bluuebunny/crossref_metadata_2025 huggingface dataset:
RIBONUCLEASE AND DEOXYRIBONUCLEASE ACTIVITIES IN RAT AND MOUSE STRATIFIED SQUAMOUS EPITHELIA AND SKIN PAPILLOMAS
Authors: DAOUST R. , AMANO HARUKO
Published: April 2011

The distribution of ribonuclease and deoxyribonuclease activities was examined by substrate film methods in rat and mouse skin, mouth, tongue, and oesophagus epithelia and in skin papillomas.

In the various types of stratified squamous epithelia, nuclease activity was found to be localized in well-defined perinuclear zones in cells of the Malpighian layer. The activity in these sites increases from the lower to the upper layers and a strong band reaction corresponds to the limit between the non-keratinized and keratinized cell layers.

Apparently, the nucleases play an important role in the keratinization process in being responsible for the disappearance of nucleic acids which accompanies other radical changes taking place in transitional cells at the surface of the Malpighian layer.
LOCALIZATION OF DISACCHARIDASES IN EXTRACTS OF NEUROSPORA AFTER ELECTROPHORESIS IN POLYACRYLAMIDE GELS
Authors: EILERS F. I. , ALLEN J. , HILL E. P. , SUSSMAN A. S.
Published: April 2011

A technique for localizing the activity of disaccharidases on acrylamide gels is described. The technique is a modification of that of Dahlqvist and Brun and employs as the chromogenic reagent a mixture of glucose oxidase, nitro BT and phenazine methosulfate, with a disaccharide as the substrate. A formazan is deposited at the site of enzyme activity, thereby permitting localization. Through this means the invertase activity of several strains of Neurospora crassa has been investigated. Two of the "standard" strains used showed two invertases whereas a variant derived from one of these had only one. A trehalase which runs ahead of the invertases also has been demonstrated. A band is formed with cellobiose but is at the position of one of the invertases so that this enzyme may be of mixed specificity. No band was formed with lactose as substrate.
FACTORS AFFECTING THE STATE OF INJECTED HORSERADISH PEROXIDASE IN ANIMAL TISSUES AND PROCEDURES FOR THE STUDY OF PHAGOSOMES AND PHAGO-LYSOSOMES
Authors: STRAUS WERNER
Published: April 2011

It was attempted to find conditions at which the localization of injected horseradish peroxidase was preserved at its original sites and artifacts of diffusion and unspecific adsorption of peroxidase to nuclei and cell membranes were prevented. The main factors were thorough fixation of the tissue, osmotic protection with hypertonic sucrose, and avoidance of accumulation, in the fixation medium, of "free" peroxidase, diffusing out of the tissue. Artifacts of adsorbed peroxidase, produced intentionally in tissue of untreated rats by the addition of peroxidase to fixed tissue slices and sections, were compared with the localization in vivo of injected peroxidase in small and large phagosomes and on cell membranes. The uptake of peroxidase by cells of kidney slices in vitro was observed, in confirmation of similar observations by Holtzer and Holtzer (8) with fluorescein-labelled proteins. A procedure for the staining of injected peroxidase in fresh-frozen sections, and a procedure for the double staining of acid phosphatase and injected peroxidase in the same tissue sections, after formaldehyde fixation, was indicated.
EFFECT OF FREEZING AND THAWING ON CERTAIN NUCLEAR AND MITOCHONDRIAL ENZYMES OF MOUSE LIVER
Authors: WARAVDEKAR VAMAN S. , GOLDBLATT PETER J. , TRUMP BENJAMIN F. , GRIFFIN CHARLES C. , STOWELL ROBERT E.
Published: April 2011

1. The effects produced by a rapid freezing and thawing on the activities of some enzymes of nuclear (nicotinamide adenine dinucleotide (NAD)-pyrophosphorylase) and mitochondrial (succinoxidase, succinic dehydrogenase, and glutamic dehydrogenase) origin are presented. These effects are compared with those produced by sonic treatment of fresh tissue.

2. The activity of NAD-pyrophosphorylase was unaffected by the freezing procedures employed, namely dry ice at –79°C, isopentane at –155°C, and propane at –175°C, or by sonic treatment of homogenates of fresh tissue.

3. Succinoxidase activity was decreased to some extent by all the procedures employed. Sonic treatment produced a 47% loss in the enzyme activity, while freezing on dry ice, in isopentane, or in propane produced losses of 26, 29, and 37%, respectively.

4. The activity of succinic dehydrogenase was least affected by sonic treatment or by freezing on dry ice. Quenching in isopentane or in propane, however, produced 11% and 23% loss respectively in the dehydrogenase activity.

5. Free glutamic dehydrogenase activity, which is low in fresh-tissue preparations, was increased to the same extent by all methods employed. The unsedimentable activity depended upon the procedure used, however. Sonic treatment and freezing with propane, isopentane, or dry ice gave 78, 48, 33, and 20%, respectively, of the total enzyme activity.

6. The fact that the increase in unsedimentable glutamic dehydrogenase activity roughly parallels a decrease in succinoxidase activity suggests that a rapid freezing followed by thawing produces alterations in the mitochondrial membranes.
HISTOCHEICAL ALKYLATION: A STUDY OF METHYL IODIDE AND ITS EFFECT ON TISSUES
Authors: TERNER JACOB Y.
Published: April 2011

The use of methyl iodide as a histochemical alkylating agent is described. Methyl iodide selectively esterifies carbohydrate and other carboxyl groups. Sulfate half esters are not affected. Phosphate esters are esterified by methyl iodide, although the latter reaction is more variable; in several tissues nuclear basophilia could not be abolished. Saponification with barium hydroxide reverses the methyl iodide blockade of basophilia. Sulfhydryl and phenol reactions are prevented by methylation with methyl iodide; amines are alkylated and the usual blockade of acidophilia by acylation or deamination is prevented. Saponification does not reverse the blockade of these latter groups. The periodic acid-Schiff and Sakaguchi reactions are not affected. Marked increases in acidophilia were noted after methylation with methyl iodide. The hypothesis that a large number of tissue acids and amines are ordinarily prevented from binding basic and acid dyes respectively by intra- or intermolecular salt linkages is set forth. Similarly, the inability of protein end groups to demonstrate chemically determined pK values (to 2.5 for carboxyl groups and to 12.0 for arginine) in their interaction with dyes is attributed to interfering salt linkages.
A HISTOCHEMICAL METHOD FOR THE DEMONSTRATION OF 20α-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN RAT OVARIES
Authors: BALOGH KÁROLY
Published: April 2011

20α-Hydroxysteroid dehydrogenase activity was localized histochemically in the corpus luteum of the rat by using Nitro-BT as an indicator. Intensive enzyme activity was obseryed in the corpus luteum cells, especially during involution. The placenta and corpora lutea of pregnancy failed to reveal enzyme activity during the last week of gravidity. Other tissues, including endocrine glands, liver and kidneys were also negative. The Present method offers a possibility to identify the sites of progesterone metabolism in the rat ovary at the microscopic level.
HISTOCHEMICAL LOCALIZATION OF ENZYME ACTIVITY IN THE KIDNEYS OF THREE MAMMALIAN SPECIES DURING THEIR POSTNATAL DEVELOPMENT
Authors: WACHSTEIN MAX , BRADSHAW MAIRE
Published: April 2011

The activities of various enzymes were studied histochemically in two species which at birth have a kidney with an active nephrogenic zone, the rat and rabbit, and one (the guinea pig) in which this organ is at this time apparently fully matured. The histochemical reactions, in general, reflect the degree of maturity found in kidneys of newborn and growing animals. Immature proximal convoluted tubules lack enzymatic activity or show only minimal amounts. As these tubules mature, the adult pattern is noted at about the 14th to 16th day after birth in rat, and after 21 to 28 days in rabbit. Within this general pattern, however, considerable variations are noted. Glucose-6-phosphatase, e.g., is less active at birth, even in mature tubules, while acid phosphatase localized in granular "lysosomal" bodies is as prominent in newborn kidney as in adult. Newborn guinea pig kidney lacks glomerular adenosine triphosphatase activity in spite of its general enzymatic maturity, while rat kidney at birth has no tubular adenosine triphosphatase activity, even in more mature proximal convolutions.

Oxidative enzymes, particularly succinic dehydrogenase, and acid phosphatase are active in tubules of the inner portion of medulla in rat and rabbit at birth. This appears to be an expression of the immaturity of newborn kidney. With the progress of zonal differentiation, this enzyme activity is no longer found in the papillary portion of medulla where thin limbs of Henle's loop are now located. In rat kidney, best seen in cryostat sections briefly postfixed in very cold neutral formalin, single cells are found in the collecting ducts with striking 5-nucleotidase activity. The number of these cells is greater in neonatal kidney than in adult kidney. The physiological significance of many of the findings described in this report has still to be clarified.
LOCALIZATION OF UROMUCOID IN HUMAN KIDNEY AND IN SECTIONS OF HUMAN KIDNEY STONE WITH THE FLUORESCENT ANTIBODY TECHNIQUE
Authors: KEUTEL H. J.
Published: April 2011

Fluorescent labeled antibodies were used for the demonstration of uromucoid. This urine specific mucoprotein is demonstrably present only in the epithelial cells of the proximal segments of the normal human renal tubules and in the matrix of human kidney stones of all the common crystalline compositions.
SUCCINIC DEHYDROGENASE IN PIGEON PECTORALIS DURING DISUSE ATROPHY
Authors: CHERIAN K. M. , VALLYATHAN N. V. , GEORGE J. C.
Published: April 2011

Quantitative and histochemical changes in succinic dehydrogenase activity in pigeon breast muscle was studied during one to sixty days of disuse after immobilization of the wings. Muscle enzyme activity was found to decrease from the first day, reaching its lowest level after seven days. Histochemical observations on red and white muscle fibers showed that after seven days atrophy, the majority of red fibers had lower enzyme activity; a few others showed higher activity. In white fibers on the other hand, a uniform increase over normal in enzyme activity and mitochondrial number was seen. These changes in the two types of fibers were less conspicuous during the later stages of atrophy. Thus the general level of oxidative metabolism in muscle as a whole was lowered in spite of the slight increase in level of SDH in white fibers. It is suggested that in both red and white fibers there was a shift, of aerobic to anaerobic metabolism, or vice versa.
HISTOCHEMICAL DEMONSTRATION OF CATECHOLAMINE UPTAKE BY ADRENERGIC FIBERS
Authors: ANGELAKOS EVANGELOS T. , KING MARY
Published: April 2011

Uptake of catecholamines by adrenergic fibers was tested in isolated rat irises using the histochemical formaldehyde condensation technique. Minimum concentration in medium for detectable uptake was 0.5 µg/ml for the naturally-occurring catecholamines norepinephrine, epinephrine and dopamine. Adenosine mono-, di-, or triphosphate in minimum concentration of 0.01 µg/ml was required for amine uptake. Parallel specific chemical analyses confirmed the uptake of norepinephrine and epinephrine shown histochemically.
ALDEHYDE-FUCHSIN STAINING APPLIED TO FROZEN SECTIONS FOR DEMONSTRATING PITUITARY AND PANCREATIC BETA CELLS
Authors: JENNINGS BARBARA M.
Published: April 2011

Aldehyde-fuchsin staining was applied to fresh frozen sections to frozen sections pre-fixed with sucrose-formol, and to freeze-dried sections of human and animal pancreas and pituitary, with positive reactions in β-cells of both tissues. Successful adaptation of aldehyde-fuchsin staining to this material was achieved largely by choice of fixative, use of a fresh, nonchilled solution of aldehyde-fuchsin, and by acidified permanganate oxidation.

Certain standard fixatives (formol, Zenker-formol, and Bouin) proved satisfactory, as well as a more recently introduced one, glutaraldehyde. A fixation-staining technique requiring less than 10 minutes was evolved using stock (25%) glutaraldehyde.

With some of these fixatives, inserting an aldehyde blockade step when necessary, the Periodic and Schiff reaction could be employed as a control stain for aldehyde-fuchsin, with comparable results.

The methods adopted are useful in identifying β-cells in surgical specimens and in material used for enzyme reactions and fluorescent antibody techniques.
REVERSIBLE ACTIVATION OF LYSOSOMES IN RAT LIVER
Authors: GAHAN P. B.
Published: April 2011

Using the enzyme acid phosphatase as a marker for lysosomes, a histochemical study has been made of the effects of the operative procedure for partial hepatectomy upon the lysosomes of rat liver. The procedure was considered in three stages: i) ether anaesthesia; ii) laparotomy; iii) laparotomy and handling of the left and ventral lobes. With increasing severity of procedure shorter times of incubation in test medium were required to demonstrate lysosomes in liver. This was considered to indicate an increased permeability of lysosomal membrane to the substrate, β-glycerophosphate. Response was not immediate, but increased to a maximum with time, finally returning to normal. The reversible change in lysosomes was considered to reflect a physiological response by these particles to cell damage.
MICROSCOPIC IMMUNOFLUORESCENCE OF GLOMERULI IN CHRONIC NEPHROTOXIC SERUM NEPHRITIS
Authors: BOSS J. H.
Published: April 2011

The microscopic immunofluorescence of the glomeruli differs in acute and chronic nephrotoxic serum nephritis in the distribution pattern of the injected nephrotoxic globulin and the host's gamma globulin. In acute nephritis specific glomerular fluorescence, denoting fixation of nephrotoxic and recipient's gamma globulin, is sharply limited to regular, thin and delicate lines corresponding to the capillary basement membranes. On the other hand, specific glomerular fluorescence in chronic nephritis appears as irregular, broad and tortuous loops consisting of coarse, partially coalescing specks of differing brightness. This difference is possibly related to the profound alterations in chronic nephritis resulting in reconstruction of the glomerular architecture.
SMALL TISSUE DRYERS WITH HIGH CAPACITY FOR RAPID FREEZE-DRYING
Authors: THIEME GEORGE
Published: April 2011

In close connection to the development of a new histochemical technique the need for a small high capacity freeze dryer greatly increased. A convenient system was devised, which allows work with several independent drying chambers simultaneously. The cooling source is a standard refrigeration plant equipped with an expansion coil in a Dewar flask from which cold liquid is distributed to the separate drying units. The specimen carrier of each unit can take about twenty tissue pieces. Even though diffusion pump, cold finger trap, and other delicate components have been avoided, drying time is quite favourable; it may be as little as five hours for pieces of standard size. Moreover, the evacuation pump is well protected against vapor. The freeze dryer is built mainly of standard components or inexpensive modifications of these.
AUTORADIOGRAPHY OF DIFFUSIBLE IONS WITH APPLICATION TO THYROIDAL RADIOIODIDE
Authors: ANDROS GEORGE , WOLLMAN SEYMOUR H.
Published: April 2011

A method for the autoradiographic localization of water-soluble diffusible ions has been developed and applied to the localization of iodide125 in the mouse thyroid gland. Frozen-dried thyroids of hypophysectomized mice containing radioiodine125 as inorganic iodide125 were embedded in paraffin. Sections were spread on mercury and mounted on autoradiographic film. After exposure the mounted section was permanently fastened directly over its latent image and tissue constituents were fixed by dipping in 80% aqueous methanol. The preparation was air dried and then deparaffinized with petroleum either. After development and fixation, slides were stained with Nuclear Fast Red. In certain cases radioiodide could be localized primarily in the follicular epithelium. Control studies demonstrated that the autoradiographic image was not an artifact resulting from chemical induction or suppression of selected areas of latent image. A comparison of autoradiographs prepared from frozen sections and those prepared by freeze-drying showed similar localization of the radioisotope and indicated that there was no displacement of the radioiodide during paraffin embedding.
THE PERIODATE-SCHIFF REACTION: SPECIFICITY, KINETICS, AND REACTION PRODUCTS WITH PURE SUBSTRATES
Authors: DAHLQVIST ARNE , OLSSON INGE , NORDÉN ÅKE
Published: April 2011

A quantitative test-tube method has been used to study the periodate-Schiff reaction of a number of pure substances. The rate of reaction, the amount of color produced, and in some cases the amount of periodate consumed, have been measured. The dye produced by different carbohydrates has been analyzed by spectrophotometry and paper chromatography. Glycogen, starch and dextran reacted slowly and produced much less color than the corresponding amount of free monosaccharides. Oligosaccharides and heteropolysaccharides were either periodate-Schiff-negative or very weakly positive. Proteins and nucleic acids were negative. There was no simple relation between the intensity of the periodate-Schiff reaction and the amount of periodate consumed or the amount of aldehyde groups formed on the oxidation by periodate. The dyes formed with different carbohydrates had essentially the same absorption curve, but differed in their chromatographic mobility.
THE HISTOCHEMICAL DEMONSTRATION OF URICASE ACTIVITY
Authors: GRAHAM RICHARD C. , KARNOVSKY MORRIS J.
Published: April 2011

The histochemical demonstration of uricase activity in rat and guinea pig liver is described. The technique depends upon the generation of H2O2 during the uricase reaction. The liberated H2O2 participates in a coupled peroxidatic oxidation of 3-amino-9-ethylcarbazole, resulting in the deposition of an insoluble red oxidation product at the sites of uricase activity. This activity appeared as small, discrete red granules througout the cytoplasm of hepatic parenchymal cells of the rat and guinea pig. The distribution was clearly different from that of acid phosphatase activity in similar sections, which appeared typically pericanalicular. These results are consistent with other data indicating that uricase is associated with microbodies in the rat liver, and that microbodies and lysosomes are separate entities.
LOCALIZATION OF SKELETAL MUSCLE PHOSPHORYLASE USING A FLUORESCENT ANTIBODY TECHNIQUE AND ITS CORRELATION WITH HISTOCHEMICAL OBSERVATIONS
Authors: DVORAK HAROLD F. , COHEN RICHARD B.
Published: April 2011

The Coons fluorescent antibody technique was employed to localize rabbit muscle phosphorylase within striated muscle cells. Pooled sera from guinea pigs sensitized against 2X crystallized rabbit phosphorylase a in complete Freund's adjuvant gave a single line of precipitation with the enzyme in Ouchterlony plates. Such sera, tagged with fluorescein isothiocyanate and applied to thin frozen sections of rabbit striated muscle, produced a specific, granular, fluorescing precipitate which was localized to the sarcoplasm between myofibrils. Preincubation with untagged specific antisera prevented specific staining. Appropriate control sera, similarly tagged, produced only slight nonspecific fluorescence. With properly absorbed specific antisera, staining was specific for striated muscle as opposed to rabbit liver or smooth muscle. The fluorescent antibody findings were correlated with those obtained by classical histochemieal studies of phosphorylase activity. In addition, application of antisera to sections of rabbit muscle before incubation in substrate resulted in significant inhibition of histochemically demonstrable phosphorylase activity whereas control sera had little or no inhibitory effect.
FLUORESCENCE METHODS FOR THE HISTOCHEMICAL DEMONSTRATION OF MONOAMINES: 4. HISTOCHEMICAL DIFFERENTIATION BETWEEN DOPAMINE AND NORADRENALINE IN MODELS
Authors: CORRODI HANS , JONSSON GÖSTA
Published: April 2011

If primary catecholamines e.g. dopamine and noradrenaline in a dried protein layer are exposed to gaseous formaldehyde, they are converted to intensely fluorescent 6,7-dihydroxy-3,4-dihydroisoquinolines. This reaction can be used for the histochemical demonstration of these amines.

The fluorescent products of dopamine and noradrenaline have practically identidal activation and emission spectra. The 4,6,7-trihydroxy-3,4-dihydroisoquinoline formed from noradrenaline has, however, a labile hydroxy group at 4-position which can be easily split off. This dehydration to the fully aromatic 6,7-dihydroxyisoquinoline was found to take place readily in a dried protein layer by treatment with thionyl chloride gas at 50°C. The isoquinoline shows other flurorescence characteristics than the 3,4-dihydroisoquinolines and is not reduced by sodium borohydride. A direct histochemical differentiation between dopamine and noradrenaline is thus possible.
HISTOCHEMICAL STUDY OF LIPIDS IN HUMAN SEBACEOUS GLANDS
Authors: NASR AHMED N.
Published: April 2011

Different classes of lipids human sebaceous glands were identified and localized using histochemical methods. Sebaceous glands contain phospholipids associated with the membranes of the mitochondria and the Golgi elements. The structure of the Golgi elements in sebaceous cells at different levels of differentiation shows a close relationship to what was related by the electron microscope. This supports the phenomenon that the Golgi region is the center of sebum formation. The sebaceous acinar cells do not contain any appreciable amount of sterols whereas sebum abounds in cholesterol esters which may come from keratinizing cells of sebaceous duct and philosebaceous canal and from disintegrating cells of the inner root sheath. Nile blue staining reveals that the newly formed sebum within the sebaceous cells is mainly composed of glycerides while old sebum contains both glycerides and free fatty acids. Surface lipids resemble sebum in composition, but they contain free cholesterol white sebum does not. This free cholesterol may originate from cholesterol esters through the action of nonspecific esterases.
COMPARISON OF FIXATIVES AND SUBSTRATES FOR AMINOPEPTIDASE
Authors: MONIS BENITO , WASSERKRUG HANNAH , SELIGMAN ARNOLD M.
Published: April 2011

Although aminopeptidase activity is extensively inhibited by glutaraldehyde, it is sufficiently well preserved after brief glutaraldehyde fixation for histochemical use in active tissues in contrast to the too great losses with comparable formaldehyde-fixation. The localization of histochemical activity is sharper with glutaraldehyde-fixed frozen sections than with fresh frozen sections in many tissues though not all, and both methods are better than with formalin fixed tissue. Comparison of the results with leucyl, methionyl and alanyl amides of the rapid coupler, 4-methoxy-2-naphthylamine, showed exactly the same localization.
DIFFERENTIAL STAINING OF ULTRATHN SECTIONS OF EPON-EMBEDDED TISSUES FOR LIGHT MICROSCOPY
Authors: LANE BERNARD P. , EUROPA DOMINIC L.
Published: April 2011

A convenient method is described for the removal of Epon 812 from thin sections, utilizing a saturated solutions of sodium hydroxide. The tissue architecture and ultrastructural details are preserved. Hematoxylin-eosin, periodic acid-Schiff and phosphotungstic-hematoxylin staining modifications are suggested which result in differentiation similar to that seen in paraffin sections. The technique is applicable to ultrathin sections suitable for examination with the electron microscope, allowing comparison of staining characteristics and fine structure of adjacent thin sections.
LOCALIZATION OF MITOCHONDRIAL ADENOSINE TRIPHOSPHATASE ACTIVITY IN CULTURED HUMAN CELLS
Authors: ESSNER EDWARD , FOGH JØRGEN , FABRIZIO PATRICIA
Published: April 2011

Adenosine triphosphatase activity has been localized by light microscopy in the mitochondria of four different types of cultured cells using the Wachstein-Meisel lead method after brief fixation in formol-calcium. The resolutions of the method permits the study of mitochondrial size, form, number and distributions in these cultured cells. Electron microscopy shows enzyme reaction product within the mitochondrion but not on the outer mitochondrial membrane. Reaction product is also localized to the plasma membrane and its infoldings.
THE LOCALIZATION OF SUCCINIC DEHYDROGENASE, CYTOCHROME OXIDASE AND ADENOSINE TRIPHOSPHATASE IN CILIATED RESPIRATORY EPITHELIUM
Authors: CRESS HERTHA R. , SPOCK ALEXANDER , HEATHERINGTON DUNCAN C.
Published: April 2011

Succinic dehydrogenase and cytochrome oxidase activities were found to be scattered throughout the cytoplasm of ciliated and nonciliated respiratory epithelial cells while ATPase activity was restricted to cilia and areas under the cilia in the regions of the ciliary basal bodies. In order to elucidate the role of ATPase further, tissue cultures of rabbit tracheal epithelium with beating cilia were incubated in a medium perfused with cigarette smoke which resulted in cessation of ciliary motility. Epithelium with beating cilia was positive for ATPase while the epithelium with nonbeating cilia was negative or only weakly positive in a few small scattered areas. The presence of ATPase in beating cilia and its absence in nonbeating cilia agree with biochemical and physiological studies suggesting an association between ATP and ciliary activity.
Opening Pandora’s box: The unintended consequences of Stephen Covey’s effectiveness movement
Authors: McCabe Darren
Published: April 2011

A number of critics have analysed management guru ‘texts’ and their analysis suggests that we have much to fear from them. This article, by contrast, explores a customer service intervention in a UK bank that drew on ‘some’ of the ideas of the management guru, Stephen Covey. The article highlights that guru texts do not translate from the page to practice in an unproblematic way. This is because they must be interpreted and are filtered through existing social contexts. Second, the ideas are often flawed and third, they meet with resistance. The central argument is that management gurus are less powerful than many critics assume because neither gurus nor managers are able to control how their ideas are consumed.
Innovations in a relational context: Mechanisms to connect learning processes of absorptive capacity
Authors: Knoppen Desirée , Sáenz Maria J , Johnston David A
Published: April 2011

Companies increasingly regard relationships with other companies as a source of competitive advantage. Relationships constitute a context in which the firm may learn and build absorptive capacity. This study provides an in-depth explanation of the key mechanisms that interlace the different learning processes leading to innovations in a relational context. A theoretical elaboration of these mechanisms precedes their empirical study within four customer-supplier dyads, centred on two focal customer organizations.The article contributes by discussing how the mechanisms act and interact to create absorptive capacity for a focal firm across relationships. We find that structural learning mechanisms, while necessary are not sufficient to explain variation in the presence of absorptive capacity across different learning contexts. Cultural, psychological and policy learning mechanisms complement the picture. From the empirical analysis we derive propositions to guide further research into the creation of absorptive capacity in a relational context.
Knowledge sharing through virtual teams across borders and boundaries
Authors: Kauppila Olli-Pekka , Rajala Risto , Jyrämä Annukka
Published: April 2011

This study focuses on a challenge faced by multinational corporations: how to enhance knowledge sharing across geographical and functional boundaries given the multifaceted nature of knowledge. The article demonstrates how a multinational company can create the means and spaces necessary to achieve effective knowledge sharing and learning by highlighting a viable information system that supports social networking. It also offers a virtual team structure that draws upon and strengthens employees’ social ties, which can boost organization-wide management of fine-grained knowledge. This combined approach mitigates the negative effects of physical and organizational distance on the availability of support and information. The present study contributes to organizational learning and knowledge-sharing discussions by shedding light on how virtual teams that function as knowledge activists can enhance internal knowledge sharing in globally dispersed organizations.
The spatial psychodynamics of management learning
Authors: Vince Russ
Published: April 2011

This article addresses the question: how can we help managers to understand the emotional and political dynamics that surround and permeate their managerial roles? A conceptual framework is presented that is based on the integration of literature on space with literature that has taken a psychodynamic approach to management learning. The term spatial psychodynamics describes the way in which juxtapositions of material, relative and relational space in the management classroom can reveal dynamics that help managers to perceive the emotions and politics that are part of their roles. Three characteristics of spatial psychodynamics are presented: unconscious dynamics and the interpretation of learning space, the political effects of fantasy in learning space, and how juxtapositions of space create distinctiveness of place. An example is discussed in order to illustrate how this concept can improve our ability to engage with emotional and political dynamics in the management classroom.
That’s why it matters: How knowing creates value
Authors: Swart Juani
Published: April 2011

This article develops our understanding of how knowing creates value.It contributes to the interactionist perspectives on knowledge in three particular ways: first, it recognizes that knowledge is only valuable when it is enacted, i.e. know-how-in-action (KHiA). Second, it develops a typology of value creating options, i.e. clones, talent rich, resource rich and synergists, which represent multiple options that we can enact. These value creating types are sensitive to the socio-systemic and personal nature of knowing. Finally, it addresses the power dynamics within each value creating option. This lens re-introduces the individual power dynamics which impact on future value-creating processes.
Provocative theory and a scholarship of practice
Authors: Ramsey Caroline
Published: April 2011

The relationship between theory and management practice is an ongoing debate. This article identifies two current understandings of that relationship—explanation and sense making—and offers a third, ‘provocative’ use of theory. Drawing on social constructionist ideas, a provocative theory is articulated as a relational process whereby academic theory ‘speaks into’ management practice. Having outlined the intellectual roots of provocative theory, two illustrative case studies are used to show how a provocative theory worked as managers engaged academic scholarship within a practice of inquiry to improve their managerial practice. These two stories illustrate a scholarly engagement with academic theory, as the two managers exhibited an engagement with ideas, a practice of inquiry and an attention to moment-by-moment relating within practice. These three processes are argued to constitute a scholarship of practice, where scholarship is seen in amidst moment-by-moment activity of evidence-based management.
Validity of DSM-IV syndromes in preschoolers with autism spectrum disorders
Authors: Lecavalier Luc , Gadow Kenneth D. , Devincent Carla J. , Houts Carrie R. , Edwards Michael C.
Published: April 2011

Behavior and emotional problems are often present in very young children with autism spectrum disorders (ASDs) but their nosology has been the object of scant empirical attention. The objective of this study was to assess the construct validity of select Diagnostic and Statistical Manual of Mental Disorders (DSM)—defined syndromes (ADHD, ODD, Mood disorder) in preschoolers with ASD ( N = 229). Parents and teachers completed the Early Childhood Inventory—4, a behavior rating scale based on the DSM-IV, and ratings were submitted to confirmatory factor analysis. Results generally supported the DSM nosology in this population. There was some evidence that parent ratings were associated with better fit indices (e.g. RSMEA = .062) than teachers (e.g. RMSEA = .083). For both raters, fit indices appeared to improve when the ADHD factor was broken into its constituent parts. However, hyperactivity symptoms accounted for little unique additional variance in the model. Findings lend support to the DSM as a conceptual model for behavioral syndromes in preschoolers with ASDs and also reinforce the importance of source-specificity when considering psychiatric disorders in children with ASDs.
The progress of inclusive education in South Africa: Teachers’ experiences in a selected district, KwaZulu-Natal
Authors: Ntombela Sithabile
Published: April 2011

Education policies tend to evoke mixed feelings: excitement amongst advocates of change or uncertainty and stress among teachers expected to implement them. Reactions to the Education White Paper 6: Special Needs Education — Building an Inclusive Education and Training System have been no different. Emanating from a PhD study, this article documents how inclusive education is progressing in the province of KwaZulu-Natal. Informed by social constructivism and the systems theory, the study investigated teachers’ experiences and understandings of this policy statement in three primary schools in two districts. Data collected showed that teachers had limited experiences of inclusive education and limited understandings of what it entails in South Africa. As a result, most teachers felt inadequately prepared to implement it. The article concludes that the limited experiences and understandings result from, among other things, the inadequate and inappropriate professional development strategy used to disseminate information within the Department of Education.
Exploring professional knowledge-building through an inter-school visits programme
Authors: Roberts Amanda
Published: April 2011

This article explores the learning arising from a pilot inter-school visits programme in Stevenage, Hertfordshire. Teachers from two schools undertook a series of visits with the aim of developing learning and teaching in their schools. The pilot sought to understand ways in which such a collaborative visits programme could be used to build professional knowledge across school boundaries. It suggests that such knowledge-building is the precursor to a change of practice. An investigation of the literature reveals potential issues in making tacit knowledge visible and in recording teachers’ learning so that it can contribute to a developing professional knowledge base. The article discusses how these issues manifested themselves in practice and offers a framework for professional learning visits which underlines the continuous nature of professional learning, the need for reflection to decode what has been learned and the need for active and continuing participation by host and visitor in order to effect a change in practice. It concludes by considering the challenges of a full visits programme and how such a programme may be used to strengthen teachers’ capacity for innovation.
THE DETERMINATION BY QUANTITATIVE HISTOCHEMISTRY OF THE EFFECT OF PHENOTHIAZINES ON BRAIN CYTOCHROME C OXIDASE ACTIVITY
Authors: MORACZEWSKI ALBERT , ANDERSON RAE C.
Published: April 2011

The Burstone method (1961) for the histochemical demonstration of cytochrome c oxidase was quantified and applied to the study of the effects of chlorpromazine and trifluoperazine on the activity of this enzyme in rat forebrain, hypothalamus, cerebellum and pons-medulla. Fresh frozen, 10-µ-thick sections from rat brain were incubated in a buffered medium containing p-aminodiphenylamine and 8-amino-1,2,3,4-tetrahydroquinoline. The colored oxidized product of cytochrome c oxidase activity was extracted with ethanol and the optical density determined. In one series of experiments the phenothiazine was added to the incubating medium. For 50% inhibition of cytochrome c oxidase the following average tissue concentrations of chlorpromazine were required: cerebellum, 20 mM; forebrain, 27 mM; pons-medulla, 42 mM. Trifluoperazine was required in higher concentrations: cerebellum, 38 mM; forebrain, 47 mM; ponsmedulla, greater than 70 mM. In another series the phenothiazine was given intraperitoneally, 100-200 mg/kg. No significant inhibition of the enzyme was noted. The tissue concentration in vivo of the drug was well below the tissue concentration in vitro associated with minimum enzyme inhibitions.
HISTOCHEMICAL DEMONSTRATION OF 3α-HYDROXYSTEROID DEHYDROGENASE ACTIVITY
Authors: BALOGH KÁROLY
Published: April 2011

The reversible oxidation of 3α-hydroxysteroids to their corresponding 3-keto forms comprises an important step in the metabolism of C19-steroids. The described techniquue demonstrates the activity of the enzyme catalyzing this reaction, with the use of androsterone as a substrate and a tetrazolium salt as the final electron acceptor. The enzyme is specific for 3α-hydroxysteroids; there was no histochemical reaction with epiandrosterone, the β isomer of androsterone. Since 3α-hydroxysteroid dehydrogenase is soluble in aqueous solutions, it was necessary to increase the osmolarity of the incubation medium by adding polyvinylpyrrolidone in a final concentration of 20%. Although the enzyme has a dual nucleotide specificity, no appreciable differences were seen in its distribution pattern in rat tissues with either NAD or NADP as a coenzyme. In adult female rats, enzyme activity was present in the liver, kidneys and clitoral glands. In mature males, diformazan deposits were observed in the liver, kidneys, preputiai glands, epididymis, ventral prostate and Leydig cells.
SELECTIVE LOCALIZATION OF NUCLEOLAR PROTEIN WITH AMIDO BLACK 10B
Authors: MUNDKUR B. , BRAUER B.
Published: April 2011

Interphase nucleoli of Ehrlich ascites tumor cells were stained with amido black 10B to the exclusion of all other regions of interphase and mitotic cells. Proteins of the ascites fluid also remained unstained. Selectivity of the dye for nucleolar protein, established by blocking and extraction methods, is metal-mediated and involves amino groups predominantly. The conditions leading to selectivity are narrowly circumscribed in Ehrlich ascites tumor cells and, thus far, have not yielded equally satisfactory results with nontumor material to warrant general applicability of the method. A tentative explanation of the phenomenon is offered on the basis of numerous control experiments involving freezing-drying, variations in composition and application of reagents and other pertinent cytochemical procedures. The findings suggest that nucleolar proteins possess certain unique properties which are lost on altered to the extent that they are insensitive to the amido black 10B method once the proteins are released from the interphase nucleolus.
LEAD ION AND PHOSPHATASE HISTOCHEMISTRY II. EFFECT OF ADENOSINE TRIPHOSPHATE HYDROLYSIS BY LEAD ION ON THE HISTOCHEMICAL LOCALIZATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY
Authors: MOSES HAROLD L. , ROSENTHAL ALAN S. , BEAVER DAVID L. , SCHUFFMAN SHIRLEY S.
Published: April 2011

The lead method of Wachstein and Meisel for the histochemical localization of adenosine triphosphatase (ATPase) involves the incubation of sections of fixed tissue in reaction mixtures containing ATP, lead nitrate, magnesium sulfate and a Tris-maleate buffer, pH 7.2. Both fixation and the presence of lead ion were shown to inhibit tissue ATPase activity markedly and to inactivate the sodium- plus potassium-dependent membrane ATPase. In addition, recent studies have demonstrated that lead ion, in the concentration used in the Wachstein-Meisel system, will catalyze the hydrolysis of ATP. Studies on the effect of this nonenzymatic reaction on the histochemical localization of ATPases demonstrated that plasma membrane localization occurred only with lead and ATP concentrations which gave significant nonenzymatic hydrolysis of ATP by lead. In addition, nuclear and mitochondrial localization without accompanying plasma membrane localization could be obtained in formalin-fixed tissue with decreased concentrations of lead or with increased concentrations of ATP in the reaction mixture. The amount of lead-catalyzed hydrolysis was in the same order of magnitude as fixed tissue ATPase activity and could quantitatively account for the amount of phosphate needed to give recognizable localization of lead salt deposits in sections of fixed tissue.
METHOD FOR ENHANCEMENT OF ELECTRON MICROSCOPIC VISUALIZATION OF EMBEDDED ANTIGEN BY BRIDGING OSMIUM TO URANIUM ANTIBODY WITH THIOCARBOHYDRAZIDE
Authors: STERNBERGER LUDWIG A. , HANKER JACOB S. , DONATI EDWARD J. , PETRALI JOHN P. , SELIGMAN ARNOLD M.
Published: April 2011

Thiocarbohydrazide (TCH), a bidentate ligand, capable of bridging osmium to osmium in ultrathin sections (OTO method), was shown to possess the additional property of binding osmium to uranium-labeled antibody. On sections in which acrolein-fixed antigen had been localized for electron microscopy by uranium antibody, application of TCH followed by osmication (T-O procedure) greatly enhanced the specific contrast afforded. In addition, the T-O procedure yielded better resolution and better stability to the electron beam than the immunouranium technique employed without this intensification. Even osmium tetroxide-fixed tissue could be used, providing thiosemicarbazide (TSC) was employed to block the later reaction of TCH with tissue-bound osmium and to limit, thereby, the ligation of TCH to the uranium-labeled antibody.
AN ELECTRON MICROSCOPY STUDY OF PHOSPHATASE ACTIVITY IN THE ENDOTHELIAL CELLS OF RABBIT AORTA
Authors: HOFF HENRY F. , GRAF JÜRG
Published: April 2011

The fine structural localization of phosphatase activity in the endothelial lining of rabbit aorta was studied using the electron microscope. The tissue was incubated in media containing various substrates at different pH values. Only a neutral phosphatase activity was localized with a preferential specificity for adenosine triphosphate (ATP), although some affinity was found with adenosine diphosphate, adenosine monophosphate, β-glycerophosphate and phenylphosphate. The reaction product (lead phosphate), with ATP and ADP as substrates, was localized primarily in cell membrane invaginations at the intercellular spaces and in neighboring pinocytotic vesicles, and only slightly in similar invaginations at the luminal and intimal surfaces. Enzyme localization was similar using the other substrates, but with a lower concentration of reaction product that was absent from the invaginations at the luminal surface. The significance of these observations in light of the role of cytopempsis in intimal nutrition and pathogenesis of atherosclerosis is briefly discussed.
INFRARED SPECTROPHOTOMETRY ITS USE IN CHARACTERIZING HISTOCHEMICAL REACTION MECHANISMS
Authors: KVISTBERG DAVID R.
Published: April 2011

The technique of infrared analysis can be applied to histochemical and cytochemical problems. The approach outlined here illustrates the application to the mechanism of staining, starting with model compounds and tissue components.

Future use of an infrared microscope employing improvements of modern electronics and optics should enable direct correlation of model studies with in situ studies.
HISTOCHEMICAL DEMONSTRATION OF PHOSPHOLIPASE B (LYSOLECITHINASE) ACTIVITY IN RAT TISSUES
Authors: OTTOLENGHI ATHOS , PICKETT JOHN P. , GREENE WILLIAM B.
Published: April 2011

A method has been developed for the histochemical demonstration of phospholipase B (lysolecithinase) of rat tissues. The enzyme attacks lysolecithin with liberation of 1 mole of glycerylphosphorylcholine and 1 mole of fatty acid. The recommended procedure involves use of 6-10 µ frozen sections, fixed in cold calcium-formol and incubated at 37°C in Tris buffered medium at pH 6.6 containing 2.2 x 10–3 M lysolecithin and 1% cobalt acetate. The fatty acid liberated by enzymatic hydrolysis is trapped as a cobalt precipitate and is then converted to a blackbrown precipitate by treatment with dilute ammonium sulfide in cold isotonic saline. Equivalent amounts of fatty acid and glycerylphosphorylcholine are recovered by extraction and analysis of the incubated sections and of the incubation medium, thus proving that lysolecithin hydrolysis occurs under the proposed reaction conditions. Staining is reduced by treating the sections with copper ions, mercury compounds, alcohols, acetone and by heating at 60°C prior to incubation with substrate. Lowering of the pH of the incubation medium has similar effect. These findings are interpreted as evidence of the enzymatic nature of the reaction. Cells exhibiting a positive staining are found in the lamina propria of the intestinal villi and crypts, in the red pulp of the spleen and in the interstitial tissue of lung, liver and thymus. Similar elements are present in bone marrow smears and in leukocyte preparations obtained by peritoneal lavage. The morphologic and staining characteristics of these cells correspond to those of the eosinophilic leukocytes. Physical and chemical agents (x-irradiation corticosteroids) which sharply decrease the number of eosinophils also reduce the number of cells shown histochemically to hydrolyze lysolecithin. A correspondent. diminution of phospholipase B activity of homogenates of the same tissues can be shown in vitro. Differences in tissue distribution and chemical properties distinguish the phospholipase B from less specific esterases and lipases.
RELATIONSHIP BETWEEN GLYCOGEN AND AGRANULAR ENDOPLASMIC RETICULUM IN RAT HEPATIC CELLS
Authors: DE MAN J. C. H. , BLOK A. P. R. , BEENS W.
Published: April 2011

The relation between agranular reticulum and glycogen was studied in hepatic cells of female rats. Prolonged fasting of nonadrenalectomized rats did hot result ins complete liver glycogen depletion, whereas in adrenalectomized rats this could be accomplished within a few hours of fasting. In nonadrenalectomized rats a marked development of agranular reticulum associated with glycogen was found, whereas in adrenalectomized rats no such marked development of agranular reticulum was seen during glycogen depletion. Early glycogen restoration in glycogen-depleted liver cells of adrenalectomized rats was brought about 2-4 hr after the injection of 1 dose of cortisone or ½-1 hr after the injection of glucose. Early restoration of glycogen was accompanied and even preceded by a marked development of tubular agranular reticulum. A probable role of this organelle in glycogen synthesis and breakdown is discussed. High resolution autoradiography of tritium-labeled glucose incorporation offered some further illustration on the process of glycogen formation.