bluuebunny/crossref_metadata_2025 huggingface dataset:
MALATE DEHYDROGENASE ISOZYMES OF THE CHICK EMBRYO
Authors: CONKLIN JAMES L. , NEBEL EDWARD J.
Published: April 2011

Malate dehydrogenase fractions of the chick embryo were demonstrated after starch gel electrophoresis of homogenates of liver, brain and spleen. A total of seven malate dehydrogenase fractions were observed to occur in the chick embryo in an organ specific pattern. Treatment of the homogenates with urea, sodium chloride-sodium phosphate, and p-chloromercuribenzoate prior to electrophoresis revealed that only three distinct malate dehydrogenase-active proteins were presence. Two of these proteins exhibited properties similar to those previously reported for the supernatant malate dehydrogenase and mitochondrial malate dehydrogenase of other species. Becuase of the differing properties of chick malate and lactate dehydrogenase it is concluded that the molecular basis for malate dehydrogenase isozymes is different from that reported for lactate dehydrogenase isozymes.
A METHOD FOR THE HISTOCHEMICAL DEMONSTRATION OF TRIPHOSPHOPYRIDINE NUCLEOTIDE-LINKED l-HEXONATE DEHYDROGENASE ACTIVITY IN KIDNEYS OF SEVERAL SPECIES
Authors: BALOGH KÁROLY
Published: April 2011

The described technique utilizes a tetrazolium salt to localize TPN2-linked l-hexonate dehydrogenase activity in unfixed frozen sections of mammalian kidneys. Enzyme diffusion was kept at a minimum by adding PVP to the incubation medium in a final concentration of 20%. Nevertheless, the sites of enzyme activity could not be localized precisely at the cell level. Histochemical evidence for l-hexonate specificity of the enzyme has been presented.

A survey of various mammalian tissues revealed strong enzyme activity in the renal cortex of hamsters, rabbits, dogs and humans. In guinea pigs, the histochemical reaction was considerably weaker in heterozygous albino males than in pigmented ones. No enzyme activity was demonstrable in any of the female guinea pigs. Otherwise, the intensity of the histochemical reaction was consistent for a particular species. Although striking species differences were seen in the enzyme distribution pattern, activity was always limited to the epithelial cells of the renal cortex. Other tissues, known to contain the enzyme, failed to reveal an unequivocal histochemical reaction.
SUGGESTIONS FOR A HISTOCHEMICAL TERMINOLOGY OF CARBOHYDRATE-RICH TISSUE COMPONENTS
Authors: SPICER S. S. , LEPPI T. J. , STOWARD P. J.
Published: April 2011

Biochemically known mucopolysaccharides can rarely be identified unequivocally in specific tisse sites by histochemical methods. Moreover, many carbohydrate-rich substances that have been detected histochemically (in terms of their vic-glycol content and characteristic acid groups) cannot be related to mucopolysaccharides and glycoproteins known to biochemists. Accordingly, a terminology and classification is proposed for delineating mucosubstances in situ in terms of their histochemical properties.

Mucosubstance and mucosaccharide are recommended as general terms for tissue entities rich in carbohydrate, but the term [acid] mucopolysaccharide is restricted to biochemically known mucopolysaccharides of connective tissue. The terms sulfomucin and sialomucin are suggested for acidic epithelial mucosubstances containing sulfate esters and sialic acid, respectively. Neutral mucosubstance is reserved for naming periodate-reactive entities, except glycogen, that lack demonstrable acid groups.

The various muscosubstances that have been found in tissue sections so far are tabulated with suggested names.
THE USE OF THIOL-SUBSTITUTED CARBOXYLIC ACIDS AS HISTOCHEMICAL SUBSTRATES
Authors: BELL MARY , BARRNETT RUSSELL J.
Published: April 2011

Thiobutyric, thiocaproic and thiocaprylic acids were synthesized, and enzyme histochemical methods were developed using these thiol-substituted carboxylic acids, as well as thiolacetic acid, as substrates with Pb++ as the capture reagent. The localization of final product of these histochemical reactions, PbS, was studied and compared in a variety of tissues with light microscopy. The enzymatic activities demonstrated were sensitive to low concentrations of E600. The localization of these reactions in several intensely reactive tissues, liver, testis and intestine, were also studied with electron microscopy. At a fine structural level, the final product was deposited primarily in relation to the membranous elements of the smooth and rough varieties of the endoplasmic reticulum, including the nuclear envelope, and of mitochondria. The results of these experiments are discussed, including the possible identity of the enzymes concerned with the hydrolysis of the thiol-substituted substrates. It was suggested that at least three activities were demonstrated in these experiments, one of which was the B type esterase of microsomes, and all of which functioned in lipid metabolism.
THE SPECIFICITY OF 5'-NUCLEOTIDASE IN THE BRAIN OF THE MOUSE
Authors: SCOTT T. G.
Published: April 2011

5'-Nucleotidase in the brain of the mouse was examined histochemically. By means of various fixatives, substrate omission, heat effects, pH variation, ionic activators and inhibitors, an antigenic inhibitor (cobra venom antiserum) and substrate specificity, it was shown that the histochemical technique is specific for 5'-nucleotidase, and that it did not depend upon non-specific phosphatases. The enzyme was also show to hydrolyze seven different mononucleotides, but not a dinucleotide, two trinucleotides nor ribose 5-phosphate. Evidence is presented that the hydrolysis of the various mononucleotide substrates may be due either to separate 5'-nucleotidases or to isoenzymes.
Organizing practices of reflection: A practice-based study
Authors: Keevers Lynne , Treleaven Lesley
Published: April 2011

This article extends debates of how organizing practices of reflexivity and collective mindfulness are encouraged and sustained for learning, critique and change. We present, in a practice-based study, a fourfold framework of anticipatory, deliberative, organizing and critically reflexive practices. Our empirical study illustrates how these multiple forms of reflexive practice can support and co-shape one another so that knowing what to do next emerges in the midst of practice. Our analysis demonstrates the value of going beyond the optical metaphor of reflection to that of critical reflexivity and the metaphor of diffraction. This approach extends understandings of reflective practice in ways that foreground entanglement, co-production and the relational qualities of practice. Diffraction encourages managers and practitioners to not only reflect on what has been done but to also map the effects of their practices and interventions. This orientation assists them to notice the impact of their actions and better understand the complexities of organized reflection-in-action.
Sex differences in cognitive domains and their clinical correlates in higher-functioning autism spectrum disorders
Authors: Bölte Sven , Duketis Eftichia , Poustka Fritz , Holtmann Martin
Published: April 2011

Despite the skewed sex ratio, few studies have addressed possible cognitive sex differences in autism spectrum disorders (ASDs). This study compared visual attention to detail (ATTD) and selected executive functions (EF) in 35 males and 21 females with higher-functioning ASD and unaffected sibling controls. Females with ASD outperformed males on EF as assessed by the Trail Making Test B-A. Males with ASD showed superior performance for ATTD as measured by the Block Design Test (BD) when compared with females. EF difficulties in males were correlated with more stereotypic behaviours and interests on the Autism Diagnostic Interview-Revised or the Autism Diagnostic Observation Schedule. The results indicated clinically meaningful cognitive sex differences in ASD, particularly an association between EF and stereotypic behaviours and interests. ATTD as a potential basis for specific cognitive strengths (e.g. scientific/savant skills) might be more pronounced in males with ASD.
Experienced teachers and school reform: Exploring how two different professional communities facilitated and complicated change
Authors: Levine Thomas H
Published: April 2011

Scholars have proposed that ‘the path to change in the classroom lies within and through’ more collaborative professional communities among teachers (McLaughlin and Talbert, 1993: 18). How do different approaches to developing collaborative professional communities impact experienced teachers and their ability to change? This article identifies differences between ‘teacher professional communities’ and ‘professional learning communities’. It then presents two case studies to explore the implications of these differences for experienced teachers engaged in school reform. Interview and observational data from two sites suggest that schools which nurture collaborative ‘teacher professional communities’ over time can create resources that help experienced teachers to change aspects of their work. Such resources include: norms promoting innovation; widely shared objectives; trust; continuity with the past; respect for experienced teachers; and traditions promoting morale. Schools that rapidly engineer a ‘professional learning community’ may lack such resources, reducing experienced teachers’ willingness and ability to change.
A school intervention to increase prosocial behavior and improve academic performance of at-risk students
Authors: Kilian Janet M , Kilian Denis W
Published: April 2011

The purpose of this pilot study was to investigate an intervention for at-risk elementary school students who did not respond sufficiently to a universal school-wide social skills program. The manualized social skills counseling intervention was implemented for two years, and sought to create and maintain appropriate student relating and problem solving, and to improve academic performance. The effectiveness of the intervention was determined using measures of behavior, grades, standardized tests, and need for special services collected pre- and post-intervention for individual students, the intervention group and a comparison group. Results suggest substantial positive intervention outcomes across multiple variables for individual students and between groups. Implications of this field based study are considered in terms of applied school practice.
HISTONE SPECIFICITY REVEALED BY AMMONIACAL SILVER STAINING
Authors: BLACK MAURICE M. , ANSLEY HUIDSON R.
Published: April 2011

Post-formalin ammoniacal-silver, a staining method which is selective for histone, imparts different colors, ranging from yellowish to black, to many different cell types. The same colors are imparted to histone extracts of the cell types in question. Pure lysine as well as so-called lysine-rich histone subfractions stain yellowish, while pure arginine and so-called arginine-rich subfractions stain black. The mechanism of the color differences of the stain is somewhat elucidated by these findings, and the study of histone specificity facilitated.
CYTOCHEMISTRY OF CYTOPLASMIC AND INTRANUCLEAR INCLUSIONS INDUCED BY BOVINE PARAINFLUENZA 3 VIRUS (SF-4) IN HUMAN CELL CULTURES
Authors: KASTEN FREDERICK H. , CHURCHILL A. E.
Published: April 2011

Infection of human IIEp-2 cells with myxovirus bovine parainfluenza 3 (SF-4) induces the formation of cytoplasmic and intranuclear inclusions. Both types of inclusions were shown to contain some RNA in late stages (gallocyanin chromalum, azure B bromide, pyronin, RNase), abundant protein at all stages (acidic fast green, mercuric bromphenol blue) primarily with lysine-rich residues (naphthol yellow S, lysine blockage) and lesser amounts of arginine (Sakaguchi) and tyrosine (diazotization coupling). Inclusions failed to stain for histones (alkaline fast green, ammoniacal silver), basic proteins (alkaline Biebrich scarlet, picric acid-eosin). DNA (Feulgen, fluorescent-Feulgen, methyl green, gallocyanin chromalum, azure B bromide) and polysaccharides (fluorescent-PAS, Hale). There was a slight staining for histones with metaphosphoric acid-gallocyanin and basic proteins with picric acid-bromphenol blue or -eosin and a negative reaction for proteins with the fluorescent modification of the N-Bromosuccinimide-Schiff reaction. Acridine orange fluorochroming revealed a false positive reaction for DNA (green fluorescence) which was due to protein.
XANTHINE OXIDASE FROM LIVER AND DUODENUM OF THE RAT: HISTOCHEMICAL LOCALIZATION AND ELECTROPHORETIC HETEROGENEITY
Authors: SACKLER MURIEL LAZARUS
Published: April 2011

A comparative study of xanthine oxidase in rat duodenum and liver was carried out by a histochemical technique, by cell fractionation and zone electrophoresis. With the histochemical method presented, reaction product could be demonstrated in the epithelial cells of the duodenal villi in glutaraldehyde-fixed cryostat sections incubated in 0.2 M sodium phosphate buffer at pH 7.4 containing 2.5 x 10-3 M hypoxanthine and 1 mg/ml nitro-blue tetrazolium (Nitro-BT). No reaction product could be observed, however, in similarly treated sections of rat liver. Liver and duodenal homogenates showed high enzyme activity when assayed by a microfluorometric method using 2-amino-4-hydroxy pteridine as substrate. Fractionation of these homogenates revealed the presence of enzyme activity only in the high speed supernatant fraction. This fraction was also studied by zone electrophoresis on vertical starch gel and by acrylamide gel, disc electrophoresis. Xanthine oxidase separated electrophoretically into two distinct bands and was localized by incubation of the gels in the same medium as described for the histochemical method. The duodenal enzyme showed a more rapid mobility than that of the liver. The inability to demonstrate the hepatic enzyme histochemically is believed to depend on the lower concentration of the enzyme in liver as compared with its concentration in the duodenal mucosa.
SUITABILITY OF COLLAGENASE TREATMENT FOR THE RADIOAUTOGRAPHIC IDENTIFICATION OF NEWLY SYNTHESIZED COLLAGEN LABELED WITH H-GLYCINE OR H-PROLINE
Authors: CARNEIRO J. , LEBLOND C. P.
Published: April 2011

Sections of Carnoy-fixed tissues from young rats and adult mice were incubated for 5 hr at 37°C in a 0.1% solution of Clostridium histolyticum collagenase purified by ion exchange chromatography. This treatment causes collagenous fibers as well as dentinal and bone matrices to lose their ability to stain red with the van Gieson technique and pink with eosin. In view of the high specificity of the enzyme, it is assumed that the stained component of these tissues is collagen. Immediately after injection of 3H-glycine or 3H-proline, radioautography shows the label in the cytoplasm of several cell types: osteoblasts of femur and alveolar bone, odontoblasts of growing molar and incisor teeth. and fibroblasts of the periodontal membrane. Later, the label appears outside the cells, that is, in bone matrix, dentinal matrix and intercellular spaces of periodontal membrane, respectively. Collagenase treatment extracts about half of the label which is present in the cells soon after injection, all or nearly all the label which appears later in bone and dentinal matrix, but only a fraction of that which appears in the intercellular spaces of the periodontal membrane. It is concluded that the radioactivity which occurs in osteoblasts, odontoblasts and some fibroblasts soon after injection of 3H-glycine and 3H-proline is composed in about equal parts of collagen and of other protein(s). In bone and dentinal matrix collagen alone seems to be deposited, whereas in the periodontal membrane collagen is laid down in association with other protein(s).
THE ULTRASTRUCTURAL LOCALIZATION OF CHOLINESTERASE ACTIVITY IN THE SCIATIC NERVE OF THE RAT
Authors: SCHLAEPFER WILLIAM W. , TORACK RICHARD M.
Published: April 2011

Ultrastructural localization of cholinesterase activity was demonstrated in rat sciatic nerve using thiocholine esters as substrate. This enzymatic activity was limited to axons, where it was located on limiting axonal membranes, and on axonal vesicles of all unmyelinated and some myelinated nerve fibers. No accentuation of activity was present at nodes of Ranvier. The use of acetyl, propionyl and butyrylthiocholine as substrate resulted in decreasing amounts of end product precipitate, respectively. The cholinesterase activity was sensitive to heat, resistant to N-ethyl maleimide, and inhibited byeserine, DFP, E600, RO2-1250 and BW 62C47. Studies of specific inhibition sensitivities and substrate preferences suggested that the axonal cholinesterase of rat sciatic nerve is a specific acetylcholinesterase which is relatively homogeneous.
THE DEVELOPMENT OF LYSOSOMES IN RAT SKELETAL MUSCLE IN TRICHINOUS MYOSITIS
Authors: MAEIR DAVID M. , ZAIMAN HERMAN
Published: April 2011

Rat striated muscle (gastroenemius) containing encysted Trichinella larvae was studied histochemically for hydrolases associated with lysosomes. Activity of the enzymes studied (acid phosphatase, esterase, aminopeptidase), not demonstrable in appreciable amounts in normal striated muscle, appears in the altered muscle fibers in granules which by various criteria are demonstrated to be lysosomes. The increase in lysosomal enzyme activity is accompanied by increased prominence of the Golgi apparatus, as demonstrated by thiamine pyrophosphatase activity, and by an increase in the ribonucleoprotein content of the muscle fibers. These changes illustrate the facultative development of lysosomes and their associated ferments during a regenerative process. They suggest the need for a revision of the classic concept of the primarily degenerative nature of the trichinous lesion as well as a possible role of the developing lysosomes in this process.
RESOLVING POWER, SENSITIVITY AND LATENT IMAGE FADING OF SOLUBLE-COMPOUND AUTORADIOGRAPHS
Authors: APPLETON T. C.
Published: April 2011

The resolving power, sensitivity and latent image fading have been studied in autoradiographs prepared by a technique that retains soluble compounds. A resolution of 2-4 µ was obtained in preparations containing 3H-thymidine and 9-13 µ in those containing 22NaCl. Results showed that there was no significant diffusion of soluble compounds. Sensitivity studies revealed that –25°C was the optimum exposure temperature. There was no significant latent image fading in preparations exposed for periods up to 330 days.
RENAL LOCALIZATION OF TRITIATED STREPTOCOCCAL POLYPEPTIDE
Authors: WILLIAMSON C. K. , ELLIOTT S. C.
Published: April 2011

Certain strains of Streptococcus pyogenes, Type 12 elaborate a polypeptide which is nephritogenic in experimental animals. It appeared to be a pure, nonmigrating component by paper chromatography, to be electrophoretically pure when analyzed by the Spinco electrophoretic system, and to be homogeneous by ultracentrifugal analysis. Quantitative amino acid analyses of acid-hydrolyzed samples revealed 19 amino acids and trace amounts of five unidentified components. Glycine, proline, alanine, glutamic acid and aspartic acid accounted for 70% of the amino acids found. Wilzbach tritiated samples were injected intraperitoneally into 20-g C57B1 male mice. Radioautographic evidence revealed that a high percentage of the injected material concentrated in renal tissue.
QUANTITATIVE DISTRIBUTION OF LACTIC DEHYDROGENASE IN THE REGENERATING LIVER LOBULE OF THE RAT
Authors: THALER MANNING MICHAEL , KISSANE JOHN M. , WILSON WILLIAM
Published: April 2011

Regeneration of rat liver is maximal during the first day following partial hepatectomy. In order to obtain quantitative data on lactic dehydrogenase during this period of increased energy utilization, microdissection of lobules at 0, 15 and 30 hr after partial hepatectomy was carried out. Isolated samples from periportal, midzone and pericentral areas weighing 0.05-0.2 µg, dry weight, were analyzed for LDH and DNA. Sections were also stained for glycogen, fat and LDH. Qualitative results revealed depletion of glycogen from portal and midzonal regions, accumulation of fat in periportal zones, and heavier concentrations of LDH in peripheral areas of the regenerating lobule. Quantitative analysis showed LDH activity to be 40-50% higher in peripheral compared to central zones. Similar levels and relative concentrations of enzyme persisted throughout the 30-hr regenerative period investigated. DNA content increased by about 30% in the peripheral zone during the same period. The possible meaning of these findings is discussed.
EFFECT OF EDTA ON HISTOCHEMICAL DEMONSTRATION OF PHOSPHORYLASE ACTIVITY
Authors: HORI SAMUEL H.
Published: April 2011

Effects of ethylenediaminetetraacetate on the phosphorylase activity were studied histochemically and biochemically; sections were incubated in a variety of media with or without EDTA, and stained by I2-KI solution and periodic acid-Schiff reagent for the demonstration of synthesized and total glycogen, respectively. Incubated sections and the substrate media used for the incubation were also assayed for glycogen by the anthrone method. Both qualitative and qualitative data showed that EDTA stimulated greatly the synthesis of glycogen from glucose 1-phosphate in sections, and markedly reduced the degradation of glycogen present in sections, which otherwise occurred following incubation in acetate buffer. Other chelating agents, such as 1,2-cyclohexane diamine tetraacetic acid, diethylene triamine pentaacetic acid, nitrilotriacetic acid and glycolether diamine tetraacetic acid, failed to replace for EDTA in the phosphorylase staining. On the other hand, only 1,2-cyclohexane diamine tetraacetic acid inhibited glycogen degradation similarly to EDTA. The stimulative effect of EDTA on the phosphorylase staining might be explained by inhibition of hepatic α-amylase and activation of phosphorylase. Celloidine coating and subsequent treatment of sections with cold 30% ethanol enhanced the phosphorylase staining. Addition of adenosine 5'-phosphoric acid to the substrate medium did not significantly stimulate the enzyme activity.
DRY WEIGHT DETERMINATION OF SINGLE LYOPHILIZED MAST CELLS OF THE RAT
Authors: DIAMANT BERTIL , LOWRY O. H.
Published: April 2011

Dry weight and fat-free dry weight determinations are presented for single lyophilized rat peritoneal mast cells together with an average value for the protein content. By combining these results with values in the literature for heparin, histamine and serotonin, it is possible to account for most of the dry weight of rat mast cells.
A QUANTITATIVE AND HISTOCHEMICAL STUDY OF PHOSPHORYLASE IN THE PLACENTA
Authors: GRILLO T. ADESANYA IGE
Published: April 2011

A quantitative and histochemical study of phosphorylase has been made in the human, rat and rabbit placentae. The placental enzyme was found to have the same optimal pH as liver phosphorylase. Since cyclic 3',5'-AMP, glucagon or adrenaline had no influence on enzyme activity, phosphorylase probably exists only in the active form in the placenta. The activity of phosphorylase was localized histochemically in the decidua basalis, the cytotrophoblast of the spongy zone of the chorioallantoic placenta and in the visceral layer of the inverted yolk sac of the rat. It was present mainly in the decidua basalis of placenta of the rabbit although a few cytotrophoblastic cells of the trophoblastic tubules also showed weak activity. In the human placenta the enzyme was active in the cytotrophoblast and the mesodermal core of the villi. It was present occasionally in the syncytiotrophoblast. The quantity of the enzyme fluctuates during gestation in both the human and rat fetal placentae. These fluctuations do not appear to bear relation to either placental glycogen level or to fetal liver phosphorylase activity. Nor is there any obvious correlation between placental phosphorylase and the activity of glucagon-like substance of the fetal pancreas.
FEULGEN HYDROLYSIS: EFFECT OF ACID AND TEMPERATURE
Authors: DECOSSE JEROME J. , AIELLO NANCY
Published: April 2011

Two methods of Feulgen hydrolysis (5.0 N HCl at room temperature and 1.0. N HCl at 60°C) were examined by serial microspectrophotometric measurements of the relative DNA content of normal human lymphocytes subjected to each hydrolysis. The DNA contents at optimum hydrolysis were equal by both methods. Hydrolysis in 5.0 N HCl at room temperature resulted in an interval of 120 min of stable peak values. Successive hydrolyses to the optimum time, as defined for each methtod in the initial experiment, indicated that hydrolysis 5.0. N HCl at room temperature provided a more reliable technique. The results also suggested that depurination is dependent primarily on acid rather than heat, while further degradation is dependent primarily on heat rather than acid.
CHARACTERIZATION OF ENZYMES HYDROLYZING ACYL NAPHTHYLAMIDES III. ROLE OF KYNURENINE FORMAMIDASE
Authors: HOPSU V. K. , SANTTI R. , GLENNER G. G.
Published: April 2011

An enzyme fraction in guinea pig liver catalyzing the hydrolysis of chloroacetyl α-naphthylamide was separated by gel filtration and demonstrated to hydrolyze N-formyl- l-kynurenine. On the basis of relative substrate hydrolysis rates, the enzymes in this peak were shown to have the characteristics of kynurenine formamidase, an enzyme catalyzing the transformation of N-formyl- l-kynurenine to l-kynurenine and formic acid. The histochemical localization in fixed tissue of the hydrolysis of chloroacetyl α-naphthylamide can be almost totally ascribed to this enzyme and, thereby, indicates tissue sites of tryptophan catabolism.
SUBFRACTIONS OF LACTATE DEHYDROGENASE OF THE RAT
Authors: BUTA JANET L. , CONKLIN JAMES L. , DEWEY MAYNARD M.
Published: April 2011

A survey of the lactate dehydrogenase (LDH) isozymes of 20 organs and tissues of the rat revealed a total of nine fractions exhibiting LDH activity after starch gel electrophoresis. Of the nine LDH fractions, eight were found in testis and lymph node, while the ninth fraction was unique to kidney. The occurrence of LDH fractions in excess of the usual five LDH isozymes is accounted for by two alternate proposals. One proposal is an extension of the present tetramer postulate of LDH structure, while the other is a consideration of the significance of heterozygosity in the albino rats employed in the study. Both hypotheses are plausible and should be considered in future studies of isozymes.
TISSUE FIXATION BY DIAZONIUM SALTS OF A PARTICLE-BOUND RAT KIDNEY AMINOPEPTIDASE
Authors: NAGATSU I. , MASON S. , GLENNER G. G.
Published: April 2011

Several rapid coupling diazonium salts (fast garnet GBC, fast red B and fast blue R) have been shown to cause the retention by fixation in tissue sections of the buffer-extractable portion of a particle-bound aminopeptidase catalyzing the hydrolysis of l-leucyl β-naphthylamide. The enzyme retained by these diazonium salts is identical to a cobalt-activated aminopeptidase which remains bound to tissues after buffer washing, but is distinct from a soluble sulfhydryl-dependent aminoptipedase extracted from tissues during incubation. No one of the three diazonium salts tested at equivalent coupling concentrations produced more retention of enzyme in tissue section than another, while the surfactants and salts present in commercial garnet GBC had no discernible effect in preventing enzyme extraction.
Unrestricted student blogging: Implications for active learning in a virtual text-based environment
Authors: Deed Craig , Edwards Anthony
Published: April 2011

Realizing the potential for web-based communication provides a challenge for educators. The purpose here is to report students’ behavioural and cognitive strategies for active learning when using an unrestricted blog in an academic context. This provides insight into how students are making sense of the incorporation of Web 2.0 technology into higher education. An analytical framework was created to investigate the willingness and competence of students to engage in the social and virtual construction of knowledge. The analysis indicated that, while the students appear to have wanted to complete the task efficiently, the process of critically constructing knowledge was not pursued with vigour. The main implication is therefore that students need to either prepare themselves or be prepared by educators to combine their informal experience of communication technology with academic requirements for actively constructing knowledge in virtual environments.
Using Flip camcorders for active classroom metacognitive reflection
Authors: Hargis Jace , Marotta Sebastian M.
Published: April 2011

A Center for Teaching and Learning provided Flip camcorders to a group of 10 new faculty members, who were asked to use this teaching tool in their classroom instruction. The classes included mathematics, political science, computer engineering, psychology, business, music and dance. The qualitative results indicate that all faculty members and many students enjoyed the experience. Faculty identified innovative methods to integrate the camera into their classroom teaching, which resulted in more engagement and positive student outcomes. Several faculty members developed methods, procedures, assessment rubrics and guidelines for using the Flip in assignments. The major finding may be the breadth of generalizability for the use of this tool across disciplines for increasing student engagement. The primary goal of this research is to provide data on one of many emerging technology tools to help faculty exploring potential devices for continued improvement and understanding of how we learn.
Co-construction of management concepts: Interpretative viability as opportunity for workplace democracy
Authors: Rolfsen Monica
Published: April 2011

When management concepts are introduced in organizations, common problems are lack of enthusiasm and that the concept does not solve the organization’s problems. In this article, I argue that a more participative process is to introduce new ideas through broad participation and dialogue between insiders and outsiders in order to increase the level of industrial democracy. However, to be able to do so, the management concept has to be flexible enough to be able to be interpreted in different ways. Dialogue and participation require the actual opportunity to make changes to the original concepts. Most management concepts, however, are inherently flexible by being characterized by interpretative viability. This viability opens up an opportunity for participation. In this article, I will describe a case where such an opportunity was used.
REUTILIZATION OF MATERNAL NUCLEAR MATERIAL BY EMBRYONIC AND TROPHOBLASTIC CELLS IN THE RAT FOR THE SYNTHESIS OF DEOXYRIBONUCLEIC ACID
Authors: GALASSI LEONE
Published: April 2011

Normal blastocysts were transferred to the uteri of rats previously injected systemically with thymidine-3H. Autoradiography of the 9th day implantation sites showed that the embryo, the yolk sac and the ectoplacental cone were lightly labeled because of reutilization of thymidine-3H from the maternal circulation. The giant trophoblastic cells were as heavily labeled as the uterine cells. After transplantation of normal blastocysts to uteri previously injected locally with thymidine-3H, a number of giant trophoblastic cells were found labeled. No radioactivity was present on other embryonic structures. The conclusion was reached that the embryo does not utilize for its deoxyribonucleic acid synthesis nucleosides or nucleotides from the uterine "histotroph." The giant cells, instead, appear to incorporate a substantial amount of label in the form of macromolecular deoxyribonucleic acid.
HISTOCHEMICAL METHODS FOR SEPARATE, CONSECUTIVE AND SIMULTANEOUS DEMONSTRATION OF ACETYLCHOLINESTERASE AND NOREPINEPHRINE IN CRYOSTAT SECTIONS
Authors: EL-BADAWI AHMAD , SCHENK ERIC A.
Published: April 2011

Techniques for the separate, consecutive and simultaneous demonstration of acetylcholinesterase and norepinephrine in cryostat sections are described and discussed. The results, obtained in a variety of tissues from different animal species, are as satisfactory—in terms of sensitivity and sharpness of localization—as those obtained by previously described methods. The simultaneous visualization of both acetylcholinesterase and norepinephrine in the same section provides hitherto unavailable data relative to the exact interrelationship of cholinergic and adrenergic components of the peripheral autonomic nervous system.
A STABLE HISTOCHEMICAL GMELIN REACTION OF BILE PIGMENTS WITH DRY BROMINE-CARBON TETRACHLORIDE SOLUTION
Authors: LILLIE R. D. , PIZZOLATO PHILIP
Published: April 2011

Treatment of bile pigments of tissue sections with dry solutions of bromine in carbon tetrachloride (0.5%, v/v) for intervals of 10-90 min produces a range of colors from very dark violet or red purple through lighter shades to pale rose pink or yellowish pink. Preparations may be mounted in xylene cellulose caprate and colors remain demonstrable for some weeks, although with some fading. The reaction is regarded chemically as equivalent to the traditional Gmelin reaction and offers an additional identification reaction for these pigments. Some samples of hematoidin also react, but repeated application of the test may be needed.
STUDIES ON ALKALINE AND ACID RIBONUCLEASES IN MAMMALIAN TISSUES IMMUNOHISTOCHEMICAL LOCALIZATION AND IMMUNOCHEMICAL PROPERTIES
Authors: MORIKAWA SHIGERU
Published: April 2011

The distribution of alkaline and acid ribonucleases (RNases) was investigated in bovine tissues using fluorescent antibody techniques. The immunochemical properties of the bovine RNases were also examined. Specific antibodies against acid and alkaline RNase obtained by immunizing rabbits with the corresponding antigens were conjugated with fluorescein isothiocyanate or tetramethylrhodamine isothiocyanate. Anti-alkaline RNase antibody reacted against alkaline RNase-A, and anti-acid RNase antibody reacted against two different acid RNases with no cross-reactivity between alkaline and acid RNases. Phosphate-buffered 10% formalin was the best general fixative among those examined, but some differences in staining results were observed depending upon the tissue and fixative employed. Two different patterns of distribution of alkaline RNase in pancreas and kidney were observed depending upon the fixative employed. The localization of RNases in bovine pancreas, liver, small intestine, kidney, spleen, lymph node, thymus, adrenal and heart were investigated and the physiologic roles of the RNases were discussed.
A THIOCHOLINE-LEAD FERROCYANIDE METHOD FOR ACETYLCHOLINESTERASE
Authors: ERANKÖ OLAVI , KOELLE GEORGE B. , RÄISÄNEN LIISA
Published: April 2011

The principle employed in the thiocholine-copper ferrocyanide method of Karnovsky and Roots has been adopted for the development of a similar procedure in which lead, complexed with Tris-acetate buffer, is used as the trapping agent for the ferrocyanide ion, formed by the preferential reduction of ferricyanide by thiocholine released enzymatically from acetylthiocholine. The resulting colloidal, faintly yellowish white precipitate, Pb2Fe(CN)6, can be viewed directly by light or phase contrast microscopy, or more easily following its conversion to PbS. The method has been shown to produce extremely fine localization of acetylcholinesterase in the cat superior cervical and stellate ganglia and at the motor end plates of mouse intercostal muscle.
PEPSIN DIGESTION OF VIRUS PARTICLES IN CANINE HEPATITIS USING EPON-EMBEDDED MATERIAL
Authors: GIVAN KATHLEEN F. , TURNBULL CHARLOTTE , JÉZÉQUEL ANNE-MARIE
Published: April 2011

Sixteen-week-old dogs were inoculated with 20,000 tissue culture doses (TCD50) of infectious canine hepatitis virus. Four days after inoculation, liver cells examined in the electron microscope contained both virus particles and nonviral paracrystalline formations. Tissue culture cells also contained virus particles and nonviral paracrystalline formations 48 hr after inoculation with virus. When Epon-embedded sections were treated for 1 hr with 0.5% pepsin in 0.1 N HCl, a selective extraction of the viral coats and of the nonviral paracrystals was observed.
QUANTITATIVE DETERMINATION OF ENZYMES IN DIFFERENT PARTS OF THE VILLI AND CRYPTS OF RAT SMALL INTESTINE COMPARISON OF ALKALINE PHOSPHATASE, DISACCHARIDASES AND DIPEPTIDASES
Authors: NORDSTRÖM CHRISTER , DAHLQVIST ARNE , JOSEFSSON LARS
Published: April 2011

By horizontal sectioning of a fresh frozen piece of rat intestinal wall different parts of the villi and the crypts were isolated. Every third serial section was taken for histologic examination and the intermediate sections were combined in pairs, homogenized and used for enzyme analysis. A quantitative comparison of the distribution of alkaline phosphatase, EC 3.1.3.1, disaccharidase, EC 3.2.1 (maltase, invertase, isomaltase, trehalase, lactase and cellobiase), and dipeptidase, EC 3.4.3 (L-alanyl-L-proline dipeptidase, L-alanyl-L-glutamic acid dipeptidase and glycyl-L-leucine dipeptidase), activities was performed. All of the enzymes were present in the villi and absent from the crypts. The disaccharidase and dipeptidase activities showed a rather similar distribution. The highest activities were found in the apical halves of the villi. The alkaline phosphatase activity was more distinctly located in the tips of the villi.
FINE STRUCTURE OBSERVATIONS OF THE UPTAKE OF INTRAVENOUSLY INJECTED PEROXIDASE BY THE RAT CHOROID PLEXUS
Authors: BECKER NORWIN H. , NOVIKOFF ALEX B. , ZIMMERMAN H. M.
Published: April 2011

The uptake by the choroid plexus of adult rats of intravenously injected horseradish peroxidase has been investigated by electron microscopy. Within 4 min, the injected protein passes the capillary and is rapidly distributed through extracellular space and choroidal cells. Peroxidase enters the choroidal cells within coated vesicles which act as pinocytotic vesicles. At 15 min, peroxidase activity is present in numerous membrane-bound vesicles, multivesicular bodies, dense bodies and what appear to be segments of smooth endoplasmic reticulum. None of the peroxidase-containing organelles is seen to empty to the ventricular surface. Egress of the extracellular peroxidase into the cerebrospinal fluid is apparently blocked by apical zonulae occludentes between the choroidal cells.
HISTOCHEMICAL INVESTIGATIONS ON THE IN VIVO EFFECTS OF FLUORIDE ON TRICARBOXYLIC ACID CYCLE DEHYDROGENASES FROM PELARGONIUM ZONALE: PART II
Authors: LOVELACE C. JAMES , MILLER GENE W.
Published: April 2011

In vivo effects of fluoride on tricarboxylic acid (TCA) cycle dehydrogenase enzymes of Pelargonium zonale were studied using p-nitro blue tetrazoleum chloride. Plants were exposed to 17 ppb HF, and enzyme activities in treated plants were compared to those in controls. Leaves of control plants were incubated in 5 x 10–3 M sodium fluoride. Injuries observed in fumigation and solution experiments were similar. Leaf tissue subjected to HF or sodium fluoride evidenced less succinic p-nitro blue tetrazoleum reductase activity than did control tissue. Other TCA cycle dehydrogenase enzymes were not observably affected by the fluoride concentrations used in these experiments. Excised leaves cultured in 5 x 10–3 M sodium fluoride exhibited less succinic p-nitro blue tetrazoleum reductase activity after 24 hr than did leaves cultured in 5 x 10–3 M sodium chloride.
THE EFFECT OF COENZYME Q ON THE HISTOCHEMICAL SUCCINIC TETRAZOLIUM REDUCTASE REACTION: A HISTOCHEMICAL STUDY
Authors: HORWITZ CHARLES A. , BENITEZ LUIS , BRAY MARGARET
Published: April 2011

The role played by coenzyme Q (CoQ) in the succinic tetrazolium reductase reaction was investigated. Fresh cryostat sections of normal rat tissues were extracted with acetone to remove CoQ from the tissue sections and the acetone-extracted sections were reconstituted with CoQ-lecithin complexes. The incubation film method for tetrazolium reductases was used as a test system, using succinate as a substrate. Sections from which CoQ had been selectively extracted did not reduce the tetrazolium to its formazan, whereas those acetone-extracted sections that were treated with CoQ-lecithin complexes or with the electron carrier phenazine methosulfate reacted positively. It was concluded that the succinic tetrazolium reductase reaction requires intermediate electron carriers, mainly CoQ. It follows that nitro blue tetrazolium cannot accept electrons directly from the flavins. Therefore, the tetrazolium reductase reaction depends not only on the amount of succinic dehydrogenase and flavins but also on the amount of CoQ in the tissue.
ULTRASTRUCTURAL LOCALIZATION OF Mg++-DEPENDENT DINITROPHENOL-STIMULATED ADENOSINE TRIPHOSPHATASE IN HUMAN BLOOD PLATELETS
Authors: VETHAMANY VICTOR G. , LAZARUS SYDNEY S.
Published: April 2011

Fine structural localization of adenosine triphosphatase activity was studied in human platelets briefly fixed in cold formol calcium and then incubated in lead medium with added dinitrophenol. Under these conditions, the Mg++-dependent dinitrophenol-stimulated adenosine triphosphatase of platelet mitochondria was demonstrated, but neither granules nor plasma membrane showed enzyme activity.
HISTOCHEMICAL OBSERVATIONS OF THE ENZYMATIC HYDROLYSIS OF GELATIN FILMS
Authors: CUNNINGHAM LEW
Published: April 2011

Sections of rat organs were incubated upon gelatin films to which an azo dye had been attached. The films were dissolved at points where they were attacked by enzymes released by renal proximal convoluted tubules, thyroid follicular epithelium, serous tubules of the submandibular gland and macrophages. These structures could be identified by staining the sections as they lay upon the films. The resolution was sufficient to permit identification of individual active cells. The proximal tubule enzyme had a pH optimum of 4.4, had no essential sulfhydryl group and was active in the presence of a chelating agent.
AN INVESTIGATION OF THE ROLE OF PLANT PEROXIDASE IN CELL WALL DEVELOPMENT BY THE HISTOCHEMICAL METHOD
Authors: DE JONG DONALD W.
Published: April 2011

Peroxidase localization is cytoplasmic in juvenile onion root tissues and associated with the walls in mature cells. The enzyme reaction is strongest in tissues which do not lignify, but is wholly absent in the lignifying xylem throughout all stages of development. One wall surface—the cortical-endodermal junction—exhibits a thermostable, cyanide-insensitive peroxidase reaction. This "pseudoperoxidase" is located at a site which stains most heavily for pectic material. Phenolic deposition occurs at the opposite wall surface in the endodermal cell. The reciprocal interaction observed between peroxidase enzyme and the plant growth hormone, indoleacetic acid, is not compatible with the concept that plant peroxidase is identical with indoleacetic acid-oxidase. Although auxin treatment changes the pattern of peroxidase localization in cell walls, the accumulation of hormone is greatest in hypodermal cells which are strongly positive for peroxidase. A mutual exclusion phenomenon observed for peroxidase and sulfhydryl proteins localized in the cells of young root tissues does not persist into the mature tissues where these two reactions can occur at the same wall sites. The data do not support the theory that plant peroxidase is involved in cell wall synthesis. Its occurrence in conjunction with cell wall fractions may be incidental and only indirectly related to the natural redox function of the enzyme.
DETERMINATION OF HISTIDINE DECARBOXYLASE IN MICROGRAM SAMPLES OF TISSUE, PROPERTIES AND QUANTITATIVE HISTOCHEMISTRY OF THE ENZYME AND HISTAMINE IN THE RAT STOMACH
Authors: KIM YOUNG S. , GLICK DAVID
Published: April 2011

Properties of histidine decarboxylase of rat stomach were studied, including measurements of the Michaelis constant and effects of pH. Optimal conditions for determination of the enzyme were established. A method for this determination on microgram samples of tissue, e.g., microtome sections, that depends on fluorometric analysis of nanogram amounts of histamine, was elaborated and applied to a preliminary investigation of the quantitative histologic distribution of histidine decarboxylase in the body of the glandular stomach of the rat. A parallel study of the quantitative distribution of histamine was also made, and both it and the enzyme activity were predominantly concentrated in the chief cell region. From analysis of gross homogenates, the body of the stomach was found to have greater concentrations of histamine and enzyme activity than the antrum. The findings obtained were considered in relation to distribution of mast cells and acid secretion.
CHANGES IN INTRACELLULAR LOCATION OF SMALL PHAGOSOMES (MICROPINOCYTIC VESICLES) IN KIDNEY AND LIVER CELLS IN RELATION TO TIME AFTER INJECTION AND DOSE OF HORSERADISH PEROXIDASE
Authors: STRAUS WERNER
Published: April 2011

The change in location of small phagosomes containing ingested horseradish peroxidase was investigated as a function of time after injection and dose. A spread of small phagosomes from the apical toward the basal poles was observed in the tubule cells of the kidney during the first 30 min after injection of peroxidase. In the proximal convoluted tubule cells, many small phagosomes were seen lying close to lysosomes, 15-30 min after protein injection, probably preceding fusion. Small phagosomes almost disappeared from the cells when their fusion with lysosomes was completed. In the distal tubule cells the, main transport of peroxidase occurred between the apical and basal regions, and only a minor part was transported to lysosomes. At greatly reduced loads, the cells of the proximal convoluted tubules and large collecting tubules continued to absorb the protein but peroxidase transport across the distal tubule cells was abolished. Phagosomes in glomerular epithelial cells were observed only when optimal conditions of fixation were applied. In the liver, most of the peroxidase accumulated in small phagosomes of lining endothelial cells. A new formation of lysosomes in these cells seemed to take place in relation to the digestion of peroxidase, suggesting the transformation of endothelial cells into Kupffer cells. Peroxidase was also transported across the liver cells and appeared in pericanalicular granules.
PRELIMINARY ATTEMPTS AT ULTRASTRUCTURAL POLYSACCHARIDE LOCALIZATION IN ROOT TIP CELLS
Authors: PICKETT-HEAPS J. D.
Published: April 2011

A basic method and many variations are described which initially appear to give good ultrastructural localization of polysaccharide material and also sulfhydryl groups in sections of plant tissues. Using permanganate fixation, alkaline silver hexamine solutions very strongly stained cell walls and starch grains (if they survived the treatment) in thin sections; in root cap and epidermal cells, Golgi bodies and associated vesicles also strongly reacted. The reaction was markedly reduced if sections were pretreated with aldehyde-complexing reagents (dimedone, etc.) and reintroduced after such blocking reactions by further periodate oxidation. Apart from a variable unspecific argentophilic reaction of manganese in the sections (which does not appear if the manganese is leeched out), other components of the cells showed very little staining in permanganate-fixed cells. Differences were noted between the reactivity of various polysaccharides. A strong generalized staining reaction was observed over sections of glutaraldehyde-fixed tissues, and this could be almost entirely blocked by pretreatment of the sections with iodoacetate; such treatment also indicated that there were comparatively few aldehyde groups present, either native and/or introduced by the fixative. Periodate oxidation then introduced staining groups in some Golgi bodies and cell walls, particularly in epidermal cells.