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At least 577 records · Page 32Linked to original sources
PubMed2003

Clinical significance of vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 in patients with nonsmall cell lung carcinoma.

BACKGROUND: Vascular endothelial growth factor C (VEGF-C) plays an important role in lymphangiogenesis and activates VEGF receptor 3 (VEGFR-3). By contrast, lymphatic spread is an important prognostic factor in patients with nonsmall cell lung carcinoma (NSCLC). The objective of the current study was to determine whether the expression of VEGF-C and VEGFR-3 correlates with clinicopathologic factors and prognosis in patients with primary NSCLC. METHODS: The authors conducted a retrospective review of 180 consecutive patients who underwent complete resection for NSCLC and who did not receive any chemotherapy or radiotherapy prior to surgery. Immunohistochemical staining for VEGF-C and VEGFR-3 was performed. The clinicopathologic implications of VEGF-C and VEGFR-3 expression were analyzed statistically. RESULTS: Of 180 patients with NSCLC, 137 patients (76.1%) were positive for VEGF-C, and 40 patients (22.2%) were positive for VEGFR-3. VEGF-C expression was observed frequently in patients with adenocarcinoma (P = 0.026). For VEGFR-3 expression, significant correlations were demonstrated with age (P = 0.02), gender (P = 0.008), and histologic differentiation in patients with squamous cell carcinoma (P = 0.03). Patients who had positive staining for VEGF-C showed significantly less favorable survival rates compared with patients who had negative staining for VEGF-C (P = 0.003). The survival rates of patients who had positive staining for VEGFR-3 also were significantly lower compared with patients who had negative staining for VEGFR-3 (P < 0.001). Patients who had positive staining for both VEGF-C and VEGFR-3 exhibited the most unfavorable prognoses. Univariate analysis revealed the following prognostic factors: gender (P = 0.03), tumor status (T1,T2 vs. T3; P < 0.01), lymph node status (negative vs. positive; P < 0.01), tumor size (< or = 35 mm vs. > 35 mm; P < 0.01), disease stage (Stage I vs. Stages II and III; P < 0.01), VEGF-C expression (negative vs. positive; P < 0.01), VEGFR-3 expression (negative vs. positive; P < 0.01) and combined VEGF-C and/or VEGFR-3 expression (both positive vs. VEGF-C or VEGFR-3 positive; P < 0.01). Multivariate analysis demonstrated that VEGFR-3 expression was the only independent negative prognostic factor (P < 0.01). CONCLUSIONS: VEGF-C and VEGFR-3 expression may be indicative of survival rates for patients with NSCLC.

Adult↗
PubMed1963

A CLASSIFICATION OF VIRUS PARTICLES BASED ON MORPHOLOGY.

Recent improvements in electron microscope techniques which allow the study of virus fine structure have permitted the grouping of many viruses on a purely morphological basis. Briefly the techniques used in electron microscopy for the study of viruses are reviewed and the symmetry properties of virus particles as revealed by negative staining are discussed somewhat more fully.Finally, virus particles are grouped on two bases, firstly the site of formation of the virus within the cell as seen by thin sectioning techniques, and secondly the symmetry property of the virus as seen by negative staining. Consideration of the groupings obtained in this way reveals that the biochemical and physical properties of a virus can be deduced from the readily established morphological characteristics.

Classification↗
PubMed1992

A combined pseudoreplica-immunochemical technique for research and diagnostic virology.

Pseudoreplica and immunochemical techniques were combined in a single protocol for identification of virus in research and clinical specimens. Stock preparations of vesicular stomatitis virus (VSV), cytomegalovirus (CMV), and herpes simplex virus (HSV) were used to develop the technique. Traditional pseudoreplicas of viral stock solutions were prepared but not negatively stained. The virus was then immunolabeled in two stages. Virus-specific polyclonal antisera were used in the first stage; colloidal gold conjugated antibodies were used as indicator antibody in the second stage. After immunolabeling, the grids were negatively stained. As a demonstration of the clinical usefulness of this approach, it was employed to antenatally identify human parvovirus B19 particles in ascites from a 22 week gestational fetus with nonimmune hydrops fetalis. The combined pseudoreplica-immunochemical approach offers several advantages over both the pseudoreplica and immunochemical methods when used in isolation. Advantages include relative purification of samples, concentration of virus, morphological preservation, and enhanced diagnostic specificity.

Cytomegalovirus↗
PubMed2000

Methanosarcina mazei strain O1M9704, methanogen with novel tubule isolated from estuarine environment.

A new methanogenic isolate, designated as strain O1M9704 (=OCM 667), was isolated from the sediment of the estuarine environment in Eriln Shi, Taiwan. This strain grew on trimethylamine and methanol, but it did not catabolize H2-CO2, acetate, or formate. Cells grew optimally at 37 degrees C with 0.5% NaCl in neutral pH. The cells were stained Gram-negative, nonmotile, irregular coccus 0.3-0.6 microm in diameter. A comparison of 16S rDNA sequences phylogenetically related strain O1M9704 to Methanosarcina mazei. Gas vacuoles were observed both under phase contrast microscope and in thin sections in the electron microscope. Negative stain of electron micrographs showed a novel character of strain O1M9704. with tubule structure extended out of the cells. The tubule structure and gas vacuoles may benefit the adaptation of methanoarchaea in estuarine environment.

Culture Media↗
PubMed1992

Cryo-EM of the native structure of the calcium release channel/ryanodine receptor from sarcoplasmic reticulum.

The native structure of the calcium release channel (ryanodine receptor) from rabbit skeletal muscle has been analyzed in two dimensions from electron micrographs of frozen hydrated specimens. Within a resolution of 3.0 nm there is excellent agreement between the structure as seen in vitreous water and in negative stained specimens. Features seen in the three-dimensional reconstruction of the negatively stained channel can be identified in the projection of the unstained receptor.

Animals↗
PubMed1973

Preservation of erythrocyte ghost ultrastructure achieved by various fixatives.

We have evaluated the quality of ultrastructural preservation of erythrocyte ghosts achieved under various electron microscopic preparative conditions. Initially, negative staining was used to monitor gross morphology of the ghosts. Of several negative stains used (phosphotungstate, silicotungstate, ammonium molybdate, and uranyl acetate), all but uranyl acetate resulted in fragmentation of membranes and the appearance of small vesicular structures. Further, preservation of gross membrane ultrastructure was greatly enhanced when samples were fixed with either 4.0-5.0% glutaraldehyde or 1% osmium tetroxide (OsO(4)) before they were stained with uranyl acetate. We then examined the ability of these fixatives to preserve membrane fine structure, as monitored by thin-sectioning procedures. In these studies, fixation with 1% osmium tetroxide (alone or in conjunction with 5% glutaraldehyde) resulted in a trilamellar image about 95 A in width. Fixation with 5% glutaraldehyde alone provided a markedly different result. The membrane now appeared as a single line about 160 A wide with regions of varying electron density throughout. This result suggests that glutaraldehyde used alone may reveal the location of membrane proteins that are obscured or removed by OsO(4) fixation. This point would seem to be supported by the results obtained when erythrocyte membranes were extracted with 5 mM EDTA after fixation in either 5% glutaraldehyde or 1% OsO(4). While only 10% of the detectable protein was solubilized from glutaraldehyde-treated erythrocyte membranes, 85% was solubilized from OsO(4)-treated ghosts. Among these latter proteins are three that migrated on Ouchterlony double-diffusion agar plates at the same position as three known proteins with molecular weights of about 200,000. Additional studies indicated that, even during a routine pre-embedding procedure, OsO(4) led to solubilization of as much as 8 times the amount of protein as glutaraldehyde alone. Although the erythrocyte membrane has a notoriously weak association with its proteins, we feel that our studies provide a cautionary note with regard to the use of OsO(4) as a fixative in other membrane systems.

Animals↗
PubMedDate not supplied

Light-microscopy evaluation of zonular fiber morphology in dogs with glaucoma: secondary to lens displacement.

Lens displacement resulting in secondary glaucoma is common in terrier breeds. This study was carried out to evaluate whether light microscopy was useful in detecting abnormal patterns in zonular fiber protein. Eyes from 63 dogs with glaucoma secondary to lens displacement were evaluated for the presence of abnormal zonular fiber morphology using the following stains: hematoxylin and eosin, periodic acid Schiff (PAS), Masson's trichrome and Verhoeff's elastin stains. Two distinct forms of abnormal zonular fiber morphology were recognized and designated as zonular fiber dysplasia (ZFD) and zonular fiber collagenization (ZFC). ZFD protein morphology was characterized by being tightly adherent to the nonpigmented ciliary body epithelium, exhibiting a distinct lamellar and cross-hatched pattern and staining strongly positive with PAS and trichrome stains, and staining negative with elastin stains. ZFD was predominant in terrier breeds (18 of 29) and Shar-Pei dogs (4 of 29). ZFC abnormality was characterized by excessive zonular fiber that was not tightly adherent to the ciliary body epithelium and staining positive with PAS, trichrome (blue for collagen) and elastin stains. Only 7 of 19 dogs with ZFC changes were terrier breeds, and there was no pattern in the breeds affected. Fifteen of the 63 dogs used in the study had normal appearing zonular fibers. The staining pattern in these dogs matched normal controls by staining positive with PAS and Verhoeff's elastin stains and had only minimal positive staining with Masson's trichrome stain. Results suggest that light microscopy is useful in detecting breed-related changes in zonular fiber morphology in cases of glaucoma secondary to lens displacement. These changes may correlate with the presence of abnormal zonular fiber proteins and might be important in the pathogenesis of primary lens displacement in terrier and Shar-Pei dogs.

Animals↗
PubMed1996

Localization of thrombomodulin in a rabbit eye.

PURPOSE: To show the distribution of an anticoagulant factor, thrombomodulin, in a rabbit eye. METHODS: Immunohistochemical staining using polyclonal anti-rabbit thrombomodulin antibody was performed with the excised eyes of pigmented adult rabbits. Streptavidin-biotin method was used to obtain intense staining. RESULTS: The endothelium of the chorioretinal vessels showed positive linear staining. The ciliary non-pigmented epithelium showed granular staining, while the pigmented epithelium stained negatively. The positive staining was also detected in the trabecular plexus endothelium. The vascular endothelium of the ciliary body stained weakly. CONCLUSIONS: It is suggested that thrombomodulin in the vessel walls and the aqueous drainage apparatus works to maintain normal blood fluidity and aqueous outflow. The role of nonvascular thrombomodulin in the ciliary non-pigmented epithelium is unclear.

Animals↗
PubMed1991

Expression of blood group antigens by normal bronchopulmonary tissues and common forms of pulmonary carcinomas.

The expression of ABH and Lewis antigens has been studied in a series of pulmonary carcinomas, in areas of squamous metaplasia, and in normal adjacent bronchopulmonary tissues by means of a panel of lectins and monoclonal antibodies. All respiratory epithelial cells can express antigens, with the exception of glandular serous cells. The expression of AB antigens is rather homogeneous, while Lewis antigens are expressed in a more irregular pattern, alternating positively stained cells with negatively stained cells in the same microscopic field. The expression of blood group antigens allows the identification of residual pneumocytes inside the tumor and the proper classification of some neoplasms. Metaplastic areas show a variation in the staining profile when compared with normal tissues and pulmonary carcinomas. The most significant findings are the deletion of A antigen and the strong expression of Le antigen. Pulmonary carcinomas are composed by a heterogeneous population and tend to express antigens in the more differentiated cases or areas. The most important findings are the deletion of AB antigens and the strong expression of Le(y) antigen.

ABO Blood-Group System↗
PubMed1991

In vitro reconstitution of recombinant lamin A and a lamin A mutant lacking the carboxy-terminal tail.

Xenopus lamin A and a lamin A mutant lacking the complete 280 amino acid long carboxy-terminal tail were expressed in bacteria and purified from inclusion bodies. Electron microscopic analysis of lamin A dimers revealed that the carboxy-terminal 280 amino acids correspond to the globular domain seen in rotary-shadowed wild-type lamin and that the rodlike domain consists of the short non-helical amino terminus and the alpha-helical region. During reconstitution lamin A dimers first formed polar head to tail aggregates which then associated laterally resulting in paracrystals with periodic repeats of 25 nm. In the mutant, the longitudinal and lateral association of dimers had not been influenced, however, periodic repeats were absent in the filament bundles formed. Thus our data clearly demonstrate that carboxy-terminal tails are localized in light-stained regions of negatively stained paracrystals and that they are responsible for the alternating light dark staining of paracrystals. Fibrils, 2 to 3 nm thick, were a common structural element of paracrystals and filament bundles.

Animals↗
PubMedDate not supplied

Immunoperoxidase staining of fine needle aspiration specimens previously stained by the Papanicolaou technique.

The use of immunoperoxidase techniques was investigated in 21 fine needle aspiration (FNA) cytology smears that had been previously stained by the Papanicolaou technique. The retrospectively selected slides were destained before applying the immunostain, utilizing antisera to calcitonin, prostatic acid phosphatase (PrAP), prostate-specific antigen (PSA), alpha-lactalbumin (AL), S-100 protein (S-100), carcinoembryonic antigen (CEA), common leukocyte antigen (LA), epithelial membrane antigen (EMA) and alpha-fetoprotein (AFP). Positive results were obtained with six of nine small-cell carcinomas of the lung stained with EMA, all three colonic carcinomas stained with CEA, one of two prostatic carcinomas stained with PSA and PrAP, one of two lymphomas stained with LA and the one medullary thyroid carcinoma stained with calcitonin. Negative staining results were observed in the one melanoma stained with S-100, the two breast carcinomas stained with AL and the one hepatocellular carcinoma stained with AFP. These results indicate that immunostaining can be a helpful diagnostic tool in diagnosing some fine needle aspirates using smears previously stained with the Papanicolaou stain.

Biopsy, Needle↗
PubMed1994

[Expression of mutant p53 in chronic HBV infection and hepatocellular carcinoma].

In order to investigate the expression of mutant p53 protein (Mp53) and HBxAg in chronic active hepatitis (CH) and hepatocellular carcinoma (HCC), 30 specimens of HCC with surrounding liver tissues (SL), 15 biopsy specimens from CH were examined with immunohistochemical method (ABC system). The results showed, that 13 (43.3%) specimens of HCC and 15 (50%) of SL were positive for MP53 and HBxAg staining; 3 (16.7%) of HCC and 8 (26.7%) of SL were only MP53 positive, being HBxAg staining negative. On the contrary, 4 (13.3%) of HCC and 1 (3%) of SL were negative for MP53 staining and positive for HBxAg staining (P < 0.05, chi 2 test). In 15 specimens of CH, 3 cases were positive for MP53, 2 for HBxAg. The results indicate that there is a correlation between mutant p53 protein and HBxAg, suggesting that the p53 gene mutation may be closely related with HBV infection, and the mutation of p53 gene would be one of hepatocarcinogenesis mechanisms of HBV.

Adult↗
PubMed1999

Steam heat with an EDTA buffer and protease digestion optimizes immunohistochemical expression of basal cell-specific antikeratin 34betaE12 to discriminate cancer in prostatic epithelium.

In select cases of prostatic carcinoma, antikeratin 34betaE12 immunohistochemical analysis is diagnostically useful for specific labeling of basal cells. This antibody, however, is prone to variability in staining, and the optimal conditions were not, to our knowledge, previously defined. We combined steam heat with EDTA buffer (steam-EDTA) and protease digestion (steam-EDTA + protease) to optimize epitope retrieval of antikeratin 34betaE12 in 42 cases of prostatic cancer. Results were judged by the percentage of cells staining and by staining intensity. In benign epithelium, steam-EDTA + protease significantly increased the percentage of immunoreactive cells (from 74 to 93%) and the intensity of staining (from 2.1 to 3.0 on a scale of 0-3+) by comparison with protease alone (all P<.001). In high-grade prostatic intraepithelial neoplasia, the percentage of cells staining increased from 55 to 73% and intensity increased from 1.7 to 2.8 (both P<.001). Steam-EDTA + protease also minimized variability in results between cases, with essentially no background stromal staining. Cancer was negative in all of our cases by both methods. We conclude that steam-EDTA + protease significantly enhances basal cell immunoreactivity compared with protease treatment alone in noncancerous prostatic epithelium. This helps to prevent misinterpretation of histologic mimics of cancer, such as atrophic acini and high-grade prostatic intraepithelial neoplasia, that result from false-negative staining.

Antibodies, Monoclonal↗
PubMed1998

Characterization and applications of a monoclonal antibody against infectious salmon anaemia virus.

The preparation of the first monoclonal antibody (MAb) against the orthomyxovirus-like infectious salmon anaemia (ISA) virus is described. Characterization of the MAb included isotyping, enzyme-linked immunosorbent assay (ELISA), immunofluorescent staining of virus infected cell cultures (SHK-1 cells), immunoelectron microscopy (IEM) of negatively stained virus preparations, virus neutralization assay and haemagglutination inhibition assay. The MAb reacted with ISA virus preparations both with immunofluorescent staining and in ELISA. No reactions were observed in cell cultures infected with other viruses infecting salmonids including infectious pancreatic necrosis (IPN) virus, viral haemorrhagic septicaemia (VHS) virus and infectious haematopoietic necrosis (IHN) virus. The MAb was also shown to neutralize ISA virus infection in cell cultures and to inhibit the haemagglutination reaction. IEM demonstrated binding to the surface of negatively stained ISA virions. Thus, it is concluded that the MAb binds to the haemagglutinin on the virion surface. Furthermore, using immunofluorescent staining of virus infected cell cultures, reactivity against all the 13 ISA virus strains currently available was demonstrated. Using the MAb, a simple, rapid direct immunofluorescent assay for ISA virus detection and titration in 96-well tissue culture plates was developed. Infectivity titrations by this method correlated well with titration by cytopathic effects. The reliability of the assay was demonstrated by close agreement in virus infectivity titres among different assays for the same virus that were performed on the same day and on different days. A method for detection of viral antigen in cryosections from ISA diseased fish is also reported that may prove useful for the diagnosis and control of ISA.

Animals↗
PubMed2002

Pure F-actin networks are distorted and branched by steps in the critical-point drying method.

Elucidation of the ultrastructural organization of actin networks is crucial for understanding the molecular mechanisms underlying actin-based motility. Results obtained from cytoskeletons and actin comets prepared by the critical-point procedure, followed by rotary shadowing, support recent models incorporating actin filament branching as a main feature of lamellipodia and pathogen propulsion. Since actin branches were not evident in earlier images obtained by negative staining, we explored how these differences arise. Accordingly, we have followed the structural fate of dense networks of pure actin filaments subjected to steps of the critical-point drying protocol. The filament networks have been visualized in parallel by both cryo-electron microscopy and negative staining. Our results demonstrate the selective creation of branches and other artificial structures in pure F-actin networks by the critical-point procedure and challenge the reliability of this method for preserving the detailed organization of actin assemblies that drive motility.

Actins↗
PubMed2001

Novel filaments 5 nm in diameter constitute the cytosolic ring of the plastid division apparatus.

The plastid division apparatus (called the plastid-dividing ring) has been detected in several plant and algal species at the constricted region of plastids by transmission electron microscopy. The apparatus is composed of two or three rings: an outer ring in the cytosol, an inner ring in the stroma, and a middle ring in the intermembrane space. The components of these rings are not clear. FtsZ, which forms the bacterial cytokinetic ring, has been proposed as a component of both the inner and outer rings. Here, we present the ultrastructure of the outer ring at high resolution. To visualize the outer ring by negative staining, we isolated dividing chloroplasts from a synchronized culture of a red alga, Cyanidioschyzon merolae, and lysed them with nonionic detergent Nonidet P-40. Nonidet P-40 extracted primarily stroma, thylakoids, and the inner and middle rings, leaving the envelope and outer ring largely intact. Negative staining revealed that the outer ring consists of a bundle of 5-nm filaments in which globular proteins are spaced 4.8 nm apart. Immunoblotting using an FtsZ-specific antibody failed to show immunoreactivity in the fraction containing the filament. Moreover, the filament structure and properties are unlike those of known cytoskeletal filaments. The bundle of filaments forms a very rigid structure and does not disassemble in 2 M urea. We also identified a dividing phase-specific 56-kD protein of chloroplasts as a candidate component of the ring. Our results suggest that the main architecture of the outer ring did not descend from cyanobacteria during the course of endosymbiosis but was added by the host cell early in plant evolution.

Actin Cytoskeleton↗
PubMed1997

Electron microscopy of biological specimens by the plasma-polymerization rapid-freeze replica method.

The plasma-polymerization replica method is a unique replica technique for transmission electron microscopy. In the present study, we used this method in combination with a rapid-freeze technique to observe T4 bacteriophages and hepatitis B virus core particles. The heads of T4 bacteriophages appeared hexagonal and measured approximately 110 nm in length. Striations in their tails were also visible, indicating that the resolution of the present method is better than 4 nm. The images corresponded well with those obtained by ice-embedding and negative staining methods, with respect to both morphology and size of the phage particle. Hepatitis B virus core particles observed by the present method appeared round, approximately 30 nm in diameter, with hollow centres. Again, the morphology and size of the particles corresponded well with those obtained by ice-embedding, negative staining, and ultrathin sectioning. From these results, we conclude that the plasma-polymerization rapid-freeze replica method provides a useful technique for observation of biological specimens in a natural state and at high resolution.

Aluminum Silicates↗
PubMed1980

Scanning transmission electron microscopy of biological macromolecules.

The practical usefulness of a STEM (Scanning Transmission Electron Microscope) for the study of the structure of biological macromolecules has been investigated using a STEM attachment connected to a TEM (Transmission Electron Microscope), which in one case was equipped with a tungsten hairpin cathode, and in the other case with a field emission gun. The point to point resolution has been determined. Results obtained in STEM dark field from light negatively stained specimens are compared with results obtained in TEM bright field from normal negatively stained specimens. In addition unstained molecules have been visualized. Some remarks are made about preparation methods suitable for STEM.

Animals↗