A dictionary learning approach for spatio-temporal characterization of absence seizures.

OBJECTIVE: This research explores absence seizures using data recorded from different layers of somatosensory cortex of four genetic absence epilepsy rats from Strasbourg (GAERS). Localizing the active layers of somatosensory cortex (spatial analysis) and investigating the dynamics of recorded seizures (temporal analysis) are the main goals of this research. APPROACH: We model the spike discharges of seizures using a generative spatio-temporal model. We assume that there are some states under first-order Markovian model during seizures, and each spike is generated when the corresponding state is activated. We also assume that a few specific epileptic activities (or atoms) exist in each state which are linearly combined and form the spikes. Each epileptic activity is described by two characteristics: (1) its spatial topography which shows the organization of current sources and sinks generating the epileptic activity, and (2) its temporal representation which illustrates the activation function of the epileptic activity. We show that the estimation of the model parameters, i.e. states and their epileptic activities (atoms), is similar to solving a dictionary learning problem for sparse representation. Instead of using classical dictionary learning algorithms, a new approach, taking into account the Markovian nature of the model, is proposed for estimating the models parameters, and its efficiency is experimentally verified. MAIN RESULTS: Experimental results show that there are one dominant and one unstable state with two epileptic activities in each during the seizures (temporal analysis). It is also found that the top and bottom layers of the somatosensory cortex are the most active layers during seizures (spatial analysis). The structural model is similar for all rats with a spatial topography which is the same for all rats but a temporal activation which changes according to the rat. SIGNIFICANCE: The proposed framework can be applied on any database acquired from a small area of the brain, and can provide valuable spatio-temporal analysis for neuroscientists.

Patient satisfaction with testosterone supplementation for the treatment of erectile dysfunction.

The long-term efficacy of testosterone supplementation for erectile dysfunction was evaluated using standardized questionnaires and differences between testosterone delivery systems analyzed. Forty-four patients receiving parenteral depo-testosterone, Testoderm scrotal patches, or Testoderm-TTS nonscrotal patches were evaluated with the Erectile Dysfunction Inventory of Treatment Satisfaction and International Index of Erectile Function questionnaires. Global questions regarding libido, energy, and improved erections demonstrated a significantly better response with depo-testosterone and Testoderm-TTS nonscrotal patches as compared to Testoderm scrotal patches. Testoderm-TTS nonscrotal patches and depo-testosterone resulted in significantly higher overall treatment satisfaction (p <.001), confidence in ability to engage in sexual activity (p <.001), and total Erectile Dysfunction Inventory of Treatment Satisfaction and International Index of Erectile Function scores (p <.001). Testoderm-TTS nonscrotal patches were significantly better than depo-testosterone with regard to satisfaction with sexual intercourse (International Index of Erectile Function question 5, p <.05). Testosterone replacement improved the quality of erections and level of libido in patients with erectile dysfunction. Treatment delivery systems appear to impact the success of therapy.

Holmium laser lithotripsy of a complicated biliary calculus.

More than 500,000 cholecystectomies are performed annually. Extracorporeal shockwave lithotripsy and endoscopic laser lithotripsy have been used for the management of common bile duct calculi, which complicate 10% of cases. We report the first successful clinical application of the Ho:YAG laser to a complex biliary calculus case.

Prostate-specific antigen (PSA) is an insulin-like growth factor binding protein-3 protease found in seminal plasma.

Insulin-like growth factor binding protein-3 (IGFBP-3), the major serum carrier protein for the IGFs, is absent from Western ligand blots of seminal plasma, but is detectable by RIA. IGFBP-3 protease activity has recently been described in pregnancy serum. We investigated the possibility that seminal plasma contains an IGFBP-3 protease, by incubating seminal plasma with 125I-labeled human IGFBP-3. Seminal plasma was found to have potent IGFBP-3 protease activity with a cleavage pattern different from that of pregnancy serum. Prostate-specific antigen (PSA) is a serine protease found in semen. Autoradiographs measuring IGFBP-3 protease activity demonstrated that purified PSA cleaved IGFBP-3, yielding a cleavage pattern identical to that of seminal plasma. IGFBP-2 and -4 in seminal plasma were not degraded by PSA. Cleavage of IGFBP-3 by PSA resulted in a marked reduction in the binding affinity of the fragments to IGF-I, but not IGF-II. We speculate that PSA may serve to modulate IGF function within the reproductive system or in prostate cancer by altering IGF-IGFBP-3 interactions.

Synthetic substrates and inhibitors for serine proteases from lymphocytes, mast cells, semen, and blood.

The substrate specificity of several serine proteases from cytotoxic T lymphocytes, natural killer cells, mast cells, seminal fluid, and blood plasma has been determined with synthetic peptide thiobenzyl ester and p-nitroanilide substrates. Several new enzymatic activities have been discovered. A variety of inhibitors such as isocoumarins, trifluoromethyl ketones, and peptide chloromethyl ketones were used to study these enzymes and were found to be potent inhibitors.

Identity of prostate specific antigen and the semen protein P30 purified by a rapid chromatography technique.

Previous investigators have reported the identity of prostate specific antigen (PSA) and the semen protein p30, but data to support these claims have not been published. We report here the rapid and continuous purification of PSA using a simple two column chromatography technique originally developed for purification of p30. Using commercial antisera to PSA and original antisera to p30 for detection, we show that the two glycoproteins have identical purification profiles by this technique which uses cation exchange chromatography and sizing chromatography. The antigens also have identical molecular weights by gel electrophoresis and gel filtration. Furthermore, both antigens correspond to the same prominent protein band in seminal plasma by sodium dodecylsulfate polyacrylamide gel electrophoresis. On commercial immunoassay for PSA, purified p30 gives a calibration curve identical to the commercial PSA kit calibrator (Pros-checkTM PSA Radioimmunoassay, Yang Laboratories). We conclude that PSA and the semen protein p30 are identical and can be easily purified by a rapid continuous technique.