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PubMed1999

Incorporation of functional status into dose-volume analysis.

The dose-volume histogram (DVH) has gained wide acceptance as a mechanism for reducing the voluminous data of a three-dimensional dose distribution into a two-dimensional graph. These graphs are often converted to a single figure of merit. This data reduction technique is used both for clinical treatment plan evaluation and as part of proposed systems for estimating control and complication probabilities. It has long been recognized that a major shortcoming of the DVH as an analysis tool is that all spatial information is discarded. A subtler problem, which is addressed in this work, is that the DVH also implies homogeneity of biological consequence of irradiation in what may be a functionally heterogeneous volume of tissue. An extension to the DVH, the functional dose-volume histogram, or dose-function histogram (DFH), is proposed, that explicitly includes quantitative three-dimensional functional information. The concept is illustrated by the use of SPECT imaging to assess the functional status of irradiated lung.

Humans↗
PubMed2001

Noise reduction in electron tomographic reconstructions using nonlinear anisotropic diffusion.

Electron tomography is a powerful technique capable of giving unique insights into the three-dimensional structural organization of pleomorphic biological objects. However, visualization and interpretation of the resulting volumetric data are hampered by an extremely low signal-to-noise ratio, especially when ice-embedded biological specimens are investigated. Usually, isosurface representation or volume rendering of such data is hindered without any further signal enhancement. We propose a novel technique for noise reduction based on nonlinear anisotropic diffusion. The approach combines efficient noise reduction with excellent signal preservation and is clearly superior to conventional methods (e.g., low-pass and median filtering) and invariant wavelet transform filtering. The gain in the signal-to-noise ratio is verified and demonstrated by means of Fourier shell correlation. Improved visualization performance after processing the 3D images is demonstrated with two examples, tomographic reconstructions of chromatin and of a mitochondrion. Parameter settings and discretization stencils are presented in detail.

Anisotropy↗
PubMed1996

Three-dimensional structure of nucleotide-bearing crossbridges in situ: oblique section reconstruction of insect flight muscle in AMPPNP at 23 degrees C.

We have explored the three-dimensional structure of myosin crossbridges in situ in order to define the structural changes that occur when nucleotide binds to the myosin motor. When AMPPNP binds to rigor insect flight muscle, each half sarcomere lengthens by approximately 2.0 nm and tension is reduced by approximately 70% without a reduction in stiffness, suggesting partial reversal of the power stroke. We have obtained averaged oblique section three-dimensional reconstructions of mechanically monitored insect flight muscle in AMPPNP that permit simultaneous examination of all myosin crossbridges within the unit cell and direct comparison of calculated transforms with X-ray diagrams of the native fibers. Transforms calculated from the oblique section reconstruction of AMPPNP insect flight muscle at 23 degrees C show good agreement with native X-ray diagrams, suggesting that the average crossbridge forms in the reconstruction reflect the native structure. In contrast to the rigor lead and rear crossbridges in the double chevrons, the averaged reconstruction of AMPPNP fibers show only one crossbridge class, in the position of the rigor lead bridge. The portion of the crossbridge close to the thick filament appears broader than in rigor, and shows a small 0.5 to 1.0 nm M-ward shift of the regulatory domain region of myosin. In transverse view, AMPPNP "lead" crossbridges are less azimuthally bent than rigor. Fitting the atomic model of actomyosin subfragment 1 to the averaged crossbridges shows that the detectable differences between rigor bridges and between rigor and AMPPNP bridges occur in the alignment and angles of the regulatory domains and suggests that rear bridges are more strained than lead crossbridges. The apparent absence of rear bridges in AMPPNP in averaged reconstructions indicates detachment of a number of force-bearing bridges, which conflicts with the maintained stiffness of the fibers used for the reconstruction. This conflict may be explained if rigor rear bridges become distributed irregularly over more actin sites in AMPPNP, so that their average density is too low to appear in the averaged reconstructions. The reconstructions indicate that in insect flight muscle the response of in situ rigor crossbridges to AMPPNP binding is not uniform. Lead bridges persist but have altered structure in the light chain domain, whereas rear bridges detach and possibly redistribute. Shape changes in attached myosin heads within the myofibrillar lattice are in the appropriate direction and of the appropriate magnitude needed to explain the sarcomere lengthening. This could be a direct response to nucleotide binding, a passive response to rear bridge detachment, or a combination of both.

Adenosine Triphosphate↗
PubMed1998

Transoral joint release of the dislocated atlantoaxial joints combined with posterior reduction and fusion for a late infantile atlantoaxial rotatory fixation. A case report.

STUDY DESIGN: A case of a late infantile atlantoaxial rotatory fixation is reported for which transoral anterior release was performed. OBJECTIVES: To report a patient who underwent transoral anterior release of the dislocated atlantoaxial joint for a case of late infantile atlantoaxial rotatory fixation and quadriparesis. SUMMARY OF BACKGROUND DATA: Infantile atlantoaxial rotatory fixation is diagnosed easily by using recently developed imaging techniques such as computed tomography, magnetic resonance imaging, and three-dimensional computed tomography. Nevertheless, patients in whom the condition has been overlooked still are encountered, and the reduction in these patients becomes impossible by traction or by simple posterior open reduction. Few reports on the management of type II-IV chronic atlantoaxial rotatory fixation in which an anterior surgery was performed exist in the literature, and no report exists in which atlantoaxial joint release on the both sides was attained. METHODS: A 9-year-old girl had a type III atlantoaxial rotatory fixation and quadriparesis. She received direct skull traction and repeated manual reduction while she was awake or under general anesthesia. Neither reduction nor movement was obtained, according to the radiographs. Therefore, it was necessary to perform open reduction posteriorly and transorally to release the fixed and contracted joints between C1 and C2. RESULTS: After the anterior release of the joints, there was an inherent force preventing a complete rotational reduction. However, after a successful posterior reduction and fusion, and for more than 4 years after surgery, neither rotatory displacement nor neurologic deterioration was noted. CONCLUSIONS: The authors suggest that careful transoral anterior release of the atlantoaxial joint permits successful reduction in a case of chronic fixed atlantoaxial rotatory fixation combined with cord compression.

Atlanto-Axial Joint↗
PubMed2004

Three-dimensional load measurements in an external fixator.

On the basis of a six-degree-of-freedom adjustable fracture reduction hexapod external fixator, a system which can be used for measuring axial and shear forces as well as torsion and bending moments in the fixator in vivo was developed. In a pilot study on 9 patients (7 fresh fractures and 2 osteotomies of the tibia), the load in the fixator during the healing process was measured after 2, 4, 8 and 12 weeks and at fixator removal. The measured values enabled both the type of fracture to be determined as well as the monitoring of the healing process. In well-reduced type A3 fractures small axial (direction of the bone axis) forces were found in the fixator. A2, B2 and C3 fractures showed distinct axial forces, which decreased during the healing process, according to an increasing load transfer over the bone. Bending moments in the fixator showed good correspondence with the clinical healing process, except in the case of a C3 fracture. A combination of bending moment and axial force proved to be particularly suitable to assess fracture healing. In transverse fractures, the well-known resorption phenomenon of bone in the fracture gap at approximately 4 weeks was detected by the system. Compared with other external fixator load measurements in vivo, the hexapod offers the advantage of being able to measure all forces and moments in the fixator separately and with a relatively simple mechanical arrangement. In our opinion, it will be possible to control fracture healing using this system, thereby minimizing radiation exposure from radiographs. Furthermore, the measurement system is a step towards the development of external fixator systems that enable automatic adjustments of the callus mechanical situation ("automatic dynamization") and inform the patients about the optimal weight bearing of their extremity ("intelligent fixator").

Equipment Design↗
PubMed2004

Detection of antibody-mediated reduction of annexin A5 anticoagulant activity in plasmas of patients with the antiphospholipid syndrome.

Annexin A5 (A5) forms 2-dimensional crystals over phospholipid bilayers, blocking their availability for coagulation reactions. Recently, human antiphospholipid (aPL) monoclonal antibodies (mAbs) have been demonstrated by atomic force microscopy (AFM) to disrupt this crystallization and accelerate coagulation. We therefore performed a study with small, well-defined groups of patients to investigate whether these effects on A5 binding and activity are also detectable in plasmas from patients with the aPL syndrome. A5 binding to phospholipid was significantly reduced by plasmas of patients with the aPL syndrome and thromboembolism compared with healthy controls (mean +/- SD, 26.7 +/- 4.3 ng/well [n = 25] vs 30.5 +/- 3.1 ng/well [n = 20], P < .01) and the non-aPL thromboembolism group (29.9 +/- 3.2 ng/well [n = 15], P < .05). A5 anticoagulant activity was reduced by plasmas of patients with aPL syndrome and thromboembolism compared with aPL antibodies without thrombosis (182 +/- 31% [n = 25] vs 210 +/- 35% [n = 26], P < .01), non-aPL thromboembolism (229 +/- 16% [n = 15], P < .001), and healthy controls (231 +/- 14% [n = 30], P < .001). In conclusion, in accordance with recent AFM data with monoclonal human aPL antibodies, plasmas from patients with aPL antibodies with thromboembolism reduce both A5 binding to phospholipid and A5 anticoagulant activity. This "annexin A5 resistance" identifies a novel mechanism for thrombosis in the aPL syndrome.

Annexin A5↗
PubMed2006

Evidence of two-dimensional superconductivity in the single crystalline nanohybrid of organic-bismuth cuprate.

A coordination compound of HgI(2)(pyridine)(2) can be successfully intercalated into a single crystalline Bi(2)Sr(2)CaCu(2)O(y) high-T(c) superconductor through an interlayer complexation reaction between pyridine molecules and bismuth cuprate pre-intercalated with mercuric iodide. X-ray diffraction and X-ray absorption spectroscopic results clearly demonstrate that the single crystalline nature of the pristine bismuth cuprate remains unchanged even after the intercalation of organic complex as well as those of iodine and mercuric iodide. According to the angle-dependent dc magnetization measurements, the intercalation of bulky organic molecules completely blocks superconductive currents along the c-axis, whereas a superconducting transition along the in-plane direction still occurs in the organic intercalate. In the case of the iodine or mercuric iodide intercalates with smaller lattice expansions, an out-of-plane diamagnetic transition is not wholly quenched but significantly depressed by the intercalation, confirming the reduction of interlayer interaction. The present finding can provide straightforward evidence of the two-dimensionality of high temperature superconductivity in the present cuprate-based nanohybrid material.

Bismuth↗
PubMed2006

Differential protein expression in the metal-reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate.

Geobacter sulfurreducens, generally considered to be a strict anaerobe, is a predominant microbe in subsurface environments, where it utilizes available metals as electron acceptors. To better understand the metabolic processes involved in the metal-reduction capability of this microbe, the proteins expressed by cells grown anaerobically with either fumarate or ferric citrate as electron acceptor were compared. Proteins were separated by 2-DE under denaturing or nondenaturing conditions, and proteins varying in abundance with a high level of statistical significance (p<0.0001) were identified by peptide mass analysis. Denaturing 2-DE revealed significant differences in the relative abundance of the membrane proteins OmpA and peptidoglycan-associated lipoprotein, several metabolic enzymes, and, in addition, superoxide dismutase and rubredoxin oxidoreductase. Nondenaturing 2-DE revealed elevated catalase in cells grown with ferric citrate. These results suggest that, in addition to adjustments in membrane transport and specific metabolic pathways in response to these two different electron acceptors, distinct differences exist in the oxidative environment within the cell when fumarate or soluble ferric citrate is provided as electron acceptor. Although an anaerobe, G. sulfurreducens appears to have alternate mechanisms for dealing with reactive oxygen species in response to increased intracellular soluble iron.

Anaerobiosis↗
PubMed1997

Optimal one- and two-dimensional filtering of transient-evoked otoacoustic emissions.

In the clinical use of evoked otoacoustic emissions the identification of the cochlear response and the reduction of the duration of the recording session are of great concern, especially if the recorded responses are to be used in hearing screening tasks. The aim of this paper is two-fold: to examine the potential and limits of optimal band-pass filtering to reduce the noise and increase identification of the cochlear response, and to introduce a technique of two-dimensional processing for reducing the acquisition time of TEOAEs. Band-pass filtering must guard against the loss of significant frequency components of the response; that is, the signals have to be filtered only when the filter bandwidth meets given conditions. As to test duration, preliminary results clearly indicate that two-dimensional filtering can substantially reduce the acquisition time, with only negligible losses in the basic response features, when a set of responses recorded at different stimulus levels is filtered.

Acoustic Stimulation↗
PubMed1999

Age-related reduction in 3-D visual motion priming.

In 3 experiments, younger and older adults judged the perceived motion of three-dimensional (3-D) figures that rotated in depth either unambiguously or ambiguously. Both groups were found to be equivalent in judging the direction of single rotations of the simulated 3-D objects (Experiment 1). In Experiments 2 and 3, a single unambiguous rotation (prime) was followed 0-3200 ms later by an ambiguous rotation (target). Motion priming was indicated by the disambiguation of the second rotation by the first rotation. 3-D motion priming was initially found to be similar in young and old, but it rapidly reduced in the older participants compared to the younger ones. Using a nonluminance depth cue--occlusion--to induce 3-D motion, diminished contrast sensitivity in the elderly was ruled out as a cause of the reduced priming. The results show that 3-D motion priming exhibits robust age-related decline. An age-related decrease in temporal persistence may account for the reduction in 3-D motion priming in older adults.

Adult↗
PubMed1983

The presence of intermolecular disulfide cross-links in type III collagen.

Bovine and lathyritic rat type III collagen preparations were analyzed for the presence and in vitro formation of intermolecular disulfide cross-links. Type III collagen from fetal bovine skin was extracted with the aid of pepsin and purified by differential salt precipitation, guanidine denaturation, and renaturation. Nearly all of the type III collagen was present as reduction-sensitive gamma-components and higher molecular weight aggregates. After cleavage with CNBr, the peptides were analyzed by two-dimensional mapping. The presence of intermolecular disulfide bonds was demonstrated by the existence of a hexamer of the COOH-terminal CNBr peptide, CB9B. This cross-linked peptide was completely converted to the CB9B monomer by reduction. Type III collagen from the skins of beta-aminoproprionitrile-treated rats was used to test for the in vitro formation of intermolecular disulfide cross-links. This was prepared by salt extraction, differential salt precipitation, and pepsin treatment. Sodium dodecyl sulfate-gel electrophoresis of this partially purified type III collagen before reconstitution into fibers detected primarily gamma-chains. After reconstitution into fibers, the majority of the material was present as higher molecular weight aggregates. Upon reduction, these aggregates generated predominantly alpha-chains. These data demonstrate the existence of intermolecular disulfide bonds in native type III collagen and their formation during in vitro fibrillogenesis.

Animals↗
PubMed2005

Brain 3D-SSP SPECT analysis in dementia with Lewy bodies, Parkinson's disease with and without dementia, and Alzheimer's disease.

OBJECTIVES: Cerebral blood flow was compared among patients with dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), Parkinson's disease without dementia (PD), and Alzheimer's disease (AD) using three-dimensional stereotactic surface projection (3D-SSP) analysis. PURPOSE: We attempt to clarify the difference of reduction pattern on SPECT among patients having DLB, PDD, PD, AD. PATIENTS AND METHODS: Six patients with DLB, 7 patients with PDD who were matched with the DLB patients for age, unified Parkinson's disease rating scale-III (UPDRS-III) score, and degree of cognitive function disorders, 21 patients with PD who were matched with the DLB patients for age, UPDRS-III score, 12 patients with AD who were matched with the DLB patients for age and degree of cognitive function disorders, and 12 control subjects. All patients were examined by N-isopropyl-p[123I] iodoamphetamine single photon emission computed tomography (123I-IMP SPECT), and obtained images were analyzed with 3D-SSP using an image-analysis software, iSSP ver. 3.5. RESULTS: Although DLB and PDD showed similar cerebral perfusion reduction pattern at the lateral parietal association and lateral temporal association and precuneus on SPECT by the pixel-by-pixel comparison, greater perfusion reduction was observed in DLB than in PDD. Cerebral perfusion was decreased at the occipital lobe of the DLB patients compared with the AD patients. CONCLUSIONS: The regional pattern of blood flow reduction in the brain was found to be different among DLB, PD, and AD. Greater blood flow reduction was observed in DLB, although DLB and PDD showed similar reduction pattern. These regional differences were considered to suggest different and disease-specific combinations of underlying pathological and neurochemical processes.

Aged↗
PubMed1998

Impact of ischemia-reperfusion injury on dimensional changes of hepatic microvessels.

Dimensional alteration of hepatic microvessels was demonstrated during reperfusion after normothermic hepatic ischemia. Using a specially designed cover glass, it was possible to relocate selected sites of observation and microvessels repeatedly throughout the whole reperfusion time. Twenty minutes of hepatic ischemia resulted in a decrease of sinusoidal diameter (mean +/- SEM; 10.0 +/- 0.3 microns at baseline, 8.2 +/- 0.2 microns after ischemia) and diameter of postsinusoidal venules (26.4 +/- 1.2 at baseline, 23.0 +/- 1.0 after ischemia). In the control group (no ischemia induced) no changes of these parameters were observed. Thus, the reduction of hepatic microvascular cross section was present during the early phase of reperfusion. Hepatic dysfunction was characterized by increased serum activity of liver enzymes and reduction of bile flow in the ischemia-exposed animals. It has been suggested that postischemic dimensional microvascular changes are involved in postischemic liver dysfunction.

Animals↗
PubMed1998

Beneficial effects of 1-year captopril therapy in children with chronic aortic regurgitation who have no symptoms.

OBJECTIVE: This prospective study was performed to assess the effects of 1 year of angiotensin-converting enzyme inhibition with captopril in 20 children (mean age 14.3+/-2.3 years) with asymptomatic chronic aortic regurgitation. METHODS AND RESULTS: At 12 months patients receiving captopril had a significant reduction in left ventricular end-diastolic and end-systolic dimensions (57+/-9.3 vs 51+/-9.5 mm, p < 0.001; 35.4+/-6.1 vs 32+/-6.8 mm, p < 0.001), end-diastolic and end-systolic volume indexes (111+/-36 vs 94+/-29 ml/m2, p < 0.001; 35+/-13 vs 30+/-12 ml/m2, p < 0.001, respectively), and mass index (138+/-37 vs 109+/-32 gm/m2, p < 0.0001) determined by two-dimensional echocardiography. Meridian (p < 0.01) and circumferential (p < 0.0001) wall stresses also decreased significantly with therapy. Significant reduction (27.8%, p < 0.0001) was achieved in regurgitant fraction with captopril. CONCLUSIONS: These data show that the long-term therapy with angiotensin-converting enzyme inhibitors is able to reverse left ventricular dilation and hypertrophy and suggest that such therapy has the potential to favorably influence the natural history of the disease in children.

Administration, Oral↗
PubMed2005

A cross-study meta-analysis and three-dimensional comparison of cell counting in the anterior cingulate cortex of schizophrenic and bipolar brain.

Using a two-dimensional cell counting approach, a 1991 study in the anterior cingulate cortex (ACCx) detected a reduction in the density of nonpyramidal neurons in layers II-VI of schizophrenic subjects. Schizophrenics without superimposed mood disturbances showed a 16% decrease in layer II, while schizoaffectives showed a 30% decrease, suggesting that a decreased density of nonpyramidal neurons in layer II of ACCx might vary more strongly with affective disorder than with schizophrenia. Two follow-up studies from this laboratory, one a replication of that reported in 1991 and the other an analysis of tyrosine hydroxylase immunoreactive fibers, were undertaken in ACCx of normal controls and schizophrenics. These three data sets have been combined and a meta-analysis of the density of pyramidal, nonpyramidal and glial cells was performed to explore whether changes in the density of interneurons in ACCx may be a reliable finding in the major psychoses. Not all groups have reported this finding, but several had employed a different cell counting technique (i.e. three dimensional optical dissector), which could help to explain the discrepant findings in schizophrenia and affective disorder. The data from each of three different studies (now designated as studies A, B and C, respectively) have been internally normalized, combined into a single dataset and analyzed using nonparametric statistics. Tissue blocks from a subset of cases in study B (six controls, six schizophrenics and six bipolars) were embedded in celloidin and counted using an "unbiased" three dimensional counting method (study D). The data from studies A and B indicate that the density of nonpyramidal neurons in layer II of ACCx in the schizoaffective and bipolar samples was significantly decreased. In the schizophrenics, the nonpyramidal neurons were also decreased, but only by 15%. All three groups also showed a decrease of pyramidal neurons in layers IV, V and VI, but this difference was significant only in layer IV of the schizophrenics. When data from study C were added, the differences in pyramidal and nonpyramidal neurons were less striking. For study D, the pattern of findings are strikingly similar to those obtained in studies A, B and C, indicating that both 2D and 3D cell counting methodologies are capable of detecting the same differences. Taken together, these results indicate that the earlier finding of a decreased density of nonpyramidal neurons in ACCx of schizophrenics is consistent across non-overlapping subjects and/or methods in four separate studies, and is more pronounced in schizoaffective and bipolar subjects than in schizophrenics without superimposed mood disturbance.

Bipolar Disorder↗
PubMed2005

Data reduction in headspace analysis of blood and urine samples for robust bacterial identification.

This paper demonstrates the application of chemical headspace analysis to the problem of classifying the presence of bacteria in biomedical samples by using computational tools. Blood and urine samples of disparate forms were analysed using a Cyrano Sciences C320 electronic nose together with an Agilent 4440 Chemosensor. The high dimensional data sets resulting from these devices present computational problems for parameter estimation of discriminant models. A variety of data reduction and pattern recognition techniques were employed in an attempt to optimise the classification process. A 100% successful classification rate for the blood data from the Agilent 4440 was achieved by combining a Sammon mapping with a radial basis function neural network. In comparison a successful classification rate of 80% was achieved for the urine data from the C320 which were analysed using a novel nonlinear time series model.

Bacteremia↗
PubMed2000

Oxidative modification of creatine kinase BB in Alzheimer's disease brain.

Creatine kinase (CK) BB, a member of the CK gene family, is a predominantly cytosolic CK isoform in the brain and plays a key role in regulation of the ATP level in neural cells. CK BB levels are reduced in brain regions affected by neurodegeneration in Alzheimer's disease (AD), Pick's disease, and Lewy body dementia, and this reduction is not a result of decreased mRNA levels. This study demonstrates that posttranslational modification of CK BB plays a role in the decrease of CK activity in AD brain. The specific CK BB activity and protein carbonyl content were determined in brain extracts of six AD and six age-matched control subjects. CK BB activity per microgram of immunoreactive CK BB protein was lower in AD than in control brain extracts, indicating the presence of inactive CK BB molecules. The analysis of specific protein carbonyl levels in CK BB, performed by two-dimensional fingerprinting of oxidatively modified proteins, identified CK BB as one of the targets of protein oxidation in the AD brain. The increase of protein carbonyl content in CK BB provides evidence that oxidative posttranslational modification of CK BB plays a role in the loss of CK BB activity in AD.

Aged↗
PubMed1996

Three-dimensional regional dynamics of the normal mitral anulus during left ventricular ejection.

The mitral anulus is a dynamic structure that undergoes alterations in size and shape throughout the cardiac cycle, contracting during systole. Numerous reports have shown this systolic orifice reduction to be due chiefly to posterior annular contraction, whereas the anterior perimeter was unchanged. Segmental motion of the mitral anulus from true in vivo three-dimensional data, however, has not been described. We used radiopaque markers and simultaneous biplane videofluoroscopy to measure the lengths of mitral anular segments in seven closed-chest, sedated dogs. Eight markers were placed equidistant from each other around the mitral anulus, As viewed from the left atrium, segment 1 began at the posteromedial commissure, and the remaining segments were numbered sequentially clockwise around the anulus (that is, the posterior mitral anulus encompassed segments 1 to 4 and the anterior anulus encompassed segments 5 to 8). Marker image coordinates obtained from two orthogonal views 7 to 12 days after implantation were merged to construct three-dimensional marker coordinates at end-diastole and end-systole. From end-diastole to end-systole, mean annular area decreased by 11% +/- 8% (5.5 +/- 0.9 cm2 to 4.9 +/- 0.8 cm2, p = 0.005) and perimeter by 5% +/- 4% (8.8 +/- 0.7 cm to 8.3 +/- 0.7 cm, p < 0.01). Mitral annular segmental percent systolic shortening (negative values indicate lengthening) were as follows (mean +/- standard deviation): segment 1, 7% +/- 9%; segment 2, 8% +/- 10%; segment 3, 16% +/- 6%; segment 4, 10% +/- 7%; segment 5, -4% +/- 5%, segment 6, -7% +/-7%; segment 7, 3% +/- 2%; and segment 8, 6% +/- 5%. With the exception of segment 1, all posterior (2 to 4) and two anterior (7 and 8) mitral annular segments contracted significantly (p < or = vs zero, paired t test). Two anterior annular segments (5 and 6, regions overlapping aortic-mitral continuity), however, unexpectedly lengthened during left ventricular systole. We conclude that the anterior mitral anulus may be a much more dynamic component of the mitral apparatus that previously thought. Such heterogeneous dynamic annular motion should be taken into account when various mitral valve reparative techniques are being designed.

Animals↗