High hydrostatic pressure (30 atm) enhances the apoptosis and inhibits the proteoglycan synthesis and extracellular matrix level of human nucleus pulposus cells via promoting the Wnt/ß-catenin pathway.

Hydrostatic pressure is known to regulate bovine nucleus pulposus cell metabolism, but its mechanism in human nucleus pulposus cells (HNPCs) remains obscure, which attracts our attention and becomes the focus in this study. Specifically, HNPCs were treated with SKL2001 (an agonist in the Wnt/ß-catenin pathway) or XAV-939 (an inhibitor of the Wnt/ß-catenin pathway), and pressurized under the hydrostatic pressure of 1, 3 and 30 atm. The viability, apoptosis and proteoglycan synthesis of treated HNPC were assessed by CCK-8, flow cytometry and radioisotope incorporation assays. The levels of extracellular matrix, Collagen-II, matrix metalloproteinase 3 (MMP3), Wnt-3a and ß-catenin were measured by toluidine blue staining, immunocytochemistry and Western blot. Appropriate hydrostatic stimulation (3 atm) enhanced the viability and proteoglycan synthesis yet inhibited the apoptosis of HNPCs, which also up-regulated extracellular matrix and Collagen-II levels, and down-regulated MMP3, Wnt-3a and ß-catenin levels in treated HNPCs. Furthermore, high hydrostatic pressure (30 atm) inhibited the viability and proteoglycan synthesis, and promoted the morphological change and apoptosis of HNPCs, which also down-regulated extracellular matrix and Collagen-II levels and up-regulated MMP3, Wnt-3a and ß-catenin levels. Besides, SKL2001 reversed the effects of hydrostatic pressure (3 atm) on inhibiting Wnt-3a, ß-catenin, and MMP3 levels and promoting Collagen-II level in HNPC; whereas, XAV-939 reversed the effects of high hydrostatic pressure (30 atm) on promoting MMP3, Wnt-3a, and ß-catenin levels and inhibiting Collagen-II level and proteoglycan synthesis of HNPCs. Collectively, high hydrostatic pressure promoted the apoptosis and inhibited the viability of HNPCs via activating the Wnt/ß-catenin pathway.

Regulation of the Membrane Trafficking of the Mechanosensitive Ion Channels TRPV1 and TRPV4 by Zonular Tension, Osmotic Stress and Activators in the Mouse Lens.

Lens water transport generates a hydrostatic pressure gradient that is regulated by a dual-feedback system that utilizes the mechanosensitive transient receptor potential vanilloid (TRPV) channels, TRPV1 and TRPV4, to sense changes in mechanical tension and extracellular osmolarity. Here, we investigate whether the modulation of TRPV1 or TRPV4 activity dynamically affects their membrane trafficking. Mouse lenses were incubated in either pilocarpine or tropicamide to alter zonular tension, exposed to osmotic stress, or the TRPV1 and TRPV4 activators capsaicin andGSK1016790A (GSK101), and the effect on the TRPV1 and TRPV4 membrane trafficking in peripheral fiber cells visualized using confocal microscopy. Decreases in zonular tension caused the removal of TRPV4 from the membrane of peripheral fiber cells. Hypotonic challenge had no effect on TRPV1, but increased the membrane localization of TRPV4. Hypertonic challenge caused the insertion of TRPV1 and the removal of TRPV4 from the membranes of peripheral fiber cells. Capsaicin caused an increase in TRPV4 membrane localization, but had no effect on TRPV1; while GSK101 decreased the membrane localization of TRPV4 and increased the membrane localization of TRPV1. These reciprocal changes in TRPV1/4 membrane localization are consistent with the channels acting as mechanosensitive transducers of a dual-feedback pathway that regulates lens water transport.

The nitric oxide-cyclic guanosine monophosphate pathway inhibits the bladder ATP release in response to a physiological or pathological stimulus.

The release of ATP from the epithelium of the urinary bladder (urothelium) in response to mechanical/chemical stimuli contributes to the visceral sensation in the micturition reflex. The nitric oxide (NO)-mediated induction of cyclic guanosine monophosphate (cGMP) has been detected in urothelial cells and may inhibit the micturition reflex. However, the function of the NO-cGMP pathway in the regulation of urothelial ATP release remains poorly understood in contrast to its effects on smooth muscles or primary afferent nerves. Therefore, we investigated the relevance of the NO-cGMP pathway to ATP release on the mucosal side in the present study. The administration of l-arginine (NO precursor) or NOC 12 (NO donor) significantly reduced ATP release to the mucosal side at a physiologically normal urine storage pressure (5 cmH2 O). L-NAME (NO synthase inhibitor) significantly increased the distention-induced release of ATP. The phosphodiesterase-5 inhibitor, sildenafil, which increases cGMP levels, inhibited distention-induced ATP release. Furthermore, sildenafil significantly reduced ATP release in response to the administration of lipopolysaccharide. These results suggest that the NO-cGMP pathway inhibited urothelial ATP release during the storage phase under both physiological and pathological conditions.

Pressure-induced changes on the morphology and gene expression in mammalian cells.

We evaluated the effect of high hydrostatic pressure on mouse embryonic fibroblasts (MEFs) and mouse embryonic stem (ES) cells. Hydrostatic pressures of 15, 30, 60, and 90 MPa were applied for 10 min, and changes in gene expression were evaluated. Among genes related to mechanical stimuli, death-associated protein 3 was upregulated in MEF subjected to 90 MPa pressure; however, other genes known to be upregulated by mechanical stimuli did not change significantly. Genes related to cell differentiation did not show a large change in expression. On the other hand, genes related to pluripotency, such as Oct4 and Sox2, showed a twofold increase in expression upon application of 60 MPa hydrostatic pressure for 10 min. Although these changes did not persist after overnight culture, cells that were pressurized to 15 MPa showed an increase in pluripotency genes after overnight culture. When mouse ES cells were pressurized, they also showed an increase in the expression of pluripotency genes. These results show that hydrostatic pressure activates pluripotency genes in mammalian cells. This article has an associated First Person interview with the first author of the paper.

In vitro evaluation of surface biological properties of decellularized aorta for cardiovascular use.

The aim of this study was to determine an in vitro evaluation method that could directly predict in vivo performance of decellularized tissue for cardiovascular use. We hypothesized that key factors for in vitro evaluation would be found by in vitro assessment of decellularized aortas that previously showed good performance in vivo, such as high patency. We chose porcine aortas, decellularized using three different decellularization methods: sodium dodecyl-sulfate (SDS), freeze-thawing, and high-hydrostatic pressurization (HHP). Immunohistological staining, a blood clotting test, scanning electron microscopy (SEM) analysis, and recellularization of endothelial cells were used for the in vitro evaluation. There was a significant difference in the remaining extracellular matrix (ECM) components, ECM structure, and the luminal surface structure between the three decellularized aortas, respectively, resulting in differences in the recellularization of endothelial cells. On the other hand, there was no difference observed in the blood clotting test. These results suggested that the blood clotting test could be a key evaluation method for the prediction of in vivo performance. In addition, evaluation of the luminal surface structure and the recellularization experiment should be packaged as an in vitro evaluation because the long-term patency was probably affected. The evaluation approach in this study may be useful to establish regulations and a quality management system for a cardiovascular prosthesis.

Increased Hydrostatic Pressure Promotes Primary M1 Reaction and Secondary M2 Polarization in Macrophages.

Patients with chronic anterior uveitis are at particularly high risk of developing secondary glaucoma when corticosteroids [e.g., dexamethasone (Dex)] are used or when inflammatory activity has regressed. Macrophage migration into the eye increases when secondary glaucoma develops and may play an important role in the development of secondary glaucoma. Our aim was to evaluate in vitro if increased hydrostatic pressure and corticosteroids could induce changes in macrophages phenotype. By using a pressure chamber cell culture system, we assessed the effect of increased hydrostatic pressure (HP), inflammation, and immunosuppression (Dex) on the M1/M2 phenotype of macrophages. Bone marrow-derived macrophages (BMDMs) were stimulated with medium, lipopolysaccharide (LPS, 100 ng/ml), Dex (200 ng/ml), or LPS + Dex and incubated with different HP (0, 20, or 60 mmHg) for 2 or 7 days. The numbers of CD86+/CD206- (M1 phenotype), CD86-/CD206+ (M2 phenotype), CD86+/CD206+ (intermediate phenotype), F4/80+/TNF-α+, and F4/80+/IL-10+ macrophages were determined by flow cytometry. TNF-α and IL-10 levels in cell culture supernatants were quantified by ELISA. TNF-α, IL-10, fibronectin, and collagen IV expression in BMDMs were detected by immunofluorescence microscopy. Higher HP polarizes macrophages primarily to an M1 phenotype (LPS, 60 vs. 0 mmHg, d2: p = 0.0034) with less extra cellular matrix (ECM) production and secondary to an M2 phenotype (medium, 60 vs. 0 mmHg, d7: p = 0.0089) (medium, 60 vs. 20 mmHg, d7: p = 0.0433) with enhanced ECM production. Dex induces an M2 phenotype (Dex, medium vs. Dex, d2: p < 0.0001; d7: p < 0.0001) with more ECM production. Higher HP further increased M2 polarization of Dex-treated macrophages (Dex, 60 vs. 0 mmHg, d2: p = 0.0417; d7: p = 0.0454). These changes in the M1/M2 phenotype by high HP or Dex treatment may play a role in the pathogenesis of secondary uveitic glaucoma- or glucocorticoid (GC)-induced glaucoma.

Sheath-Preserving Optic Nerve Transection in Rats to Assess Axon Regeneration and Interventions Targeting the Retinal Ganglion Cell Axon.

Retinal ganglion cell (RGC) axons converge at the optic nerve head to convey visual information from the retina to the brain. Pathologies such as glaucoma, trauma, and ischemic optic neuropathies injure RGC axons, disrupt transmission of visual stimuli, and cause vision loss. Animal models simulating RGC axon injury include optic nerve crush and transection paradigms. Each of these models has inherent advantages and disadvantages. An optic nerve crush is generally less severe than a transection and can be used to assay axon regeneration across the lesion site. However, differences in crush force and duration can affect tissue responses, resulting in variable reproducibility and lesion completeness. With optic nerve transection, there is a severe and reproducible injury that completely lesions all axons. However, transecting the optic nerve dramatically alters the blood brain barrier by violating the optic nerve sheath, exposing the optic nerve to the peripheral environment. Moreover, regeneration beyond a transection site cannot be assessed without reapposing the cut nerve ends. Furthermore, distinct degenerative changes and cellular pathways are activated by either a crush or transection injury. The method described here incorporates the advantages of both optic nerve crush and transection models while mitigating the disadvantages. Hydrostatic pressure delivered into the optic nerve by microinjection completely transects the optic nerve while maintaining the integrity of the optic nerve sheath. The transected optic nerve ends are reapposed to allow for axon regeneration assays. A potential limitation of this method is the inability to visualize the complete transection, a potential source of variability. However, visual confirmation that the visible portion of the optic nerve has been transected is indicative of a complete optic nerve transection with 90-95% success. This method could be applied to assess axon regeneration promoting strategies in a transection model or investigate interventions that target the axonal compartments.

TRPV1 activation stimulates NKCC1 and increases hydrostatic pressure in the mouse lens.

The porcine lens response to a hyperosmotic stimulus involves an increase in the activity of an ion cotransporter sodium-potassium/two-chloride cotransporter 1 (NKCC1). Recent studies with agonists and antagonists pointed to a mechanism that appears to depend on activation of transient receptor potential vanilloid 1 (TRPV1) ion channels. Here, we compare responses in lenses and cultured lens epithelium obtained from TRPV1-/- and wild type (WT) mice. Hydrostatic pressure (HP) in lens surface cells was determined using a manometer-coupled microelectrode approach. The TRPV1 agonist capsaicin (100 nM) caused a transient HP increase in WT lenses that peaked after ∼30 min and then returned toward baseline. Capsaicin did not cause a detectable change of HP in TRPV1-/- lenses. The NKCC inhibitor bumetanide prevented the HP response to capsaicin in WT lenses. Potassium transport was examined by measuring Rb+ uptake. Capsaicin increased Rb+ uptake in cultured WT lens epithelial cells but not in TRPV1-/- cells. Bumetanide, A889425, and the Akt inhibitor Akti prevented the Rb+ uptake response to capsaicin. The bumetanide-sensitive (NKCC-dependent) component of Rb+ uptake more than doubled in response to capsaicin. Capsaicin also elicited rapid (<2 min) NKCC1 phosphorylation in WT but not TRPV1-/- cells. HP recovery was shown to be absent in TRPV1-/- lenses exposed to hyperosmotic solution. Bumetanide and Akti prevented HP recovery in WT lenses exposed to hyperosmotic solution. Taken together, responses to capsaicin and hyperosmotic solution point to a functional role for TRPV1 channels in mouse lens. Lack of NKCC1 phosphorylation and Rb+ uptake responses in TRPV1-/- mouse epithelium reinforces the notion that a hyperosmotic challenge causes TRPV1-dependent NKCC1 activation. The results are consistent with a role for the TRPV1-activated signaling pathway leading to NKCC1 stimulation in lens osmotic homeostasis.

Differential Response of Bovine Mature Nucleus Pulposus and Notochordal Cells to Hydrostatic Pressure and Glucose Restriction.

OBJECTIVE: The nucleus pulposus of the human intervertebral disc contains 2 cell types: notochordal (NC) and mature nucleus pulposus (MNP) cells. NC cell loss is associated with disc degeneration and this process may be initiated by mechanical stress and/or nutrient deprivation. This study aimed to investigate the functional responses of NC and MNP cells to hydrostatic pressures and glucose restriction. DESIGN: Bovine MNP and NC cells were cultured in 3-dimensional alginate beads under low (0.4-0.8 MPa) and high (1.6-2.4 MPa) dynamic pressure for 24 hours. Cells were cultured in either physiological (5.5 mM) glucose media or glucose-restriction (0.55 mM) media. Finally, the combined effect of glucose restriction and high pressure was examined. RESULTS: Cell viability and notochordal phenotypic markers were not significantly altered in response to pressure or glucose restriction. MNP cells responded to low pressure with an increase in glycosaminoglycan (GAG) production while high pressure significantly decreased ACAN gene expression compared with atmospheric controls. NC cells showed no response in matrix gene expression or GAG production with either loading regime. Glucose restriction decreased NC cell TIMP-1 expression but had no effect on MNP cells. The combination of glucose restriction and high pressure only affected MNP cell gene expression, with decreased ACAN, Col2α1, and ADAMTS-5 expression. CONCLUSION: This study shows that NC cells are more resistant to acute mechanical stresses than MNP cells and provides a strong rationale for future studies to further our understanding the role of NC cells within the disc, and the effects of long-term exposure to physical stresses.

High hydrostatic pressure induces atrial electrical remodeling through upregulation of inflammatory cytokines.

AIMS: Hypertension is an independent risk factor for atrial fibrillation (AF). However, the direct effect of hydrostatic pressure on atrial electrical remodeling is unclear. The present study investigated whether hydrostatic pressure is responsible for atrial electrical remodeling and addressed a potential role of inflammation in this pathology. MAIN METHODS: Whole-cell patch-clamp recordings and biochemical assays were used to study the regulation and expression of ion channels in left atrial appendages in patients with AF, spontaneously hypertensive rats (SHRs), and atrium-derived cells (HL-1 cells) exposed to standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure. KEY FINDINGS: Both TNF-α and MIF were highly expressed in patients with AF and SHRs. AF inducibility in SHRs was higher after atrial burst pacing, accompanied by a decrease in the L-type calcium current (ICa,L), an increase in the transient outward K+ current (Ito) and ultra-rapid delayed rectifier K+ current (IKur), and a shortened action potential duration (APD), which could be inhibited by atorvastatin. Furthermore, exposure to elevated pressure was associated with electrical remodeling of the HL-1 cells. The peak current density of ICa,L was reduced, while Ito and IKur were increased. Moreover, the expression levels of Kv4.3, Kv1.5, TNF-α, and MIF were upregulated, while the expression of Cav1.2 was downregulated in HL-1 cells after treatment with high hydrostatic pressure (40 mmHg). Atorvastatin alleviated the electrical remodeling and increased inflammatory markers in HL-1 cells induced by high hydrostatic pressure. SIGNIFICANCE: Elevated hydrostatic pressure led to atrial electrical remodeling and increased AF susceptibility by upregulating inflammation.

Ribosome Reconstruction during Recovery from High-Hydrostatic-Pressure-Induced Injury in Bacillus subtilis.

Vegetative cells of Bacillus subtilis can recover from injury after high-hydrostatic-pressure (HHP) treatment at 250 MPa. DNA microarray analysis revealed that substantial numbers of ribosomal genes and translation-related genes (e.g., translation initiation factors) were upregulated during the growth arrest phase after HHP treatment. The transcript levels of cold shock-responsive genes, whose products play key roles in efficient translation, and heat shock-responsive genes, whose products mediate correct protein folding or degrade misfolded proteins, were also upregulated. In contrast, the transcript level of hpf, whose product (Hpf) is involved in ribosome inactivation through the dimerization of 70S ribosomes, was downregulated during the growth arrest phase. Sucrose density gradient sedimentation analysis revealed that ribosomes were dissociated in a pressure-dependent manner and then reconstructed. We also found that cell growth after HHP-induced injury was apparently inhibited by the addition of Mn2+ or Zn2+ to the recovery medium. Ribosome reconstruction in the HHP-injured cells was also significantly delayed in the presence of Mn2+ or Zn2+ Moreover, Zn2+, but not Mn2+, promoted dimer formation of 70S ribosomes in the HHP-injured cells. Disruption of the hpf gene suppressed the Zn2+-dependent accumulation of ribosome dimers, partially relieving the inhibitory effect of Zn2+ on the growth recovery of HHP-treated cells. In contrast, it was likely that Mn2+ prevented ribosome reconstruction without stimulating ribosome dimerization. Our results suggested that both Mn2+ and Zn2+ can prevent ribosome reconstruction, thereby delaying the growth recovery of HHP-injured B. subtilis cells.IMPORTANCE HHP treatment is used as a nonthermal processing technology in the food industry to inactivate bacteria while retaining high quality of foods under suppressed chemical reactions. However, some populations of bacterial cells may survive the inactivation. Although the survivors are in a transient nongrowing state due to HHP-induced injury, they can recover from the injury and then start growing, depending on the postprocessing conditions. The recovery process in terms of cellular components after the injury remains unclear. Transcriptome analysis using vegetative cells of Bacillus subtilis revealed that the translational machinery can preferentially be reconstructed after HHP treatment. We found that both Mn2+ and Zn2+ prolonged the growth-arrested stage of HHP-injured cells by delaying ribosome reconstruction. It is likely that ribosome reconstruction is crucial for the recovery of growth ability in HHP-injured cells. This study provides further understanding of the recovery process in HHP-injured B. subtilis cells.

Endothelial cell Piezo1 mediates pressure-induced lung vascular hyperpermeability via disruption of adherens junctions.

Increased pulmonary microvessel pressure experienced in left heart failure, head trauma, or high altitude can lead to endothelial barrier disruption referred to as capillary "stress failure" that causes leakage of protein-rich plasma and pulmonary edema. However, little is known about vascular endothelial sensing and transduction of mechanical stimuli inducing endothelial barrier disruption. Piezo1, a mechanosensing ion channel expressed in endothelial cells (ECs), is activated by elevated pressure and other mechanical stimuli. Here, we demonstrate the involvement of Piezo1 in sensing increased lung microvessel pressure and mediating endothelial barrier disruption. Studies were made in mice in which Piezo1 was deleted conditionally in ECs (Piezo1iΔEC ), and lung microvessel pressure was increased either by raising left atrial pressure or by aortic constriction. We observed that lung endothelial barrier leakiness and edema induced by raising pulmonary microvessel pressure were abrogated in Piezo1iΔEC mice. Piezo1 signaled lung vascular hyperpermeability by promoting the internalization and degradation of the endothelial adherens junction (AJ) protein VE-cadherin. Breakdown of AJs was the result of activation of the calcium-dependent protease calpain and degradation of the AJ proteins VE-cadherin, ß-catenin, and p120-catenin. Deletion of Piezo1 in ECs or inhibition of calpain similarly prevented reduction in the AJ proteins. Thus, Piezo1 activation in ECs induced by elevated lung microvessel pressure mediates capillary stress failure and edema formation secondary to calpain-induced disruption of VE-cadherin adhesion. Inhibiting Piezo1 signaling may be a useful strategy to limit lung capillary stress failure injury in response to elevated vascular pressures.

Management of industrial high-pressure fluid injection injuries (IHPFII): the Water Jetting Association (WJA) experience with water driven injuries.

BACKGROUND: Industrial high-pressure fluid injection injuries (IHPFII) are largely occupational in nature, where these injuries are most often sustained by male manual workers. Such traumatic injuries are largely sustained with water, grease, paint, gasoline or paint thinner. IHPFII are extremely serious injuries with life and limb-threatening potential carrying the risk of life-long disability. METHODS: We reviewed the Water Jetting Association© adverse incident database of advisory alerts detailing cases from around the world that have been brought to the association's attention and the English-language literature on high-pressure hydrostatic injuries from 1937 to 2018. RESULTS: Accidents involving high-pressure water jets in the industry are uncommon. The clinical impact in all of the cases reviewed and the effects of water jet impacts range from instant fatalities at scene to loss of limb function and amputation. The majority of observed fatalities are due to major hemorrhage (exsanguination) secondary to the direct dissection of great vessels or high-energy blunt soft tissue injury and traumatic brain injury. CONCLUSIONS: As with any other trauma, IHPWJI commonly result in amputation or death. Nonetheless, a lack of comprehension of the potential severity of injuries and range of infective complications appears to be largely due to the apparent benignity of the initial presentation of the wound. This in turn leads to delays (both avoidable and unavoidable) in the transfer to appropriate medical facilities and definitive care. There is an identifiable need for education (including for health care providers across multiple levels), training and the availability of personal trauma kits for the timely and effective management of IHPWJI from the initial jet impact on the scene, as well as a need for an established referral system.

Structural stability of human butyrylcholinesterase under high hydrostatic pressure.

Human butyrylcholinesterase is a nonspecific enzyme of clinical, pharmacological and toxicological significance. Although the enzyme is relatively stable, its activity is affected by numerous factors, including pressure. In this work, hydrostatic pressure dependence of the intrinsic tryptophan fluorescence in native and salted human butyrylcholinesterase was studied up to the maximum pressure at ambient temperature of about 1200 MPa. A correlated large shift toward long wavelengths and broadening observed at pressures between 200 and 700 MPa was interpreted as due to high pressure-induced denaturation of the protein, leading to an enhanced exposure of tryptophan residues into polar solvent environment. This transient process in native butyrylcholinesterase presumably involves conformational changes of the enzyme at both tertiary and secondary structure levels. Pressure-induced mixing of emitting local indole electronic transitions with quenching charge transfer states likely describes the accompanying fluorescence quenching that reveals different course from spectral changes. All the pressure-induced changes turned irreversible after passing a mid-point pressure of about 400 ±â€¯50 MPa. Addition of either 0.1 M ammonium sulphate (a kosmotropic salt) or 0.1 M lithium thiocyanate (a chaotropic salt) to native enzyme similarly destabilized its structure.

Hydrostatic pressure-generated reactive oxygen species induce osteoarthritic conditions in cartilage pellet cultures.

Osteoarthritis (OA) is one of the most common causes of disability and represents a major socio-economic burden. Despite intensive research, the molecular mechanisms responsible for the initiation and progression of OA remain inconclusive. In recent years experimental findings revealed elevated levels of reactive oxygen species (ROS) as a major factor contributing to the onset and progression of OA. Hence, we designed a hydrostatic pressure bioreactor system that is capable of stimulating cartilage cell cultures with elevated ROS levels. Increased ROS levels in the media did not only lead to an inhibition of glycosaminoglycans and collagen II formation but also to a reduction of already formed glycosaminoglycans and collagen II in chondrogenic mesenchymal stem cell pellet cultures. These effects were associated with the elevated activity of matrix metalloproteinases as well as the increased expression of several inflammatory cytokines. ROS activated different signaling pathways including PI3K/Akt and MAPK/ERK which are known to be involved in OA initiation and progression. Utilizing the presented bioreactor system, an OA in vitro model based on the generation of ROS was developed that enables the further investigation of ROS effects on cartilage degradation but can also be used as a versatile tool for anti-oxidative drug testing.

Diagnosing and managing common genital emergencies in pediatric girls.

The presentation of genital injuries and emergencies in pediatric girls can sometimes be misleading. A traumatic injury with excessive bleeding may be a straddle injury that requires only conservative management, while a penetrating injury may have no recognizable signs or symptoms but require extensive surgery. This issue reviews the most common traumatic genital injuries in girls presenting to the emergency department, including straddle injuries, hematomas, and impalement injuries. Nontraumatic emergencies, including hematocolpos and urethral prolapse, are also discussed. Evidence-based recommendations are presented for identifying and managing these common genital injuries and emergencies in pediatric girls.

A Case of a Ruptured Eyeball Caused by High-Pressure Water Jets.

To report the case of a ruptured eyeball caused by high-pressure water jets. In this study, the right eye of a 49-year-old male was injured by high-pressure water jets while he was engaged in demolition work. Upon examination, remarkable hyphema and vitreous hemorrhage were observed in the injured eye. After treating the patient's right eye with vitrectomy, in addition to lens subluxation and iridodialysis, retinal detachment was observed at the nasal inferior. The edge of the retinal break was found to be incarcerated into the nasal sclera rupture wounds. The findings of this study indicate that direct exposure to high-pressure water jets can cause a rupture of the eyeball. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:451-455.].

Piezo1 is a mechanically activated ion channel and mediates pressure induced pancreatitis.

Merely touching the pancreas can lead to premature zymogen activation and pancreatitis but the mechanism is not completely understood. Here we demonstrate that pancreatic acinar cells express the mechanoreceptor Piezo1 and application of pressure within the gland produces pancreatitis. To determine if this effect is through Piezo1 activation, we induce pancreatitis by intrapancreatic duct instillation of the Piezo1 agonist Yoda1. Pancreatitis induced by pressure within the gland is prevented by a Piezo1 antagonist. In pancreatic acinar cells, Yoda1 stimulates calcium influx and induces calcium-dependent pancreatic injury. Finally, selective acinar cell-specific genetic deletion of Piezo1 protects mice against pressure-induced pancreatitis. Thus, activation of Piezo1 in pancreatic acinar cells is a mechanism for pancreatitis and may explain why pancreatitis develops following pressure on the gland as in abdominal trauma, pancreatic duct obstruction, pancreatography, or pancreatic surgery. Piezo1 blockade may prevent pancreatitis when manipulation of the gland is anticipated.

Glacier protection laws: Potential conflicts in managing glacial hazards and adapting to climate change.

The environmental, socioeconomic and cultural significance of glaciers has motivated several countries to regulate activities on glaciers and glacierized surroundings. However, laws written to specifically protect mountain glaciers have only recently been considered within national political agendas. Glacier Protection Laws (GPLs) originate in countries where mining has damaged glaciers and have been adopted with the aim of protecting the cryosphere from harmful activities. Here, we analyze GPLs in Argentina (approved) and Chile (under discussion) to identify potential environmental conflicts arising from law restrictions and omissions. We conclude that GPLs overlook the dynamics of glaciers and could prevent or delay actions needed to mitigate glacial hazards (e.g. artificial drainage of glacial lakes) thus placing populations at risk. Furthermore, GPL restrictions could hinder strategies (e.g. use of glacial lakes as reservoirs) to mitigate adverse impacts of climate change. Arguably, more flexible GPLs are needed to protect us from the changing cryosphere.

Optimization of Extracellular Matrix Synthesis and Accumulation by Human Articular Chondrocytes in 3-Dimensional Construct with Repetitive Hydrostatic Pressure.

Objective The effects of hydrostatic pressure (HP) on the matrix synthesis by human articular chondrocytes have been reported elsewhere. In order to optimize the production of extracellular matrix, we aimed to clarify the effects of repetitive HP on metabolic function by human articular chondrocytes. Design The human articular chondrocytes were expanded and embedded within a collagen gel/sponge scaffold. We incubated these constructs with and without HP followed by atmospheric pressure (AP) and repeated the second HP followed by AP over 14 days. Genomic, biochemical, and histological evaluation were performed to compare the effects of each regimen on the constructs. Results The gene expressions of collagen type II and aggrecan core protein were significantly upregulated with repetitive HP regimens compared with a single HP or AP by 14 days ( P < 0.01 or 0.05). Matrix metalloptoteinase-13 (MMP-13) in AP was upregulated significantly compared to other HP regimens at day 14 ( P < 0.01). No significant difference was observed in tissue inhibitor of metalloproteinases-II. Immunohistology demonstrated that application of HP (both repetitive and single) promoted the accumulation of specific extracellular matrix and reduced a MMP-13. A single regimen of HP followed by AP significantly increased the amount of sulfated glycosaminoglycan than that of the AP, whereas repetitive HP remained similar level of that of the AP. Conclusions Repetitive HP had a greater effect on anabolic activity by chondrocytes than a single HP regimen, which will be advantageous for producing a matrix-rich cell construct.