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PubMed2006

Determination of some enzymes and macro- and microelements in stallion seminal plasma and their correlations to semen quality.

Seminal plasma is very important for sperm metabolism as well as sperm function and survival and transport in the female genital tract. Analysis of enzyme activities and concentrations of elements can estimate integrity and function of sperm cell membranes. In man much data are available about biochemical analyses of seminal plasma. However, not many studies have been conducted in horses yet. We collected ejaculates from 72 stallions, measured the volume, obtained seminal plasma by centrifugation and examined spermatozoa with light microscopy for motility, concentration, for dead sperm and morphology. Of seminal plasma fluid, we measured activities of aspartate-amino-transferase (AST), gamma-glutamyl-transferase (GGT), alkaline phosphatase (AlP), acid phosphatase (AcP) and lactate-dehydrogenase (LDH) as well as concentrations of sodium (Na(+)), potassium (K(+)), total and ionised calcium (Ca(TOTAL)/Ca(2+)), magnesium (Mg(2+)), phosphate (P), chloride (Cl), copper (Cu), iron (Fe) and zinc (Zn). In addition, correlations among different parameters in light microscopy and seminal plasma were statistically examined by using the Spearman rank correlation coefficient. Median enzyme activities for AST, GGT, AlP, AcP and LDH were 80.0, 7,500, 30,200, 20.0, 81.0 IU/L, respectively. Concentrations of Na(+), K(+), Ca(TOTAL), Ca(2+), Mg(2+), P, Cl were 110.5, 22.1, 2.9, 1.7, 3.1, 1.1 and 114.5 mmol/L, and of microelements Cu, Fe and Zn were 17.8, 1.9 and 13.2 micromol/L, respectively. Furthermore, we found significant correlations between semen volume as well as sperm concentration and AST, GGT, AlP, AcP and LDH as well as Fe and Zn. This made us propose a primary testicular and epididymal origin of these parameters. Significant correlation between GGT and motility may be a sign for its function for cell protection against free radicals. LDH activity significantly correlates with motility and progressive motility, live:dead-ratio and pathomorphology. In our study, LDH seems to be the most predictive enzyme for semen quality. This is the first report about GGT, AcP and LDH activities as well as iron in equine seminal plasma.

Acid Phosphatase↗
PubMed2005

The evolutionary dynamics of endogenous retroviruses.

Endogenous retroviruses (ERVs) are vertically transmitted intragenomic elements derived from integrated retroviruses. ERVs can proliferate within the genome of their host until they either acquire inactivating mutations or are lost by recombinational deletion. We present a model that unifies current knowledge of ERV biology into a single evolutionary framework. The model predicts the possible long-term outcomes of retroviral germline infection and can account for the variable patterns of observed ERV genetic diversity. We hope the model will provide a useful framework for understanding ERV evolution, enabling the testing of evolutionary hypotheses and the estimation of parameters governing ERV proliferation.

Endogenous Retroviruses↗
PubMed1998

Effects of physical connectivity on the representational unity of multi-part configurations.

While physical connection strongly supports perceptual integration of visual elements or parts into single objects, concavities along an object's contour strongly induce segmentation of objects into different parts. By means of a matching task, we examine whether the segmentation of connected parts and the grouping of disconnected parts imply differences in representational unity. All match trials consisted of either two identical configurations or two 180 degrees rotated versions of an otherwise identical configuration, whereas mismatch trials had one misoriented part. Results show that the 180 degrees matches with the physically disconnected parts were relatively slower than similar matches with physically connected parts, although the connections could be minimal (deep concavities, corner to edge connection). This suggests that the mental operation required for the 180 degrees match has more difficulty with the disconnected parts, indicating a measurably lower degree of representational unity.

Adult↗
PubMed1988

Protein intolerance and immunocyte and enterocyte interaction.

Food allergy is an untoward immunologic reaction to food. The number of conditions that need to be considered in the differential diagnosis is large and includes adverse reactions to foods that do not have an immunologic basis. Intestinal immune elements are an integral feature of the intestinal mucosa and, besides modulating gastrointestinal function, represent a significant part of the host's overall immune system. Despite increasing knowledge, the precise disturbances in immune function that lead to the appearance of food allergy are still unclear. Food allergy will remain primarily a clinical diagnosis, relying on history and response to dietary elimination and rechallenge until more specific tests become available.

Dietary Proteins↗
PubMed2003

Grouping local directional signals into moving contours.

We consider how local motion signals are combined to represent the movements of spatially extensive objects. A series of band-pass target dots, whose collective motion defined a moving contour, was positioned within a field of randomly moving noise dots. The visibility of the contours did not depend on the direction of movement relative to local contour orientation unless the contour was constrained to pass through fixation, suggesting that a previously reported advantage for collinear motion trajectories depends on the probability of detecting any of the target elements rather than the integrated contour. Contour visibility was invariant of the spatial frequency of the elements, but it did depend on the speed, number and spacing of elements defining it, as well as the angle and spatial frequency difference between adjacent elements. Local averaging of directional signals is not sufficient to explain these results. The visibility of these moving contours identifies narrow-band grouping processes that are sensitive to the shape defined by the directions of the elements forming the contour.

Humans↗
PubMed2003

Delineation of the regulated Variant Surface Glycoprotein gene expression site domain of Trypanosoma brucei.

The African trypanosome Trypanosoma brucei is protected in the bloodstream of the mammalian host by a dense Variant Surface Glycoprotein (VSG) coat. Although an individual cell has hundreds of VSG genes, the active VSG is transcribed in a mutually exclusive fashion from one of about twenty telomeric VSG expression sites. Expression sites are regulated domains flanked by 50 bp repeat arrays and extensive tracts of repetitive elements. We have integrated exogenous rDNA and expression site promoters upstream of the 50 bp repeats of the VO2 VSG expression site. Transcription from both types of exogenous promoter is downregulated and comparable to promoters targeted into the VSG Basic Copy arrays. We show that the upstream exogenous rDNA promoter escapes VSG expression site control, as switching the downstream VO2 VSG expression site on and off does not affect its activity. Therefore, the 50 bp repeat arrays appear to be the boundary of the regulated expression site domain.

Animals↗
PubMed1997

Selenium: potent stimulator of tyrosyl phosphorylation and activator of MAP kinase.

Selenium, an essential biological trace element, is an integral component of several enzymes, and its use as a nutritional supplement has been popularized recently due to its potential role in low concentrations as an antioxidant and in higher concentrations as an anticancer agent. Selenium has also been reported to act as an insulin-mimetic agent with regard to normalization of blood glucose levels and regulation of some insulin-mediated metabolic processes. Little work, however, has been done concerning the pathway(s) by which this insulin-mimetic action occurs. In this study, we investigated the mechanism by which selenate exhibits insulin-mimetic properties in two different insulin responsive cell types, primary rat hepatocytes and 3T3 L1 adipocytes. We found that two proteins associated with the insulin signal cascade, the beta-subunit of the insulin receptor and IRS-1, increased in tyrosyl phosphorylation in the presence of selenium. The third identified selenium activated signal protein, MAP kinase, has been implicated not only in the insulin signal transduction pathway but also in other growth factor-mediated responses. Using an in-gel activity assay for MAP kinase, we demonstrated that both the p42 and p44 MAP kinases are activated when either hepatocytes or adipocytes are incubated in the presence of selenate. In addition to the activation of these specific proteins, we found that selenium also eventually profoundly affected overall tyrosyl phosphorylation. Our results therefore show that selenium not only increased the phosphorylation of proteins identified in the insulin signal cascade but also affected the overall phosphorylation state of the cell.

Adipocytes↗
PubMed1998

Silicon and matrix macromolecules: new research opportunities for old diseases from analysis of potential mechanisms of breast implant toxicity.

An understanding of the normal and essential integration of the element silicon in biosystems, as well as knowledge of its fundamental chemistry, are crucial to understanding its role in health and disease. Modern organosilicon chemistry, based in part on the artificial silicon-carbon bond, coincided with the emergence of the biomaterials and bioengineering fields fifty years ago, and was thought to be a fortunate coincidence according to conventional wisdom that high-molecular-weight polymeric siloxanes were chemically and biologically inert. These concepts have been challenged by reports of silicone migration and degradation following insertion of gel-filled breast implants, claims of a novel systemic illness appearing in many breast implant recipients, and investigations implicating varied and permeating immunotoxic mechanisms of disease causation by breast devices. The present study develops additional potential pathogenetic ideas based on alterations of cell biochemistry by silicon-containing compounds, and offers correlation of the patients' diverse clinical features with plausable disruption of basic biological processes. This in turn raises new questions concerning everyday environmental exposure, has broad implications for multiple other diseases, can provide alternative directions for future investigative research, and may contribute to the ongoing redefinition of immune dysfunction and inflammation.

Biocompatible Materials↗
PubMed2000

Thyrotropin releasing hormone decreases alcohol intake and preference in rats.

Thyrotropin releasing hormone (TRH) has been reported to reduce stress- and deprivation-induced eating, hypothetically by induction of satiation. Early work demonstrated thyroid extracts reduced alcohol intake, and recent research shows a TRH analog specifically inhibits alcohol preference. We determined whether parenteral administration of TRH reduces alcohol consumption and choice in a manner consistent with a satiation effect. Water-restricted ad lib fed female and male rats (n = 12) were given access to 5% w/v ethanol 0 or 30 minutes after intraperitoneal (i.p.) injection of TRH. TRH (20-40 mg/kg) inhibited alcohol intake only if injected immediately before alcohol access. Inhibition of alcohol intake was reliably accompanied by increased production of fecal boli but not by reliably decreased food intake. Rats given a choice of 2% w/v ethanol and water decreased alcohol preference after TRH (20 mg/kg) but did not reduce total fluid intake. Results are partially consistent with the hypothesis of TRH as one of several functional elements in the integrative neuropeptide control of alcohol consumption via short-term satiation.

Alcohol Drinking↗
PubMed2003

Creating a healing environment for critical care.

Creating a healing environment for critical care requires an organizational as well as personal commitment. An organizational model for health and healing integrates five key elements: common value for the mind-body-spirit approach to wellness and health; patient/family centered relationships; an organizational culture that promotes personal growth; the availability of CAT as well as conventional therapy; and a physical environment that supports healing. CAT strategies to support a physical environment for spirituality and healing were outlined, followed by a discussion of strategies for building capacity for EI to alleviate the emotional labor of nursing and facilitate family centered care.

Animals↗
PubMed2003

Military nursing at the forefront: the Army Forward Surgical Team.

From World War II to current conflicts, history has validated the need for early surgical intervention to save lives and established the need for FSTs. Historically 10% to 15% of soldiers wounded in action require surgery to control hemorrhage and to provide stabilization sufficient for evacuation to a medical treatment facility where definitive care can be provided. Undoubtedly, many lives were saved in past conflicts because resuscitative surgery and care were available a short time after being wounded. The need for surgical stabilization for patients to survive a long evacuation was well-established during military operations such as Operation Desert Storm. Resuscitative surgery capability must be present on the battlefield, and this capability must be able to move with the units the FST is supporting. These two imperatives were the driving force of the creation of the US Army's FSTs: they are light, easily transportable, and able to keep pace with the supported units. FSTs are an integral and essential element in providing surgical care to save soldiers' lives on the modem battlefield. The US military has been involved in more operations and deployments since the end of the Cold War than in the preceding years. FSTs participated in many of these operations and have performed superbly. FSTs will continue to have a critical role in providing combat health service support to soldiers on the battlefield of the twenty-first century, and FST nurses will continue to be an indispensable asset.

Hospitals, Packaged↗
PubMed1998

Construction of biosensors using a gold-binding polypeptide and a miniature integrated surface plasmon resonance sensor.

Surface plasmon resonance (SPR) biosensors were constructed on miniature integrated sensors. Recognition elements were attached to the sensor surface using a gold-binding repeating polypeptide. Biosensors with fluorescyl groups attached to their surfaces were functional for at least 1 month of daily use with little decrease in response to the binding of an anti-fluorescyl monoclonal antibody. The coupling of protein A to the gold-binding polypeptide on the sensor surface enabled the biosensor to detect the binding of antibodies to the protein A and provided a sensor with convertible specificity. The system described herein provides a simple and rapid approach for the fabrication of highly specific, durable, portable and low cost SPR-based biosensors.

Amino Acid Sequence↗
PubMed1999

Containment sensors for the determination of L-lactate and glucose.

This paper reports some new results on enzyme based silicon containment sensors. For the first time an L-lactate sensor in containment technology is presented. Through optimization of the buffer system the stability of the lactate sensor was enhanced and the linear response of over 10 mM was achieved. The glucose sensor has also been optimized for a large linear measurement range exceeding 30 mM. A two-enzyme chip with glucose and lactate sensor elements which were integrated on one silicon chip is presented. The response behaviour of the two-enzyme chip was very similar to the single chip behaviour. No cross-talking effects could be observed. A fabrication process for mass-production is described.

Biosensing Techniques↗
PubMed2003

Genomic islands and the evolution of catabolic pathways in bacteria.

Genes for the degradation of organic pollutants have usually been allocated to plasmid DNAs in bacteria or considered non-mobile when detected in the chromosome. New discoveries have shown that catabolic genes can also be part of so-called integrative and conjugative elements (ICElands), a group of mobile DNA elements also known as genomic islands and conjugative transposons. One such ICEland is the clc element for chlorobenzoate and chlorocatechol degradation in Pseudomonas sp. strain B13. Genome comparisons and genetic data on integrase functioning reveal that the clc element and several other unclassified ICElands belong to a group of elements with conserved features. The clc element is unique among them in carrying the genetic information for several degradation pathways, whereas the others give evidence for pathogenicity functions. Many more such elements may exist, bridging the gap between pathogenicity and degradation functions.

Catalysis↗
PubMed2003

Potential contribution of metformin to the management of cardiovascular disease risk in patients with abdominal obesity, the metabolic syndrome and type 2 diabetes.

With an evolving landscape of a growing number of obese and/or type 2 diabetic patients in our affluent population, the metabolic syndrome has become a major issue because of its impact on cardiovascular disease risk. In this regard, although it is appropriate to aim at a better glycaemic control in type 2 diabetic patients, hyperglycaemia does not appear to be the main culprit responsible for the markedly increased cardiovascular disease risk in this population. Rather, studies have suggested that a cluster of metabolic abnormalities, which includes an atherogenic dyslipidaemic state, an impaired glucose/insulin homeostasis, and a pro-thrombotic and inflammatory profile, substantially increases the risk of coronary heart disease in type 2 diabetic patients in a manner which is partly independent of glycaemic control. These results imply that in order to reduce the risk of atherosclerotic macrovascular disease in type 2 diabetic patients, physicians need not only to focus on a better glycaemic control but also to improve the features of the metabolic syndrome. As a consequence, in order to evaluate the clinical benefits of pharmacotherapy in type 2 diabetic patients, we need to quantify the impact of any pharmacological intervention beyond glucose control. In this context, metformin has been shown to not only contribute to a better glycaemic control but also to induce some weight loss (especially in the visceral depot) which may contribute to the improvement of the features of the metabolic syndrome. Thus, metformin treatment may represent a relevant element of an integrated lifestyle modification-pharmacotherapy to prevent not only type 2 diabetes but also cardiovascular disease.

Abdomen↗
PubMed2004

Five elements for organizational decision-making with an environmental management system.

Environmental management systems (EMSs) are growing in popularity as tools to manage corporate environmental issues. Despite widespread use, existing frameworks for EMSs may not provide organizations with the knowledge needed for decision-making. Through a synthesis of case studies and workshops, we suggest five elements for EMSs to be expanded for organizational decision-making. The five elements are process diagrams, long- and short-term goals linked to strategy, reliable information systems, risk assessment tools, and collaboration of environmental personnel across the organization. These five elements provide decision makers with relevant information linked to business strategy so that the organization can improve performance. The elements can be integrated with an existing EMS or used as a foundation for implementing one.

Conservation of Natural Resources↗
PubMed2006

Diphenyloligothiophene-based dichromophoric macrocycles and their ability to form donor/acceptor complexes.

A series of four dichromophoric rigid macrocycles 6a-6d, two with diphenyloligothiophene chromophores, the other two with more electron-rich diphenyl-EDOT or diphenyl-bis-EDOT chromophores, have been synthesized. The absorption spectrum of the diphenyl-bis-EDOT based macrocycle 6d displayed the most pronounced vibronic resolution with a well-resolved 0-0 transition, indicating a fully planarized geometry of the diphenyl-bis-EDOT chromophores. The (1)H NMR spectra of the macrocycles displayed weak to moderate chemical shifts of characteristic signals upon addition of pi-conjugated oligonitro-9-fluorenone acceptors. X-ray single-crystal analysis showed that columnar pi-stacked donor/acceptor complexes are formed with the stacks composed of alternating donor and acceptor molecules. The stoichiometry of the crystalline, dark-colored complexes was found to be 1:1 by elemental analysis and integration of the (1)H NMR peaks. The complex formation is accompanied by remarkably large Stern-Volmer constants of fluorescence quenching.

Journal Article↗
PubMed1998

Physical link and functional coupling of presynaptic calcium channels and the synaptic vesicle docking/fusion machinery.

N- and P/Q-type calcium channels are localized in high density in presynaptic nerve terminals and are crucial elements in neuronal excitation-secretion coupling. In addition to mediating Ca2+ entry to initiate transmitter release, they are thought to interact directly with proteins of the synaptic vesicle docking/fusion machinery. As outlined in the preceding article, these calcium channels can be purified from brain as a complex with SNARE proteins which are involved in exocytosis. In addition, N-type and P/Q-type calcium channels are co-localized with syntaxin in high-density clusters in nerve terminals. Here we review the role of the synaptic protein interaction (synprint) sites in the intracellular loop II-III (L(II-III)) of both alpha1B and alpha1A subunits of N-type and P/Q-type calcium channels, which bind to syntaxin, SNAP-25, and synaptotagmin. Calcium has a biphasic effect on the interactions of N-type calcium channels with SNARE complexes, stimulating optimal binding in the range of 10-20 microM. PKC or CaM KII phosphorylation of the N-type synprint peptide inhibits interactions with native brain SNARE complexes containing syntaxin and SNAP-25. Introduction of the synprint peptides into presynaptic superior cervical ganglion neurons reversibly inhibits EPSPs from synchronous transmitter release by 42%. At physiological Ca2+ concentrations, synprint peptides cause an approximate 25% reduction in transmitter release of injected frog neuromuscular junction in cultures, consistent with detachment of 70% of the docked vesicles from calcium channels based on a theoretical model. Together, these studies suggest that presynaptic calcium channels not only provide the calcium signal required by the exocytotic machinery, but also contain structural elements that are integral to vesicle docking, priming, and fusion processes.

Action Potentials↗