Restorative procedures after root canal therapy.

One of the most common indications for veterinary dental restoration involves replacing tooth structure after a root canal procedure. Special considerations are necessary due to the interaction of the restorative material with materials used to obturate the root canal. The restoration must provide a hermetic seal of the pulp chamber, as well as restore function.

Predicting sprint kinematic parameters from anaerobic field tests in physical education students.

The relations among kinematic parameters measured during the first 10 seconds of 100-m sprint and anaerobic tests were studied in 22 male physical education students. During the first 10 seconds of the sprint, the position of the runners was "continuously" measured with a laser telemeter. Maximal acceleration (Amax), maximal velocity (Vmax), and time to reach Vmax (tVmax) were derived from position data.

Effects of two low-dose oral contraceptives containing ethinylestradiol and either desogestrel or levonorgestrel on serum lipids and lipoproteins with particular regard to LDL size.

This study was designed to determine the effects of two low-dose oral contraceptives, most frequently given in our area, monophasic desogestrel/ethinylestradiol (DG/EE) and triphasic levonorgestrel/ethinylestradiol (LNG/EE), on lipoprotein parameters, especially LDL particle size and HDL subclass distribution (determined by lipid-stained 2%-20% polyacrylamide gradient gel electrophoresis) in 37 healthy normolipidemic women aged 19 to 27 years. Lipid and lipoprotein parameters were measured before the start of treatment and in the third month of oral contraceptive use. Results reflected the estrogen-progestin balance.

Investigation of the roles of Ca(2+) and InsP(3) diffusion in the coordination of Ca(2+) signals between connected hepatocytes.

Glycogenolytic agonists induce coordinated Ca(2+) oscillations in multicellular rat hepatocyte systems as well as in the intact liver. The coordination of intercellular Ca(2+) signals requires functional gap-junction coupling. The mechanisms ensuring this coordination are not precisely known.

Hierarchical organization of calcium signals in hepatocytes: from experiments to models.

The proper working of the liver largely depends on the fine tuning of the level of cytosolic Ca(2+) in hepatocytes. Thanks to the development of imaging techniques, our understanding of the spatio-temporal organization of intracellular Ca(2+) in this - and other - cell types has much improved. Many of these signals are mediated by a rise in the level of inositol 1,4,5-trisphosphate (InsP(3)), a second messenger which can activate the release of Ca(2+) from the endoplasmic reticulum.

Activation of the liver glycogen phosphorylase by Ca(2+)oscillations: a theoretical study.

Cytosolic calcium plays a crucial role as a second messenger in cellular signalling. Various cell types, including hepatocytes, display Ca(2+)oscillations when stimulated by an extracellular signal. However, the biological relevance of this temporal organization remains unclear.

[Marchiafava-Bignani disease of good prognosis. Two cases].

Background: Marchiafava-Bignami disease or corpus callosum necrosis, is an uncommon complication of chronic alcoholism. Prognosis is severe.

Case Reports: Two young adults with chronic alcoholism who developed Marchiafava-Bignami disease initially improved clinically.

The frequency encoding of pulsatility.

Examples of pulsatile signalling abound in intercellular communication, suggesting that this phenomenon represents a major function of biological rhythms. Pulsatile signals can be encoded in terms of their frequency and prove more efficient than monotonous ones whenever constant stimulation induces desensitization of target cells. We address the main examples of frequency encoding of pulsatility, besides those of neuronal nature.

Mechanism of receptor-oriented intercellular calcium wave propagation in hepatocytes.

Intercellular calcium signals are propagated in multicellular hepatocyte systems as well as in the intact liver. The stimulation of connected hepatocytes by glycogenolytic agonists induces reproducible sequences of intracellular calcium concentration increases, resulting in unidirectional intercellular calcium waves. Hepatocytes are characterized by a gradient of vasopressin binding sites from the periportal to perivenous areas of the cell plate in hepatic lobules.

From calcium blips to calcium puffs: theoretical analysis of the requirements for interchannel communication.

In the cytoplasm of cells of different types, discrete clusters of inositol 1,4,5-trisphosphate-sensitive Ca(2+) channels generate Ca(2+) signals of graded size, ranging from blips, which involve the opening of only one channel, to moderately larger puffs, which result from the concerted opening of a few channels in the same cluster. These channel clusters are of unknown size or geometrical characteristics. The aim of this study was to estimate the number of channels and the interchannel distance within such a cluster.

[Effects of oral contraceptive preparations and smoking on lipoprotein repartition].

We studied the effect of oral contraceptives and smoking on the lipid profile of 251 women and 72 men, 20-29-year-old. In women, taking estroprogestatives, cholesterol, triglycerides, apoproteins AI and B were higher than in controls; HDL-cholesterol was not modified. Lipoprotein analyses in polyacrylamide gradient gel exhibited an increase of the HDL3 fraction at the expense of the HDL2 fraction, with a reduced LDL size.

CaM kinase II as frequency decoder of Ca2+ oscillations.

In many cell types, Ca2+ signals are organized in the form of repetitive spikes. The frequency of these intracellular Ca2+ oscillations increases with the level of stimulation, suggesting the existence of a frequency encoding phenomenon. The question arises as to how the frequency of Ca2+ oscillations can be decoded inside the cell.

Prevention of periodontal disease.

Periodontal disease is the most common disease affecting adult dogs and cats. It is also a very preventable disease. The insidious nature of the disease and requirement for the pet owner to be actively involved make client and public education absolutely vital.

Theoretical insights into the mechanism of spiral Ca2+ wave initiation in Xenopus oocytes.

Spiral waves of intracellular Ca2+ have often been observed in Xenopus oocytes. Such waves can be accounted for by most realistic models for Ca2+ oscillations taking diffusion of cytosolic Ca2+ into account, but their initiation requires rather demanding and unphysiological initial conditions. Here, it is shown by means of numerical simulations that these spiral Ca2+ waves naturally arise if the cytoplasm is assumed to be heterogeneous both at the level of the synthesis and metabolism of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and at the level of the distribution of the Ins(1,4, 5)P3 receptors.

Stochastic simulation of a single inositol 1,4,5-trisphosphate-sensitive Ca2+ channel reveals repetitive openings during 'blip-like' Ca2+ transients.

Confocal microscope studies with fluorescent dyes of inositol 1,4,5-trisphosphate (InsP3)-induced intracellular Ca2+ mobilization recently established the existence of 'elementary' events, dependent on the activity of individual InsP3-sensitive Ca2+ channels. In the present work, we try by theoretical stochastic simulation to explain the smallest signals observed in those studies, which were referred to as Ca2+ 'blips' [Parker I., Yao Y.

Link between fertilization-induced Ca2+ oscillations and relief from metaphase II arrest in mammalian eggs: a model based on calmodulin-dependent kinase II activation.

Mammalian eggs are ovulated in metaphase II of meiosis, in a state characterized by high levels of cyclin B and of active maturation promoting factor (MPF). This arrest is mediated by an activity referred to as cytostatic factor (CSF) which prevents the degradation of cyclin. Fertilization triggers a train of Ca2+ spikes which is responsible for the decrease in activity of both MPF and CSF.

Understanding dental plaque; biofilm dynamics.

A biofilm is a well organized community of cooperating microorganisms. Biofilms predictably form in nature, in artificial environments, and on medically implanted prostheses and indwelling venous catheters. They also form on tooth surfaces in the form of dental plaque.

Simulations of the effects of inositol 1,4,5-trisphosphate 3-kinase and 5-phosphatase activities on Ca2+ oscillations.

Inositol 1,4,5-trisphosphate (Ins-1,4,5-P3) is responsible for Ca2+ mobilization in response to external stimulation in many cell types. The latter phenomenon often occurs as repetitive Ca2+ spikes. In this study, the effect of the two Ins-1,4,5-P3 metabolizing enzymes (Ins-1,4,5-P3 3-kinase and 5-phosphatase) on the temporal pattern of Ca2+ oscillations has been investigated.

Complex intracellular calcium oscillations. A theoretical exploration of possible mechanisms.

Intracellular Ca(2+) oscillations are commonly observed in a large number of cell types in response to stimulation by an extracellular agonist. In most cell types the mechanism of regular spiking is well understood and models based on Ca(2+)-induced Ca(2+) release (CICR) can account for many experimental observations. However, cells do not always exhibit simple Ca(2+) oscillations.

Modeling spiral Ca2+ waves in single cardiac cells: role of the spatial heterogeneity created by the nucleus.

Excitation-contraction coupling in cardiomyocytes is known to rely on the Ca(2+)-induced Ca2+ release mechanism. This autoamplification process is also very apparent when voltage-clamped or Ca(2+)-overloaded myocytes exhibit fast-propagating Ca2+ waves. Although most of the fronts are planar, some adopt a spiral shape, revealing additional characteristics about the excitability and structure of the cardiac cell (P.

Quantal release, incremental detection, and long-period Ca2+ oscillations in a model based on regulatory Ca2+-binding sites along the permeation pathway.

Quantal release, incremental detection, and oscillations are three types of Ca2+ responses that can be obtained in different conditions, after stimulation of the intracellular Ca2+ stores by submaximum concentrations of inositol 1,4,5-triphosphate (InsP3). All three phenomena are thought to occur through the regulatory properties of the InsP3 receptor/Ca2+ channel. In the present study, we perform further analysis of the model (Swillens et al.

Phospholipase C in mouse oocytes: characterization of beta and gamma isoforms and their possible involvement in sperm-induced Ca2+ spiking.

This study involved an investigation of the role of phospholipase C (PLC) in generating repetitive Ca2+ spikes at fertilization. Using a PCR-based strategy we have demonstrated that mouse oocytes have mRNA coding for PLC beta 1, PLC beta 3 and PLC gamma isoenzymes. Furthermore, immunodetection of PLC gamma 1 using monoclonal antibodies reveals that PLC gamma 1 protein is present in mature mouse oocytes, ruling out the possibility that mRNA was being transcribed but not expressed.

Tooth splinting for severely mobile mandibular incisor teeth in a dog.

Periodontal disease, in its advanced stages, causes tooth mobility. The tooth movement further damages the periodontium, accelerating the disease process leading to tooth loss. Dental splinting can provide coaptive stability to the teeth as an important component of a periodontal treatment plan.

Crown amputation with intentional root retention for advanced feline resorptive lesions--a clinical study.

Whole tooth extraction is generally considered to be the treatment of choice for teeth with advanced feline external odontoclastic resorptive lesions. These teeth often have both a weakened, brittle crown and radicular ankylosis. These two factors cause frustration and sometimes complications during attempts at extraction.