BACKGROUND: We previously demonstrated that continuous exposure to nitrous acid gas (HONO) for 4 weeks, at a concentration of 3.6 parts per million (ppm), induced pulmonary emphysema-like alterations in guinea pigs. In addition, we found that HONO affected asthma symptoms, based on the measurement of respiratory function in rats exposed to 5.8 ppm HONO. This study aimed to investigate the dose-response effects of HONO exposure on the histopathological alterations in the respiratory tract of guinea pigs to determine the lowest observed adverse effect level (LOAEL) of HONO. METHODS: We continuously exposed male Hartley guinea pigs (n = 5) to four different concentrations of HONO (0.0, 0.1, 0.4, and 1.7 ppm) for 4 weeks (24 h/day). We performed histopathological analysis by observing lung tissue samples. We examined samples from three guinea pigs in each group under a light microscope and measured the alveolar mean linear intercept (Lm) and the thickness of the bronchial smooth muscle layer. We further examined samples from two guinea pigs in each group under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). RESULTS: We observed the following dose-dependent changes: pulmonary emphysema-like alterations in the centriacinar regions of alveolar ducts, significant increase in Lm in the 1.7 ppm HONO-exposure group, tendency for hyperplasia and pseudostratification of bronchial epithelial cells, and extension of the bronchial epithelial cells and smooth muscle cells in the alveolar duct regions. CONCLUSIONS These histopathological findings suggest that the LOAEL of HONO is < 0.1 ppm.
Alveolar Epithelial Cells ; drug effects ; Animals ; Bronchi ; drug effects ; Dose-Response Relationship, Drug ; Emphysema ; chemically induced ; Epithelial Cells ; drug effects ; Guinea Pigs ; Hyperplasia ; chemically induced ; Inhalation Exposure ; adverse effects ; Lung ; drug effects ; pathology ; ultrastructure ; Male ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Myocytes, Smooth Muscle ; drug effects ; Nitrous Acid ; toxicity

OBJECTIVES: The emergence of resistant bacteria is being increasingly reported around the world, potentially threatening millions of lives. Amongst resistant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) is the most challenging to treat. This is due to emergent MRSA strains and less effective traditional antibiotic therapies to Staphylococcal infections. The use of bacteriophages (phages) against MRSA is a new, potential alternate therapy. In this study, morphology, genetic and protein structure of lytic phages against MRSA have been analysed. METHODS: Isolation of livestock and sewage bacteriophages were performed using 0.4 μm membrane filters. Plaque assays were used to determine phage quantification by double layer agar method. Pure plaques were then amplified for further characterization. Sulfate-polyacrylamide gel electrophoresis and random amplification of polymorphic DNA were run for protein evaluation, and genotyping respectively. Transmission electron microscope was also used to detect the structure and taxonomic classification of phage visually. RESULTS: Head and tail morphology of bacteriophages against MRSA were identified by transmission electron microscopy and assigned to the Siphoviridae family and the Caudovirales order. CONCLUSION: Bacteriophages are the most abundant microorganism on Earth and coexist with the bacterial population. They can destroy bacterial cells successfully and effectively. They cannot enter mammalian cells which saves the eukaryotic cells from lytic phage activity. In conclusion, phage therapy may have many potential applications in microbiology and human medicine with no side effect on eukaryotic cells.
Agar ; Bacteria ; Bacteriophages ; Caudovirales ; Classification ; DNA ; Electrophoresis ; Eukaryotic Cells ; Head ; Humans ; Livestock ; Membranes ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Methods ; Microscopy, Electron, Scanning Transmission ; Microscopy, Electron, Transmission ; Sewage ; Siphoviridae ; Staphylococcal Infections ; Tail

In the present study, rutile phase titanium dioxide nanoparticles (R-TiO₂ NPs) were prepared by hydrolysis of titanium tetrachloride in an aqueous solution followed by calcination at 900℃. The composition of R-TiO₂ NPs was determined by the analysis of X-ray diffraction data, and the characteristic features of R-TiO₂ NPs such as the surface functional group, particle size, shape, surface topography, and morphological behavior were analyzed by Fourier-transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering, and zeta potential measurements. The average size of the prepared R-TiO₂ NPs was 76 nm, the surface area was 19 m²/g, zeta potential was −20.8 mV, and average hydrodynamic diameter in dimethyl sulfoxide (DMSO)–H₂O solution was 550 nm. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and morphological observations revealed that R-TiO₂ NPs were cytocompatible with oral cancer cells, with no inhibition of cell growth and proliferation. This suggests the efficacy of R-TiO₂ NPs for the aesthetic white pigmentation of teeth.
Dimethyl Sulfoxide ; Dynamic Light Scattering ; Hydrodynamics ; Hydrolysis ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Mouth Neoplasms ; Nanoparticles ; Particle Size ; Pigmentation ; Spectrometry, X-Ray Emission ; Spectrum Analysis ; Titanium ; Tooth ; X-Ray Diffraction

BACKGROUND: Nano-hydroxyapatite/polyamide 66 (nHA/PA66) is a composite used widely in the repair of bone defects. However, this material is insufficient bioactivity. In contrast, D-RADA16-RGD self-assembling peptide (D-RADA16-RGD sequence containing all D-amino acids is Ac-RADARADARADARADARGDS-CONH2) shows admirable bioactivity for both cell culture and bone regeneration. Here, we describe the fabrication of a favorable biomaterial material (nHA/PA66/D-RADA16-RGD). METHODS: Proteinase K and circular dichroism spectroscopy were employed to test the stability and secondary structural properties of peptide D-RADA16-RGD respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the surface of these materials. Confocal laser scanning (CLS), cell counting kit-8 tests (CCK-8), alizarin red S staining, cell immunofluorescence analysis and Western blotting were involved in vitro. Also biosafety and bioactivity of them have been evaluated in vivo. RESULTS: Proteinase K and circular dichroism spectroscopy demonstrated that D-RADA16-RGD in nHA/PA66 was able to form stable-sheet secondary structure. SEM and TEM showed that the D-RADA16-RGD material was 7–33 nm in width and 130–600 nm in length, and the interwoven pore size ranged from 40 to 200 nm. CLS suggests that cells in nHA/PA66/D-RADA16-RGD group were linked to adjacent cells with more actin filaments. CCK-8 analysis showed that nHA/PA66/D-RADA16-RGD revealed good biocompatibility. The results of Alizarin-red S staining and Western blotting as well as vivo osteogenesis suggest nHA/PA66/D-RADA16-RGD exhibits better bioactivity. CONCLUSION: This study demonstrates that our nHA/PA66/D-RADA16-RGD composite exhibits reasonable mechanical properties, biocompatibility and bioactivity with promotion of bone formation.
Actin Cytoskeleton ; Blotting, Western ; Bone Regeneration ; Cell Count ; Cell Culture Techniques ; Circular Dichroism ; Endopeptidase K ; Fluorescent Antibody Technique ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Osteogenesis ; Sincalide ; Spectrum Analysis

To prepare AS1411 targeted nano-ultrasonic contrast agent with liquid core, and to evaluate its ability for ultrasonic contrast enhancement and targeting MCF-7 cell in vitro.
 Methods: The modified solvent evaporation, self-synthesized membrane material and perfluorobrominane (PFOB) was used to form nano-ultrasonic contrast agent with PFOB core (nanoparticles, NP); then N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide (EDC/NHS) catalysis was used to connect AS1411 to the surface of NP to prepare NP-AS1411. The transmission electron microscopy was chosen to check the morphology of NP-AS1411. The size, surface charge, encapsulation efficiency, biocompatibility, the contrast grey value and the stability of NP-AS1411 and NP were compared. Whether AS411 was attached to the surface of NP was checked by gel electrophoresis. Fluorescence microscopy and flow cytometry were performed to examine the targeting ability of AS1411.
 Results: NP-AS1411 was a shell-nuclear structure under the electron microscope. Its size was at (245.4±16.5) nm, which was larger than that of NP (P=0.05). There was no significant difference in surface charge and encapsulation efficiency between NP-AS1411 and NP (P>0.05). In the MTT experiment, the cell viability decreased significantly at high concentration of NP-AS411 (25 mg/mL) after incubation for 24 h compared with the control group (0 mg/mL ) (P<0.05). The contrast gray value of NP-AS1411 was at 86.1+ 6.7, which was significantly higher than that of deionized water (P<0.05), and equivalent to that of NP (P>0.05). The contrast grey value of AS1411-NP was 80.1±9.2 after keeping at room temperature for 24 h, which showed no obviously change comparing with that before the treatment (P>0.05). The size of NP-AS1411didn't change too (P>0.05). The results of gel electrophoresis demonstrated that the AS1411 connecting to the surface of NP was the most when the molar ratio of NP:AS1411 was at 40:1. Flow cytometry analysis confirmed that NP and NP-AS1411 were combined with MCF-7 cells separately but the fluorescence produced by the combination of NP-AS1411 and MCF-7 was more intense.
 Conclusion: The modified solvent evaporation and EDC/NHS catalysis could successfully prepare ultrasound contrast agents with aptamer-conjugated nanoparticles with liquid core. The targeted ultrasonic contrast agents with liquid core possess good ultrasonic contrast enhancement ability in vitro, stability and specificity as well.
Cell Survival ; Contrast Media ; chemical synthesis ; Fluorocarbons ; Humans ; MCF-7 Cells ; Microscopy, Electron, Scanning Transmission ; Nanoparticles ; chemistry ; ultrastructure ; Oligodeoxyribonucleotides ; chemical synthesis

BACKGROUNDCoronary microembolization (CME) has been frequently seen in acute coronary syndromes and percutaneous coronary intervention. Small animal models are required for further studies of CME related to severe prognosis. This study aimed to explore a new mouse model of CME.

METHODSThe mouse model of CME was established by injecting polystyrene microspheres into the left ventricular chamber during 15-s occlusion of the ascending aorta. Based on the average diameter and dosage used, 30 C57BL/6 male mice were randomly divided into five groups (n = 6 in each): 9 μm/500,000, 9 μm/800,000, 17 μm/200,000, 17 μm/500,000, and sham groups. The postoperative survival and performance of the mice were recorded. The mice were sacrificed 3 or 10 days after the surgery. The heart tissues were harvested for hematoxylin and eosin staining and Masson trichrome staining to compare the extent of inflammatory cellular infiltration and fibrin deposition among groups and for scanning transmission electron microscopic examinations to see the ultrastructural changes after CME.

RESULTSSurvival analysis demonstrated that the cumulative survival rate of the 17 μm/500,000 group was significantly lower than that of the sham group (0/6 vs. 6/6, P = 0.001). The cumulative survival rate of the 17 μm/200,000 group was lower than those of the sham and 9 μm groups with no statistical difference (cumulative survival rate of the 17 μm/200,000, 9 μm/800,000, 9 μm/500,000, and sham groups was 4/6, 5/6, 6/6, and 6/6, respectively). The pathological alterations were similar between the 9 μm/500,000 and 9 μm/800,000 groups. The extent of inflammatory cellular infiltration and fibrin deposition was more severe in the 17 μm/200,000 group than in the 9 μm/500,000 and 9 μm/800,000 groups 3 and 10 days after the surgery. Scanning transmission electron microscopic examinations revealed platelet aggregation and adhesion, microthrombi formation, and changes in cardiomyocytes.

CONCLUSIONThe injection of 500,000 polystyrene microspheres at an average diameter of 9 μm is proved to be appropriate for the mouse model of CME based on the general conditions, postoperative survival rates, and pathological changes.

Animals ; Brain ; pathology ; Coronary Occlusion ; pathology ; surgery ; Coronary Vessels ; pathology ; surgery ; ultrastructure ; Disease Models, Animal ; Embolization, Therapeutic ; Kidney ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Microscopy, Electron, Scanning Transmission ; Myocardium ; pathology ; Platelet Aggregation ; physiology

This study was carried out to explore the effect of DNA hypomethylation on chondrocytes phenotype, in particular the effect on chondrocyte hypertrophy, maturation, and apoptosis. Chondrocytes derived from caudal region of day 17 embryonic chick sterna were pretreated with hypomethylating drug 5-aza-2'-deoxycytidine for 48 hours and then maintained in the normal culture medium for up to 14 days. Histological studies showed distinct morphological changes occurred in the pretreated cultures when compared to the control cultures. The pretreated chondrocytes after 7 days in culture became bigger in size and acquired more flattened fibroblastic phenotype as well as a loss of cartilage specific extracellular matrix. Scanning electron microscopy at day 7 showed chondrocytes to have increased in cell volume and at day 14 in culture the extracellular matrix of the pretreated cultures showed regular fibrillar structure heavily embedded with matrix vesicles, which is the characteristic feature of chondrocyte hypertrophy. Transmission electron microscopic studies indicated the terminal fate of the hypertrophic cells in culture. The pretreated chondrocytes grown for 14 days in culture showed two types of cells: dark cells which had condense chromatin in dark patches and dark cytoplasm. The other light chondrocytes appeared to be heavily loaded with endoplasmic reticulum indicative of very active protein and secretory activity; their cytoplasm had large vacuoles and disintegrating cytoplasm. The biosynthetic profile showed that the pretreated cultures were actively synthesizing and secreting type X collagen and alkaline phosphatase as a major biosynthetic product.
Alkaline Phosphatase ; Apoptosis ; Cartilage ; Cell Size ; Chondrocytes* ; Chromatin ; Collagen Type X ; Cytoplasm ; DNA ; Endoplasmic Reticulum ; Endoplasmic Reticulum, Rough ; Extracellular Matrix ; Fibroblasts ; Hypertrophy* ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Phenotype ; Vacuoles

OBJECTIVE: To observe the morphological differences between normal uncinate process(UP) mucosa and inferior turbinate mucosa, and explore the physiology function of the UP with the electron microscope. METHOD: The experiment chose 12 patients who have taken nasal endoscopic surgeries(8 cases for normal UP, 4 cases for normal inferior turbinate mucosa). During the surgery, take the mucosa upwards on the filter paper and immediately use scanning electron microscopy and transmission electron microscopy specimens for standard sample preparation methods. Observe the cilia shape, structure and the distribution and the swing direction. RESULT: (1)The internal side and the external side of UP mucosa and inferior turbinate mucosa are all pseudostratified ciliated columnar epithelium, the shapes of cilia are classic "9+2" structures. The distribution of cilia on internal and external lateral of UP and inferior turbinate mucosa are in high density. (2)The direction of cilia on normal inferior turbinate mucosa are generally swing to up and backwards; the cilia on internal lateral of the UP generally swing towards inner side, down and backwards; the cilia on external lateral of the UP generally swing towards down and backwards. CONCLUSION The cilia on internal side and the external side of UP mucosa and inferior turbinate mucosa are in the same structure and shape, but the swing direction of cilia have their own characteristics. It can be concluded that the internal and external lateral of UP may have different functions in nasal sinuses mucus cilia clearance system.
Cilia ; ultrastructure ; Endoscopy ; Epithelium ; ultrastructure ; Humans ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Nasal Mucosa ; ultrastructure ; Nasal Surgical Procedures ; Paranasal Sinuses ; Turbinates ; ultrastructure

OBJECTIVE: To observe the biological characteristics of the human olfactory mucosa mesenchymal stem cells (hOM-MSCs). METHODS: The hOM-MSCs were isolated, cultured and identified in vitro. Scanning electron microscope and transmission electron microscope were used to observe the ultrastructure of hOMMSCs. Th e cells were induced towards adipocyte, osteocyte, neural stem cells, neural-like-cells in vitro. RESULTS: The hOM-MSCs were mainly in spindle shape, arranged with radial colony. The hOMMSCs expressed CD73 and CD90 but no CD34 and CD45. Th e short and thick microvilli processes were seen at the surface of hOM-MSCs by scanning electron microscope, and 2 different cellular morphology of hOM-MSCs were seen under transmission electron microscope. Moreover, the hOMMSCs could be differentiated into adipocyte, osteocyte, neural stem cells and neural cells. CONCLUSION The hOM-MSCs possess general biological characteristics of MSCs and display multiple differentiation functions. They can be served as ideal seed cells in tissue-engineering for injury repair.
Cell Differentiation ; Cells, Cultured ; Humans ; Mesenchymal Stem Cells ; cytology ; ultrastructure ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Olfactory Mucosa ; cytology

Smoking has been positively associated with hearing loss in human. However, its effect on the cochlea has not been previously evaluated. Aim of work is to investigate the effect of nicotine, which is the primary pharmacological component of tobacco, on the structure of the cochlea of adult male guinea pigs. Fifteen male guinea pigs were classified into two groups: group I (control) and group II (nicotine treated group). Group II was further subdivided into two subgroups; IIA and IIB according to the dose of nicotine (3 mg/kg and 6 mg/kg, respectively). The cochlea was harvested and processed for light microscopy, transmission electron microscopy and scanning electron microscopy. Nicotine administration induced damage of outer hair cells which were distorted in shape with vacuolated cytoplasm and heterochromatic nuclei. Topography revealed damage of the stereocilia which included disorganization, bent and limp or complete loss and expansion of the surrounding supporting cells. These changes were more pronounced in the basal turn of the cochlea and mainly involved the outer hair cells. High dose induced more damage and resulted in protrusion of the apical poles of hair cells (blebing), particularly the outer two rows. Nicotine is proved to be harmful to the cells of the cochlea, particularly the outer hair cells of the basal turn. High doses induce blebing of hair cells.
Adult ; Animals ; Cochlea* ; Cytoplasm ; Guinea Pigs* ; Hair ; Hearing Loss ; Humans ; Male ; Microscopy ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Nicotine* ; Smoke ; Smoking ; Stereocilia ; Tobacco