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PubMed1981

Immunofluorescent localization of two water-soluble glycoproteins including the major allergen from the pollen of ryegrass, Lolium perenne.

Two major glycoproteins have been localized in sectioned grains of ryegrass pollen by direct and indirect immunofluorescence methods using Fluorescein isothiocyanate (FITC)-labelled IgG fractions of antisera. These glycoproteins are the major allergen, Group 1 allergen, and a principal antigen, Antigen A. Four methods of fixation were employed: freeze-drying, methanol, 2.5% glutaraldehyde and 4% paraformaldehyde for 1 h at 4 degrees C. The post-embedding staining technique of immunocytochemistry was used: anthers were embedded directly, or after dehydration, in JB-4 plastic resin and antibody reacted with sectioned pollen. The effects of these fixatives on the antibody combining sites of the antigens were quantified by a solid phase radioimmunoassay using [125I]protein A to measure antibody binding. In mature pollen, these antigens were located in the cytoplasm and in the complex wall. In developing grains early in the maturation period, specific fluorescence was concentrated at the periphery of the cytoplasm.

Allergens↗

PubMed1983

A simple post-embedding system for the rapid demonstration of tissue antigens under the electron microscope.

A simple and versatile technique for the preparation of ultra-thin sections, which can be stained immunohistochemically directly on electron microscope grids, is presented. An anti-hapten immunoperoxidase procedure has been adapted for use on tissue fixed in a purified monomeric glutaraldehyde--picric acid mixture, and embedded in 'L R White', a recently formulated plastic resin. This plastic tolerates the use of partial dehydration of tissue, resulting in higher antigenic yields. In addition, no etching of ultra-thin sections is necessary, and the whole immunostaining procedure can be completed in less than 2 h. A comparison of commonly used fixatives is discussed. High-resolution micrographs showing general staining (uranyl acetate--lead citrate) of rat pancreas, and immunostaining of insulin and TSH in storage granules in perfusion-fixed rat tissue and of lambda-chain immunoreactive cells in immersion-fixed human tonsil are included as examples.

Animals↗

PubMed2004

Sex differences in common Marmosets (Callithrix jacchus) in response to an unfamiliar food task.

There is a growing body of information on sex differences in callitrichid behaviour that includes the animals' performance in food tasks. For example, both reproductive and non-reproductive adult females have been found to be more successful than adult males in solving food tasks. In this study ten adult male and ten adult female common marmosets (Callithrix jacchus), housed individually, were tested with an unfamiliar task that involved the extraction of an embedded food. The task was to open a plastic canister that contained a raisin; the open end was covered with parchment paper. Each marmoset was given 15 trials in three blocks of 5 consecutive days. We measured the latency for each animal to open the lid and get the raisin--by one of five strategies that spontaneously emerged. The females learned the task faster and more efficiently than males; all the females opened the canister on day 1, for instance, in contrast to seven of the males on the same day. Females also progressively decreased the time that they took to open the tube. The final latency on day 15, for instance, was significantly shorter for the females. These results are consistent with relevant literature for callitrichids and cannot be accounted for in terms of differences in mental abilities, strength, hand morphology, or energy requirements. Further investigation is necessary to clarify the reasons for these differences.

Animals↗

PubMed1980

Generation of monodisperse fibrous glass aerosols.

Investigations of the aerodynamic behavior of fibers, lung deposition studies which involve fibers and investigations which are concerned with the biological effects of fibers create the need for fibrous aerosols monodisperse with respect to both fiber length and diameter. The method of preparation presented in this paper is primarily based on embedding the bulk quantity of fibers in a plastic histological preparation medium and subsequently cutting the fibers to the desired lengths. The slices which are obtained by the microtoming process are purified of the plastic medium by burning and ashing and the fibrous dust obtained in this manner is then cleared of any debris by liquid elutriation. The results show that gram quantities of nearly monodisperse glass fiber dust with lengths of up to 50 micrometers can be obtained.

Aerosols↗

PubMed2005

Detached leaf assay to screen for host plant resistance to Helicoverpa armigera.

The noctuid Helicoverpa armigera (Hübner) is a major insect pest of chickpea Cicer arietinum L., pigeonpea Cajanus cajan (L.) Millsp., peanut Arachis hypogaea L., and cotton Gossypium spp., and host plant resistance is an important component for managing this pest in different crops. Because of variations in insect density and staggered flowering of the test material, it is difficult to identify cultivars with stable resistance to H. armigera across seasons and locations. To overcome these problems, we standardized the detached leaf assay to screen for resistance to this pest in chickpea, pigeonpea, peanut, and cotton under uniform insect pressure under laboratory conditions. Terminal branch (three to four fully expanded leaves) of chickpea, first fully expanded leaf of cotton, trifoliate of pigeonpea, or quadrifoliate of peanut, embedded in 3% agar-agar in a plastic cup/jar of appropriate size (250-500-ml capacity) infested with 10-20 neonate larvae can be used to screen for resistance to H. armigera. This technique keeps the leaves in a turgid condition for approximately 1 wk. The experiments can be terminated when the larvae have caused > 80% leaf damage in the susceptible check or when differences in leaf feeding between the resistant and susceptible checks are maximum. Detached leaf assay can be used as a rapid screening technique to evaluate germplasm, segregating breeding materials, and mapping populations for resistance to H. armigera in a short span of time with minimal cost, and under uniform insect infestation. It also provides useful information on antibiosis component of resistance to the target insect pest.

Animals↗

PubMed1989

Electrode for selective recording of electromyograms from intercostal muscles.

An electromyogram-recording electrode is described that makes it possible to record separately the electrical signals generated within two closely approximated muscle layers. The device consists of two bipolar wire hook electrodes embedded in opposite faces of a thin laminated plastic wafer. The middle lamina of the wafer is a sheet of metal foil that shields the electrical field on one side of the wafer from the bipolar electrode on the other side. The device was tested by inserting it from the inside of the chest wall between the internal and external intercostal muscle layers. Signals from the two muscle layers were clearly separated. Single motor unit spikes were attenuated by factors ranging from 41 to 2.4. The device can be implanted with minimal trauma to surrounding muscles and is suitable for chronic animal experiments.

Animals↗

PubMed1987

Serial sectioning techniques for a modified LKB Historesin.

A glycol methacrylate-based plastic that is capable of producing serial sections has been introduced by LKB. This plastic, provided in the LKB 2218-500 Historesin Embedding Kit, has been tested in our laboratory for its ribbon forming capacity. Various block sizes, concentrations of the softening agent polyethylene glycol 400 (PEG), and tissue types have been examined to determine the optimal conditions for ribbon formation. Although unmodified LKB Historesin is capable of forming ribbons, these ribbons often break. The addition of PEG to the embedding solution enhances ribbon formation. When sectioning with glass knives the best results are achieved with the addition of 0.2 ml of PEG/5.0 ml of embedding medium. A conventional AO rotary microtome can be used to produce ribbons if, in addition to the added PEG (optimal concentration 0.25-0.30 per 5 ml of embedding medium) a thin layer of dental wax is added to the upper and lower surfaces of the block. Ribbons form more easily on microtomes, such as the LKB Historange, that have a retractable specimen arm. If serial sections are to be produced it is very important that the upper and lower faces of blocks be parallel.

Acrylates↗

PubMed2004

Incorporation of polymer microspheres within fibrin scaffolds for the controlled delivery of FGF-1.

The purpose of this work was to examine the feasibility of a hybrid scaffold in which fibroblast growth factor-1 (FGF-1)-encapsulated microspheres are embedded within a fibrin gel. Such a tissue-engineered scaffold could be incorporated into surgical procedures to promote healing while simultaneously delivering therapeutic agents that promote angiogenesis. Fibrin has been extensively studied as an adhesive in plastic and reconstructive surgery and the enhancement of wound healing with embedded growth factors is desirable. We report the release of a fluorescently-labeled model protein, bovine serum albumin (BSA-FITC), from poly(D,L-lactic-co-glycolic acid) microspheres embedded in the fibrin scaffold. The protein release was found to be significantly delayed as compared to microspheres alone during the initial 24 h of release. Additionally, FGF-1 was examined for efficient incorporation into these scaffolds as a potential mitogen for fibroblasts. The optimal concentration of FGF-1 in the media that enhanced NIH-3T3 fibroblast proliferation over 48 h was determined to be 0.1 microg/ml. The release of FGF-1 from microspheres embedded in fibrin gels was compared to FGF-1-encapsulated microspheres alone. The release of FGF-1 from the microsphere/scaffolds was delayed as compared to the release of FGF-1 from microspheres alone. This novel hybrid fibrin/microsphere scaffold is a feasible delivery system for growth factors.

Animals↗

PubMed1996

Evaluation of handling methods in the histological diagnosis of Helicobacter pylori: the effect of filter paper.

OBJECTIVES: Few studies have evaluated the handling methods used in the histological diagnosis of Helicobacter pylori. Filter paper has conventionally been used as a receptacle for the biopsy specimen before fixation. The aim of this study was to determine the presence of any effect caused by the use of filter paper. METHODS: The study population consisted of 104 consecutive patients undergoing endoscopic examination. Two antral biopsy specimens from the same area were obtained from each patient. One specimen was put onto a piece of filter paper, and the other into a plastic case. The specimens were fixed overnight in buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin and Giemsa. A direct smear was also prepared from 77 patients by vigorously rubbing the filter paper on a glass slide and staining it with Giemsa. RESULTS: The detection rate of H. pylori was 47.1% (49 of 104) for the filter paper method, 56.7% (59 of 104) for the plastic case method, and 57.7% (60 of 104) for either of the two methods. Of the 60 positive patients, 11 filter paper specimens were negative, whereas only one plastic case specimen was negative. Statistical analysis revealed a significant difference between the two groups (p < 0.01). On the amount of H. pylori, the filter paper method showed a significantly lower grade than the plastic case method (p < 0.05). In the Giemsa-stained smears, H. pylori was identified in 17 (22.1%) of the 77 patients studied. CONCLUSIONS: Use of filter paper may decrease the sensitivity for detection of H. pylori infection. We recommend not using filter paper in the histological diagnosis of H. pylori.

Biopsy↗

PubMed1992

An atlas of glycine- and GABA-like immunoreactivity and colocalization in the cochlear nuclear complex of the guinea pig.

The distribution and colocalization of gamma-aminobutyric acid (GABA)- and glycine-like immunoreactivity in the cochlear nuclear complex of the guinea pig have been studied to produce a light microscopic atlas. The method used was based on post-embedding immunocytochemistry in pairs of 0.5-micron-thick plastic sections treated with polyclonal antibodies against conjugated GABA and glycine respectively. Immunoreactive cells, presumably short axon neurones, predominated in the dorsal cochlear nucleus, with mostly single-GABA-labelled cells in the superficial layer, double-labelled in the middle, and single-glycine-labelled in the deep layers. A few large single-glycine-labelled cells, interpreted as commissural neurons, occurred in the ventral nucleus. Scattered double-labelled cells, probably Golgi cells, were seen in the granule cell domain. Immunolabeled puncta of all three staining categories occurred in large numbers throughout the complex, apposed to somata and in the neuropil, showing a differential distribution onto different types of neuron. Three immunolabeled tracts were noted: the tuberculoventral tract, the commissural acoustic stria, and the trapezoidal descending fibres. Most of the fibres in these tracts were single-labelled for glycine, although in the last mentioned tract single-GABA- and double-labelled fibres were also found. Some of the immunolabeled cell types described here are proposed as the origins of the similarly labelled puncta and fibres on the basis of known intrinsic connections.

Animals↗

PubMed2002

Tracking the harmonic response of magnetically-soft sensors for wireless temperature, stress, and corrosive monitoring.

This paper describes the application of magnetically-soft ribbon-like sensors for measurement of temperature and stress, as well as corrosive monitoring, based upon changes in the amplitudes of the higher-order harmonics generated by the sensors in response to a magnetic interrogation signal. The sensors operate independently of mass loading, and so can be placed or rigidly embedded inside nonmetallic, opaque structures such as concrete or plastic. The passive harmonic-based sensor is remotely monitored through a single coplanar interrogation and detection coil. Effects due to the relative location of the sensor are eliminated by tracking harmonic amplitude ratios, thereby, enabling wide area monitoring. The wireless, passive, mass loading independent nature of the described sensor platform makes it ideally suited for long-term structural monitoring applications, such as measurement of temperature and stress inside concrete structures. A theoretical model is presented to explain the origin and behavior of the higher-order harmonics in response to temperature and stress.

Corrosion↗

PubMed2006

A novel endoscopic approach to brachytherapy in the management of Hilar cholangiocarcinoma.

OBJECTIVES: Traditionally, biliary brachytherapy sources are placed percutaneously via transhepatic drains or endoscopically via nasobiliary tubes (NBT). Another ERCP is needed for stent replacement after NBT removal. The aim of this study was to determine the feasibility and safety of endoscopic transpapillary insertion of irradiation sources through 10-Fr stents. METHODS: Medical records of Mayo Clinic Rochester patients undergoing biliary brachytherapy for hilar cholangiocarcinoma (CCA) were reviewed. Patients were part of a treatment protocol with curative intent including external beam radiation therapy (4,500 cGy), radiation sensitization (5-FU), and low dose rate (LDR) brachytherapy (<3,000 cGy) followed by liver transplantation. The 10-Fr biliary stent placed across the malignant biliary stricture was directly cannulated using a radiopaque (192)Ir embedded ribbon within a 300-cm long, 5.1-Fr plastic sheath. After withdrawal of the endoscope, the external end of the brachytherapy catheter was rerouted transnasally and secured. Each patient was hospitalized in a shielded room up to 24 h after which the brachytherapy catheter was removed by hand. RESULTS: Between 1999 and 2004, 32 patients underwent biliary brachytherapy via endoscopically placed 10-Fr plastic stents (mean age 50.6 yr, 69% PSC, bilateral brachytherapy catheters 28.1%). The technical complication observed was immediate brachytherapy catheter displacement (7 of 32, 22%) managed by prompt brachytherapy catheter repositioning. CONCLUSION: LDR biliary brachytherapy administration via endoscopically placed biliary stents is technically feasible and appears reasonably safe in select patients with unresectable perihilar CCA. Unlike NBTs, stents can potentially be placed in bilateral ductal systems to accommodate dual brachytherapy catheters when indicated.

Bile Duct Neoplasms↗

PubMed1992

An in vitro assessment of the extent of caries under small occlusal cavities.

Many clinicians take for granted that occlusal caries which is just visible as a cavity is extended (deep) into the dentine. This study was aimed at quantifying this opinion. The study was carried out with 60 molars containing small but visible occlusal cavities. After taking bite-wing radiographs the crowns were separated from the roots and embedded. 700-microns sections were cut and glued on plastic sheets. X-ray pictures were taken of the sections which were scored by independent examiners. The bite-wings provided inaccurate estimates of the extent of caries. Radiographs of the sections revealed that about 25% of the molars had caries which reached just to the dentino-enamel junction, while the remaining 75% showed caries extending far into the dentine.

Dental Caries↗

PubMed1981

Oxygen gradients cause pattern orientation in Dictyostelium cell clumps.

We have investigated the formation of the prestalk-prespore pattern in Dictyostelium discoideum. Pattern formation occurs in clumps of Dictyostelium cells embedded in agar under a 100% oxygen atmosphere. Agar embedding allows us to control spatially the environment surrounding the cell clumps. Our results suggest that the ambient oxygen concentration plays a role in controlling the size of the multicellular mass. Further, oxygen gradients established across clumps embedded in agar or held in holes in a plastic barrier cause orientation of the prestalk-prespore pattern such that the anterior prestalk region forms at the highest end of the gradient. The results also indicate that developing cells have the ability to migrate up a gradient of oxygen.

Agar↗

PubMed1991

Histological preparation of the undecalcified rat otic bulla for mesoscopic observations.

Otic bullas of the rat, obtained by excision and formalin fixed, are successfully embedded in methylmethacrylate by dehydration and subsequent infiltration with plastic under vacuum. Sections 10 microns thick are obtained by cutting the trimmed and sandpapered acrylic blocks on an LKB multirange microtome. The sections are collected on adhesive tape and stained with a Trichrome stain (modified Weigert-van Gieson). Finally, the sections attached to the tape are mounted on microscope slides with glycerin-gelatin and sealed in the same medium. Serial sections are used for three-dimensional graphic reconstruction.

Animals↗

PubMed1992

Staining of semithin tissue sections embedded in HPMA, quetol 523 and MMA.

Various tissues fixed in a mixture of formaldehyde and glutaraldehyde, and embedded in an improved 2-hydroxypropyl methacrylate mixture were employed for studying the fine structures of cells and tissues by light microscopy. The embedding mixture contained Quetol 523 and methyl methacrylate as a plasticizer without a cross-linker. The catalyst was QCU-1. The mixture had a low viscosity, was easy to handle and penetrated readily and completely into the specimen, producing a homogeneous block from which it was easy to cut sections of 1-2 microns in thickness. A wide variety of stains have been employed with such sections and those reported here are hematoxylin-eosin, Azan and PAS. There was excellent preservation of alkaline phosphatase activity. A method of poststaining immunoperoxidase labeling was also applied to the mouse pancreas and examples of staining with insulin are included.

Aminosalicylic Acid↗

PubMed1989

Collagen lattice effects on fibroblast arachidonic acid metabolism.

Fibroblasts are routinely maintained in vitro on tissue culture plastic, in an environment which is devoid of collagen, the most abundant extracellular protein in dermis. Recent work has shown that by seeding fibroblasts into a collagen matrix, many aspects of their metabolism change dramatically: they stop proliferation, organize and contract the collagen matrix, and secrete much larger quantities of the usual extracellular matrix components. Because so many fibroblast functions are dramatically altered by the presence of the collagen matrix, matrix effects on fibroblast metabolism of arachidonic acid were examined. The studies presented here show that during the period of matrix contraction, metabolism of arachidonate to prostaglandins by fibroblasts is increased sixfold compared to cells plated on plastic, and that this increase is correlated with contraction but does not regulate it. The increase in prostaglandin synthesis is due in part to an increased new synthesis of the rate-limiting enzyme in prostaglandin synthesis, cyclooxygenase. No change in the profile of products the fibroblasts synthesize from arachidonate is induced by the presence of the matrix. After the lattice contraction is complete, the basal arachidonate metabolism of matrix-embedded cells have the same capacity to synthesize PGE2 in response to IL-1 as do cells grown on plastic. However, the response to the hormone agonist bradykinin by the matrix-embedded cells is present on day 1 but not on day 3, the time when cells grown on plastic are most responsive. These data indicate that while basal prostaglandin metabolism is unaffected in quiescent fibroblasts which have been embedded in a collagen matrix, response to hormone agonists may be greatly attenuated. The changes in the metabolism of arachidonate which occur during the process of matrix contraction and organization may play a part in the regulation of wound repair.

Arachidonic Acid↗

PubMed1983

[Release of water-soluble active agents from polymer embeddings. 2. The significance of the manufacturing process-dependent macrostructure of the embedded dosage from an active agent release].

When compressed tablets were produced, it was found that, owing to plastic deformation, the polymers flowed round the active agent particles, dependently on their elastic modulus and ball thrust hardness. A log-log plot of active agent liberation against porosity as a function of pressing pressure yielded a linear relationship. The embedding of active agents in liquid phase separation products by coacervation causes that the liberation of the active agents depends on their wettability by the high-colloid phase. The wetting behaviour of the high-colloid phase is controlled by the relative ratio of the dipole moments of the solvent and the non-solvent or, if these dipole moments are equal, by the hydrogen bridge parameter according to Gordy. In cases where the embedding of active agents via the state of the solution of the polymers necessitates the removal of the solvent, the temperature at which the removal is performed may be of importance to the liberation of the active agent. When the solvent is removed at a temperature above its boiling point, the liberation rate is likely to increase, especially with lowboiling solvents.

Chemistry, Pharmaceutical↗