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At least 973 records · Page 54Linked to original sources
PubMed2002

Protoplasmic pH modifies water and solute transfer in beta vulgaris root vacuoles.

Volume changes were studied in Beta vulgaris storage root vacuoles, using video microscopy, when exposed to hypotonic conditions. The osmotic gradient was either step-applied or progressively imposed in perfusion experiments. Preincubation at low pH (6.6) or with HgCl2 strongly reduced the vacuoles' water permeability, measured in step experiments. Furthermore, the volumetric response depended on the rate with which the aniso-osmotic condition was established. In perfusion experiments a "plateau value" (osmotic equilibrium or steady-state volume value) was observed, which was significantly lower than the theoretically expected one. Furthermore, if vacuoles were preincubated in presence of HgCl2 or at low pH and then the hypo-osmotic challenge was applied in perfusion experiments, a still lower "plateau value" was observed. This reduction was concentration-dependent and completely reversible. In these conditions, when HgCl2 concentration was 300 mM or medium pH was 6.6, the volume change was abolished. In other experiments, when urea iso-osmotically replaced mannitol, a reversible, pH-dependent volumetric response was observed. These results can be interpreted accepting that 1) mercury-sensitive water channels, present in the studied structure, were blocked by low pH during the hypo-osmotic challenge; 2) modification of water permeability prevents excessive swelling during the osmotic shock; 3) the effectiveness of this last mechanism depended on the osmotic challenge rate; and 4) additionally, urea reflection coefficients were also modified by reduced medium pH.

Beta vulgaris↗
PubMed2004

Volume-sensitive Cl- current in bovine adrenocortical cells: comparison with the ACTH-induced Cl- current.

In a previous study performed on zona fasciculata (ZF) cells isolated from calf adrenal glands, we identified an ACTH-induced Cl- current involved in cell membrane depolarization. In the present work, we describe a volume-sensitive Cl- current and compare it with the ACTH-activated Cl- current. Experiments were performed using the whole-cell patch-clamp recording method, video microscopy and cortisol-secretion measurements. In current-clamp experiments, hypotonic solutions induced a membrane depolarization to -22 mV. This depolarization, correlated with an increase in the membrane conductance, was sensitive to different Cl- channel inhibitors. In voltage-clamp experiments, hypotonic solution induced a membrane current that slowly decayed and reversed at -21 mV. This ionic current displayed no time dependence and showed a slight outward rectification. It was blocked to variable extent by different conventional Cl- channel inhibitors. Under hypotonic conditions, membrane depolarizations were preceded by an increase in cell volume that was not detected under ACTH stimulation. It was concluded that hypotonic solution induced cell swelling, which activated a Cl- current involved in membrane depolarization. Although cell volume change was not observed in the presence of ACTH, biophysical properties and pharmacological profile of the volume-sensitive Cl- current present obvious similarities with the ACTH-activated Cl- current. As compared to ACTH, hypotonic solutions failed to trigger cortisol production that was weakly stimulated in the presence of high-K+ solution. This shows that in ZF cells, membrane depolarization is not a sufficient condition to fully activate secretory activities.

Adrenocorticotropic Hormone↗
PubMed2000

Evidence for a calcium-sensing receptor in the vascular smooth muscle cells of the spiral modiolar artery.

The vascular diameter of the gerbilline spiral modiolar artery has been shown to depend on the presence of extracellular Ca(2+) but it remained unknown whether the smooth muscle cells of this arteriole contain a Ca(2+) sensing receptor (CaSR). The cytosolic Ca(2+) concentration ([Ca(2+)](i)) was monitored as fluo 3 fluorescence and the vascular diameter was measured by video-microscopy in isolated in vitro superfused spiral modiolar arteries. RT-PCR was used to probe for the presence of CaSR transcripts. Increasing the extracellular Ca(2+) concentration ([Ca(2+)](o)) from 1 to 10 mm caused a biphasic increase in [Ca(2+)](i) that was paralleled by a vasoconstriction. The initial rate of this vasoconstriction, 2.01 +/- 0.07 microm/sec (n = 131), was inhibited when cytosolic Ca(2+) stores were presumably depleted with thapsigargin (IC(50) = 3 x 10(-9) m, n = 26) or ryanodine (IC(50) = 4 x 10(-8) m, n = 25) or when PLC was inhibited by 10(-6) m U73122 (n = 8). The initial rate of this constriction was not affected by the L-type Ca(2+) channel blocker 10(-6) m nifedipine (n = 5), by 10(-6) m U73343 (n = 6), which is the inactive analogue of U73122, by the T-type Ca(2+) channel blocker 10(-6) Gd(3+) (n = 6) or the Na(+)/Ca(2+) exchanger blocker 10(-4) m Ni(2+) (n = 5). The agonist rank potency order was Gd(3+) > Ni(2+) > Ca(2+) >> neomycin = Mg(2+). Analysis of RNA isolated from the SMA revealed a RT-PCR product of the appropriate size for the CaSR (448 bp). Sequence analysis of the amplified cDNA fragment revealed a 94-96% amino acid identity compared to other CaSRs. These results demonstrate that the spiral modiolar artery contains a CaSR, which is most likely located in the vascular smooth muscle cells.

Arteries↗
PubMed2000

Water permeability in rat oocytes at different maturity stages: aquaporin-9 expression.

Important functional and structural modifications occur in mammalian oocytes during their arrival to maturity. In this process, oocytes switch from a high activity level, implying an important metabolic rate and a coordinated movement of water and solutes, to a lower functional state. The aim of this work was to study the mechanisms involved in water movements during oocyte arrival to maturity. Volume changes, induced by an osmotic gradient, were followed by video microscopy in rat oocytes. The water osmotic permeability (P(osm)) of immature oocytes (proestrus) was sensitive to HgCl(2) and phloretin. In contrast, mature oocytes (estrus) had a reduced P(osm) that was not sensitive to these compounds. When proestrus oocytes were incubated in vitro at 37 degrees C they spontaneously arrived at maturity and its P(osm) decreased between four and six hours of incubation. RT-PCR experiments were performed using specific primers for all rat aquaporins that had been cloned. We found that aquaporin-9 transcript (AQP9) is present in proestrus oocytes but not in estrus oocytes. AQP9 has been recently described as a "broad selective channel" responsible for solute and water transfers in highly active cells. Our experiments showed that proestrus oocytes, but not estrus, are permeable to mannitol. It is concluded that during the process of maturation, P(osm) decreases and AQP9 transcripts disappear. We report here the first study correlating water permeability and aquaporin mRNA expression in mammalian oocytes.

Animals↗
PubMed1996

Short-chain fatty acid (SCFA) volume regulation in proximal and distal rabbit colon is different.

SCFAs increase the volume of many different cell types rarely exposed to significant concentrations of these weak electrolytes. SCFAs swell isolated cells from colonic carcinoma cell lines, but the-mechanism(s) of volume regulation in normal colonocytes, which are generally exposed to > 100 mM SCFAs, has not been well characterized. AIMS. To determine the effect of SCFAs on volume regulation in proximal and distal rabbit colonocytes. METHODS. Isolated colonocytes were plated on coverslips and placed in a perfusion apparatus that permitted fluid changes. Cells were continuously monitored by video-microscopy; volume was estimated by measured changes in the radius of individual cells. RESULTS. Distal colonocytes (DC) consistently had a slightly greater basal volume than proximal colonocytes (PC): [14.2 pl/fl:9.8 pl/fl] In HEPES-buffered solutions, an isotonic change to a 90 mM NaCl/50 mM Na propionate solution elicited a significant increase in cell volume within 10 min, but no noticeable regulatory volume decrease over 30 min: V/Vo in DC: 1.29 +/- .09; in PC: 1.25 +/- .05. In HCO3-buffered solutions, 50 mM PROP caused significantly greater cell swelling; in DC: 1.74 +/- .21; in PC: 1.52 +/- .08. In DC both amiloride and EIPA blocked the SCFA-induced increase in cell volume. A hypotonic challenge confirmed that these cells were capable of swelling. In contrast, amiloride did not significantly inhibit SCFA-induced swelling in PC: control, 1.25 +/- .05; amiloride, 1.36 +/- .10. Cell volume increased in PC perfused with an isosmotic 50 mM propionate, Na-free solution: 1.22 +/- .04. CONCLUSIONS. (i) SCFAs induce significant cell swelling, but no regulatory volume decrease, in isolated colonocytes; (ii) HCO3 augments SCFA-induced cell swelling; (iii) volume increase in DC is dependent on Na-H exchange, but in PC appears to be Na-independent. SIGNIFICANCE. There are fundamental differences in how proximal and distal colon respond to isosmotic volume challenge of SCFAs.

Animals↗
PubMed1997

Intracellular acidification induces Cl/HCO3 exchange activity in the basolateral membrane of beta-intercalated cells of the rabbit cortical collecting duct.

High speed video imaging microscopy and the pH-sensitive fluorophore2',7',-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) were used to examine acid-base functions of beta-intercalated cells of the rabbit cortical collecting duct. The presence of intercalated cells was established and the properties of apical and basolateral acid-base transporters assessed by monitoring cell pH during acid loading and luminal and basolateral ion substitutions. We showed that treatment of beta-intercalated cells with ammonium chloride (20 mm) induced a profound decrease of their intracellular pH from 6.98 +/- 5.93 +/- 0.08. pH recovery occurred after different lag periods ranging between 2 to 15 min (0.22 +/- 0. 04 dpH/dt). We demonstrated that this pH recovery mechanism was independent of basolateral Na+ and apical HCO-3 and K+. It was also not affected by apical and basolateral addition of NEM, by basolateral DIDS and by apical application of the H-KATPase inhibitor SCH28080. The process of pH recovery was however, critically dependent on basolateral HCO-3. These results are best explained by acid-induced insertion and/or activation of chloride-bicarbonate exchangers that are functional properties with their apical analogues.

Animals↗
PubMed2003

Interaction of nutrient limitation and protozoan grazing determines the phenotypic structure of a bacterial community.

We examined the impact of nutrient conditions (carbon and phosphorus limitation) and grazing by protozoans on the phenotypic community structure of freshwater bacteria in continuous culture systems. Lakewater bacteria were grown on mineral medium, which was supplemented with glucose and amino acids and adjusted by different phosphorus concentrations to achieve either carbon or phosphorus limitation. Each nutrient treatment was inoculated with the same bacterial community and consisted of a nongrazing and a grazing treatment, to which the heterotrophic nanoflagellates Spumella sp. and Ochromonas sp. were added. We found that nutrient conditions alone resulted in differences in the phenotypic structure of the bacterial community: small and motile bacteria dominated under C limitation while large, elongated, and capsulated bacteria were characteristic for P limitation. The genotypic community composition as measured by T-RFLP (terminal restriction fragment length polymorphism) was not severely influenced by the two nutrient treatments. In the presence of flagellate predators, grazing-resistant bacteria developed under both nutrient conditions, but with different survival mechanisms: highly motile bacteria prevailed under C limitation, whereas the P-limited grazing treatment was dominated by filamentous forms. T-RFLP analysis revealed only moderate changes in bacterial community composition due to grazing, which were most pronounced under P limitation. Analysis by video microscopy revealed that high swimming speed is an efficient nonmorphological survival mechanism for bacteria to reduce the capture success of the flagellate predator. The rejection of optimal-sized, nonmotile bacteria under P limitation suggests the importance of other nonmorphological, surface-located cell properties. Our results illustrate that the realized mechanisms of grazing resistance are linked to the actual limitation conditions, and that the combined effects of nutrient limitation and grazing are major determinants of bacterial community structure.

Animals↗
PubMed2006

Feeding characteristics of an amoeba (Lobosea: Naegleria) grazing upon cyanobacteria: food selection, ingestion and digestion progress.

Bacterivory by heterotrophic nanoflagellates and ciliates has been widely studied in aquatic environments, but data on the grazing of amoebae, are still scarce. From the water samples of Dianchi Lake (Kunming, Yunnan Province, China), we isolated an amoeba, designated as Naegleria sp. strain W2, which had potent grazing effects on some kind of cyanobacteria. The food selection mechanism and the digestion process of the amoeba were investigated in batch experiments. Predation experiments showed that filamentous cyanobacteria (e.g., Anabaena, Cylindrospermum, Gloeotrichia, and Phormidium) were readily consumed, with clearance rates ranging from 0.332 to 0.513 nL amoeba(-1) h(-1). The tight threads (Oscilltoria) and aggregates (Aphanizomenon) could not be ingested; however, their sonicated fragments were observed inside food vacuoles, suggesting that their morphologies prevent them from being ingested. Live video microscopy noted that unicellular Chroococcaceae (e.g., Synechococcus, Aphanocapsa, and Microcystis) were excreted after ingestion, indicating that food selection takes place inside food vacuoles. To determine whether the tastes or the toxins prevented them from being digested, heat-killed cells were retested for predation. Digestion rates and ingestion rates of the amoebae for filamentous cyanobacteria were estimated from food vacuole content volume. Through a "cold-chase" method, we found that the food vacuole contents declined exponentially in diluted amoebae cells, and digestion rates were relatively constant, averaging about 1.5% food vacuole content min(-1) at 28 degrees Celsius. Ingestion strongly depended on the satiation status of the amoebae, starved amoebae fed at higher rates compared with satiated amoebae. Our results suggest that the food selection and food processing mechanisms of the amoeba are similar to those of interception feeding flagellates; however, filamentous cyanobacteria cannot obtain a refuge under the grazing pressure of phagotrophic amoebae, which may widen our knowledge on the grazing of protists.

Amoeba↗
PubMed1999

Apoptotic cell death induced by baccatin III, a precursor of paclitaxel, may occur without G(2)/M arrest.

PURPOSE: Paclitaxel has been demonstrated to possess significant cell-killing activity in a variety of tumor cells by induction of apoptosis, but the mechanism by which paclitaxel leads to cell death and its relationship with mitotic arrest is not entirely clear. In this study, baccatin III, a synthetic precursor of paclitaxel, was used to analyze whether paclitaxel-induced apoptosis can be a separate event from microtubule bundling and G(2)/M arrest. METHODS: Several different methods including DNA fragmentation, flow cytometric analyses, TdT-mediated dUTP nick end labeling (TUNEL) and time-lapse video microscopy were used to analyze apoptotic cell death induced by baccatin III and its possible correlation with cell cycle distribution. RESULTS: Our results demonstrated that baccatin III could also cause apoptotic cell death in both BCap37 (a human breast cancer cell line) and KB cells (derived from human epidermoid carcinoma), but had less effect on microtubule bundling and G(2)/M arrest. Furthermore, we demonstrated that most apoptotic events induced by baccatin III were not coupled with G(2)/M arrest. Instead, these apoptotic events occurred predominantly in the cells in other phases of the cell cycle. CONCLUSION: Baccatin III, which contains the core taxane ring, is the fundamental piece of paclitaxel structure. The finding of baccatin III-induced apoptosis independent of cell cycle arrest, on the one hand, implies that the core taxane ring may play a critical role in inducing cell death and, on the other hand, suggests that paclitaxel might induce apoptosis from other phases of the cell cycle by a similar mechanism.

Alkaloids↗
PubMed2003

Stochastic models for cell motion and taxis.

Certain biological experiments investigating cell motion result in time lapse video microscopy data which may be modeled using stochastic differential equations. These models suggest statistics for quantifying experimental results and testing relevant hypotheses, and carry implications for the qualitative behavior of cells and for underlying biophysical mechanisms. Directional cell motion in response to a stimulus, termed taxis, has previously been modeled at a phenomenological level using the Keller-Segel diffusion equation. The Keller-Segel model cannot distinguish certain modes of taxis, and this motivates the introduction of a richer class of models which is nevertheless still amenable to statistical analysis. A state space model formulation is used to link models proposed for cell velocity to observed data. Sequential Monte Carlo methods enable parameter estimation via maximum likelihood for a range of applicable models. One particular experimental situation, involving the effect of an electric field on cell behavior, is considered in detail. In this case, an Ornstein- Uhlenbeck model for cell velocity is found to compare favorably with a nonlinear diffusion model.

Algorithms↗
PubMed2000

Ball tonometry: a rapid, nondestructive method for measuring cell turgor pressure in thin-walled plant cells.

In this article we describe a new method for the determination of turgor pressures in living plant cells. Based on the treatment of growing plant cells as thin-walled pressure vessels, we find that pressures can be accurately determined by observing and measuring the area of the contact patch formed when a spherical glass probe is lowered onto the cell surface with a known force. Within the limits we have described, we can show that the load (determined by precalibration of the device) divided by the projected area of the contact patch (determined by video microscopy) provides a direct, rapid, and accurate measure of the internal turgor pressure of the cell. We demonstrate, by parallel measurements with the pressure probe, that our method yields pressure data that are consistent with those from the pressure probe. Also, by incubating target tissues in stepped concentrations of mannitol to incrementally reduce the turgor pressure, we show that the pressures measured by tonometry accurately reflect the predicted changes from the osmotic potential of the bathing medium. The advantages of this new method over the pressure probe are considerable, however, in that we can move rapidly from cell to cell, taking measurements every 20 s. In addition, the nondestructive nature of the method means that we can return to the same cell repeatedly for periodic pressure measurements. The limitations of the method lie in the fact that it is suitable only for superficial cells that are directly accessible to the probe and to cells that are relatively thin walled and not heavily decorated with surface features. It is also not suitable for measuring pressures in flaccid cells.

Cell Physiological Phenomena↗
PubMed2001

Serotonin-induced human coronary microvascular contraction during acute myocardial ischemia is blocked by COX-2 inhibition.

Since serotonin (5-HT) is implicated in exacerbating acute coronary syndromes, we studied the reactivity of atrial coronary arterioles (70-140 microm) of atherosclerotic patients undergoing cardiac surgery to 5-HT, substance P (Sub P), and sodium nitroprusside by video-microscopy. Before ischemia, 5-HT-induced relaxation was not affected by NS398 (cyclooxygenase inhibitor), H2O2 or U63557A (thromboxane A2 synthase inhibitor), but was reduced by L-NNA. 5-HT elicited a potent contractile response after ischemia that was inhibited by NS398, Indo, and U63557A. While Sub P relaxation was decreased after ischemia, SNP relaxation was unchanged. The mRNA steady-state levels of NOS-3, NOS-2, prostacyclin synthase, and COX- 1 were not altered by ischemia. COX-2 mRNA and protein levels (Westernblotting), however, were increased (mean +/- SEM) 2.4 +/- 0.4 and 3.2 +/- 0.7 fold, respectively, in ischemic atrium corroborating with the immunohistochemistry of atrial tissue. It is concluded that myocardial ischemia enhanced contractile response of coronary arterioles to 5-HT maybe due to the stimulated prostaglandin release (likely thromboxane A2) secondary to induction of COX-2 expression. These findings may have implications regarding the cause of coronary spasm during acute myocardial ischemia.

Aged↗
PubMed1999

Protein phosphotyrosine phosphatase inhibitors suppress regulatory volume decrease and the volume-sensitive Cl- conductance in mouse fibroblasts.

The effects of the protein tyrosine phosphatase (PTP) inhibitors, pervanadate, monoperoxo(picolinato)- oxo-vanadate(V) [mpV(pic)] and dephostatin, on regulatory volume decrease (RVD) and the volume-sensitive Cl- current in mouse L-fibroblasts were studied with the aid of video microscopy and the whole-cell patch-clamp technique. The RVD induced by the hyposmotic shift from 300 to 150 mosmol/l, was strongly suppressed in cells that had been pre-incubated in pervanadate (25 microM) or in mpV(pic) (10 microM), or subjected to extracellular application of dephostatin (20 microM). The acceleration in RVD caused by gramicidin (0.5 microM) was also slowed down by pervanadate pre-treatment, suggesting that the PTP inhibitors affected the volume-sensitive Cl- conductance. Inhibition of the volume-sensitive Cl- current by pervanadate (25 microM) pre-treatment and by acutely applied dephostatin (20 microM) was confirmed in the whole-cell experiments (by @70% and by @50%, respectively). Both pervanadate and dephostatin inhibited the outward and inward Cl- currents equally, which suggests that only the number of open channels was affected. The amplitude of the Cl- current decreased slowly during application of dephostatin and did not recover after its termination. We conclude that in mouse L-fibroblasts, similar to bovine chromaffin cells, inhibition of PTPs results in the suppression of both RVD and the volume-sensitive Cl- current.

Animals↗
PubMed1999

Migration of transformed renal epithelial cells is regulated by K+ channel modulation of actin cytoskeleton and cell volume.

Migration of transformed renal epithelial (MDCK-F) cells depends on the polarized activity of a Ca2+-sensitive K+ channel (IK channel; Pflügers Arch 432:R87-R93, 1996). This study was aimed at elucidating the functional link between the IK channel and the actin cytoskeleton which is required for cell locomotion. We monitored migration of MDCK-F cells with video microscopy, quantified filamentous actin with phalloidin binding, and measured the intracellular Ca2+ concentration ([Ca2+]i) with the fluorescent dye fura-2/AM. We compared the effects of IK channel activation or inhibition with those of hypotonic swelling or hypertonic shrinkage. IK channel inhibition with charybdotoxin (CTX) or cell swelling (omission of up to 50 mmol/l NaCl) as well as IK channel activation with 1-ethyl-2-benzimidazolinone (1-EBIO) or cell shrinkage (addition of up to 100 mmol/l mannitol) reduce the rate of migration dose-dependently by up to 80%, i.e., to the same extent as cytochalasin D. Inhibition of migration is accompanied either by actin depolymerization (CTX and cell swelling) or by actin polymerization (1-EBIO and cell shrinkage). Changes of migration and phalloidin binding induced by CTX and cell swelling or by 1-EBIO and cell shrinkage, respectively, are linearly correlated with each other. CTX and cell swelling elicit a rise of [Ca2+]i whereas 1-EBIO and cell shrinkage induce a slight decrease of [Ca2+]i in most MDCK-F cells. Taken together IK-channel-dependent perturbations of cell volume and anisotonicity elicit virtually identical effects on migration, actin filaments and [Ca2+]i. We therefore suggest that cell volume - possibly via [Ca2+]i - is the link between IK channel activity, actin filaments and migration. We propose a model for how temporal and local changes of cell volume can support the migration of MDCK-F cells.

Actins↗
PubMed2005

Morphogenetic movements during cranial neural tube closure in the chick embryo and the effect of homocysteine.

In order to unravel morphogenetic mechanisms involved in neural tube closure, critical cell movements that are fundamental to remodelling of the cranial neural tube in the chick embryo were studied in vitro by quantitative time-lapse video microscopy. Two main directions of movements were observed. The earliest was directed medially; these cells invaginated into a median groove and were the main contributors to the initial neural tube closure. Once the median groove was completed, cells changed direction and moved anteriorly to contribute to the anterior neural plate and head fold. This plate developed into the anterior neuropore, which started to close from the 4-somite stage onwards by convergence of its neural folds. Posteriorly, from the initial closure site onwards, the posterior neuropore started to close almost instantaneously by convergence of its neural folds. Homocysteine is adversely involved in human neural tube closure defects. After application of a single dose of homocysteine to chick embryos, a closure delay at the initial closure site and at the neuropores, flattening of the head fold and neural tube, and a halt of cell movements was seen. A possible interference of Hcy with actin microfilaments is discussed.

Actin Cytoskeleton↗
PubMed1999

Release of merozoites from Plasmodium falciparum-infected erythrocytes could be mediated by a non-explosive event.

Little is known about the molecular mechanism underlying the release of merozoites from malaria-infected erythrocytes. In the present study, video microscopy was carried out, and images throughout the process of merozoite release from Plasmodium falciparum-infected erythrocytes were digitized and analyzed. Merozoites were shown to escape from the infected host cell in about 1 s through a single site of the infected erythrocyte membrane, whose dimension was estimated to be 2.5 microm. Merozoites were released together with the residual body containing hemozoin, leaving behind a membranous structure that persisted even after an extended period of observation. Densitometric measurements showed that the cytoplasmic content of the infected erythrocyte did not diffuse out as parasites were released, but was gradually lost thereafter. This would indicate that the release of merozoites from infected erythrocytes is not mediated by an explosive event.

Animals↗
PubMed2006

A novel X-linked recessive mental retardation syndrome comprising macrocephaly and ciliary dysfunction is allelic to oral-facial-digital type I syndrome.

We report on a large family in which a novel X-linked recessive mental retardation (XLMR) syndrome comprising macrocephaly and ciliary dysfunction co-segregates with a frameshift mutation in the OFD1 gene. Mutations of OFD1 have been associated with oral-facial-digital type 1 syndrome (OFD1S) that is characterized by X-chromosomal dominant inheritance and lethality in males. In contrast, the carrier females of our family were clinically inconspicuous, and the affected males suffered from severe mental retardation, recurrent respiratory tract infections and macrocephaly. All but one of the affected males died from respiratory problems in infancy; and impaired ciliary motility was confirmed in the index patient by high-speed video microscopy examination of nasal epithelium. This family broadens the phenotypic spectrum of OFD1 mutations in an unexpected way and sheds light on the complexity of the underlying disease mechanisms.

Alleles↗
PubMed2005

Three-dimensional registration of magnetic resonance image data to histological sections with model-based evaluation.

We developed a three-dimensional (3D) registration method to align medical scanner data with histological sections. After acquiring 3D medical scanner images, we sliced and photographed the tissue using, a custom apparatus, to obtain a volume of tissue section images. Histological samples from the sections were digitized using a video microscopy system. We aligned the histology and medical images to the reference tissue images using our 3D registration method. We applied the method to correlate in vivo magnetic resonance (MR) and histological measurements for radio-frequency thermal ablation lesions in rabbit thighs. For registration evaluation, we used an ellipsoid model to describe the lesion surfaces. The model surface closely fit the inner (M1) and outer (M2) boundaries of the hyperintense region in MR lesion images, and the boundary of necrosis (H1) in registered histology images. We used the distance between the model surfaces to indicate the 3D registration error. For four experiments, we measured a registration accuracy of 0.96+/- 0.13 mm (mean+/-SD) from the absolute distance between the M2 and H1 model surfaces, which compares favorably to the 0.70 mm in-plane MR voxel dimension. This suggests that our registration method provides sufficient spatial correspondence to correlate 3D medical scanner and histology data.

Anatomy, Cross-Sectional↗