Computer-assisted Analysis System Research Articles

A new chamber technique for intravital microscopic observations in the different soft tissue layers of mouse hindleg.

A newly developed observation chamber has been designed for comfortable limb immobilization during intravital microscopic analysis, which permits direct, repeated, long-lasting observations of the microcirculation in the various hindleg soft tissues. Experiments were performed under inhalation isoflurane/nitrous oxide anesthesia. Intravenously injected fluorescein isothiocyanate (FITC)-dextran (M, 150,000) and Rhodamine 6G (Sigma, St. Louis, MO) allowed for visualization of both microcirculatory phenomena in arterioles, capillaries, and venules and macrocirculatory structures as superficial saphenous artery and vein. Skin microcirculation analysis was performed from the epidermal side (group A, n = 7), whereas observation of deeper situated tissues was performed after oval skin excision on the medial surface of the tibial area (group B, n = 7). FITC-dextran (M, 150,000; group C, n = 8) injected into the foot pad permitted visualization of venous, arterial, and accompanying lymphatic vessels. With the aid of a computer-assisted microcirculation analysis system, functional capillary density, vessel diameter, edema formation, and leukocyte-endothelial cell interactions were evaluated. The ratio of rolling leukocytes, given as percentage of all leukocytes passing the vessel segment during a 30-second observation interval, and the number of sticking leukocytes per square millimeter of endothelial surface were determined. This new model allows the analysis of the complex in vivo changes of macro- and microcirculatory parameters in the different (venous, arterial, lymphatic) vessels of the covering tissues (skin and muscle) of the mouse hindleg. The potential applications of this technique include the study of mechanical trauma, ischemia-reperfusion injury, and tissue compression mimicking both acute and prolonged venous stasis on both the microcirculatory and macrocirculatory levels in the different tissue compartments.

The internal phosphodiesterase RegA is essential for the suppression of lateral pseudopods during Dictyostelium chemotaxis.

Dictyostelium strains in which the gene encoding the cytoplasmic cAMP phosphodiesterase RegA is inactivated form small aggregates. This defect was corrected by introducing copies of the wild-type regA gene, indicating that the defect was solely the consequence of the loss of the phosphodiesterase. Using a computer-assisted motion analysis system, regA(-) mutant cells were found to show little sense of direction during aggregation. When labeled wild-type cells were followed in a field of aggregating regA(-) cells, they also failed to move in an orderly direction, indicating that signaling was impaired in mutant cell cultures. However, when labeled regA(-) cells were followed in a field of aggregating wild-type cells, they again failed to move in an orderly manner, primarily in the deduced fronts of waves, indicating that the chemotactic response was also impaired. Since wild-type cells must assess both the increasing spatial gradient and the increasing temporal gradient of cAMP in the front of a natural wave, the behavior of regA(-) cells was motion analyzed first in simulated temporal waves in the absence of spatial gradients and then was analyzed in spatial gradients in the absence of temporal waves. Our results demonstrate that RegA is involved neither in assessing the direction of a spatial gradient of cAMP nor in distinguishing between increasing and decreasing temporal gradients of cAMP. However, RegA is essential for specifically suppressing lateral pseudopod formation during the response to an increasing temporal gradient of cAMP, a necessary component of natural chemotaxis. We discuss the possibility that RegA functions in a network that regulates myosin phosphorylation by controlling internal cAMP levels, and, in support of that hypothesis, we demonstrate that myosin II does not localize in a normal manner to the cortex of regA(-) cells in an increasing temporal gradient of cAMP.

Effects of selenium deficiency on the rat myocardial protein pattern-- investigation by two-dimensional gel electrophoresis.

Dietary selenium deficiency represents an etiological factor in "Keshan disease", a distinct form of an endemic cardiomyopathy. The biochemical effects of selenium depletion in the myocardium are, however, not yet known. Therefore, we investigated the changes in the myocardial protein pattern in rats after long-term selenium deficiency. The myocardial proteins were analyzed in samples from five selenium-depleted rats (Se-deficient group) and five rats supplied with adequate amounts of the element (Se-adequate group). Isoelectric focusing (IEF) with carrier ampholytes on large 2-DE gels was used for the separation of proteins in the first dimension and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for the second dimension. The protein patterns were evaluated by means of a computer-assisted gel analysis system. The biochemical identification of the proteins of interest was achieved by matrix-assisted laser desorption/ionization mass spectrometry (MALDI) or immunoblotting. On average, 588 +/- 68 protein spots were found on the gels. No significant difference in spot numbers existed between the groups. A pattern of 270 spots with identical positions was found on every gel; 247 of these spots were not saturated and used for quantitative comparison. Thirty-five, i.e., 14 %, differed significantly in their relative intensity in the two groups. Twenty-eight protein spots were decreased in the Se-deficient group and seven were increased. Sarcomeric creatine kinase M chain, alpha-myosin heavy chain (alpha-MHC) and myosin light chain 1 and 2 (MLC 1 and 2) were largely decreased in Se-deficiency. Three protein spots were increased by more than twofold or appeared only in the Se-deficient group. A mitochondrial creatine kinase was identified in this group. The results suggest that selenium deficiency affects myocardial energy metabolism and contractile proteins. These changes probably reflect non-specific alterations in heart failure.

Utilization of a Computer-Assisted Sperm Motion Analysis System to Examine Effects of Dinoseb on Rat Sperm.

The computer-assisted sperm motion analysis (CASA) system has been used as one of the useful means for reproductive toxicity studies in male animals. Since various parameters of sperm motility are measured by the CASA system, we investigated the effects of a herbicide dinoseb, a testicular toxicant, and which parameter was the most appropriate for detecting changes. Crj:CD(SD)IGS mature male rats were administered dinoseb at a dose of 0 (corn oil), 5 or 7.5 mg/kg for 3 consecutive days, and were necropsied for cauda epididymal sperm analysis after a 12-day (Day15) or 19-day (Day 22) withdrawal period (Experiment I). No sperm motility parameters of dinoseb-treated rats were changed on Day 15, but on Day 22, the percentage of motile sperm (MOT) was significantly decreased in rats treated with dinoseb at 7.5 mg/kg. Other parameters, such as path velocity (VAP), curvilinear velocity (VCL), and amplitude of lateral head displacement (ALH) were significantly decreased as well. In Experiment II, no parameters of sperm motility showed any change in rats treated with dinoseb at 7.5 mg/kg three times per week when evaluated on Day 21. It was concluded that MOT, VAP, VCL, and ALH were more sensitive to dinoseb effects on sperm in the CASA system.

In situ Monitoring of the Cure Process of Fiberglass/Polyester Composites

The theoretical relationship between the extent of cure and the temperature obtained in thermoset polyester resins is introduced. The curing behavior of resins in the presence of reinforcing phases was also investigated using a computer-assisted thermal analysis system. The outcome of the study was that the relationship between the cure time and temperature readings on the specimen can be used to assess the extent of cure.

Computerized assessment of endometrial echogenicity: clues to the endometrial effects of premature progesterone elevation

Objective: To determine whether premature progesterone elevation affects the timing of hyperechogenic transformation of the endometrium during the early luteal phase of controlled ovarian hyperstimulation (COH) cycles. Design: Prospective analysis. Setting: Assisted Reproduction Unit, Hôpital Antoine Béclère, Clamart, France. Patient(s): Fifty-nine women undergoing 59 IVF-ET cycles. Intervention(s): Patients underwent COH with a GnRH agonist and hMG. Endometrial echogenicity was assessed on the days of hCG administration, oocyte retrieval, and ET. Results are expressed as the extent of submyometrial hyperechogenic area in relation to the total endometrial surface as determined by a computer-assisted analysis system. Patients were sorted according to whether their plasma progesterone level exceeded 0.9 ng/mL (n = 26) or not (n = 33) on the day of hCG administration. Main Outcome Measure(s): Endometrial echogenicity. Result(s): On the day of hCG administration, the degree of endometrial echogenicity was similar in both groups (41% vs. 40%), but after hCG administration, it increased significantly faster in the high progesterone group than in the low progesterone group (70% vs. 63% at oocyte retrieval and 90% vs. 79% at ET, respectively). Conclusion(s): End–follicular phase elevation in plasma progesterone (>0.9 ng/mL on the day of hCG administration) was associated with a faster increase in endometrial echogenicity during the early luteal phase of COH cycles. This observation is consistent with the hypothesis that premature progesterone elevation hastens the secretory transformation of the endometrium.

An intravital fluorescence microscopic study of hepatic microvascular and cellular derangements in developing cirrhosis in rats.

Quantitative data defining the relationship between the hepatic microcirculation and the development of liver pathological changes could provide a basis for a better understanding of fibrogenic processes, such as cirrhosis. Therefore, we established the technique of intravital fluorescence microscopy and computer-assisted microcirculation analysis systems in developing cirrhosis in rats with the aim of quantitatively assessing the association of hepatic microvascular morphology with its disordered acinar architecture, and nonparenchymal cell transformation with collagen deposition, parenchymal cell loss, and liver dysfunction. In animals chronically exposed to carbon tetrachloride (CCl4), the most significant microvascular changes progressively observed in vivo were the concomitant appearance of 1) sinusoid-free space around dilated postsinusoidal venules with 2) substituting occurrence of yellow-green autofluorescent collagen deposition, 3) reduction in sinusoidal density, but 4) increase of vascular lumen caused by the formation of shunting vessels bypassing the sinusoids. Present on-line analysis further indicated the local coincidence of changed spatial distribution of Ito cells (accumulation of vitamin A ultraviolet autofluorescence in zone 3) with fibrotic autofluorescent septa, causing significant collapse of parenchymal tissue (hepatocellular bis-benzamide fluorescence) and diminution of hepatocellular excretory function (bile flow). Regression analysis revealed strong correlations between loss of parenchymal tissue and both collagen deposition and sinusoidal rarefication, as well as between sinusoidal rarefication and collagen deposition. Thus, sequential in vivo analysis presented herein provides the new information on the concomitant onset of cellular, fibrotic, and microvascular changes in developing fibrosis/cirrhosis, excluding that distinct cellular or fibrotic alterations are a prerequisite for the manifestation of microcirculatory and vascular derangements or vice versa.

Validity of radiographic measurement of interproximal bone loss

The aim of the present study was to compare radiographic assessment of interproximal bone loss using a loupe with a 0.1 mm calibrated grid and a computer-assisted analysis system (LMSRT). In 35 patients suffering from untreated advanced periodontal disease, 62 standardized radiographs were taken presurgically. The horizontal and vertical angulation difference of the central beam from the orthoradial projection was calculated for each radiograph. At the time of surgery, for 115 interproximal defects, the distances from the cementoenamel junction (CEJ) to alveolar crest (AC), and CEJ to bottom of the bony defect (BD) were measured. In all radiographs, the linear distances CEJ to AC, and CEJ to BD were assessed using a loupe and LMSRT. Comparison between radiographic and intrasurgical assessments was performed using paired t-tests. A stepwise multiple linear regression analysis was used to evaluate factors that influence the discrepancy between radiographic and intrasurgical measurements. Both analyzing techniques underestimated interproximal bone loss as compared with intrasurgical measurements (CEJ-AC: loupe: 0.86 ± 1.84 mm [ p < 0.001]; LMSRT: 0.58 ± 1.86 mm [ p < 0.005]; CEJ-BD: loupe: 1.22 ± 2.33 mm [ p < 0.001]; LMSRT: 0.80 ± 2.09 mm [ p < 0.001]). LMSRT underestimated interproximal bone loss significantly less than the loupe ( p < 0.001). The difference between LMSRT and intrasurgical assessments was modulated by the factors of vertical and horizontal angulation difference and defect depth ( p < 0.1). Orthoradial projection reduced underestimation of radiographic assessment of bone loss. LMSRT underestimated interproximal bone loss to a lesser extent than conventional evaluation by loupe.

A novel model for the study of synovial microcirculation in the mouse knee joint in vivo.

A novel model for the investigation of the microcirculation in synovial tissue of the mouse knee joint is presented. The mouse knee joint was exposed on a specially designed plexiglass stage with a slight flexion. After partial resection of the skin, the patella tendon was cut transversally, which allowed for visualization of the "Hoffa's fatty body", an intraarticular fatty tissue containing synovial cells on the interior surface of the joint. An intravital fluorescence microscope was adjusted to observe the microcirculation of this intraarticular synovial tissue without opening of the joint capsula. For staining of the plasma, fluorescein isothiocyanate (FITC)-dextran was used, and for the staining of leukocytes rhodamine 6G was used. The tissue investigated presents with a high-density honeycomb-like capillary network, containing some postcapillary venules and a few arterioles. The following parameters were assessed off-line using a computer-assisted microcirculation analysis system: flow and diameter of arterioles and postcapillary venules, as well as functional capillary density. Moreover, leukocyte-endothelial cell interaction was quantified by counting the number of rolling cells and cells adhering to the endothelium in postcapillary venules. As an indication of endothelial leakage, macromolecular extravasation was also assessed. To validate the model, we investigated these parameters at three time points during an observation period of 60 min. There was no change in functional capillary density, nor in vessel diameter after 60 min of observation. Moreover, there was neither a change in the number of rolling cells, nor in the number of cells adhering to the endothelium nor in extravasation of FITC-dextran, thus indicating the stability of the preparation. The new model allows the quantitative analysis of the intraarticular microcirculation of the synovial fatty tissue in vivo. It provides insight into the dynamics of synovial microcirculation and leukocyte-endothelial cell interaction in acute or chronic joint inflammation.

Reliability and precision of a static clinical versus a dynamic laboratory method of measurement of the leg and foot on stable and unstable ankles

In the quest to justify current orthotic treatment protocols, there is a trend for clinical practitioners to invest in computer-assisted video gait analysis systems, and rely less on clinical measurement protocols. The aim of the study was to determine the extent to which an experienced clinician would benefit in obtaining precise and reliable measurements by replacing their inexpensive static measurement protocol with a computer-assisted video analysis system. Measures of 10 subjects, having both a functionally stable and unstable ankle, were obtained in the frontal plane. This was done statically using clinical protocol and dynamically using the Ariel Performance Analysis System (APAS). The static clinical and dynamic laboratory protocols were found to be comparable and of acceptable reliability (ICC > 0.810) and a minor mean improvement in precision (0.23°) was observed when using the laboratory protocol. It was, therefore, concluded that if the purpose of measurement is to obtain precise and reliable frontal plane data, then the static clinical protocol is as useful as the dynamic laboratory protocol.

Effects of strabismus surgery on corneal topography.

Changes in refraction follow surgery on the extraocular muscles. We examined corneal topography before and after medial or lateral rectus muscle recession using a computer-assisted topographic analysis system. A total of 36 patients (52 eyes) were examined. Measurements were taken 1 day before surgery and 1, 15, and 30 days after surgery. A significant change in astigmatic power was detected 1 day after surgery in the meridian of the recessed muscle, evidencing a localized flattening of the cornea. Induced astigmatism decreased over time. At 30 days following surgery, 6% of patients evidenced a residual change higher than 1 diopter (D); 12% evidenced a residual change higher than 0.5 D. The increase of astigmatic power recorded 1 day after surgery is higher for medial rectus muscle recession than for lateral rectus muscle recession. Corneal topography changes, located mainly in the meridian of the recessed muscle and the optical zone, are greatly reduced or gone within 1 month of surgery.

Quantitative analysis of Caenorhabditis elegans sperm motility and how it is affected by mutants spe11 and unc54

The sperm of Caenorhabditis elegans translocate in a fashion similar to sperm of Ascaris suum even though their pseudopods are longer, more plastic in shape, and form multiple expansion zones around their perimeter. Mutants in spe-11 form primary spermatocytes with a defective perinuclear region, but the resulting spermatozoa can still crawl and fertilize eggs. However, the resultant zygotes die due to the absence of sperm-supplied spe-11. Computer-assisted analysis of translocating spe-11 sperm reveals a novel defect in the dynamic morphology of their pseudopods. A similar analysis of the C. elegans mutant unc-54, which lacks the most abundant isoform of myosin II, reveals no defect in sperm motility, as expected, since C. elegans sperm have substituted the protein MSP for actin in the process of pseudopod expansion. These results reveal an unexpected defect in the dynamic morphology of pseudopods of spe-11 sperm. This defect, however, does not significantly affect crawling velocity, and it demonstrates how computer-assisted motion analysis systems can reveal subtle behavioral phenotypes in C. elegans mutant spermatozoa. Cell Motil. Cytoskeleton 37:98–110, 1997. © 1997 Wiley-Liss Inc.

Quantitative analysis ofCaenorhabditis elegans sperm motility and how it is affected by mutantsspe11 andunc54

The sperm of Caenorhabditis elegans translocate in a fashion similar to sperm of Ascaris suum even though their pseudopods are longer, more plastic in shape, and form multiple expansions zones around their perimeter. Mutants in spe-11 form primary spermatocytes with a defective perinuclear region, but the resulting spermatozoa can still crawl and fertilize eggs. However, the resultant zygotes die due to the absence of sperm-supplied spe-11. Computer-assisted analysis of translocating spe-11 sperm reveals a novel defect in the dynamic morphology of their pseudopods. A similar analysis of the C. elegans mutant unc-54, which lacks the most abundant isoform of myosin II, reveals no defect in sperm motility, as expected, since C. elegans sperm have substituted the protein MSP for actin in the process of pseudopod expansion. These results reveal an unexpected defect in the dynamic morphology of pseudopods of spe-11 sperm. This defect, however, does not significantly affect crawling velocity, and it demonstrates how computer-assisted motion analysis systems can reveal subtle behavioral phenotypes in C. elegans mutant spermatozoa.

Evaluation of computer-assisted semen analysis (CASA) with IDENT stain to determine sperm concentration.

This study was undertaken to compare a new fluorescent stain-based computer-assisted semen analysis (CASA) system (IDENT) for determining human sperm concentration to the manual hemacytometric method and to conventional CASA (CASA-CONV). Normal healthy semen donors as well as patients provided samples that were evaluated for sperm concentration with the CASA-IDENT method, the hemacytometer method, and CASA-CONV. Each field was examined visually to determine the sources of overcounting and undercounting for the two CASA methods. Four ranges of sperm concentration were examined: 0-10, > 10-30, > 30-100, and > 100 x 10(6)/ml. The main outcome measures were sperm concentration, debris counted as sperm, and missed sperm. Our results showed that significantly more debris was counted as sperm and more sperm were missed with CASA-CONV than CASA-IDENT. As the sperm density increased, so did the number of counting errors for the CASA-CONV system. The error rate was much greater using CASA-CONV (12.1 +/- 42.2%) than with CASA-IDENT (0.4 +/- 0.7%) when compared to hemacytometer counts (P = 0.068). We conclude that the CASA-IDENT method of sperm counting is highly accurate and less time-consuming when compared to the hemacytometer method. There are significant differences in the amount of debris counted as sperm and number of missed sperm between CASA-CONV and CASA-IDENT with varying sperm density. With both parameters, the counts are more accurate using the CASA-IDENT method.

Increased reactive oxygen species formation in semen of patients with spinal cord injury

To evaluate reactive oxygen species production of semen samples and Percoll-washed spermatozoa from men with spinal cord injuries and to determine if there is a relationship between this reactive oxygen species production and sperm motility.Semen samples from healthy volunteers and infertile patients were collected by masturbation.Semen samples from men with a spinal cord injury were obtained by electroejaculation or by masturbation after treatment with physostigmine.Motility was measured using the CellSoft computer-assisted analysis system (Cryo Resources Ltd., Montgomery, NY). Luminol-amplified chemiluminescence was used to measure reactive oxygen species production.Semen samples and Percoll-washed spermatozoa from men with a spinal cord injury produced reactive oxygen species at much higher frequency and levels than equivalent preparations from infertile men or healthy volunteers. There was an inverse relationship between the percentage of motility and reactive oxygen species production in Percoll-washed spermatozoa from men with a spinal cord injury.Semen samples and Percoll-washed spermatozoa from men with spinal cord injury produce high levels of reactive oxygen species that may be related to the low sperm motility and infertility observed in these men.

814-2 Responses of Internal Mammary Artery to Local Administration of Acetylcholine

Internal mammary arteries (IMA) are widely used for coronary artery bypass grafting, and being reported to have a much higher long-term patency rate than that of saphenous veins. Therefore, we hypothesized that the endothelial function of IMA is better preserved compared with that of coronary arteries. To evaluate the endothelial function of IMA, acetylcholine (ACh) was selectively injected into IMA and both coronary arteries in 7 male and 4 female patients (mean age; 61 ± 11 (SD) years) with atypical chest pain and normal coronary arteriograms. Angiography was repeated before and after the selective injection of various doses of ACh and 1 mg of isosorbide dinitrate (ISDN). Injection of ACh into coronary arteries provoked neither chest pain nor ST-segment shifts. The diameter of IMA and both coronary arteries was measured with a computer-assisted analysis system. Arterial pressures and heart rates remained unchanged despite the selective injection of ACh and ISDN. Diameters (mm) were: Control ACh ISDN 25/ μ g 50/ μ g 100/ μ g RCA 2.04 ± 0.49 1.87 ± 0.40 ** 1.62 ± 0.41 ** – 2.44 ± 0.63 ** LCA 2.06 ± 0.50 1.92 ± 0.50 * 1.80 ± 0.49 ** 1.69 ± 0.46 ** 2.37 ± 0.54 ** IMA 2.02 ± 0.53 2.22 ± 0.56 ** 2.36 ± 0.57 ** – 2.43 ± 0.50 ** * p &lt; 0.05 ** p &lt; 0.01 vs. control values by ANOVA The diameters of both coronary arteries were decreased by ACh in a dosedependent manner, whereas IMA showed a dose-dependent dilation with ACh. These findings indicate that the endothelial function of IMA is well preserved, because ACh-induced endothelium-derived relaxing factors could counteract the contraction of vascular smooth muscle cells induced by ACh.

Functional capillary density: an indicator of tissue perfusion?

Functional capillary density (FCD) is one of the parameters obtained by intravital microscopy using epi-illumination of the tissue surface or trans-illumination of thin tissue layers. FCD, defined as the length of red cell-perfused capillaries per observation area (cm-1), has been used as an indicator of the quality of tissue perfusion in various animal models. Quantitative analysis of FCD in randomly selected regions of the tissue is performed by means of a computer-assisted video analysis system which allows calculation of the length of RBC-perfused capillaries. Basically, two different mathematical approaches can be employed: the first approach is based on the addition of the distances between two neighboring points (pixels) on the video screen (Pythagorean principle). The second approach uses the superimposition of a grid system that allows estimation of the capillary length by counting the number of intersections between the capillaries and the grid lines (stereological approach). The immanent error has been calculated in our laboratory to be +/- 1% with the Pythagorean and +/- 5% with the stereological method. Beside these systematic errors of computerized measurement, the individual (user-dependent) errors occurring during recognition and redrawing of the capillaries on the video image with use of a digitizing tablet are in the range of +/- 10% (intraindividual) and +/- 70% (interindividual) for the recognition and +/- 3% (interindividual) for the redrawing procedure. Our studies indicate that the errors resulting from the use of a computer-assisted calculation (Pythagorean or stereological approach) or the user-assisted redrawing of the capillaries are negligible when compared to the errors made during recognition of the capillaries on the video screen. The methods are applied for assessment of FCD in two different microcirculation models of skin muscle and pancreas yielding highly reproducible, user-independent results under physiologic conditions and the pathophysiologic conditions of ischemia-reperfusion.

A Computer-assisted Plankton Analysis System for the Macintosh

CAPAS (Computer-assisted Plankton Analysis System), an application software developed for Macintosh computers, was designed for the analysis of taxonomic and size composition of zooplankton. We based CAPAS on the zooplankton analysis system of Mills and Confer (1986), but instead of using electronic calipers, CAPAS requires a digitizing surface for making one-dimensional plankter measurements. Advantages of CAPAS over Mills and Confer's system (1986) include (1) freedom from caliper-associated mechanical error; (2) increased flexibility regarding sample magnification changes, taxonomic lists, measurable size ranges, precision level, and output format; and (3) increased file editing abilities. Moreover, prey taxon- and size-dependent selectivities (Manly-Chesson preference index α and Strauss's linear index L) of planktivorous predators can be calculated using plankton samples from an “environment” (e.g., lake, pond, tank) in which a predator was feeding and samples from either the predator's stomach or from the “environment” after the predator had been feeding. Though designed primarily for the analysis of zooplankton, CAPAS can be useful in a variety of other analyses in which taxonomic or size composition is needed (e.g., phytoplankton enumeration, measurement and enumeration of morphological characteristics of zooplankton such as leg spines and setules, antennae segments, etc.).

Hip and ankle walking strategies: effect on peak plantar pressures and implications for neuropathic ulceration.

Treatment of neuropathic plantar ulcers often is directed at reducing excessive, repeated peak plantar pressures (PPP). The purposes of this study were to determine whether instructing a subject to walk using a hip strategy would reduce forefoot PPP and change the kinematics of walking during a single session of testing. Thirteen subjects, 7 with peripheral neuropathy and a history of a recent plantar ulcer, and 6 controls participated. PPPs were measured with an in-shoe pressure monitoring system. Kinematics were measured with a computer-assisted motion analysis system. After data were collected as subjects walked using their normal walking pattern, subjects were instructed to walk using the hip strategy by decreasing their push-off, pulling their leg forward from their hips, decreasing step length, and maintaining their normal walking velocity. Compared with using the normal (ankle) strategy, using the hip strategy showed a significant 27% decrease in forefoot PPP and a 24% increase in heel PPP. Kinematic changes were decreased plantar flexion angular velocity, hip extension range-of motion (ROM), and step length, increased dorsiflexion ROM, and hip flexion ROM, but no change in walking velocity. These findings indicate that a change in walking pattern can result in lower forefoot PPP during a single session. Assuming patients can maintain the alterations in their walking pattern, these adaptations may help to heal plantar ulcers in some patients with peripheral neuropathy.

Preferential dilation of recipient coronary arteries of the collateral circulation by intracoronary administration of nitroglycerin

Objectives. The purpose of this study was to test the hypothesis that the sensitivity to nitroglycerin of collateral vessels and recipient arteries is greater than that of donor arteries of the collateral circulation.Background. The collateral circulation responds vigorously to nitroglycerin. However, the mechanisms of the efficacy of nitroglycerin for improving collateral circulation are not fully elucidated.Methods. The diameter of donor and recipient arteries of the collateral circulation was measured with a computer-assisted analysis system in eight patients with well developed collateral vessels. Coronary angiography was repeated before and after the intracoronary injection of 50 μg of nitroglycerin.Results. After nitroglycerin, the mean diameter ± SD of donor arteries increased to 1.61 ± 0.53 from 1.29 ± 0.39 mm (p < 0.01), whereas the diameter of recipient arteries increased to 1.59 ± 0.50 from 1.10 ± 0.49 mm (p < 0.01). The change in the diameter of recipient arteries was significantly greater than that of donor arteries (52.3 ± 24.6% vs. 24.7 ± 11.5%, p < 0.05). These changes induced by the intracoronary injection of nitroglycerin were accompanied by a decrease in pacing-induced ST segment depression (0.16 ± 0.06 to 0.06 ± 0.04 mV, p < 0.01), suggesting increased flow reserve through collateral channels.Conclusions. These findings indicate that the sensitivity to nitroglycerin of recipient arteries of the collateral circulation is significantly greater than that of donor arteries. This observation may explain the strong response of the collateral circulation to nitroglycerin in patients with functionally significant collateral channels.