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PubMed2002

Measurements of lead in human tibiae. A comparison between K-shell x-ray fluorescence and electrothermal atomic absorption spectrometry.

The aim of this study was to validate 109Cd-based K-shell x-ray fluorescence measurements against atomic absorption spectrometry (AAS) measurements of core and surface tibia lead. The lead content of nine adult human cadaver tibiae was measured using 109Cd-based K-shell x-ray fluorescence (XRF) spectrometry and the results compared to measurements obtained using electrothermal atomization atomic absorption spectrometry following acid digestion. Each tibia was divided into nine cross-sectional segments, which were further separated into tibia core and surface samples for the AAS analytical measurements. Proximal-distal variability in tibia lead concentration as determined by AAS was previously described for both surface and core segments and was found to decrease towards the ends of the tibia, in contrast to XRF in which lead was found to increase towards the tibia ends. The effect of this contrasting behaviour on the agreement between XRF and AAS measurements was examined. Lead concentrations determined by AAS ranged from 3 to 19 microg of lead per gram of dry weight bone (microg g(-1)) for tibia core and from 5 to 32 microg g(-1) for tibia surface. Lead concentrations determined by XRF ranged from 2 to 35 microg g(-1) dry weight. No statistically significant difference was found between mean XRF-measured concentrations and mean surface lead concentrations measured by AAS, but XRF significantly overestimated tibia core lead concentrations by between 5 and 8 microg g(-1).

Cadmium Radioisotopes↗
PubMed2005

Developmental competence of somatic cell nuclear transfer embryos reconstructed from oocytes matured in vitro with follicle shells in miniature pig.

The developmental competence of domestic pig oocytes that were transferred to somatic cell nuclei of miniature pig was examined. A co-culture system of oocytes with follicle shells was used for the maturation of domestic pig oocytes in vitro. Co-cultured oocytes progressed to the metaphase II stage of meiosis more quickly and more synchronously than non co-cultured oocytes. Oocytes were enucleated and fused with fibroblast cells of Potbelly miniature pig at 48 h of maturation. The blastocyst formation rate of nuclear transfer (NT) embryos using cocultured oocytes (24%) was significantly higher (p < 0.05) than that of non-co-cultured oocytes (13%). Cleaved embryos at 48 h after nuclear transfer using co-cultured oocytes were transferred to the oviducts of 14 Göttingen miniature pigs and four Meishan pigs. Estrus of all Göttingens returned at around 20-31 days of pregnancy. Two of the four Meishans became pregnant. Three and two cloned piglets were born after modest number of embryo transfer (15 and 29 embryos transferred), respectively. These results indicated that oocytes co-cultured with follicle shells have a high developmental competence after nuclear transfer and result in full-term development after embryo transfer.

Animals↗
PubMed1987

The effect of centrifugation on the rapid detection of adenovirus in shell vials.

Monoclonal antibody, specific for the adenovirus group-reactive hexon antigen, was used for the detection of this agent by immunofluorescence 24 and 48 hours after inoculation of HEp-2 cell monolayers in 1-dram shell vials after low-speed centrifugation (700 X g, 30 minutes). Of 31 adenovirus isolates, 16 (sensitivity, 52%) and 30 (sensitivity, 97%) were detected after incubation for 24 hours and 48 hours, respectively. All adenovirus strains were detected in conventional tube cell cultures but required an average of four days incubation. The shell vial assay is rapid, sensitive, and specific and can be easily implemented in laboratories with cell culture experience.

Adenoviruses, Human↗
PubMedDate not supplied

Inheritance of the general shell color in the scallop Argopecten purpuratus (Bivalvia: Pectinidae).

Although some external coloration and pigmentation patterns in molluscan shells may be attributable to environmental factors, most variation in these phenotypic characters depends on uncomplicated genetic mechanisms. Genetic research on inheritance of color variations in the north-Chilean scallop (Argopecten purpuratus) has now been expanded to analyze color segregation in juvenile scallops produced under controlled conditions employing self- and cross-fertilization. Calculations from the results were used for comparison with different numerical models based on Mendelian inheritance, and results were also obtained on the inheritance of a dorsoventral white line often observed on the left (upper) valve in this species. The results confirmed the hereditary basis for color variation in the shell of this scallop, suggesting a simple, dominant model of epistasis to explain the distribution of the different color variants observed (purple, brown, orange, yellow, and white). The presence of the white line may be controlled by a recessive allele with simple Mendelian traits on a locus distinct from those that control color variation.

Animals↗
PubMed1999

Two concentric protein shell structure with spikes of silkworm Bombyx mori cytoplasmic polyhedrosis virus revealed by small-angle neutron scattering using the contrast variation method.

The overall and internal structures of the silkworm Bombyx mori cytoplasmic polyhedrosis virus was investigated by small-angle neutron scattering using the contrast variation method. Data were collected in aqueous buffer solutions containing 0, 50, 75, and 100% D2O in the q range of 0.002 to 0.0774 A-1 at 5 degrees C. The radius of gyration at infinite contrast was estimated to be 336 A. The contrast matching point of the virus was determined to correspond to about 50% D2O level, evidence that the virus is composed of protein and nucleic acid. The virus was basically spherical and had a diameter of about 700 A. The main feature of its structure is the clustering of protein into two concentric shells separated by about 100 A. Most of the RNA moieties are located in the central core and between these two protein shells. However, the distance distribution function P(r) showed a minor distribution beyond a distance of r = 700 A, with a maximum particle distance of the virus of 1350 A. This is indicative of an external structure region with very low scattering density, in addition to the basic spherical structure. This external region is thought to correspond to twelve pyramidal protruding spikes shown by electron microscopic studies.

Animals↗
PubMed2006

Antimicrobial resistance in Salmonella and Escherichia coli isolated from commercial shell eggs.

The development of antimicrobial resistance in bacteria has become a global problem. Isolates of Salmonella and Escherichia coli recovered from shell egg samples, collected at 3 commercial plants, were analyzed for resistance to 16 antimicrobial agents (n=990). Eggs were sampled by rinsing in a saline solution. Pooled samples were preenriched in buffered peptone water and then selectively isolated using standard broths and agars. Salmonella-positive isolates were serogrouped immunologically before being serotyped. Enterobacteriaceae were enumerated from individual samples using violet red bile glucose agar plates. Escherichia coli were identified biochemically from presumptive Enterobacteriaceae isolates. Salmonella and generic E. coli antimicrobial-susceptibility testing was conducted using a semiautomated broth microdilution system. More resistance was observed in the Salmonella isolates (n=41) than in the E. coli isolates (n=194). Salmonella Typhimurium was the most prevalent (69.0%) serotype and demonstrated the greatest multiple resistance. Salmonella Kentucky, the least prevalent (5.0%) serotype recovered, was the most susceptible. Although 34.1% of the Salmonella serotypes were susceptible to all antimicrobial agents, 60.1% were resistant to 11 or more compounds. Many Salmonella isolates exhibited resistance to tetracycline (63.4%), nalidixic acid (63.4%), and streptomycin (61.0%). Most E. coli isolates (73.2%) were susceptible to all antimicrobial drugs. Many E. coli isolates exhibited resistance to tetracycline (29.9%), streptomycin (6.2%), and gentamicin (3.1%). Only 1% of the E. coli isolates were resistant to 4 antimicrobial agents. These data indicate that shell eggs can harbor resistant foodborne and commensal bacteria; among Salmonella isolates, resistance was serotype-dependent.

Animals↗
PubMed2000

Molecular cloning and functional characterization of a vasotocin receptor subtype that is expressed in the shell gland and brain of the domestic chicken.

In chickens, oviposition is correlated with increased plasma levels of the neurohypophysial hormone vasotocin, and vasotocin stimulates contraction of uterine strips in vitro. A gene encoding a vasotocin receptor subtype that we have designated the VT1 receptor was cloned from the domestic chicken. The open reading frame encodes a 370-amino acid polypeptide that displays seven segments of hydrophobic amino acids, typical of guanine nucleotide-protein-coupled receptors. Other structural features of the VT1 receptor include two potential N-linked glycosylation sites in the extracellular N-terminal region, a conserved aspartic acid in transmembrane domain 2 that is found in nearly all guanine nucleotide-protein-coupled receptors, and two potential protein kinase C phosphorylation sites in the third intracellular loop and C-terminal tail. Expressed VT1 receptors in COS7 cells bind neurohypophysial hormones with the following rank order of potency: vasotocin congruent with vasopressin > oxytocin congruent with mesotocin > isotocin. In addition, the expressed VT1 receptor mediates vasotocin-induced phosphatidylinositol turnover and Ca(2+) mobilization. In the chicken, expression of VT1 receptor gene transcripts is limited to the shell gland (uterus) and the brain. Thus, the VT1 receptor that we have cloned may mediate contractions of the shell gland during oviposition and activate reproductive behaviors known to be stimulated by vasotocin in lower vertebrates.

Amino Acid Sequence↗
PubMed2002

Active heroin administration induces specific genomic responses in the nucleus accumbens shell.

Long-term drug-induced alterations in gene expression underlying neuroplasticity in the nucleus accumbens (NAc) may play a crucial role in relapse behavior in abstinent drug addicts. In this respect, stimulus-induced relapse behavior is considered as the retrieval of stored drug-related information. Because the NAc shell may determine the impact of external and internal stimuli on goal-directed behavior, we compared long-term gene expression in this brain region after active and passive administration of different drugs of abuse. We made use of a preselected set of transcripts that were down-regulated 3 wk after active i.v. heroin self-administration. We found that most of these transcripts were not down-regulated long after passive exposure to the opiate. Most of the active heroin administration-regulated transcripts were also down-regulated in the NAc shell following active cocaine administration (common denominators). As observed with passive administration of heroin, passive exposure to cocaine was found to be relatively ineffective in reducing the expression of these transcripts. This work reveals that active drug consumption during self-administration (instrumental learning) is a crucial psychological factor directing long-term genomic responses in the brain.

Animals↗
PubMed1994

Psychostimulant drugs increase glucose utilization in the shell of the rat nucleus accumbens.

The nucleus accumbens (NAc) is a heterogeneous area, divided into a 'shell' and a 'core' on the basis of morphological and histochemical criteria. Moreover, the two portions have different anatomical connections. In order to test whether the two portions of NAc are functionally distinct, we measured local cerebral glucose utilization in rats administered intravenously with cocaine (1 mg kg-1) or amphetamine (0.5 mg kg-1). The results of the study show that, at these dosages, both drugs increase glucose utilization in the shell, but not in the core of NAc. This differential effect might reflect functional differences between the two portions of NAc, probably relevant to the abuse liability of psychostimulants.

Amphetamine↗
PubMed1996

Right ventricular volume estimation using an ellipsoidal shell model and single-plane magnetic resonance imaging.

RATIONALE AND OBJECTIVES: To investigate whether accurate right ventricular volumes could be obtained using an ellipsoidal shell model with magnetic resonance (MR) image measurements from a single imaging plane. METHODS: An initial retrospective patient study included 10 patients with congenital cardiac defects who had undergone same-day or next-day radiographic contrast ventriculography. An expanded study included MR scans of a total of 29 patients with congenital cardiac defects. Magnetic resonance scans of 10 healthy volunteers were also included in part of the study. Right ventricular volumes were calculated from (1) model-based calculations using single-plane cine MR imaging, and (2) multislice calculations based on contrast angiography. RESULTS: Regression of angiography-based volumes against MR-based volumes showed high correlation (r = 0.97, see = 12.5 mL) and slope near unity. Regression of right against left stroke volumes, both calculated from MR data, showed excellent correlation (r = 0.90, see = 11.6 ml) and slope near unity. CONCLUSIONS: The ellipsoidal shell model can be used to reliably estimate right ventricular volume using single-plane MR images.

Adolescent↗
PubMed1995

Evaluating the benefits of an antihypertensive agent using trials based on event and organ damage: the Systolic Hypertension in the Elderly Long-term Lacidipine (SHELL) trial and the European Lacidipine Study on Atherosclerosis (ELSA).

AIMS: To assess the benefits of the calcium antagonist lacidipine on the prevention of cardiovascular events and the prevention of organ damage in two long-term clinical trials. SYSTOLIC HYPERTENSION IN THE ELDERLY LONG-TERM LACIDIPINE (SHELL) TRIAL: In the SHELL trial, the efficacy of lacidipine-based treatment is to be compared with that of thiazide-like diuretic (chlorthalidone)-based treatment in elderly patients with isolated systolic hypertension. The incidence of cardiovascular mortality and cardiovascular morbidity over a 5-year period are endpoints. EUROPEAN LACIDIPINE STUDY ON ATHEROSCLEROSIS (ELSA) TRIAL: In the ELSA trial, the effects of lacidipine-based treatment and beta-blocker (atenolol)-based treatment on the development and progression of carotid atherosclerosis are to be assessed in hypertensive patients. The primary endpoint of this study is the rate of change in the thickness of the carotid artery wall, measured with B-mode ultrasound.

Antihypertensive Agents↗
PubMed1984

Synthesis of a metallothionein-like protein by developing turkey embryos maintained in long-term, shell-less culture.

Turkey embryos were maintained in long-term, shell-less culture to the age of 17 days. At this time, 10 cultures were given saline (controls), and 10 cultures were given 30 micrograms zinc in saline (+Zn). In addition, all cultures received 5 microCi each of [35S]cystine and 65Zn dissolved in the saline and applied to the chorioallantoic membrane. After a further 20 h of incubation, no significant differences were found for embryo, liver, or yolk sac weights nor for relative liver size, hematocrit, serum protein, or serum concentrations of zinc and copper for the control and + Zn cultures. The addition of zinc to the cultures significantly (p less than 0.01) elevated hepatic and yolk sac cytosol 65Zn and zinc concentrations. More than 70% of the increased 65Zn and zinc in the cytosol of liver and yolk sac could be accounted for as that bound to a low-molecular-weight metallothionein (MT)-like protein. Added zinc significantly (p less than 0.01) increased the incorporation of [35S]cystine and 65Zn into the MT-like protein from liver and yolk sac indicating de novo synthesis of this protein. Liver and yolk sac MT-like proteins eluted from DEAE Sephadex A-25 columns as a single predominant species. The synthesis of an MT-like protein by liver and yolk sac suggests a role in embryonic zinc homeostasis. Moreover, shell-less culture of the avian embryo appears to be a useful method for studying zinc metabolism during periods of embryonic growth and development.

Animals↗
PubMed1991

Ballistic trauma to the abdomen: shell fragments versus bullets.

Two-hundred ninety-nine patients who sustained penetrating ballistic trauma to the abdomen were divided into two groups: Group A consisted of 133 patients with shell fragment injuries from mortar artillery and Group B of 166 patients with bullet injuries from rifles and automatic or semiautomatic weapons. Both groups were analyzed retrospectively in order to compare the extent of injury and outcome. In Group A, the findings at laparotomy were negative in 15 of 133 patients (10%) compared with 9 of 166 patients (5%) in Group B (p less than 0.05). The most commonly injured abdominal organs in Group A were the colon (42%), liver (22%), small bowel (20%), stomach (14%), diaphragm (11%), spleen (10%), major vessels (40%) [corrected], and kidney (9%). The abdominal organs commonly injured in Group B were the colon (50%), small bowel (41%), liver (33%), major vessels (20%), diaphragm (17%), stomach (15%), spleen (15%), and kidney (15%). Associated extra-abdominal injuries were present in 26% of Group A patients and in 21% of Group B patients (p greater than 0.05) [corrected]. Major postoperative complications occurred in 7.5% and 8.4% of the patients in Group A and Group B, respectively (p less than 0.05). Perioperative mortality was 2.3% in Group A versus 7.2% in Group B (p less than 0.01). Our data suggest that high energy bullets to the abdomen cause higher tissue penetration and a greater blast effect than shell fragments.

Abdominal Injuries↗
PubMed2001

The cortical shell architecture of human cervical vertebral bodies.

STUDY DESIGN: An anatomic study of cervical vertebral bodies. OBJECTIVES: To provide quantitative information on the cortical shell architecture of the middle and lower cervical vertebral bodies. SUMMARY OF BACKGROUND DATA: Some external dimensions have been measured, but little quantitative data exists for the cortical shell architecture of the vertebral bodies of the cervical spine. METHODS: Twenty-one human cervical vertebral bodies (C3-C7) were sectioned along parasagittal planes into five 1.7-mm thin slices for each vertebra. Radiographs of each slice were digitized, and external and internal dimensions were measured. Averages and standard deviations were computed. Single factor analysis of variance was used to determine significant (P < 0.05) differences between the vertebral levels. RESULTS: The superior endplate was thickest in the posterior region (range 0.74-0.89 mm) and thinnest in the anterior region (range 0.44-0.56 mm). The inferior endplate was thickest in the anterior region (range 0.61-0.81 mm) and thinnest in the posterior region (range 0.49-0.62 mm). In the central region, the superior endplate (range 0.42-0.58 mm) was thinner than the inferior endplate (range 0.53-0.64 mm). Variation with vertebral level was dependent on the dimension studied. CONCLUSIONS: Comprehensive quantitative anatomic data of the middle and lower cervical vertebral bodies have been obtained. This may be useful in improving the understanding of the three-column and other vertebral-fracture theories, the fidelity of the finite element models of cervical spine, and the designs of surgical instrumentation.

Cadaver↗
PubMed2002

Power of shell-rapping signals influences physiological costs and subsequent decisions during hermit crab fights.

Understanding the costs of signals used in fights is the key to understanding decisions made by contestants. Hermit crabs use shell rapping. This is a clearly defined agonistic signal, which can be quantified in temporal terms and in the power of the key shell-rapping signal component. We examine the relationship between the power expended by attacking hermit crabs and their consequent lactate levels. High power expenditure over the whole fight leads to high lactate, and attackers give up when lactate is high. Some defenders give up early in fights, particularly if the power of raps in early bouts they receive is high. These defenders and those not allowed to fight have low glucose, but those that successfully resist eviction have high glucose. Glucose is mobilized in an attempt to resist; nevertheless, some defenders that attempt resistance are still evicted by persistent attackers. Thus, early power of the signal is a major determinant of success for attackers, albeit at a cost. These data show the link between power, repetition of a signal, metabolic consequences and decisions of contestants in fights. The different activities, decisions and costs of the two roles are not adequately described by existing models of contests.

Aggression↗
PubMed2003

Trans-shell infection by pathogenic micro-organisms reduces the shelf life of non-incubated bird's eggs: a constraint on the onset of incubation?

Many birds initiate incubation before clutch completion, which results in asynchronous hatching. The ensuing within-brood size disparity often places later-hatched nestlings at a developmental disadvantage, but the functional significance of the timing of the onset of incubation is poorly understood. Early incubation may serve to maintain the viability of early-laid eggs, which declines over time owing to the putative effects of ambient temperature. An unexplored risk to egg viability is trans-shell infection by micro-organisms. We experimentally investigated the rate and magnitude of microbial trans-shell infection of the egg, and the relative effects of ambient temperature and micro-organisms on hatching success. We show that infection of egg contents is prevalent and occurs within the time required to lay a clutch. The probability of infection depends on the climatic conditions, the exposure period and the phylogenetic composition of the eggshell microbiota. We also demonstrate that microbial infection and ambient temperature act independently to reduce egg viability considerably. Our results suggest that these two factors could affect the onset of avian incubation in a wide range of environments.

Analysis of Variance↗
PubMed1993

Electron microscopic evidence for budding process-independent assembly of double-shelled rotavirus particles during passage through endoplasmic reticulum membranes.

Slowing down of the maturation process of human rotavirus particles on ice allowed the clear demonstration of two different assembly pathways through the endoplasmic reticulum (ER) membrane. One was the 'enveloped' and single-shelled (ss) particle assembly pathway, in which a transient envelope is acquired through the budding of subviral particles from the cytoplasm to the ER lumen, and later these 'enveloped' particles are released as ss particles in the ER lumen. The other was a double-shelled particle assembly pathway by which subviral particles acquire the outer capsid proteins during their transport across the ER membrane.

Animals↗
PubMed2003

Human rhabdomyosarcoma cells for rapid detection of enteroviruses by shell-vial assay.

The ability of the RD (rhabdomyosarcoma) and MRC-5 cell-lines to detect enteroviruses in 33 clinical samples (cerebrospinal fluid, stools and throat swabs) was evaluated. The samples had previously tested enterovirus-positive by traditional tube-culture and had been frozen after their initial processing. By traditional tube-culture, 100 and 85 % of samples were positive for enterovirus in RD and MRC-5 cells, respectively. By rapid shell-vial assay, 94 and 45.5 % were positive after 48 h incubation in RD and MRC-5 cells, respectively. RD cells supported growth of all enterovirus serotypes, whereas MRC-5 cells were not able to detect any of the three coxsackieviruses that were found (one coxsackievirus A9 and two coxsackievirus B5). The shell-vial assay with RD cell-lines may be a useful tool for rapid diagnosis of enteroviral infection.

Cerebrospinal Fluid↗