bluuebunny/crossref_metadata_2025 huggingface dataset:
High-level IGF1R expression is required for leukemia-initiating cell activity in T-ALL and is supported by Notch signaling
Authors: Medyouf Hind , Gusscott Samuel , Wang Hongfang , Tseng Jen-Chieh , Wai Carol , Nemirovsky Oksana , Trumpp Andreas , Pflumio Francoise , Carboni Joan , Gottardis Marco , Pollak Michael , Kung Andrew L. , Aster Jon C. , Holzenberger Martin , Weng Andrew P.
Published: August 2011

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer of immature T cells that often shows aberrant activation of Notch1 and PI3K–Akt pathways. Although mutations that activate PI3K–Akt signaling have previously been identified, the relative contribution of growth factor-dependent activation is unclear. We show here that pharmacologic inhibition or genetic deletion of insulin-like growth factor 1 receptor (IGF1R) blocks the growth and viability of T-ALL cells, whereas moderate diminution of IGF1R signaling compromises leukemia-initiating cell (LIC) activity as defined by transplantability in syngeneic/congenic secondary recipients. Furthermore, IGF1R is a Notch1 target, and Notch1 signaling is required to maintain IGF1R expression at high levels in T-ALL cells. These findings suggest effects of Notch on LIC activity may be mediated in part by enhancing the responsiveness of T-ALL cells to ambient growth factors, and provide strong rationale for use of IGF1R inhibitors to improve initial response to therapy and to achieve long-term cure of patients with T-ALL.
NIK signaling in dendritic cells but not in T cells is required for the development of effector T cells and cell-mediated immune responses
Authors: Hofmann Janin , Mair Florian , Greter Melanie , Schmidt-Supprian Marc , Becher Burkhard
Published: August 2011

The canonical NF-κB pathway is a driving force for virtually all aspects of inflammation. Conversely, the role of the noncanonical NF-κB pathway and its central mediator NF-κB–inducing kinase (NIK) remains poorly defined. NIK has been proposed to be involved in the formation of TH17 cells, and its absence in TH cells renders them incapable of inducing autoimmune responses, suggesting a T cell–intrinsic role for NIK. Upon systematic analysis of NIK function in cell-mediated immunity, we found that NIK signaling is dispensable within CD4+ T cells but played a pivotal role in dendritic cells (DCs). We discovered that NIK signaling is required in DCs to deliver co-stimulatory signals to CD4+ T cells and that DC-restricted expression of NIK is sufficient to restore TH1 and TH17 responses as well as cell-mediated immunity in NIK−/− mice. When CD4+ T cells developed in the absence of NIK-sufficient DCs, they were rendered anergic. Reintroduction of NIK into DCs allowed developing NIK−/− CD4+ T cells to become functional effector populations and restored the development of autoimmune disease. Therefore, our data suggest that a population of thymic DCs requires NIK to shape the formation of most αβ CD4+ T effector lineages during early development.
CD1b tetramers bind αβ T cell receptors to identify a mycobacterial glycolipid-reactive T cell repertoire in humans
Authors: Kasmar Anne G. , van Rhijn Ildiko , Cheng Tan-Yun , Turner Marie , Seshadri Chetan , Schiefner Andre , Kalathur Ravi C. , Annand John W. , de Jong Annemieke , Shires John , Leon Luis , Brenner Michael , Wilson Ian A. , Altman John D. , Moody D. Branch
Published: August 2011

Microbial lipids activate T cells by binding directly to CD1 and T cell receptors (TCRs) or by indirect effects on antigen-presenting cells involving induction of lipid autoantigens, CD1 transcription, or cytokine release. To distinguish among direct and indirect mechanisms, we developed fluorescent human CD1b tetramers and measured T cell staining. CD1b tetramer staining of T cells requires glucose monomycolate (GMM) antigens, is specific for TCR structure, and is blocked by a recombinant clonotypic TCR comprised of TRAV17 and TRBV4-1, proving that CD1b–glycolipid complexes bind the TCR. GMM-loaded tetramers brightly stain a small subpopulation of blood-derived cells from humans infected with Mycobacterium tuberculosis, providing direct detection of a CD1b-reactive T cell repertoire. Polyclonal T cells from patients sorted with tetramers are activated by GMM antigens presented by CD1b. Whereas prior studies emphasized CD8+ and CD4−CD8− CD1b-restricted clones, CD1b tetramer-based studies show that nearly all cells express the CD4 co-receptor. These findings prove a cognate mechanism whereby CD1b–glycolipid complexes bind to TCRs. CD1b tetramers detect a natural CD1b-restricted T cell repertoire ex vivo with unexpected features, opening a new investigative path to study the human CD1 system.
𝐴_{∞} estimates via extrapolation of Carleson measures and applications to divergence form elliptic operators
Authors: Hofmann Steve , Martell José María
Published: August 2011

We revisit the “extrapolation method” for Carleson measures, introduced by Lewis and Murray (1995), to prove

A
∞

A_\infty

estimates for certain caloric measures, and we present a purely real variable version of the method suitable for establishing

A
∞

A_\infty

estimates. To illustrate the use of this technique, we then reprove a well-known result of Fefferman, Kenig, and Pipher (1991).
A Comparative Transcriptome Analysis of Rhizobium etli Bacteroids: Specific Gene Expression During Symbiotic Nongrowth
Authors: Vercruysse Maarten , Fauvart Maarten , Beullens Serge , Braeken Kristien , Cloots Lore , Engelen Kristof , Marchal Kathleen , Michiels Jan
Published: August 2011

Rhizobium etli occurs either in a nitrogen-fixing symbiosis with its host plant, Phaseolus vulgaris, or free-living in the soil. During both conditions, the bacterium has been suggested to reside primarily in a nongrowing state. Using genome-wide transcriptome profiles, we here examine the molecular basis of the physiological adaptations of rhizobia to nongrowth inside and outside of the host. Compared with exponentially growing cells, we found an extensive overlap of downregulated growth-associated genes during both symbiosis and stationary phase, confirming the essentially nongrowing state of nitrogen-fixing bacteroids in determinate nodules that are not terminally differentiated. In contrast, the overlap of upregulated genes was limited. Generally, actively growing cells have hitherto been used as reference to analyze symbiosis-specific expression. However, this prevents the distinction between differential expression arising specifically from adaptation to a symbiotic lifestyle and features associated with nongrowth in general. Using stationary phase as the reference condition, we report a distinct transcriptome profile for bacteroids, containing 203 induced and 354 repressed genes. Certain previously described symbiosis-specific characteristics, such as the downregulation of amino acid metabolism genes, were no longer observed, indicating that these features are more likely due to the nongrowing state of bacteroids rather than representing bacteroid-specific physiological adaptations.
First Report of Potato mop-top virus on Potatoes in Washington State
Authors: Crosslin J. M.
Published: August 2011

In April of 2011, approximately 10% of the tubers of potato (Solanum tuberosum L.) cv. Alturas, grown in central Washington State and collected from a commercial potato storage facility, were observed to have internal brown spots and arcs typical of infection by either Tobacco rattle virus (TRV) or Potato mop-top virus (PMTV). Ten tubers showing symptoms ranging from a few brown spots to large (2 cm) concentric arcs were tested by reverse transcription (RT)-PCR with primers specific for TRV (3) or PMTV (PMTV2 forward, AGAGCAGCCGTCGAGAATAG; PMTV3 reverse, TCGTCCACCTCTGCGAGTTG). Two symptomless tubers from the same lot were also tested. All symptomatic tubers tested negative for TRV, but eight of the symptomatic tubers were positive for PMTV, as evidenced by production of the expected 416-bp amplified DNA product. The symptomless tubers were negative for both viruses. The eight symptomatic tubers that were positive for PMTV by RT-PCR were also positive for PMTV by ELISA using a commercially available kit (Adgen, Ayr, Scotland). The symptomless tubers were negative for PMTV by ELISA. The 416-bp amplicons obtained with the PMTV primers from two tubers were cloned and three clones of each were sequenced. The consensus sequences for the two samples differed by only one nucleotide and sequences were deposited in GenBank as Accession Nos. JN132116 and JN132117. BLAST analysis showed the sequences were 99 to 100% identical to a portion of the coat protein gene of numerous PMTV isolates. These results confirm that PMTV is present in central Washington State. The virus has been known to affect potatoes in Maine for several years (2) and was recently confirmed in North Dakota (1). PMTV was reportedly found in potatoes grown in numerous locations in the United States, but the specific locations were not reported (4). PMTV is transmitted by the soilborne powdery scab pathogen, Spongospora subterranea, which is widespread in the region of the state where the virus-infected tubers were grown. The confirmation of PMTV in Washington State alerts growers, fieldmen, and diagnostic laboratories to the presence of this potentially serious virus in a major potato-production area of the United States.

References: (1) N. David et al. Plant Dis. 94:1506, 2010. (2) D. H. Lambert et al. Plant Dis. 87:872, 2003. (3) D. J. Robinson. J. Virol. Methods 40:57, 1992. (4) H. Xu et al. Plant Dis. 88:363, 2004.
Functional Characterization of Evolutionarily Divergent 4-Coumarate:Coenzyme A Ligases in Rice
Authors: Gui Jinshan , Shen Junhui , Li Laigeng
Published: August 2011

4-Coumarate:coenzyme A ligase (4CL; EC 6.2.1.12) is a key enzyme in the phenylpropanoid metabolic pathways for monolignol and flavonoid biosynthesis. 4CL has been much studied in dicotyledons, but its function is not completely understood in monocotyledons, which display a different monolignol composition and phenylpropanoid profile. In this study, five members of the 4CL gene family in the rice (Oryza sativa) genome were cloned and analyzed. Biochemical characterization of the 4CL recombinant proteins revealed that the rice 4CL isoforms displayed different substrate specificities and catalytic turnover rates. Among them, Os4CL3 exhibited the highest turnover rate. No apparent tissue-specific expression of the five 4CLs was observed, but significant differences in their expression levels were detected. The rank in order of transcript abundance was Os4CL3 > Os4CL5 > Os4CL1 > Os4CL4 > Os4CL2. Suppression of Os4CL3 expression resulted in significant lignin reduction, shorter plant growth, and other morphological changes. The 4CL-suppressed transgenics also displayed decreased panicle fertility, which may be attributed to abnormal anther development as a result of disrupted lignin synthesis. This study demonstrates that the rice 4CLs exhibit different in vitro catalytic properties from those in dicots and that 4CL-mediated metabolism in vivo may play important roles in regulating a broad range of biological events over the course of rice growth and development.
Spontaneous rejection of intradermally transplanted non‐engineered tumor cells by neutrophils and macrophages from syngeneic strains of mice
Authors: Ibata Minenori , Takahashi Takeshi , Shimizu Tetsunosuke , Inoue Yoshihiro , Maeda Shogo , Tashiro‐Yamaji Junko , Okada Masashi , Ueda Koichi , Kubota Takahiro , Yoshida Ryotaro
Published: August 2011

It is not surprising that tumors arising spontaneously are rarely rejected by T cells, because in general they lack molecules to elicit a primary T‐cell response. In fact, cytokine‐engineered tumors can induce granulocyte infiltration leading to tumor rejection. In the present study, we i.d. injected seven kinds of non‐engineered tumor cells into syngeneic strains of mice. Three of them (i.e. B16, KLN205, and 3LL cells) continued to grow, whereas four of them (i.e. Meth A, I‐10, CL‐S1, and FM3A cells) were spontaneously rejected after transient growth or without growth. In contrast to the i.d. injection of B16 cells into C57BL/6 mice, which induces infiltration of TAMs into the tumors, the i.d. injection of Meth A cells into BALB/c mice induced the invasion of cytotoxic inflammatory cells, but not of TAMs, into or around the tumors leading to an IFN‐γ‐dependent rejection. On day 5, the cytotoxic activity against the tumor cells reached a peak; and the effector cells were found to be neutrophils and macrophages. The i.d. Meth A or I‐10 cell‐immunized, but not non‐immunized, mice rejected i.p.‐ or i.m.‐transplanted Meth A or I‐10 cells without growth, respectively. The main effector cells were CTLs; and there was no cross‐sensitization between these two kinds of tumor cells, suggesting specific rejection of tumor cells by CTLs from i.d. immunized mice. These results indicate that infiltration of cytotoxic myeloid cells (i.e. neutrophils and macrophages, but not TAMs) into or around tumors is essential for their IFN‐γ‐dependent spontaneous rejection.
Systems genetics approach reveals candidate genes for parasite resistance from quantitative trait loci studies in agricultural species
Authors: Sayre B. L. , Harris G. C.
Published: August 2011

A systems genetics approach combining pathway analysis of quantitative trait loci (QTL) and gene expression information has provided strong evidence for common pathways associated with genetic resistance to internal parasites. Gene data, collected from published QTL regions in sheep, cattle, mice, rats and humans, and microarray data from sheep, were converted to human Entrez Gene IDs and compared to the KEGG pathway database. Selection of pathways from QTL data was based on a selection index that ensured that the selected pathways were in all species and the majority of the projects overall and within species. Pathways with either up‐ and down‐regulated genes, primarily up‐regulated genes or primarily down‐regulated genes, were selected from gene expression data. After comparing the data sets independently, the pathways from each data set were compared and the common set of pathways and genes was identified. Comparisons within data sets identified 21 pathways from QTL data and 66 pathways from gene expression data. Both selected sets were enriched with pathways involved in immune functions, disease and cell responses to signals. The analysis identified 14 pathways that were common between QTL and gene expression data, and four directly associated with IFNγ or MHCII, with 31 common genes, including three MHCII genes. In conclusion, a systems genetics approach combining data from multiple QTL and gene expression projects led to the discovery of common pathways associated with genetic resistance to internal parasites. This systems genetics approach may prove significant for the discovery of candidate genes for many other multifactorial, economically important traits.
Quantitative trait loci segregating in crosses between New Hampshire and White Leghorn chicken lines: I. egg production traits
Authors: Goraga Z. S. , Nassar M. K. , Brockmann G. A.
Published: August 2011

A genome scan was performed to detect chromosomal regions that affect egg production traits in reciprocal crosses between two genetically and phenotypically extreme chicken lines: the partially inbred line New Hampshire (NHI) and the inbred line White Leghorn (WL77). The NHI line had been selected for high growth and WL77 for low egg weight before inbreeding. The result showed a highly significant region on chromosome 4 with multiple QTL for egg production traits between 19.2 and 82.1 Mb. This QTL region explained 4.3 and 16.1% of the phenotypic variance for number of eggs and egg weight in the F2 population, respectively. The egg weight QTL effects are dependent on the direction of the cross. In addition, genome‐wide suggestive QTL for egg weight were found on chromosomes 1, 5, and 9, and for number of eggs on chromosomes 5 and 7. A genome‐wide significant QTL affecting age at first egg was mapped on chromosome 1. The difference between the parental lines and the highly significant QTL effects on chromosome 4 will further support fine mapping and candidate gene identification for egg production traits in chicken.
Fine mapping of porcine SSC14 QTL and SCD gene effects on fatty acid composition and melting point of fat in a Duroc purebred population
Authors: Uemoto Y. , Nakano H. , Kikuchi T. , Sato S. , Ishida M. , Shibata T. , Kadowaki H. , Kobayashi E. , Suzuki K.
Published: August 2011

The stearoyl‐CoA desaturase (delta‐9‐desaturase; SCD) gene is a candidate gene for fatty acid composition. It is located on pig SSC14 in a region where quantitative trait loci (QTL) for fatty acid composition were previously detected in a Duroc purebred population. The objective of the present study was to fine map the QTL, to identify polymorphisms of the pig SCD gene and to examine the effects of SCD polymorphisms on fatty acid composition and melting point of fat in the population. The pigs were examined for fatty acid composition and melting point of inner and outer subcutaneous fat and inter‐ and intramuscular fat; the number of pigs examined was 479–521. Two SNPs (g.−353C>T and g.−233T>C) were identified in the promoter region of the SCD gene and were completely linked in the pigs from the base generation. In all pigs, 19 microsatellite markers and SCD haplotypes were then genotyped. Different statistical models were applied to evaluate the effects of QTL and the possible causality of the SCD gene variants with respect to the QTL. The results show that all significant QTL for C14:0, C18:0, C18:1 and melting point of fat were detected in the same region, located near the SCD gene. The results also show a significant association between SCD haplotypes and fatty acid composition and fat melting point in this population. These results indicate that the haplotype of the SCD gene has a strong effect on fatty acid composition and melting point of fat.
Pulmonary function in thalassaemia major and its correlation with body iron stores
Authors: Sohn Eugene Y. , Noetzli Leila J. , Gera Aakanksha , Kato Roberta , Coates Thomas D. , Harmatz Paul , Keens Thomas G. , Wood John C.
Published: August 2011

This study compared pulmonary function tests (PFTs) with cardiac, pancreatic and liver iron in 76 thalassemia major (TM) patients. Restrictive lung disease was observed in 16%, hyperinflation in 32% and abnormal diffusing capacity in 3%. While no patients met Global Initiative for Chronic Lung Disease criteria for airways obstruction, there were indicators of small airways disease and air trapping. PFTs did not correlate with somatic iron burden, blood counts or haemolysis. Restrictive lung disease was associated with inflammation. We conclude that TM patients have pulmonary abnormalities consistent with small airways obstruction. Restrictive disease and impaired diffusion are less common.
Bacterial growth trend of a dried Japanese common squid (Todarodes pacificus Steenstrup) characterised by dehydration
Authors: Konishi Yasuyuki , Kobayashi Masayoshi , Kawai Yuji
Published: August 2011

The bacterial contamination of dried Japanese common squid was effectively controlled by regulating the distribution of two water species retained in a Japanese common squid mantle. The two water species were distinguished as water species‐A1, a mobile‐water species and water species‐A2, a relatively restricted‐water species. Water species‐A1 and ‐A2 were effectively characterised by a physicochemical parameter, the correlation time (τC, s), which was evaluated using a proton NMR analysis. The bacterial count was evaluated as a function of τC and the relative humidity (RH), and the results precisely demonstrated the existence of a critical τC (CτC = 10−8 s) at which the water species were divided into species‐A1 (region I < CτC) and ‐A2 (region II > CτC). Bacterial growth was completely interrupted by species‐A2 or by an RH lower than 30% (designated as RH30) at <103 CFU g−1. In region I, at higher than RH30, the dominant genera of the bacteria observed were identified as Micrococcus and Staphylococcus.
Effects of β‐cyclodextrin addition and farming type on vitamin C, antioxidant activity, carotenoids profile, and sensory analysis in pasteurised orange juices
Authors: Navarro Patricia , Melendez‐Martinez Antonio Jesus , Heredia Francisco , Gabaldon Jose Antonio , Carbonell‐Barrachina Ángel Antonio , Soler Antonio , Perez‐Lopez Antonio José
Published: August 2011

The effects of organic farming, pasteurisation and addition of β‐cyclodextrin on the content of vitamin C, colour, carotenoids and antioxidant capacity of orange juices were studied. After pasteurisation at 98 °C (20 s) and subsequently storage along 145 days at room temperature (20–25 °C), the loss of vitamin C content was around 30%. The effects of the thermal process on carotenoid were clearly observed in lutein (loss of 16% for organic and traditional 8%) and especially β‐cryptoxanthin (loss of 30%). The colour changes were noticeable after the pasteurisation of orange juice and subsequent storage, with significant decreases being observed in lightness and the coordinate a*, while increases were found for coordinates b*, Hue* and chroma. The antioxidant capacity was 0.075 ± 0.01 and 0.053 ± 0.01 mMT mL−1 for organic and conventional, respectively, with losses around 40% being found at the end of the storage period. The addition of β‐cyclodextrin caused no significant effects on the parameters under analysis. These data showed that strong thermal treatments, such as pasteurisation, adversely affect the nutritional and sensory quality of orange juices.
The questionable promise of social media for education: connective learning and the commercial imperative
Authors: Friesen N. , Lowe S.
Published: August 2011

Facebook and other social media have been hailed as delivering the promise of new, socially engaged educational experiences for students in undergraduate, self‐directed, and other educational sectors. A theoretical and historical analysis of these media in the light of earlier media transformations, however, helps to situate and qualify this promise. Specifically, the analysis of dominant social media presented here questions whether social media platforms satisfy a crucial component of learning – fostering the capacity for debate and disagreement. By using the analytical frame of media theorist Raymond Williams, with its emphasis on the influence of advertising in the content and form of television, we weigh the conditions of dominant social networking sites as constraints for debate and therefore learning. Accordingly, we propose an update to Williams' erudite work that is in keeping with our findings. Williams' critique focuses on the structural characteristics of sequence, rhythm, and flow of television as a cultural form. Our critique proposes the terms information design, architecture, and above all algorithm, as structural characteristics that similarly apply to the related but contemporary cultural form of social networking services. Illustrating the ongoing salience of media theory and history for research in e‐learning, the article updates Williams' work while leveraging it in a critical discussion of the suitability of commercial social media for education.
Comparing residential programmes for adults with autism spectrum disorders and intellectual disability: outcomes of challenging behaviour and quality of life
Authors: Gerber F. , Bessero S. , Robbiani B. , Courvoisier D. S. , Baud M. A. , Traoré M.‐C. , Blanco P. , Giroud M. , Galli Carminati G.
Published: August 2011

Background  Owing to methodological issues, little research has been conducted to examine quality of life (QoL) as a treatment outcome in autism spectrum disorders (ASD) and intellectual disabilities (ID). This study was conducted to combine QoL measures and objective observations of challenging behaviours (CB) in order to evaluate changes over time in adults with ASD and ID who were treated in two different residential programmes; we hypothesised that a decrease in CB would be related to an improved QoL.

Method  In a longitudinal study (45 months), we followed 31 adults with ASD and ID who had been integrated into two residential programmes [Autism Programme with a Structured Method (PAMS) vs. traditional programme for ID (No‐PAMS)] for 2–19 years. QoL [Quality of Life Inventory in a Residential Environment (IQVMR)] and severity of autistic features (Childhood Autism Rating Scales) were evaluated annually. CB, as measured by the Aberrant Behaviour Checklist (ABC), including stereotypic behaviour and inappropriate speech, were repeatedly assessed every 3 months.

Results  Observed separately, the groups' results were different. In the PAMS programme, stereotypic behaviour and inappropriate speech (ABC scores) significantly decreased, and the IQVMR total score increased; in contrast, in the comparison group, ABC scores did not change and the IQVMR total score decreased. In all, three mixed‐effect ANCOVAs partially confirmed that the PAMS programme had an effect on CB and that QoL improvement did not directly depend on the type of programme but on reducing CB as measured by the ABC.

Conclusion  The PAMS programme has a positive and indirect influence on QoL by reducing CB.
Electron microscopy of lipids: Effects of pH and fixatives on the appearance of a macromolecular assembly of lipid micelles in negatively stained preparations
Authors: Glauert Audrey M. , Lucy J. A.
Published: August 2011

Negatively stained preparations of macromolecular assemblies composed of lecithin, cholesterol and saponin have been examined by electron microscopy. Studies were made of the effects of different negative stains, pH and fixatives on the self‐assembly process that gives rise to helical and related structures, on the characteristic appearance of the structures that are formed, and on the stability of the different assemblies. A variety of different macromolecular assemblies, each apparently made of globular lipid subunits arranged in different ways, were observed under different experimental conditions. The structural appearance of the assemblies changes rapidly when the chemical constitution of the aqueous environment is altered. It is concluded that the negative‐staining technique normally provides an image of the hydrated specimen so that drying artifacts are not a major hazard, but the possibility of interactions between the specimen and the aqueous negative‐staining solution must not be ignored. The observations reported in this paper are relevant to an understanding of the factors that may control the formation, in vivo, of those biological membranes that contain discrete subunits composed of lipids or lipoproteins.
Light‐microscopic radioautography utilizing araldite sections
Authors: Hodson S. A.
Published: August 2011

A report is presented of light‐microscopic radioautography over araldite sections using either a stripping film (AR10) or a nuclear dipping emulsion (G5) as detector. Except for anomalies at the beginning of the exposure, both emulsions have similar sensitivities, resolutions and latent image‐fading characteristics. The stripping film technique has some disadvantages including the necessity of staining the tissue before application of the film. A short list of familiar tissue stains and their chemographic properties is presented. The self absorption of araldite sections to the electron emitted from a tritium atom is measured and its significance for reproducible results commented upon.
A rapid methylene blue‐basic fuchsin stain for semi‐thin sections of peripheral nerve and other tissues
Authors: Aparicio S. R. , Marsden P.
Published: August 2011

Differential histological staining of various tissues is achieved in epon, araldite or glycol methacrylate sections 0·25–0·5 μ thick, from human, guinea‐pig and rat origin. The staining procedure is as follows: 1% methylene blue in 1% borax 15–30 sec at 70°C; wash in hot water; 2% basic fuchsin in distilled water 1–2 min at room temperature; wash and mount in DPX. Results: with all tissues: nuclei pale violet, cytoplasm blue. Special histological components: collagen red, myelin deep blue, elastin deep violet, axoplasm pale blue. Although of general utility the method is especially useful for peripheral nerve and blood vessels.
Birefringence phenomena in cylindrical fibres
Authors: Thetford A. , Simmens S. C.
Published: August 2011

The interference pattern seen in a birefringent cylindrically shaped fibre, e.g. a nylon fibre, when viewed through a polarizing microscope has been used by different workers to provide information about radial inhomogeneity of the internal structure of the fibres. This interference pattern is now shown to be markedly influenced by the mounting medium containing the fibre and an explanation for this behaviour, based on geometrical optics, is given.
Visualization of substructure in ferritin molecules: An artifact
Authors: Haydon Glen B.
Published: August 2011

It has been suggested in the literature that the core of the ferritin molecule contains a tetrad or other substructure resolvable in electron micrographs. The work described in this paper indicates:

1. At a potential resolution of 5 Å, near‐focus electron micrographs of ferritin molecules show no substructure in the core.

2. By defocusing the microscope a computed amount, electron micrographs of the same ferritin molecule can be produced which show apparent core substructure similar to that shown in several patterns reported in the literature.

3. Apparent ferritin molecules with or without substructure, depending upon the phase granularity in the negative, can be added in printing by over‐exposing an area of the background equal in size to a ferritin molecule.

4. Underfocus contrast enhancement, frequently used by electron microscopists at lower magnifications without loss of resolution, does result in a loss of resolution at maximum useful magnifications.

5. The established physical principles of electron‐optical image formation which should be applied to all high‐resolution electron microscopy to distinguish substructure from artifact, are reviewed.

This work is compatible with recent X‐ray diffraction studies of ferritin molecules which indicate that iron‐containing micelles in the core of ferritin are smaller than the practical resolution of the best electron microscopes and therefore neither they nor their substructure could be imaged.
Studies of steel fracture by transmission and scanning electron microscopy
Authors: Treadaway K. W. J.
Published: August 2011

Transmission electron micrographs of replicas of the fractured surfaces of steel are compared with scanning electron micrographs of areas of the same surfaces. The advantages of each method are discussed.
A combined PAS‐myofibril stain for demonstration of early lesions of striated muscle
Authors: Puchtler Holde , Waldrop Faye Sweat , Terry Mary S. , Conner H. M.
Published: August 2011

To facilitate studies of early myocardial lesions a method was developed for simultaneous demonstration of saccharides and muscle proteins. Deparaffinized sections were treated consecutively with the PAS reaction, tannic acid, phosphomolybdic acid and Levanol fast cyanine 5RN. A and Z bands in normal muscle were stained blue. I bands were coloured yellow. Under various pathological conditions A and Z bands lost their affinity for Levanol fast cyanine 5RN, with and without appearance of PAS‐positive material in the Z bands.

Comparison of staining patterns with chemical, electron microscopic and X‐ray diffraction data indicated that Levanol fast cyanine 5RN is bound by myosin and tropomyosin B. This affinity is lost when the protein structure is altered. The origin of the PAS‐positive material appearing in the Z bands could not yet be determined.
Scanning electron microscopy of intestinal microvilli
Authors: Millington P. F. , Critchley D. R. , Tovell P. W. A. , Pearson R.
Published: August 2011

The usual simple methods for the preparation of soft tissues for scanning electron microscopy failed to demonstrate the presence of microvilli on intestinal epithelial cells from rats. Treatment with a mucolytic agent or surface‐section methods also failed. However, the isolation of the brush borders as the first step in the preparatory procedure did allow a study of the microvilli. The width and height of the microvilli differed from those seen by transmission microscopy and it is suggested that these differences are related to both the shadow‐material used and the presence of a mucopolysaccharide on the surface of the membrane. The technique illustrates the possible use of fractionation methods as part of the preparative procedures in scanning electron microscopy.
An improved counting method for motile protozoan cultures
Authors: Erhan S. , Franko E. A. , Rutman R. J.
Published: August 2011

A simple counting method is described for routine cultures of highly motile organisms. It is based on dyeing the organisms with a suitable stain, filtering them through a Millipore filter and counting single organisms directly under a microscope after rendering the filter transparent.
A new technique for making plant epidermal imprints using various domestic adhesives
Authors: Inamdar J. A. , Patel R. C.
Published: August 2011

A simple, quick and easy method for making leaf surface imprints for microscopic studies by using cheap and easily available non‐toxic domestic adhesives is described. The most satisfactory results were obtained, in order of preference, by using ‘Quickfix’, ‘Stickfast’, ‘Fevicol’, ‘D.P.X. (mountant)’, ‘Camel paste’, ‘Cello‐tape’ and ‘Araldite’. These were used on the epidermis of vegetative and floral organs of a number of plants (living and dried). A semi‐transparent film was allowed to dry, which was then stripped off and mounted on a clean slide. This film records very fine structural details which are evident from the photomicrographs presented. With the help of this technique, the form, distribution and orientation of stomata, size of guard cells and their movement, size of stomatal pores, stomatal development, cell‐wall nature, stomatal frequency and indices and venation pattern can easily be studied. Repeated imprints can be made from the same surface of an organ. This method should be of great use to plant morphologists and anatomists.
An electronic light source and modified Bolex H‐16 camera for time‐lapse cinemicrography
Authors: Dawson Mary , Johnstone A. J. , Matthews J. E.
Published: August 2011

An apparatus is described for use in time‐lapse cinemicrography. The modifications made to the standard shutter mechanism of the Bolex camera offer increased reliability when it is used in a single‐frame manner over a long period. A reliable method of firing microflash tubes in synchrony with a short shutter‐opening period is also described.
Reflected‐light differential‐interference microscopy: principles, use and image interpretation
Authors: Hoffman Robert , Gross Leo
Published: August 2011

The reflected‐light differential‐interference microscope is a simple optical instrument easy to use and adjust, which reveals surface contours in variations of light intensity or in colour with a clarity and sensitivity not previously achieved. It can reveal new structures or display familiar tissue and cellular architecture in new and refreshing aspects. This type of microscope can provide insights into surface characteristics in metallurgy, microelectronics, biology, etc. Understanding how the differential‐interference microscope works, how to control it and how to interpret the images produced, is essential to using the microscope fruitfully.
Orientation of spherical specimens for ultrathin sectioning in selected planes by embedding in agar
Authors: Scott Kay , Tarin D. , Sharp J. A.
Published: August 2011

The use of agar for supporting specimens in a desired orientation during processing for electron microscopy is described.

The specimen is fixed in glutaraldehyde and orientated in liquid agar which is then allowed to set. The agar block is post‐fixed in osmium tetroxide and embedded in Araldite. Ultrathin sections are easily obtained and tissue preservation is satisfactory.
The statistical analysis of autoradiographs: II. Theoretical aspects including methods for optimal allocation of measurement effort
Authors: England J. M. , Miller R. G.
Published: August 2011

Under carefully controlled conditions autoradiographic grain densities vary in accordance with the Poisson distribution. The present paper derives several different formulæ and presents graphs to enable the experimenter to measure such grain densities to any specified accuracy after making the appropriate correction for radioactive background.

Emphasis is placed upon the allocation of counting effort between one or more labelled sources and the unlabelled background so that the total area of emulsion to be counted is minimized.

This technique of optimal measurement allocation has been considered for grain‐density measurements both by visual counting and by photometric methods.

This approach has also been applied to the problem of accurately determining the percentage of labelled cells by sampling from a large population.
Application of stereologic methods to stratified gingival epithelia*
Authors: Schroeder Hubert E. , Münzel‐Pedrazzoli Suzy
Published: August 2011

Stereologic point‐counting procedures were applied to estimate quantitative tissue and cytoplasm parameters of the oral and the junctional epithelium of the human gingiva. Three gingival biopsies of female children, obtained and processed under standardized conditions, served (1) to determine the minimal sample size of cytoplasmic area required for estimating representative volumetric parameters in different strata of both epithelia, and (2) to compare average volume and surface density data derived from standardized samples in epithelial cross sections cut at two planes orientated perpendicular to each other. Sampling of electron micrographs, performed at two levels of magnifications according to a systematic stratified random sampling procedure consisted of recording field strips parallel to the epithelial or tooth surface within each of the various strata. The optimal sample size required varied for different organelles and epithelial strata. Minimal sample size of cytoplasmic area per biopsy were 300–440 μm2 for basal, and 450 μm2 for stratum spinosum cells of oral epithelium, and 130–185 μm2 for basal cells of the junctional epithelium. Average morphometric parameters for gross tissue components (cells, nuclei, cytoplasm, intercellular space) which resulted from analysing 4900 μm2 tissue area in each of the epithelia in each biopsy, were almost identical when determined in two different section planes. Volume and surface density data of cytoplasmic organelles (mitochondria, rough and smooth endoplasmic reticulum, cytoplasmic filaments) resulting from a sample of 280 μm2 cytoplasmic area per stratum and biopsy, revealed differences of varying magnitude, when determined in the two section planes. These differences were markedly smaller than those between comparable strata of both epithelia. Discussion of sampling procedures concluded that the type of sampling used for the present study is suitable for comparative morphometric studies.
The selection of conditions for examination of specimens in a scanning electron microscope
Authors: Hearle J. W. S. , Lomas B. , Sparrow J. T.
Published: August 2011

In the past not much attention has been paid to the use of the most desirable conditions for examining a particular kind of specimen in a scanning electron microscope (SEM). The various factors affecting resolution in the SEM, namely those of beam diameter, beam penetration, contrast, signal‐to‐noise ratio and depth of focus, are examined. It is not possible in practice to eliminate all detrimental effects and compromises have to be made in instrumental settings, such as gun potential, lens currents, etc. in order to obtain the best image for a given specimen. This paper deals with the problems involved in examining textile fibres, metal surfaces and thin films with particular emphasis being made on the choice of gun potential and the amount of image detail observed. Examples are shown comparing micrographs taken using gun potentials of 5 kV and 20 kV, showing that due to electron‐penetration effects much surface detail is lost at the high gun potential. It is, therefore, useful to examine specimens initially at different accelerating voltages to determine if any desirable information is being lost due to the penetration of the electron beam. Some operating conditions are also given for use as a guideline for working at low accelerating voltages.
A technique for studying one and the same section of a cell in sequence with the light and electron microscope
Authors: Wells B. , Cour L. F. La
Published: August 2011

Methods for mounting and staining relatively thin sections on electron microscope grids, in order that one and the same section of a cell can be photographed in sequence with the light and electron microscope are described. Toluidine blue is used as a stain and hexachlorabuta‐1,3 diene as a medium which enables the grid carrying the stained sections to be temporarily mounted under a coverslip and examined with an oil‐immersion lens. Results obtained with pollen mother cells of Fritillaria lanceolata at zygotene are illustrated.
Migration of potassium out of electron‐microscope specimens
Authors: Hodson Stuart , Marshall John
Published: August 2011

We have previously reported the direct detection of sodium and potassium in ultrathin biological sections (Hodson & Marshall, 1970a) by combining the technique of ultracryotomy (Hodson & Marshall, 1970b) with an electron‐microscope probe analyser EMMA‐4 (AEI, Harlow, Essex). We also suggested that it may shortly be possible to plot intracellular concentrations of sodium and potassium if our technique was made quantitative and tested critically. During such tests on organic membranes we discovered an unexpected phenomenon: when a beam of electrons irradiates material which includes potassium, the potassium may move out of the irradiated area.
Ruthenium Red staining of ultrathin sections of human mast‐cell granules*
Authors: Kobayasi Takasi , Asboe‐Hansen Gustav
Published: August 2011

Ruthenium Red was used for staining glutaraldehyde‐fixed ultrathin sections of mast cells embedded in Epon 812. The dye was dissolved in 0.1 M ammonia, or 0.1 N acetic acid or phosphate buffer at pH 7.4, 0.1 M at a concentration of 0.5%. The ammoniacal solution stained acid mucopolysaccharides of human mast‐cell granules more specifically than did the acetic solution. The probable site of the acid mucopolysaccharides is the finely granular material within the granules.
A method for the replication of articular cartilage surfaces suitable for the scanning electron microscope
Authors: Clarke Ian C.
Published: August 2011

A method for replicating the surface of soft, wet tissue such as human articular cartilage is described. Silicone, acrylic and epoxy resins were tried. ‘Tensol‐7’ acrylic resin was found to be the most suitable replicating medium.
Preparation of human skin for high‐resolution scanning electron microscopy using phosphate buffered crude bacterial α‐amylase
Authors: Finlay J. B. , Hunter J. A. A. , Steven F. S.
Published: August 2011

A technique for preparing human skin for high‐resolution scanning electron microscopy using phosphate‐buffered crude bacterial α‐amylase is described. Effects of the buffer solution alone are studied as well as the proteolytic activity of the enzyme solution used. The biochemical implications of these observations are discussed with regard to the in situ structure of the tissue.
On the accuracy of microinterferometric measurements of optical‐path differences by means of the half‐shade method
Authors: Pluta M.
Published: August 2011

Using a shearing double‐refracting interference microscope with a half‐shade eyepiece, the accuracy of optical‐path‐difference measurements has been examined. For the half‐shade elements, birefringent strips with phase difference equal to 180°, 110° and 20° as well as a half‐wave plate with a narrow slit, cemented between two glass plates, were used. It is known that different relative intensities of the background inside and outside the half‐shade strip introduce a subjective error in the correct visual assessment of the matching point of the interference image of the object under examination. Applying test objects made of thin strips of dielectric evaporated in vacuum onto glass slides, it has been demonstrated that this error depends upon the optical‐path difference and image size of the object being measured, as well as upon the half‐shade phase difference. For a small half‐shade phase difference the error is practically imperceptible and for the half‐shade strip giving half‐wave retardation it attains maximum values. In the case of homogeneous objects, the images of which are as large as 1.5–2° in the field of view of the microscope, this error does not usually produce inaccuracies greater than ± λ/100 in optical‐path‐difference measurements. Using the half‐shade strip with a diaphragm which masks the misleading background and enables an observer to see the matched image areas only, the optical‐path difference can be measured with accuracy ± 0.003λ or better.
Some microscopical investigations of grinding and abrasive wear*
Authors: Buttery T. C. , Archard J. F.
Published: August 2011

This work forms part of a broader investigation which explores the relationship between grinding and abrasive wear. Wear experiments were performed over a wide range of loads and speeds in which solid abrasives (typical of those in grinding wheels) were rubbed against metals (usually steels). Under certain conditions the rate of wear decreased with time; at the same time the worn debris changed from metallic particles to finely divided oxides and the surface of the abrasive became glazed. Optical and scanning electron microscopy have been used to study this transition in the wear mechanism and its relationship to the structure of abrasives and the nature of abraded surfaces. The investigation illustrates the role of microscopy in the examination of a complex engineering process.
A high resolution technique for the fine‐structural localization of acid hydrolases
Authors: Bowen I. D.
Published: August 2011

An azo dye technique is described for the fine‐structural localization of acid hydrolases. Enzymatically released primary reaction product, an insoluble substituted naphthol, is coupled with ρ‐nitrobenzene diazonium‐tetrafluoborate to produce a dense particulate azo dye. Simultaneous and post‐coupling procedures are employed. The method is potentially applicable to all acid hydrolases and is free from the artifacts which beset the commonly used lead salt methods. The localization of β‐glucuronidase and acid phosphatase in rat and slug liver is specifically dealt with here. Lysosomal and cytoplasmic sources of enzyme activity are revealed.