A case of malignant hypertension with multi-organ injury.

A 33-year-old woman visited our hospital due to visual loss. Her BP was 280/150 mm Hg and pulse rate was 111 beats per minute. A urinalysis showed protein in urine, suggesting kidney injury. A transthoracic echocardiography showed left ventricular hypertrophy. A Cardiac magnetic resonance imaging suggested left ventricular endocardial edema or inflammation. Ophthalmoscopy showed optic disc edema and hard exudates in both eyes. A brain MRI showed multiple high-intensity areas at the pons and white matter of the cerebrum and cerebellum. Although the patient had malignant hypertension, she was successfully treated by medication.

Changes in Sunken Eyes Combined with Blepharoptosis after Levator Resection.

BACKGROUND: This study aims to report the changes in sunken eyes combined with blepharoptosis after levator resection. METHODS: Analysis involved 60 eyes from 32 patients with sunken eyes combined with blepharoptosis. Advancement of the levator aponeurosis and the Müller's muscle complex (levator resection) was performed in these patients. Area of upper eyelid sulcus (AES) was defined as the area of the upper eyelid shadow. The digital images were converted to black and white using image-processing software (Adobe Photoshop), and the AES was calculated using ImageJ software. In addition, margin reflex distance, eyebrow height (EBH), and AES were measured before and 3 months after surgery to assess the changes in the eyelids. RESULTS: Preoperative AES was significantly correlated to age (P < 0.0001; r = 0.8062). Sunken eyes were remarkably improved after levator resection in all patients. Mean margin reflex distance significantly increased, whereas mean EBH and mean AES significantly decreased at 3 months after surgery (P < 0.0001). The AES change was significantly correlated to the EBH change (P < 0.0001; r = 0.5184). CONCLUSIONS: The principal aim of levator resection is to improve upper eyelid height and visual fields; however, this technique can alter the location of the eyebrow and upper orbital fat. The effects fill the hollowness of the upper eyelid and can remarkably improve sunken eyes.

Predictive images of postoperative levator resection outcome using image processing software.

PURPOSE: This study aims to evaluate the efficacy of processed images to predict postoperative appearance following levator resection. METHODS: Analysis involved 109 eyes from 65 patients with blepharoptosis who underwent advancement of levator aponeurosis and Müller's muscle complex (levator resection). Predictive images were prepared from preoperative photographs using the image processing software (Adobe Photoshop®). Images of selected eyes were digitally enlarged in an appropriate manner and shown to patients prior to surgery. RESULTS: Approximately 1 month postoperatively, we surveyed our patients using questionnaires. Fifty-six patients (89.2%) were satisfied with their postoperative appearances, and 55 patients (84.8%) positively responded to the usefulness of processed images to predict postoperative appearance. CONCLUSION: Showing processed images that predict postoperative appearance to patients prior to blepharoptosis surgery can be useful for those patients concerned with their postoperative appearance. This approach may serve as a useful tool to simulate blepharoptosis surgery.

Effects of mechanical stress and vitreous samples in retinal pigment epithelial cells.

In rhegmatogenous retinal detachment (RRD), scattered RPE cells from the basement membrane into the vitreous cavity undergo an epithelial mesenchymal transition (EMT) and form the intraocular fibrous membrane in response to vitreous fluid. We investigated whether exposure to vitreous samples was associated with EMT-associated signals and mesenchymal characters. Human vitreous samples were collected from patients with RRD, epiretinal membrane (ERM), or macular hole (MH). We evaluated the effects of vitreous on ARPE-19 cells in suspension cultures using poly 2-hydroxyethyl methacrylate-coated dishes and three-dimensional (3D) Matrigel cultures. We found that exposure to vitreous samples did not induce morphological changes or accelerate wound closure in monolayers. Several samples showed increased phosphorylation of Smad2 and nuclear translocation of nuclear factor-κB. Mechanical stress triggered an elevation of phosphorylation levels in Smad2. In addition, exposure to vitreous fluid increased the phosphorylation of p38 mitogen-activated protein kinase in cell suspension cultures after mechanical stress. Moreover, ARPE-19 cells showed a stellate invasive phenotype in 3D Matrigel cultures with vitreous samples. In this study, we demonstrated that mechanical stress and vitreous were associated with EMT-associated signals and invasive phenotypes in 3D cultures but not in monolayers. These results have important implications for the role of vitreous humor in the induction of EMT and intraocular fibrosis.

Simultaneous increase in multiple proinflammatory cytokines in the aqueous humor in neovascular glaucoma with and without intravitreal bevacizumab injection.

PURPOSE: To investigate aqueous humor proinflammatory cytokine levels of patients with neovascular glaucoma (NVG), and to analyze the effects of background factors in the expression of these molecules. METHODS: This cross-sectional study enrolled 137 participants who were grouped into (1) primary open-angle glaucoma (POAG; n = 36) patients; (2) NVG patients (NVG; n = 33); and (3) cataract surgery patients as a comparative group (CG; n = 68). Aqueous humor samples were collected from the anterior chamber at the start of surgery, deposited in CryoTubes, registered, and stored at -80 °C until processing. Multiplex microparticle-based immunodetection was performed by using xMAP and the Human Cytokine/Chemokine Panel I. Bevacizumab was injected into the vitreous cavity 1 to 2 days before surgery in 22 NVG patients (IVB group), whereas 11 NVG patients received no antivascular endothelial growth factor (VEGF) therapy 3 months preoperatively (N group). The Wilcoxon rank sum test or Fisher's exact test for two variables and the Tukey-Kramer honestly significant difference test for multiple variables were used to compare the cytokine levels. RESULTS: The NVG patients had higher levels of interleukin (IL)-6, IL-8, monocyte chemotactic protein (MCP)-1, tumor necrosis factor-α (TNF-α), and platelet-derived growth factor (PDGF)-AA compared to both the CG and POAG groups. The levels of IL-6, IL-8, MCP-1, and PDGF-AB/BB were higher in the IVB group than the N group, whereas the VEGF level was significantly lower in the IVB group (P < 0.01). CONCLUSIONS: Intravitreal bevacizumab injection decreased VEGF levels, but not those of the other cytokines.

Frequency and risk factors for neovascular glaucoma after vitrectomy in eyes with proliferative diabetic retinopathy.

PURPOSE: To investigate the rate and risk factors for neovascular glaucoma (NVG) after vitrectomy in proliferative diabetic retinopathy (PDR). METHODS: Five hundred and twelve patients (512 eyes) with PDR who underwent vitrectomy between January 1, 2003 and June 30, 2009 at Kumamoto University Hospital, Japan, were retrospectively evaluated. Postoperative NVG was defined as neovascularization in the anterior segment and intraocular pressure (IOP) ≥ 22 mm Hg after vitrectomy. Kaplan-Meier survival analysis was applied to calculate the rate of NVG after vitrectomy. Risk factors for NVG after vitrectomy were identified by multivariable analysis using the Cox proportional hazards model. RESULTS: The mean follow-up period was 422 days. Twenty-seven of 512 patients (5.3%) developed postoperative NVG after vitrectomy. The probability of NVG occurrence at 6 and 12 months after vitrectomy was 6.0% and 7.1%, respectively. Male sex [relative risk (RR)=4.247; P=0.0032), younger age (RR=0.956/y; P=0.0237), higher baseline IOP (RR=1.203/mm Hg; P=0.0335), preoperative neovascularization in the anterior chamber angle (RR=8.899; P<0.0001), and presence of NVG in the fellow eye (RR=5.355; P=0.0013) were significant risk factors for postoperative NVG. CONCLUSIONS: The frequency of NVG in PDR eyes within 1 year after vitrectomy was estimated as 7.1%. The risk is independently associated with male sex, younger age, higher baseline IOP, preoperative neovascularization in the angle, and NVG in the fellow eye.

Combined intravitreal bevacizumab and trabeculectomy with mitomycin C versus trabeculectomy with mitomycin C alone for neovascular glaucoma.

PURPOSE: To evaluate the effects of intravitreal bevacizumab (IVB) before mitomycin C trabeculectomy (MMCT) for neovascular glaucoma (NVG). METHODS: The study is a retrospective, comparative, consecutive case series. The study group consisted of 57 eyes from 50 patients with NVG who underwent a first MMCT: 33 eyes were treated with MMCT alone between June 1, 2005 and May 17, 2007 (Control Group); and, 24 eyes were treated with a combination of IVB and MMCT after May 18, 2007 (IVB Group). Surgical complications, intraocular pressure (IOP), and the probability of success were compared between the 2 groups. Surgical failure was defined as IOP ≥22 mm Hg for 2 consecutive follow-up visits, a deterioration of visual acuity to no light perception, or additional glaucoma surgeries. RESULTS: There were no significant differences in preoperative data between the groups. Hyphema associated with MMCT occurred significantly less often in the IVB Group (P=0.006). IOPs at 7 and 10 days after MMCT were significantly lower in the IVB Group (P=0.01 and 0.02, respectively). However, Kaplan-Meier survival-curve analysis showed the probability of success 120, 240, and 360 days after MMCT of 87.5%, 79.2%, and 65.2% in the IVB Group, and 75.0%, 71.9%, and 65.3% in the Control Group. No significant difference in survival times was found between the groups (P=0.76). CONCLUSIONS: IVB before MMCT reduced hyphema associated with MMCT for NVG. IVB provided further IOP reduction immediately after MMCT, but did not significantly improve surgical outcomes over longer periods.

Suppression of choroidal neovascularization by N-acetyl-cysteine in mice.

PURPOSE: N-acetyl-cysteine (NAC) is a potent antioxidant known to be a precursor of glutathione. The purpose of this study was to investigate the role of NAC in the development of choroidal neovascularization (CNV). METHODS: CNV was induced in C57BL/6 mice by laser photocoagulation of the ocular fundus. Mice were injected intraperitoneally with NAC or vehicle alone. The levels of 4-hydoroxy-2-nonenal (4-HNE)-modified protein and nucleus factor (NF)-κB were determined by wester blotting. The recruitment of macrophages and neutrophils after laser injury was analyzed immunohistochemically and in myeloperoxidase (MPO) assays. Enzyme-linked immunosorbent assays (ELISA) were used to measure monocyte chemotactic protein (MCP)-1, CXCL1, vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)-1, and VEGFR-2. The extent of CNV was evaluated 7 d after laser injury by lectin staining. RESULTS: In NAC-treated mice with laser-induced injuries, the induction of 4-HNE-modified protein after 3 hr and the activation of NF-κB in nuclear extracts after 6 hr were markedly suppressed compared to vehicle-treated mice. Macrophage and neutrophil recruitment were inhibited and the levels of MCP-1, CXCL1, VEGF, and VEGFR-1 were also lower in NAC-treated mice compared to vehicle-treated mice. Furthermore, the extent of CNV induced was significantly lower in NAC-treated compared to vehicle-treated mice (p = 0.027). CONCLUSIONS: Our results clearly showed that NAC inhibited indicators of oxidative stress and the activation of NF-κB induced by laser injury, and, consequently, suppressed macrophage and neutrophil infiltration and the development of CNV. This suggests novel preventative and interventional therapeutic strategies for age-related macular degeneration.

Involvement of the Hipk family in regulation of eyeball size, lens formation and retinal morphogenesis.

Members of the homeodomain-interacting protein kinase (HIPK) family are involved in various intracellular regulatory mechanisms. The present study focused on clarifying the functions of HIPK family members in ocular organization during late embryogenesis. HIPK1 and HIPK2 were expressed in the inner retina during late embryogenesis. Hipk1(+/-)Hipk2(-/-) mice had a greater frequency of small eyes with a lens deficiency and abnormally laminated and thickened retinas than did wild-type littermates. These data indicate that Hipk1 and Hipk2 are involved in regulation of eye size, lens formation and retinal lamination during late embryogenesis.

Photodynamic therapy alone versus combined with intravitreal bevacizumab for neovascular age-related macular degeneration without polypoidal choroidal vasculopathy in Japanese patients.

BACKGROUND: To compare 12-month results of two single initial treatments--photodynamic therapy with verteporfin alone (PDT group), and this therapy combined with intravitreal bevacizumab (IVB) (COMB group)--for neovascular age-related macular degeneration (AMD), not including patients with polypoidal choroidal vasculopathy (PCV) who were presumed to have AMD. METHODS: This retrospective study evaluated 23 eyes in the PDT group and 22 eyes in the COMB group. IVB (1.25 mg) was administered within 2 weeks after PDT. Main outcome measures were best-corrected visual acuity (VA), central foveal thickness by optical coherence tomography, and number of treatments. RESULTS: At month 12, the PDT group had gained 0.7 letter mean VA and the COMB group, 8.8 letters (P = 0.04). Ten eyes (43%) in the PDT group and 19 eyes (86%) in the COMB group received only one treatment, and significant difference was found (P = 0.005). No severe ocular or systemic safety concerns were discovered. CONCLUSIONS: Our 12-month results of PDT combined with IVB for Japanese patients with AMD without PCV appeared to be more effective than those of PDT alone with fewer treatments.

Retinal astrocyte differentiation mediated by leukemia inhibitory factor in cooperation with bone morphogenetic protein 2.

Retinal astrocytes and their precursor cells migrate from the optic nerve. Interleukin 6 family cytokines, whose signal transduction requires gp130, promote astrocyte differentiation in the optic nerve, though the mechanism of astrocyte differentiation in the retina has not been clarified. We found that GFAP-positive astrocytes were significantly decreased in number but that a considerable number of astrocytes were still present in gp130-deficient mouse retina. These findings suggest that gp130-dependent signaling pathways play essential roles in retinal astrocyte differentiation and that retinal astrocyte differentiation can also be promoted by other signaling pathways. We found that leukemia inhibitory factor, bone morphogenetic proteins, and their receptors are expressed in P0 retina. In addition, leukemia inhibitory factor and bone morphogenetic protein 2 synergistically promote astrocyte differentiation of retinal precursor cells isolated from P0 mouse retina. These observations demonstrated that not only gp130-dependent signaling but also bone morphogenetic proteins play essential roles in retinal astrocyte differentiation.

Suppression of choroidal neovascularization in lectin-like oxidized low-density lipoprotein receptor type 1-deficient mice.

PURPOSE: To elucidate the role of the scavenger receptor, lectin-like oxidized low-density lipoprotein receptor type 1 (LOX-1), in the formation of choroidal neovascularization (CNV). METHODS: CNV was induced by laser photocoagulation of the ocular fundus in mice. The expression of LOX-1 mRNA and protein after laser injury was determined by real-time RT-PCR and Western blot analysis. Gelatin zymography was used to measure the activity of matrix metalloproteinase (MMP)-2 and pro-MMP-9, and ELISA was used to determine monocyte chemoattractant protein (MCP)-1 and vascular endothelial growth factor (VEGF) levels. At 14 days after laser injury, the extent of CNV was evaluated by fluorescein angiography and lectin staining using confocal microscopy. RESULTS: In wild-type mice, the relative expression level of LOX-1 mRNA compared with the control increased significantly 6 hours after laser injury and peaked 12 hours after laser injury (P = 0.011 and P = 0.0006, respectively), and the expression of LOX-1 protein was also detected 1 and 3 days after laser injury. Increases in MMP-2, pro-MMP2, and pro-MMP-9 after laser injury were reduced in LOX-1-deficient mice compared with wild-type mice. At 3 days after laser injury, increases in MCP-1 and VEGF significantly decreased in LOX-1-deficient mice compared with wild-type mice (P = 0.014 and P = 0.001, respectively). Morphometric analyses revealed that the induction of CNV formation was significantly inhibited in LOX-1-deficient mice. CONCLUSIONS: These results suggest that LOX-1 plays an important role in the formation of CNV. This scavenging system might thus be a novel therapeutic target for CNV.

Trabeculectomy with mitomycin C for neovascular glaucoma: prognostic factors for surgical failure.

PURPOSE: To evaluate the prognostic factors for surgical outcomes of trabeculectomy with mitomycin C (MMC) for neovascular glaucoma (NVG). DESIGN: Retrospective cohort study. METHODS: We reviewed the medical records of 101 patients (101 eyes) with NVG treated at Kumamoto University Hospital. The primary endpoint was persistent intraocular pressure > or = 22 mm Hg, deterioration of visual acuity to no light perception, and additional glaucoma procedures. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: The mean follow-up period was 29.3 months (range, 0.5 to 142.3 months). The probability of success 1, 2, and 5 years after trabeculectomy was 62.6%, 58.2%, and 51.7%, respectively. The multivariate model showed that younger age (relative risk [RR], 0.96/year; P = .0007) and previous vitrectomy (RR, 1.62; P = .02) were prognostic factors for surgical failure among all NVG patients. Additionally, an eye with unremoved proliferative membrane and/or unrepaired retinal detachment (RD) after vitrectomy (RR, 1.59; P = .05) was a probable prognostic factor in a subgroup of 66 eyes with previous vitrectomy, and having a fellow eye with NVG (RR, 1.73; P = .003) was a significant prognostic factor in 82 eyes with NVG attributable to diabetic retinopathy. CONCLUSIONS: The prognostic factors for surgical failure of trabeculectomy with MMC for NVG were younger age and previous vitrectomy in all NVG patients, and having a fellow eye with NVG in patients with disease caused by diabetic retinopathy. Persistent proliferative membrane and/or RD after vitrectomy might contribute to poorer outcomes of trabeculectomy.

[Not Available].

We report a case of rubeosis iridis resulting from agenesis of the internal carotid artery. Agenesis of the internal carotid artery is a rare congenital anomaly, and most patients do remain asymptomatic, but we should realize that this condition may lead to ocular ischemic changes, the result being rubeosis iridis.

Pitavastatin: protection against neuronal retinal damage induced by ischemia-reperfusion injury in rats.

PURPOSE: To evaluate the neuroprotective effects of pitavastatin against neuronal retinal damage induced by ischemia-reperfusion injury in rats. METHODS AND RESULTS: Ischemia-reperfusion injury was induced in Sprague-Dawley rats using ocular hypertension. Pitavastatin (0.1, 0.5, or 1.0 mg/kg) was given intravenously 12 hr or 5 min before, or 12 or 24 hr after the induction of ischemia-reperfusion injury. Morphometric and retrograde labeling analyses revealed neuroprotective effects when pitavastatin (0.5 mg/kg) was administered 5 min before--even 12 and 24 hr--after induction of ischemia-reperfusion injury. These effects depended on dose; protection was noted at pitavastatin concentrations of 0.5 and 1 mg/kg but not 0.1 mg/kg. Furthermore, preadministration of pitavastatin (0.5 mg/kg) reduced expression of P-selectin and intercellular adhesion molecule-1 at 12 and 24 hr after induction of ischemia-reperfusion injury. CONCLUSIONS: As pitavastatin was efficacious in preventing retinal neuronal death, it may be a novel therapeutic modality for ischemic retinal diseases.

Autologous plasmin-assisted vitrectomy for stage 5 retinopathy of prematurity: a preliminary trial.

PURPOSE: To evaluate the efficacy of autologous plasmin (AP)-assisted vitrectomy for stage 5 retinopathy of prematurity (ROP). DESIGN: Interventional case series. METHODS: Six consecutive eyes of four children with stage 5 ROP were treated. The patients' ages at the surgery ranged from five to eight months after birth. Four eyes showed closed-closed configuration and two eyes showed open-open configuration. After lensectomy and dissection of the anterior proliferative membrane, 0.03 to 0.22 International Unit (IU) of AP was administrated into the vitreous cavity. After 15 to 30 minutes of incubation, the proliferative membrane was treated. RESULTS: The proliferative membrane was removed successfully without iatrogenic retinal break. Complete reattachment of the posterior pole retina was achieved in all six eyes (100%). No obvious complication was observed in the follow-up period, which ranged from 11 to 14 months. CONCLUSIONS: These results suggest the benefit of AP in the vitrectomy for treatment of stage 5 ROP.

Effect of pitavastatin on experimental choroidal neovascularization in rats.

The association between the use of statins and age-related macular degeneration (AMD), a leading cause of blindness, has been evaluated in many clinical studies; however, the results have been contradictory. We evaluated the effect of pitavastatin administration on laser-induced experimental choroidal neovascularization (CNV) in rats. Brown Norway rats received pitavastatin (1.0mg/kg per day) for 1day prior to laser-induced CNV and continued to receive the drug for 14days. Fluorescein angiograms were graded by masked observers. CNV area and thickness were assessed by fluorescein isothiocyanate-labeled dextran angiography and histology, respectively. Vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (Ccl-2; also known as MCP-1), and intercellular adhesion molecule-1 (ICAM-1) mRNA levels were measured using reverse-transcription polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR. Pitavastatin-treated rats had significantly less fluorescence leakage compared with the vehicle-treated rats estimated by CNV score using fluorescein angiography. Both the area and the thickness of CNV in pitavastatin-treated rats were significantly reduced compared with the vehicle-treated rats. Gene expression of VEGF, Ccl-2, and ICAM-1 were significantly decreased by pitavastatin administration in experimental CNV. Thus, we demonstrated that the therapeutic dose of pitavastatin for human hypocholesterolemia effectively suppressed experimental CNV in rats. The use of pitavastatin may be helpful in preventing CNV development in AMD patients.

Choroidal dye filling velocity in patients with Vogt-Koyanagi-Harada disease.

PURPOSE: To evaluate quantitative choroidal dye filling velocity in patients with Vogt-Koyanagi-Harada disease (VKH) before and after corticosteroid treatment using indocyanine green (ICG) angiography. METHODS: ICG angiography was performed in seven VKH patients before and after systemic corticosteroid treatment. Choroidal dye curves were obtained by image analysis software and analyzed using an exponential model. The model's time constant (tau) was used to evaluate choroidal dye filling velocity. RESULTS: Compared with controls, acute phase choroidal tau values in VKH patients were significantly longer, suggesting choroidal circulation disturbance. During the recovery phase, choroidal tau values were significantly shortened, suggesting choroidal circulatory disturbance improvement. CONCLUSION: Choroidal dye filling velocity may be useful for VKH diagnosis and verification of corticosteroid treatment effectiveness.

Activation of canonical Wnt pathway promotes proliferation of retinal stem cells derived from adult mouse ciliary margin.

Adult retinal stem cells represent a possible cell source for the treatment of retinal degeneration. However, only a small number of stem cells reside in the ciliary margin. The present study aimed to promote the proliferation of adult retinal stem cells via the Wnt signaling pathway. Ciliary margin cells from 8-week-old mice were dissociated and cultured to allow sphere colony formation. Wnt3a, a glycogen synthase kinase (GSK) 3 inhibitor, fibroblast growth factor (FGF) 2, and a FGF receptor inhibitor were then applied in the culture media. The primary spheres were dissociated to prepare either monolayer or secondary sphere cultures. Wnt3a increased the size of the primary spheres and the number of Ki-67-positive proliferating cells in monolayer culture. The Wnt3a-treated primary sphere cells were capable of self-renewal and gave rise to fourfold the number of secondary spheres compared with nontreated sphere cells. These cells also retained their multilineage potential to express several retinal markers under differentiating culture conditions. The Wnt3a-treated cells showed nuclear accumulation of beta-catenin, and a GSK3 inhibitor, SB216763, mimicked the mitogenic activity of Wnt3a. The proliferative effect of SB216763 was attenuated by an FGF receptor inhibitor but was enhanced by FGF2, with Ki-67-positive cells reaching over 70% of the total cells. Wnt3a and SB216763 promoted the proliferation of retinal stem cells, and this was partly dependent on FGF2 signaling. A combination of Wnt and FGF signaling may provide a therapeutic strategy for in vitro expansion or in vivo activation of adult retinal stem cells.

The effect of subtenon triamcinolone acetonide injection for diabetic macular edema on retinal and choroidal circulation.

PURPOSE: To evaluate changes in retinal and choroidal circulation after subtenon triamcinolone acetonide (TA) injection for diabetic macular edema. DESIGN: Prospective interventional case series. METHODS: Thirteen eyes of 13 patients with diabetic macular edema were studied. Fluorescein and indocyanine green angiograms were performed at three periods: before the injection and 1 week and 6 months after subtenon injection of TA (40 mg). Retinal arteriovenous passage time (as an indicator of retinal circulation) and choroidal tau (as an indicator of early filling velocity of choroid) were obtained with image analysis software. RESULTS: Choroidal tau values before and 1 week after subtenon TA injection were, respectively, 3.2 +/- 0.4 and 4.0 +/- 0.7 seconds, which showed a significant delay (P = .01, Wilcoxon signed-rank test). The delayed choroidal tau values returned to pretreatment level at 6 months after TA injection. In contrast, the arteriovenous passage time remained unchanged. CONCLUSION: Subtenon TA injection transiently influences choroidal blood flow.