A novel diagnostic examination for dropped head syndrome (DHS) (Prone position cervical extension test; DHS test).

BACKGROUND: Dropped head syndrome (DHS) is followed by severe cervical extension muscle weakness that results in chin-on chest deformity. However, maintaining a neutral cervical position can be temporarily possible, and the diagnosis of DHS might sometimes be difficult. The purpose of the present study is to examine a novel clinical test (DHS test) as the diagnostic utility for objective evaluation that focuses on cervical extension condition in the prone position. METHODS: One hundred subjects were diagnosed with isolated neck extensor myopathy (INEM)-DHS at our hospital (17 men and 83 women, mean age 75.0 ± 8.5 years), and 62 subjects were enrolled as age-matched controls. The DHS test consisted of three examinations; the first was "Ceiling gazing test" in standing position, the second was horizontal gazing in "Sphinx prone position test", and the third was horizontal gazing in "Hands and knees prone position test". We investigated the sensitivity and specificity of the DHS test for DHS. RESULTS: The patients showing positive in the INEM-DHS group were 63/100 in Ceiling gaze test, 73/100 in the Sphinx prone position test, and 91/100 in the Hands and knees prone position test. In the control group, 0/62 patients presented positive in the Ceiling gaze test, 4/62 in the Sphinx prone position test, and 0/62 in the Hands and knees prone position test. Sensitivity and specificity of the DHS test were 63.0%/100%, 73.0%/93.5%, and 91.0%/100% in the Ceiling gaze test, Sphinx position prone position test, and Hands and knees prone position test, respectively. CONCLUSION: The prone position cervical extension test (DHS test) would be useful as a novel objective diagnostic tool for INEM-DHS.

Intra-aneurysmal embolization of cellulose porous beads to regenerate vessel wall: an experimental study.

PURPOSE: Although the treatment of intracranial cerebral aneurysms with detachable coils is now widely accepted, the problem of coil compaction and recanalization remains unsolved. If the vessel wall can be regenerated at the neck orifice of an aneurysm, thereby reducing the blood flow into the aneurysm, the recurrence rate of the aneurysm would decrease. Accordingly, we aimed to insert cellulose porous beads (CPBs) into rat models of external carotid artery (ECA) aneurysm and study their efficacy in promoting vessel wall regeneration. METHODS: Using a rat aneurysm model, we examined the tissue response to CPBs that were inserted into the ligated ECA sac of rats. The sacs were removed on days 14, 42, 84, and 180 after insertion and subjected to conventional and immunohistochemical examination. We evaluated the tissue response in the ECA sacs and observed the vessel wall regeneration progress. RESULTS: At the neck orifice of the aneurysm in which the CPB was inserted, a layer of regenerating α-smooth muscle actin-positive spindle cells was observed on day 14. The regenerative cell layer gradually thickened until day 42 and, thereafter, the thickness remained unchanged until day 180. A monolayer of factor VIII-positive cells also appeared at the neck orifice on day 14 and covered the entire orifice until day 180. The CPBs were stably localized in the sac without degradation or signs of inflammation. CONCLUSION: CPBs may be promising as embolic materials that can induce stable vessel wall regeneration at the neck orifice of an aneurysm without surrounding inflammatory reactions.

CORRELATIONS BETWEEN CHOROIDAL STRUCTURES AND VISUAL FUNCTIONS IN EYES WITH RETINITIS PIGMENTOSA.

PURPOSE: To investigate the choroidal structures in the enhanced depth imaging optical coherence tomographic images in eyes with retinitis pigmentosa (RP) and to determine correlations between the choroidal structures and visual functions. METHODS: The enhanced depth imaging optical coherence tomographic images of 100 eyes with typical RP and 60 age-, sex-, and axial length-matched normal eyes were binarized using ImageJ. The cross-sectional luminal and stromal areas of the inner and outer subfoveal choroid of 1,500-µm width were measured. The inner choroid included the choriocapillaris and medium vessel layer, and the outer choroid included the larger vessel layer. RESULTS: In the inner choroid, the luminal area and the ratio of luminal/total choroidal area (L/C ratio) were significantly smaller in RP than in controls (P = 0.010, P < 0.001, respectively), whereas the stromal area was not significantly different (P = 0.114). The inner choroidal L/C ratio was significantly correlated with the best-corrected visual acuity, mean deviation, foveal sensitivity, width of the ellipsoid zone, and central foveal thickness in RP after adjusting for the axial length, age, and sex (all P < 0.005). CONCLUSION: The significant correlations between the inner choroidal structures and the visual functions and retinal structures indicate that the choroidal structures are altered in association with the progression of RP.

Inflow hemodynamics evaluated by using four-dimensional flow magnetic resonance imaging and the size ratio of unruptured cerebral aneurysms.

PURPOSE: Prediction of the rupture risk is critical for the identification of unruptured cerebral aneurysms (UCAs) eligible for invasive treatments. The size ratio (SR) is a strong morphological predictor for rupture. We investigated the relationship between the inflow hemodynamics evaluated on four-dimensional (4D) flow magnetic resonance (MR) imaging and the SR to identify specific characteristics related to UCA rupture. METHODS: We evaluated the inflow jet patterns and inflow hemodynamic parameters of 70 UCAs on 4D flow MR imaging and compared them among 23 aneurysms with an SR ≧2.1 and 47 aneurysms with an SR ≦2.0. Based on the shape of inflow streamline bundles with a velocity ≧75% of the maximum flow velocity in the parent artery, the inflow jet patterns were classified as concentrated (C), diffuse (D), neck-limited (N), and unvisualized (U). RESULTS: The incidence of patterns C and N was significantly higher in aneurysms with an SR ≧2.1. The rate of pattern U was significantly higher in aneurysms with an SR ≦2.0. The maximum inflow rate and the inflow rate ratio were significantly higher in aneurysms with an SR ≧2.1. CONCLUSIONS: The SR affected the inflow jet pattern, the maximum inflow rate, and the inflow rate ratio of UCAs. In conjunction with the SR, inflow hemodynamic analysis using 4D flow MR imaging may contribute to the risk stratification for aneurysmal rupture.

Changes of choroidal structure after treatment for primary intraocular lymphoma: retrospective, observational case series.

BACKGROUND: We report changes of choroidal structure determined by binarization of enhanced depth imaging optical coherence tomographic (EDI-OCT) images after treatment for primary intraocular lymphoma (PIOL). METHODS: Five eyes of four patients with PIOL were examined by EDI-OCT before and 6 months after intravitreal methotrexate injections. In addition, 15 eyes of 15 normal individuals controlled by age and refractive error were examined by EDI-OCT. Binarization of the EDI-OCT images was performed using publicly accessible software (ImageJ). The examined area of the subfoveal choroid was 1,500 µm wide, and the dark areas that represented the luminal areas were traced by the Niblack method. Wilcoxon signed rank test was used to determine the significance of changes in the subfoveal choroidal thickness, interstitial area, and luminal area. Mann-Whitney U test was used to compare the parameters in the eyes with pretreatment PIOL and normal control eyes. RESULTS: The subfoveal choroidal thickness was significantly decreased after treatment (P = 0.0431). In the binarized images, the interstitial area was significantly decreased after treatment (P = 0.0431), while the luminal area was not significantly changed (P = 0.8927). After delayed onset of PIOL, increased interstitial area, thickened choroid and unchanged luminal area were observed in one eye. The interstitial area and choroidal thickness were significantly increased in the eyes with pretreatment PIOL compared with the normal control eyes (P = 0.0207, P = 0.0495, respectively), while the luminal area was not significantly different (P = 0.2752). CONCLUSIONS: After treatment for PIOL, the EDI-OCT images showed a thinner choroid, and binarization of the EDI-OCT images showed significantly decreased interstitial areas compared with the luminal areas. The binarized EDI-OCT images can provide useful information on choroidal structure in eyes with PIOL, and combining these images with intraocular interleukin levels or fundus autofluorescence images should provide valuable information for determining the PIOL activity.

Infrared Spectroscopy of Synovial Fluid Shows Accuracy as an Early Biomarker in an Equine Model of Traumatic Osteoarthritis.

Osteoarthritis is a leading cause of lameness and joint disease in horses. A simple, economical, and accurate diagnostic test is required for routine screening for OA. This study aimed to evaluate infrared (IR)-based synovial fluid biomarker profiling to detect early changes associated with a traumatically induced model of equine carpal osteoarthritis (OA). Unilateral carpal OA was induced arthroscopically in 9 of 17 healthy thoroughbred fillies; the remainder served as Sham-operated controls. The median age of both groups was 2 years. Synovial fluid (SF) was obtained before surgical induction of OA (Day 0) and weekly until Day 63. IR absorbance spectra were acquired from dried SF films. Following spectral pre-processing, predictive models using random forests were used to differentiate OA, Sham, and Control samples. The accuracy for distinguishing between OA and any other joint group was 80%. The classification accuracy by sampling day was 87%. For paired classification tasks, the accuracies by joint were 75% for OA vs. OA Control and 70% for OA vs. Sham. The accuracy for separating horses by group (OA vs. Sham) was 68%. In conclusion, SF IR spectroscopy accurately discriminates traumatically induced OA joints from controls.

Nanofluidic analytical system integrated with nanochannel open/close valves for enzyme-linked immunosorbent assay.

There have been significant advances in the field of nanofluidics, and novel technologies such as single-cell analysis have been demonstrated. Despite the evident advantages of nanofluidics, fluid control in nanochannels for complicated analyses is extremely difficult because the fluids are currently manipulated by maintaining the balance of driving pressure. To address this issue, the use of valves will be essential. Our group previously developed a nanochannel open/close valve utilizing glass deformation, but this has not yet been integrated into nanofluidic devices for analytical applications. In the present study, a nanofluidic analytical system integrated with multiple nanochannel open/close valves was developed. This system consists of eight pneumatic pumps, seven nanochannel open/close valves combined with piezoelectric actuators, and an ultra-high sensitivity detector for non-fluorescent molecules. For simultaneous actuation of multiple valves, a device holder was designed that prevented deformation of the entire device caused by operating the valves. A system was subsequently devised to align each valve and actuator with a precision of better than 20 µm to permit the operation of valves. The developed analytical system was verified by analyzing IL-6 molecules using an enzyme-linked immunosorbent assay. Fluid operations such as sample injection, pL-level aliquot sampling and flow switching were accomplished in this device simply by opening/closing specific valves, and a sample consisting of approximately 1500 IL-6 molecules was successfully detected. This study is expected to significantly improve the usability of nanofluidic analytical devices and lead to the realization of sophisticated analytical techniques such as single-cell proteomics.

Plasma and Synovial Fluid Cell-Free DNA Concentrations Following Induction of Osteoarthritis in Horses.

Biomarkers for osteoarthritis (OA) in horses have been extensively investigated, but translation into clinical use has been limited due to cost, limited sensitivity, and practicality. Identifying novel biomarkers that overcome these limitations could facilitate early diagnosis and therapy. This study aimed to compare the concentrations of synovial fluid (SF) and plasma cell-free DNA (cfDNA) over time in control horses with those with induced carpal OA. Following an established model, unilateral carpal OA was induced in 9 of 17 healthy Thoroughbred fillies, while the remainder were sham-operated controls. Synovial fluid and plasma samples were obtained before induction of OA (Day 0) and weekly thereafter until Day 63, and cfDNA concentrations were determined using fluorometry. The SF cfDNA concentrations were significantly higher for OA joints than for sham-operated joints on Days 28 (median 1430 µg/L and 631 µg/L, respectively, p = 0.017) and 63 (median 1537 µg/L and 606 µg/L, respectively, p = 0.021). There were no significant differences in plasma cfDNA between the OA and the sham groups after induction of carpal OA. Plasma cfDNA measurement is not sufficiently sensitive for diagnostic purposes in this induced model of OA. Synovial fluid cfDNA measurement may be used as a biomarker to monitor early disease progression in horses with OA.

Postoperative diabetes insipidus associated with pituitary apoplexy during pregnancy.

BACKGROUND: Pituitary apoplexy during pregnancy is so rare that only 15 cases (12 pituitary adenomas, 2 lymphocytic neurohypophysitis, and 1 normal pituitary gland) have been published to date. Here, we report the case of a pregnant woman presenting with pituitary apoplexy from a nonfunctioning pituitary adenoma and provide a possible mechanism and management option for postoperative diabetes insipidus (DI). CASE PRESENTATION: A 26-year-old woman presented with sudden onset of headache and bitemporal hemianopsia in the 26th week of her first pregnancy. Magnetic resonance imaging clearly revealed an 18 mm pituitary mass with a fluid-fluid level component displacing the optic chiasma upward. Endonasal endoscopic transsphenoidal surgery was successfully carried out 7 days after the onset of symptoms. DI became apparent immediately after the operation and was not controllable by arginine vasopressin (AVP) but by 1-desamino-8-D-arginine vasopressin (DDAVP) instead. This finding suggests an association between DI and vasopressinase secretion from the placenta, because vasopressinase can degrade AVP but not DDAVP. DI had diminished by the time the patient delivered a healthy girl at the 40th week of gestation. CONCLUSION: Postoperative DI associated with pituitary apoplexy during pregnancy should be treated by DDAVP, which is not affected by placental vasopressinase secretion.

Ocular expression of cyclin-dependent kinase 5 in patients with proliferative diabetic retinopathy.

AIMS/INTRODUCTION: Inhibition of peroxisome proliferator-activated receptor gamma (PPARγ) phosphorylation mediated by cyclin-dependent kinase 5 (Cdk5) is one of the main mechanisms of action of antidiabetic drugs. In this study, we analyzed the ocular expression and activation of Cdk5 in patients with proliferative diabetic retinopathy (PDR). MATERIALS AND METHODS: The concentrations of PPARγ, Cdk5 and its activating subunit (p35) were determined in the vitreous body of 24 PDR and 63 control eyes by enzyme-linked immunosorbent assay. In addition, the messenger ribonucleic acid and protein expression levels of PPARγ, Cdk5 and p35 were measured in proliferative neovascular membranes from seven PDR eyes and non-neovascular epiretinal membranes from five control eyes by quantitative real-time polymerase chain reaction and immunohistochemical analysis. RESULTS: PPARγ, Cdk5 and p35 concentrations in the vitreous body were significantly higher in the PDR group compared with the control group. There was also a positive significant correlation of Cdk5 with PPARγ and p35 in the PDR group. Furthermore, the messenger ribonucleic acid expression levels of PPARγ, Cdk5 and p35 in proliferative neovascular membranes were significantly higher in the PDR group compared with the control group. Immunostaining showed increased protein expression levels of PPARγ, Cdk5 and p35 in proliferative neovascular membranes in the PDR group compared with the control group. CONCLUSIONS: Cdk5 activation is involved in PDR pathogenesis through PPARγ expression, and inhibition of Cdk5-mediated PPARγ phosphorylation might be a new therapeutic target for treatment of PDR.

Accelerated protein digestion and separation with picoliter volume utilizing nanofluidics.

Single cell analyses can provide critical biological insight into cellular heterogeneity. In particular, the proteome, which governs cell functions, is much more difficult to analyze because it is principally impossible to amplify proteins compared to nucleic acids. The most promising approach to single cell proteomics is based on the liquid chromatography mass spectrometry (LC-MS) platform. However, pretreatments before MS detection have two critical issues for single cell analysis: analyte loss as a result of adsorption and artifacts due to the duration of analysis. This is a serious problem because single cells have a limited number of protein molecules and a small volume. To solve these issues, we developed an integrated nanofluidic device to manipulate samples on a femtoliter to picoliter (fL-pL) scale to achieve high-throughput analysis via suppressing analyte loss. This device can perform tryptic digestion, chromatographic separation, and non-labeled detection with high consistency. In addition, we introduced an open/close valve by physical deformation of glass on a nanometer scale to independently modify the nanochannel surfaces and control sample aliquots. The injection system equipped with this valve achieved an injection volume of 1.0 ± 0.1 pL. By using this integrated device, we found that the chromatogram of bulk-digestion for 12 hours resembled that of 15 min-digestion in the nanochannel, which indicated that these conditions reached a similar state of digestion. Therefore, an integrated device for ultra-fast protein analysis was developed on a 1 pL scale for the first time.

Effects of epidural morphine on gastrointestinal transit in unmedicated horses.

OBJECTIVE: To evaluate the effect of epidural morphine on gastrointestinal (GI) motility in horses. STUDY DESIGN: Randomly ordered crossover design. ANIMALS: Six healthy adult horses weighing 585± 48 kg (mean±SD). METHODS: Horses were randomly assigned to receive either 0.2 mg kg(-1) morphine or an equal volume (0.04 mL kg(-1)) of saline epidurally (the first inter coccygeal space) with 2 weeks between treatments. The horses were stabled, fed a standardized diet and allowed water ad libitum throughout the duration of the study. Radiopaque spheres were administered by stomach tube. Xylazine 0.2 mg kg(-1) intravenously was administered prior to epidural injection. Heart rate, respiratory rate, GI sounds score and behavior score were recorded before drug administration and after epidural injection at 4, 8, 12, 18, 24 hours and every 12 hours thereafter for 6 days. Feces were weighed, radiographed and the number of spheres counted. Data were analyzed using a mixed effect model. RESULTS: At no time did horses exhibit signs of colic or show significant differences between treatments regarding heart rate, respiratory rate, GI sounds score, behavior score, or cumulative number of spheres. The concentration of spheres per kg of feces was significantly lower (p<0.05) for the morphine group at 18 and 24 hours. Using the centroid of the curves (spheres kg(-1) plotted versus time) the average transit time after saline epidural was 38 hours and after morphine it was 43 hours. The weight of feces hour(-1) was significantly lower (p<0.05) at only 4 and 8 hours after morphine. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural morphine, at a dose of 0.2 mg kg(-1) , temporarily reduced GI motility but did not cause ileus or colic in this small group of healthy unfasted horses. Care should be taken when extrapolating these data to situations in which other factors may also affect GI motility.

Stable Formation of Aqueous/Organic Parallel Two-phase Flow in Nanochannels with Partial Surface Modification.

In microfluidics, various chemical processes can be integrated utilizing parallel multiphase flows. Our group has extended this research to nanofluidics, and recently performed the extraction of lipids using parallel two-phase flow in nanochannels. Although this was achieved in surface-modified nanochannels, a stable condition of parallel two-phase flow remains unknown due to difficulties in device fabrication, for a suitable method of bonding surface-modified substrates is lacking. Therefore, research on parallel two-phase flow in nanochannels has been limited. Herein, a new bonding method which improves the wash process for the substrates and increases the bonding rate to ∼100% is described. The conditions to achieve parallel organic/aqueous two-phase flow were then studied. It was revealed that in nanochannels, higher capillary numbers for the organic phase flow were required compared to that in microchannels. The newly developed fabrication process and flow regimes will contribute to realize integrated nanofluidic devices capable of analyzing single molecules/cells.

Rapid Patient-Side Evaluation of Endothelial Glycocalyx Thickness in Healthy Sedated Cats Using GlycoCheck® Software.

The endothelial glycocalyx (EG) determines transvascular fluid fluxes, and influences inflammation, coagulation, and capillary blood flow. The GlycoCheck® software calculates EG thickness using sidestream dark field videomicroscopy recordings. This method has not been evaluated for use in cats. The aim of the present study was to evaluate the use of GlycoCheck® for estimating EG thickness in healthy cats, and to investigate the variability of EG thickness in this population. One hundred and one healthy research-purposed cats were included in the study. The cats were sedated, and a handheld videomicroscope, connected to GlycoCheck® software, was used to evaluate the sublingual microvasculature. The parameters measured included perfused boundary region (PBR, an indirect measurement of EG thickness) in vessels between 5 and 25 µm in diameter, valid vessel density, percentage red blood cell filling, and median red blood cell column width. Heart rate, respiratory rate, pulse oximetry and oscillometric blood pressure readings were also recorded. There were 35 neutered male cats, 11 intact males, 38 neutered females, and 17 intact females. The average age was 63 months (range, 11-160 months). Tolerance intervals for PBR (vessel diameter 5-25 µm) were 1.89-3.00 µm (95% CI, lower limit 1.76-2.04, upper limit 2.83-3.13 µm); for valid vessel density were 73.33-333.33 µm/mm2 (95% CI, lower limit 77.00-99.33, upper limit 312.67-350.33 µm/mm2); for percentage red blood cell filling were 59.85-85.07% (95% CI, lower limit 58.97-63.33, upper limit 83.07-88.20 %); and for median red blood cell column width were 5.63-8.59 µm (95% CI, lower limit 5.28-6.07, upper limit 8.14-9.51 µm). There was a negative association between median red blood cell column width and body weight (p = 0.007). The median red blood cell column was significantly wider in intact females when compared to spayed females (p = 0.033). The GlycoCheck® analysis was easily performed in healthy sedated cats. Clinical variables did not have an effect on the EG thickness. These results suggest that this technique could be valuable for evaluation of the EG and microvascular parameters in cats.

Changes in choroidal structure following intravitreal aflibercept therapy for retinal vein occlusion.

AIMS: To examine the choroidal change accompanying retinal vein occlusion (RVO) in detail, we measured changes in choroidal structure after intravitreal aflibercept (IVA) injections for RVO using binarisation of enhanced depth imaging optical coherence tomographic (EDI-OCT) images and assessed associations with clinical outcome. METHODS: Retrospective, observational case series. Forty treatment-naïve patients (10 central, 18 major branch and 12 macular branch RVO) were examined by EDI-OCT before and 1, 3 and 6 months after IVA injections. EDI-OCT images were binarised using ImageJ. Subfoveal cross-sectional areas of the luminal, stromal and total choroid over a 1500 µm span were measured and the stromal area to total choroidal area (S/C) ratio was calculated. RESULTS: Compared to normal contralateral eyes, afflicted eyes at baseline exhibited significantly greater stromal area (p<0.001), total choroidal area (p=0.001) and S/C ratio (p<0.001), but no difference in luminal area (p=0.083). The stromal area, S/C ratio and total choroidal area were significantly reduced in afflicted eyes at 1, 3 and 6 months after IVA (all p<0.006). Baseline S/C ratio was significantly correlated with baseline visual acuity (VA), baseline central retinal thickness (CRT) and VA and CRT improvement at 1, 3 and 6 months post-treatment even after adjusting for the axial length, age and sex (all p<0.012). CONCLUSION: RVO induces substantial oedema of the choroidal stromal area that is detectable by binarisation of EDI-OCT images. This stromal oedema likely stems from high intraocular vascular endothelial growth factor levels. Changes in choroidal structure may be used to assess severity and prognosis of RVO.

Suspected Gentamicin-Induced Retinal Vascular Occlusion after Vitrectomy.

Retinal vascular occlusion after ocular surgery is a rare but serious complication. A history of cardiovascular diseases, retrobulbar anesthesia injection, high intraocular pressure during the perioperative period, and drug toxicity have been reported as possible causative factors. We report here two cases of multiple retinal vascular occlusions after the subconjunctival injection of gentamicin at the end of uncomplicated 25-gauge vitrectomy. Case 1 was a 61-year-old man who developed a macular hole in the right eye. Phacovitrectomy with gas tamponade was performed. On postoperative day (POD) 1, dot hemorrhage was observed on the temporal side of the optic disk. On POD10, macular whitening, retinal hemorrhage, and multiple occlusion of retinal arteries and veins were observed. Case 2 was a 51-year-old woman who was diagnosed with rhegmatogenous retinal detachment in the right eye and underwent phacovitrectomy with gas tamponade. On POD3, macular whitening with cotton wool spots and retinal hemorrhage were observed with macular ischemia owing to occlusion of retinal arteries and veins. In both cases, subconjunctival injection of gentamicin given at the end of surgery was the most suspected cause of retinal vascular occlusion.

Quantitative analyses of diameter and running pattern of choroidal vessels in central serous chorioretinopathy by en face images.

This study was to investigate the choroidal vessels in eyes with central serous chorioretinopathy (CSC) quantitatively. We studied 41 CSC eyes and their fellow eyes, and 41 normal eyes of 41 age-adjusted individuals. En-face optical coherence tomography image of the top 25% slab of Haller's layer was analyze. The mean vessel area, vessel length, and vessel diameter were calculated. The running pattern of the vessels was quantified and used to determine the degree of symmetry, the "symmetry index". The vessel area of CSC eyes was not significantly different from that of fellow eyes but significantly larger than that of normal eyes. The vessel length of CSC eyes was not significantly different from fellow eyes but significantly shorter than that of normal eyes. The mean vessel diameter was larger in CSC eyes than in the fellow eyes and the normal eye. The symmetry index was not significantly different in CSC eyes from that of their fellow eyes but was smaller than that of normal eyes. The quantitative analysis showed that eyes with CSC had larger choroidal vessels and asymmetrical vessels running in Haller's layer.

Femtoliter nanofluidic valve utilizing glass deformation.

In the field of micro/nanofluidics, the channel open/close valves are among the most important technologies for switching and partitioning actions and integration of various operations into fluidic circuits. While several types of valves have been developed in microfluidics, few are capable in nanofluidics. In this study, we proposed a femtoliter (fL) volume nanochannel open/close valve fabricated in glass substrates. The valve consists of a shallow, circular and stepped-bottom valve chamber connected to nanochannels and an actuator. Even with tiny deformation occurring at the nanolevel in glass, an open/closed state of a nanochannel (10-1000 nm) can be achieved. We designed a fL-valve based on an analytical material deformation model, and developed a valve fabrication process. We then verified the open/closed state of the valve using a 308 fL-valve chamber with a four-stepped nanostructure fitting an arc-shape of deflected glass, confirmed its stability and durability over 50 open/close operations, and succeeded in stopping/flowing an aqueous solution at 209 fL s-1 under a 100 kPa pressure in a 900 nm nanochannel with a fast response of ∼0.65 s. A leak flow from the closed valve was sufficiently small even at a 490 kPa pressure-driven flow. Since the developed fL-valve can be applied to various nanofluidic devices made of glass and other rigid materials such as plastic, it is expected that this work will contribute significantly to the development of novel integrated micro/nanofluidics chemical systems for use in various applications, such as single cell/single molecule analysis.

Differential effects of N-acetylcysteine on retinal degeneration in two mouse models of normal tension glaucoma.

N-acetylcysteine (NAC) is widely used as a mucolytic agent and as an antidote to paracetamol overdose. NAC serves as a precursor of cysteine and stimulates the synthesis of glutathione in neural cells. Suppressing oxidative stress in the retina may be an effective therapeutic strategy for glaucoma, a chronic neurodegenerative disease of the retinal ganglion cells (RGCs) and optic nerves. Here we examined the therapeutic potential of NAC in two mouse models of normal tension glaucoma, in which excitatory amino-acid carrier 1 (EAAC1) or glutamate/aspartate transporter (GLAST) gene was deleted. EAAC1 is expressed in retinal neurons including RGCs, whereas GLAST is mainly expressed in Müller glial cells. Intraperitoneal administration of NAC prevented RGC degeneration and visual impairment in EAAC1-deficient (knockout; KO) mice, but not in GLAST KO mice. In EAAC1 KO mice, oxidative stress and autophagy were suppressed with increased glutathione levels by NAC treatment. Our findings suggest a possibility that systemic administration of NAC may be available for some types of glaucoma patients.

Investigation of percentage changes in pulse wave transit time induced by mini-fluid challenges to predict fluid responsiveness in ventilated dogs.

OBJECTIVE: To investigate whether percentage changes in pulse wave transit time (PWTT%Δ) induced by mini-fluid challenges predict fluid responsiveness in mechanically ventilated anesthetized dogs. DESIGN: Prospective experimental trial. SETTING: University teaching hospital. ANIMALS: Twelve Harrier hounds. INTERVENTION: Each dog was anesthetized with propofol and isoflurane after premedication with acepromazine, mechanically ventilated, and had a fluid challenge. This was repeated 4 weeks later. The fluid challenge, 10 mL/kg of colloid administration over 13 minutes, consisted of 3 intermittent mini-fluid challenges (1 mL/kg of each over a minute) with a minute interval, and the remaining colloid administration (7 mL/kg) over 7 minutes. MEASUREMENTS AND MAIN RESULTS: Percentage change in velocity time integral of pulmonary arterial flow by echocardiography was calculated as an indication of change in stroke volume. Fluid responsiveness was defined as percentage change in velocity time integral ≥ 15% after 10 mL/kg colloid. Dogs responded on 14 fluid challenges and did not on 10. After 1, 2, 3, and 10 mL/kg of fluid challenge, PWTT%Δ1, 2, 3, 10 were measured. Receiver operator characteristic (ROC) curves were generated and areas under ROC curve were calculated for PWTT%Δ1, 2, 3 . A gray zone approach was used to identify the clinically inconclusive range. The area under the ROC curve for PWTT%Δ3 was 0.91 (P = 0.001). Cutoff value for PWTT%Δ3 was -2.5% (sensitivity: 86%, specificity: 90%). The gray zone for PWTT%Δ3 was identified as between -2.9% to -1.9% for which fluid responsiveness could not be predicted reliably in 6 out of 24 fluid challenges. CONCLUSIONS: In mechanically ventilated anesthetized dogs given a mini-fluid challenge of 3 mL/kg of colloid, PWTT%Δ could predict fluid responsiveness although the gray zone should be considered.