Análise ultraestrutural do colágeno de feridas cutâneas de coelhos tratadas com plasma rico em plaquetas de equino / Ultrastructural analysis of the collagen of rabbit skin wounds treated with platelet-rich equine plasma

O colágeno é sintetizado e segregado no espaço extracelular e organizados em fibrilas estriadas de acordo com o tipo de tecido. Utilizaram-se 24 coelhos brancos da raça Nova Zelândia, com idade de 12 meses e com 3,0kg de peso corporal, para avaliar a porcentagem de colágeno das feridas cutâneas tratadas com plasma rico em plaquetas de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A. Os animais foram separados em quatro grupos de igual número e submetidos à remoção de pele na região das linhas médias dorsal torácica (feridas tratadas) e lombar (feridas controle). As feridas torácicas foram tratadas com plasma rico em plaqueta de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A, e as do grupo controle somente com a pomada. Dos animais do grupo I, foi coletado tecido cutâneo, para a avaliação histológica e a ultraestrutural, com três dias de pós-operatório; dos animais do grupo II, com sete dias; do grupo III, com 14 dias; e do grupo IV, com 21 dias. Decorrido o período de avaliação de cada grupo, foi coletado fragmento de pele para avaliação da porcentagem de colágeno, bem como do diâmetro e da densidade da fibrila de colágeno por microscopia eletrônica de transmissão. O tratamento com PRP de equino associado à aplicação tópica da pomada mostrou-se eficaz na maturação das fibrilas colágenas e na antecipação do processo cicatricial.(AU)

Collagen is synthesized and secreted into the extracellular space and organized into striated fibrils according to the tissue type. This study evaluated the concentration of collagen in rabbit skin wounds treated with equine platelet-rich plasma (PRP) and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A. Twenty-four New Zealand white rabbits aged 2 to 12 months and weighing 3.0kg were included. The animals were allocated equally into four groups and the skin was removed from the thoracic dorsal midline (treated wound) and lumbar (control wound) regions. The thoracic wounds were treated with equine PRP and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A, and the control group was treated with the ointment alone. For histological and ultrastructural assessment, cutaneous tissue was collected on postoperative days 3 (group I), 7 (group II), 14 (group III), and 21 (group IV). After the evaluation period, in each group, a skin fragment was collected for analysis of the collagen concentration, as well as the collagen fibril diameter and density by transmission electron microscopy. The results indicated that treatment with equine PRP combined with topical application of the ointment was effective in facilitating the maturation of collagen fibrils and the wound healing process.(AU)

Biomechanical Characteristics of Collagen Fibrils of Human Free Gingival Tissues- Atomic Force Microscope Study

@#The information of biomechanical properties is crucial in the study of biological tissue and its clinical relevance. 3mm x 3mm free gingival human tissues was taken using disposable punch biopsy (Accu sharp blade, India) and stored in 0°C Freezer. The sample was sectioned to a thickness of 10μm using high profile microtome blade (Leica 818, Germany) and cryostat (Leica CM1850UV, United Kingdom). The sample was analysed using Atomic Force Microscope (Nanowizard® 3, JPK Instruments, Germany) at room atmosphere. The collagen fibrils of the free gingival tissues appeared to be stacked in basket weave like structure. The mean value of free gingival collagen fibrils width and the length of D-band were 106.71±11.18nm and 65.82 ± 3.04nm respectively. The Young’s modulus of collagen fibrils for human free gingival tissue at overlap region was 212.88 ± 242.58 MPa, whereas at the gap region was 207.00 ± 230.71 MPa. Within the limitation of the study, the collagen fibrils appeared to be stacked in basket weave-like structure. The length and width of the collagen fibril were similar to the values investigated using other techniques. There was significant linear relationship between Young’s modulus of overlap and gap regions.

Changes of scleral structures and biomechanical properties in the process of sclera post embryonic development / 医用生物力学

Objective To investigate the changes of morphological structures and biomechanical properties of scleral tissues in rabbits at different month ages. Methods The eyeballs of 1, 2 and 3 month-old New Zealand white rabbits were obtained for measuring the diameter and axial length, and the thickness of scleral tissues. Part of the scleral tissues was used to observe scleral structures with HE staining, some other part was used to observe collagen fibrils by electron microscope, and the left part were cut into strips and used to test the elastic modulus of the sclera on Instron 5544 system. Results The diameter, axial length of eyeballs and the thickness of the sclera were increased with month age. The elastic modulus of scleral tissues was also increased with month age. The numbers of scleral fibroblasts were decreased and the numbers of fiber bundles were increased with month age. The diameters of collagen fibrils were increased with month age. Conclusions In the post-embryonic stages, the structures of eyeball and sclera are changed continually, with growing numbers of thicker collagen fibers, and the biomechanical properties of scleral tissues are improved correspondingly. The mechanism of post-embryonic development in sclera is further explained in the study, which can provide theoretical guidance for prevention of sclera-related diseases.

Transmission of mouse senile amyloid fibrils in skeletal muscle / 中国人兽共患病学报

ABSTRACT:Recently ,prion‐like transmission has been found in various amyloidosis .AApoAII amyloid fibrils in mouse senile amyloidosis have exhibited transmissibility .AApoAII amyloid fibrils ,which were excreted from mice and contained in fe‐ces or milk ,cause mouse senile amyloidosis .However ,transmissibility of AApoAII amyloid fibrils through other pathways has not yet been established .In this study ,we injected AApoAII amyloid fibrils into R1 .P1‐A poa2c mice to induce AApoAII sys‐temic amyloidosis .Two months later ,AApoAII amyloid fibrils ,which deposited in the skeletal muscles of amyloid‐affected mice ,were used to induce AApoAII systemic amyloidosis .Mouse senile amyloidosis which deposited in skeletal muscles could induce secondary transmission of AApoAII amyloidosis .The evidence of transmission through skeletal muscles in non‐prion systemic amyloidosis is found in our study .This pathway of transmission provides new insight into the potential for food‐borne pathogenesis and etiology of systemic amyloidosis .

Quantification of left ventricular myocardial collagen system in children, young adults, and the elderly / Cuantificación del sistema de colágeno del ventrículo izquierdo del miocardio en niños, adultos jóvenes y ancianos

Studies on the collagen system of the human myocardium are still limited compared to those on small laboratory animals. The aim of this work was to observe the collagen tissue of the myocardium of the human heart as a function of age. The types of collagen, as well as the density of collagen tissue and the diameter of collagen fibrils, were examined. Fragments of the left ventricular wall from 15 hearts, 5 from children, 5 from young adults, and 5 from elderly individuals, were analyzed by using the Picrosirius-polarization method and by transmission electron microscopy (TEM). The results showed the presence of collagen type III and collagen type I, both in the endomysium and perimysium of the 3 groups studied. Measurements of collagen content in myocardial tissue displayed that both endomysial and perimysial collagen increase in number and thickness in the adult and elderly. These histochemical results coincided with the observations obtained with the electron microscope in showing an increase in the number of collagen fibrils with a large diameter in the adult and elderly hearts. The present results on cardiac collagen may be important for assessing the pathogenesis of several cardiopathies in the hearts of children, young adults, and the elderly.

Los estudios sobre el colágeno del miocardio humano son aún escasos en comparación con los hechos en pequeños animales de laboratorio. El objetivo de este trabajo fue cuantificar el tejido colágeno del miocardio del corazón humano en función de la edad. Se estudiaron los tipos de colágeno, su densidad y el diámetro de las fibrillas de colágeno. Para esto se utilizaron fragmentos de la pared del ventrículo izquierdo de 15 corazones, cinco de niños, cinco de adultos jóvenes y 5 de personas de edad avanzada. Las muestras se analizaron mediante el método de Picrosirius-polarización y por microscopía electrónica de transmisión (MET). Los resultados mostraron la presencia de colágeno tipo III y de tipo I, tanto en el endomisio como en el perimisio de los tres grupos estudiados. Además, aumenta el colágeno tanto en el endomisio como en el perimísio, así como su número y grosor a medida que aumenta la edad. Los resultados histoquímicos coincidieron con las observaciones obtenidas con el microscopio electrónico, en las que se observa un aumento en el número de fibrillas de colágeno de gran diámetro en los corazones de los adultos y los ancianos. Estos resultados podrían ser importantes para la evaluación de la patogénesis de varias cardiopatías en los corazones de niños, jóvenes y ancianos.

Aggregation properties of a short peptide that mediates amyloid fibril formation in model proteins unrelated to disease.

Short peptides have been identified from amyloidogenic proteins that form amyloid fibrils in isolation. The hexapeptide stretch 21DIDLHL26 has been shown to be important in the self-assembly of the Src homology 3 (SH3) domain of p85α subunit of bovine phosphatidylinositol-3-kinase (PI3-SH3). The SH3 domain of chicken brain α- spectrin, which is otherwise non-amyloidogenic, is rendered amyloidogenic if 22EVTMKK27 is replaced by DIDLHL. In this article, we describe the aggregation behaviour of DIDLHL-COOH and DIDLHL-CONH2. Our results indicate that DIDLHL-COOH and DIDLHL-CONH2 aggregate to form spherical structures at pH 5 and 6. At pH 5, in the presence of mica, DIDLHL-CONH2 forms short fibrous structures. The presence of NaCl along with mica results in fibrillar structures. At pH 6, DIDLHL-CONH2 forms largely spherical aggregates. Both the peptides are unstructured in solution but adopt β-conformation on drying. The aggregates formed by DIDLHL-COOH and DIDLHL-CONH2 are formed during drying process and their structures are modulated by the presence of mica and salt. Our study suggests that a peptide need not have intrinsic amyloidogenic propensity to facilitate the selfassembly of the full-length protein. The propensity of peptides to form self-assembled structures that are nonamyloidogenic could be important in potentiating the self-assembly of full-length proteins into amyloid fibrils.

Effects of Mitomycin C on Scleral Collagen Fibrils According to Atomic Force Microscopy

PURPOSE: To investigate the effects of mitomycin C on the scleral collagen surfaces using atomic force microscopy (AFM). METHODS: Two non-contact mode AFM machines were used to observe changes in the morphological characteristics of human scleral surfaces before and after one, three, and five minutes of 0.02% mitomycin C application. Based on AFM topography and deflection images of the collagen fibril, the morphological characteristics of scleral fibrils including the fibril diameter and D-period were measured using the line profile. RESULTS: The sclera collagen fibril treated with 0.02% mitomycin C for one minute did not show any significant increases in mean fibril diameter (155.04 +/- 17.46 nm) or mean D-periodicity (70.02 +/- 3.33 nm), compared to those of the control group. However, the scleral collagen fibrils treated with 0.02% mitomycin C for three and five minutes showed significant increases in mean fibril diameter (182.33 +/- 16.33 nm, 199.20 +/- 12.40 nm, respectively) and mean D-periodicity (70.27 +/- 13.66 nm, 72.75 +/- 19.32 nm, respectively), compared to those of the control group. CONCLUSIONS: The present study examined the structural changes in the scleral collagen fibrils before and after mitomycin C application according to atomic force microscopy. The results indirectly suggest that three or more minutes of 0.02% mitomycin C application affects the morphology of scleral collagen.

Structural insight to mutated Y116S transthyretin by molecular dynamics simulation.

Familial amyloidotic polyneuropathy (FAP) is strictly associated with point mutations of transthyretin (TTR) protein. The Tyr116->Ser (Y116S) mutant TTR is an important amyloidogenic variant responsible for FAP. Structural dynamics of monomeric TTR and its mutant (Y116S) may give some clue relating to amyloid formation. In this study, molecular dynamic simulation at 310 K has been performed on wild-type and mutant (Y116S) TTR monomer, which can provide the molecular insight of structural transition in the inner and outer strand of the protein. Results show that mutation in the H-strand (Tyr116->Ser) leads to disruption of secondary structure and H-bonding pattern of some important parts of the inner DAGH-sheet of the protein. Especially, the residues T106, A108, L110 of G-strand, S117 and T119 of H-strand are affected, which are involved in the binding of thyroxin hormone. This unfolding of mutant structure during dynamics may cause instability in the protein and thus induce amyloidgenesis.

Morphological features of Cyclosprin A-induced Gingival Hyperplasia / 대한치주과학회지

Cyclosporin A(CsA) is now widely used to treat organ transplant recipients. But CsA has various short-and long-term side effects. Especially, gingival hyperplasia is not easy to resolve since its nature is still unknown. This study discusses the pathogenesis of CsA-induced gingival hyperplasia on the basis of data obtained from light and electron microscopic studies of biopsis from patients on CsA treatment after kidney transplantation. Light microscopically, the multilayered squamous epithelium showed an irregular surface of parakeratosis and deep invaginations in the subepithelial tissue. At lamina propria, we observed bundles of irregularly arranged collagen fiber, some fibroblasts, numerous capillary vessels and a large diffuse infiltration of plasma cells. Ultrastructurally, many fibroblasts, collagen fibers, collagen fibrils were present in lamina propria. On the basis of the data collected, we propose that the morphological features of the dimensional increase in gingival tissue associated with CsA treatment in kidney transplant patients may be considered proliferative fibroblasts, collagen fibers, collagen fibrils in lamina propria.

Scanning Electron Microscopic Observation on Bone Auto-Graft in Cranium / 上海第二医科大学学报

ObjectiveTo study absorbed mechanism of free bone auto-graft in cranium.MethodsTwenty-four adult New Zealand rabbits were randomly divided into two groups of twelve each. Cranium graft or rib graft was implanted on each side of the cranium. The onlay graft was harvested at the 12th and 24th week, and the collagen fibers were scrutinized under scanning electron microscope. ResultsThe number of the bone collagen fibrils at twenty- fourth week was more than that of the twelfth week, the arrangement of collagen fibrils at the twenty- fourth week was more regular than that of the twelfth week, and the collagen fibrils of the cranium graft were more numberous and regular than those of the rib graft observed at the twelfth week, but they were similar at twenty - fourth week. ConclusionRemoding time of cranium graft is shorter than that of rib graft, but bone remoding of both cranium and rib has finished in 24th week after operated.

Ultrastructual analysis of the fibrous layer of condyle in the rat temporomandibular joint with ageing

Primary Systemic Amyloidosis involved the Conjunctiva

Amyloid may involve the conjunctiva without deposits of the skin of the eyelid in primary localized amyloidosis, but extremely rare in primary systemic amyloidosis. We describe the clinicopathologic features of a case of primary systemic amyloidosis which invloved the conjunctiva and larynx. A 58-years-old woman presented a conjuctival mass of the left eye. Slit lamp microscopy showed a pinkish, flat elevated mass on the bulbar conjunctiva, fornix, and upper tarsal conjunctiva. There was no history of antecedent ocular or systemic diseases. She had undergone total laryngectomy for laryngeal amyloidosis. Microscopically, a pale amorphous eosinophilic material was deposited in the subcojunctival tissue. The deposit showed metachromasia with crystal violet, and dichroism and birefringence in polarized light following Congo red staining. Electron microscopically amyloid was comprised of linear add non-branching fibrils, which were about 11nm in width.

THE MORPHOLOGICAL OBSERVATIONS AND BONE HISTOMOPHOMETRIC STUDY OF THE CHICKEN EMBRYO FEMUR IN EXPERIMENTAL FLUOROSIS / 解剖学报

The femur of chicken embryo in experimental fluorosis was observed under light and electron microscope, and studied by bone histomorphometric method. The results showed that most of osteoblasts were cuboid and crowded together on the surface of bone trabecula in experimental group. The osteoid was increased and mineralized bone was diminished. The bone reformation indexes were higher significantly and the bone resorption indexes did not show differences between the two groups. The cross striations of type Ⅰ collagen fibrils in osteoid layers of experimental group were indistinct and bone lamella were jumble array. Our results suggest that though fluoride has a stimulating action on the embryonic osteoblasts and enhanced the bone formation, the osteoblasts produced abnormal collagen fibrils which caused disorder of osteoid mineralization and led to osteomalacia.