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PubMed1988

Detection of IgM antibody to cytomegalovirus and rapid diagnosis of this virus infection by the shell vial assay.

Multiple serum specimens from 10 patients with known cytomegalovirus (CMV) infections and 498 sera consecutively submitted to the laboratory for the diagnosis of CMV infection were tested for anti-CMV IgM after treatment with goat anti-human IgG and QAE-Sephadex A50 column chromatography. Specimens from all 10 patients were positive for IgM after treatment with anti-IgG, but only 8 after the column procedure. Anti-CMV IgM was detected in 23 of 498 (4.6%) specimens pretreated with anti-IgG but in only 12 (2.4%) of these samples after the sera was passed through QAE-Sephadex A50 columns. Anti-CMV IgM was detected exclusively in 2 sera after QAE-Sephadex A50 column treatment (sensitivity, 83%) and in 13 specimens pretreated with anti-IgG sera (specificity, 97%). Serology (IgG and IgM) was compared with the shell vial cell culture assay and histology for providing the first evidence of CMV infection in 28 liver transplant patients. CMV infection was detected initially by the rapid shell vial assay (24) or histology (3) in 27 (96%) of these patients. Detection of anti-CMV IgM in these patients had little value for rapid diagnosis of these infections, and suggests that serology should be recommended mainly for the diagnosis of primary CMV infections in localities in which the rapid shell vial assay is not available.

Antibodies, Viral↗

PubMed1980

The critical spherical shell in enzymatic fast reaction systems.

As we go more deeply into the theoretical analysis and actual calculations for enzymatic fast reaction systems, the concept of the critical shell would naturally be confronted with. In this paper, a formula is presented to estimate the thickness of the critical shell. An on such a basis, we have made calculations and discussed the influences of various factors such as short-range force, long-range force, activation energy and cavity-active site upon the thickness of the critical spherical shell.

Binding Sites↗

PubMed1992

An intracrystalline chromoprotein from red brachiopod shells: implications for the process of biomineralization.

1. The red colour of some terebratulid brachiopod shells is caused by a small chromoprotein that occurs within the calcium carbonate matrix of the shell. 2. This carotenoid-protein complex was isolated from within the calcite shell of three different brachiopod genera and may therefore be involved in the process of biomineralization. 3. The apparent molecular weight of this protein, as judged by SDS-PAGE, is 6.5 kDa. 4. The partial N-terminal amino acid sequence of the protein is virtually identical in three different brachiopod genera, indicating homology. 5. Two carotenoids are present in Terebratella sanguinea: canthaxanthin and the tentatively identified monoacetylinic analogue of astaxanthin.

Amino Acid Sequence↗

PubMed1996

Densitometrical analysis of opioid receptor ligand binding in the human striatum--I. Distribution of mu opioid receptor defines shell and core of the ventral striatum.

Changes in opioid neurotransmission have been implicated in several basal ganglia-related neurological and psychiatric disorders. To gain a better insight into the opioid receptor distribution in the normal human striatum, we examined in post mortem brain the distribution of the mu opioid receptor using ligand binding of [3H]O-ala2-N-methyl-phe4, gly-ol5-enkephalin. Our results indicate at the regional level the presence of a dorsal-to-ventral high-to-low density gradient in the striatum, with lowest densities in the ventral one-third of the putamen and in the nucleus accumbens. At the subregional level, the nucleus accumbens shows two major types of heterogeneities. First, low vs intermediate binding densities distinguish the core and shell subdivisions, respectively. The low-density core and intermediate-density shell regions extend into the putamen and are therefore characteristic for the entire ventral striatum. The second type of heterogeneity is formed by small areas located along the ventral contours of the nucleus accumbens and putamen that display the highest binding density of the entire striatum. Since these areas can also be recognized in the distribution patterns of other markers and in the cytoarchitecture, they appear to possess a separate identity. To emphasize their special neurochemical characteristics we propose the description "neurochemically unique domains in the accumbens and putamen". The present results, with the difference between core and shell of the ventral striatum as the most prominent outcome, together with the notion that the connectional relationships and neurochemical organization of the striatum are very heterogeneous, suggest a strong regional functional differentiation for mu receptor function in the human striatum.

Adult↗

PubMed1988

Detection of cytomegalovirus in clinical specimens using shell vial centrifugation and conventional cell culture.

Shell vial centrifugation and conventional cell culture methods for detecting cytomegalovirus (CMV) were compared in clinical specimens. Our data confirm that the shell vial centrifugation method is more sensitive and rapid than conventional cell culture; however, due to the shell vial method's problems with toxicity to the fibroblast monolayer, both methods must be performed if all specimens positive for CMV are to be detected.

Cytomegalovirus↗

PubMedDate not supplied

Correlation of urine pH with the detection of cytomegalovirus by the shell vial technique.

The influence of the pH of urine on the detection of cytomegalovirus (CMV) by the shell vial assay was evaluated. The pH values of 295 urine specimens ranged from 4.7 to 8.5 (mean 6.3) and were not significantly different in culture-positive versus culture-negative samples. None of the urine specimens appeared to be toxic for the cells used in the shell vial assay. We recommend inoculation of urine specimens into shell vials without adjustment of pH.

Cytomegalovirus↗

PubMedDate not supplied

Antiviral susceptibility testing of cytomegalovirus from primary culture using shell vial assay to detect the late viral antigen.

Susceptibility testing of 68 cytomegalovirus (CMV) peripheral blood isolates to Ganciclovir (DHPG) and 11 blood isolates to Foscarnet (PFA), was performed on primary culture isolates using the shell vial assay methodology (SVA-IFA, that is, quantitation of fluorescent focus units, FFUs), with an anti-CMV monoclonal antibody to the late viral antigen. A positive reaction in monolayer cultures of MRC-5 cells was characterized by cytoplasmic fluorescence with inclusions at both or more commonly off one end of the elongated fibroblast nucleus. Isolates from conventional MRC-5 tube cultures displaying a 1+ (10% cytopathic effect) were inoculated into shell vials containing DHPG concentrations of 0, 1.5, 3, 6, 12, or 24 microliters/ml shell vials containing 400, 500, 800, or 1200 microM PFA. The optimal readability of monolayers (expressed as FFUs per monolayer) occurred at 96 h after treatment with DHPG and at 36-48 h with PFA. Resistance to DHPG was determined at the concentration of antiviral agent necessary to reduce the number of FFUs to 90% or 50% of the control [that is, the 90% minimum inhibitory concentration (MIC90) or MIC50]. Six of 68 isolates showed an MIC90 > 12 or an MIC50 > 1.5 microgram/ml, and were considered DHPG resistant. Three of the six isolates were from AIDS patients with late-stage disease who had never received DHPG therapy. All but one (specimen 2400) DHPG-resistant isolates revealed MIC90 values to a PFA concentration of 500 microM, which is considered an achievable peak plasma level in patients undergoing PFA therapy. The single DHPG- and FPA-resistant isolate was obtained from a patient displaying marked clinical resistance to both drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗

PubMed1996

Diagnosis of cytomegalovirus (CMV) infection in pediatric transplant patients by the antigenemia, shell vial, and conventional culture assays performed on blood: correlation with CMV disease.

BACKGROUND: Human cytomegalovirus (CMV) is a significant cause of morbidity and mortality in transplant recipients. Isolation of CMV from blood leukocytes (CMV viremia) is considered predictive of CMV disease in transplant recipients. Therefore, investigation of methods for the rapid detection of CMV in the blood is important for diagnosis and management of these patients. OBJECTIVE: To compare three techniques for the diagnosis and monitoring of CMV infection in a pediatric transplant population through the quantitative detection of CMV in peripheral blood leukocytes (PBL). METHODS: Serial blood specimens were obtained for most patients. After separation of the PBL from each specimen, aliquots of the PBL were used for direct detection of CMV antigenemia by immunoperoxidase staining of acetone-fixed cells (CMV-vue kit, INCSTAR), and by immunofluorescence staining of formaldehyde-fixed cells (Complete 1C3 kit, Biosoft Argene). PBL were also inoculated into conventional cell culture tubes and shell vials. Patients' medical records were reviewed to ascertain the clinical significance of the results. RESULTS: A total of 154 specimens obtained from 38 pediatric transplant recipients were evaluated. CMV was detected in 16 specimens obtained from eight patients: 11 specimens were found positive with the CMV-vue kit, 10 with the Complete 1C3 kit, four by conventional culture, and one by the shell vial assay. Seven of the eight patients with CMV-positive PBL had clinical signs and other laboratory evidence of active CMV infection. In general, a high-level antigenemia was demonstrated in the presence of clinical disease, but there were exceptions. CONCLUSIONS: The two antigenemia kits were more sensitive than conventional culture and the shell vial assay for the detection of CMV in the blood of pediatric transplant patients. Our results suggest that CMV antigenemia is a sensitive and specific rapid method for the diagnosis and monitoring of CMV infection in our patient population.

Journal Article↗

PubMed2005

Cementation of a metal-inlay polyethylene liner into a stable metal shell in revision total hip arthroplasty.

The purpose of this study was to evaluate the results of liner cementation into a stable acetabular shell using a metal-inlay polyethylene liner in 39 revision total hip arthroplasties. After an average of 2.8 years, 1 cemented liner dislodged from its metal shell at a postoperative 4 years. In the other 38 hips, mean Harris hip scores improved from 65 preoperatively to 86.9 at the final follow-up. Eighteen patients were rated as having excellent results, 17 as good, and 3 as fair. There were no changes in cup position and no cases of osteolytic lesion progression around the femoral and acetabular components in the last follow-up radiographs. Metal-inlay polyethylene liner cementation into a stable acetabular shell was found to provide an alternative option with short-term excellent results, and it also offers more liner options, the preservation of bone stock, and lower surgical morbidity.

Acetabulum↗

PubMed2004

Dissociation of core and shell single-unit activity in the nucleus accumbens in free-choice novelty.

Core and shell regions of the nucleus accumbens (NAcc) have been implicated in different aspects of goal-directed behavior. To assess these differences at the neuronal level, we evaluated core and shell single-unit activity in eight rats during one-trial, free-choice entry into a novel compartment. Changes in firing rate during approach of (orientation toward) and entry into (nose cross) novelty were assessed relative to a pre-novelty baseline when the animals were behaviorally active. Increases and decreases in neuronal activity were recorded in both regions during both phases of the novelty response. The regional distribution of these responses, however, was significantly different during the approach phase with roughly equal proportions of neuronal excitations (8/29) and inhibitions (6/29) in core but a shift away from excitation (2/40) toward inhibition (12/40) in shell. No regional differences emerged during subsequent approach of the familiar compartment from the novel chamber or during entry to either the novel or familiar compartment. Taken together, our results during approach to free-choice novelty indicate a regional dissociation in NAcc firing rate may play a role in appetitive behavior.

Action Potentials↗

PubMed2005

Latent inhibition is disrupted by nucleus accumbens shell lesion but is abnormally persistent following entire nucleus accumbens lesion: The neural site controlling the expression and disruption of the stimulus preexposure effect.

Latent inhibition (LI) is the proactive interference of repeated nonreinforced preexposure to a stimulus with subsequent performance on a learning task involving that stimulus. The present experiments investigated the role of the nucleus accumbens (NAC) in LI. LI was measured in a thirst motivated conditioned emotional response procedure with low or high number of conditioning trials, and in two-way active avoidance procedure with the stages of preexposure and conditioning taking place in the same or different contexts. Sham-lesioned rats showed LI with low but not high number of conditioning trials and if preexposure and conditioning took place in the same context but not if the context was changed between the stages. Lesion to the shell subregion of the NAC disrupted LI but LI was preserved in rats with a combined lesion to the NAC shell and core subregions. Moreover, rats with a combined shell-core lesion persisted in showing LI in spite of high number of conditioning trials and in spite of context change. These results show that the NAC is not essential for the acquisition of LI but rather plays a key role in regulating the expression of LI. Moreover, they suggest that the two subregions of the NAC contribute competitively and cooperatively to this process, selecting the response appropriate to the stimulus-no event or the stimulus-reinforcement association in conditioning.

Analysis of Variance↗

PubMed2006

Electrolytic lesions of a discrete area within the nucleus accumbens shell attenuate the long-term expression, but not early phase, of sensitization to cocaine.

Repeated exposure to cocaine leads to behavioral sensitization, which is the augmentation of the locomotor response to a subsequent exposure to the drug. The nucleus accumbens (NAc), a major termination site of dopaminergic neurons, is believed to be involved in behavioral sensitization and studies have demonstrated that the NAc shell can be split into five zones of analysis; the vertex, arch, cone, intermediate and ventrolateral zones [Todtenkopf MS, Stellar JR. Assessment of tyrosine hydroxylase immunoreactive innervation in five subregions of the nucleus accumbens shell in rats treated with repeated cocaine. Synapse 2000;38:261-70]. Several reports show cocaine-induced c-fos expression particularly in the intermediate zone after 14, but not 2, drug-free days following repeated cocaine administration, suggesting that this region may be involved in sensitization and particularly in the later phase of expression, versus the earlier phase of sensitization. Bilateral electrolytic lesions of the intermediate zone were made in two groups of rats, which were then repeatedly exposed to cocaine (15 mg/kg, twice/day for 5 days). One group was subsequently given a single cocaine challenge injection (15 mg/kg) after 14 drug-free days, while the other group was challenged after only 2 drug-free days. Two sham surgery groups in which an electrode was lowered but no current was passed served as controls. Results show that lesioned animals as well as sham controls exhibited behavioral sensitization to the drug. However, following a 14-day drug-free period, the lesioned animals showed significant reduction in sensitization, compared to sham controls. Together these findings suggest that the intermediate zone of the NAc shell is indeed involved in the expression phase of behavioral sensitization to cocaine.

Analysis of Variance↗

PubMed2004

Structure and expression of an unusually acidic matrix protein of pearl oyster shells.

We report identification and characterization of the unusually acidic molluscan shell matrix protein Aspein, which may have important roles in calcium carbonate biomineralization. The Aspein gene (aspein) encodes a sequence of 413 amino acids, including a high proportion of Asp (60.4%), Gly (16.0%), and Ser (13.2%), and the predicted isoelectric point is 1.45; this is the most acidic of all the molluscan shell matrix proteins sequenced so far, or probably even of all known proteins on earth. The main body of Aspein is occupied by (Asp)(2-10) sequences punctuated with Ser-Gly dipeptides. RT-PCR demonstrated that the transcript of aspein is expressed at the outer edge of the mantle, corresponding to the calcitic prismatic layer, but not at the inner part of the mantle, corresponding to the aragonitic nacreous layer. Our findings and previous in vitro experiments taken together suggest that Aspein is responsible for directed formation of calcite in the shell of the pearl oyster Pinctada fucata.

Amino Acid Sequence↗

PubMed2004

Enzyme immobilization in novel alginate-chitosan core-shell microcapsules.

Alginate-chitosan core-shell microcapsules were prepared in order to develop a biocompatible matrix for enzyme immobilization, where the protein is retained either in a liquid or solid core and the shell allows permeability control over substrates and products. The permeability coefficients of different molecular weight compounds (vitamin B2, vitamin B12, and myoglobin) were determined through sodium tripolyphosphate (Na-TPP)-crosslinked chitosan membrane. The microcapsule core was formed by crosslinking sodium alginate with either calcium or barium ions. The crosslinked alginate core was uniformly coated with a chitosan layer and crosslinked with Na-TPP. In the case of calcium alginate, the phosphate ions of Na-TPP were able to extract the calcium ions from alginate and liquefy the core. A model enzyme, beta-galactosidase, was immobilized in the alginate core and the catalytic activity was measured with o-nitrophenyl-beta-D-galactopyranoside (ONPG). Change in the activity of free and immobilized enzyme was determined at three different temperatures. Na-TPP crosslinked chitosan membranes were found to be permeable to solutes of up to 17,000Da molecular weight. The enzyme loading efficiency was higher in the barium alginate core (100%) as compared to the calcium alginate core (60%). The rate of ONPG conversion to o-nitrophenol was faster in the case of calcium alginate-chitosan microcapsules as compared to barium alginate-chitosan microcapsules. Barium alginate-chitosan microcapsules, however, did improve the stability of the enzyme at 37 degrees C relative to calcium alginate-chitosan microcapsules or free enzyme. This study illustrates a new method of enzyme immobilization for biotechnology applications using liquid or solid core and shell microcapsule technology.

Alginates↗

PubMed2006

Crystal structure characterization of nautilus shell at different length scales.

In this work, we studied the shell structure of the Nautilus pompilius Linnaeus by using analytical techniques of scanning (SEM) and transmission electron microscopy (TEM) and X-ray diffraction. The main objective of this study is the structural characterization of Nautilus shell at different length levels, from micron to nano-scale. The results were also used to try to determine the shell structure mechanism of formation. The information obtained in this work will place our particular knowledge a closer step to understand how self-assembly works in nature, and will increase the opportunities of using this information in the future synthesis of new advanced materials.

Crystallization↗

PubMed2006

Polymer hollow fiber three-dimensional matrices with controllable cavity and shell thickness.

Hollow fibers find useful applications in different disciplines like fluid transport and purification, optical guidance, and composite reinforcement. In tissue engineering, they can be used to direct tissue in-growth or to serve as drug delivery depots. The fabrication techniques currently available, however, do not allow to simultaneously organize them into three-dimensional (3D) matrices, thus adding further functionality to approach more complicated or hierarchical structures. We report here the development of a novel technology to fabricate hollow fibers with controllable hollow cavity diameter and shell thickness. By exploiting viscous encapsulation, a rheological phenomenon often undesired in molten polymeric blends flowing through narrow ducts, fibers with a shell-core configuration can be extruded. Hollow fibers are then obtained by selective dissolution of the inner core polymer. The hollow cavity diameter and the shell thickness can be controlled by varying the polymers in the blend, the blend composition, and the extrusion nozzle diameter. Simultaneous with extrusion, the extrudates are organized into 3D matrices with different architectures and custom-made shapes by 3D fiber deposition, a rapid prototyping tool which has recently been applied for the production of scaffolds for tissue engineering purposes. Applications in tissue engineering and controlled drug delivery of these constructs are presented and discussed.

Biocompatible Materials↗

PubMed2006

Shell-crosslinked Pluronic L121 micelles as a drug delivery vehicle.

Pluronic block copolymers (PBCs) have been shown to reverse multidrug resistance (MDR) by inhibiting the P-glycoprotein (P-gp) pump in cancer cells. One of the problems encountered with the use of PBCs is that the micelles disassociate at low concentrations. The study focused on the stabilization of PBC L121 micelles by the formation of crosslinks within their outer shells. To form crosslinks, the two terminal alcohols on L121 were first chemically converted into aldehydes (L121-CHO) using the Dess-Martin periodinane. Diamine compounds were then used to bridge the converted aldehyde termini on L121-CHO via conjugated Schiff bases. After crosslinking, the morphology of the L121 micelles remained spherical in shape and the mean particle sizes of the micelles before and after crosslinking were comparable (100nm). After exposure of MDR KBv cells to free rhodamine-123 (R123), the accumulation of R123 in cells was limited due to the function of P-gp. In contrast, crosslinking of L121 micelles within their outer shells significantly reduced their critical micelle concentration and greatly enhanced their stability, while maintaining their ability to inhibit P-gp function in resistant cells. The results indicated that the L121 micelles with shell crosslinks may be useful as a drug delivery vehicle for cancer chemotherapy.

Animals↗

PubMed2006

Magnetic shells for gastrointestinal endoscopic capsules as a means to control their motion.

Wireless endoscopic video capsules are becoming largely used today for non-invasive explorations of the digestive tube. Traditional types of such capsules present a major drawback: their motion can not be controlled, since they proceed by means of the visceral peristalsis only. In order to enable a wireless control of their motion, this paper describes a new concept based on the use of external magnetic fields. The proposed technique exploits magnetic shells to be applied to traditional capsules prior to their use. The shells are capable of interacting with an imposed external magnetic field, providing a means to control the capsule movement and orientation. This solution is readily and cheaply applicable to any commercial endoscopic capsule, avoiding internal modifications. The paper reports results of preliminary bench tests. Prototype elastic shells made of a silicone elastomer mixed with magnetic particles were fabricated and tested with the Given Imaging M2A capsule in simplified experimental conditions. These tests permitted to demonstrate translations, rotations and roto-translations of the capsule/shell complex onto pieces of bovine tissues.

Capsule Endoscopes↗