The potential role of intestinal microcirculation for the development of inflammatory bowel diseases (IBD) has not been systematically investigated, mainly because of methodological problems. Using a well-established rodent model of IBD and intravital microscopy, the present study investigated whether (and when) gut microcirculation is disturbed in IBD, and whether microcirculatory ...

OBJECTIVE: Islet cell antibody (ICA) measurements in serum are used for large-scale screening to identify subjects who are at high risk of developing type 1 diabetes. The aim of this study was to adapt measurements to capillary whole blood samples to facilitate and reduce screening costs. RESEARCH DESIGN AND METHODS: ...

Capillaries consisting of two segments each packed with a different stationary phase were introduced for the control and manipulation of the electroosmotic flow (EOF) in capillary electrochromatography (CEC). This kind of column configuration was called segmented capillary where one segment was packed with octadecyl silica (ODS) and served as the ...

OBJECTIVE: This single-center, prospective, randomized, double-blind phase IV study in parallel-group design was carried out to investigate whether either of two different x-ray contrast media (iomeprol 350 or iopentol 350) injected into the axillary artery has any influence on cutaneous microcirculation. METHODS AND RESULTS: The investigation was carried out on ...

Sequential computed tomographic scanning was performed in patients with neck tumors after contrast material administration. For data analysis, a pharmacokinetic two-compartment model was employed that takes into account both capillary blood supply and bidirectional diffusion of the contrast agent across the capillary wall. This approach offers the possibility to quantitatively ...

We test three hypotheses arising from a model of oxygen delivery to brain tissue. The hypotheses claim that mitochondrial oxygen is negligible in brain tissue such that oxygen consumption depends solely on the mean capillary oxygen tension for a given capillary density; that capillary density is adjusted to satisfy the ...

This study was designed to evaluate the effects of crush injuries to the feeding arteries of a muscle flap on microcirculatory haemodynamics. Eighteen male Sprague-Dawley rats were divided into three experimental groups for intravital microscopy of the cremaster muscle flap. Group 1 served as control. In group 2 the common ...

The mechanisms behind oxygen mediated changes in tissue blood flow remain unsettled. Today these are thought to (from experiments on separate vessels and other tissues than the brain) operate through the vessels themselves, probably by involvement of the endothelium in the distal parts of the vascular tree. The aim of ...

Cortical blood flow at the level of individual capillaries and the coupling of neuronal activity to flow in capillaries are fundamental aspects of homeostasis in the normal and the diseased brain. To probe the dynamics of blood flow at this level, we used two-photon laser scanning microscopy to image the ...

The rat incisor is a commonly used model in studies of tooth eruption, amelogenesis and effects of mechanical loading on the dental and periodontal tissues. The purpose of this study was to assess the three-dimensional architecture of the microvascular bed of the rat incisor enamel organ, to describe the direction ...

A new and sensitive method for measurement of o-, m- and p-xylenes in human whole blood by capillary gas chromatography (GC) with cryogenic trapping is presented. After heating 0.5 ml of whole blood and 0.5 ml of distilled water containing the xylenes and aniline (internal standard, I.S.) in a 4.0-ml ...

A 26-year-old woman presented with a 2-month history of intermittent dim vision in her right eye and a diagnosis of central retinal vein occlusion (CRVO) was made. Investigations revealed Raynaud's phenomenon and cryofibrinogenemia. Skin capillaroscopy revealed tortuous vessels and decreased capillary blood-cell velocity in the capillaries of her finger nail ...

The luminal surface of the pecten oculi of the black kite (Milvus migrans), a diurnally active bird of prey, was examined by scanning electron microscopy. In this species the blood vessels are generally of two types, the small-calibre capillaries and the large-calibre afferent and efferent vessels. The luminal surface of ...

1. We have investigated the effects of varying flow velocity upon permeability to potassium ions (PK) of single perfused mesenteric microvessels in pithed frogs. 2. PK was estimated using a development of the single bolus microperfusion technique at chosen flow velocities (U) in the range of 150-7000 micron s-1. 3. ...

Any surgical procedure is followed by an inflammatory reaction, associated with arteriolar dilatation and increased capillary permeability. The normal evolution is in most cases a progressive decrease of the inflammatory signs. Some patients however, particularly after orthopedic trauma affecting the extremities, develop algodystrophy, initially characterized by arterial vasodilatation and low ...

Distributed models of blood-tissue exchange are widely used to measure kinetic events of various solutes from multiple tracer dilution experiments. Their use requires, however, a careful description of blood flow heterogeneity along the capillary bed. Since they have mostly been applied in animal studies, direct measurement of the heterogeneity distribution ...

A better understanding of transcapillary transport for tracer metaiodobenzylguanidine (MIBG) is desirable for development of tracer kinetic models that yield meaningful estimates of neuronal uptake function from tissue radioactivity time courses. This study utilized a multiple-indicator approach in Langendorff-perfused rat hearts to define transport mechanisms and determine the capillary permeability-surface ...

There is increasing evidence that endothelial damage occurs at a very early stage during the course of systemic scleroderma. Endothelial damage is accompanied by impaired microvascular function, which has clearly failed in patients with systemic scleroderma, as evidenced by necrosis of the fingertips in severe cases. We investigated two important ...

BACKGROUND: Arterial hypertension is known to be an important risk factor for cerebral and cardiovascular disease. Previous studies have demonstrated a decrease of capillary density in the perifoveal network in tandem with decreased capillary flow velocity in patients with essential hypertension. In a prospective study we quantified the retinal microcirculation ...

OBJECTIVES: This study was aimed to assess the peripheral circulatory functions of forestry workers exposed to hand-arm vibration, using simultaneous measurements of finger skin temperature (FST) and finger blood flow (FBF). METHODS: The subjects were five men with vibration-induced white finger (VWF), four subjects with numbness in their hands and ...

PURPOSE: The authors investigate cutaneous capillary blood flow using the cold pressor test and plasma endothelin-1 (ET-1) concentration in primary open-angle glaucoma (POAG) and capsular glaucoma (CG), and evaluate the connection between the two factors, which reflect vasoconstrictive mechanisms with a potential role in the pathogenesis of glaucoma. METHODS: The ...

We investigated, using a direct, intravital microscopic technique, whether nitric oxide (NO) from neuronal nitric oxide synthase (nNOS) plays a role in the cerebral capillary flow response to acute hypoxia. Erythrocyte flow in subsurface capillaries of the frontoparietal cortex of adult Sprague-Dawley rats was visualized using epifluorescence videomicroscopy after fluorescent ...

Using in vivo microscopy, red blood cell (RBC) velocities, functional capillary density (FCD), and overall changes in capillary blood flow (PI) were estimated following intraductal infusion of sodium taurocholate (0.8 ml; 4%) alone or in combination with systemic administration of somstostatin (single bolus SMS 100 microg/100 g body wt). Sodium ...

There is little information on the distribution of acinar perfusion because it is difficult to resolve blood flow within such small regions. We hypothesized that the known heterogeneity of arteriolar blood flow and capillary blood flow would result in heterogeneous acinar perfusion. To test this hypothesis, the passage of fluorescent ...

The vasculature of lumbar posterior root ganglia was investigated in human fetuses aged 17-24 weeks; using the corrosion casting technique and scanning electron microscopy. The arterial supply consisted of one main artery and occasional arterioles entering the ganglion at its pole and running axially, while the venous drainage was located ...

The dependence of uraemic solute clearance on the hydraulic and diffusive permeability index of an AN-69 capillary haemofilter is investigated during the treatment of patients with continuous arterio-venous haemodiafiltration (CAVHD). A mathematical model is presented to calculate solute clearance and the hydraulic and diffusive permeability index parameters from clinical data ...

Physiological angiogenesis occurs in female reproductive organs, in growing antlers as a result of long-term exposure to cold and possibly hypoxia, and due to increased activity (training) in skeletal and cardiac muscle. The common denominator is increased blood flow, which may result in increased velocity of flow and/or diameters in ...

The regulation of cochlear lateral wall blood flow was investigated in rats using histochemistry, immunohistochemistry and transmission electron microscopy. The contractile protein, tropomyosin (TM) was localized in the pericyte around the vessels of spiral ligament but little was seen around strial capillaries. Prostaglandin I2 (PGI2) is a vasodilatory substance produced ...

The blood supply of the adrenal gland in the common tree shrew (Tupaia glis) was studied by use of transmission electron microscopy and vascular corrosion cast/scanning electron microscopy techniques. It was found that the gland receives its blood supply from branches of the inferior phrenic, aorta and renal arteries. Upon ...

1. The effects of a purified micronized flavonoid fraction (S5682) on mean internal diameter and blood flow of arterioles and venules, as well as the functional capillary density (FCD) were evaluated in the hamster cheek pouch microvasculature before and after 90 min of total ischaemia. 2. Male hamsters were treated ...

A reproducible, rapid procedure for the determination of homocysteine, cysteine, and glutathione in human blood by micellar electrokinetic chromatography (MEKC) has been developed. Whole blood samples were deproteinized and centrifuged, and the supernatant was directly introduced into the capillary for analysis without further derivatization. Separations were performed using an uncoated ...

Observations of blood flow in microvascular networks have shown that the resistance to blood flow is about twice that expected from studies using narrow glass tubes. The goal of the present study was to test the hypothesis that a macromolecular layer (glycocalyx) lining the endothelial surface contributes to blood flow ...

The architecture of the fetal villous tree and its vasculature in the bovine placentome were studied in the second half of gestation using both conventional histology and histology of ink-filled blood vessels. These were compared with corrosion casts of plastic fillings of the vasculature, prepared for scanning electron microscopy. This ...

Electrical impedance tomographic spectroscopy measurements of the lungs are taken from nine normal subjects, in the frequency range 9.6 kHz-1.2 MHz. The results show that resistivity rho'FRC relative to functional residual capacity increases almost linearly with inspiration volume V, with the slope of the curve increasing with frequency f. Resistivity ...

The present study was performed to provide data to support the notion previously believed but not proved experimentally or theoretically, that blood vessels are formed by the selection of capillaries in the network. In an attempt to understand the mechanism of formation of blood vessel branching structures, the transformation of ...

The distribution of lymph capillaries and blood capillaries in the synovial membrane was examined immunohistologically with anti-human collagen IV antibody and anti-human von Willebrand factor in 26 human temporomandibular joint (TMJ) samples comprising discs with adjoining synovial membrane from 10 control TMJs and from 16 TMJs with internal derangement. Three ...

Whether the pulmonary vascular bed accommodates flow-induced increases in blood volume mainly through recruitment of previously unperfused capillaries or distension of already perfused vessels remains controversial. The modified first order reaction parameter of an enzyme and substrate, Amax/K(m), is, under nontoxic conditions, proportional to enzyme mass. Thus for ACE, an ...

To measure the amount of tissue factor released during specimen collection and its potential effect of shortening the prothrombin time, we measured tissue factor and prothrombin time in twenty-three paired venous and capillary blood samples from anticoagulated patients and in ten paired samples from controls. We also compared venous prothrombin ...

Increasing pulmonary blood flow and the associated rise in capillary perfusion pressure cause capillary recruitment. The resulting increase in capillary volume limits the decrease in capillary transit time. We hypothesize that small species with relatively high resting metabolic rates are more likely to utilize a larger fraction of gas-exchange reserve ...

The velocity of red blood cells (RBC) in individual capillaries of the rat cerebral cortex was assessed using direct, intravital video microscopy under normal conditions and during systemic hypoxia or hypercapnia. The movement of RBC in capillaries within 50-microm depth of the parietal cortex was visualized with the aid of ...

We investigated the sensitivity and specificity of perfusion and blood-pool scintigraphy in the detection of head and neck hemangiomas and evaluated their histopathologic types. METHODS: Perfusion and blood-pool scintigraphy with 99mTc-red blood cells (RBCs) or 99mTc-human serum albumin combined with DTPA (HSA-D) were used to evaluate 51 head and neck ...

In hamster cremaster muscle, capillary networks consist of anatomically invariant subunits termed modules [Berg, B. R., and I. H. Sarelius, Am. J. Physiol. 268 (Heart Circ. Physiol. 37): H1215-H1222, 1995]. To explore local coupling between blood flow and metabolism, we used micropipettes to stimulate five to six muscle fibers running ...

In brain cortex all capillaries are perfused with plasma at anyone time while the flow of blood cells is heterogeneous. Increased blood flow is associated with increased number of moving erythrocytes in the microcirculation, while capillary recruitment in its classical anatomical sense appears not to exist in the brain. Modulation ...

Capillary perfusion in the brain is characterized by an essentially continuous flow of erythrocytes and plasma in almost all capillaries. Rapid fluctuations and spatial heterogeneity or red blood cell (RBC) velocity (0.5-1.8 mm/s) within the capillary network are present. In addition, low-frequency (4-8 cpm) synchronous oscillations in RBC velocity in ...

Various manifestations of blood flow structuring were investigated in rabbit cerebral cortex capillaries, which possess the most narrow lumina of all parts of the body. Blood flow structuring in the capillaries was characterized by the presence of a stable and comparatively large parietal plasma layer, which changed insignificantly under control ...

As muscles are stretched, blood flow and oxygen delivery are compromised, and consequently muscle function is impaired. We tested the hypothesis that the structural microvascular sequellae associated with muscle extension in vivo would impair capillary red blood cell hemodynamics. We developed an intravital spinotrapezius preparation that facilitated direct on-line measurement ...

Individual pulmonary capillaries are not steadily perfused. By using in vivo microscopy, it can readily be demonstrated that perfusion continually switches between capillary segments and between portions of the network within a single alveolar wall. These changes in capillary perfusion occur even when upstream pressure and flow are constant. Flow ...

OBJECTIVE: The resistance to flow of individual human neutrophils flowing through smooth-walled glass capillary tubes at velocities ranging between 0 and 30 microns/s is measured for six different capillary tube diameters between 4.65 and 7.75 microns. METHODS: The experiments were performed with a micropipet manipulation system. The velocity of individual ...

OBJECTIVES: Determination of the local regulation of cutaneous blood flow through nutritive capillaries and through arteriovenous anastomoses of the pulp of the first toe in response to passively induced orthostatic blood pressure changes in normal subjects and in patients with occlusive atherosclerotic disease. MATERIAL: Six normal subjects, seven patients with ...

We describe results of a 3-year study in which 499 paired venous and capillary blood specimens, collected by fingerstick on the same day, were analyzed for lead (BPb) and erythrocyte protoporphyrin (EP). False-positive rates (FPRs) and the proportion of false positives were calculated at four BPb thresholds. At the 100 ...