In maxillofacial surgery, there is a significant need for the design and fabrication of porous scaffolds with customizable bionic structures and mechanical properties suitable for bone tissue engineering. In this paper, we characterize the porous Ti6Al4V implant, which is one of the most promising and attractive biomedical applications due to the similarity of its modulus to human bones. We describe the mechanical properties of this implant, which we suggest is capable of providing important biological functions for bone tissue regeneration. We characterize a novel bionic design and fabrication process for porous implants. A design concept of "reducing dimensions and designing layer by layer" was used to construct layered slice and rod-connected mesh structure (LSRCMS) implants. Porous LSRCMS implants with different parameters and porosities were fabricated by selective laser melting (SLM). Printed samples were evaluated by microstructure characterization, specific mechanical properties were analyzed by mechanical tests, and finite element analysis was used to digitally calculate the stress characteristics of the LSRCMS under loading forces. Our results show that the samples fabricated by SLM had good structure printing quality with reasonable pore sizes. The porosity, pore size, and strut thickness of manufactured samples ranged from (60.95± 0.27)% to (81.23±0.32)%, (480±28) to (685±31) μm, and (263±28) to (265±28) μm, respectively. The compression results show that the Young's modulus and the yield strength ranged from (2.23±0.03) to (6.36±0.06) GPa and (21.36±0.42) to (122.85±3.85) MPa, respectively. We also show that the Young's modulus and yield strength of the LSRCMS samples can be predicted by the Gibson-Ashby model. Further, we prove the structural stability of our novel design by finite element analysis. Our results illustrate that our novel SLM-fabricated porous Ti6Al4V scaffolds based on an LSRCMS are a promising material for bone implants, and are potentially applicable to the field of bone defect repair.
Alloys ; Bionics ; Bone Substitutes/chemistry* ; Bone and Bones/pathology* ; Compressive Strength ; Elastic Modulus ; Finite Element Analysis ; Humans ; Lasers ; Materials Testing ; Maxillofacial Prosthesis Implantation ; Porosity ; Pressure ; Printing, Three-Dimensional ; Prostheses and Implants ; Prosthesis Design ; Stress, Mechanical ; Surgery, Oral/instrumentation* ; Tissue Engineering/methods* ; Titanium/chemistry*

STUDY DESIGN: Histopathological analyses were performed in ligamentum flavum (LF) hypertrophy patients with lumbar spinal stenosis (LSS) and lumbar disc herniation (LDH). PURPOSE: The aim of the present study was to evaluate histopathological changes in LF patients with LSS and LDH. OVERVIEW OF LITERATURE: LSS is the most common spinal disorder in elderly patients. This condition causes lower back and leg pain and paresis, and occurs as a result of degenerative changes in the lumbar spine, including bulging of the intervertebral discs, bony proliferation of the facet joints, and LF thickening; among these, LF thickening is considered a major contributor to the development of LSS. METHODS: A total of 71 patients operated with the surgical indications of LSS and LDH were included. LF samples were obtained from 31 patients who underwent decompressive laminectomy for symptomatic degenerative LSS (stenotic group) and from 40 patients who underwent lumbar discectomy for LDH (discectomy group). LF materials were examined histopathologically, and other specimens were examined for collagen content, elastic fiber number and array, and presence of calcification. RESULTS: The stenotic and discectomy groups did not differ with regard to mean collagen concentration or mean elastic fiber number (p=0.430 and p=0.457, respectively). Mean elastic fiber alignment was 2.36±0.99 in the stenotic group and 1.38±0.54 in the discectomy group (p<0.001). Mean calcification was 0.39±0.50 in the stenotic group, whereas calcification was not detected (0.00±0.00) in the discectomy group; a statistically significant difference was detected (p<0.001) between groups. CONCLUSIONS: LF hypertrophy in spinal stenosis may occur as a result of elastic fiber misalignment along with the development of calcification over time. Further studies determining the pathogenesis of LSS are needed.
Aged ; Collagen ; Diskectomy ; Elastic Tissue ; Humans ; Hypertrophy ; Intervertebral Disc ; Laminectomy ; Leg ; Ligamentum Flavum* ; Paresis ; Pathology ; Spinal Stenosis* ; Spine ; Zygapophyseal Joint

Elastic Tissue ; pathology ; Humans ; Lung Neoplasms ; diagnosis ; Pleura ; pathology ; Staining and Labeling

Hereditary sclerosing poikiloderma (HSP) is a very rare disease. The clinical features are principally widespread poikiloderma and linear hyperkeratotic and sclerotic bands. We report an 18-yr-old male who presented reticular hyperpigmented lesions on the trunk and extremities since 2-yr-old. Also, linear sclerosing bands appeared on both antecubital and popliteal fossae after yr. Histopathologic finding showed dense sclerotic collagen fibers with telangiectasia in the upper dermis and fragmentations of damaged elastic fibers in the elastic stain, consistent with HSP. We report the first Korean case of HSP.
Abnormalities, Multiple ; Adolescent ; Elastic Tissue/pathology ; Fingers/abnormalities ; Humans ; Hyperpigmentation/pathology ; Male ; Micrognathism/pathology ; Rothmund-Thomson Syndrome/*diagnosis/pathology ; Sclerosis/pathology ; Skin Diseases/diagnosis/pathology

OBJECTIVE: To explore the postmortem changes of biomechanical properties of underwater corpses and value for estimating postmortem interval. METHODS: SD rats were sacrificed by cervical vertebra dislocation and stored in the water at constant temperature. The vessel wall, skin, muscle, small intestine and colon were sampled at different postmortem time points (0h, 6h, 12h, 18h, 24h, 30h, 36h, 42h, 48h, 60h, 72h, 96h, 120h, 144h, 168h, 192h). The biomechanics properties of different soft tissues including ultimate load, strain, maximum stress were measured by electronic universal material testing machine. RESULTS: Except for the vessel wall, the biomechanics properties of skin, muscle, small intestine and colon showed linear decrease gradually after death. Each tissue displayed its obvious "window period" for PMI estimation. CONCLUSION The time-sequential changes of biomechanical property parameters of soft tissue in underwater corpses are significantly correlated with PMI and it could be a simple and quantitive new technology for estimating PMI. The specific heat capacity of the heat-eliminating medium around the corpses probably is one of the physical factors to influence algor mortis, autolysis, putrefaction and biomechanics properties.
Animals ; Biomechanical Phenomena ; Cadaver ; Elastic Tissue/physiology* ; Forensic Pathology/methods* ; Intestines ; Male ; Muscles ; Postmortem Changes ; Rats ; Rats, Sprague-Dawley ; Skin ; Stress, Mechanical ; Time Factors ; Weight-Bearing

OBJECTIVETo investigate the relationship between the extracellular matrix (ECM) and neoplastic progression in hamster with tongue cancer.

METHODSForty-eight specimens of hamster tongue cancer were divided into control group (n=6) and experimental group (n=42). The pathological grade of the specimens was assessed (including 3 stages, namely atypical hyperplasia, carcinoma in situ and early invasive carcinoma). The sections of the tongue were stained with Masson and aldehyde-fuchsin (AF) staining for microscopic observation of the elastic fiber and collagen fiber changes.

RESULTSWithin the connective tissue cores (CTC) of the papillae in the control group was a framework of numerous and fine Gomrori's aldehyde fuchsin-positive elastic fibers. But in the stages of dysplasia and carcinoma in situ, these elastic fibers decreased and further diminished in the CTC in early invasive carcinoma. In dysplasia and carcinoma in situ stages, most of the elastic fibers collapsed with scattered elastic fibers, and the elastic fibers decreased significantly in early invasive carcinoma. The control group showed a significantly greater number of elastic fibers in the experimental group. The collagen fiber was obviously increased and irregularly arranged in dysplasia and carcinoma in situ stage; in early invasive carcinoma, the collagen fibers became thicker with deposition in the lamina propria.

CONCLUSIONAn excessive deposition of collagen fiber and reduction of the elastic fibers is an important factor contributing to the development of tongue carcinoma in hamsters.

Animals ; Carcinoma ; pathology ; Collagen ; metabolism ; Connective Tissue ; pathology ; Cricetinae ; Elastic Tissue ; pathology ; Extracellular Matrix ; pathology ; Neoplasms, Experimental ; pathology ; Tongue Neoplasms ; pathology

OBJECTIVETo investigate the pathological characters and the corresponding clinical significance of internal hemorrhoids tissues.

METHODSNormal anal cushion and internal haemorrhoids tissue samples were obtained after stapled haemorrhoidectomy procedure from 24 grade III hemorrhoidal patients. The macroscopically normal cushions served as own controls and the normal cushions from a patient without a history of haemorrhoids as quality control. Routine Hematoxylin-Eosin and orcein were performed for elastic fibers.

RESULTSCompared with the corresponding normal anal cushions, the subepithelial vessels especially the cavernous vessels of the hemorrhoidal tissues showed obvious structural impair, retrograde changes, and the internal elastic lamina were ruptured and discontinuous. In addition, thrombosis and subsequent ischemic changes were observed. The Trietz's muscle and the fibro-elastic tissues showed hypertrophy, distortion, rupture and tortility. Obvious mucosal injury was observed in the mucous of hemorrhoidal tissues. Venous dilatation was infrequent in the hemorrhoidal tissues.

CONCLUSIONSThe anal cushions of hemorrhoids disease patients show significant pathological changes. The pathological changes include structural impair, retrograde changes of the cavernous vessels and the hypertrophy, distortion, rupture and tortility of the Trietz's muscle and the fibroelastic tissues, and mucosal injury of the mucous membranes. These pathological changes are the basis of pathogenesis and development of hemorrhoids.

Adult ; Anal Canal ; pathology ; Elastic Tissue ; pathology ; Hemorrhoids ; pathology ; surgery ; Humans ; Middle Aged

OBJECTIVETo investigate the pathological variations in internal hemorrhoid and evaluate the expression of nitric- oxide synthase(NOS),vascular endothelial growth factor(VEGF),matrix metalloproteinase- 2(MMP2) and MMP9.

METHODSNormal anal cushion and internal hemorrhoids tissue samples were obtained from 24 patients with iii degree hemorrhoids after procedure for prolapse and hemorrhoids(PPH) procedure. The expression of NOS, VEGF, MMP2, MMP9 and CD34 were detected by immunohistochemical staining; the microvessel density (MVD) was counted by anti- CD34 antibody; the elastic fibers were detected by orcein staining.

RESULTSThere were statistically significant differences in the expression of MVD, VEGF, MMP9 between internal hemorrhoid tissue and normal anal cushions(P< 0.05). iNOS was significantly increased in hemorrhoid tissue, but no significant difference between normal anal cushions and hemorrhoid tissue. Morphological abnormalities such as breaking, distortion, mortality, hyaline degeneration were found in elastic fibers of internal hemorrhoid tissue, but not in normal anal cushions.

CONCLUSIONAngiogenesis is evident in hemorrhoid tissue, suggesting the possible mechanism in the pathogenesis of hemorrhoids. The direct degeneration effect of MMP9 on supporting structure elastic fibers in anal cushion is another important mechanism. The high expression of iNOS suggests the inflammatory factors involve in the pathogenesis of hemorrhoids, and NO may be involve in pathological effect on hemorrhoids.

Adult ; Elastic Tissue ; metabolism ; pathology ; Hemorrhoids ; metabolism ; pathology ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Microvessels ; pathology ; Middle Aged ; Neovascularization, Pathologic ; pathology ; Nitric Oxide Synthase ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

BACKGROUND: Over the years many possible explanations for the development of varicose vein have been suggested. The main possible mechanisms are a valvular failure theory and a weak wall theory. However, the definite cause of varicose has not been determined yet. OBJECTIVE: The aims of this study are to observe the pathologic changes in the smooth muscle cells and extracellular matrix of the primary varicose vein. An understanding of the pathology may possibly help to understand the pathogenesis of varicose veins. METHODS: A total of 20 vein specimens of primary varicose vein were collected from 13 patients who underwent ambulatory phlebectomy. Among them, 16 specimens were thick segments and 4 specimens were thin segments of varicose veins. Control samples were collected from two patients with no history and clinical evidence of varicose vein. Each specimen was examined with a JEM 1200EX-II electron microscopy. Ultrastructural findings between thick and thin segments of varicose veins and normal veins were also compared semiquantitatively. RESULTS: The smooth muscle cells of varicose veins were abnormal in shape and lost their fusiform appearance with many vacuoles. Increased extracellular matrix shows the increase of degenerated collagen fibers and decrease of elastic fibers. Thin segments revealed more atrophic smooth muscle cells and phagocytosis than thickened segments. Thick segments showed increased collagen fiber. CONCLUSION: These ultrastructural changes may be not the primary cause of varicose veins but the secondary remodeling processes of vein walls by hemodynamic stress.
Collagen ; Elastic Tissue ; Extracellular Matrix ; Hemodynamics ; Humans ; Leg* ; Microscopy, Electron ; Myocytes, Smooth Muscle ; Pathology ; Phagocytosis ; Vacuoles ; Varicose Veins* ; Veins

BACKGROUND AND OBJECTIVES: Detailed information on how an epithelial differentiation and elastic structures occurred in the developing eustachian tube would be helpful in understanding both normal physiology and pathology of the tubotympanum. This study was undertaken to establish elastic structures such as cartilage, elastic fiber, and collagen fiber in the embryonic mouse eustachian tube at a stage when epithelial differentiation is taking place. MATERIALS AND METHOD: Thirty four mice (BALB/c mouse), aged from gestational day 11 to postnatal day 21, were investigated using Verhoeff stain, Masson trichrome stain and alpha-1 antitrypsin immunohistochemistry. RESULTS: The cartilage-like structures were first found after birth, however, matured cartilages appeared at postnatal day 7. The elastic fibers and collagen fibers surrounding cartilage were abundantly found about 5 days after birth. alpha-1 antitrypsin, which is an strong inhibitor of elastase, began to be immunolabelled at gestational day 16. Its expression has been significantly increased after birth. CONCLUSION: Although the epithelial differentiation and maturation in eustachian tube occured at late embryonal stage, the elastic structures have developed and matured after birth. These findings might be a explanation to why young children are highly susceptible to otitis media.
Animals ; Cartilage ; Child ; Collagen ; Elastic Cartilage ; Elastic Tissue ; Elasticity ; Eustachian Tube* ; Humans ; Immunohistochemistry ; Mice ; Otitis Media ; Pancreatic Elastase ; Parturition ; Pathology ; Physiology