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Bernier-Latmani J, González-Loyola A, Petrova TV. Mechanisms and functions of intestinal vascular specialization. J Exp Med 2024; 221:e20222008. [PMID: 38051275 PMCID: PMC10697212 DOI: 10.1084/jem.20222008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023] Open
Abstract
The intestinal vasculature has been studied for the last 100 years, and its essential role in absorbing and distributing ingested nutrients is well known. Recently, fascinating new insights into the organization, molecular mechanisms, and functions of intestinal vessels have emerged. These include maintenance of intestinal epithelial cell function, coping with microbiota-induced inflammatory pressure, recruiting gut-specific immune cells, and crosstalk with other organs. Intestinal function is also regulated at the systemic and cellular levels, such that the postprandial hyperemic response can direct up to 30% of systemic blood to gut vessels, while micron-sized endothelial cell fenestrations are necessary for nutrient uptake. In this review, we will highlight past discoveries made about intestinal vasculature in the context of new findings of molecular mechanisms underpinning gut function. Such comprehensive understanding of the system will pave the way to breakthroughs in nutrient uptake optimization, drug delivery efficiency, and treatment of human diseases.
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Affiliation(s)
- Jeremiah Bernier-Latmani
- Department of Oncology, University of Lausanne and Ludwig Institute for Cancer Research Lausanne, Lausanne, Switzerland
| | | | - Tatiana V. Petrova
- Department of Oncology, University of Lausanne and Ludwig Institute for Cancer Research Lausanne, Lausanne, Switzerland
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
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2
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Takeuchi H, Yamamoto Y, Miyahara J, Takeshima T, Ozaki A, Kawasaki T, Kawamura K, Oka N. Small vessel platelet thrombosis in the peripheral nerves in POEMS syndrome. Muscle Nerve 2023; 68:882-885. [PMID: 37837287 DOI: 10.1002/mus.27986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/15/2023]
Abstract
INTRODUCTION/AIMS Vascular thrombosis is prevalent among patients with polyneuropathy, organomegaly, endocrinopathy M-protein, and skin changes (POEMS) syndrome. The endothelial cells in the endoneurium are often hypertrophied and the lumen is frequently occluded. Consequent local hypoxia may increase vascular endothelial growth factor (VEGF), which induces hypercoagulation and vascular permeability. METHODS This study presents two patients in the fifth decade of life, who had rare nerve biopsy findings of vascular occlusion mainly by platelets. Before the cases presented here, we encountered nine confirmed POEMS patients whose nerve biopsies did not show similar findings. RESULTS A small artery and a vein were occluded, but no atherosclerotic changes were observed. The endothelial cells that adhered to the packed platelets lost their junctions. DISCUSSION Platelet aggregation, degranulation, and ischemia may cause a loose endothelial barrier and leak proinflammatory cytokines, such as interleukin-12. This may increase production of VEGF and may cause nerve demyelination. Small vessel platelet thrombosis may contribute to the pathogenesis of this disorder.
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Affiliation(s)
- Hiroki Takeuchi
- Department of Neurology, NHO Minami-Kyoto Hospital, Kyoto, Japan
| | | | | | | | - Akihiko Ozaki
- Department of Neurology, Osaka Red Cross Hospital, Osaka, Japan
| | | | | | - Nobuyuki Oka
- Department of Neurology, NHO Minami-Kyoto Hospital, Kyoto, Japan
- Kyoto Konoe Rehabilitation Hospital, Kyoto, Japan
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3
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Bernier-Latmani J, Mauri C, Marcone R, Renevey F, Durot S, He L, Vanlandewijck M, Maclachlan C, Davanture S, Zamboni N, Knott GW, Luther SA, Betsholtz C, Delorenzi M, Brisken C, Petrova TV. ADAMTS18 + villus tip telocytes maintain a polarized VEGFA signaling domain and fenestrations in nutrient-absorbing intestinal blood vessels. Nat Commun 2022; 13:3983. [PMID: 35810168 PMCID: PMC9271081 DOI: 10.1038/s41467-022-31571-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/21/2022] [Indexed: 12/17/2022] Open
Abstract
The small intestinal villus tip is the first point of contact for lumen-derived substances including nutrients and microbial products. Electron microscopy studies from the early 1970s uncovered unusual spatial organization of small intestinal villus tip blood vessels: their exterior, epithelial-facing side is fenestrated, while the side facing the villus stroma is non-fenestrated, covered by pericytes and harbors endothelial nuclei. Such organization optimizes the absorption process, however the molecular mechanisms maintaining this highly specialized structure remain unclear. Here we report that perivascular LGR5+ villus tip telocytes (VTTs) are necessary for maintenance of villus tip endothelial cell polarization and fenestration by sequestering VEGFA signaling. Mechanistically, unique VTT expression of the protease ADAMTS18 is necessary for VEGFA signaling sequestration through limiting fibronectin accumulation. Therefore, we propose a model in which LGR5+ ADAMTS18+ telocytes are necessary to maintain a “just-right” level and location of VEGFA signaling in intestinal villus blood vasculature to ensure on one hand the presence of sufficient endothelial fenestrae, while avoiding excessive leakiness of the vessels and destabilization of villus tip epithelial structures. The molecular mechanisms ensuring the specialized structure of small intestinal villus tip blood vessels are incompletely understood. Here the authors show that ADAMTS18+ telocytes maintain a “just-right” level and location of VEGFA signaling on intestinal villus blood vessels, thereby ensuring the presence of endothelial fenestrae for nutrient absorption, while avoiding excessive leakiness and destabilization of villus tip epithelial structures.
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Affiliation(s)
- Jeremiah Bernier-Latmani
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne and University of Lausanne, Lausanne, Switzerland.
| | - Cristina Mauri
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne and University of Lausanne, Lausanne, Switzerland
| | - Rachel Marcone
- Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - François Renevey
- Department of Immunobiology, University of Lausanne, Lausanne, Switzerland
| | - Stephan Durot
- Institute of Molecular Systems Biology ETH, Zurich, Switzerland
| | - Liqun He
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Michael Vanlandewijck
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.,Department of Medicine-Huddinge, Karolinska Institutet, Huddinge, Sweden
| | - Catherine Maclachlan
- Bio Electron Microscopy Laboratory, School of Life Sciences, EPFL, Lausanne, Switzerland
| | - Suzel Davanture
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne and University of Lausanne, Lausanne, Switzerland
| | - Nicola Zamboni
- Institute of Molecular Systems Biology ETH, Zurich, Switzerland
| | - Graham W Knott
- Bio Electron Microscopy Laboratory, School of Life Sciences, EPFL, Lausanne, Switzerland
| | - Sanjiv A Luther
- Department of Immunobiology, University of Lausanne, Lausanne, Switzerland
| | - Christer Betsholtz
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.,Department of Medicine-Huddinge, Karolinska Institutet, Huddinge, Sweden
| | - Mauro Delorenzi
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne and University of Lausanne, Lausanne, Switzerland.,Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Cathrin Brisken
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, EPFL, Lausanne, Switzerland
| | - Tatiana V Petrova
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne and University of Lausanne, Lausanne, Switzerland. .,Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, EPFL, Lausanne, Switzerland.
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Gotloib L, Shustack A. Ultrastructural Morphology of the Peritoneum: New Findings and Speculations on Transfer of Solutes and Water during Peritoneal Dialysis. Perit Dial Int 2020. [DOI: 10.1177/089686088700700304] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Lazaro Gotloib
- From the Dept. of Nephrology and the Kornach Lab. for Experimental Nephrology. Central Emek Hospital, Afula Israel
| | - A. Shustack
- From the Dept. of Nephrology and the Kornach Lab. for Experimental Nephrology. Central Emek Hospital, Afula Israel
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Gonzalez LM, Moeser AJ, Blikslager AT. Animal models of ischemia-reperfusion-induced intestinal injury: progress and promise for translational research. Am J Physiol Gastrointest Liver Physiol 2015; 308:G63-75. [PMID: 25414098 PMCID: PMC4297854 DOI: 10.1152/ajpgi.00112.2013] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Research in the field of ischemia-reperfusion injury continues to be plagued by the inability to translate research findings to clinically useful therapies. This may in part relate to the complexity of disease processes that result in intestinal ischemia but may also result from inappropriate research model selection. Research animal models have been integral to the study of ischemia-reperfusion-induced intestinal injury. However, the clinical conditions that compromise intestinal blood flow in clinical patients ranges widely from primary intestinal disease to processes secondary to distant organ failure and generalized systemic disease. Thus models that closely resemble human pathology in clinical conditions as disparate as volvulus, shock, and necrotizing enterocolitis are likely to give the greatest opportunity to understand mechanisms of ischemia that may ultimately translate to patient care. Furthermore, conditions that result in varying levels of ischemia may be further complicated by the reperfusion of blood to tissues that, in some cases, further exacerbates injury. This review assesses animal models of ischemia-reperfusion injury as well as the knowledge that has been derived from each to aid selection of appropriate research models. In addition, a discussion of the future of intestinal ischemia-reperfusion research is provided to place some context on the areas likely to provide the greatest benefit from continued research of ischemia-reperfusion injury.
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Affiliation(s)
- Liara M. Gonzalez
- 1Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina; and
| | - Adam J. Moeser
- 2Department of Population Health and Pathobiology, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina
| | - Anthony T. Blikslager
- 1Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina; and
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Alexander JS, Ganta VC, Jordan PA, Witte MH. Gastrointestinal lymphatics in health and disease. ACTA ACUST UNITED AC 2011; 17:315-35. [PMID: 20022228 DOI: 10.1016/j.pathophys.2009.09.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 12/17/2022]
Abstract
Lymphatics perform essential transport and immune regulatory functions to maintain homeostasis in the gastrointestinal (GI) system. Although blood and lymphatic vessels function as parallel and integrated systems, our understanding of lymphatic structure, regulation and functioning lags far behind that of the blood vascular system. This chapter reviews lymphatic flow, differences in lymphangiogenic and hemangiogenic factors, lymphatic fate determinants and structural features, and examines how altered molecular signaling influences lymphatic function in organs of the GI system. Innate errors in lymphatic development frequently disturb GI functioning and physiology. Expansion of lymphatics, a prominent feature of GI inflammation, may also play an important role in tissue restitution following injury. Destruction or dysregulation of lymphatics, following injury, surgery or chronic inflammation also exacerbates GI disease activity. Understanding the physiological roles played by GI lymphatics is essential to elucidating their underlying contributions to forms of congenital and acquired forms of GI pathology, and will provide novel approaches for therapy.
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Affiliation(s)
- J S Alexander
- Louisiana State University Health Sciences Center-Shreveport, Molecular and Cellular Physiology, Shreveport, LA, United States
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7
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Granger DN, Kvietys PR, Korthuis RJ, Premen AJ. Microcirculation of the intestinal mucosa. Compr Physiol 2011. [DOI: 10.1002/cphy.cp060139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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9
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Kretsos K, Kasting GB. Dermal capillary clearance: physiology and modeling. Skin Pharmacol Physiol 2005; 18:55-74. [PMID: 15767767 DOI: 10.1159/000083706] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Accepted: 10/07/2004] [Indexed: 11/19/2022]
Abstract
Substances applied to the skin surface may permeate deeper tissue layers and pass into the body's systemic circulation by entering blood or lymphatic vessels in the dermis. The purpose of this review is an in-depth analysis of the dermal clearance/exchange process and its constituents: transport through the interstitium, permeability of the microvascular barrier and removal via the circulation. We adapt an 'engineering' viewpoint with emphasis on quantifying the dermal microcirculatory physiology, providing the theoretical framework for the physics of key transport processes and reviewing the available computational clearance models in a comparative manner. Selected experimental data which may serve as valuable input to modeling attempts are also reported.
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Affiliation(s)
- K Kretsos
- University at Buffalo, State University of New York, Department of Chemical and Biological Engineering, Buffalo, NY, USA.
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10
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Greitz D. On the active vascular absorption of plasma proteins from tissue: rethinking the role of the lymphatic system. Med Hypotheses 2002; 59:696-702. [PMID: 12445511 DOI: 10.1016/s0306-9877(02)00297-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
According to Starling's hypothesis, the osmotic pressure of plasma proteins in the capillary is the principal force for fluid absorption. The leakage of plasma proteins from capillaries to tissue during 24 h accounts for the total amount of plasma proteins in the vascular system. The same amount must therefore be reabsorbed by the lymphatic system, which is considered to be the sole absorber of proteins from tissue. However, it is a well-established routine in all kinds of organ transplantation to not restore the lymphatic system of the transplant. Experience has shown that this reconstruction is unnecessary, which consequently implies that the lymphatics are not of crucial importance for the survival of the organ. Inevitably, we must therefore question the vital role that the lymphatic system has been attributed in maintaining homeostasis as the sole absorber of proteins. Instead, it is proposed that the major part of plasma proteins in tissue is actively absorbed by the capillaries.
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Affiliation(s)
- Dan Greitz
- Department of Neuroradiology, MR-Research Center, Karolinska Hospital, Stockholm, Sweden.
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11
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Murphy TJ, Thurston G, Ezaki T, McDonald DM. Endothelial cell heterogeneity in venules of mouse airways induced by polarized inflammatory stimulus. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 155:93-103. [PMID: 10393842 PMCID: PMC1866655 DOI: 10.1016/s0002-9440(10)65104-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We sought to determine whether the changes in microvascular endothelial cells (EC) caused by a polarized chronic inflammatory stimulus depend on proximity to the stimulus. C3H mice were infected with Mycoplasma pulmonis, which attaches to the airway epithelium and creates a polarized inflammatory stimulus across the airway wall. At 1, 2, or 4 weeks, the tracheal vasculature was stained by perfusion of silver nitrate to mark EC borders or biotinylated Lycopersicon esculentum lectin to label the EC surface and adherent leukocytes. E-selectin immunoreactivity and EC proliferation were also localized. We found that the size, shape, and immunoreactivity for adhesion molecules on EC nearest the airway lumen (subepithelial EC) were different from those on the opposite surface of the same vessels. Subepithelial EC were smaller, more irregular in shape, had greater E-selectin immunoreactivity, and had twice as many adherent leukocytes. In contrast, proliferating EC were uniformly distributed around the vessel circumference. We conclude that the polarized stimulus created by M. pulmonis infection differentially changes the size, shape, and function of EC nearest the airway epithelium. This heterogeneity may result from a gradient of inflammatory mediators that triggers the influx of leukocytes into the airway lumen.
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Affiliation(s)
- T J Murphy
- Department of Anatomy and Cardiovascular Research Institute,* University of California, San Francisco, California, USA
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12
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Hemlin M. Fluid flow across the jejunal epithelia in vivo elicited by d-c current: effects of mesenteric nerve stimulation. ACTA PHYSIOLOGICA SCANDINAVICA 1995; 155:77-85. [PMID: 8553880 DOI: 10.1111/j.1748-1716.1995.tb09950.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The aim of this study was twofold: (1) to investigate the effect of electrical gradients on fluid transport across the rat jejunal mucosa in vivo; and (2) to evaluate the effect of mesenteric nerve stimulation (MNS) on current-induced fluid flow. Segments of rat jejunum were mounted with intact blood circulation in an in vivo chamber, allowing parallel registration of net fluid transport rate (NFT) and electrical properties of the tissue. Directed currents (d-c) of varying densities were passed across the jejunal wall in both directions and the current-induced fluid flows were measured. D-c current elicited fluid flows across the jejunal mucosa towards the cathode in both directions in a 'dose-dependent' manner. The effect was markedly greater when the anode was placed on the serosal side (s-->m current) than when it was placed on the mucosal side (m-s current). MNS abolished m-->s current induced flow whereas the effect of s-->m current was not significantly changed. It was concluded that: (1) true electro-osmosis probably accounts for the major portion of current-induced fluid flow in this model; (2) current induced fluid flow is rectified in opposite directions in vivo and in vitro; and (3) MNS inhibits current-induced fluid flow m-->s, possibly via a sympathetic effect on epithelial permeability.
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Affiliation(s)
- M Hemlin
- Department of Physiology, University of Göteborg, Sweden
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13
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MacPhee PJ, Michel CC. Fluid uptake from the renal medulla into the ascending vasa recta in anaesthetized rats. J Physiol 1995; 487:169-83. [PMID: 7473246 PMCID: PMC1156607 DOI: 10.1113/jphysiol.1995.sp020869] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
1. We have investigated fluid movements between superficial ascending vasa recta (AVR) and the interstitium of exposed papillae of the renal medullae in 15-day-old Sprague-Dawley rats anaesthetized with Hypnorm and Hypnovel. 2. Using a development of the red cell micro-occlusion technique, fluid filtration and reabsorption rates per unit area of vessel wall (Jv/A) were determined in 54 single perfused AVR at known microvascular pressures (Pc). The relation between Jv/A and Pc was non-linear suggesting hydraulic permeabilities (Lp) of 50-100 x 10(-7) cm s-1 cmH2O-1 when Pc was between 0-10 cmH2O and 150-200 x 10(-7) cm s-1 cmH2O-1 when Pc was 10-15 cmH2O. 3. Rates of fluid reabsorption into the AVR estimated by a densitometric technique in a further fourteen vessels were consistent with Lp values of 50-100 x 10(-7) cm s-1 cmH2O-1 when Pc was -2 to 0 cmH2O. 4. The effective oncotic pressures of perfusates containing bovine serum albumin (BSA) were consistent with minimum values for the reflection coefficients of the walls of the AVR to BSA of between 0.59 and 0.72. 5. The concentration of native serum albumin in the papillary interstitial fluid was 9.1 +/- 0.6 mg ml-1 (mean +/- S.E.M., n = 16, from 9 rats), which is approximately 25% of the plasma level. 6. After their microinjection into the medullary interstitium, Patent Blue V and Evans Blue-albumin cleared within 1 min. There was no evidence of preferential movement of either dye towards the base of the exposed renal medulla. 7. Because Lp of the AVR is high, mean pressures of only approximately 3 cmH2O are necessary to account for the total clearance of fluid from the medullary interstitium into the AVR. From published data and from our own observations, it appears that differences in hydrostatic and oncotic pressure across the walls of the AVR are more than sufficient to provide this driving force. The possibility of the clearance of protein from the interstitium into the AVR is discussed.
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Affiliation(s)
- P J MacPhee
- Department of Physiology & Biophysics, St Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, London, UK
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Clark AB, Sims MR, Leppard PI. An analysis of the effect of tooth intrusion on the microvascular bed and fenestrae in the apical periodontal ligament of the rat molar. Am J Orthod Dentofacial Orthop 1991; 99:21-9. [PMID: 1986518 DOI: 10.1016/s0889-5406(05)81676-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An analysis of the rat apical periodontal ligament (PDL) microvascular bed and fenestrae was conducted to evaluate the effect of a continuous 1.0 N intrusive tooth load for 30 minutes. The microvascular bed consisted of postcapillary-sized venules, venous and arterial capillaries, and terminal arterioles. Intrusion produced significant increases (p less than 0.01) in vascular volume for postcapillary-sized venules and venous capillaries in three of the four animals. Arterial capillaries, overall, showed a statistically significant increase (p less than 0.01). The endothelial surface area (micron2 x 10(6)) per cubic millimeter of PDL responded variably in postcapillary-sized venules and venous capillaries but showed a strong trend to increase in arterial capillaries. After tooth intrusion a significant reduction (p less than 0.01) occurred in the number of fenestrae per square micrometer of endothelium in postcapillary-sized venules and venous capillaries. Fenestrae in the control PDL had a mean diameter of 51.5 nm +/- 0.6 (SE), whereas those on the intrusion side were smaller (p less than 0.05), measuring 49.9 nm +/- 0.4 (SE).
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Affiliation(s)
- A B Clark
- Department of Dentistry, University of Adelaide, Australia
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Smolich JJ, Shimada T, Canale E, Campbell GR. Developmental morphology of vascular and lymphatic capillaries in the working myocardium and Purkinje bundle of the sheep septomarginal band. Anat Rec (Hoboken) 1990; 226:48-56. [PMID: 2297083 DOI: 10.1002/ar.1092260107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The normal development of vascular and lymphatic capillaries in the right ventricular septomarginal band of the sheep heart was studied in 9 fetuses aged 60-143 days (term = 147 days), 14 lambs aged 1 day to 16 weeks, and 3 adults. Tissue was fixed by perfusion and examined with light and transmission electron microscopy. The septomarginal band is composed of working myocardium and a well-defined peripheral bundle of Purkinje cells. Vascular capillaries of the working myocardium were closely apposed to myocardial cells. By contrast, vascular capillaries of the Purkinje bundle were situated within the connective tissue sheath and septa, at variable distances from the Purkinje cells. After birth, the capillaries of the Purkinje bundle were also found in grooves and tunnels within the Purkinje strands. The ultrastructure of fetal vascular capillaries associated with myocardial and Purkinje cells was initially similar, and characterized by an abundance of synthetic organelles in endothelial cells and pericytes. However, after 115 days in utero, capillary endothelium with diaphragmed fenestrae, 40-60 nm in width, were observed within the Purkinje bundle. The fenestrae attained an average frequency of 1 per 11 capillary cross sections just before term, and this was maintained in lambs and adults. The ultrastructure of lymphatic capillaries, which were not observed in the septomarginal band until just before term, changed little during development.
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Affiliation(s)
- J J Smolich
- Department of Anatomy, University of Melbourne, Parkville, Australia
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16
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Gannon BJ, Perry MA. Histoanatomy and ultrastructure of vasculature of alimentary tract. Compr Physiol 1989. [DOI: 10.1002/cphy.cp060136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lew K, Sims MR, Leppard PI. Tooth extrusion effects on microvessel volumes, endothelial areas, and fenestrae in molar apical periodontal ligament. Am J Orthod Dentofacial Orthop 1989; 96:221-31. [PMID: 2773868 DOI: 10.1016/0889-5406(89)90459-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Extrusive tooth loads, simulating short-term orthodontic movements, have not previously been used for transmission electron microscopic quantification of their effects on the periodontal ligament vessels. In this study, a continuous extrusive load of 1.0 N, applied to the rat maxillary first molar for 30 minutes, produced statistically significant changes in the microvascular bed of the tensioned apical periodontal ligament. The mean vascular volume, as a percentage of apical periodontal ligament volume, increased (p less than 0.01) in postcapillary-sized venules, venous capillaries, arterial capillaries, and terminal arterioles from 16.6% to 22.3%, 2.0% to 2.7%, 0.4% to 1.0%, and 1.0% to 2.5%, respectively. Mean endothelial surface area per cubic millimeter of apical periodontal ligament tissue increased (p less than 0.01) in postcapillary-sized venules from 16.8 to 25.7 x 10(6) microns 2/mm3, in venous capillaries from 3.0 to 4.8 x 10(6) microns 2/mm3, and in arterial capillaries from 0.7 to 1.5 x 10(6) microns 2/mm3. The number of fenestrae per square micron of endothelium in postcapillary-sized venules, venous capillaries, and arterial capillaries showed a mean increase from 0.02 to 0.07, 0.11 to 0.31, and 0.02 to 0.21 fenestrae/microns 2, respectively (p less than 0.01). Fenestrae per cubic millimeter of periodontal ligament tissue also demonstrated a statistically significant increase with extrusion (p less than 0.01) in postcapillary-sized venules from 0.37 to 1.55 x 10(6) fenestrae/mm3, in venous capillaries from 0.27 to 1.34 x 10(6) fenestrae/mm3, and in arterial capillaries from 0.02 to 0.22 x 10(6) fenestrae/mm3. Fenestrae in control vessels had a mean diameter of 54.2 +/- 0.56 nm (SE) compared with 61.1 +/- 0.7 nm in tensioned vessels (p less than 0.01). This investigation demonstrates multiple ultrastructural changes in the periodontal ligament microvascular bed after tooth extrusion.
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Affiliation(s)
- K Lew
- National University of Singapore, Faculty of Dentistry
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Korte GE, Burns MS, Bellhorn RW. Epithelium-capillary interactions in the eye: the retinal pigment epithelium and the choriocapillaris. INTERNATIONAL REVIEW OF CYTOLOGY 1989; 114:221-48. [PMID: 2661458 DOI: 10.1016/s0074-7696(08)60862-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- G E Korte
- Department of Ophthalmology, Montefiore Medical Center, Bronx, New York 10467
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Grevers G, Herrmann U. Fenestrated endothelia in vessels of the nasal mucosa. An electron-microscopic study in the rabbit. ARCHIVES OF OTO-RHINO-LARYNGOLOGY 1987; 244:55-60. [PMID: 3619756 DOI: 10.1007/bf00453492] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The ultrastructure of the vessels in the normal respiratory and olfactory mucosa of the nasal septum was studied in 15 adult rabbits. Capillaries with continuous and fenestrated endothelia could be observed in both tissues. In the respiratory part, many of the fenestrated capillaries were located subepithelially with their fenestrations facing the adjacent epithelium. Fenestrated capillaries of the olfactory mucosa were found mainly in the deeper parts of the tunica propria and usually revealed only a small number of fenestrations in their endothelial lining. It was also demonstrated that muscularized veins sometimes displayed fenestrated areas in their attenuated endothelia. These results are discussed and compared with the appropriate literature. Our results confirm that there is a link between the morphological peculiarities of the vascular wall and the functional behaviour of the nasal mucosa. These findings also emphasize that endothelial fenestrations seem to be characteristic for a certain segment of the microcirculatory system rather than for a distinct type of capillary vessel.
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Abstract
In this analysis of published data we evaluate the permeabilities of unit area of fenestral pathway to water and small solutes. These properties are then used to assess the functional significance of the fenestral diaphragm which, along with the glycocalyx and basement membrane, makes up the fenestral pathway. Endothelial hydraulic conductance and permeability to small lipophobic solutes increase with fenestral density in a variety of mammalian tissue. The increase in conductance per unit increment in fenestral area (Kfen) averages 0.38 micron X s-1 X mm Hg-1 (regression analysis). This value means that a single fenestra (diam 0.06 micron, area 0.003 micron2) has a greater conductance than 1 micron2 of continuous (skeletal muscle) endothelium. Similarly the diffusional permeability of unit fenestral area (Pfen) to B12 and inulin is high. But neither Kfen nor Pfen is as great as might be expected from the extreme thinness of the diaphragm (less than or equal to 5 nm). Pfen depends on diffusivity (D) and pathlength (delta chi): Pfen = D'/delta chi. D' depends on the fraction of the fenestral surface available for exchange and on restriction to diffusion. These relations were applied to test the view that the diaphragm, rather than the glycocalyx or basement membrane, is the major barrier to fluid and small solutes in the fenestral pathway. If this were turn, over 98 1/2% of the diaphragm's area would have to be totally impermeable in order to yield the observed values of Pfen--a result consequent upon the extreme thinness of the diaphragm. In this event there would be less than one equivalent pore (radius 5-11 nm) per diaphragm on average-which is incompatible with ultrastructural evidence. The resistance of a 5-nm-thick diaphragm containing one or more pores is not high enough to account for fenestral resistance. It is concluded that much thicker structures, such as the glycocalyx and/or basement membrane, and not the diaphragm, account for fenestral resistance to small-solute and water transport.
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Anatomic and Physiologic Aspects of Peritoneal Dialysis. Nephrology (Carlton) 1984. [DOI: 10.1007/978-1-4612-5284-9_137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Nolph KD, Miller FN, Pyle WK, Popovich RP, Sorkin MI. An hypothesis to explain the ultrafiltration characteristics of peritoneal dialysis. Kidney Int 1981; 20:543-8. [PMID: 7343705 DOI: 10.1038/ki.1981.175] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We present an hypothesis that could account for many characteristics of ultrafiltration and solute movement during peritoneal dialysis. The hypothesis describes transcapillary ultrafiltration and can account for (1) the osmotic effectiveness of rapidly absorbed glucose, (2) small solute sieving in a system permitting protein loss, (3) functional estimates of effective pore sizes as low as 11 A for urea and as high as 62 A for proteins from hydrodynamic analyses, (4) isolated loss of ultrafiltration without loss of clearance, (5) decreased ultrafiltration with decreased clearances, and (6) increased ultrafiltration with decreased clearances. Mechanisms for fluid movement from the peritoneal interstitium into the peritoneal cavity may involve both hydrostatic and osmotic pressure. Interstitial water pathway dimensions, interstitial gel surface charges, mesothelial cell surface charges, and transmesothelial-cell water movement might also account for sieving effects during peritoneal ultrafiltration.
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Giraud GD, MacCannell KL. Measurement of mucosal blood flow by assay of absorption of 125I from the intestinal lumen. JOURNAL OF PHARMACOLOGICAL METHODS 1981; 6:65-75. [PMID: 7265995 DOI: 10.1016/0160-5402(81)90085-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A method which utilized the absorption of 125I as a measure of intestinal mucosal blood flow was developed. In the pentobarbital anesthetized dog a segment of mid-jejunum was isolated from adjacent vasculature and perfused with 125I solution. Superior mesenteric artery flow, blood flow to the isolated segment of intestine and 125I absorption were measured. Changes in 125I absorption were found to correlated closely with changes in blood flow (r = 0.95). Using an autoradiographic technique 125I absorption was found to be localized to the intestinal mucosa.
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Higgins JC, Eady RA. Human dermal microvasculature: I. Its segmental differentiation. Light and electron microscopic study. Br J Dermatol 1981; 104:117-29. [PMID: 7213547 DOI: 10.1111/j.1365-2133.1981.tb00033.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Light microscopic examination of I micrometer thick epoxy resin sections of human skin preserved in fixative normally used for electron microscopy allows division of the microvasculature of the reticular and superficial dermis into several distinct segments. More precise delineation of these components can be achieved by correlative study using electron microscopy. Measurement of vessel diameter in tissue sections is of limited value in vessel classification because there is a wide overlap between different vascular segments and the results are influenced by the type of fixative used for processing the tissue. Detailed observation of the morphological characteristics of the endothelium and its investment, including the elastic and basal laminae, is consider preferable for identifying individual vascular segments. Differences in body region do not appear to have any obvious influence on vessel structure although there are regional differences in vessel density and arrangement. In comparison with earlier studies on animal tissues or human skin, no structures resembling arteriovenous shunts or precapillary sphincters were observed in the present investigation. However, closed fenestrae and other structures thought to be transendothelial channels were often found at the tips of capillary loops adjacent to the epidermis.
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Johansson BR. Size and distribution of endothelial plasmalemmal vesicles in consecutive segments of the microvasculature in cat skeletal muscle. Microvasc Res 1979; 17:107-17. [PMID: 449718 DOI: 10.1016/0026-2862(79)90400-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Ogston AG, Michel CC. General descriptions of passive transport of neutral solute and solvent through membranes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1979; 34:197-217. [PMID: 375302 DOI: 10.1016/0079-6107(79)90018-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Mitnick H, Hoffstein S, Weissmann G. Fate of antigen after intravenous and intraarticular injection into rabbits. ARTHRITIS AND RHEUMATISM 1978; 21:918-29. [PMID: 737015 DOI: 10.1002/art.1780210808] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
To determine the manner in which small protein antigens enter the synovium and are localized, horseradish peroxidase (molecular weight 40,000) was injected by intravenous and intraarticular routes. Passage of antigen from capillary lumen to joint space and vice versa occurred primarily across fenestrated vessels. Antigen localized to collagen fibers and lining cells. At low concentrations of antigen, antigen was taken up predominantly by marcophages, whereas at higher concentrations both macrophages and fibroblast-like lining cells accumulated antigen.
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Winne D. Blood flow in intestinal absorption models. JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS 1978; 6:55-78. [PMID: 650422 DOI: 10.1007/bf01066063] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Braverman IM, Yen A. Ultrastructure of the human dermal microcirculation. II. The capillary loops of the dermal papillae. J Invest Dermatol 1977; 68:44-52. [PMID: 830769 DOI: 10.1111/1523-1747.ep12485165] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Electron microscopy was used to define the ultrastructure of the capillary loops in the dermal papillae of normal, eczematous, and psoriatic skin. Capillary loops were reconstructed from 1-mum plastic-embedded sections. Ultrathin sections were taken at 4- to 6-mum intervals for correlation with the thick sections. The capillary loops of normal forearm and elbow skin could be divided into two segments: an intrapapillary and extrapapillary portion. The intrapapillary portion had the ultrastructural characteristics of an arterial capillary--homogeneous-appearing basement membrane without bridged fenestrations. The ascending limb in the extrapapillary portion was also an arterial capillary and the descending limb in the same portion had venous characteristics--multilayered basement membrane. The intrapapillary arterial loop developed venous characteristics abruptly after the vessel left the dermal papilla proper. The capillary loops in acute nummular eczema were identical in ultrastructure to those of normal skin. Bridged fenestrations were found in one capillary loop in eczema but not in normal skin. By contrast, the intrapapillary capillary loops in psoriasis were venous capillaries which were characterized by bridge fenestrations and multilayered basement membrane. The ultrastructural features of the capillary loops and those of the microcirculatory segments in the horizontal dermal plexus should provide sufficient criteria for one to evaluate the nature of vascular abnormalities that occur in the upper dermis.
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Casley-Smith JR, Sims MA. Protein concentrations in regions with fenestrated and continuous blood capillaries and in initial and collecting lymphatics. Microvasc Res 1976; 12:245-57. [PMID: 1004238 DOI: 10.1016/0026-2862(76)90024-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Yen A, Braverman IM. Ultrastructure of the human dermal microcirculation: the horizontal plexus of the papillary dermis. J Invest Dermatol 1976; 66:131-42. [PMID: 1249441 DOI: 10.1111/1523-1747.ep12481678] [Citation(s) in RCA: 106] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Electron microscopy was used to define the ultrastructure of the various segments of the human cutaneous microcirculation in normal forearem skin. The organization of the vessels in the horizontal plexus of the papillary dermis was reconstructed from 1-mum plasticembedded sections. Ultrathin sections were taken at 10- to 20-mum intervals over a distance of 450 mum. Arterioles were followed through the capillary bed to their venous connections. Terminal arterioles, arterial and venous capillaries, and postcapillary venules were identified on the basis of size, cellular composition of their walls, and their relationship to the other segments of the microvascular bed. The arterial segments were characterized by a homogeneous basement membrane and the venous segments by a multilaminated basement membrane. The elastic lamina in the arterioles was a discontinuous layer which gradually disappeared from the arteriolar wall to form an external sheath just before the arteriole connected with the arterial capillary segment. The vascular walls varied from 1 to 5 mum in all of the segments of the microvascular bed. Criteria are proposed for identifying the various segments of the microcirculation so that their roles in dermatoses and vascular malformations can be evaluated.
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Casley-Smith JR. The functioning and interrelationships of blood capillaries and lymphatics. EXPERIENTIA 1976; 32:1-12. [PMID: 765142 DOI: 10.1007/bf01932595] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The structure and function of blood capillaries, as related to permeability, depends on tight, close and (in injured vessels) open junctional regions, small vesicles, vacuoles (in injured vessels) and fenestrae. The basement membrane presents a hindrance to the larger macromolecules, at high flow rates, but not to small molecules. The connective tissue channels are probably the paths by which macromolecules, and most of the small ones, pass from the arterial-limbs to the venous ones, and to the lymphatics. In some regions these channels are grouped in special systems: the prelymphatics. The initial lymphatics take up material via open junctions, which close during tissue-compression. The collecting lymphatics retain the lymph because they do not have open junctions. In the close junctional regions the motive force for water flow is the result of Starling's forces; diffusion is very important for other small molecules. The small vesicles transport macromolecules slowly by Brownian motion, as may the vacuoles, but possibly these latter are moved actively. There is much evidence that colloids can develop high effective osmotic pressures even across pores much larger than their molecules, and that proteins can be dragged up a concentration gradient by the resultant fluid flow. On the basis of this, hypotheses have been developed about the functioning of venous-limb fenestrae and the initial lymphatics, for which there is much theoretical, in vitro, and in vivo evidence. Thus, in fenestrated regions there is held to be a large local circulation through the tissues, of which a quantitatively small, but qualitatively vital, part goes to the lymphatics. Material is considered usually to enter these latter because of the relative concentration of the lymph. It is becoming increasingly evident that in the study of the microvasculature, as with other systems, there is much to be gained by quantifying fine structural observations and by combining and contrasting this data, via physical laws, with that obtained by other methods where the characteristics of whole organs and regions are studied. Thus one can obtain interrelated information, which is not possible by either method alone, and which gives us a vital, comprehensive, perspective of the ways in which whole systems function, and how different systems interact. In this paper I shall show how this approach has yielded much that is new about the functioning of different kinds of blood capillaries, of the tissue channels, of the whole lymphatic system, and of the ways they affect each other.
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Casley-Smith JR, Green HS, Harris JL, Wadey PJ. The quantitative morphology of skeletal muscle capillaries in relation to permeability. Microvasc Res 1975; 10:43-64. [PMID: 1143097 DOI: 10.1016/0026-2862(75)90019-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Casley-Smith JR, O'Donoghue PJ, Crocker KW. The quantitative relationships between fenestrae in jejunal capillaries and connective tissue channels: proof of "tunnel-capillaries". Microvasc Res 1975; 9:78-100. [PMID: 1117860 DOI: 10.1016/0026-2862(75)90053-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Casley-Smith JR. A theoretical support for the transport of macromolecules by osmotic flow across a leaky membrane against a concentration gradient. Microvasc Res 1975; 9:43-8. [PMID: 1117857 DOI: 10.1016/0026-2862(75)90050-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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37
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Michel CC. The transport of solute by osmotic flow with particular reference to the transport of protein across the venous fenestrae of visceral capillaries. Microvasc Res 1974; 8:122-4. [PMID: 4416546 DOI: 10.1016/0026-2862(74)90070-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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38
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Leonard JI, Abbrecht PH. Dynamics of plasma-interstitial fluid distribution following intravenous infusions in dogs. An experimental and computer simulation study. Circ Res 1973; 33:735-48. [PMID: 4586838 DOI: 10.1161/01.res.33.6.735] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The dynamic distribution of intravenously infused solutions between the plasma and the interstitial compartments was studied. A mathematical model developed to simulate infusion experiments considered transcapillary fluid and protein exchange, lymph flow, interstitial compliance, capillary surface area, and peripheral vascular resistance. The experimental arterial and venous blood pressure responses and the infusion rate were used as forcing functions. A piecewise optimization procedure resulted in excellent agreement between the simulated and experimental plasma volume responses and provided reasonable time-varying behavior for the precapillary-postcapillary resistance ratio and the capillary surface area. The model was tested with experimental data collected by infusing isotonic Tyrode's or dextran solution into nephrectomized dogs. Blood volume was measured continuously by giving a single injection of
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Cr-labeled red cells and monitoring the blood radioactivity as it passed through an extracorporeal shunt. The model predicted qualitatively different responses for the precapillary-postcapillary resistance ratio depending on the type of solution infused and the value assumed for tissue compliance. Further analysis indicated that the assumption of a tissue space with overall high compliance (approximately 100 ml/kg mm Hg
-1
) is more realistic than are the much lower compliances previously reported. Parametric studies revealed that the capillary surface area, the precapillary-postcapillary resistance ratio, and the tissue compliance, but not the lymph flow or the transcapillary protein movement, exert a strong influence on the short-term plasma retention of infused fluids.
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Mohamed AH, Waterhouse JP, Friederici HH. The fine structure of gingival terminal vascular bed. Microvasc Res 1973; 6:137-52. [PMID: 4748016 DOI: 10.1016/0026-2862(73)90016-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Casley-Smith JR, Bolton T. The presence of large effective colloidal osmotic pressures across large pores. Microvasc Res 1973; 5:213-6. [PMID: 4694285 DOI: 10.1016/0026-2862(73)90072-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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41
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Casley-Smith JR. A method for quantifying electron staining, obtaining the dry specific gravity of specimens in sections, and measuring section thickness. J Microsc 1972. [DOI: 10.1111/j.1365-2818.1972.tb01065.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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