Shaping the zebrafish myotome by intertissue friction and active stress.

Organ formation is an inherently biophysical process, requiring large-scale tissue deformations. Yet, understanding how complex organ shape emerges during development remains a major challenge. During zebrafish embryogenesis, large muscle segments, called myotomes, acquire a characteristic chevron morphology, which is believed to aid swimming. Myotome shape can be altered by perturbing muscle cell differentiation or the interaction between myotomes and surrounding tissues during morphogenesis. To disentangle the mechanisms contributing to shape formation of the myotome, we combine single-cell resolution live imaging with quantitative image analysis and theoretical modeling. We find that, soon after segmentation from the presomitic mesoderm, the future myotome spreads across the underlying tissues. The mechanical coupling between the future myotome and the surrounding tissues appears to spatially vary, effectively resulting in spatially heterogeneous friction. Using a vertex model combined with experimental validation, we show that the interplay of tissue spreading and friction is sufficient to drive the initial phase of chevron shape formation. However, local anisotropic stresses, generated during muscle cell differentiation, are necessary to reach the acute angle of the chevron in wild-type embryos. Finally, tissue plasticity is required for formation and maintenance of the chevron shape, which is mediated by orientated cellular rearrangements. Our work sheds light on how a spatiotemporal sequence of local cellular events can have a nonlocal and irreversible mechanical impact at the tissue scale, leading to robust organ shaping.

Ten-year incidences of self-reported non-vertebral fractures in Japanese patients with rheumatoid arthritis: discrepancy between disease activity control and the incidence of non-vertebral fracture.

UNLABELLED: Despite improvements in rheumatoid arthritis disease activity of in the past 10 years, the incidence of self-reported non-vertebral fractures did not decrease in our cohort of 9,987 patients. This study may indicate that osteoporosis treatment and non-vertebral fracture prevention remain important regardless of the rheumatoid arthritis disease activity. INTRODUCTION: Although rheumatoid arthritis (RA) is a risk factor for osteoporosis and fractures, few studies have described the association between disease activity and the fracture incidence in patients with RA. This study aimed to investigate changes in the non-vertebral fracture incidence between 2001 and 2010 in our Institute of Rheumatology Rheumatoid Arthritis (IORRA) cohort. METHODS: The IORRA is a prospective observational cohort study of Japanese RA patients. A total of 9,987 patients with RA were enrolled in this cohort from 2000 to 2010. The clinical parameter and non-vertebral fracture occurrence data were collected biannually through self-reported questionnaires. Incidences of self-reported non-vertebral fractures were also analyzed via standardization according to gender, age, and disease activity during each 2-year period. RESULTS: From 2001 to 2010, the percentage of patients with 28-joint disease activity score remission increased from 7.8 to 39.7%, prednisolone intake decreased from 51.4 to 41.3%, and bisphosphonate intake increased from 5.0 to 23.4%. The non-vertebral fracture incidence rates were 24.6/1,000 person-years in 2001 and 35.5/1,000 person-years in 2010, with no apparent change even after standardization. The overall non-vertebral fracture incidence was significantly higher in the autumn/winter than in the spring/summer (p = 0.02). CONCLUSION: Despite improvements in disease activity and functional disability, the non-vertebral fracture incidence exhibited no apparent change between 2001 and 2010 in our patients with RA. Osteoporosis treatment and non-vertebral fracture prevention remain important regardless of the disease control in patients with RA.

Prevalence and progression of radiographic ossification of the posterior longitudinal ligament and associated factors in the Japanese population: a 3-year follow-up of the ROAD study.

SUMMARY: The prevalence of radiographic cervical ossification of the posterior longitudinal ligament (OPLL) in 1,562 Japanese from a population-based cohort was 1.9 %. The presence of OPLL showed a significant association with the femoral neck bone mineral density (BMD), presence of diffuse idiopathic skeletal hyperostosis (DISH) and plasma pentosidine levels. Only one new case of radiographic OPLL was detected, but OPLL progressed in all affected subjects. INTRODUCTION: The purpose of this study was to clarify the prevalence and progression of radiographic OPLL and the associated factors, using the population-based cohort Research on Osteoarthritis/osteoporosis Against Disability (ROAD). METHODS: In the ROAD study, 1,690 participants underwent X-ray examination of the entire spine and both knees. Radiographic OPLL, lumbar spondylosis, knee osteoarthritis and DISH were diagnosed by a single, well-experienced orthopaedic surgeon. An interviewer-administered questionnaire and tests for anthropometric measurements were administered, and the BMDs of the lumbar spine and proximal femur were determined. A new OPLL case was considered if heterotopic ossification in the posterior longitudinal ligament was absent at baseline but present during follow-up. Progression was defined as an increase in the maximum length or width of the ossification at follow-up over that at baseline. RESULTS: Radiographic OPLL was detected in 30 (17 men, 13 women) of 1,562 individuals who underwent X-ray examination of the cervical spine (prevalence = 1.9 %). Its prevalence was significantly higher in men than in women (p = 0.007), but no association with age was observed. In a logistic regression analysis, OPLL showed a significant association with the femoral neck BMD, presence of DISH and plasma pentosidine levels. Only one new case of radiographic OPLL was detected, but OPLL progressed in all affected subjects. CONCLUSION: This population-based study clarified the prevalence of radiographic OPLL in the Japanese population as well as its progression. OPLL showed significant association with plasma pentosidine levels, BMD and DISH.

Pediatric myxopapillary ependymoma treated with subtotal resection and radiation therapy: a case report and review of the literature.

STUDY DESIGN: Case report and review of the literature. OBJECTIVES: Myxopapillary ependymoma (MPE) is a relatively rare glioma that develops from the spinal part of the filum terminale, usually in adulthood. While it is generally benign, MPE can disseminate intraspinally, and this malignant behavior requires a multidisciplinary response with surgery and radiotherapy. We report here a case of MPE occurring in the lumbosacral spine area of an 8-year-old boy. SETTING: Japan, Tokyo. METHODS: We report here a case of MPE, treated with subtotal surgical resection followed by craniospinal irradiation (CSI), in an 8-year-old boy. The patient was referred to our hospital with a 6-month history of severe pain in the lower back and legs, paralysis of the legs and dysuria. Magnetic resonance imaging images showed a large tumor that filled the entire spinal canal below L1. After subtotal resection of the tumor, the pathological findings established a diagnosis of MPE. Since the tumor had perforated its capsule, increasing the risk of intraspinal dissemination, the patient underwent radiotherapy and CSI after surgery. RESULTS: Magnetic resonance images obtained 3 years after the surgery did not show any recurrence of MPE. CONCLUSION: Although tumor resection followed by CSI can be considered an effective strategy for treating a child with MPE, long-term follow-up is necessary to ensure early detection of any local recurrence or dissemination of the tumor, or of post-radiotherapy scoliosis.

Unique structures of organelles observed in primary spermatocytes after micro-injection of protein solutions such as immunoglobulin into the lumen of the seminiferous tubules in mice and rats.

Unique membranous structures of intracytoplasmic organelle, sting of a stack of a few flat cisternae about 50 nm in thickness, were found in mouse and rat spermatocytes after micro-injection of immunoglobulin G into the lumina of the seminiferous tubules. Other proteins such as BSA and cytochrome c used in this study also induced the structures. In most cases, the stacks of cisternae were rolled up like cigars or cylinders. The structures varied in length and diameter, the largest one observed in this study being 10.7 µm in length. The structures did not appear when the testes were fixed just after micro-injection and were formed transiently: they were observed in the spermatocytes fixed between 1 and 4 h after injection. Cytochrome c, micro-injected as an inter-cellular tracer, was visualised by a diaminobenzidine reaction. As the reaction product was not contained in the cisternae of the unique structures, the lumen of the cisternae of the organelles was not continuous with the inter-cellular space. A flocculent material of low density was observed in the cisternae of the organelle. Similar material was observed in the lumina of solitary cisternae of the rough endoplasmic reticulum in the spermatocytes, suggesting that the structures derived from endoplasmic reticulum.

Molecular epidemiology of meticillin-susceptible Staphylococcus aureus in the neonatal intensive care unit.

BACKGROUND: Staphylococcus aureus - both meticillin-resistant S. aureus (MRSA) and meticillin-susceptible S. aureus (MSSA) - is a major cause of neonatal infections. Infection control measures have not lowered the incidence of MSSA infections to the same degree as that of MRSA infections. AIM: To investigate the transmission pathway of MSSA in neonatal intensive care unit (NICU) using genetic analysis. METHODS: Neonatal patients, their parents, and healthcare workers were swab-tested in the NICU at our hospital at the time of hospitalization and then every month thereafter from October 1st, 2018 to March 31st, 2019. Whole-genome sequencing was performed to test for MSSA strains. Multi-locus sequence typing and single nucleotide polymorphism analysis were used to identify strains and understand their relatedness. FINDINGS: There were 16 MSSA-positive patients. Four MSSA-positive patients shared strains from the same phylogenetic groups as those of healthcare workers. One presented the same strain as the parent. MSSA-positive twin neonates shared the same strain. Ten had sporadic strains; 32 of the 97 tested healthcare workers were MSSA positive. CONCLUSION: The findings of this study suggest that the route of transmission of MSSA in NICU may be through MSSA in the hospital environment in addition to horizontal transmission via healthcare workers. Along with hand hygiene with alcohol, thorough environmental maintenance and parental education are important for infection control in NICUs targeting MSSA.

Localisation of RA175 (Cadm1), a cell adhesion molecule of the immunoglobulin superfamily, in the mouse testis, and analysis of male infertility in the RA175-deficient mouse.

RA175, a member of the immunoglobulin superfamily, plays an important role in cell adhesion, and RA175 gene-deficient mice (RA175(-/-) ) show oligoastheno-teratozoospermia. To understand the function of RA175, location in the testis and the morphological features of its spermatogenic cells in RA175(-/-) mice were investigated. Immunohistochemical studies revealed that RA175 immunoreactivity was observed on the cell surface of the spermatogenic cells at specific stages. A strong reaction was detected from type A spermatogonia to pachytene spermatocytes at stage IV and from step 6 to step 16 spermatids during spermatogenesis. From pachytene spermatocytes at stage VI to step 4 spermatids, the reaction was not detected by the enzyme-labelled antibody method and was faintly detected by the indirect immunofluorescence method. Abnormal vacuoles in the seminiferous epithelium, showing exfoliation of germ cells, and ultrastructural abnormality of the elongate spermatids were revealed in the RA175(-/-) testes. Other members of the immunoglobulin superfamily such as basigin, nectin-2 and nectin-3, which have an important role in spermatogenesis, were immunohistochemically detected in the RA175(-/-) testis. These observations indicate a unique expression pattern of RA175 in the testis and provide clues regarding the mechanism of male infertility in the testis.

Association study of TRAF1-C5 polymorphisms with susceptibility to rheumatoid arthritis and systemic lupus erythematosus in Japanese.

OBJECTIVE: The primary aim of this study was to investigate the association of polymorphisms of TRAF1-C5, a newly identified rheumatoid arthritis (RA) risk locus in Caucasians, with susceptibility to RA and systemic lupus erythematosus (SLE) in Japanese populations. Gene expression levels of TRAF1 and C5 to assess the functional significance of genotypes were also analysed. METHODS: A multicentre association study consisting of 4 RA case-control series (4397 cases and 2857 controls) and 3 SLE case-control series (591 cases and 2199 shared controls) was conducted. Genotyping was performed using TaqMan genotyping assay for two single nucleotide polymorphisms (SNPs) that showed the best evidence of association in the previous Caucasian studies. Quantifications of TRAF1 and C5 expression were performed with TaqMan expression assay. RESULTS: Significant differences in allele frequency for both SNPs were observed between RA and control subjects (combined odds ratio = 1.09), while no significant difference was detected between patients with SLE and controls. Interestingly, alleles rs3761847 A and rs10818488 G had increased the risk for RA in the present study, while they decreased the risk in the original studies. A significant difference was found between risk allele carriers and non-carriers of rs10818488 for the expression level of TRAF1 in phorbol myristate acetate-stimulated lymphoblastoid cell lines (p = 0.04). CONCLUSION: Association of TRAF1-C5 locus with RA susceptibility was detected in the Japanese populations with modest magnitude, while no significant association was observed for SLE. Significant positive effect of genotype on the expression of TRAF1 might support the genetic association between TRAF1 and RA.

GRIP1 enhances estrogen receptor alpha-dependent extracellular matrix gene expression in chondrogenic cells.

OBJECTIVE: The role of postmenopause on the pathogenesis of cartilage degeneration has been an open question. We assessed cartilage degeneration in estrogen receptor (ER)alpha null mice and examined the role of glucocorticoid receptor-interacting protein 1 (GRIP1) in the ERalpha-dependent transcription of a type II collagen gene (col2a1) with special reference to a crosstalk with the transforming growth factor (TGF)-beta signaling pathway. METHODS: The vertebral cartilaginous endplate from female ERalpha null mice was subjected to histological analyses. Col2a1 expression of primary chondrocytes (PCs) obtained from ERalpha null mice after 17beta-estradiol (E(2)) and TGF-beta1 stimulation was examined by reverse transcription polymerase chain reaction (RT-PCR). Estrogen response element (ERE) or col2a1 promoter-enhancer luciferase reporter system was used to investigate the crosstalk among ERalpha, GRIP1, and MKK6. Col2a1 expression and glycosaminoglycan (GAG) content were measured in ATDC5 cells treated with GRIP1 small interfering RNA (siRNA). RESULTS: ERalpha deficiency clearly accelerated impairment of the vertebral cartilaginous endplate. E(2) and TGF-beta1 stimulation increased col2a1 expression in PC from wild-type mice, but not that from ERalpha null mice. The same stimulation increased the col2a1 promoter-enhancer reporter activity, and the elevated activity was decreased by dominant-negative ERalpha and p38 mitogen-activated protein kinase (MAPK) inhibitor. GRIP1 increased the E(2)-dependent ERE activation in the presence of ERalpha and constitutive-active MKK6. GRIP1 siRNA repressed col2a1 expression and GAG production in ATDC5 cells. CONCLUSIONS: Crosstalks between ERalpha/GRIP1 and TGF-beta/MKK6/p38 MAPK pathway have protective roles on cartilage metabolism via regulating the extracellular matrices expression. The finding may lead to the development of a novel therapeutic approach for cartilage degeneration.

Plasma devices to guide and collimate a high density of MeV electrons.

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Microendoscopic resection of lumbar discal cysts.

INTRODUCTION: A lumbar discal cyst is a relatively rare cystic lesion that communicates with lumbar intervertebral discs. Surgical resection of the cyst is the reported treatment of choice. In this study, the authors report the minimally invasive surgical resection of lumbar discal cysts using a microendoscopy. PATIENTS AND METHODS: Seven male patients with lumbar discal cysts underwent microendoscopic resections (mean age: 25.1+/-3.2 years and the mean follow-up period: 27.9 months). During the surgeries, the cysts were subtotally resected in a piecemeal fashion, and the fistulas forming the communications between the cysts and the corresponding intervertebral discs were coagulated using a bipolar coagulator. RESULTS: All the patients obtained relief from their pain after surgery, and no recurrences occurred during a mean follow-up period of 28 months. The mean operation time was 72.6+/-20.2 min, and the mean blood loss was 44.4+/-13.7 grams. No intra- or peri-operative complications were noted in any of the patients. CONCLUSIONS: Microendoscopic resection appears to be a minimally invasive and feasible surgical option for the treatment of lumbar discal cysts.

Hyaluronan inhibits expression of ADAMTS4 (aggrecanase-1) in human osteoarthritic chondrocytes.

BACKGROUND: Intra-articular injection of hyaluronan (HA) has been suggested to have a disease-modifying effect in osteoarthritis, but little is known about the possible mechanisms. OBJECTIVE: To investigate the effects of HA species of different molecular mass, including 800 kDa (HA800) and 2700 kDa (HA2700), on the expression of aggrecanases (ie, ADAMTS species), which play a key role in aggrecan degradation. METHODS: The effects of HA species on the expression of ADAMTS1, 4, 5, 8, 9 and 15 in interleukin 1alpha (IL1alpha)-stimulated osteoarthritic chondrocytes were studied by reverse transcription PCR and real-time PCR. Expression of ADAMTS4 protein and aggrecanase activity and signal transduction pathways of IL1, CD44 and intracellular adhesion molecule 1 (ICAM1) were examined by immunoblotting. RESULTS: IL1alpha treatment of chondrocytes induced ADAMTS4, and HA800 and HA2700 significantly decreased IL1alpha-induced expression of ADAMTS4 mRNA and protein. IL1alpha-stimulated aggrecanase activity in osteoarthritic chondrocytes was reduced by treatment with HA2700 or transfection of small interfering RNA for ADAMTS4. A similar result was obtained when HA2700 was added to explant cultures of osteoarthritic cartilage. HA2700 neither directly inhibited nor bound to ADAMTS4. Downregulation of ADAMTS4 expression by HA2700 was attenuated by treatment of IL1alpha-treated chondrocytes with antibodies to CD44 and/or ICAM1. The increased phosphorylation of IL1 receptor-associated kinase-1 and extracellular signal-regulated protein kinase1/2 induced by the IL1alpha treatment was downregulated by enhanced IRAK-M expression after HA2700 treatment. CONCLUSION: These data suggest that HA2700 suppresses aggrecan degradation by downregulating IL1alpha-induced ADAMTS4 expression through the CD44 and ICAM1 signalling pathways in osteoarthritic chondrocytes.

Ezetimibe improves postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia.

BACKGROUND: Postprandial hyperlipidaemia is known to be a high-risk factor for atherosclerotic disease because of rapid and lasting accumulations of triglyceride-rich lipoproteins and remnants. The Niemann-Pick C1-Like 1 (NPC1L1) protein acts as an intestinal cholesterol transporter and ezetimibe, which inhibits NPC1L1, has been used in patients with hypercholesterolaemia. We investigated effects of ezetimibe on fasting lipid and lipoprotein profiles and postprandial hyperlipidaemia in patients with type IIb hyperlipidaemia. MATERIALS AND METHODS: Ezetimibe 10 mg per day was administered in ten patients with type IIb hyperlipidaemia for 2 months, and lipid and lipoprotein profiles were examined during fasting and after an oral fat loading (OFL) test. RESULTS: In the fasting state, ezetimibe significantly decreased not only total cholesterol, low density lipoprotein (LDL)-cholesterol and apolipoproteinB-100 (apoB-100) levels but triglycerides (TG), apoB-48 and remnant lipoprotein cholesterol (RemL-C) levels. High performance liquid chromatography analysis showed that ezetimibe decreased cholesterol and TG levels in the very low density lipoprotein (VLDL) and LDL size ranges as well as apoB-100 levels, suggesting a decrease in numbers of VLDL and LDL particles. After OFL, ezetimibe decreased the area under the curve for TG, apoB-48 and RemL-C. Ezetimibe decreased postprandial elevations of cholesterol and TG levels in the chylomicrons (CM) size range, suggesting that the postprandial production of CM particles was suppressed by ezetimibe. CONCLUSIONS: These findings suggest that ezetimibe improves fasting lipoprotein profiles and postprandial hyperlipidaemia by suppressing intestinal CM production in patients with type IIb hyperlipidaemia and such treatment may prove to be effective in reducing atherosclerosis.

Redistribution of intermediate filament subunits during skeletal myogenesis and maturation in vitro.

The distribution of intermediate filament (IF) subunits during maturation of skeletal myotubes in vitro was examined by immunofluorescence, using antibodies against two different types of chick IF subunits: (a) 58-kdalton subunits of fibroblasts (anti-58K), and (b) 55-kdalton subunits of smooth muscle (anti-55K). Anti-58K bound to a filament network in replicating presumptive myoblasts and fibroblasts, as well as in immature myotubes. The distribution in immature myotubes was in longitudinal filaments throughout the cytoplasm. With maturation, staining of myotubes by anti-58K diminished and eventually disappeared. Anti-55K selectively stained myotubes, and the fluorescence localization underwent a drastic change in distribution with maturation--from dense, longitudinal filaments in immature myotubes to a cross-striated distribution in mature myotubes that was associated with the I--Z region of myofibrils. However, the emergence of a cross-striated anti-55K pattern did not coincide temperally with the emergence of striated myofibrils, but occurred over a period of days thereafter.

Aberrant quality control in the endoplasmic reticulum impairs the biosynthesis of pulmonary surfactant in mice expressing mutant BiP.

Accumulation of misfolded proteins in the endoplasmic reticulum (ER) induces the unfolded protein response (UPR), which alleviates protein overload in the secretory pathway. Although the UPR is activated under diverse pathological conditions, its physiological role during development and in adulthood has not been fully elucidated. Binding immunoglobulin protein (BiP) is an ER chaperone, which is central to ER function. We produced knock-in mice expressing a mutant BiP lacking the retrieval sequence to cause a defect in ER function without completely eliminating BiP. In embryonic fibroblasts, the UPR compensated for mutation of BiP. However, neonates expressing mutant BiP suffered respiratory failure due to impaired secretion of pulmonary surfactant by alveolar type II epithelial cells. Expression of surfactant protein (SP)-C was reduced and the lamellar body was malformed, indicating that BiP plays a critical role in the biosynthesis of pulmonary surfactant. Because pulmonary surfactant requires extensive post-translational processing in the secretory pathway, these findings suggest that in secretory cells, such as alveolar type II cells, the UPR is essential for managing the normal physiological ER protein overload that occurs during development. Moreover, failure of this adaptive mechanism may increase pulmonary susceptibility to environmental insults, such as hypoxia and ischemia, ultimately leading to neonatal respiratory failure.

A role for the aryl hydrocarbon receptor and the dioxin TCDD in rheumatoid arthritis.

OBJECTIVE: Environmental factors are involved in RA pathogenesis and epidemiological studies have suggested that smoking is an environmental risk factor for RA. The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is one of the major toxic components in cigarettes. To clarify the biological effects of smoking in RA, we investigated the role of TCDD in RA pathogenesis. METHODS: Human synovial tissue was obtained from RA and OA patients and aryl hydrocarbon receptor (AhR) expression in these tissues was evaluated using immunohistochemistry and real-time PCR. Expression of various cytokines was measured by real-time PCR following stimulation of RA synoviocytes with different concentrations of TCDD. To study the role of AhR, we treated RA synoviocytes with alpha-naphthoflavone, a known AhR antagonist. To evaluate which signal transduction pathways were stimulated by the TCDD-AhR interaction, we used inhibitors of nuclear factor-kappaB (NF-kappaB) and extra-cellular stimulus-activated kinase (ERK). RESULTS: Higher AhR mRNA and protein levels were observed in RA synovial tissue than in OA tissue. TCDD up-regulated the expression of IL-1beta, IL-6 and IL-8 through binding to AhR, and this effect was transmitted via the NF-kappaB and ERK signalling cascades. AhR expression in synovial cells was up-regulated by TNF-alpha. CONCLUSION: TNF-alpha activates AhR expression in RA synovial tissue, and that cigarette smoking and exposure to TCDD enhances RA inflammatory processes. TCDD induces inflammatory cytokines via its association with AhR, resulting in stimulation of the NF-kappaB and ERK signalling cascades. Thus TCDD exposure, such as smoking exacerbates RA pathophysiology.

Emergent properties during dorsal closure in Drosophila morphogenesis.

Dorsal closure is an essential stage of Drosophila development that is a model system for research in morphogenesis and biological physics. Dorsal closure involves an orchestrated interplay between gene expression and cell activities that produce shape changes, exert forces and mediate tissue dynamics. We investigate the dynamics of dorsal closure based on confocal microscopic measurements of cell shortening in living embryos. During the mid-stages of dorsal closure we find that there are fluctuations in the width of the leading edge cells but the time-averaged analysis of measurements indicate that there is essentially no net shortening of cells in the bulk of the leading edge, that contraction predominantly occurs at the canthi as part of the process for zipping together the two leading edges of epidermis and that the rate constant for zipping correlates with the rate of movement of the leading edges. We characterize emergent properties that regulate dorsal closure, i.e., a velocity governor and the coordination and synchronization of tissue dynamics.

The Pentax-AWS((R)) rigid indirect video laryngoscope: clinical assessment of performance in 320 cases.

The Pentax-AWS airway scope system is a rigid indirect video laryngoscope with integrated tube guidance. Laryngoscopy and intubation are visualised using a built in LCD monitor which displays the view obtained by a CCD camera mounted in the tip of the laryngoscope. We describe its clinical performance in 320 patients. The Pentax-AWS significantly improved the laryngeal view compared to the Macintosh laryngoscope. Forty-six patients (14%) who were classified as Cormack Lehane glottic view grade 3 or 4 using the Macintosh laryngoscope were classified as grade 1 (45 cases) or 2a (1 case) using the Pentax-AWS airway scope. Laryngeal views measured by percentage of glottic opening score were improved significantly using the Pentax-AWS. Intubation using the Pentax-AWS was successful in all cases, 96% at the first and 4% at the second attempt. The mean (SD) time required to place the tracheal tube was 20 (10) s. The Cormack Lehane grade obtained with the Macintosh blade did not affect the total time to correctly position the tube using the Pentax-AWS. Intubation difficulty scale (score = 0 in 305 patients, score = 1 in 14 and score = 2 in one patient) indicates that tracheal intubation was performed easily in most cases. The Pentax-AWS not only improves the laryngeal view, but its tube guide also facilitates rapid, easy and reliable tracheal intubation under vision. It can be useful in routine anesthesia care and may be advantageous in the situation of unanticipated difficult intubation.

Curettage and allograft reconstruction for giant cell tumours.

PURPOSE: To evaluate treatment outcomes in patients with giant cell tumours after curettage and allograft reconstruction and to identify the risk factors for poor oncological and functional outcome. METHODS: 29 patients with giant cell tumours of bone who underwent curettage and allograft reconstruction were retrospectively reviewed. The adjuvants used were heat treatment by electrocautery and hot water. Types of allograft used, time to bone union, complications, functional outcomes, and risk factors for poor function were analysed. RESULTS: The mean time to bone union was 2.8 (range, 1-5) months. In 7 patients the tumours recurred (6 within 2 years); the 5-year recurrence-free survival rate was 77%. Three recurrences were classified as grade III and 4 as grade II; recurrence and the Campanacci grade showed a trend towards association (p=0.06). Tumour in the distal femur was a risk factor for postoperative fracture (p=0.02). Functional outcomes were excellent in 20 patients, good in 6, fair in 2, and a failure in one. The risk factors for poor function were recurrence (p=0.002) and joint instability (p=0.008) but not the Campanacci grade (p=0.10) or postoperative fracture (p=0.76). Lung metastasis, infection, and non-union were not encountered. CONCLUSION: Despite a relatively high recurrence rate (24%), 26 (90%) of the 29 patients had excellent/good functional outcomes. We recommend the use of adjuvants and allografts for the management of giant cell tumours.

Renal net glucose release in vivo and its contribution to blood glucose in rats.

This study describes the contribution of de novo glucose synthesis by the kidney to blood glucose homeostasis in rats. The net glucose release by the kidney in vivo was measured by an isotope-dilution method, which calculated the extent of dilution of injected [(14)C]glucose by glucose newly synthesized in the kidney. The extent of dilution was determined from the difference between the decrease of the actual blood glucose concentration and that of the radioactivity of [(14)C]glucose, after injecting [(14)C]glucose into functionally hepatectomized rats. The results indicate that the net glucose release by the kidney in vivo in normal fed rats was 0.75+/-0.13 mg/dl per min, and that its contribution to blood glucose was 25.9+/-5.0%. When unilateral nephrectomy was performed, under the same conditions, renal net glucose release was one-half of that in rats with two intact kidneys, which indicates the quantitative accuracy of the isotope-dilution method employed in this study. In rats starved for 24 h, the renal net glucose release increased to 0.99+/-0.08 mg/dl per min. Diabetic rats showed a remarkably higher renal net glucose of 2.28+/-0.33 mg/dl per min, which was 360% of the normal level. Treatment of diabetic rats with insulin, restored the renal net glucose release to the normal level. In acidotic rats, renal net glucose release was as great as 1.03+/-0.15 mg/dl per min, which suggests that the acid-base balance participates in control of renal glucose output. Measurements every 6 h throughout the day showed that glucose was supplied from the kidney at a constant rate without any circadian rhythm. These data suggest that renal gluconeogenesis is of physiological importance in the maintenance of homeostasis of blood glucose.