scholarly journals In situ assessment of the liver microcirculation in mechanically ventilated rats using sidestream dark-field imaging

2009 ◽  
pp. 49-55 ◽  
Author(s):  
V Černý ◽  
Z Turek ◽  
R Pařízková
Keyword(s):  
Animal Studies ◽  
Dark Field ◽  
Target Tissue ◽  
Sidestream Dark Field ◽  
Hepatic Microcirculation ◽  
Midline Laparotomy ◽  
Sdf Imaging ◽  
Liver Microcirculation ◽  
Dark Field Imaging

Assessment of hepatic microcirculation by on-line visualization has been impossible for a long time. Sidestream dark-field (SDF) imaging is a relatively new method allowing direct visualization of both mucosal microcirculation and surface layers microcirculation of solid organs using hand-held probe for direct contact with target tissue. The aim of this study was to evaluate the feasibility of studying the rat hepatic microcirculation in situ by SDF imaging. The liver lobes were left in situ, and images were obtained using SDF imaging on the surface of the liver via upper midline laparotomy. Images were captured intermittently during 10-sec apnoea and recorded. The microvascular parameters were compared with previous validation studies. Clear high contrast SDF images were successfully obtained. Quantitative analysis revealed a mean FSD (functional sinusoidal density) of 402±15 cm/cm2, a sinusoidal diameter of 10.2±0.5 μm and postsinusoidal venular diameter of 33.9±13 μm. SDF imaging is a suitable noninvasive method for accurate quantification of the basic microcirculatory parameters of the liver in situ without a need to exteriorize the liver lobes. This method seems to be applicable in animal studies with possibility to use SDF imaging also intraoperatively, providing unique opportunity to study liver microcirculation during various experimental and clinical settings.

scholarly journals In Situ Assessment of the Brain Microcirculation in Mechanically-Ventilated Rabbits Using Sidestream Dark-Field (SDF) Imaging

2011 ◽  
pp. 75-81 ◽  
Author(s):  
M. ŠITINA ◽  
Z. TUREK ◽  
R. PAŘÍZKOVÁ ◽  
V. ČERNÝ
Keyword(s):  
Dark Field ◽  
Vessel Density ◽  
Flow Index ◽  
Target Tissue ◽  
Cerebral Microcirculation ◽  
Sidestream Dark Field ◽  
Mechanically Ventilated ◽  
Sdf Imaging ◽  
The Brain

Assessment of the cerebral microcirculation by on-line visualization has been impossible for a long time. Sidestream dark-field (SDF) imaging is a relatively new method allowing direct visualization of cerebral surface layer microcirculation using hand-held probe for direct contact with target tissue. The aim of this study was to elucidate the feasibility of studying the cerebral microcirculation in situ by SDF imaging and to assess the basic cerebral microcirculatory parameters in mechanically ventilated rabbits. Images were obtained using SDF imaging from the surface of the brain via craniotomy. Clear high contrast SDF images were successfully obtained. Total small-vessel density was 14.6±1.8 mm/mm2, total all-vessel density was 17.9±1.7 mm/mm2, DeBacker score was 12.0±1.6 mm-1 and microvascular flow index was 3.0±0.0. This method seems to be applicable in animal studies with possibility to use SDF imaging also intraoperatively, providing unique opportunity to study cerebral microcirculation during various experimental and clinical settings.

Nucleation and initial growth of Pd2Si crystals on Si(111)

1993 ◽  
Vol 51 ◽  
pp. 844-845
Author(s):  
Xianghong Tong ◽  
Oliver Pohland ◽  
J. Murray Gibson
Keyword(s):  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Initial Growth ◽  
Surface And Interface ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Initial Stage ◽  
Effect Of Surface

The nucleation and initial stage of Pd2Si crystals on Si(111) surface is studied in situ using an Ultra-High Vacuum (UHV) Transmission Electron Microscope (TEM). A modified JEOL 200CX TEM is used for the study. The Si(111) sample is prepared by chemical thinning and is cleaned inside the UHV chamber with base pressure of 1x10−9 τ. A Pd film of 20 Å thick is deposited on to the Si(111) sample in situ using a built-in mini evaporator. This room temperature deposited Pd film is thermally annealed subsequently to form Pd2Si crystals. Surface sensitive dark field imaging is used for the study to reveal the effect of surface and interface steps.The initial growth of the Pd2Si has three stages: nucleation, growth of the nuclei and coalescence of the nuclei. Our experiments shows that the nucleation of the Pd2Si crystal occurs randomly and almost instantaneously on the terraces upon thermal annealing or electron irradiation.

Can sidestream dark field (SDF) imaging identify subtle microvascular changes of the bowel during colorectal surgery?

2018 ◽  
Vol 22 (10) ◽  
pp. 793-800
Author(s):  
A. F. J. de Bruin ◽  
A. L. M. Tavy ◽  
K. van der Sloot ◽  
A. Smits ◽  
C. Ince ◽  
...  
Keyword(s):  
Colorectal Surgery ◽  
Dark Field ◽  
Sidestream Dark Field ◽  
Sdf Imaging ◽  
Microvascular Changes

Abstract 2044: Selective Head Cooling Initiated during Cpr Induces Post-Resuscitation Carotid Artery Dilation and Increases in Carotid Artery Flow and Cerebral Cortical Microcirculation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Giuseppe Ristagno ◽  
Jun H Cho ◽  
Tao Yu ◽  
Shijie Sun ◽  
Max H Weil ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Common Carotid Artery ◽  
Brain Temperature ◽  
Capillary Density ◽  
Dark Field ◽  
Sidestream Dark Field ◽  
Blood Flows ◽  
Dark Field Imaging ◽  
Head Cooling ◽  
Artery Flow

Introduction. We have previously reported that selective head cooling initiated during CPR prevented increases in brain temperature and improved neurological outcome. In the present study, we explored the relationship between head cooling during CPR and cerebral blood flows. We hypothesized that head cooling during CPR would yield carotid artery dilation with consequent increases in carotid flows and cerebral cortical microcirculation. Methods. Eight pigs weighing 37 ± 1 kg were intubated and mechanically ventilated. The common carotid artery was isolated and a parietal craniotomy was created. Ventricular fibrillation was electrically induced and untreated for 4 min. Animals were then randomized to head cooling or control. Head cooling was initiated with the aid of the RinoChill device (BeneChill Inc) at the beginning of CPR. CPR was performed for 4 min prior to defibrillation. Common carotid artery diameter and flow were assessed with a Doppler transducer. Cerebral cortical capillary density, representing the number of perfused capillaries, was assessed with Sidestream Dark Field imaging (MicroVisionMedical Inc). Brain temperature was measured with a needle sensor inserted in the cerebral cortex. Results. All the animals were resuscitated. After resuscitation, the brain temperature was significantly decreased in animals subjected to head cooling. Significantly greater carotid artery diameters and flows were observed in animals subjected to selective head cooling compared to the control animals. These increases in carotid blood flows were accompanied by significantly greater numbers of perfused capillaries in the cerebral cortices. No differences in cardiac output were observed between the two groups (Table ). Conclusion. Early selective head cooling induces carotid artery dilation and increases in carotid flows and cerebral cortical microcirculation after resuscitation.

Abstract MP61: Evidence of Impaired Microvascular Function a Decade After Delivery in Women With Placental Malperfusion Lesions

Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Alisse Hauspurg ◽  
Judith Brands ◽  
Robin Gandley ◽  
Matthew F Muldoon ◽  
William Tony Parks ◽  
...  
Keyword(s):  
Disease Risk ◽  
Gestational Hypertension ◽  
Boundary Region ◽  
Dark Field ◽  
Endothelial Glycocalyx ◽  
Sidestream Dark Field ◽  
Sublingual Microcirculation ◽  
Dark Field Imaging ◽  
Median Diameter ◽  
History Of

Introduction: Maternal vascular malperfusion (MVM) lesions in the placenta are characterized by incomplete vascular remodeling and vessel features similar to atherosclerosis. MVM lesions indicate a maladaptive maternal vascular response to pregnancy, are often detected in hypertensive disorders of pregnancy (HDP), and may provide a pathologic link to future cardiovascular disease. The endothelial glycocalyx is a glycoprotein-rich layer that is critical for microvascular health and damage may have an important role in the pathophysiology of microcardiovascular disease risk. Hypothesis: We hypothesized that women with malperfusion lesions of the placenta are more likely to evidence microvascular glycocalyx derangement a decade after delivery compared to women without these lesions and that this effect would be most pronounced among women with a history of HDP. Methods: A total of 412 women with placental pathology (N=129 with MVM lesions, N=283 without MVM lesions) were evaluated at 8-10 years postpartum. Placental specimens were reviewed by a blinded perinatal pathologist . HDP (including preeclampsia and gestational hypertension) were abstracted from the medical record. Glycocalyx barrier function was assessed using sublingual sidestream dark field imaging, with reduction defined as deeper penetration of red blood cells (RBCs) into the glycocalyx of the sublingual microcirculation (5-25μm diameter). We compared the median diameter (size) of microvessels, penetration of RBCs into the glycocalyx (perfused boundary region, PBR) and microvascular density (total length of perfused microvessels/mm 2 surface area) in women with and without MVM lesions. Results: Women with placental MVM lesions had smaller-sized sublingual vessels (median 8.59 μM [IQR 8.12, 9.19] vs. 9.01 μM [IQR 8.37, 9.64]; p<0.001), and a lower density of vessels compared to women without lesions. Glycocalyx perfused boundary region was unexpectedly lower in women with MVM lesions (median 2.20 μM [IQR 2.06, 2.43] vs. 2.32 μM [IQR 2.15, 2.50]; p=0.003) in 10-19 μM vessels. Women with HDP and MVM lesions appear to be the most impacted, with the smallest size vessels (median 8.47 [IQR 8.09-9.13]) and the lowest glycocalyx PBR across all vessel sizes. Women with MVM lesions without a HDP similarly had evidence of microvascular glycocalyx derangement whereas women with HDP without placental lesions had a glycocalyx profile similar to women without MVM or a history of HDP. Conclusions: A decade after delivery, women with a history of placental malperfusion lesions had alterations in microvascular perfusion. Women with MVM lesions and a history of HDP appear to be the most severely impacted, which may reflect an underlying maladaptive vascular phenotype detected in the placenta at the time of pregnancy that might provide pathologic insight into future maternal microvascular health.

Formation and Structure of Epitaxial NiSi2 and CoSi2

1981 ◽  
Vol 10 ◽  
Author(s):  
L. J. Chen ◽  
J. W. Mayer ◽  
K. N. Tu
Keyword(s):  
Thin Films ◽  
Dark Field ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Contrast Analysis ◽  
Interfacial Dislocations ◽  
Cobalt Thin Films ◽  
Predicted Values ◽  
Field Imaging

Transmission electron microscopy has been applied to study the formation and structure of epitaxial NiSi2 and CoSi2 thin films on silicon. Bright field and dark field imaging reveal the interface planes of faceted silicides through the strain contrast, analogous to the contrast of the precipitate-matrix interface of coherent or semicoherent precipitates. Superlattice dark field imaging depicts the distribution of twin-related and epitaxial silicides in these systems. { 111 } interfaces were found to be more prominent than {001} interfaces. Twin-related silicides were observed to cover more area on the substrate silicon than epitaxial silicides did.In situ annealing of nickel and cobalt thin films on silicon provides a unique means of investigation of the transformation from polycrystalline to epitaxial silicides. The NiSi2 transformation was found to be very rapid at 820°C, whereas the CoSi2 transformation appeared to be very sluggish. Furnace annealing confirmed that only a small fraction of CoSi2 transforms to epitaxial CoSi2 after annealing at 850°C for 4h.Diffraction contrast analysis has been applied to interfacial dislocations of epitaxial NiSi2/Si and CoSi2/Si systems. The dislocations were found to be of edge type with ⅙<112> and ½<110> Burgers' vectors. The average spacings are close to their respective theoretically predicted values.

scholarly journals Alterations of cerebral microcirculation in peritumoral edema: feasibility of in vivo sidestream dark-field imaging in intracranial meningiomas

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Moncef Berhouma ◽  
Thiebaud Picart ◽  
Chloe Dumot ◽  
Isabelle Pelissou-Guyotat ◽  
David Meyronet ◽  
...  
Keyword(s):  
Mass Effect ◽  
Dark Field ◽  
Sidestream Dark Field ◽  
Reference Pattern ◽  
Who Grade ◽  
Perioperative Morbidity ◽  
Sdf Imaging ◽  
Intracranial Meningiomas ◽  
Normal Reference

Abstract Background Intracranial meningiomas display a variable amount of peritumoral brain edema (PTBE), which can significantly impact perioperative morbidity. The role of microcirculatory disturbances in the pathogenesis of PTBE is still debated. The aim of this study was to microscopically demonstrate and intraoperatively quantify, for the first time, the alterations to microcirculation in PTBE using sidestream dark-field (SDF) imaging. Methods Adult patients with WHO grade I meningiomas were recruited over a 9-month period and divided into 2 groups depending on the absence (NE group) or the presence (E group) of PTBE. In vivo intraoperative microcirculation imaging was performed in the peritumoral area before and after microsurgical resection. Results Six patients were included in the NE group and 6 in the E group. At the baseline in the NE group, there was a minor decrease in microcirculatory parameters compared to normal reference values, which was probably due to the mass effect. In contrast, microcirculatory parameters in the E group were significantly altered, affecting both vessel density and blood flow values, with a drop of approximately 50% of normal values. Surgical resection resulted in a quasi-normalization of microcirculation parameters in the NE group, whereas in the E group, even if all parameters statistically significantly improved, post-resection values remained considerably inferior to those of the normal reference pattern. Conclusion Our study confirmed significant alterations of microcirculatory parameters in PTBE in meningiomas. Further in vivo SDF imaging studies may explore the possible correlation between the severity of these microcirculatory alterations and the postoperative neurological outcome.

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