Quantitative morphometry of conjunctival microcirculation in diabetes mellitus

Fenton, Bruce M.; Zweifach, Benjamin W.; Worthen, David M.

doi:10.1016/0026-2862(79)90025-6

Cited by 31 publications

(13 citation statements)

References 7 publications

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“…Use has been made of nailfold capillaroscopy in the diagnosis and treatment of peripheral vascular diseases, diabetes and hematological disorders 1-3 . Problems with movement have restricted the use of the bulbar conjunctiva for clinical applications in opthalmology [4][5][6] . Other locations observed by intravital microscopy include the microcirculation of the skin, lip, gingival tissue and tongue 4 .…”

Section: New Technologymentioning

confidence: 99%

Orthogonal polarization spectral imaging: A new method for study of the microcirculation

Groner¹,

Winkelman

Harris³

et al. 1999

Nat Med

712

435

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Fig. 1 a, Orthogonal polarization spectral imaging probe. b, Optical schematic of the OPS imaging probe. A typical magnification of ×10 is maintained between the target and its image. This results in a resolution of approximately 1 µm/pixel, which is limited by the dimension of the CCD pixel. The probe can be focused from the target surface to 1.0-mm depth, depending on the type of target and the optics used. In vivo, the typical depth of focus is approximately 0.2 mm. c, Optical density of a graduated gray scale (catalog number 152-7662; Kodak) was measured in the presence of the polarization analyzer (b) or with a 0.5 OD neutral density filter (ć) used in place of the analyzer. Average light intensity for each gray level was converted to OD by the following formula: OD = log 10 ((I m -I d )/(I max -I d )) where I m = measured light intensity, I d = dark light intensity (obtained using a black velvet target), I max = intensity of white target. NEW TECHNOLOGYDifferent disease states, including diabetes, hypertension and coronary heart disease, produce distinctive microvascular pathologies. So far, imaging of the human microcirculation has been limited to vascular beds in which the vessels are visible and close to the surface (for example, nailfold, conjunctiva). We report here on orthogonal polarization spectral (OPS) imaging, a new method for imaging the microcirculation using reflected light that allows imaging of the microcirculation noninvasively through mucus membranes and on the surface of solid organs. In OPS imaging, the tissue is illuminated with linearly polarized light and imaged through a polarizer oriented orthogonal to the plane of the illuminating light. Only depolarized photons scattered in the tissue contribute to the image. The optical response of OPS imaging is linear and can be used for reflection spectrophotometry over the wide range of optical density typically achieved by transmission spectrophotometry. A comparison of fluorescence intravital microscopy with OPS imaging in the hamster demonstrated equivalence in measured physiological parameters under control conditions and after ischemic injury. OPS imaging produced high-contrast microvascular images in people from sublingual sites and the brain surface that appear as in transillumination. The technology can be implemented in a small optical probe, providing a convenient method for intravital microscopy on otherwise inaccessible sites and organs in the awake subject or during surgery for research and for clinical diagnostic applications.At present, the use of microvascular imaging in diagnosis and treatment of human disease is limited. Use has been made of nailfold capillaroscopy in the diagnosis and treatment of peripheral vascular diseases, diabetes and hematological disorders 1-3 . Problems with movement have restricted the use of the bulbar conjunctiva for clinical applications in opthalmology 4-6 . Other locations observed by intravital microscopy include the microcirculation of the skin, lip, gingival tissue and tongue 4 . Laser-sca...

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Section: New Technologymentioning

confidence: 99%

Orthogonal polarization spectral imaging: A new method for study of the microcirculation

Groner¹,

Winkelman

Harris³

et al. 1999

Nat Med

712

435

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“…The resulting simulations were essentially linear algebra solutions. 27,28 When quantitative models of FahraeusLindqvist effect and plasma skimming were published, they were incorporated into the simulations. Two basic approaches have been followed.…”

Section: B Modeling Of Microvascular Network Flowmentioning

confidence: 99%

Blood flow in microvascular networks: A study in nonlinear biology

Geddes

Carr

et al. 2010

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Plasma skimming and the Fahraeus-Lindqvist effect are well-known phenomena in blood rheology. By combining these peculiarities of blood flow in the microcirculation with simple topological models of microvascular networks, we have uncovered interesting nonlinear behavior regarding blood flow in networks. Nonlinearity manifests itself in the existence of multiple steady states. This is due to the nonlinear dependence of viscosity on blood cell concentration. Nonlinearity also appears in the form of spontaneous oscillations in limit cycles. These limit cycles arise from the fact that the physics of blood flow can be modeled in terms of state dependent delay equations with multiple interacting delay times. In this paper we extend our previous work on blood flow in a simple two node network and begin to explore how topological complexity influences the dynamics of network blood flow. In addition we present initial evidence that the nonlinear phenomena predicted by our model are observed experimentally. © 2010 American Institute of Physics. ͓doi:10.1063/1.3530122͔Nonlinear phenomena are very common in nature. Here we explore one example from biology, the flow of blood in small blood vessel networks. Nonlinearity is revealed in this case by the existence of multiple steady state solutions and by the evolution of spontaneous fluctuations in network flow. These nonlinear phenomena are not dependent on any biological control mechanisms but are solely due to the interaction of well-known blood rheological properties and network geometry. We examine these interactions through analysis and numerical computation. We also present our first in vitro experimental data on spontaneous oscillations in blood flow in this paper.

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“…Os linfáticos fazem parte da unidade microcirculatória e sua função é importante na retirada de macromoléculas do interstício. -tortuosidade do ramo ou segmento eferente (14-18) -ramificações do capilar (19) -hemorragias (19,20) Há consenso, nos achados, de freqüência aumentada de edema, microaneurismas, dilatação de segmento transverso e tortuosidade do ramo eferente, em diabéticos em relação a indivíduos normais, pela maioria dos autores (figuras 3 a 6) (14)(15)(16)(17)(18)(19)(20). O edema tem sido reconhecido pela presença de retificação de papila dér-mica, visibilidade difícil e presença de névoa translúcida que apaga parcialmente o capilar (figuras 4 a 6), podendo levar a um aspecto de encurtamento -a imagem de "ponto e vírgula" ou de "banca de peixe" (figura 6).…”

Section: Anatomia E Fisiologia Da Microcirculaçãounclassified

“…Diagnosticaram, em 20%, hemorragias, também observadas por Fenton e cols., em grupo semelhante de pacientes. Estes achados, no entanto, não foram confirmados pela maioria dos autores (19)(20).…”

Section: Anatomia E Fisiologia Da Microcirculaçãounclassified

Estudos morfológicos e funcionais da microcirculação da pele no diabetes mellitus

Halfoun

Fernandes

Pires

et al. 2003

Arq Bras Endocrinol Metab

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RESUMOOs autores analisam os principais métodos de investigação morfofuncional da microcirculação da pele em diabéticos, tanto na literatura médica recente quanto na própria experiência em videocapilaroscopia subungueal, no âmbito dos atuais avanços do conhecimento sobre a fisiopatologia da microangiopatia diabética. Na videocapilaroscopia basal, feita na região periungueal das mãos, ressaltam a importância e a significativa prevalência das alterações morfológicas como edema, microaneurismas, tortuosidade e dilatação do segmento venoso capilar, tanto em indivíduos diabéticos quanto em parentes de 1º grau com testes de tolerância à glicose normais. Mostram o valor dos estudos das respostas dinâmicas da microcirculação à isquemia e a estí-mulos farmacológicos, observadas, sobretudo, por medidas de velocidade e/ou fluxo sangüíneo na videocapilaroscopia e dopplerfluxometria a laser, que, na maioria dos trabalhos, estavam alteradas em fases muito precoces da doença, por vasodilatação inadequada. São descritas as medidas do diâmetro e da área do segmento transverso capilar em videocapilaroscopia que podem ser úteis como parâmetros-respostas ao teste de isquemia reperfusão. Os autores discutem as bases da fisiopatologia que justificam as alterações observadas na videocapilaroscopia tanto basal como dinâmica.

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Quantitative morphometry of conjunctival microcirculation in diabetes mellitus

Cited by 31 publications

References 7 publications

Orthogonal polarization spectral imaging: A new method for study of the microcirculation

Orthogonal polarization spectral imaging: A new method for study of the microcirculation

Blood flow in microvascular networks: A study in nonlinear biology

Estudos morfológicos e funcionais da microcirculação da pele no diabetes mellitus

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