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PubMed1999

Quantitative study of capillary density in the skin of the foot in peripheral vascular disease.

BACKGROUND: The aim of this study was to investigate possible differences in capillary density of the skin of the foot between normal subjects and patients with peripheral vascular disease. METHODS: Using in vivo video microscopy, a method was developed to measure the average capillary density (ACD) of the skin of the foot and toes. In a cross-sectional observational study, 21 patients with intermittent claudication and 23 patients with rest pain or ischaemic ulceration were compared with 19 age- and sex-matched controls. RESULTS: Mean(s.e.m). values of ACD of the foot were 33.7(1.9) and 34.4(1.7) per mm2 in the right and left sides respectively for controls, 31.2(1.8) per mm2 (P not significant) and 31.9(2.6) per mm2 (P not significant) in the symptomatic and contralateral sides respectively for patients with claudication, and 22.0(1.8) per mm2 (P < 0.001) and 24.3(1.7) per mm2 (P < 0.001) in the symptomatic and contralateral sides respectively for patients with rest pain or ulceration. CONCLUSION: Capillary density of the skin of the foot is significantly reduced in patients with arterial ulceration compared with that in patients with claudication and healthy subjects.

Adult↗
PubMed2003

Targeting dendritic cells with CD44 monoclonal antibodies selectively inhibits the proliferation of naive CD4+ T-helper cells by induction of FAS-independent T-cell apoptosis.

CD44 is a multifunctional adhesion molecule that has been shown to be a costimulatory factor for T-cell activation in vitro and in vivo. The aim of the present study was to expand these findings by characterizing the role of CD44 during dendritic cell (DC) antigen presentation to naive, resting T cells. Certain monoclonal antibodies (mAbs) directed against all CD44 isoforms (pan CD44), or against the epitope encoded by the alternatively spliced exon v4 (CD44v4), dose-dependently inhibited the capacity of murine DC to induce proliferation of naive alloreactive T cells. Preincubation of the T cells or DC with these CD44 mAbs revealed that the effect was dependent upon mAb binding to DC, but not to T cells. DC treated with anti-pan CD44 and anti-CD44v4 mAbs induced CD4+ T-cell apoptosis, as shown by annexin V staining and TdT-mediated biotin-dUTP nick-end labelling (TUNEL) assays. However, CD4+ T-cell apoptosis was not dependent on the Fas/Fas ligand (Fas/FasL) system, as DC from FasL-deficient (Gld) mice and T cells from Fas-deficient (Lpr) mice were still susceptible to apoptosis induced by CD44-treated DC. To investigate whether CD44 treatment of DC affects early T-cell/DC interactions, time-lapse video microscopy was performed using peptide-specific T cells from T-cell receptor (TCR) transgenic mice. Interestingly, calcium signalling in CD4+ T cells was significantly diminished following interaction with CD44 mAb-treated DC, but this was not observed in CD8+ T cells. Taken together, we found that perturbation of distinct epitopes of CD44 on DC interfere with early Ca2+ signalling events during the activation of CD4+ T cells, resulting in T-cell apoptosis.

Animals↗
PubMed1994

Action of brefeldin A on amphibian neurons: passage of newly synthesized proteins through the Golgi complex is not required for continued fast organelle transport in axons.

The relation between the availability of newly synthesized protein and lipid and the axonal transport of optically detectable organelles was examined in peripheral nerve preparations of amphibia (Rana catesbeiana and Xenopus laevis) in which intracellular traffic from the endoplasmic reticulum to the Golgi complex was inhibited with brefeldin A (BFA). Accumulation of fast-transported radio-labeled protein or phospholipid proximal to a sciatic nerve ligature was monitored in vitro in preparations of dorsal root ganglia and sciatic nerve. Organelle transport was examined by computer-enhanced video microscopy of single myelinated axons. BFA reduced the amount of radiolabeled protein and lipid entering the fast-transport system of the axon without affecting either the synthesis or the transport rate of these molecules. The time course of the effect of BFA on axonal transport is consistent with an action at an early step in the intrasomal pathway, and with its action being related to the observed rapid (< 1 h) disassembly of the Golgi complex. At a concentration of BFA that reduced fast-transported protein by > 95%, no effect was observed on the flux or velocity of anterograde or retrograde organelle transport in axons for at least 20 h. Bidirectional axonal transport of organelles was similarly unaffected following suppression of protein synthesis by > 99%. The findings suggest that the anterograde flux of transport organelles is not critically dependent on a supply of newly synthesized membrane precursors. The possibilities are considered that anterograde organelles normally arise from membrane components supplied from a post-Golgi storage pool, as well as from recycled retrograde organelles.

Animals↗
PubMed1995

Differential biological effects of K252 kinase inhibitors are related to membrane solubility but not to permeability.

K252a and K252b are related protein kinase inhibitors that, dependent on conditions, can either inhibit or potentiate the effects of neurotrophic factors. K252a, an ester, is more potent and more cytotoxic on intact cells than K252b, a carboxylic acid. To understand better why these drugs elicit different degrees of biological responses, we analyzed their hydrophobicity, cell permeability, and subcellular distribution. As judged by partitioning between organic and aqueous phases, both compounds are hydrophobic. The partition coefficients were 15.6:1 (organic/aqueous phases) for K252a and 4.4:1 for K252b. The ratio of fluorescence excitation at 352 nm to that at 340 nm for the K252 compounds in the organic alcohol 1-decanol versus water provides a simple assay of binding of these compounds to phospholipid membranes. This ratio shifted for K252a, but not K252b, in the presence of phospholipid vesicles, indicating that K252a dissolved in the hydrophobic interior of the membrane. Using quantitative video fluorescence microscopy, we found that K252a strongly labeled both Sf9 insect cells and PC12 rat pheochromocytoma cells, probably staining intracellular membranes. The uptake of K252a was rapid and apparently irreversible. K252b also quickly entered Sf9 and PC12 cells, but staining was much weaker. Hence, K252a and K252b are similar in that they both rapidly enter cells but greatly differ in their membrane solubility.

Animals↗
PubMed1998

Hemodynamics in nailfold capillaries of patients with systemic scleroderma: synchronous measurements of capillary blood pressure and red blood cell velocity.

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 determinants of microvascular function, namely capillary blood pressure and capillary red blood cell velocity, simultaneously in the same capillary. In patients with systemic scleroderma and in healthy volunteers matched for age and sex, capillary blood pressure was measured by direct cannulation and capillary red blood cell velocity by video microscopy. Capillary blood pressure and capillary red blood cell velocity were significantly lower in patients (14.27 +/- 4.34 mmHg, 230 +/- 310 microm per s) than in healthy controls (19.06 +/- 3.69 mmHg, p < 0.008, and 910 +/- 240 microm per s, p < 0.003) at an ambient temperature of 22 degrees C, whereas no significant difference in skin temperature was observed (23.7 +/- 0.9 degrees C vs 24.7 +/- 1.9 degrees C) and no occlusion of finger arteries was detected. Capillary blood pressure in enlarged capillaries did not differ from that in normal-shaped capillaries in the patients (correlation of diameter and capillary blood pressure, R2 = 0.04), which was also the case with capillary red blood cell velocity (R2 = 0.13). Capillary pulse pressure amplitude and capillary red blood cell velocity showed a strong correlation (R2 = 0.81), suggesting that the pressure gradient across the capillary loop, which is the driving force for capillary red blood cell velocity, was mainly dependent on precapillary resistance. These observations reflect the inadequate microvascular function in systemic scleroderma, which may be due mainly to a pathophysiologic functional increase in precapillary resistance, even at comfortable ambient temperatures.

Adult↗
PubMed1998

Peripheral microvascular parameters in the nephrotic syndrome.

BACKGROUND: Peripheral edema, in combination with severe proteinuria and low serum albumin levels, is pathognomonic of the nephrotic syndrome, yet the exact mechanism of its formation is unknown. Two of the most important of the factors in Starling's forces controlling fluid filtration across the capillary have hitherto not been studied in nephrotic subjects. METHODS: The hydrostatic capillary pressure at the finger nail-fold in actively nephrotic subjects and age and sex matched controls was studied, using direct puncture of the apex of the capillary under video microscopy, and a servonulling apparatus to give a direct measurement of capillary pressure. Capillary filtration capacity (CFC) at the calf was measured noninvasively by a modern derivative of the technique of mercury strain gauge plethysmography. Fifteen nephrotic subjects with a variety of underlying pathological lesions, and age matched controls were studied. RESULTS: Contrary to the assumption of the "overflow" hypothesis of edema formation, there was no evidence of capillary hypertension. The capillary pressure showed no difference between nephrotic subjects and controls: median (range) of 17.6 (12.0 to 24.2) compared with 17.3 (9.0 to 21.6) mm Hg, P = NS. CFC was significantly higher in nephrotic subjects than controls [5.23 (3.28 to 8.52) x 10(-3) versus 3.55 (2.43 to 5.28) x 10(-3) ml/min/100 g/mm Hg, P < 0.01]. CONCLUSIONS: An increase in CFC provides a potentially novel mechanism contributing at least in part to the formation of peripheral edema in the nephrotic syndrome.

Adult↗
PubMedDate not supplied

The hairless mouse ear: an in vivo model for studying wound neovascularization.

Microvascular ingrowth into damaged tissue is an essential component of the normal healing process. In fact, wound therapy is often aimed at promoting neovascularization. However, little is known about the mechanisms that regulate microvascular ingrowth into a healing wound. This limited knowledge is largely due to the lack of adequate models in which microvascular ingrowth can be quantitatively analyzed throughout the healing process. To address this deficiency, we developed a model in which a wound was created on the ear of the hairless mouse-a well established model for directly viewing and measuring skin microcirculation. While the animals were under ketamine and xylazine anesthesia, 2.25 mm diameter full-thickness wounds were created on the dorsum of hairless mouse ears down to but not including the cartilage (0.125 mm depth). With the use of video microscopy and computer-assisted digitized planimetry, the precise epithelial and neovascular wound edge was viewed and measured regularly throughout healing. Therefore, this model can provide objective data on wound epithelialization and neovascularization throughout healing. This model was used to examine the effect of topical wound agents on epithelialization and neovascularization. Differential effects by these anti-microbial agents on these two processes were observed, which suggests clinical implications for their use.

Journal Article↗
PubMedDate not supplied

Ketanserin accelerates wound epithelialization and neovascularization.

We investigated the acute effects of topical ketanserin, a 5-HT(2) (serotonin) receptor blocker, on wound epithelialization and vascularization with the use of the hairless mouse ear model. Varying concentrations of Ketanserin (0%, 0.2%, 2.0%, 20% weight/volume) were administered to standardized full-thickness skin wounds on the dorsum of the hairless mouse ear immediately after surgery and daily thereafter. With the use of video microscopy and computer-assisted planimetry, vascularization and epithelialization were traced every third day until the wounds were fully healed. Arteriole diameters at selected sites near the skin wound were measured before wound creation and after wounding. It was concluded that topically administered ketanserin significantly accelerates both the vascular (p < 0.001 at 2% and 20% concentrations) and epithelial (p < 0.001 at 20% concentration) rates of wound healing in full-thickness nonpathologic skin wounds. Vasodilation of terminal arterioles was not a major response to Ketanserin. Faster epithelialization was possibly due to direct effect of ketanserin on epithelial cells.

Journal Article↗
PubMed2003

An examination of calcium current function on heterotopic neurons in hippocampal slices from rats exposed to methylazoxymethanol.

PURPOSE: To study voltage-dependent calcium currents (VDCCs) on hippocampal heterotopic neurons by using whole-cell patch-clamp techniques in brain slices prepared from methylaxozymethanol (MAM)-exposed rats. METHODS: Whole-cell voltage-clamp recordings were obtained from visually identified neurons in acute brain slices by using an infrared differential interference contrast (IR-DIC) video microscopy system. Heterotopic neurons were compared with normotopic pyramidal cells in hippocampal slices from MAM-exposed rats or CA1 pyramidal neurons in slices from controls. RESULTS: Heterotopic neurons expressed a prominent VDCC, which exhibited a peak current maximum around -30 mV (holding potential, -60 mV) and an inactivation time constant of 48.2 +/- 2.4 ms (n = 91). VDCC peak current and inactivation time constants were similar for normotopic (n = 92) and CA1 pyramidal cells (n = 40). Pharmacologic analysis of VDCC, on heterotopic, normotopic, and CA1 pyramidal cells, revealed an approximately 70% blockade of peak Ca2+ current with nifedipine and amiloride (L- and T-type channel blockers, respectively). Inhibition of VDCC, for all three cell types, also was similar when more specific Ca2+ channel antagonists were used [e.g., omega-conotoxin GVIA (N-type), omega-agatoxin KT (P/Q-type), and sFTX-3.3 (P-type)]. VDCC modulation by norepinephrine (NE) or adrenergic receptor-specific agonists [clonidine (alpha2), isoproterenol (beta), and phenylephrine (alpha1)] was similar for heterotopic and CA1 pyramidal cells. CONCLUSIONS: Heterotopic neurons do not appear to exhibit Ca2+ channel abnormalities that could contribute to the reported hyperexcitability associated with MAM-exposed rats.

Animals↗
PubMed2001

Rarefaction of skin capillaries in patients with anginal chest pain and normal coronary arteriograms.

AIMS: Patients with arterial hypertension often have a reduction in capillary density (rarefaction) and a reduction in coronary flow reserve because of functional and structural alterations of the coronary microcirculation. Patients with chest pain and normal coronary arteriograms may have coronary microvascular dysfunction, but it is not known whether capillary rarefaction plays a role in the pathogenesis of this syndrome. The aim of this study was to compare capillary density in hypertensive and normotensive subjects with anginal chest pain and normal coronary arteriograms vs asymptomatic hypertensives and healthy controls. METHODS AND RESULTS: We studied 49 patients with typical anginal chest pain, positive exercise testing and normal coronary arteriograms; 22 were hypertensive and 27 were normotensive. We used intra-vital video-microscopy to examine the skin of the dorsum of the middle finger of the non-dominant hand before and after maximization of perfused capillaries with venous congestion. Mean capillary density was significantly lower in patients with chest pain and normal coronary arteriograms independent of their blood pressure level, compared to normotensive healthy controls. Differences were found both at baseline [51+/-2 (hypertensive) and 52+/-2 (normotensive) vs 65+/-2 (controls) per 0.56 mm(2) respectively], (P<0.0001) and after maximization [57+/-3 (hypertensive) and 59+/-2 (normotensive) versus 75+/-3 (controls) respectively] (P<0.0001). CONCLUSIONS: Skin capillary density is significantly lower in patients with chest pain and normal coronary arteriograms compared to normotensive controls. The pathophysiological importance of capillary rarefaction in patients with chest pain and normal coronary arteriograms remains unknown. Further studies are needed to determine whether the abnormality is associated with myocardial flow disturbances such that the findings can be extended to the heart.

Capillaries↗
PubMed2001

Alterations in vesicle transport and cell polarity in rat hepatocytes subjected to mechanical or chemical cholestasis.

BACKGROUND & AIMS: The molecular mechanisms that contribute to the cholestatic condition in hepatocytes are poorly defined. It has been postulated that a disruption of normal vesicle-based protein trafficking may lead to alterations in hepatocyte polarity. METHODS: To determine if vesicle motility is reduced by cholestasis, hepatocytes cultured from livers of bile duct ligation (BDL)- or ethinyl estradiol (EE)-injected rats, were viewed and recorded by high-resolution video microscopy. Cholestatic hepatocytes were analyzed by phalloidin staining and electron microscopy. Functional analysis was done by the sodium fluorescein sequestration assay. RESULTS: In cholestatic hepatocytes, there was a significant decrease in the number of motile cytoplasmic vesicles observed compared with control cells. Further examination of cells from BDL- or EE-treated livers revealed the presence of numerous large intracellular lumina. More than 24% of cells in BDL-treated livers and 19% of cells in EE-treated livers displayed these structures, compared with 1.1% found in control hepatocytes. Phalloidin staining of hepatocytes showed a prominent sheath of actin surrounding the lumina, reminiscent of those seen about bile canaliculi. Electron microscopy revealed that these structures were lined by actin-filled microvilli. Further, these pseudocanaliculi perform many of the functions exhibited by bona fide canaliculi, such as sequestering sodium fluorescein. CONCLUSIONS: Both mechanically and chemically induced cholestasis have substantial effects on vesicle-based transport, leading to marked disruption of hepatocellular polarity.

Animals↗
PubMed2001

Online Internet-based robotic telepathology in the diagnosis of neuro-oncology cases: a teleneuropathology feasibility study.

This feasibility study examined the diagnostic accuracy of Internet-based dynamic-robotic telepathology using neuropathology cases. Randomly, 83 cases were selected from the routine diagnostic workload of the Neurosurgical Pathology Laboratory in Poznan, Poland. Telepathology diagnoses were compared with conventional paraffin section diagnosis. The neuropathologists, operating a robotically controlled motorized microscope over the Internet from 3 different Polish cities, individually reviewed the cases using computer workstations. Viewing times ranged from 2 minutes 54 seconds to 32 minutes 12 seconds per case. The mean diagnostic accuracy for telepathology diagnosis was 95%, with 2 of 3 observers achieving 100% diagnostic accuracy. Image quality was judged to be sufficient for correct evaluation, and the viewing times required to establish a final diagnosis by remote video microscopy were acceptable. Generally, user acceptance of robotic telepathology was high.

Adolescent↗
PubMed2001

Characteristics of a telecytology consultation service.

Although numerous reports describe the application of remote video microscopy to pathologic diagnosis (telepathology), only a few address some of the special issues surrounding remote cytologic diagnosis (telecytology). These studies have generally suggested a high correlation between telecytologic diagnoses and those arising from direct examination of the glass slides, but factors affecting the clinical utility of routine cytologic diagnosis have not been examined. In this report, we describe our experience in telecytologic consultation on 99 cases seen at the Armed Forces Institute of Pathology between October 1995 and November 1999. The mean time between receipt of the telecytologic images and the contributor receipt of the faxed report was 9.9 hours (median, 5.13 hours). Using stringent criteria for agreement, we find fair to good (48%) concordance between the contributor's impression and the consultant's opinion. The concordance between the consultant's telecytologic diagnosis and the subsequent glass slide diagnosis is imperfect; in 8 (31%) of 26 cases in which the glass slide was sent after the telecytology consultation, a minor discrepancy between these diagnoses was found. No major discrepancies were found between the consultant's telecytologic and glass slide diagnoses.

Cytodiagnosis↗
PubMed2000

Acute effect of a dried ethanol-water extract of garlic on the microhaemovascular system of the skin.

In the present study, the acute vasoactive effect of a dried hydrophilic extract of garlic with 600 mg active substance (Alliosan) was investigated in 10 healthy volunteers. Laser-Doppler fluxmetry, video capillary microscopy and transcutaneous partial pressure of oxygen measurements were used for the objective assessment of functional and morphological parameters. An increase in perfusion could be demonstrated by these means. This was based on an increase in erythrocyte flow velocity of up to 2 h duration, which was mainly due to vasodilation in both arterial and venous vessels. A change in transcutaneous partial pressure of oxygen or an influence on sympathetically-mediated vasomotor reflexes could not be demonstrated. Furthermore, there was no evidence of an influence on reactive hyperaemia after controlled hyperthermia. The test substance was shown to increase the cutaneous microperfusion.

Adult↗
PubMed2000

Intracellular trafficking and regulation of canalicular ATP-binding cassette transporters.

The bile canaliculus contains at least four ATP-binding cassette (ABC) proteins responsible for ATP-dependent transport of bile acids (spgp), nonbile acid organic anions (mrp2), organic cations (mdr1), and phosphatidylcholine (mdr2). Other ABC transporters (including mrp3) have also been partially localized to the canaliculus; however, their function has not been fully delineated. The specific amount and function of spgp and mrp2 in the canalicular membrane increases in response to taurocholate and cAMP. The mechanism involves increased recruitment of spgp and mrp2 from Golgi to the canalicular membrane by a microtubular and PI3 kinase-dependent vesicular trafficking system. Because the effects of taurocholate and cAMP summate, two distinct pathways are proposed. Mdr family members traffic either directly to the apical plasma membrane or, in the case of spgp, through a separate intracellular pool(s); in either case, there is no direct evidence for transcytosis of ABC transporters from Golgi to basolateral plasma membrane and subsequently to the canalicular plasma membrane. Direct transfer from Golgi to apical membrane was demonstrated by in vivo pulse labeling, in vitro membrane localization, and on-line video microscopy in WIFB9 cells that were stably transfected with mdr1-GFP. A critical role for 3'-phosphoinositide products of PI3 kinase was demonstrated in the intracellular trafficking of canalicular ABC transporters and for optimal transporter activity within the canalicular membrane. These studies suggest that many intracellular components, including ATP, Ca2+, numerous GTPases, microtubules, cytoplasmic motors, and other unknown factors, are required for physiologic regulation of ABC transporter traffic from Golgi to the canalicular membrane. Defects in this complex system are postulated to produce an "intrahepatic traffic jam" that results in defective ABC transporter function in the canalicular membrane and, consequently, in cholestasis.

ATP-Binding Cassette Transporters↗
PubMed2001

[Small bowel transplantation as an experimental and clinical replacement procedure].

Small bowel transplantation as an experimental and clinical replacement procedure. The routine use of human small bowel isografts as a treatment for mucosal defects, e. g. in the hypopharynx, demonstrates clearly that early surgical problems with this procedure have almost been solved. However, human small bowel allografts show a high risk for complications after transplantation. They provoke severe rejection episodes in the recipients which have to be treated with high-dose immunosuppression. These rejection episodes are of major interest for our own experimental research in rats: Video-microscopy (clinically established as zoom-endoscopy) makes early recognition and immediate therapy of these events possible. Concommittant liver transplantation from the identical donor even eliminate them. However, further research of the specific small bowel immune system is needed, to make this organ transplantation even clinically more successful.

Adult↗
PubMed2006

[Ca2+-signaling in smooth muscles cells of the airways in T-bet knock-out mice].

BACKGROUND: Airway smooth muscle cells (ASMC) play a key role in bronchial hyperresponsiveness (BHR). A major component of the signalling cascade leading to ASMC contraction is calcium. T-bet knock-out (KO) mice show the key features of allergic asthma such as a shift towards T (H2)-lymphocytes and display a broad spectrum of asthma-like histological and functional characteristics. In this study, we aimed at investigating whether Ca (2+)-homeostasis of ASMC is altered in T-bet KO-mice as an experimental model of asthma. METHODS: Lung slices of 100 to 200 microm thickness were obtained from T-bet KO- and wild-type mice. Airway contractions in response to acetylcholine (ACH) were measured by video-microscopy and Ca (2+)-signaling in single ASMC of lung slices was assessed using two-photon microscopy. RESULTS: Airways from T-bet KO-mice showed increased baseline airway tone (BAT) and BHR compared to those of wild-type mice. The increased BAT was correlated with an increased incidence of spontaneous changes in intracellular Ca (2+)-concentrations, whereas BHR correlated with higher ACH-induced Ca (2+)-transients and an increased proportion of ASMC showing Ca (2+)-oscillations. Emptying intracellular Ca (2+)-stores using caffeine or cyclopiazonic acid induced higher Ca (2+)-elevations in ASMC from T-bet KO compared to wild-type mice. CONCLUSIONS: Altered Ca (2+)-homeostasis of ASMC contributes to increased BAT and BHR in lung slices from T-bet KO mice as a murine asthma model. We propose that a higher Ca (2+)-content of the intracellular Ca (2+)-stores is involved in the pathophysiology of these changes.

Animals↗
PubMed2004

Influence of a depletion interaction on dynamical heterogeneity in a dense quasi-two-dimensional colloid liquid.

We report the results of digital video microscopy studies of the large particle displacements in a quasi-two-dimensional binary mixture of large (L) and small (S) colloid particles with diameter ratio sigma(L)/sigma(S)=4.65, as a function of the large and small colloid particle densities. As in the case of the one-component quasi-two-dimensional colloid system, the binary mixtures exhibit structural and dynamical heterogeneity. The distribution of large particle displacements over the time scale examined provides evidence for (at least) two different mechanisms of motion, one associated with particles in locally ordered regions and the other associated with particles in locally disordered regions. When rhoL*=Npisigma(L) (2)/4A< or =0.35, the addition of small colloid particles leads to a monotonic decrease in the large particle diffusion coefficient with increasing small particle volume fraction. When rhoL* > or =0.35 the addition of small colloid particles to a dense system of large colloid particles at first leads to an increase in the large particle diffusion coefficient, which is then followed by the expected decrease of the large particle diffusion coefficient with increasing small colloid particle volume fraction. The mode coupling theory of the ideal glass transition in three-dimensional systems makes a qualitative prediction that agrees with the initial increase in the large particle diffusion coefficient with increasing small particle density. Nevertheless, because the structural and dynamical heterogeneities of the quasi-two-dimensional colloid liquid occur within the field of equilibrium states, and the fluctuations generate locally ordered domains rather than just disordered regions of higher and lower density, it is suggested that mode coupling theory does not account for all classes of relevant fluctuations in a quasi-two-dimensional liquid.

Journal Article↗