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Lustig M, Epstein Y, Gefen A. An anatomically-realistic computational framework for evaluating the efficacy of protective plates in mitigating non-penetrating ballistic impacts. Comput Biol Med 2023; 166:107490. [PMID: 37738897 DOI: 10.1016/j.compbiomed.2023.107490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/03/2023] [Accepted: 09/15/2023] [Indexed: 09/24/2023]
Abstract
BACKGROUND A major threat in combat scenarios is the 'behind armor blunt trauma' (BABT) of a non-penetrating ballistic impact with a ballistic protective plate (BPP). This impact results in pressure waves that propagate through tissues, potentially causing life-threatening damage. To date, there is no standardized procedure for rapid virtual testing of the effectiveness of BPP designs. The objective of this study was to develop a novel, anatomically-accurate, finite element modeling framework, as a decision-making tool to evaluate and rate the biomechanical efficacy of BPPs in protecting the torso from battlefield-acquired non-penetrating impacts. METHODS To simulate a blunt impact with a BPP, two types of BPPs representing generic designs of threat-level III and IV plates, and a generic 5.56 mm bullet were modeled, based on their real dimensions, physical and mechanical characteristics (plate level-III is smaller, thinner, and lighter than plate level-IV). The model was validated by phantom testing. RESULTS Plate level-IV induced greater strains and stresses in the superficial tissues post the ballistic impact, due to the fact that it is larger, thicker and heavier than plate level-III; the shock wave which is transferred to the superficial tissues behind the BPP is greater in the case of a non-penetrating impact. For example - the area under volumetric tissue exposure histograms of strains and stresses for the skin and adipose tissues were 16.6-19.2% and 17.3-20.3% greater in the case of plate level-IV, for strains and stresses, respectively. The validation demonstrates a strong agreement between the physical phantom experiment and the simulation, with only a 6.37% difference between them. CONCLUSIONS Our modelling provides a versatile, powerful testing framework for both industry and clients of BPPs at the prototype design phase, or for quantitative standardized evaluations of candidate products in purchasing decisions and bids.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yoram Epstein
- School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
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2
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Ntsogo Y, Lustig M, Boyer E, Daury L, Phan G, Lambert O, Broutin I. Towards the comprehension of the assembly and opening of the MexAB-OprM efflux pump involved in the antibiotic resistance of Pseudomonas aeruginosa. Acta Cryst Sect A 2022. [DOI: 10.1107/s2053273322096188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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3
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Lustig M, Gefen A. The biomechanical efficacy of a dressing with a soft cellulose fluff core in protecting prone surgical patients from chest injuries on the operating table. Int Wound J 2022; 19:1786-1796. [PMID: 35243764 PMCID: PMC9615289 DOI: 10.1111/iwj.13783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/22/2022] [Indexed: 12/01/2022] Open
Abstract
Pressure ulcers are soft‐tissue damage associated with tissue exposure to sustained deformations and stress concentrations. In patients who are proned for ventilation or surgery, such damage may occur in the superficial chest tissues that are compressed between the rib cage and the support surface. Prophylactic dressings have been previously proven as generally effective for pressure ulcer prevention. In this study, our goal was to develop a novel computational modelling framework to investigate the biomechanical efficacy of a dressing with a soft cellulose fluff core in protecting proned surgical patients from chest pressure ulcers occurring on the operating table, due to body fixation by the Relton‐Hall frame. We compared the levels of mechanical compressive stresses developing in the soft chest tissues, above the sternum and ribs, due to the trunk weight, whilst the body is supported by the Relton‐Hall frame pads, with versus without the prophylactically applied bilateral dressings. The protective efficacy index for the extremely high stresses, above the 95th‐percentile, were 40.5%, 25.6% and 24.2% for skin, adipose and muscle, respectively, indicating that the dressings dispersed elevated soft‐tissue stresses. The current results provide additional support for using soft cellulose fluff core dressings for pressure ulcer prophylaxis, including during surgery.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
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4
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Lustig M, Schwartz D, Bryant R, Gefen A. A machine learning algorithm for early detection of heel deep tissue injuries based on a daily history of sub-epidermal moisture measurements. Int Wound J 2022; 19:1339-1348. [PMID: 35019208 PMCID: PMC9493225 DOI: 10.1111/iwj.13728] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/21/2021] [Accepted: 12/01/2021] [Indexed: 12/28/2022] Open
Abstract
Sub‐epidermal moisture is an established biophysical marker of pressure ulcer formation based on biocapacitance changes in affected soft tissues, which has been shown to facilitate early detection of these injuries. Artificial intelligence shows great promise in wound prevention and care, including in automated analyses of quantitative measures of tissue health such as sub‐epidermal moisture readings acquired over time for effective, patient‐specific, and anatomical‐site‐specific pressure ulcer prophylaxis. Here, we developed a novel machine learning algorithm for early detection of heel deep tissue injuries, which was trained using a database comprising six consecutive daily sub‐epidermal moisture measurements recorded from 173 patients in acute and post‐acute care settings. This algorithm was able to achieve strong predictive power in forecasting heel deep tissue injury events the next day, with sensitivity and specificity of 77% and 80%, respectively, revealing the clinical potential of artificial intelligence‐powered technology for hospital‐acquired pressure ulcer prevention. The current work forms the scientific basis for clinical implementation of machine learning algorithms that provide effective, early, and anatomy‐specific preventive interventions to minimise the occurrence of hospital‐acquired pressure ulcers based on routine tissue health status measurements.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Dafna Schwartz
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Ruth Bryant
- Principal Research Scientist/Nursing and President, Association for the Advancement of Wound Care (AAWC), Abbott Northwestern Hospital, part of Allina Health, Minneapolis, MN, USA
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
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5
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Lustig M, Gefen A. Computational studies of the biomechanical efficacy of a minimum tissue deformation mattress in protecting from sacral pressure ulcers in a supine position. Int Wound J 2021; 19:1111-1120. [PMID: 34725917 PMCID: PMC9284654 DOI: 10.1111/iwj.13707] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/14/2021] [Accepted: 10/20/2021] [Indexed: 11/28/2022] Open
Abstract
Sustained soft tissue exposure to localised deformations is a trigger for the formation of pressure ulcers. Immersion and envelopment are critical benchmarks that determine comfort and the pressure ulcer risk mitigation, as they have considerable influence on tissue stress concentrations near bony prominences. In the present study, we developed a computer modelling framework for quantifying the extent by which optimal envelopment disperses tissue stress concentrations near the sacrum. To compare the risk of developing a sacral pressure ulcer while lying supine on a regular foam mattress with respect to lying on a specialised, minimum tissue deformation mattress (which closely conforms to the body contours), we used a three‐dimensional anatomically‐realistic model of the adult female buttocks. The strains and stresses in the subdermal soft tissues reached peak values of 65% and 2.4 kPa for the regular mattress, respectively, but always remained below 45% and 1.2 kPa for the minimum tissue deformation mattress, which indicates longer safe times for supine support on the latter mattress. Our work demonstrates that alleviation of localised, sustained stress concentrations through good immersion and envelopment of the support surface protects from pressure ulcers, and has the potential to relieve chronic pain which is associated with the pressure ulcer risk.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
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6
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Mor-Yossef Moldovan L, Kislev N, Lustig M, Pomeraniec L, Benayahu D. Biomechanical stimulation effects on the metabolism of adipocyte. J Cell Physiol 2020; 235:8702-8713. [PMID: 32330316 DOI: 10.1002/jcp.29714] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/18/2020] [Accepted: 04/05/2020] [Indexed: 12/30/2022]
Abstract
Adipose tissue plays a leading role in obesity, which, in turn, can lead to Type 2 diabetes. Adipocytes (AD) respond to the biomechanical stimulation experienced in fat tissue under static stretch during prolonged sitting or lying. To investigate the effect of such chronic stimulation on adipocyte cell metabolism, we used an in vitro system to mimic the static stretch conditions. Under in vitro culture stretching, cells were analyzed at the single-cell level and we measured an increase in the projected area of the AD and higher content of lipid droplets. A decrease in the projected area of these cells' nucleus is associated with peroxisome proliferator-activated receptor-gamma expression and heterochromatin. This is the first study to reveal proteins that were altered under static stretch following a mass spectrometry analysis and main pathways that affect cell fate and metabolism. Bioinformatics analysis of the proteins indicated an increase in mitochondrial activity and associated pathways under static stretch stimulation. Quantification of the mitochondrial activity by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay and the ATPase related proteins specifically measured ATP5B indicated an increase in adipogenesis which points to a higher rate of cell metabolism under static stretch. In summary, our results elaborate on the metabolism of AD exposed to biomechanical stimulation, that is, associated with altered cellular protein profile and thereby influenced cell fate. The static stretch stimulation accelerated adipocyte differentiation through increased mitochondrial activity. Hence, in this study, we introduce a new perspective in understanding the molecular regulation of mechano-transduction in adipogenesis.
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Affiliation(s)
- Lisa Mor-Yossef Moldovan
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nadav Kislev
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Leslie Pomeraniec
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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7
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Lustig M, Wiggermann N, Gefen A. How patient migration in bed affects the sacral soft tissue loading and thereby the risk for a hospital-acquired pressure injury. Int Wound J 2020; 17:631-640. [PMID: 32048476 PMCID: PMC7217162 DOI: 10.1111/iwj.13316] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/16/2020] [Accepted: 01/27/2020] [Indexed: 12/16/2022] Open
Abstract
Head‐of‐bed (HOB) elevation is a common clinical practice in hospitals causing the patient's body to slide down in bed because of gravity. This migration effect likely results in tissue shearing between the sacrum and the support surface, which increases the risk for pressure injuries. StayInPlace (HillRom Inc.) is a commercial migration‐reduction technology (MRT) incorporated in intensive care bedframes. Yet, the effects of migration‐reduction on tissue shear stresses during HOB elevation are unknown. We analysed relationships between migration and resulting sacral soft tissue stresses by combining motion analysis and three‐dimensional finite element modelling of the buttocks. Migration data were collected for 10 subjects, lying supine on two bedframe types with and without MRT, and at HOB elevations of 45°/65°. Migration data were used as displacement boundary conditions for the modelling to calculate tissue stress exposures. Migration values for the conventional bed were 1.75‐ and 1.6‐times greater than those for the migration‐reduction bed, for elevations of 45° and 65°, respectively (P < .001). The modelling showed that the farther the migration, the greater the tissue stress exposures. Internal stresses were 1.8‐fold greater than respective skin stresses. Our results, based on the novel integrated experimental‐computational method, point to clear biomechanical benefits in minimising migration using MRT.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
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8
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Abstract
Adipogenesis is a developmental process in which an elongated preadipocyte differentiates to a round adipocyte along with the accumulation of lipid droplets. In the present study, we focus on the study of cell motility at the single-cell level, toward expanding our knowledge regarding the cytoskeleton alteration during differentiation; since-cell motility is mediated by cytoskeletal components. We used the holographic-microscopy live imaging technique to evaluate, for the first time in the literature, differences between the motility of nondifferentiated preadipocytes and differentiated mature adipocytes in living cell cultures over time. We revealed that mean motility speed of preadipocytes was significantly higher (fourfold) than that of adipocytes, and that the movement of preadipocytes is less consistent and more extensive. Furthermore, we found that preadipocytes tend to migrate to farther distances, while mature adipocytes remain relatively close to their original location. The results presented here are in agreement with the fact that the cytoskeleton of adipocytes is altered during differentiation and similarly, points to the fact that the cell-sensing mechanisms are changing during differentiation. Our research paves the way to gain better insights of the differentiation process and its implications on larger scale systems in the context of obesity.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yuliya Zadka
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Irena Levitsky
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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9
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Lustig M, Feng Q, Payan Y, Gefen A, Benayahu D. Noninvasive Continuous Monitoring of Adipocyte Differentiation: From Macro to Micro Scales. Microsc Microanal 2019; 25:119-128. [PMID: 30712528 DOI: 10.1017/s1431927618015520] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
3T3-L1 cells serve as model systems for studying adipogenesis and research of adipose tissue-related diseases, e.g. obesity and diabetes. Here, we present two novel and complementary nondestructive methods for adipogenesis analysis of living cells which facilitate continuous monitoring of the same culture over extended periods of time, and are applied in parallel at the macro- and micro-scales. At the macro-scale, we developed visual differences mapping (VDM), a novel method which allows to determine level of adipogenesis (LOA)-a numerical index which quantitatively describes the extent of differentiation in the whole culture, and percentage area populated by adipocytes (PAPBA) across a whole culture, based on the apparent morphological differences between preadipocytes and adipocytes. At the micro-scale, we developed an improved version of our previously published image-processing algorithm, which now provides data regarding single-cell morphology and lipid contents. Both methods were applied here synergistically for measuring differentiation levels in cultures over multiple weeks. VDM revealed that the mean LOA value reached 1.11 ± 0.06 and the mean PAPBA value reached >60%. Micro-scale analysis revealed that during differentiation, the cells transformed from a fibroblast-like shape to a circular shape with a build-up of lipid droplets. We predict a vast potential for implementation of these methods in adipose-related pharmacological research, such as in metabolic-syndrome studies.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering,Tel Aviv University,Tel Aviv 6997801,Israel
| | - Qingling Feng
- Key Laboratory of Advanced Materials of Ministry of Education of China,School of Materials Science and Engineering, Tsinghua University,Beijing 100084,China
| | - Yohan Payan
- CNRS, Grenoble INP, TIMC-IMAG, University of Grenoble Alpes,Grenoble F-38000,France
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering,Tel Aviv University,Tel Aviv 6997801,Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology,Sackler School of Medicine, Tel Aviv University,Tel Aviv 6997801,Israel
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10
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Mor-Yossef Moldovan L, Lustig M, Naftaly A, Mardamshina M, Geiger T, Gefen A, Benayahu D. Cell shape alteration during adipogenesis is associated with coordinated matrix cues. J Cell Physiol 2018; 234:3850-3863. [PMID: 30191963 DOI: 10.1002/jcp.27157] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 07/10/2018] [Indexed: 12/14/2022]
Abstract
Obesity has become one of the leading pathophysiologic disorders in recent years. Adipose tissue is the main tissue related to obesity and is known to play a role in various physiological complications, including type 2 diabetes. To better understand how the fat tissue develops, we used an in vitro live cell imaging system to quantify the adipogenesis by means of nondestructive digital imaging to monitor the accumulation of intracellular lipid droplets (LDs), a hallmark of adipogenesis, from the macro- to the micro-scale. Analyzing the cells' shape at the single-cell level allows to quantify the cells' shape change from a fibroblast to spherical morphology, indicating the start of adipogenesis. To reveal the molecular alterations, we applied a proteomic approach using high-resolution mass spectrometry of the proliferation, confluent fibroblasts and of adipocytes. During this process, we noted the reorganization of the cells' extracellular matrix (ECM) network microenvironment from fibrillary collagen types I, III and V to collagens IV and VI, which affected the cells niche. The changes in ECM are translated for cytoskeleton remodeling according to cell fate-determining mechanisms. We quantified the cytoskeleton rearrangement of long oriented actin fibers or short cortical and disorganized fibers, associated with LDs accumulation in adipocytes. Developing in vitro models and analytical methods enable us to study differentiation into adipocytes that will advance our understanding regarding the niche conditions that affect adipogenesis. Consequently, this will enable the development of new modalities to prevent obesity and its deleterious outcomes and to develop potential treatments to battle pathophysiology-related diseases.
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Affiliation(s)
- Lisa Mor-Yossef Moldovan
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Alex Naftaly
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mariya Mardamshina
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tamar Geiger
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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11
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Lustig M, Gefen A, Benayahu D. Adipogenesis and lipid production in adipocytes subjected to sustained tensile deformations and elevated glucose concentration: a living cell-scale model system of diabesity. Biomech Model Mechanobiol 2018; 17:903-913. [PMID: 29335836 DOI: 10.1007/s10237-017-1000-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/29/2017] [Indexed: 12/15/2022]
Abstract
Adipocyte fate commitment is characterized by morphological changes of fibroblastic pre-adipocyte cells, and specifically by accumulation of lipid droplets (LDs) as part of the adipogenesis metabolism. Formation of LDs indicates the production of triglycerides from glucose through an insulin-regulated glucose internalization process. In obesity, adipocytes typically become insulin resistant, and glucose transport into the cells is impaired, resulting in type 2 diabetes. In the present study, we monitored the adipogenesis in 3T3-L1 cultured cells exposed to high (450 mg/dL hyperglycemia) and low (100 mg/dL physiological) glucose concentrations, in a novel cell culture model system of diabesity. In addition to glucose conditions, cells were concurrently exposed to different substrate tensile strains (12% and control) based on our prior work which revealed that adipogenesis is accelerated in cultures subjected to static, chronic substrate tensile deformations. Phase-contrast images were taken throughout the adipogenesis process (3 weeks) and were analyzed by an image processing algorithm which quantitatively monitors cell differentiation and lipid accumulation (number of LDs per cell and their radius as well as cell size and shape). The results indicated that high glucose concentrations and substrate tensile strains delivered to adipocytes accelerated lipid production by 1.7- and 1.4-fold, respectively. In addition, significant changes in average cell projected area and in other morphological attributes were observed during the differentiation process. The importance of this study is in characterizing the adipogenesis parameters as potential read-outs that can predict the occurrence of insulin resistance in the development of diabesity.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.
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12
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Lustig M, Levy A, Kopplin K, Ovadia-Blechman Z, Gefen A. Beware of the toilet: The risk for a deep tissue injury during toilet sitting. J Tissue Viability 2017; 27:23-31. [PMID: 28446371 DOI: 10.1016/j.jtv.2017.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 12/01/2022]
Abstract
A pressure injury (PrI) compromises quality of life and can be life-threatening. The fundamental cause of PrIs is sustained deformations in weight-bearing soft tissues, e.g., during prolonged sitting on inadequate surfaces such as a toilet seat. In nursing homes and geriatric facilities, patients need assistance using the restroom, and patients being left on the toilet for tens-of-minutes is a real-world scenario, unfortunately. Nevertheless, there are no published studies regarding sustained tissue loads during toilet sitting and their effects on tissue physiology. Here, the biomechanical and microcirculatory responses of the buttock tissues to toilet sitting were investigated using finite element modeling and cutaneous hemodynamic measurements, to explore the potential etiology of PrIs occurring on the toilet. We found that prolonged sitting on toilet seats involves a potential risk for PrI development, the extent of which is affected by the seat design. Additionally, we found that specialized toilet seat cushions are able to reduce this risk, by lowering instantaneous tissue exposures to internal stresses (by up to 88%) and maintaining reduced interface pressures. Furthermore, hemodynamic variables were altered during the toilet sitting; in particular, tcPO2 was decreased by 49% ± 7% (44 ± 2[mmHg] to 22 ± 4[mmHg]) during sitting. The current study confirms that investing in expensive PrI prevention (PIP) products is likely to be ineffective for an immobilized patient who is left to sit on a bare toilet seat for long times. This argument highlights the need for a holistic-care approach, employing PIP devices that span across the entire environment where bodyweight forces apply to tissues.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Ayelet Levy
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Kara Kopplin
- Research & Innovation, Permobil Group, Belleville, IL, USA
| | - Zehava Ovadia-Blechman
- Department of Medical Engineering, Afeka Tel Aviv Academic College of Engineering, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
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13
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Vasanawala S, Murphy M, Alley M, Lai P, Keutzer K, Pauly J, Lustig M. PRACTICAL PARALLEL IMAGING COMPRESSED SENSING MRI: SUMMARY OF TWO YEARS OF EXPERIENCE IN ACCELERATING BODY MRI OF PEDIATRIC PATIENTS. Proc IEEE Int Symp Biomed Imaging 2011; 2011:1039-1043. [PMID: 24443670 DOI: 10.1109/isbi.2011.5872579] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
For the last two years, we have been experimenting with applying compressed sensing parallel imaging for body imaging of pediatric patients. It is a joint-effort by teams from UC Berkeley, Stanford University and GE Healthcare. This paper aims to summarize our experience so far. We describe our acquisition approach: 3D spoiled-gradient-echo with poisson-disc random undersampling of the phase encodes. Our re-construction approach: ℓ1-SPIRiT, an iterative autocalibrating parallel imaging reconstruction that enforces both data consistency and joint-sparsity in the wavelet domain. Our implementation: an on-line parallelized implementation of ℓ1-SPIRiT on multi-core CPU and General Purpose Graphics Processors (GPGPU) that achieves sub-minute 3D reconstructions with 8-channels. Clinical results showing higher quality reconstruction and better diagnostic confidence than parallel imaging alone at accelerations on the order of number of coils.
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Affiliation(s)
| | - Mj Murphy
- Electrical Engineering and Computer Science, University of California, Berkeley
| | | | | | - K Keutzer
- Electrical Engineering and Computer Science, University of California, Berkeley
| | - Jm Pauly
- Electrical Engineering, Stanford University
| | - M Lustig
- Electrical Engineering and Computer Science, University of California, Berkeley
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14
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Lehmann C, Bac VH, Pavlovic D, Lustig M, Maier S, Feyerherd F, Usichenko TI, Meissner K, Haase H, Jünger M, Wendt M, Heidecke CD, Gründling M. Metronidazole improves intestinal microcirculation in septic rats independently of bacterial burden. Clin Hemorheol Microcirc 2006; 34:427-38. [PMID: 16614467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
To explore the effects of metronidazole (Me) on intestinal microcirculation in septic rats, intravital microscopy (IVM) following 16 hours of colon ascendens stent peritonitis (CASP model) was used. Four groups of animals were studied: control group (sham operation) and CASP group, each with and without Me treatment (10 mg/kg i.v.). In order to investigate the substance-specific effects of Me independently of the antibacterial effects within a pathologically altered microcirculation, a second experimental series with lipopolysaccharide challenge (LPS model) was carried out. The LPS model consisted of the four groups (control animals and LPS animals (15 mg/kg i.v. LPS from E. coli) with and without Me). IVM in the LPS experiments was performed following a two hour observation period. Me treated CASP or LPS animals, as compared with untreated, demonstrated significant improvement of functional capillary density (FCD) of the intestinal wall. The increase in the number of leukocytes firmly adhered to the endothelium (leukocyte sticking) in the untreated CASP or LPS animals within the V1 venules of the intestinal submucosal layer, was significantly reduced in the Me treated animals. In conclusion, Me exerts beneficial anti-bacterial and anti-inflammatory effects within the septic microcirculation.
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Affiliation(s)
- Ch Lehmann
- Klinik für Anästhesiologie und Intensivmedizin, Ernst-Moritz-Arndt-Universität Greifswald, Germany.
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Lustig M, Zanazzi G, Sakurai T, Blanco C, Levinson SR, Lambert S, Grumet M, Salzer JL. Nr-CAM and neurofascin interactions regulate ankyrin G and sodium channel clustering at the node of Ranvier. Curr Biol 2001; 11:1864-9. [PMID: 11728309 DOI: 10.1016/s0960-9822(01)00586-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Voltage-dependent sodium (Na(+)) channels are highly concentrated at nodes of Ranvier in myelinated axons and play a key role in promoting rapid and efficient conduction of action potentials by saltatory conduction. The molecular mechanisms that direct their localization to the node are not well understood but are believed to involve contact-dependent signals from myelinating Schwann cells and interactions of Na(+) channels with the cytoskeletal protein, ankyrin G. Two cell adhesion molecules (CAMs) expressed at the axon surface, Nr-CAM and neurofascin, are also linked to ankyrin G and accumulate at early stages of node formation, suggesting that they mediate contact-dependent Schwann cell signals to initiate node development. To examine the potential role of Nr-CAM in this process, we treated myelinating cocultures of DRG (dorsal root ganglion) neurons and Schwann cells with an Nr-CAM-Fc (Nr-Fc) fusion protein. Nr-Fc had no effect on initial axon-Schwann cell interactions, including Schwann cell proliferation, or on the extent of myelination, but it strikingly and specifically inhibited Na(+) channel and ankyrin G accumulation at the node. Nr-Fc bound directly to neurons and clustered and coprecipitated neurofascin expressed on axons. These results provide the first evidence that neurofascin plays a major role in the formation of nodes, possibly via interactions with Nr-CAM.
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Affiliation(s)
- M Lustig
- Department of Pharmacology, New York University Medical Center, 550 First Avenue, New York, NY 10016, USA
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17
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Sakurai T, Lustig M, Babiarz J, Furley AJ, Tait S, Brophy PJ, Brown SA, Brown LY, Mason CA, Grumet M. Overlapping functions of the cell adhesion molecules Nr-CAM and L1 in cerebellar granule cell development. J Cell Biol 2001; 154:1259-73. [PMID: 11564762 PMCID: PMC2150806 DOI: 10.1083/jcb.200104122] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The structurally related cell adhesion molecules L1 and Nr-CAM have overlapping expression patterns in cerebellar granule cells. Here we analyzed their involvement in granule cell development using mutant mice. Nr-CAM-deficient cerebellar granule cells failed to extend neurites in vitro on contactin, a known ligand for Nr-CAM expressed in the cerebellum, confirming that these mice are functionally null for Nr-CAM. In vivo, Nr-CAM-null cerebella did not exhibit obvious histological defects, although a mild size reduction of several lobes was observed, most notably lobes IV and V in the vermis. Mice deficient for both L1 and Nr-CAM exhibited severe cerebellar folial defects and a reduction in the thickness of the inner granule cell layer. Additionally, anti-L1 antibodies specifically disrupted survival and maintenance of Nr-CAM-deficient granule cells in cerebellar cultures treated with antibodies. The combined results indicate that Nr-CAM and L1 play a role in cerebellar granule cell development, and suggest that closely related molecules in the L1 family have overlapping functions.
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Affiliation(s)
- T Sakurai
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
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18
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Lustig M, Erskine L, Mason CA, Grumet M, Sakurai T. Nr-CAM expression in the developing mouse nervous system: ventral midline structures, specific fiber tracts, and neuropilar regions. J Comp Neurol 2001; 434:13-28. [PMID: 11329126 DOI: 10.1002/cne.1161] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Nr-CAM is a member of the L1 subfamily of cell adhesion molecules (CAMs) that belong to the immunoglobulin superfamily. To explore the role of Nr-CAM in the developing nervous system, we prepared specific antibodies against both chick and mouse Nr-CAM using recombinant Fc fusion proteins of chick Nr-CAM and mouse Nr-CAM, respectively. First, we show the specificity of the new anti-chick Nr-CAM antibody compared with a previously employed antibody using the expression patterns of Nr-CAM in the chick spinal cord and floor plate and on commissural axons, where Nr-CAM has been implicated in axon guidance. Using the anti-mouse Nr-CAM antibody, we then studied the expression patterns of Nr-CAM in the developing mouse nervous system along with the patterns of two related CAMs, L1, which labels most growing axons, and TAG-1, which binds to Nr-CAM and has a more restricted distribution. Major sites that are positive for Nr-CAM are specialized glial formations in the ventral midline, including the floor plate in the spinal cord, the hindbrain and midbrain, the optic chiasm, and the median eminence in the forebrain. Similar to what is seen in the chick spinal cord, Nr-CAM is expressed on crossing fibers as they course through these areas. In addition, Nr-CAM is found in crossing fiber pathways, including the anterior commissure, corpus callosum, and posterior commissure, and in nondecussating pathways, such as the lateral olfactory tract and the habenulointerpeduncular tract. Nr-CAM, for the most part, is colocalized with TAG-1 in all of these systems. Based on in vitro studies indicating that the Nr-CAM-axonin-1/TAG-1 interaction is involved in peripheral axonal growth and guidance in the spinal cord [Lustig et al. (1999) Dev Biol 209:340-351; Fitzli et al. (2000) J Cell Biol 149:951-968], the expression patterns described herein implicate a role for this interaction in central nervous system axon growth and guidance, especially at points of decussation. Nr-CAM also is expressed in cortical regions, such as the olfactory bulb. In the hippocampus, however, TAG-1-positive areas are segregated from Nr-CAM-positive areas, suggesting that, in neuropilar regions, Nr-CAM interacts with molecules other than TAG-1.
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Affiliation(s)
- M Lustig
- Department of Pharmacology, New York University Medical Center, New York, New York 10016, USA
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20
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Rios JC, Melendez-Vasquez CV, Einheber S, Lustig M, Grumet M, Hemperly J, Peles E, Salzer JL. Contactin-associated protein (Caspr) and contactin form a complex that is targeted to the paranodal junctions during myelination. J Neurosci 2000; 20:8354-64. [PMID: 11069942 PMCID: PMC6773165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Specialized paranodal junctions form between the axon and the closely apposed paranodal loops of myelinating glia. They are interposed between sodium channels at the nodes of Ranvier and potassium channels in the juxtaparanodal regions; their precise function and molecular composition have been elusive. We previously reported that Caspr (contactin-associated protein) is a major axonal constituent of these junctions (Einheber et al., 1997). We now report that contactin colocalizes and forms a cis complex with Caspr in the paranodes and juxtamesaxon. These proteins coextract and coprecipitate from neurons, myelinating cultures, and myelin preparations enriched in junctional markers; they fractionate on sucrose gradients as a high-molecular-weight complex, suggesting that other proteins may also be associated with this complex. Neurons express two contactin isoforms that differ in their extent of glycosylation: a lower-molecular-weight phosphatidylinositol phospholipase C (PI-PLC)-resistant form is associated specifically with Caspr in the paranodes, whereas a higher-molecular-weight form of contactin, not associated with Caspr, is present in central nodes of Ranvier. These results suggest that the targeting of contactin to different axonal domains may be determined, in part, via its association with Caspr. Treatment of myelinating cocultures of Schwann cells and neurons with RPTPbeta-Fc, a soluble construct containing the carbonic anhydrase domain of the receptor protein tyrosine phosphatase beta (RPTPbeta), a potential glial receptor for contactin, blocks the localization of the Caspr/contactin complex to the paranodes. These results strongly suggest that a preformed complex of Caspr and contactin is targeted to the paranodal junctions via extracellular interactions with myelinating glia.
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MESH Headings
- Animals
- Cell Adhesion Molecules, Neuronal/chemistry
- Cell Adhesion Molecules, Neuronal/metabolism
- Cells, Cultured
- Centrifugation, Density Gradient
- Coculture Techniques
- Contactins
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Humans
- Immunoglobulin Fc Fragments/genetics
- Intercellular Junctions/metabolism
- Molecular Weight
- Myelin Sheath/metabolism
- Nerve Tissue Proteins/genetics
- Neurons/cytology
- Neurons/metabolism
- Phosphatidylinositol Diacylglycerol-Lyase
- Phosphoinositide Phospholipase C
- Protein Structure, Tertiary/genetics
- Protein Tyrosine Phosphatases/genetics
- Ranvier's Nodes/metabolism
- Rats
- Receptor-Like Protein Tyrosine Phosphatases, Class 5
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Schwann Cells/cytology
- Schwann Cells/metabolism
- Subcellular Fractions/chemistry
- Type C Phospholipases/metabolism
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Affiliation(s)
- J C Rios
- Department of Cell Biology, New York University School of Medicine, New York, New York 10016, USA
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21
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Affiliation(s)
- R D Strous
- Beer Yaakov Mental Health Center, Israel
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22
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Abstract
One approach for risk assessment of cancer is the evaluation of polymorphic enzymes involved in cancer using molecular tools. Phase II enzymes are involved in the detoxification of several drugs, environmental substances and carcinogenic compounds. Here, we analyzed enzymes for their putative relevance in urinary bladder cancer. The hereditable enzyme polymorphism of arylamine N-acetyltransferase 2 (NAT2) and glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) was studied in 157 hospital-based patients and in 223 control subjects. Slow acetylation was not observed to be a significant risk factor of developing bladder cancer (OR: 1.33; 95% CI 0.85-2.09). One genotype responsible for slow acetylation (NAT2*5B/*6A) was observed significantly more frequently in bladder cancer patients compared with control subjects (OR: 1.63; 95% CI 1.03-2.58). Gender-specific effects were observed when patients were divided into subgroups. In male patients, slow acetylators were identified as carrying a significant increased risk of developing bladder cancer, in particular when the genotype NAT2*5B/*6A was combined with the GSTM1 null genotype (OR: 4.39; 95% CI 1.98-9.74). By contrast, the same genotype combination significantly protected female patients from bladder cancer (OR: 0.21; 95% CI 0.06-0.80).
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Affiliation(s)
- E Schnakenberg
- Center for Human Genetics and Genetic Counselling, University of Bremen, Germany
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23
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Hendler T, Goshen E, Tadmor R, Lustig M, Zwas ST, Zohar J. Evidence for striatal modulation in the presence of fixed cortical injury in obsessive-compulsive disorder (OCD). Eur Neuropsychopharmacol 1999; 9:371-6. [PMID: 10523043 DOI: 10.1016/s0924-977x(98)00039-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A patient with obsessive-compulsive disorder (OCD) onset resulting from a traumatic head injury underwent longitudinal brain imaging evaluation. Structural and functional brain imaging studies were repeatedly performed before and after treatment. Computerized tomography (CT) demonstrated bilateral prefrontal contusions immediately following the trauma and prior to the onset of OCD. Magnetic resonance imaging (MRI) demonstrated bilateral cortical abnormalities in the prefrontal and anterior-temporal regions a few months following the onset of OCD. Almost concurrently, single photon emission computerised tomography (SPECT) demonstrated bilateral perfusion deficits in fronto-temporal regions, and asymmetric increased perfusion in the anterior striatum. Six months later, after clinical improvement, a second SPECT study demonstrated improvement of brain perfusion, mostly in the striatum. The reflection of these results on a possible model of brain pathogenesis in OCD, and the role of brain imaging in neuropsychiatric evaluation, are demonstrated.
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Affiliation(s)
- T Hendler
- Department of Psychiatry, The Chain Sheba Medical Center, Tel Hashomer, Israel.
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Matise MP, Lustig M, Sakurai T, Grumet M, Joyner AL. Ventral midline cells are required for the local control of commissural axon guidance in the mouse spinal cord. Development 1999; 126:3649-59. [PMID: 10409510 DOI: 10.1242/dev.126.16.3649] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Specialized cells at the midline of the central nervous system have been implicated in controlling axon projections in both invertebrates and vertebrates. To address the requirement for ventral midline cells in providing cues to commissural axons in mice, we have analyzed Gli2 mouse mutants, which lack specifically the floor plate and immediately adjacent interneurons. We show that a Dbx1 enhancer drives tau-lacZ expression in a subpopulation of commissural axons and, using a reporter line generated from this construct, as well as DiI tracing, we find that commissural axons projected to the ventral midline in Gli2(−/−) embryos. Netrin1 mRNA expression was detected in Gli2(−/−) embryos and, although much weaker than in wild-type embryos, was found in a dorsally decreasing gradient. This result demonstrates that while the floor plate can serve as a source of long-range cues for C-axons in vitro, it is not required in vivo for the guidance of commissural axons to the ventral midline in the mouse spinal cord. After reaching the ventral midline, most commissural axons remained clustered in Gli2(−/−) embryos, although some were able to extend longitudinally. Interestingly, some of the longitudinally projecting axons in Gli2(−/−) embryos extended caudally and others rostrally at the ventral midline, in contrast to normal embryos in which virtually all commissural axons turn rostrally after crossing the midline. This finding indicates a critical role for ventral midline cells in regulating the rostral polarity choice made by commissural axons after they cross the midline. In addition, we provide evidence that interactions between commissural axons and floor plate cells are required to modulate the localization of Nr-CAM and TAG-1 proteins on axons at the midline. Finally, we show that the floor plate is not required for the early trajectory of motoneurons or axons of the posterior commissure, whose projections are directed away from the ventral midline in both WT and Gli2(−/−) embryos, although they are less well organized in Gli2(−/−)mutants.
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Affiliation(s)
- M P Matise
- Howard Hughes Medical Institute and Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
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25
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Hermo L, Lustig M, Lefrancois S, Argraves WS, Morales CR. Expression and regulation of LRP-2/megalin in epithelial cells lining the efferent ducts and epididymis during postnatal development. Mol Reprod Dev 1999; 53:282-93. [PMID: 10369389 DOI: 10.1002/(sici)1098-2795(199907)53:3<282::aid-mrd4>3.0.co;2-a] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Low density lipoprotein receptor-related protein-2/megalin (LRP-2) is a receptor belonging to the low density lipoprotein receptor family that mediates endocytosis and lysosomal degradation of a variety of ligands including apolipoprotein J (Apo J)/clusterin/SGP-2. LRP-2 has been shown to be expressed regionally in the adult rat epididymis. In this study, we describe the pattern of expression of LRP-2 in the efferent ducts and epididymis during postnatal development of the rat and examine the role of testicular luminally derived substances on its expression. The expression of LRP-2 was analyzed immunocytochemically in tissues of normal animals ranging in age from postnatal day 7-90 and in 15-day-old efferent-duct-ligated animals sacrificed at later ages. In the efferent ducts, LRP-2 expression, appearing as a dense band on the apical surface of the nonciliated epithelial cells, was noted as early as day 7, well before the entry of sperm, Sertoli-cell-derived secretory products, and high levels of androgens. Efferent duct ligation studies further revealed that expression under this condition was comparable to controls at all later ages examined, suggesting that the factor regulating its expression was not a luminally derived testicular substance. In normal untreated animals, LRP-2 expression was not apparent at any of the ages examined in the proximal initial segment of the epididymis. By comparison, the distal initial segment, although having no LRP-2 expression from 7-15 days, showed expression in principal cells by day 21 which intensified at days 29 and 39. However, by day 49 and at later ages (56 and 90), LRP-2 immunoreactivity over principal cells became spotty or with weak or moderate reactivity in some cells and none in others. LRP-2 expression in the intermediate zone, proximal caput, corpus, and cauda regions also appeared in principal cells by day 21, intensified at days 29 and 39 and persisted as such at all later ages examined, correlating with high levels of androgens shown to occur by day 39. Although LRP-2 expression in the distal caput region was evident in principal cells at days 21 and 29, it became spotty with weak, moderate, or absent reactivity over principal cells at all later ages. These data suggest that LRP-2 expression is under the influence of both stimulatory and region-specific inhibitory factors. Analysis of 15-day-old efferent-duct-ligated animals at all later ages examined revealed that there was no change in LRP-2 expression along the entire epididymis, suggesting that both the stimulatory and inhibitory factors are not luminally derived testicular substances. The observed pattern of LRP-2 expression in all regions of the epididymis, except the distal caput region, was similar to that described for Apo J internalization by principal cells during postnatal development, showing a correlation between LRP-2 expression and its ligand, Apo J. In summary, LRP-2 expression in the epididymis undergoes region-specific changes during postnatal development and appears to be influenced by both stimulatory and inhibitory factors.
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Affiliation(s)
- L Hermo
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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26
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Abstract
Nr-CAM is a neuronal cell adhesion molecule (CAM) belonging to the immunoglobulin superfamily that has been implicated as a ligand for another CAM, axonin-1, in guidance of commissural axons across the floor plate in the spinal cord. Nr-CAM also serves as a neuronal receptor for several other cell surface molecules, but its role as a ligand in neurite outgrowth is poorly understood. We studied this problem using a chimeric Fc-fusion protein of the extracellular region of Nr-CAM (Nr-Fc) and investigated potential neuronal receptors in the developing peripheral nervous system. A recombinant Nr-CAM-Fc fusion protein, containing all six Ig domains and the first two fibronectin type III repeats of the extracellular region of Nr-CAM, retains cellular and molecular binding activities of the native protein. Injection of Nr-Fc into the central canal of the developing chick spinal cord in ovo resulted in guidance errors for commissural axons in the vicinity of the floor plate. This effect is similar to that resulting from treatment with antibodies against axonin-1, confirming that axonin-1/Nr-CAM interactions are important for guidance of commissural axons through a spatially and temporally restricted Nr-CAM positive domain in the ventral spinal cord. When tested as a substrate, Nr-Fc induced robust neurite outgrowth from dorsal root ganglion and sympathetic ganglion neurons, but it was not effective for tectal and forebrain neurons. The peripheral but not the central neurons expressed high levels of axonin-1 both in vitro and in vivo. Moreover, antibodies against axonin-1 inhibited Nr-Fc-induced neurite outgrowth, indicating that axonin-1 is a neuronal receptor for Nr-CAM on these peripheral ganglion neurons. The results demonstrate a role for Nr-CAM as a ligand in axon growth by a mechanism involving axonin-1 as a neuronal receptor and suggest that dynamic changes in Nr-CAM expression can modulate axonal growth and guidance during development.
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Affiliation(s)
- M Lustig
- Department of Pharmacology, NYU Medical Center, 550 First Avenue, New York, New York, 10016, USA
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27
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Sasson Y, Zohar J, Chopra M, Lustig M, Iancu I, Hendler T. Epidemiology of obsessive-compulsive disorder: a world view. J Clin Psychiatry 1997; 58 Suppl 12:7-10. [PMID: 9393390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The worldwide prevalence of obsessive-compulsive disorder (OCD) is approximately 2% of the general population. Symptoms of OCD include fear of contamination by dirt or germs; constant checking; repetitive, intrusive thoughts of a somatic, aggressive, or sexual nature; extreme slowness; and an inordinate concern with orderliness and symmetry. Differential diagnosis is sometimes complicated by the overlap between OCD and obsessive-compulsive personality disorder (OCPD). The most common complication of OCD is depression. However, while both serotonergic and nonserotonergic antidepressants are effective in treating patients with depression, only serotonergic medications are effective in treating OCD patients. Because OCD patients often attempt to conceal their symptoms, it is incumbent on clinicians to screen for OCD in every mental status examination, since appropriate treatment can often result in improved quality of life.
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Affiliation(s)
- Y Sasson
- Division of Psychiatry, Chaim Sheba Medical Center, Ramat-Gan, Israel
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28
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Shiga T, Lustig M, Grumet M, Shirai T. Cell adhesion molecules regulate guidance of dorsal root ganglion axons in the marginal zone and their invasion into the mantle layer of embryonic spinal cord. Dev Biol 1997; 192:136-48. [PMID: 9405103 DOI: 10.1006/dbio.1997.8742] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In order to elucidate the mechanisms regulating the projections of dorsal root ganglion (DRG) axons in the dorsal funiculus and invasion into target regions in the mantle layer (prospective gray matter) of the spinal cord, we examined the interactions between DRG axons and spinal cord. DRG neurons were dissociated from chick embryos and cultured for 1-2 days on cryostat sections of the spinal cord at embryonic day 5 (E5) or at E9. E5 and E9 DRG neurons extended neurites onto both marginal zone (prospective white matter) and mantle layer (prospective gray matter) of the spinal cord, suggesting that both of these regions are permissive for neurite growth. When E5 DRG neurites approached cryosections of E5 spinal cord from outside, most of them ran in the marginal zone without invading the mantle layer. In contrast, about half of E9 DRG neurites entered the mantle layer after crossing the marginal zone of E9 spinal cord. These growth patterns of DRG neurites on spinal marginal zone and mantle layer are similar to the pathway formation of DRG axons at comparable stages in vivo; DRG axons run exclusively in the prospective dorsal funiculus before E6, and enter the mantle layer (prospective dorsal horn) to reach the target regions by E9. Perturbation of functions of Ng-CAM, Nr-CAM, and axonin-1/SC2 by adding the specific antibodies in the culture medium increased the ratio of DRG neurites entering the mantle layer of E5 spinal cord, suggesting that these cell adhesion molecules are involved in keeping DRG neurites in the marginal zone. Taken together with the expression of Ng-CAM, Nr-CAM, and axonin-1/SC2, these CAMs on DRG axons may regulate the guidance of these axons in the marginal zone before E6, and the subsequent decrease in the relative levels of these CAMs might allow DRG axons to invade the target mantle layer.
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Affiliation(s)
- T Shiga
- Department of Anatomy, Yamagata University School of Medicine, Yamagata, 990-23, Japan
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29
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Peles E, Nativ M, Lustig M, Grumet M, Schilling J, Martinez R, Plowman GD, Schlessinger J. Identification of a novel contactin-associated transmembrane receptor with multiple domains implicated in protein-protein interactions. EMBO J 1997; 16:978-88. [PMID: 9118959 PMCID: PMC1169698 DOI: 10.1093/emboj/16.5.978] [Citation(s) in RCA: 345] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Receptor protein tyrosine phosphatase beta (RPTPbeta) expressed on the surface of glial cells binds to the glycosylphosphatidylinositol (GPI)-anchored recognition molecule contactin on neuronal cells leading to neurite outgrowth. We describe the cloning of a novel contactin-associated transmembrane receptor (p190/Caspr) containing a mosaic of domains implicated in protein-protein interactions. The extracellular domain of Caspr contains a neurophilin/coagulation factor homology domain, a region related to fibrinogen beta/gamma, epidermal growth factor-like repeats, neurexin motifs as well as unique PGY repeats found in a molluscan adhesive protein. The cytoplasmic domain of Caspr contains a proline-rich sequence capable of binding to a subclass of SH3 domains of signaling molecules. Caspr and contactin exist as a complex in rat brain and are bound to each other by means of lateral (cis) interactions in the plasma membrane. We propose that Caspr may function as a signaling component of contactin, enabling recruitment and activation of intracellular signaling pathways in neurons. The binding of RPTPbeta to the contactin-Caspr complex could provide a mechanism for cell-cell communication between glial cells and neurons during development.
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Affiliation(s)
- E Peles
- Sugen, Inc., Redwood City, CA 94063, USA
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30
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Sakurai T, Lustig M, Nativ M, Hemperly JJ, Schlessinger J, Peles E, Grumet M. Induction of neurite outgrowth through contactin and Nr-CAM by extracellular regions of glial receptor tyrosine phosphatase beta. J Cell Biol 1997; 136:907-18. [PMID: 9049255 PMCID: PMC2132488 DOI: 10.1083/jcb.136.4.907] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Receptor protein tyrosine phosphatase beta (RPTPbeta) is expressed as soluble and receptor forms with common extracellular regions consisting of a carbonic anhydrase domain (C), a fibronectin type III repeat (F), and a unique region called S. We showed previously that a recombinant Fc fusion protein with the C domain (beta C) binds to contactin and supports neuronal adhesion and neurite growth. As a substrate, betaCFS was less effective in supporting cell adhesion, but it was a more effective promoter of neurite outgrowth than betaCF. betaS had no effect by itself, but it potentiated neurite growth when mixed with betaCF. Neurite outgrowth induced by betaCFS was inhibited by antibodies against Nr-CAM and contactin, and these cell adhesion molecules formed a complex that bound betaCFS. NIH-3T3 cells transfected to express betaCFS on their surfaces induced neuronal differentiation in culture. These results suggest that binding of glial RPTPbeta to the contactin/Nr-CAM complex is important for neurite growth and neuronal differentiation.
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Affiliation(s)
- T Sakurai
- Department of Pharmacology, New York University Medical Center 10016, USA
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31
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Grumet M, Sakurai T, Friedlander D, Lustig M. 39 Modulation of neurite growth by interactions of neural cell adhesion molecules with brain proteoglycans. Int J Dev Neurosci 1996. [DOI: 10.1016/0736-5748(96)80234-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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32
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Abstract
Patients treated with electroconvulsive therapy (ECT) have a more severe illness. This severity is evidenced in the clinical profile of the illness, in the course of the illness, in the resistance to pharmacotherapy, and in the high relapse and recurrence rates after the course of ECT. In this article the authors explore some of the issues, particularly those of biological correlates of severe mood disorders and the continuation of treatment after ECT, which may be factors in this increased severity. The authors propose avenues for the investigation and treatment of severe mood disorders treated with ECT.
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Affiliation(s)
- L Grunhaus
- Psychiatry Division, Sheba Medical Center, Tel Hashomer, Israel
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Abstract
We have characterized the nature and pattern of cell death during regression of the pupillary membrane, a developmentally transient capillary network found in the anterior chamber of the eye. This analysis has revealed that the cellular components of the pupillary membrane include vascular endothelial cells in an intricate network of fine capillaries as well as attendant macrophages. The capillaries are situated on the anterior surface of the lens and held in relative position by a cobweb-like meshwork of extracellular matrix fibres that regress along with the cellular components of this structure. Cell death during regression of the pupillary membrane is characteristic of apoptosis. Specifically, apoptotic bodies containing condensed chromatin can be observed in vascular endothelial cells and genomic DNA isolated from the pupillary membrane shows the nucleosomal fragmentation pattern typical of apoptotic cells. Using a method for labelling fragmented DNA in tissue preparations (TUNEL), we have assessed the overall pattern of apoptotic cell death during pupillary membrane regression. We find that apoptosis occurs either in single cells in healthy vessels or synchronously along the entire length of a capillary segment. Both morphological and TUNEL analysis indicate that capillary regression occurs from junction to junction one segment at a time. We propose a model to explain the pattern of capillary regression observed and conclude from these and previous experiments (Lang and Bishop (1993) Cell 74, 453–462), that during regression of the pupillary membrane, the macrophage elicits target cell death by inducing apoptosis.
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Affiliation(s)
- R Lang
- Skirball Institute for Biomolecular Medicine, Developmental Biology and Genetics, New York University Medical Center, NY 10016
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Kratochvíl L, Lustig M. [History of the so-called Bateman function]. Cesk Farm 1984; 33:210-2. [PMID: 6388865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Kratochvil L, Lustig M. [A slide ruler and nomogram for calculations in cumulation kinetics of cardiac glycosides (author's transl)]. Basic Res Cardiol 1976; 71:160-72. [PMID: 1267742 DOI: 10.1007/bf01927868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
UNLABELLED 1. Substance I, whose elimination we can approximate with an exponential function, is active in the organism. 2. At a given moment substance II with the same onset of action whose elimination we also can approximate with an exponential function but different from substance I, starts to be added at regular intervals. 3. The relative levels of the two substances can be added up. 4. The optimal dose-scheme for the most regular effect is to be sought. RESULTS According to the relations derived in repost (5) published previously a slide ruler and a nomogram are constructed by the authors for that purpose. The scales are described as well as how to work with them. Some examples are included. The slide ruler and the nomogram are suitable for some further calcaulations in cumulation kinetics, which is briefly mentioned. These expedients are mainly meant for the application of cardiac glycosides. The same principle can be used in all cases to which the assumptions mentioned above apply.
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Kratochvíl L, Lustig M. [A contribution to the problem of dosage of cardiac glycosides after a change in glycoside preparation. Mathematical models of optimal dosage (author's transl)]. Basic Res Cardiol 1974; 69:573-84. [PMID: 4451545 DOI: 10.1007/bf01914493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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