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PubMed2003

[Biological banks of the prospective cohort PRIME Study].

BACKGROUND: Cardiovascular disease is the leading cause of mortality in westernized countries. Learning more about the cause of coronary heart disease (CHD) is an essential step in the search for effective CHD prevention, both at the individual and population levels. Prospective cohort studies are particularly well suited to the study of risk markers. However, the high cost of mounting such studies, along with the newer hypotheses generated during the period of follow-up necessitates the use of plasma and serum banks for analyses of many biological parameters. METHODS: The prospective, cohort PRIME Study has recruited 10,592 men, aged 50-59 years in France and Northern Ireland, to establish new risk markers for CHD. A plasma serum bank was established comprising 240,000 samples, either in straws or tubes, which have been stored in liquid nitrogen for over 5 years. The use of straws was required to store the largest number of aliquots in the smallest possible space. Storage validation was carried out for a number of key parameters. The validity of freezing of plasma in straws was established for a number of key measurements under investigation. Simultaneously, a DNA bank was set up to facilitate genetic analyses. In contrast to the DNA bank, which enables the performance of a very large number of analyses on a small amount of material, the plasma/serum bank has to be managed very frugally, requiring laboratories to use the smallest volume possible in each analysis. RESULTS AND CONCLUSION: Problems and difficulties solved during building and use of biological banks are presented. The initial results obtained using this plasma bank have demonstrated its validity.

Blood Banks↗
PubMed1997

An overview on the effectiveness of natural family planning.

Recent years have witnessed important developments in natural family planning (NFP), which is based on the observation of fertile and infertile periods of the menstrual cycle, so that the couple is able to know when sexual intercourse may lead to a pregnancy. A review of the main studies regarding the effectiveness of NFP showed a decrease in the Pearl Index and life table values from the early 1980s to date, indicating that progress both in the teaching and in the application of these contraception, methods has been achieved. The main cause of lack of success seems to be the misapplication of NFP rules, whereas the errors due to the method itself are few. Furthermore, it seems that the symptothermal method might give better results than the ovulation method, even though no comparative study has been carried out, and that the first studies on the lactational amenorrhea method show encouraging results. Finally, it seems that NFP is best suited for 'spacers' of pregnancies, rather than for 'limiters'. Indeed, the former are more likely to show good compliance, since the sexual abstinence periods are limited and an unwanted pregnancy is not regarded as a completely negative event.

Clinical Trials as Topic↗
PubMed1989

Gotthard Bülau and closed water-seal drainage for empyema, 1875-1891.

Optimal treatment of pleural empyema remains controversial to the present day. In the preantibiotic era, surgical thinking favored early and aggressive drainage of closed-space infections, but the dynamics of the pleural space were poorly understood and open pneumothorax generally was considered the necessary price of surgical drainage. Against bitter opposition, revision of the dogma of early open drainage was achieved in 1918 by Evarts Graham and his associates on the US Army's Empyema Commission. Unacceptable mortality rates for early drainage were brought under control through a treatment program of repeated tapping, with surgical drainage only after loculation had occurred. Paradoxically, closed water-seal drainage for empyema had been used by a German internist, Gotthard Bülau, as early as 1875. His technique was published in 1891, 27 years before the report of the Empyema Commission. As a closed system, it would have been suited to empyema drainage in either the early diffuse or the loculated stages. Thoracotomy was not possible at the time, and Bülau probably could not foresee the future importance of his method to surgery.

Drainage↗
PubMedDate not supplied

Experimental aortic stenosis and corresponding left ventricular hypertrophy in sheep.

Left ventricular hypertrophy (LVH) is an independent cardiac risk factor. A simple standard experimental model of inducing LVH for further studies using experimental aortic stenosis in sheep was performed. The aim of this study is to describe animal-specific requirements as well as perioperative therapy, postoperative care, and the use of echocardiography for routine follow-up examinations. Supracoronary aortic banding was performed in 55 female sheep at an age of 6 to 8 months. General anesthesia and an antero-lateral thoracotomy were used. The objective was to achieve pressure gradients of 20 to 30 mm Hg. In addition a 4th intercostal space rib window was created to improve echocardiographic vision. The operations were completed successfully in all animals. Intraoperatively, little severe arrhythmia occurred. During the follow-up interval of 8 +/- 1.3 months, 8 animals died, due to incomplete perforation of the ascending aorta (3), chronic heart failure (2), pericardial cyst (1), and respiratory failure and infection (2). All remaining animals were amenable for further studies. Severe LVH was diagnosed with routine echocardiography on follow-up. Thus, experimental aortic stenosis in sheep is a safe and relatively simple technique to generate stable LVH. Echocardiography is an easy tool for follow-up evaluations. Due to low complication rates, the sheep model is well suited for further research in LVH.

Animals↗
PubMed2000

Monte Carlo simulation of dose distributions from a synchrotron-produced microplanar beam array using the EGS4 code system.

Microbeam therapy is established as a general concept for brain tumour treatment. A synchrotron based x-ray source was chosen for experimental research into microbeam therapy, and therefore new simulations were essential for investigating the therapy parameters with a proper description of the synchrotron radiation characteristics. To design therapy parameters for tumour treatments, the newly upgraded LSCAT (Low energy SCATtering) package of the EGS4 Monte Carlo simulation code was adapted to develop an accurate self-written user code for calculating microbeam radiation dose profiles with a precision of 1 microm. LSCAT is highly suited to this purpose due to its ability to simulate low-energy x-ray transport with detailed photon interactions (including bound electron incoherent scattering functions, and linear polarized coherent scattering). The properties of the synchrotron x-ray microbeam, including its polarization, source spectrum and beam penumbra, were simulated by the new user codes. Two concentric spheres, an inner sphere, defined as a brain, and a surrounding sphere, defined as a skull, represented the phantom. The microbeam simulation was tested using a 3 x 3 cm array beam for small treatment areas and a 6 x 6 cm array for larger ones, with different therapy parameters, such as beam width and spacing. The results showed that the microbeam array retained an adequate peak-to-valley ratio, of five times at least, at tissue depths suitable for radiation therapy. Dose measurements taken at 1 microm resolution with an 'edge-on' MOSFET validated the basics of the user code for microplanar radiation therapy.

Brain Neoplasms↗
PubMed1997

The neural coding of stereoscopic depth.

Stereopsis is a process by which the visual system gauges the relative depth of objects in three-dimensional space by measuring minute positional differences between left and right images. According to the standard notion, this information is thought to be encoded in the primary visual cortex by differences in receptive field (RF) positions for the two eyes. We have developed in alternative model by which stereoscopic information is coded and transformed through a hierarchical chain of processing in the primary visual cortex. Initially, first-order neurons of the visual cortex, simple cells, encode depth information by a scheme based on differences in internal receptive field structure between left and right eyes. Further abstraction of information is achieved by a subset of second-order neurons, complex cells, that are well suited for the detection of depth information in a manner unaffected by positional variations of objects. We review physiological evidence from studies of the cat and monkey that are relevant to the proposed scheme.

Animals↗
PubMed2000

Development of peltate glandular trichomes of peppermint.

Cryofixation and conventional chemical fixation methods were employed to examine the ultrastructure of developing peltate glandular trichomes of peppermint (Mentha x piperita). Our results are discussed in relation to monoterpene production and the mechanism of essential oil secretion. Peltate glands arise as epidermal protuberances (initials) that divide asymmetrically to produce a vacuolate basal cell, a stalk cell, and a cytoplasmically dense apical cell. Further divisions of the apical cell produce a peltate trichome with one basal cell, one stalk cell, and eight glandular (secretory) disc cells. Presecretory gland cells resemble meristematic cells because they contain proplastids, small vacuoles, and large nuclei. The secretory phase coincides with the separation and filling of the sub-cuticular oil storage space, the maturation of glandular disc cell leucoplasts in which monoterpene biosynthesis is known to be initiated, and the formation of extensive smooth endoplasmic reticulum at which hydroxylation steps of the monoterpene biosynthetic pathway occur. The smooth endoplasmic reticulum of the secretory cells appears to form associations with both the leucoplasts and the plasma membrane bordering the sub-cuticular oil storage cavity, often contains densely staining material, and may be involved with the transport of the monoterpene-rich secretion product. Associated changes in the ultrastructure of the secretory stage stalk cell are also described, as is the ultrastructure of the fragile post-secretory gland for which cryofixation methods are particularly well suited for the preservation of organizational integrity.

Cryopreservation↗
PubMed1994

Efficient sampling of protein sequence space for multiple mutants.

We describe here a method capable of generating a very large population of multiple mutants, the size of which is primarily limited by volume constraints. This method, referred to as recombination-enhanced mutagenesis, combines the power of in vitro mutagenesis with the high frequencies of in vivo recombination that can be achieved using single-stranded transduction systems. The recombination frequency between two mutations separated by as little as 19 amino acids is 0.02; this frequency approaches a value of 0.1 for mutations separated by more than 38 amino acids. Up to 10(8) independent recombinants were generated in 1 ml of an E. coli culture, and this number scales linearly (or better) with increasing volume. To prove the method's effectiveness, we applied it to the problem of reverting multiple mutants of mouse dihydrofolate reductase, which could not be reverted using mutagenesis alone. Thus, given an appropriate screen or selection scheme, recombination-enhanced mutagenesis is well-suited for addressing a range of combinatorially complex problems, such as antigen recognition, enzyme catalysis, protein folding, and transport/transduction across biomembranes.

Animals↗
PubMedDate not supplied

Data-driven analysis approach for biomarker discovery using molecular-profiling technologies.

High-throughput molecular-profiling technologies provide rapid, efficient and systematic approaches to search for biomarkers. Supervised learning algorithms are naturally suited to analyse a large amount of data generated using these technologies in biomarker discovery efforts. The study demonstrates with two examples a data-driven analysis approach to analysis of large complicated datasets collected in high-throughput technologies in the context of biomarker discovery. The approach consists of two analytic steps: an initial unsupervised analysis to obtain accurate knowledge about sample clustering, followed by a second supervised analysis to identify a small set of putative biomarkers for further experimental characterization. By comparing the most widely applied clustering algorithms using a leukaemia DNA microarray dataset, it was established that principal component analysis-assisted projections of samples from a high-dimensional molecular feature space into a few low dimensional subspaces provides a more effective and accurate way to explore visually and identify data structures that confirm intended experimental effects based on expected group membership. A supervised analysis method, shrunken centroid algorithm, was chosen to take knowledge of sample clustering gained or confirmed by the first step of the analysis to identify a small set of molecules as candidate biomarkers for further experimentation. The approach was applied to two molecular-profiling studies. In the first study, PCA-assisted analysis of DNA microarray data revealed that discrete data structures exist in rat liver gene expression and correlated with blood clinical chemistry and liver pathological damage in response to a chemical toxicant diethylhexylphthalate, a peroxisome-proliferator-activator receptor agonist. Sixteen genes were then identified by shrunken centroid algorithm as the best candidate biomarkers for liver damage. Functional annotations of these genes revealed roles in acute phase response, lipid and fatty acid metabolism and they are functionally relevant to the observed toxicities. In the second study, 26 urine ions identified from a GC/MS spectrum, two of which were glucose fragment ions included as positive controls, showed robust changes with the development of diabetes in Zucker diabetic fatty rats. Further experiments are needed to define their chemical identities and establish functional relevancy to disease development.

Algorithms↗
PubMed2002

[What messages did the Norwegian tobacco industry communicate to consumers in its advertising?].

BACKGROUND: A Norwegian official report, NOU 2000: 16, Tort liability for the Norwegian tobacco industry, concludes that Norwegian law and judicial practice allows lawsuits against the tobacco industry for damages. A crucial claim in such suits would be that the industry withheld information on health risks and addiction and instead used advertising messages that undermined the information campaigns initiated after the reports on smoking and health from the U.S. Surgeon-General and the Norwegian Board of Health in 1964. This article reports a study of differences in tobacco advertising in Norway before and after 1964. MATERIAL AND METHODS: A total of 1,945 photographs of advertisements in two popular weekly family magazines over the 1955 to 1975 period were stored in a database along with information on date of publication, size, copy and message, presumed target group, and characteristics of persons and situations shown. RESULT: Up until 1964, advertisement space per year in these magazines totalled 100 dm2 (11 sq. feet). The amount of advertising space then increased up until 1973, to 2,033 dm2 (219 sq. feet). The share featuring women went up from 33 in the 1955-64 period to 62% in 1965-75, when 51% of advertisements showed women smoking while 31% showed men smoking. Pre-1964 advertisements primarily contained information to smokers on price, type of tobacco, packaging and country of origin; after 1964 the advertisements developed a more universal appeal associating smoking with various social situations marked by style, well-being and comfort. The tobacco was said to be pure, fresh, mild and natural, and the filter was claimed to have protective properties. INTERPRETATION: It is probable that the cognitive dissonance created by more health information on smoking after 1964, i.e. the necessary motivation to quit, was reduced as a result of strategic changes in the amount and content of advertising.

Advertising↗
PubMed2001

Cave biosignature suites: microbes, minerals, and Mars.

Earth's subsurface offers one of the best possible sites to search for microbial life and the characteristic lithologies that life leaves behind. The subterrain may be equally valuable for astrobiology. Where surface conditions are particularly hostile, like on Mars, the subsurface may offer the only habitat for extant lifeforms and access to recognizable biosignatures. We have identified numerous unequivocally biogenic macroscopic, microscopic, and chemical/geochemical cave biosignatures. However, to be especially useful for astrobiology, we are looking for suites of characteristics. Ideally, "biosignature suites" should be both macroscopically and microscopically detectable, independently verifiable by nonmorphological means, and as independent as possible of specific details of life chemistries--demanding (and sometimes conflicting) criteria. Working in fragile, legally protected environments, we developed noninvasive and minimal impact techniques for life and biosignature detection/characterization analogous to Planetary Protection Protocols. Our difficult field conditions have shared limitations common to extraterrestrial robotic and human missions. Thus, the cave/subsurface astrobiology model addresses the most important goals from both scientific and operational points of view. We present details of cave biosignature suites involving manganese and iron oxides, calcite, and sulfur minerals. Suites include morphological fossils, mineral-coated filaments, living microbial mats and preserved biofabrics, 13C and 34S values consistent with microbial metabolism, genetic data, unusual elemental abundances and ratios, and crystallographic mineral forms.

Exobiology↗
PubMed1985

Nomograms of the Goldman equation.

Solutions of the Goldman equations for sodium and potassium ions are displayed in nomograms which allow one to determine which values of the variables in the equation (including the activity of the Na/K pump) are compatible with possible steady states of a cell. The nomograms are particularly suited for the study of relative changes of the cell parameters when one or more of them are altered and the cell undergoes a transition from one steady state to another. Special diagrams are presented for finding the changes of the slope conductance (determined at a clamp potential of -80 mV) associated with such transitions. Separate diagrams are given for the cationic component conductance, (gNa + gK), and the anionic component conductance, gCl. The application of the nomograms is illustrated by the exemplary solution of a problem taken from muscle physiology. Further applications of the nomograms are indicated and the limitations of the method are described. The effects of differing activity coefficients in the intra- and extracellular spaces, as well as the contribution of the electrogenic Na/K pump current to the resting potential are discussed.

Cell Physiological Phenomena↗
PubMed1997

The role of sutures and fibrin sealant in wound healing.

Sutures and fibrin sealant are important surgical aids for facilitating wound closure and creating an optimal setting for wound healing. Most commonly, sutures are used to close wounds because suture material provides the mechanical support necessary to sustain closure. A wide variety of suturing material is available, and the surgeon can choose among sutures with a range of attributes to find the one best suited to his or her needs. Considerations when choosing an appropriate suture for wound closure and healing include strength of suture, holding power of tissue, absorbability, risk of infection, and inflammatory reaction associated with the suture material. Other factors to be considered include type of incision, suturing technique, and appearance of wound site. Fibrin sealant, in contrast, is a biologic tissue adhesive that can function as a useful adjunct to sutures. Fibrin sealant can be used in conjunction with sutures or tape to promote optimal wound integrity, or it can be used independently to seal wound sites where sutures cannot control bleeding or would aggravate bleeding. This adhesive can effectively seal tissue planes and eliminate potential spaces. Fibrin sealant has been used clinically in many surgical applications, although an FDA-approved commercially available product does not yet exist in the United States. Clinically, fibrin sealant has resulted in a low rate of infection and has promoted healing. Further study is needed to determine the best fibrin sealant mixtures both to achieve hemostasis and to encourage healing. It may even be desirable to use different sealant formulations for particular clinical situations.

Fibrin Tissue Adhesive↗
PubMed1998

A computational "genome walk" technique to identify regulatory interactions in gene networks.

To delineate the astronomical number of possible interactions of all genes in a genome is a task for which conventional experimental techniques are ill-suited. Sorely needed are rapid and inexpensive methods that identify candidates for interacting genes, candidates that can be further investigated by experiment. The subject of this paper is the application of a novel method to the genome of the yeast Saccharomyces cerevisiae. The method applies to an important class of gene interactions, that is, transcriptional regulation via transcription factors (TFs) that bind to specific enhancer or silencer sites on DNA. The method addresses the question: which of the genes in a genome are likely to be regulated by one or more TFs with known DNA binding specificity? It takes advantage of the fact that many TFs show cooperativity in transcriptional activation which manifests itself in closely spaced TF binding sites. Such "clusters" of binding sites are very unlikely to occur by chance alone, as opposed to individual sites, which are often abundant both in the genome and in promoter regions. Statistical information about binding site clusters in the genome, can be complemented by information about (i) known biochemical functions of the TF, (ii) the structure of its binding site, and (iii) function of the genes near the cluster, to identify genes likely to be regulated by a given transcription factor. Previously, binding sites of well characterized transcription factors in Saccharomyces cerevisiae were analyzed. Here, the method is applied to a somewhat different situation: the yeast DNA binding activity yE2F, similar to the mammalian transcription factor E2F. yE2F has a DNA binding specificity identical to E2F, and its binding site shows UAS activity in a GAL1-based promoter construct. However, despite its high conservation, the in vivo function of yE2F is unknown. The analysis carried out the here suggests candidate genes for regulation by yE2F.

Animals↗
PubMed1974

Red cell membrane permeability deduced from bulk diffusion coefficients.

The permeability coefficients of dog red cell membrane to tritiated water and to a series of[(14)C]amides have been deduced from bulk diffusion measurements through a "tissue" composed of packed red cells. Red cells were packed by centrifugation inside polyethylene tubing. The red cell column was pulsed at one end with radiolabeled solute and diffusion was allowed to proceed for several hours. The distribution of radioactivity along the red cell column was measured by sequential slicing and counting, and the diffusion coefficient was determined by a simple plotting technique, assuming a one-dimensional diffusional model. In order to derive the red cell membrane permeability coefficient from the bulk diffusion coefficient, the red cells were assumed to be packed in a regular manner approximating closely spaced parallelopipeds. The local steady-state diffusional flux was idealized as a one-dimensional intracellular pathway in parallel with a one-dimensional extracellular pathway with solute exchange occurring within the series pathway and between the pathways. The diffusion coefficients in the intracellular and extracellular pathways were estimated from bulk diffusion measurements through concentrated hemoglobin solutions and plasma, respectively; while the volume of the extracellular pathway was determined using radiolabeled sucrose. The membrane permeability coefficients were in satisfactory agreement with the data of Sha'afi, R. I., C. M. Gary-Bobo, and A. K. Solomon (1971. J. Gen. Physiol. 58:238) obtained by a rapid-reaction technique. The method is simple and particularly well suited for rapidly permeating solutes.

Amides↗
PubMed2006

Spin 3/2 Zeeman perturbed NQR in the presence of slow sample rotation.

Theoretical and experimental results are presented for the case of Zeeman perturbed nuclear quadrupole resonance (NQR) using spin-3/2 nuclei with a small Zeeman interaction, gammaB0, while the sample is very slowly rotated. It is found that the decay envelope for a simple two-pulse echo measurement can be strongly affected even though the sample may rotate only a few degrees or less during the course of the measurement. To lowest order the decay envelope can be described using a one dimensional function of the product of gammaB0, the rotation rate, and the square of the pulse spacing. Aside from an indirect and weak dependence on the quadrupole asymmetry parameter, eta, the result is independent of the NQR frequency. Identical results are expected for a stationary sample in a small rotating magnetic field. The effect seen here may be used to advantage to measure rotational motion, for example of particles in fluids, or may be an additional complication for some Zeeman perturbed NQR measurements, including some NQR detection and imaging methods.

Journal Article↗
PubMed2006

Mechano-transduction mediated secretion and uptake of galectin-3 in breast carcinoma cells: implications in the extracellular functions of the lectin.

In the following experiments, we sought to understand the triggering mechanism which propels galectin-3 to be secreted into the extracellular compartment from its intracellular stores in breast carcinoma cells. We also wanted to analyze in greater details the role of galectin-3 in cellular adhesion and spreading. To do this, we made use of two pairs of breast carcinoma cell lines where one of the pair has high expression of galectin-3 and the other low expression of the lectin. We determined that galectin-3 secreted into the conditioned medium of sub-confluent and spread cells in culture was quite low, almost negligible. However, once the cells were detached and rounded up, a mechano-sensing mechanism triggered the rapid secretion of galectin-3 into the conditioned medium. The secretion was constitutive as long as the cells remained detached. Galectin-3 was shown to be actively taken up from the conditioned medium by spreading cells. The cells which express and secrete high levels of galectin-3 adhered and spread much faster on plastic than those with reduced expression. The uptake of galectin-3 according to our data was important in cell spreading because if this process was compromised significantly, cells failed to spread. The data suggested that galectin-3 uptake modulates the adhesion plaques in that cells which express high levels of galectin-3 have thin-dot like plaques that may be suited for rapid adhesion and spreading while cells in which galectin-3 expression is reduced or knocked-down, have thick and elongated plaques which may be suited for a firmer adhesion to the substratum. Recombinant galectin-3 added exogenously reduced the thickness of the adhesion plaques of tumor cells with reduced galectin-3 expression. Taken together, the present data suggest that galectin-3 once externalized, is a powerful modulator of cellular adhesion and spreading in breast carcinoma cells.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1981

CT of blunt abdominal trauma in childhood.

Computed tomography (CT) was performed on 23 children who had sustained moderate or severe blunt abdominal trauma. The major advantages of CT over excretory urography, sonography, and radionuclide imaging include superior anatomic detail and ability to visualize all organs, the peritoneal cavity, and retroperitoneum simultaneously. In suspected renal injury, CT best defines the extent of parenchymal injury and provides an easy method for accurate follow-up when conservative management is elected. Angiography is necessary for direct demonstration of vascular injury, for demonstration of active bleeding, and in therapeutic embolization of active bleeding sites. CT seems well suited to evaluation of the liver and retroperitoneum. Evaluation of the spleen has been satisfactory, but may be less accurate because of potential pitfalls. Duodenal hematomas are best evaluated by the upper gastrointestinal series. For CT scanning of the traumatized child to be of maximum value, intravenous contrast enhancement and meticulous attention to technique is necessary.

Abdominal Injuries↗