGAP18 protein and subsequent reduced RhoA activation.
Nature of mutations conferring resistance to 8-azaguanine in mouse cell lines
Authors: Shin Seung-IL
Published: April 2021

Two stable mouse cell mutants A9 and RAG, which are resistant to 8-azaguanine and deficient in hypoxanthine-guanine phosphoribosyl transferase (HGPRT), have been studied in order to establish the nature of molecular changes conferring the mutant phenotypes. A specific precipitating rabbit antiserum was prepared against the normal HGPRT purified from mouse tissues, and used to test for cross-reacting material (CRM) in the mutant lysates. Neither mutants contained detectable cross-reacting material, as demonstrated by precipitation inhibition tests. However, the L cell-derived mutant A9 was shown to have a low but significant level of HGPRT activity which was clearly different from that of the normal enzyme in the wildtype parental cell line. Compared to the wild-type enzyme, the HGPRT in A9 is extremely heat labile, and has an elevated substrate-binding constant in addition to distinct antigenic differences. Both A9 and RAG have been shown previously to revert to the normal phenotype with low frequency, thus ruling out gene deletions as a possible cause of the 8-azaguanine resistance. It is suggested that RAG could involve a recessive regulatory mutation, while A9 may contain a structurally altered HGPRT as a result of a missense mutation within the structural gene for this enzyme.
Molecular hybridization of mouse satellite DNA-complementary RNA in ultrathin sections prepared for electron microscopy
Authors: Jacob J. , Gillies Katherine , Macleod D. , Jones K. W.
Published: April 2021

The feasibility of in situ hybridization in tissue sections prepared for electron microscopy has been examined using mouse satellite DNA-complementary RNA and mouse L cells. The results obtained are encouraging, although certain technical aspects require further clarification. In interphase cells, hybrid-forming sites occur in chromatin patches positioned along the nuclear envelope. It is also confirmed that satellite DNA occurs in nucleolus-associated chromatin. The results suggest that satellite sequences are present in intranucleolar and peri-nucleolar chromatin. A similar distribution is indicated for ribosomal cistrons.
An autoradiographical study of the localization of the uptake of glutamate by the peripheral nerves of the crab, Carcinus maenas (L.)
Authors: Evans P. D.
Published: April 2021

An autoradiographical localization of the uptake sites of [3H]glutamate has been performed on the peripheral nerves of Carcinus maenas (L.) at both the light- and electron-microscope levels. Biochemical control analyses have also been carried out at various stages of the fixation procedure. A statistical analysis of the grain distribution between the glial (and connective tissue) and axonal compartments revealed that it was highly non-random. A comparison has been made of the grain distribution obtained with the ‘circle analysis’ method with that from the ‘hypothetical grain distribution analysis’. The latter analysis revealed that the specific activity of label in the glial compartment was about seven times that of the axonal compartment. The significance of a preferential accumulation of glutamate by the glial compartments in this tissue is discussed in relation to similar findings in other tissues.
Interpretation of the threedimensional structure of living nuclei by specimen tilt
Authors: Skaer R. J. , Whytock Susan
Published: April 2021

A mechanism is described that enables a specimen to be tilted through a known angle and continuously observed under the highest power of the optical microscope. Objects can thus be localized accurately in space. This facility in conjunction with serial optical sectioning by Nomarski optics has been used to construct models of the arrangement of polytene chromosomes in nuclei of Drosophila, Simulium and Chironomus. Telomeres and chromocentre lie on the nuclear envelope. In Simulium they lie close to an equator of the nucleus. Despite these constraints, different nuclei in the same gland do not resemble each other closely.
Adhesion of phytophthora palmivora zoospores: detection and ultrastructural visualization of concanavalin a-receptor sites appearing during encystment
Authors: Sing V. O. , Bartnicki-Garcia S.
Published: April 2021

The binding of concanavalin A (Con A) to the cell surface of zoospores and cysts of Phytoph-thora palmivora was studied by radiometry (l25I-Con A), ultraviolet microscopy (fluorescein-Con A) and electron microscopy (peroxidase-diaminobenzidine technique). Zoospores were found to secrete during the early stages of encystment a Con A-binding material susceptible to trypsin digestion. This glycoprotein is contained in the so-called peripheral vesicles and is probably responsible for the adhesion of the encysting zoospores to solid surfaces.
Colchicine inhibition of stalk elongation in Carchesium sp.: Effect of Ca2+ and Mg2+
Authors: Rahat M. , Friedlaender Hanna , Pimstein Rachel
Published: April 2021

The effect of colchicine on stalk elongation in the colonial peritrich ciliate Carchesium sp. has been investigated by growing this protozoon in colchicine-containing media. The length of the stalk in control cultures was 0·4–0·9 mm. In the presence of 2’5-12’5 mM colchicine, stalk elongation was inhibited, and stalk length was inversely proportional to colchicine concentration. At concentrations above 7·5 mM colchicine, stalks measured less than 01 mm, and sometimes contained imperfect myonemes. The rate of cell fission was retarded in colchicine-containing media, but nevertheless short-stalked colonies with apparently normal zooids were formed. On transfer of such colonies to media without colchicine normal growth was resumed, but only the newly formed branches were of normal length and contractility.

The inhibitory effect of colchicine was annulled by Ca2+ and Mg2+ at 10−3 and 10−4 M, respectively. At lower concentrations of Mg2+ but in the presence of Ca2+, the effect of col-chicine was less conspicuous than at low Ca2+ concentration in presence of Mg2+. Lowering Mga+ concentration at low Ca2+ concentration, increased the inhibitory effect of colchicine.

It is concluded that colchicine-sensitive, probably tubulin-like proteins, participate in the formation of the contractile stalk of Carchesium. Ca2+ and Mg2+ probably compete with col-chicine for a common site in these proteins, or they might reduce the cell’s permeability to this drug.
Calcium-binding proteins in a vorticellid contractile organelle
Authors: Amos W. B. , Routledge L. M. , Yew F. F.
Published: April 2021

The proteins of the contractile spasmoneme of Zoothamnium have been examined for comparison with other motile systems. Though capable of calcium-induced contraction, glycerinated preparations of the spasmoneme contain neither actin nor tubulin at levels that can be detected in polyacrylamide gels. Sixty per cent of the protein in sodium dodecyl sulphate gels migrates in a band at a molecular weight of approximately 20000, consisting largely of 2 similar protein species which are here given the name of spasmins. The amino acid composition of 2 spasmin fractions has been determined by a fluorimetric method. They are rich in Asx, Glx and serine, but have few aromatic amino acids and no cystine or methionine. In calcium-buffered poly-acrylamide gels, it was observed that a reduction in the electrophoretic mobility of the spasmins was induced specifically by calcium (but not magnesium) at the same low concentiations as induce contraction. This indicates that the spasmins are calcium-binding proteins which may be involved directly in the calcium-induced contraction of the spasmoneme.
Lanthanum penetration in crayfish nervous system: Observations on intact and ‘desheathed’ preparations
Authors: Lane Nancy J. , Swales Lesley S. , Abbott N. Joan
Published: April 2021

Central neural connectives and peripheral nerves from the crayfish Procambarus clarkii were incubated in 5 mM lanthanum solutions in physiological saline, for periods from 15 min to 2 h. The tracer only rarely reaches the axon surfaces in the perineurium-ensheathed connectives, penetrating the elaborate perineurial layer slowly. In peripheral nerves, on the other hand, where the perineurium is extremely attenuated and interrupted by open extracellular clefts, inward movement of lanthanum to the axon surfaces occurs readily. When the perineurial layer of the neural connectives is removed by ‘desheathing’, penetration of the tracer to the level of the axolemma occurs rapidly, implicating the perineurium as the major site of restriction of entry of large ions and exogenous molecules. This conclusion is discussed in relation to recent electrophysiological studies on K+ movements.

In both peripheral nerves and desheathed connectives, the transcellular tubular lattice system present in crustacean glial cells appears to serve as a route for the entry of tracer to the axon surfaces, and is more direct than the long and complex extracellular pathway formed by the interdigitations of the extensive glial cell processes.
Precise levels of the Drosophila adaptor protein Dreadlocks maintain the size and stability of germline ring canals
Authors: Stark Kara , Crowe Olivia , Lewellyn Lindsay
Published: April 2021

Intercellular bridges are essential for fertility in many organisms. The developing fruit fly egg has become the premier model system to study intercellular bridges. During oogenesis, the oocyte is connected to supporting nurse cells by relatively large intercellular bridges, or ring canals. Once formed, the ring canals undergo a 20-fold increase in diameter to support the movement of materials from the nurse cells to the oocyte. Here, we demonstrate a novel role for the conserved SH2/SH3 adaptor protein Dreadlocks (Dock) in regulating ring canal size and structural stability in the germline. Dock localizes at germline ring canals throughout oogenesis. Loss of Dock leads to a significant reduction in ring canal diameter, and overexpression of Dock causes dramatic defects in ring canal structure and nurse cell multinucleation. The SH2 domain of Dock is required for ring canal localization downstream of Src64 (also known as Src64B), and the function of one or more of the SH3 domains is necessary for the strong overexpression phenotype. Genetic interaction and localization studies suggest that Dock promotes WASp-mediated Arp2/3 activation in order to determine ring canal size and regulate growth.

This article has an associated First Person interview with the first author of the paper.
Cytological studies on physodes in the vegetative cells of Cystoseira stricta sauvageau (Phaeophyta, Fucales)
Authors: Pellegrini Liliane
Published: April 2021

Physodes have been recognized in meristodermic and promeristematic cells by correlated light- and electron-microscope investigations using different fixation procedures. They are vesicles which contain an osmiophilic material of phenolic nature. Their content changes in appearance according to the fixative used. Osmiophilic deposits are often associated with coiled and disturbed lamellar formations.

It has been possible to distinguish Feveral ultrastructural stages which occur during the secretion of the content of the physodes, namely: a chloroplast accumulation and exudation, and a reticular transport to accumulation vacuoles where materials undergo evolution or hydrolysis. Inside plastids, osmiophilic granules are found in close association with thylakoid stacks. They may contain the polyphenolic precursors of physodes, though this has not yet been proved by electron-microscope procedures. They are expelled from plastids to the chloroplast endoplasmic reticulum. The mechanism of transfer through the chloroplast envelope remains to be elucidated. Lytic activities have been reported inside physodes which might thus act in the same way as the secondary lysosomes of animals and higher plants. Occasionally, the physode content seems to be excreted from the cytoplasm to the cell walls by exocytosis after the probable fusion of plasmalemma and tonoplast.

These cytological changes, observed in the vegetative apex of a brown alga, recall some ultrastructural characteristics of the secretory processes described in various glandular tissues of higher plants and which consist of the synthesis, the transport and the elimination of an exudate of flavonic, terpenic or lipophenolic nature.
Development of the mitochondrial mass and accumulation of mtdna in previtellogenic stages of Xenopus laevis oocytes
Authors: Callen J. C. , Dennebouy N. , Mounolou J. C.
Published: April 2021

The development of the mitochondrial mass of the previtellogenic oocytes of Xenopus laevis has been analysed by a morphometric method and it has been correlated with the growth of the oocyte itself. The study which was performed with oocytes from females of very different ages shows that the relative size of the mitochondrial mass in the smallest oocytes decreases gradually with the age of the females. Cytophotometric analysis of the Feulgen-stained mitochondrial mass enabled the mtDNA content of that structure to be quantified during its development. This development involves about 12 rounds of replication out of the total 16 –17 rounds of replication during complete differentiation of large oocytes. It is possible to estimate the mean replication rate of the mtDNA during the course of the previtellogenic period. The calculated rate of replication is very high in the mitochondrial mass of all the growing oocytes of very young females (about 1 –2 months old), then it decreases rapidly when the oocytes reach 120 μm in diameter.

These results suggest that the mitochondrial masses found in small oocytes of old females do not correspond to sites of active mitochondrial biogenesis but rather they represent a physiologically arrested collection of organelles. Thus the aggregation of mitochondria is the cytological expression of rapid and strictly localized mitochondriogenesis only in very young females.