[Dental care to the Israeli Defense Forces' fighters].

The combat soldiers of the Israeli Defense Forces (IDF) get comprehensive dental care. The service of a combat soldier in the IDF can be divided into two periods: the period of training that includes basic training and advanced training lasting six to eight months, followed by a period of operational activity within the framework of the battalions. Throughout his service, the combat soldier is exposed to dental disease including dental caries, periodontal disease and dental trauma attributed to his terms of service with low availability to maintain adequate oral hygiene in high intensity training. There is no available data as to the dental status of new recruits. This information is needed in order to determine the level of oral and dental health among combatsoldiers in order to guarantee operational continuity. Every recruit undergoes a full dental examination in order to determine his level of oral and dental health. From this point on, dental treatment is offered and performed according to the level of oral and dental health, in order to treat the most severe levels. The dental treatment is carried out so that throughout his service, the combat soldier is summoned to various dental clinics: the base unit training clinic, clinics serving the Brigades and experts clinics. All the factors mentioned above, are designed to help increase the provision of therapy, and lead to an increase in the number of fighters who receive comprehensive dental care.

Characterization of cell motility in single heart valve interstitial cells in vitro.

Valve interstitial cells (VIC) are the most prevalent cells in the heart valve, regulating to a large extent the normal biology of the valve and its pathobiological response to disease. In the process of valve tissue repair by VICs, single cell motility is likely to be important, as it is in wound repair by most mesenchymal type cells. We designed in vitro experiments using low density monolayer cultures to study the association of morphology and motility in single VICs which expressed alpha-smooth muscle actin. We observed that the morphology of single VICs can be categorized into six types which are reminiscent of the shape of VICs seen in vivo during valve repair. Of these morphologies, round, rhomboid, tailed and spindled shaped VICs were the most common. VICs did change their morphology over time. Rhomboid cells could become tailed or spindle-shaped and vice versa. Using time-lapse imaging and immunofluorescent microscopy, we showed that VIC morphologies reflect differences in cell motility and cell-matrix interactions. Tailed and spindle-shaped VICs were the predominant motile types and were associated with few extracellular fibronectin fibrils and less focal adhesions, as demonstrated by vinculin staining. Round and rhomboid shaped VICs were less motile and were associated with prominent vinculin and extracellular fibronectin fibrils. We found that cell mitosis is an important determinant of VIC migration. Many of the motile VICs were associated with mitosis as the daughter cells separated by migrating as tailed and spindle shaped cells. Thus cell morphology is an important determinant of VIC motility.

Microtubules regulate aortic endothelial cell actin microfilament reorganization in intact and repairing monolayers.

To understand the role of microtubules and microfilaments in regulating endothelial monolayer integrity and repair, and since microtubules and microfilaments show some co-alignment in endothelial cells, we tested the hypothesis that microtubules organize microfilament distribution. Disruption of microtubules with colchicine in resting confluent aortic endothelial monolayers resulted in disruption of microfilament distribution with a loss of dense peripheral bands, an increase in actin microfilament bundles, and an associated increase of focal adhesion proteins at the periphery of the cells. However, when microfilaments were disrupted with cytochalasin B, microtubule distribution did not change. During the early stages of wound repair of aortic endothelial monolayers, microtubules and microfilaments undergo a sequential series of changes in distribution prior to cell migration. They are initially distributed randomly relative to the wound edge, then align parallel to the wound edge and then elongate perpendicular to the wound edge. When microtubules in wounded cultures were disrupted, dense peripheral bands and lamellipodia formation were lost with increases in central stress fibers. However, following microfilament disruption, microtubule redistribution was not disrupted and the microtubules elongated perpendicular to the wound edge similar to non-treated cultures. Microtubules may organize independently of microfilaments while microfilaments require microtubules to maintain normal organization in confluent and repairing aortic endothelial monolayers.

Field Evaluation of a New Sequential Sampling Technique for Determining Apple Scab "Risk".

Most fungicide sprays applied to apple orchards in the New England states are targeted at the management of apple scab. Researchers have developed action thresholds that aid in decision-making on whether early spring fungicide applications could be eliminated without a significant increase in the incidence of fruit scab at harvest. To facilitate grower adoption of these thresholds, a simplified, sequential sampling technique in autumn to determine the "scab risk" of an orchard for the following spring was proposed in the scientific literature. However, this technique had not been evaluated in the field. In autumn 1999, 2000, and 2001, orchards were evaluated using the new sequential sampling technique to determine scab risk. Risk ratings were compared with those obtained by the original, nonsequential procedure in each orchard. Data also were examined using a simulation sequential sampling computer program to determine whether or not risk ratings would change if different trees or shoots were used. In two of the assessed orchards, "delayed-spray" experiments involving two treatments (a delayed-spray and full-spray treatment) were conducted in 2000 and 2001. Delayed-spray replicates were to receive no fungicide sprays until after the third primary infection period (but before the fourth) or until the pink stage of bud development, whichever came first; full-spray replicates received fungicide sprays starting at the green-tip stage of bud development. The sequential sampling technique provided scab-risk ratings consistent with the original, nonsequential procedure, at potentially significant time savings. Also, following the delayed-spray strategy in low-risk orchards did not result in significant differences in fruit scab at harvest compared with initiating spraying at the green-tip phenological bud stage.

Understanding the role of the cytoskeleton in the complex regulation of the endothelial repair.

Actin microfilaments and microtubules are important cytoskeletal proteins that regulate endothelial repair through alterations in cell shape and through regulation of cell migration following wounding of the endothelium. Upstream pathways have been identified in the regulation of actin and microtubule organization, especially small GTPases. Recently, there have been numerous proteins suggested to be capable of regulating interaction between microtubules and microfilaments to mediate microtubule regulation of endothelial repair, an important process in limiting injury to the artery wall and in reducing the extent of arterial disease. If disrupted, a rapid repair mechanism is important in reestablishing the integrity of the endothelium in order to reestablish its function as a macromolecular barrier, a thromboresistant surface, and a biologically active tissue. Strategies to improve repair should alter the pathobiology of the atherosclerotic plaque and thus improve the prognosis of patients with atherosclerosis.

Measurement of the ultrasonic properties of human coronary arteries in vitro with a 50-MHz acoustic microscope.

Ultrasonic attenuation coefficient, wave propagation speed and integrated backscatter coefficient (IBC) of human coronary arteries were measured in vitro over the -6 dB frequency bandwidth (36 to 67 MHz) of a focused ultrasound transducer (50 MHz, focal distance 5.7 mm, f/number 1.7). Corrections were made for diffraction effects. Normal and diseased coronary artery sub-samples (N = 38) were obtained from 10 individuals at autopsy. The measured mean +/- SD of the wave speed (average over the entire vessel wall thickness) was 1581.04 +/- 53.88 m/s. At 50 MHz, the average attenuation coefficient was 4.99 +/- 1.33 dB/mm with a frequency dependence term of 1.55 +/- 0.18 determined over the 36- to 67-MHz frequency range. The IBC values were: 17.42 +/- 13.02 (sr.m)-1 for thickened intima, 11.35 +/- 6.54 (sr.m)-1 for fibrotic intima, 39.93 +/- 50.95 (sr.m)-1 for plaque, 4.26 +/- 2.34 (sr.m)-1 for foam cells, 5.12 +/- 5.85 (sr.m)-1 for media and 21.26 +/- 31.77 (sr.m)-1 for adventitia layers. The IBC results indicate the possibility for ultrasound characterization of human coronary artery wall tissue layer, including the situations of diseased arteries with the presence of thickened intima, fibrotic intima and plaque. The mean IBC normalized with respect to the mean IBC of the media layer seems promising for use as a parameter to differentiate a plaque or a thickened intima from a fibrotic intima.

Measurement of the ultrasonic properties of human coronary arteries in vitro with a 50-MHz acoustic microscope

Ultrasonic attenuation coefficient, wave propagation speed and integrated backscatter coefficient (IBC) of human coronary arteries were measured in vitro over the -6 dB frequency bandwidth (36 to 67 MHz) of a focused ultrasound transducer (50 MHz, focal distance 5.7 mm, f/number 1.7). Corrections were made for diffraction effects. Normal and diseased coronary artery sub-samples (N = 38) were obtained from 10 individuals at autopsy. The measured mean ± SD of the wave speed (average over the entire vessel wall thickness) was 1581.04 ± 53.88 m/s. At 50 MHz, the average attenuation coefficient was 4.99 ± 1.33 dB/mm with a frequency dependence term of 1.55 ± 0.18 determined over the 36- to 67-MHz frequency range. The IBC values were: 17.42 ± 13.02 (sr.m)-1 for thickened intima, 11.35 ± 6.54 (sr.m)-1 for fibrotic intima, 39.93 ± 50.95 (sr.m)-1 for plaque, 4.26 ± 2.34 (sr.m)-1 for foam cells, 5.12 ± 5.85 (sr.m)-1 for media and 21.26 ± 31.77 (sr.m)-1 for adventitia layers. The IBC results indicate the possibility for ultrasound characterization of human coronary artery wall tissue layer, including the situations of diseased arteries with the presence of thickened intima, fibrotic intima and plaque. The mean IBC normalized with respect to the mean IBC of the media layer seems promising for use as a parameter to differentiate a plaque or a thickened intima from a fibrotic intima

Microtubule-actin interactions may regulate endothelial integrity and repair.

An important mechanism for the initiation and progression of atherosclerosis is the loss of endothelial integrity, which is required for normal blood vessel function. The important components of the endothelial cell cytoskeleton system that regulate endothelial integrity include actin microfilaments and microtubules, which are both associated with protein complexes that regulate cell-cell and cell-substratum adhesion. To date, studies have shown that microfilaments are essential in maintaining the structural integrity of the endothelium while microtubules regulate the directional cell migration during repair. When microtubules are disrupted at the onset of wounding, neither centrosome reorientation, which is essential for efficient endothelial cell wound repair, nor cell migration occurs. Disruption of microfilaments is also associated with inefficient endothelial cell migration and repair. How then might these systems be associated with one another? Linker proteins, which may facilitate interaction between microtubules and actin microfilaments, have recently been identified in nonendothelial systems. It is likely that microtubule-microfilament interactions are important in the complex regulation of endothelial integrity and repair especially as they relate to atherosclerotic plaque formation.

Quantifying Alfalfa Yield Losses Caused by Foliar Diseases in Iowa, Ohio, Wisconsin, and Vermont.

Although foliar diseases of alfalfa occur throughout the United States wherever alfalfa is grown, little work has been done to quantify yield losses caused by foliar pathogens since the late 1980s. To quantify the yield losses caused by foliar diseases of alfalfa, field experiments were performed in Iowa, Ohio, Vermont, and Wisconsin from 1995 to 1998. Different fungicides and fungicide application frequencies were used to obtain different levels of foliar disease in alfalfa. Visual disease and remote sensing assessments were performed weekly to determine the relationships between disease assessments and alfalfa yield. Visual disease assessments of percentage of defoliation, disease incidence, and disease severity were performed weekly, approximately five to six times during each alfalfa growth cycle. Remote sensing assessments also were obtained weekly by measuring the percentage of sunlight reflected from alfalfa canopies using handheld, multispectral radiometers. Yield loss estimates were calculated as the yield difference between the fungicide treatment with the highest yield and the nonfungicide control, divided by the yield obtained from the highest yielding fungicide treatment × 100. Over the 4-year period, significant alfalfa yield losses (P ≤ 0.05) occurred on 22 of the 48 harvest dates for the four states. The average significant yield loss for the 22 harvests was 19.3%. Both visual and percentage of reflectance assessments were used as independent variables in linear regression models to quantify the relationships between assessments and alfalfa yield. From 1995 to 1998, visual disease assessments were performed for a total of 209 dates and remote sensing assessments were performed on 198 dates from the four states. Yield models were developed for each of these assessment dates. There were 26/209, 26/209, and 17/209 significant yield models based on percentage of defoliation, disease incidence, and disease severity, respectively. Most of the significant models were for disease assessments performed on or within 1 or 2 weeks of the date of alfalfa harvest. When the significant models were averaged, percentage of defoliation, disease incidence, and disease severity explained 51, 55, and 52% of the variation in alfalfa yield, respectively. There were a total of 68/198 significant alfalfa yield models based on remote sensing assessments, and the significant models (averaged) explained 62% of the variation in alfalfa yield. Alfalfa foliar diseases continue to have a significant negative impact on alfalfa yields in the United States and remote sensing appears to offer a better means to quantify the impact of foliar diseases on alfalfa yield compared with visual assessment methods.

An atypical chairside immediate denture: a clinical report.

This clinical report describes the fabrication of an immediate complete denture for a patient with an extensive fixed prosthesis that was no longer serviceable because of major loss of integrity of the supporting abutment teeth. The procedure, which was performed chairside, replicated the existing fixed prosthesis as part of an immediate complete denture.

Effects of anastomotic angle on vascular tissue responses at end-to-side arterial grafts.

OBJECTIVE: Hemodynamics has been implicated in the late failure of arterial bypass grafts, which frequently occurs at the distal anastomosis site. This study was designed to assess the relationship between local hemodynamics and pathologic responses of the distal anastomosis by manipulation of the angle of anastomosis of the graft, a major determinant of local hemodynamics. METHODS: End-to-side anastomoses of the right carotid to the left carotid arteries of rabbits were performed at anastomotic angles of less than 10 degrees (acute), 45 degrees (intermediate), or 90 degrees (right angle), and then the upstream left carotid arteries were ligated to simulate pathologic occlusion. We examined tissue responses on the wall of the recipient vessel opposite the anastomosis site (the bed), where unusual hemodynamic forces are imposed. RESULTS: Three months after surgery, intimal thickening was observed on the upstream portion of the acute, and more rarely, the intermediate anastomoses only. Medial thinning caused by loss of cells and matrix, and an aneurysm-like dilation, was observed in the right angle and some intermediate anastomoses, but not in the acute anastomoses. En face confocal microscopy at 3 weeks after surgery revealed severe disruption of the internal elastic lamina in all anastomotic models. Zymography and Western immunoblotting demonstrated gelatinolytic activity, caused by expression and activation of MMP-2, that was lowest in the acute anastomoses, higher in the intermediate anastomoses, and highest in the right-angle anastomoses. CONCLUSIONS: We infer that very different pathologic changes to the vessel wall are elicited when local hemodynamics is manipulated by altering the anastomotic branch angle.

Systemic and nontraditional markers of endothelial dysfunction.

Endothelial cells control the balance between a number of opposing biological processes. Injury to these cells leads to a shift in this delicate balance; the resultant endothelial dysfunction ultimately leads to atherosclerotic disease. Specific markers of endothelial dysfunction can be used to detect and monitor the progression of atherosclerosis; they can also be used to study the pathogenesis of disease. Specific markers may be indicative of a particular stage in the pathogenesis of disease. By using a rigorous screening process, various markers of endothelial dysfunction can be identified. Common markers of endothelial dysfunction that are used in clinical studies are vascular cell adhesion molecule-1, intracellular adhesion molecule-1 and fibrinogen.

Transient and steady-state effects of shear stress on endothelial cell adherens junctions.

Endothelial cells exhibit profound changes in cell shape in response to altered shear stress that may require disassembly/reassembly of adherens junction protein complexes that mediate cell-cell adhesion. To test this hypothesis, we exposed confluent porcine aortic endothelial cells to 15 dyne/cm(2) of shear stress for 0, 8.5, 24, or 48 hours, using a parallel plate flow chamber. Cells were fixed and stained with antibodies to vascular endothelial (VE) cadherin, alpha-catenin, beta-catenin, or plakoglobin. Under static conditions, staining for all proteins was intense and peripheral, forming a nearly continuous band around the cells at cell-cell junctions. After 8.5 hours of shear stress, staining was punctate and occurred only at sites of continuous cell attachment. After 24 or 48 hours of shear, staining for VE-cadherin, alpha-catenin, and beta-catenin was intense and peripheral, forming a band of "dashes" (adherens plaques) that colocalized with the ends of stress fibers that inserted along the lateral membranes of cells. Staining for plakoglobin was not observed after 24 hours of shear stress, but returned after 48 hours. Western blot analysis indicated that protein levels of VE-cadherin, alpha-catenin, and plakoglobin decreased, whereas beta-catenin levels increased after 8.5 hours of shear stress. As cell shape change reached completion (24 to 48 hours), all protein levels were upregulated except for plakoglobin, which remained below control levels. The partial disassembly of adherens junctions we have observed during shear induced changes in endothelial cell shape may have important implications for control of the endothelial permeability barrier and other aspects of endothelial cell function.

Fibroblast growth factor 2 enhances early stages of in vitro endothelial repair by microfilament bundle reorganization and cell elongation.

As endothelial cells convert from quiescent to migrating cells over 8 h along a wound edge, actin microfilaments undergo well-defined sequential changes characterized by an initial random distribution followed by a parallel and then a perpendicular orientation of microfilaments with respect to the wound edge. The latter is associated with subsequent cell migration. We tested the hypothesis that fibroblast growth factor 2 (FGF-2) can enhance the very early stages of wound repair even prior to migration and that FGF-2 enhancement of wound repair is associated with changes in the endothelial actin cytoskeleton. Using an in vitro two-sided wound model, the addition of FGF-2 at the time of wounding enhanced the extent of wound closure over 8 h. Treatment with FGF-2 was associated with significantly longer cells along the wound edge at 4 and 8 h after wounding. When treated with increasing concentrations of neutralizing FGF-2 antibody, the extent of wound closure decreased over 8 h and was associated with a decrease in cell length along the wound edge. Actin microfilaments were localized using rhodamine phalloidin and viewed using laser confocal microscopy. At 4 h after wounding, FGF-2 treatment was associated with significantly more cells along the wound expressing perpendicular microfilaments compared to untreated cells, which suggested a more rapid transition of parallel to perpendicular microfilament distribution. Thus, FGF-2 affects the very early stages of wound repair prior to migration by enhancing wound closure due to the early appearance of perpendicular microfilaments and lengthening of cells along the wound edge.

Early stages of endothelial wound repair: conversion of quiescent to migrating endothelial cells involves tyrosine phosphorylation and actin microfilament reorganization.

Endothelial repair to reestablish structural integrity following wounding is a complex process. Since the actin cytoskeleton undergoes specific changes in distribution as quiescent endothelial cells switch to activated migrating cells over a 6-h period following wounding (Lee et al. 1996), we studied tyrosine phosphorylation in association with actin microfilaments and adhesion proteins using double immunofluorescent confocal microscopy. We showed that in a confluent monolayer phosphotyrosine localized at the periphery of the cell at vinculin cell-cell adhesion sites within the actin-dense peripheral band (DPB) and centrally at talin/vinculin cell-substratum adhesion sites at the ends of central microfilaments. Over a period of 6 h following in vitro wounding there was a reduction of peripheral phosphotyrosine associated with the loss of both cell-cell adhesion sites and the DPB (stage I). Concomitantly, an increase in central phosphotyrosine was associated with an increase in cell-substratum adhesion sites and central microfilaments parallel to the wound edge (stage II), which subsequently redistributed perpendicular to the wound edge (stage III). We also localized FAK and paxillin at the ends of parallel and perpendicular central microfilaments. Immunoprecipitation of paxillin showed increased phosphotyrosine and protein levels when prominent central microfilaments were present and underwent remodeling. Inhibition of tyrosine kinases by genistein and tyrosine phosphatases by sodium orthovanadate resulted in reduced endothelial repair associated with disruption of adhesion site formation and central microfilament formation/redistribution in each stage of repair. We suggest that tyrosine phosphorylation of adhesion proteins, such as paxillin, may be important in regulating the early stages of endothelial wound repair.

Reduced in vitro repair in endothelial cells harvested from the intercostal ostia of porcine thoracic aorta.

The ability of large-vessel endothelium to repair itself rapidly after injury is important in the maintenance of its barrier function and in limiting the development and progression of atherosclerosis. Because dysfunctional repair may be involved in the pathogenesis of some atherosclerotic plaques, including those at the ostia of aortic branches, linear mechanical denuding wounds were made in confluent monolayers of endothelial cells harvested by scraping from the flow divider, the upstream wall of the intercostal branch and unbranched regions in the thoracic aorta. The extent of wound closure was significantly lower in cells derived from either side of the intercostal branches, compared with cells from unbranched areas. The wound edge of cells harvested from the flow divider and its opposite wall closed by 22+/-0.084 microm and 22+/-1.3 microm, respectively, versus control, unbranched endothelial cells (30+/-2.2 microm) at 24 hours and by 48 hours, 48+/-3.4 microm and 47+/-3.6 microm compared with control (61+/-3.4 microm). Extent of wound closure in cells harvested by scraping from unbranched regions was comparable with collagenase-harvested endothelial cells at 24 and 48 hours. Distribution of F-actin microfilaments, tubulin and centrosomes have been shown to be disrupted at the wound edge in poorly migrating cells. In our study, however, no differences were observed in cytoskeletal distribution between cells from branched, unbranched and control areas. Thus, aortic endothelial cells from the intercostal branch region show a reduced ability to repair wounds compared with cells harvested from unbranched aorta. The mechanism for this difference is currently unknown.

Alterations in endothelial F-actin microfilaments in rabbit aorta in hypercholesterolemia.

The current study tests whether hypercholesterolemia influences the distribution of endothelial cell microfilaments during the initiation and growth of fatty streak-type lesions. We classified the lesions occurring over a 20-week period into four types based on the location and extent of macrophage infiltration observed microscopically. The earliest lesion was characterized by leukocytes adherent to the endothelial surface. Minimal lesions were characterized by a few cells in the subendothelium. Intermediate lesions consisted of numerous subendothelial leukocytes in a minimally raised lesion. Advanced fatty streak lesions were elevated, with several layers of leukocytes. The organization of peripheral junctional actin (the dense peripheral band) and of central endothelial cell actin microfilament bundles was studied in each of these lesions by using fluorescent microscopy. We found that in the aorta away from branch sites and in areas away from lesions, the central microfilament distribution was unaffected by hypercholesterolemia. The macrophages entered the wall without any identifiable reorganization in the microfilaments. During the accumulation of subendothelial macrophages in minimal and intermediate lesions, stress fibers were initially increased in comparison to lesion-free areas. In raised advanced lesions, the central microfilaments became thinner and disappeared. However, at flow dividers, where central stress fibers are normally prominent, endothelial cells on the surface of intermediate lesions showed a reduction in central fibers, and peripheral bands became prominent. This finding was associated with changes in cell shape from elongated to cobblestone type. Thus, actin microfilament bundles in endothelial cells underwent substantial changes in distribution during the accumulation of subendothelial macrophages, forming hypercholesterolemia-induced fatty streak-type lesions. These changes may influence endothelial substrate adhesion, permeability, or repair after injury.

Arterial imaging: comparison of high-resolution US and MR imaging with histologic correlation.

The potential roles of intravascular ultrasound (US) and magnetic resonance (MR) imaging in evaluating the artery wall and atherosclerotic plaque were compared. Excised human femoral and carotid arteries were imaged with a 42-MHz intravascular US system and a 1.5-T MR imager equipped with enhanced gradients. In-plane resolution was 40-280 microns for US and 156 microns for MR imaging. Stained histologic tissue sections were obtained for correlation with the imaging findings. Intravascular US and MR imaging both had sufficient resolution and contrast to demonstrate arterial layers and allow distinction of atheroma. Correspondence between structures identified with the two modalities was excellent and in agreement with histologically defined arterial structures. Findings on state-of-the-art intravascular US and MR images correlate well with histologic findings in normal and diseased arteries. Intravascular US has the advantages of speed and resolution, whereas MR imaging demonstrates superior contrast in the depiction of atheroma.