Cell culture and karyotypic description of Pseudophrynecoriacea (Keferstein, 1868) (Amphibia, Anura) from the New South Wales Central Coast

The karyotype of the IUCN least concern red-backed toadlet Pseudophryne (P.) coriacea (Keferstein, 1868) from the New South Wales Central Coast is described following tissue culture of toe clipping macerates and conventional DAPI staining. The diploid number is 2n = 24. The karyotype is represented by six large and five small chromosomal pairs and one very small chromosomal pair. The very small chromosome 12 is 12% the size of chromosome 1. One of the large chromosomes is subtelocentric, two of the large chromosomes are submetacentric and the remaining chromosomes are metacentric. The putative nucleolus organiser region (NOR) is observed on chromosome 4. The diploid number and location of the putative NOR correlates to that of the previously published IUCN critically endangered P.corroboree (Moore 1953) and unpublished descriptions of the P.coriacea karyotype. This is the first described cell culture of a species from the genus Pseudophryne Fitzinger, 1843, first published analysis of the P.coriacea karyotype and the first published analysis of centromeric allocation of this genus. Globally there exists a large inventory of tissue samples in cryobanks that are not associated with known recovery mechanisms such as basic cell culture techniques. Detailed cytogenetic analyses of these cryobanked samples are therefore not possible. This work therefore enables: (i) a comparison of the P.coriacea karyotype with that of the critically endangered P.corroboree and (ii) a benchmark for repeat and future cytogenetic and genomic analyses of cryostored samples of this genus.

Induction of endoplasmic reticulum stress is associated with the anti-tumor activity of monepantel across cancer types

BACKGROUND

Monepantel is an anti-helminthic drug that also has anti-cancer properties. Despite several studies over the years, the molecular target of monepantel in mammalian cells is still unknown, and its mechanism-of-action is not fully understood, though effects on cell cycle, mTOR signalling and autophagy have been implicated.

METHODS

Viability assays were performed on >20 solid cancer cell cells, and apoptosis assays were performed on a subset of these, including 3D cultures. Genetic deletion of BAX/BAK and ATG were used to establish roles of apoptosis and autophagy in killing activity. RNA-sequencing was performed on four cell lines after monepantel treatment, and differentially regulated genes were confirmed by Western blotting.

RESULTS

We showed that monepantel has anti-proliferative activity on a broad range of cancer cell lines. In some, this was associated with induction of apoptosis which was confirmed using a BAX/BAK-deficient cell line. However, proliferation is still inhibited in these cells following monepantel treatment, indicating cell-cycle disruption as the major anti-cancer effect. Previous studies have also indicated autophagic cell death occurs following monepantel treatment. We showed autophagy induction in multiple cell lines; however, deletion of a key autophagy regulator ATG7 had minimal impact on monepantel's anti-proliferative activity, suggesting autophagy is associated with, but not required for its anti-tumour effects. Transcriptomic analysis of four cell lines treated with monepantel revealed downregulation of many genes involved in the cell cycle, and upregulation of genes linked to ATF4-mediated ER stress responses, especially those involved in amino-acid metabolism and protein synthesis.

CONCLUSIONS

As these outcomes are all associated with mTOR signalling, cell cycle and autophagy, we now provide a likely triggering mechanism for the anti-cancer activity of monepantel.

A preliminary assessment of oral monepantel's tolerability and pharmacokinetics in individuals with treatment-refractory solid tumors

PURPOSE

Monepantel is an approved veterinary anthelmintic with a strong safety profile. Preclinical evidence suggests novel mTOR pathway-associated anticancer activity. An open-label Phase I trial assessed tolerability, pharmacokinetics, pharmacodynamics and PET-CT imaging following oral Zolvix^® monepantel administration to adults with treatment refractory, progressing and unresectable solid tumors.

METHODS

Subjects were scheduled to daily home-based monepantel administration for 28 days in a 3 + 3 dose escalation study (5.0, 25.0 and 62.5 mg/kg bw).

RESULTS

Of 41 reported drug-related AEs, 68% were Grade 1 and 24% were Grade 2; 35 AEs related to gastrointestinal effects including very poor palatability. DLT and MTD could not be determined due to early termination. Myelosuppression was not observed at the lowest level tested. Three of four Cohort 1 subjects had reduced mTOR pathway marker p-RPS6KB1 levels in PBMCs and achieved RECISTv1.1 SD by CT; one had progressive bony metastases by FDG-PET. One subject recorded PD on day 28, correlating with no detectable plasma monepantel from day 7. Monepantel sulfone dominated monepantel in pharmacokinetics. Both Cohort 2 subjects withdrew early due to AEs and the trial was terminated.

CONCLUSIONS

Short-term 5 mg/kg bw monepantel administration provides a combined steady-state trough plasma monepantel and monepantel sulfone concentration of 0.5 μM. Gastrointestinal AEs including very poor palatability are concerning and suggested to be resolved by future drug product reformulation. RECISTv1.1, p-RPS6KB1 and plasma tumor marker outcomes provide preliminary evidence of anticancer activity.

Karyomaps of cultured and cryobanked Litoria infrafrenata frog and tadpole cells

These data and analyses support the research article “Culture, cryobanking and passaging of karyotypically validated native Australian amphibian cells” Mollard (2018) [1]. The data and analyses presented here include: (1) three additional karyomaps of cells from the cryobanked and passaged frog and tadpole species Litoria infrafrenata; and (2) combined short-to-long arm ratios of the four karyomaps measured from each respective animal here and in Ref [1].

Fresh Noncultured Endothelial Progenitor Cells Improve Neonatal Lung Hyperoxia-Induced Alveolar Injury

Treatment of preterm human infants with high oxygen can result in disrupted lung alveolar and vascular development. Local or systemic administration of endothelial progenitor cells (EPCs) is reported to remedy such disruption in animal models. In this study, the effects of both fresh (enriched for KDR) and cultured bone marrow (BM)-derived cell populations with EPC characteristics were examined following hyperoxia in neonatal mouse lungs. Intraperitoneal injection of fresh EPCs into five-day-old mice treated with 90% oxygen resulted in full recovery of hyperoxia-induced alveolar disruption by 56 days of age. Partial recovery in septal number following hyperoxia was observed following injection of short-term cultured EPCs, yet aberrant tissue growths appeared following injection of long-term cultured cells. Fresh and long-term cultured cells had no impact on blood vessel development. Short-term cultured cells increased blood vessel number in normoxic and hyperoxic mice by 28 days but had no impact on day 56. Injection of fresh EPCs into normoxic mice significantly reduced alveolarization compared with phosphate buffered saline-injected normoxic controls. These results indicate that fresh BM EPCs have a higher and safer corrective profile in a hyperoxia-induced lung injury model compared with cultured BM EPCs but may be detrimental to the normoxic lung. The appearance of aberrant tissue growths and other side effects following injection of cultured EPCs warrants further investigation. Stem Cells Translational Medicine 2017;6:2094-2105.

Interruption of a Monotonous Activity with Complex Tasks: Effects of Individual Differences

The fluctuations of vigilance and performance for operators working in monotonous conditions were studied in laboratory. Three experimental designs were achieved on 20 subjects:

— one reference condition with a vigilance task of 3 hours 30 during day time, — one experimental condition with interruptions of monotony during the vigilance task by a sustained task, during the same day time period, — the same experimental condition during night time.

The purpose was to analyse the effect of breakdown in monotony on arousal and human performance and to look for individual differences in human performance. Physiological data were collected in order to study the variation of arousal. Response times and omissions were used as performance index. Individual differences can be observed for performance and vigilance. Two kinds of behavior are defined: stable subjects and subjects characterized by fluctuations both for arousal and performance during the task. During day time period, breakdown of monotony has a positive effect on performance especially for subjects with fluctuations of arousal. Night time condition creates a sleep deprivation and the consequence is that the efficiency of the reactivation due to breakdown by sustained task is not demonstrated. Results are discussed in regard of the theory of Fisk and Schneider on automated and controlled mental processing during monotonous activities.

Human Force Exertion: The Significance of the Measure?

A basic research was conducted on a sample of twelve right-handed young males for pull actions of the upper limb on a gauge handle. The general purpose is to constitute an atlas of forces for french males, useful for ergonomics studies. Different conditions were tested before to select a standard protocol. Main difficulties concern the elimination of lower limbs contribution, the stability of the posture, the motivation of the subject and the choice of the parameters for the measure. Intra-individual variability in function of the protocols is in a range of 20-30%. With the usual standard protocol, this variability still remains if we try to evaluate maximal pull force during a week period. The interpretation of these data is not clear, and a more accurate definition of the measure is necessary before recommendations for normative data. Time duration of 5 seconds, real-time display of the force and maximal peak value seem to be an acceptable solution by comparison with a functional effort on a torque wrench that reflects a realistic action. It is proposed to use this procedure for the next experiments.

A new way to apply ultrasound in cross-flow ultrafiltration: application to colloidal suspensions

A new coupling of ultrasound device with membrane process has been developed in order to enhance cross-flow ultrafiltration of colloidal suspensions usually involved in several industrial applications included bio and agro industries, water and sludge treatment. In order to reduce mass transfer resistances induced by fouling and concentration polarization, which both are main limitations in membrane separation process continuous ultrasound is applied with the help of a vibrating blade (20 kHz) located in the feed channel all over the membrane surface (8mm between membrane surface and the blade). Hydrodynamic aspects were also taking into account by the control of the rectangular geometry of the feed channel. Three colloidal suspensions with different kinds of colloidal interaction (attractive, repulsive) were chosen to evaluate the effect of their physico-chemical properties on the filtration. For a 90 W power (20.5 W cm(-2)) and a continuous flow rate, permeation fluxes are increased for each studied colloidal suspension, without damaging the membrane. The results show that the flux increase depends on the initial structural properties of filtered dispersion in terms of colloidal interaction and spatial organizations. For instance, a Montmorillonite Wyoming-Na clay suspension was filtered at 1.5 × 10(5)Pa transmembrane pressure. Its permeation flux is increased by a factor 7.1, from 13.6 L m(-2)h(-1) without ultrasound to 97 L m(-2)h(-1) with ultrasound.

Transient vascular and long-term alveolar deficits following a hyperoxic injury to neonatal mouse lung

Background

The lungs of very preterm human babies display deficits in alveolarization and vascularization as a result of the clinical use of high oxygen treatment (leading to hyperoxia) required to decrease the risk of mortality. Detailed analyses of the persistence of the respiratory deficits following this treatment and means to restore a normal state have not been investigated in full detail. In this study, high oxygen administration to neonatal mouse lungs was established as a proxy to hyperoxia in human preterm infant lungs, to better characterize the associated deficits and thus provide a means to assist in the development of treatments in the future.

Methods

Ninety percent oxygen was administered to newborn mice for four consecutive days. The effects of this treatment upon alveolarization and vascularization were investigated by morphometric, histochemical, immunohistochemical and protein analyses at day five (D5), D28 and D56 postpartum.

Results

Relative to control untreated lungs, septation of hyperoxic lungs was significantly reduced and airspaces were significantly enlarged at all stages examined. Furthermore, compared to controls, the number of secondary septa per tissue area was significantly reduced at D5, significantly increased at D28 and then the same as controls at D56. Analysis of vascularization parameters indicated a reduction in mature blood vessel number and the amount of Pecam1 at D5. Both of these parameters returned to control levels by D28.

Conclusions

This study suggests that administration of high oxygen to underdeveloped lungs has a transient reductive effect on secondary septal number and pulmonary vascularization and a significant long-term reduction in alveolarization persisting into adulthood. This model can be used for future research of premature lung disease therapies in humans, addressing these short term septal and vascular and long term alveolar deficits, specifically relating to injury by hyperoxia.

cAMP response element binding protein is required for differentiation of respiratory epithelium during murine development

The cAMP response element binding protein 1 (Creb1) transcription factor regulates cellular gene expression in response to elevated levels of intracellular cAMP. Creb1^−/− fetal mice are phenotypically smaller than wildtype littermates, predominantly die in utero and do not survive after birth due to respiratory failure. We have further investigated the respiratory defect of Creb1^−/− fetal mice during development. Lungs of Creb1^−/− fetal mice were pale in colour and smaller than wildtype controls in proportion to their reduced body size. Creb1^−/− lungs also did not mature morphologically beyond E16.5 with little or no expansion of airway luminal spaces, a phenotype also observed with the Creb1^−/− lung on a Crem^−/− genetic background. Creb1 was highly expressed throughout the lung at all stages examined, however activation of Creb1 was detected primarily in distal lung epithelium. Cell differentiation of E17.5 Creb1^−/− lung distal epithelium was analysed by electron microscopy and showed markedly reduced numbers of type-I and type-II alveolar epithelial cells. Furthermore, immunomarkers for specific lineages of proximal epithelium including ciliated, non-ciliated (Clara), and neuroendocrine cells showed delayed onset of expression in the Creb1^−/− lung. Finally, gene expression analyses of the E17.5 Creb1^−/− lung using whole genome microarray and qPCR collectively identified respiratory marker gene profiles and provide potential novel Creb1-regulated genes. Together, these results demonstrate a crucial role for Creb1 activity for the development and differentiation of the conducting and distal lung epithelium.

Interleukin-13 regulates secretion of the tumor growth factor-{beta} superfamily cytokine activin A in allergic airway inflammation

Activin A is a member of the TGF-beta superfamily and plays a role in allergic inflammation and asthma pathogenesis. Recent evidence suggests that activin A regulates proinflammatory cytokine production and is regulated by inflammatory mediators. In a murine model of acute allergic airway inflammation, we observed previously that increased activin A concentrations in bronchoalveolar lavage (BAL) fluid coincide with Th2 cytokine production in lung-draining lymph nodes and pronounced mucus metaplasia in bronchial epithelium. We therefore hypothesized that IL-13, the key cytokine for mucus production, regulates activin A secretion into BAL fluid in experimental asthma. IL-13 increased BAL fluid activin A concentrations in naive mice and dose dependently induced activin A secretion from cultured human airway epithelium. A key role for IL-13 in the secretion of activin A into the BAL fluid during allergic airway inflammation was confirmed in IL-13-deficient mice. Eosinophils were not involved in this response because there was no difference in BAL fluid activin A concentrations between wild-type and eosinophil-deficient mice. Our data highlight an important role for IL-13 in the regulation of activin A intraepithelially and in BAL fluid in naive mice and during allergic airway inflammation. Given the immunomodulatory and fibrogenic effects of activin A, our findings suggest an important role for IL-13 regulation of activin A in asthma pathogenesis.

Neural Stem Cells Express Non-Neural Markers During Embryoid Body Coculture

The capacity of neural stem cells (NSC) to transdifferentiate into a wide range of non-neuronal lineages is the subject of debate. One approach to test NSC plasticity is to ectopically place NSCs in permissive or instructive microenvironments in which the signals driving differentiation of multiple cell types are being elicited. Here we produce embryoid body neurosphere aggregates by combining neurosphere derivatives from fetal mice constitutively expressing green fluorescent protein with embryonic stem (ES) cells isolated from Zin40 mice constitutively expressing nuclear beta-galacosidase. Under these conditions, we assess neurosphere-derivative-immunoreactivity to anti-neurofilament heavy chain, anti-pan-cytokeratin, anti-smooth muscle alpha-actinin and anti-alpha-fetoprotein-specific antibodies. Furthermore, we determine lineage-specific transgene expression and undertake fluorescence in situ hybridization to assess ES cell-neural stem cell-fusion indices. Our data demonstrate that following coculture in hanging drops with ES cells, neurosphere derivatives display immunoreactivity to non-neural markers, in particular smooth muscle, which is not dependent upon cell-cell fusion. These results suggest that given an appropriate environment, NSC may lose their in vivo restrictions and display non-neuronal phenotypes.

Stem cells: an overview

Stem cells are specialized cells that possess a capacity to undergo self-renewal while at the same time having the ability to give rise to at least one or more differentiated or mature cell type. They therefore represent a fundamental cornerstone during the life of all vertebrates, playing central roles in the production of new and replacement cells for tissues during development and homeostasis, including repair following disease or injury. This unit is a review of stem cells, their roles in development, and their potentials as therapeutic agents.

Mouse embryonic stem cell derivation, and mouse and human embryonic stem cell culture and differentiation as embryoid bodies

Embryonic stem (ES) cells are pluripotent cells derived from developing mouse blastocysts in vitro that maintain long-term self renewal and the capacity to give rise to all cell types in the adult body (including some extraembryonic cell types) when subjected to the appropriate conditions. It is envisaged that the development of methods enabling controlled differentiation of mouse ES cell counterparts from human blastocysts would enable the provision of an unlimited supply of tissue for cell and tissue transplantation therapies for the repair and replacement of diseased, injured, and senescent tissue. Furthermore, derivation of mouse ES cells has allowed for the generation of thousands of gene-targeted mouse mutants. Culture of mouse ES cells as embryoid bodies (EBs) has provided a convenient system for studying early mouse developmental processes, including several aspects of extraembryonic lineage and axis formation associated with the pre- and peri-gastrulating mouse embryo. Relatively little is known regarding the corresponding development of the early human embryo due to limitations associated with the acquisition of relevant tissue material for study. The transfer of methods such as EB formation to human systems should, by association, facilitate a more advanced understanding of similar processes associated with early human development. This unit describes protocols for isolating mouse embryonic stem cells and methods for propagating, freezing, and producing EBs from both mouse and human embryonic stem cells.

Deriving respiratory cell types from stem cells

The reported pluripotential capabilities of many human stem cell types has made them an attractive area of research, given the belief they may hold considerable therapeutic potential for treating a wide range of human diseases and injuries. Although the bulk of stem cell based research has focused on developing procedures for the treatment of pancreatic, neural, cardiovascular and haematopoietic diseases, the potential for deriving respiratory cell types from stem cells for treatment of respiratory specific diseases has also been explored. It is suggested that stem cell derivatives may be used for lung replacement/regeneration therapeutics and high though-put pharmacological screening strategies for a variety of respiratory injuries and diseases including: cystic fibrosis, chronic obstructive pulmonary disease, respiratory distress syndrome, pulmonary fibrosis and pulmonary edema. This review will explore recent progress in characterizing adult respiratory and bone marrow derived stem cells with respiratory potential as well as the endogenous mechanisms directing the homing of these cells to the diseased and injured lung. In addition, the potential for embryonic stem cell based therapies in this domain as well as the histological, anatomical and molecular aspects of respiratory development will be summarized.

Selective glucocorticoid receptor ligands

Glucocorticoids are four-ring steroid compounds that regulate a wide range of physiological systems ranging from embryonic respiratory development, immune function and responses to acute or chronic stress. Glucocorticoids are taken up by many target cells where they bind and activate cytoplasmic glucocorticoid receptors (GRs), which then dimerize, translocate to the nucleus and function as ligand-dependent transcriptional regulators. Synthetic glucocorticoids such as dexamethasone and prednisolone have for decades been the cornerstone for the clinical treatment of inflammatory diseases, such as rheumatoid arthritis and asthma, yet prolonged use have undesirable side-effects such as persistent immune suppression, metabolic imbalance, obesity, diabetes, and osteoporosis. Detailed understanding of the cell signaling mechanisms of GR action has led to the development of novel selective glucocorticoid receptor ligands that appear to offer more efficient treatments for a number of diseases while eliciting fewer side-effects. Additionally, in cell-based and animal model systems a number of compounds such as the methane sulphonamides and a novel compound A-348441 have shown promise as GR antagonists. Other classes of ligands such as the benzopyranoquinolines and the arylpyrazoles have further been shown to selectively influence the transcriptional regulatory properties of GRs on different target gene in various cellular contexts. These selective GR modulators are believed to initiate transcriptional co-regulator recruitment that in turn promotes specific gene responses relevant to the more efficient and specific treatment of inflammatory conditions and metabolic diseases such as type-2 diabetes.

Identification of glucocorticoid-regulated genes that control cell proliferation during murine respiratory development

Glucocorticoids play a vital role in fetal respiratory development and act via the intracellular glucocorticoid receptor (GR) to regulate transcription of key target genes. GR-null mice die at birth due to respiratory dysfunction associated with hypercellularity and atelectasis. To identify events associated with this lung phenotype we examined perinatal cellular proliferation rates and apoptotic indices. We demonstrate that compared to wild-type controls, day 18.5 postcoitum (p.c.) GR-null mouse lungs display significantly increased cell proliferation rates (1.8-fold P < 0.05) and no change in apoptosis. To examine underlying molecular mechanisms, we compared whole genome expression profiles by microarray analysis at 18.5 days p.c. Pathways relating to cell proliferation, division and cell cycle were significantly down-regulated while pathways relating to carbohydrate metabolism, kinase activities and immune responses were significantly up-regulated. Differential levels of gene expression were verified by quantitative-RT-PCR and/or Northern analysis. Key regulators of proliferation differentially expressed in the lung of 18.5 p.c. GR-null lungs included p21 CIP1 (decreased 2.9-fold, P < 0.05), a negative regulator of the cell cycle, and Mdk (increased 6.0-fold, P < 0.05), a lung growth factor. The more under-expressed genes in 18.5 p.c. GR-null lungs included Chi3l3 (11-fold, P < 0.05), a macrophage inflammatory response gene and Ela1 (9.4-fold, P < 0.05), an extracellular matrix remodeling enzyme. Our results demonstrate that GR affects the transcriptional status of a number of regulatory processes during late fetal lung development. Amongst these processes is cell proliferation whereby GR induces expression of cell cycle repressors while suppressing induction of a well characterized cell cycle stimulator.

BMPs regulate differentiation of a putative visceral endoderm layer within human embryonic stem-cell-derived embryoid bodies

Human embryonic stem cells (HESCs), pluripotent cells derived from the inner cell mass (ICM) of human blastocysts, represent a novel tool for the study of early human developmental events. When cultured in suspension with serum, HESCs form spherical structures resembling embryoid bodies (EBs). We show that differentiation of HESCs within EBs occurs radially, with central cells then undergoing apoptosis in association with EB cavitation. Cells within the outer layer of cavitating EBs display stage-specific immunoreactivity to pan-keratin, cytokeratin-8, GATA6, alpha-fetoprotein, and transthyretin specific antibodies, and hybridization to disabled-2, GATA4, and GATA6 specific riboprobes. Transmission electron microscopy of these cells reveals clathrin-coated micropinocytotic vesicles, microvilli, and many vacuoles, a phenotype consistent with mouse visceral endoderm (VE) rather than mouse definitive or parietal endoderm. When cultured in media supplemented with the BMP inhibitor noggin, or in the absence of serum, HESC derivatives do not develop the mouse VE-like phenotype. The addition of BMP-4 to noggin-treated HESCs cultured in serum or in serum-free conditions reconstituted development of the VE-like phenotype. These data demonstrate that human EBs undergo developmental events similar to those of mouse EBs and that in vitro BMP signalling induces derivatives of the human ICM to express a phenotype similar to mouse VE.

A murine respiratory-inducing niche displays variable efficiency across human and mouse embryonic stem cell species

Human embryonic stemlike cells (hESCs) are pluripotent cells derived from blastocysts. Differentiating hESCs into respiratory lineages may benefit respiratory therapeutic programs. We previously demonstrated that 24% of all mouse embryonic stem cell (mESC) derivatives cocultured with embryonic day 11.5 (E11.5) mouse lung rudiments display immunoreactivity to the pneumonocyte II specific marker surfactant-associated protein C (Sftpc). Here we further investigate the effects of this inductive niche in terms of its competence to induce hESC derivative SFTPC immunoreactivity and the expression of other markers of terminal lung secretory units. When hESCs were cocultured as single cells, clumps of approximately 10 cells or embryoid bodies (EBs), hESC derivatives formed pan-keratin-positive epithelial tubules at high frequency (>30% of all hESC derivatives). However, human-specific SFTPC immunoreactivity associated with tubule formation only at low frequency (<0.1% of all hESC derivatives). Human-specific SFTPD and secretoglobin family 1A member 1 (SCGB1A1, also known as CC10) transcripts were detected by PCR after prolonged culture. Expression of other terminal lung secretory unit markers (TITF1, SFTPA, and SFTPB) was not detected at any time point analyzed. On the other hand, hESC derivatives cultured as plated EBs in media previously demonstrated to induce Sftpc expression in isolated mouse fetal tracheal epithelium expressed all terminal lung secretory unit markers examined. mESCs and hESCs thus display fundamental differences in their response to the E11.5 mouse lung inductive niche, and these data provide an important step in the delineation of signaling mechanisms capable of efficiently inducing hESC differentiation into terminal secretory units of the lung.

Embryonic stem cells form glandular structures and express surfactant protein C following culture with dissociated fetal respiratory tissue

Mouse embryonic stem cells (MESCs) are pluripotent, theoretically immortal cells derived from the inner cell mass of developing blastocysts. The respiratory epithelium develops from the primitive foregut endoderm as a result of inductive morphogenetic interactions with the surrounding visceral mesoderm. After dissociation of the explanted fetal lung into single cells, these morphogenetic signaling pathways instruct reconstitution of the developing lung according to a process known as organotypic regeneration. Data presented here demonstrate that such fetal lung morphogenetic cues induce MESC derivatives to incorporate into the reforming pseudoglandular-like tubular ducts, display pan-keratin and surfactant protein C (Sftpc) immunoreactivity, and express Sftpc transcripts while displaying a normal diploid karyotype in coculture. The Sftpc inductive capacity of dissociated fetal lung tissue shows stage specificity with 24% of all MESC derivatives displaying Sftpc immunoreactivity after coculture with embryonic day 11.5 (E11.5) lung buds compared with 6% and 0.02% following coculture with E12.5 and E13.5 lung buds, respectively. MESC derivative Sftpc immunoreactivity follows a spatial and temporal specific maturation profile with an initially ubiquitous cellular Sftpc immunostaining pattern becoming apically polarized with time. Directing differentiation of MESCs into respiratory lineages has important implications for cell replacement therapeutics aimed at treating respiratory-specific diseases such as cystic fibrosis and idiopathic pulmonary fibrosis.

Mouse embryonic stem cell colonisation of carbonated apatite surfaces

Apatites play a crucial role in the body and have been used extensively in biomedical implants. The influence on stem cell behaviour is not known and so this study will explore whether sintered carbonated apatites are favourable for propagation of stem cells. Different weight substitutions of carbonated apatite, specifically 2.5 wt% (2.5 wt%CAP) and 5 wt% (5 wt%CAP), were sintered and characterised prior to the investigation of their potential as a matrix for the support of mouse embryonic stem (ES) cells. Characterisation of the apatites included elemental analysis, X-ray diffraction, surface roughness, specific surface area, density, and solubility. The ability of carbonated apatite to support mouse ES cell colonisation and maintenance in the presence of leukaemia inhibitory factor was determined by an enumeration of live versus dead cells within a population, and immunoreactivity to Oct4, a transcription factor and stem cell marker, following growth on each matrix. It was found that while both compositions allowed for the colonisation of mouse ES cells, the cells were not maintained in an undifferentiated state, as evidenced by a reduction in the number of cells staining positive for Oct4 expression. This study shows that an increase in carbonate content within sintered apatites leads to a higher cell number, a desired aspect for stem cells to populate scaffolds intended for tissue engineering. This study presents carbonated apatites as a suitable matrix for the initial colonisation and differentiation of ES cells for tissue engineering applications.

Colonization and maintenance of murine embryonic stem cells on poly(alpha-hydroxy esters)

The aim of this study was to determine the ability of various poly(alpha-hydroxy esters) to support the in vitro propagation of murine embryonic stem (ES) cells in an undifferentiated state. To this end, ES cell colonization, growth and Oct-4 immunoreactivity following a 48 h culture period upon poly((D,L)-lactide), poly((L)-lactide), poly(glycolide) and poly((D,L)-lactide-co-glycolide) (PLGA) were assessed. By the analysis of live and dead cell number indices and Oct-4 immunoreactivity, ES cell colonization rate during a 48 h culture period was found to be significantly greater on PLGA compared to all the other unmodified poly(alpha-hydroxy esters) tested. Surface treatment of all polymers with 0.1m potassium hydroxide revealed a significant increase in ES cell live numbers when compared to all unmodified polymers, thus revealing a correlation between polymer content, hydrophilicity and colonization rate. These data suggest that surface treated poly(alpha-hydroxy esters) may be employed for ES cell scale up procedures and in tissue engineering applications requiring the colonization of scaffolds by ES cells in an undifferentiated state. According to such applications, once the designated scaffold has been colonized, ES cell directed differentiation into the desired and fully differentiated, functional adult tissue may then be effected.

Sintered hydroxyfluorapatites--IV: The effect of fluoride substitutions upon colonisation of hydroxyapatites by mouse embryonic stem cells

Biodegradable scaffolds serve a central role for tissue engineering scaffolds and guiding tissue regeneration. Some of these scaffolds, including apatites, display a significant effect upon cell adhesion and cell proliferation. The incorporation of scaffold technology with the developing embryonic stem (ES) cell field and the capacity of ES cells for self-renewal and differentiation are believed to hold enormous potential for applications in biomedical research and regenerative medicine. The purpose of this work was to determine the effect of hydroxyapatite (HAP) and fluoride substitutions of HAP upon ES cell growth and colonisation. Sintered hydroxyfluorapatite discs were found to support cellular proliferation and colonisation, and the ES cells displayed a tendency for differentiation on the apatite surface as determined by reductions in colony Oct4 immunoreactivity. Fluoride-containing HAPs were found to provide equivalent support to gelatin in terms of cell numbers, yet superior support for cellular colonisation when compared to HAP. This study indicates that fluoride substitutions of HAP may represent a viable strategy for the development of certain engineered tissue replacements and tissue regeneration systems using ES cells.

Human embryonic stem cells form embryoid bodies containing visceral endoderm-like derivatives

OBJECTIVE

The objective of this study was to determine the potential of human embryonic stem (hES) cells to provide an in vitro model of human extraembryonic endoderm development.

METHODS

The hES cell line HES-2 was propagated in Dulbecco's modification of Eagle's medium (DMEM) in the presence of 20% fetal calf serum (FCS) on a mouse embryonic fibroblast feeder layer. Clumps of approximately 50-100 cells were transferred to fresh DMEM and FCS and grown as embryoid bodies (EBs) in suspension culture. EBs were subjected to immunohistochemistry for endodermal, ectodermal and mesodermal specific markers and immunoreactivity analysed by confocal microscopy and on cryosections.

RESULTS

HES-2 cells reproducibly formed spherical EBs after 2-3 days in suspension culture as clumps. EBs continued to expand and by 7 days had commenced cavitation in a highly reproducible and organised fashion. Culture periods longer than 10 days led to cystic structures displaying inconsistent morphological organisation. Immunolocalisation of anti-alpha-fetoprotein-, anti-neurofilament- and anti-CD31-specific antibodies at 7 days of culture provided evidence of regional differentiation of endodermal, ectodermal and mesodermal derivatives in cavitating EBs. Further, of 10 cavitating EBs analysed at 7 days of culture, all displayed immunolocalisation of anti-pan-keratin-, anti-CK8- and anti-alpha-fetoprotein-specific antibodies to a peripheral cellular layer, suggestive of yolk sac visceral endoderm (VE) formation.

CONCLUSION

Cavitation, the presence of regionalised cell lineage-specific immunoreactivity and the development of a VE-like peripheral cell layer demonstrate that the HES-2 hES cell line can be induced to undergo EB formation and provide scope to study early human primitive endoderm and yolk sac VE development.

Derivation, propagation and differentiation of human embryonic stem cells

Embryonic stem (ES) cells are in vitro cultivated pluripotent cells derived from the inner cell mass (ICM) of the embryonic blastocyst. Attesting to their pluripotency, ES cells can be differentiated into representative derivatives of all three embryonic germ layers (endoderm, ectoderm and mesoderm) both in vitro and in vivo. Although mouse ES cells have been studied for many years, human ES cells have only more recently been derived and successfully propagated. Many biochemical differences and culture requirements between mouse and human ES cells have been described, yet despite these differences the study of murine ES cells has provided important insights into methodologies aimed at generating a greater and more in depth understanding of human ES cell biology. One common feature of both mouse and human ES cells is their capacity to undergo controlled differentiation into spheroid structures termed embryoid bodies (EBs). EBs recapitulate several aspects of early development, displaying regional-specific differentiation programs into derivatives of all three embryonic germ layers. For this reason, EB formation has been utilised as an initial step in a wide range of studies aimed at differentiating both mouse and human ES cells into a specific and desired cell type. Recent reports utilising specific growth factor combinations and cell-cell induction systems have provided alternative strategies for the directed differentiation of cells into a desired lineage. According to each one of these strategies, however, a relatively high cell lineage heterogeneity remains, necessitating subsequent purification steps including mechanical dissection, selective media or fluorescent or magnetic activated cell sorting (FACS and MACS, respectively). In the future, the ability to specifically direct differentiation of human ES cells at 100% efficiency into a desired lineage will allow us to fully explore the potential of these cells in the analysis of early human development, drug discovery, drug testing and repair of damaged or diseased tissues via transplantation.

Retinoic acid signaling regulates murine bronchial tubule formation

Treatment of pseudoglandular stage fetal lungs in vitro with the pan-retinoic acid receptor (pan-RAR) antagonist, BMS493, reduces retinoic acid receptor beta (Rarb) gene expression within the proximal bronchial tubules and increases explant bud formation. Treatment with retinoic acid (RA) increases Rarb expression and reduces explant bud formation through a signaling mechanism involving RARbeta. Together these data suggest that RA through RARbeta provides morphogenetic stabilizing activity to the proximal tubules during lung branching morphogenesis. Here we further investigate RA-mediated morphogenetic stabilization of the proximal respiratory tubules during fetal lung development. We demonstrate that Rarb isoform transcripts are the only known Rar transcripts to specifically localize to the proximal tubules and that RAREhsp68lacZ reporter transgene activity reveals endogenous RA signaling activity within these same proximal tubules. Furthermore, the expression patterns of the RA-producing enzyme retinaldehyde dehydrogenase 1 (Raldh1), as well as of transforming growth factor-3beta (Tgfb3), Foxa2, and the cystic fibrosis transmembrane conductance regulator (Cftr) within the proximal tubules are all altered by the application of either RA or BMS493 in vitro. We therefore discuss an interbud/proximal tubule signaling niche involving feedback between Rarb expression and Raldh1-mediated synthesis of RA. We suggest that this feedback favors interbud morphogenetic stability by increasing expression of morphoregulatory molecules such as TGFbeta3 and Foxa2, thus promoting bronchial tubule formation rather than continual budding and branching. The relationship between this RAR signaling center and the previously described distal bud signaling center is also addressed.

Selected genetic factors associated with male infertility

Studies into the mechanisms underlying spermatogenesis, the process by which spermatogonia undergo meiosis to become spermatozoa, have identified a number of genetic determinants of male infertility. Indeed, a more comprehensive knowledge of the genetic regulation of spermatogenesis has alleviated the dependence on the use of idiopathic infertility as a classification for sterile men for whom a cause for their infertility is unknown, as genetic factors become more accountable for this phenotype. This review focuses on selected areas implicated in male infertility including: (i) autosomal and sex chromosomal abnormalities; (ii) genetic disorders associated with impaired gonadotrophin secretion or action; (iii) microdeletions within regions of the Y-chromosome containing candidate gene families for spermatogenesis; (iv) the genetic nexus between cystic fibrosis and congenital bilateral absence of the vas deferens; and (v) insights into human infertility as gleaned from animal studies into mechanisms involving the Bcl-2 family of apoptosis regulators and the interaction between the c-kit encoded tyrosine kinase receptor and its ligand, stem cell factor. As significant advances continue to further knowledge of the genetic basis of male infertility, such as those leading to an understanding of the aforementioned areas, greater progress can be made to rectify or at least ameliorate social stigmas associated with sterility.

Technical advances and pitfalls on the way to human cloning

There exists a widespread consensus that the cloning of human beings to term would be detrimental to both the mother and child and of little value to society. However, the ambition of a few organisations and the recent advances in cellular and molecular technologies that led to the cloning of Dolly the sheep, for example, have meant that such a procedure will be possible if not illegal in the near future. The science associated with the cloning technologies practiced in other mammalian species reported to date provide important advances in our understanding of how cells function during early developmental processes and commit themselves to specific developmental pathways. However, many technological insufficiencies remain. Both technological advances and several of the associated insufficiencies are outlined in this review.

Do morphological anomalies reflect chromosomal aneuploidies?: case report

In cases of severe teratozoospermia, the current morphological criteria used to assess chromosomal status is insufficient for the selection of spermatozoa for intracytoplasmic sperm injection (ICSI). Case histories are reported of four patients presenting 100% teratozoospermia, and the integrity of their individual chromosomal statuses is determined using a three-colour fluorescence in-situ hybridization (FISH) technique. Patient 1 presented shortened flagella syndrome, patient 2 globozoospermia, patient 3 spermatozoa with irregular acrosomes, and patient 4 macrocephalic spermatozoa with associated multiple flagella. Three-colour FISH analysis using chromosome X, Y and 1-specific probes showed that approximately 95% of the spermatozoa analysed from patients 1, 2 and 3 presented X,1 and Y,1 signals, X,Y ratios and aneuploidy/diploidy rates comparable with those observed in normal controls. In contrast, patient 4 showed a highly elevated Y to X sex ratio and a highly elevated aneuploidy/diploidy rate. Three-colour FISH analysis thus demonstrates an increased incidence of chromosomal abnormalities in association with macrocephalic spermatozoa. Moreover, the analysis shows that in patients affected with either globozoospermia, shortened flagella syndrome or a condition of abnormal acrosomal spermatozoa, no association exists between chromosomal status and phenotype. Since these patients display normal haploid, sex chromosome and aneuploidy status, ICSI can be conceivably offered as a treatment for their infertility.

Stage-dependent responses of the developing lung to retinoic acid signaling

Morphological analysis of vitamin A-deficient rat fetuses and of retinoic acid receptor (RAR and RXR) mutant mice have demonstrated that retinoic acid (RA) is essential for lung development. To gainfurther insight into RA signaling pathways during primary lung budformation and lung branching, we have investigated the effects of RA and of a pan-RAR antagonist in cultures of whole embryos and lung explants. Treatment of E8.0 embryos with the pan-RAR antagonist inhibits the formation of the primitive respiratory system. On the other hand, treatment of E11.75 and E12.5 lung explants with RA inhibits branching morphogenesis, whereas treatment with the pan-RAR antagonist at the same developmental stages stimulates formation of distal buds. The inhibitory effect of RA on branching is strongly decreased in RARbeta null lungs, while enhancement of budding by the pan-RAR antagonist is not affected by an RARgamma null mutation. Additionally, cellular retinol binding protein one (CRBPI) null lungs are more sensitive than wild type lungs to the pan-RAR antagonist-induced stimulation of branching. These data indicate that retinoid signaling is indispensable for the formation of primary lung buds and the oesophagotracheal septum from the primitive foregut. They also suggest that at the pseudoglandular stage, RA signaling through RARbeta, but not RARgamma, inhibits distal bud formation thereby promoting the formation of conducting airways. Moreover, the level of CRBPI in the pseudoglandular lung appears to participate in the control of branching morphogenesis.

Histological and genetic analysis and risk assessment for chromosomal aberration after ICSI for patients presenting with CBAVD

Intracytoplasmic sperm injection (ICSI) has opened a new field in the treatment of male infertility, leading to a debate concerning its genetic safety. In this study we present an analysis of 11 patients presenting congenital bilateral absence of the vas deferens (CBAVD). In all 11 cases, genetic counselling, histological analysis of testicular biopsies, cystic fibrosis transmembrane conductance regulator (CFTR) mutation screenings of both partners and spermatozoa three-colour fluorescent in-situ hybridization (FISH) analysis were performed. A total of 31 CFTR mutations were screened and mutations were found in eight out of 11 cases, with DeltaF508 being the most common mutation found. Histological analyses showed that seven out of 11 patients had normal tubule/membrane/interstitium (TMI) and Johnsen scores, while the remaining four patients had mild impairment of testicular parenchyma. The average aneuploidy rate was 6.8 +/- 3.9% compared with two control subjects with 4.4 and 5.4% aneuploidy rates respectively, using FISH analysis. After ICSI, the fertilization and pregnancy rates were 66.2 and 22.7% respectively. Thus, in our case of CBAVD, the risk of chromosomal aberration following ICSI, in the absence of a CFTR mutation in the male patient and/or in his partner, was not higher than in normal fertile men. Furthermore, the pregnancy success rate following ICSI of these CBAVD patients was comparable to the general ICSI population, even when histological analysis showed limited spermatogenesis.

Tissue-specific expression of retinoic acid receptor isoform transcripts in the mouse embryo

The three murine retinoic acid receptor (RAR) genes each contain two distinct promoters which give rise to protein isoforms differing in their N-terminal regions. This study used in situ hybridization to describe the expression patterns of RARalpha1, RARalpha2, RARbeta1/3, RARbeta2/4, RARgamma1 and RARgamma2 isoform transcripts during mouse embryogenesis. RARalpha1 transcripts are widely distributed, with the exception of the central nervous system. Highest expression is found in developing muscle, pituitary gland and various epithelia. On the other hand, RARalpha2 is essentially expressed along the spinal cord up to the hindbrain 7th rhombomere and in the 4th rhombomere, pons and developing basal ganglia (corpus striatum and pallidum). RARbeta2/4 transcripts account for most of the previously described RARbeta expression features being expressed specifically, or more prominently than RARbeta1/3, in foregut endoderm and its derivatives, olfactory and periocular mesenchyme, urogenital region, proximal limb bud mesenchyme and later within interdigital regions. RARbeta1/3 is more prominently expressed in the developing heart outflow tract mesenchyme, intervertebral disks, midgut loop mesenchyme and umbilical vessel walls. RARbeta1/3 and RARbeta2/4 are coexpressed in the developing corpus striatum. They exhibit, however, distinct dorsoventral distributions along the spinal cord and caudal hindbrain. RARgamma2 is the RARgamma isoform expressed at high levels in the caudal neural groove at embryonic day 8.5. At later stages, both RARgamma isoforms are essentially coexpressed, although the progressive restriction of RARgamma1 transcripts to craniofacial or limb precartilaginous condensations appears to precede that of RARgamma2.

A correlation between epithelial proliferation rates, basement membrane component localization patterns, and morphogenetic potential in the embryonic mouse lung

Lung epithelial branching morphogenesis results from a repetitive series of cleft and bud formation, a process dependent upon a complex interaction with the surrounding mesenchyme. The present study describes these cleft- and bud-forming regions as autonomous morphogenetic compartments within the embryonic day 11.5 (E11.5) mouse lung and directly correlates their identity with differences in epithelial proliferation rates and the localization pattern of specific basement membrane components. Lung buds were cultured in vitro, in two-dimensional planes, and labeled with a series of 5-bromo-2'-deoxyuridine (BrdU) pulses. Collectively, epithelial cells within actively budding regions of the bronchiolar tree demonstrated an at least 2.5-fold greater proliferation rate than those situated in the adjacent cleft-forming regions. Epithelial proliferation rates showed an inverse relationship with the degree of immunoreactivity of nidogen, laminin-1, fibronectin, and collagen IV within the underlying basement membrane. Epithelial cells dissected free from mesenchyme demonstrated cell-cell contact-dependent proliferation, thus revealing a hierarchy between mesenchymal signaling and direct epithelial cell-cell communication during branch formation. Dissection of the E11.5 bronchiolar tree into specific distalbud and interbud regions and their in vitro culture demonstrated differences in their autonomous morphogenetic potential. Tissue dissected from the distal tips of the lung continued to branch, whereas tissue dissected from immediately adjacent cleft regions seldom branched. Isolated distalbud tissue also continued to correlate regional differences in epithelial proliferation rates and immunolocalization patterns of nidogen, laminin-1, fibronectin, and collagen IV with branch formation. These results support the basement membrane remodeling hypothesis, thus connecting nidogen, collagen type IV, fibronectin, and laminin-1 localization with the molecular processes directing epithelial proliferation and supporting bud outgrowth and cleft formation/stabilization during lung morphogenesis.

Homeobox genes from clusters A and B demonstrate characteristics of temporal colinearity and differential restrictions in spatial expression domains in the branching mouse lung

Lung branching morphogenesis is accomplished by reciprocal morphogenetic interactions between the epithelium and its mesenchyme. In order to better understand the molecular mechanisms regulating these interactions in time and space, the expression patterns of Hox genes isolated exclusively from the branching region of the developing lung have been investigated. Reverse transcriptase PCR identified Hoxa-1, Hoxa-3, Hoxa-5, Hoxb-3, Hoxb-4, Hoxb-6, Hoxb-7, and Hoxb-8 transcripts from within this tissue at 11.5 day post coitum (E11.5). Northern blot, in situ hybridization and PCR analyses demonstrated qualitative and quantitative differences in expression patterns for each gene assessed in this region thus providing evidence for Hox gene temporal colinearity. Furthermore, although not within the context of strict anteroposterior definition, Hox genes located within a more 5' region in both clusters were found to have greater spatial expression constrictions when compared to their more 3' counterparts. These Hox genes were also differentially expressed both between and within specific germ cell lineage derivatives. Such patterns of expression suggest that Hox genes play a role in the specification and maturation of lung cell lineage derivatives throughout the pseudoglandular, canalicular and terminal sac phases of lung development.

Micromotion, fit, and fill of custom made femoral stems designed with an automated process

This study presents an automated process for the design of custom made femoral stems. Two software programs have been developed to obtain the inner bone contours from computed tomography scan images and to design the optimal stem that can be inserted into the femur. This process requires only 2 hours of computer use, therefore reducing the price of the stem. It is also possible to control the amount of bone sacrifice necessary to facilitate the insertion of the stem. Micromotion for 6 specimens was measured using a special machine simulating the load supported by the hip joint during single-limb stance. Three prostheses were tested successively: anatomic cementless stem, custom made stem, and modified custom made stem in which the distal part was thinned out. To be stabilized, the anatomic prosthesis required a greater number of cycles than custom made stems associated with a more important total vertical migration. The micromotion of custom made prostheses was significantly less than that of the other prostheses. The fill of custom made stems also was measured, having a range from 93% to 100% (mean, 97.5%-98.8%) of the medullary canal. The metaphyseal fill was significantly linked with the vertical and rotational components of instability. These results showed that it was possible, using a computerized automated and controlled process, to obtain low price femoral stems well fitted to the medullary canal that provide an excellent primary stability.

Appropriate use of bright light promotes a durable adaptation to night-shifts and accelerates readjustment during recovery after a period of night-shifts

The present study examines the stability of bright light circadian readjustment during two consecutive dim light night-work periods and circadian synchronization during the recovery after a night-shift period. A sample of 10 subjects was divided into 2 groups (control group : 6 subjects; experimental group: 4 subjects). All subjects worked during 5 days, between 23:00 and 07:00 h and then went to sleep. Subjects received 2500-3000 lux between 02:00 and 05:00 h during 5 days for the control group and 3 days for the experimental group. During recovery after the night-shift periods, three cycles of bright light were administered at two different times: 12:00-15:00 h for two of six subjects from the control group and 10:00-13:00 h for all subjects (4) of the experimental group. By the fifth cycle of night-work the maximum of urinary aMT6s excretion that occurs at 05:00 h in the baseline condition was shifted to 12:00 h for the control and experimental groups (delay in hours: 7 +/- 1.6 (control); 7 +/- 1(experimental)). This result suggests that three cycles of bright light are sufficient to induce a significant phase delay and that this delay remained stable when night-work proceeded under dim light. The phase delay of the circadian aMT6s excretion by exposure to bright light was accompanied by an improvement of the quality of day sleep and level of cognitive and psychomotor performances for control and experimental groups. No significant difference was observed in the two groups for daytime sleep and nocturnal performance. The two bright light periods used during the three days of recovery induced a complete synchronization in five of six subjects. One subject showed a partial sychronization probably because he remained at the laboratory under dim light during the day and had few family and social contacts.

Human vigilance in railway and long-haul flight operation

Human operators in transport operations are often confronted with monotony, boredom, and irregular work schedules. This situation has become increasingly more acute because of the growing automation of systems. This paper presents methodology and preliminary results for two field studies on the vigilance of train drivers and long-range aircrews. The aim of these studies was to identify factors that can modify vigilance and to elaborate several specific solutions for reactivation. The method is based on the collection of physiological data in the field and on task observation of the operators. The recorded physiological data (EEG, EOG, EKG) permit an evaluation of vigilance and mental workload. The rest-activity cycles are estimated by actometry. The use of EEG and EOG are discussed in relation to monotony and sleep deprivation. For pilots, results show a high occurrence of decreased vigilance, particularly during phases of low workload (i.e., when cruising). Furthermore, it was shown that these periods of lowered vigilance can occur at the same time for two crew members. A great number of incidents of decreased vigilance were also observed for the train drivers. These incidents occurred even though the operators sometimes had high levels of activity. A direct relation was also noted between sleep duration and the onset of rest. These studies provide several means for maintaining vigilance during activities and improving the system of work schedule rotation.

An assessment of the deflecting effect on human movement due to the Coriolis inertial forces in a space vehicle

Under conditions of prolonged space flight, it may be feasible to restore gravity artificially using centrifugal inertial forces in a spinning vehicle. As a result, the motion of the passengers relative to the vehicle is affected by Coriolis forces. The aim of this study is to propose a theoretical method to evaluate the extent of these effects compared to other inertial or motor forces affecting movement. We investigated typical right upper limb movement in a numerical model with a two-solid-links mechanism, including a spherical joint for the shoulder and a hinge joint for the elbow. The inertial and dimensional characteristics of this model derive from measurements and computations obtained on laboratory subjects. The same is true for the movements assigned to the model. These were inferred from actual recordings of arm movement when the subject presses a button placed in front of him with his index finger. From these relative velocities, the resulting forces and moments applied to the elbow and the shoulder were computed for a 1 rad s-1 rotational speed of transport motion, using classical kinetic relations. The result is that the Coriolis moments are of the same order of magnitude as the corresponding inertial moments and one-tenth of the value of a typical elbow flexion moment. Thus, they should cause a significant disturbance in movement.

Immunological fine structure of the variable and constant regions of a polymorphic malarial surface antigen from Plasmodium falciparum

The 51-kDa merozoite surface antigen MSA2 of Plasmodium falciparum shows considerable strain-dependent polymorphism. Although marked sequence variation occurs in the central region of the molecule, the N and C-terminal sequences are highly conserved. A number of monoclonal antibodies directed against MSA2 have been described which inhibit parasite growth in vitro, but these are all directed against variable regions. In an attempt to raise strain independent antibodies we have prepared peptide-diphtheria toxoid (DT) constructs from 36 N-terminal octapeptides spanning the constant region and extending into the variable region of the FCQ/27 PNG variant staggered by one amino acid at either end. Similarly, we prepared 26 C-terminal octapeptides spanning the C-terminal constant region as well as 10 octapeptides from the variable region of the Indochina I variant MSA2. Most of the peptides elicited antipeptide titres in excess of 1/10(4) when administered to mice as peptide-DT adducts emulsified with Freund's complete adjuvant. Only 3 of the 43 N- and C-terminal constant region peptides elicited antibodies which reacted appropriately on immunofluorescence (IFA) or immunoblotting analysis with the intact MSA2 of both strains studied (FCQ/27 and Indochina I), whereas 3 other peptides from the variable region elicited antibodies reactive with the parent MSA2 only. Peptide constructs eliciting antibodies recognising the intact protein corresponded to elements in the cognate sequence of high antigenicity as predicted by the Jameson and Wolf algorithm.

Variable linking region immunogenicity using malarial peptide carrier protein conjugates of defined composition

Thirty-five overlapping peptides from both conserved and variable parts of the N-terminal region of a malarial merozoite surface antigen (MSA2) were synthesised using solid phase chemistry. All peptides were synthesised with an added N-terminal cysteine and purified by reverse-phase HPLC to facilitate coupling to a carrier protein diphtheria toxoid (DT) using the hetero-bifunctional reagent maleimidocaproloxysuccinimide (MCS). Mice were immunised with these peptide-DT conjugates using Freund's complete adjuvant (FCA). The immune response of these mice was tested against peptide hapten, carrier protein (DT) and the linking region itself, using enzyme-linked immunoassay (ELISA). Although there was great variation in the immune response to each part of the immunogen construct, no significant correlation could be seen between each set of responses.

Peptide vaccines derived from a malarial surface antigen: effects of dose and adjuvants on immunogenicity

Peptides P2122 (CKNNNSTNSGI) and P513 (CSQRSTNSAST) containing an epitope of a malarial surface antigen (MSA2) recognised by inhibitory monoclonal antibodies were conjugated to diphtheria toxoid (DT) protein and formulated with various gel-based and water in oil emulsion adjuvants in vaccine trials in mice and rabbits. The P2122-DT construct was effective in raising antibodies reactive with both the immunising peptide and the native antigen. Effective adjuvanticity as measured by the titre of the anti-peptide or anti-protein response in mice varied in the order: Algammulin, Montanide ISA 50 greater than or equal to Freund's adjuvant, Montanide ISA 708, 721, 70 much greater than alum, Squalene Arlacel greater than SAF-1. A similar order of adjuvant efficacy: Freund's greater than alum greater than Squalene Arlacel greater than SAF-1, was observed in rabbits.

[Use of x-ray computed tomographic data for the concept of a custom-made hip prosthesis. Exploratory approach]

A custom-made hip prosthesis has to allow to improve the arthroplasty's longevity. In a Computer Aid program Conception (CAD) of such an implant, it becomes necessary to control the accuracy of the 3-D data given by CT Scans. The method employed is based on the comparison between 3-D data given by CT Scans and by photogrammetry. The study was made with a human pelvis including femoral head, without soft tissues. The CT Scans data have been given by automatic extraction of osseous outlines on two hundreds sections (1.5 mm thickness). The photogrammetry data have required five stereocouples for the whole pelvis and four stereocouples for the hip joint (femoral head and cotyle). There nine stereocouples have provided 37,213 points of reference. The comparison between the two sorts of informations shows that the error made in CT Scans acquisition was varying between 0.65 and 1.60 mm. This error is smaller when the outlines are simple, like the femoral diaphyse. The error decreases if we reduce the field size of CT Scan acquisition. These results confirm literature data. But this study has allowed to demonstrate validity of 3-D CT reconstruction. Scanography looks like the best present way of data acquisition. The dimensional précision is sufficient to define the endo-osseous outline, but it must be preserved at the moment of the extraction of this outline. Therefore this extractive can't be manual and must be made directly with processing data given by scanography.