Mercury in a marine trophic chain.
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Animals↗
Biomedical subjects
F Gonzalez
Publications and source records attributed to F Gonzalez.
Comparison of UW and Celsior solutions in experimental liver preservation by assessment of alpha-glutathione sulfotransferase.
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Adenosine↗
Large scale transgenic and cluster deletion analysis of the HoxD complex separate an ancestral regulatory module from evolutionary innovations.
The ancestral role of the Hox gene family is specifying morphogenetic differences along the main body axis. In vertebrates, HoxD genes were also co-opted along with the emergence of novel structures such as limbs and genitalia. We propose that these functional recruitments relied on the appearance, or implementation, of regulatory sequences outside of the complex. Whereas transgenic human and murine HOXD clusters could function during axial patterning, in mice they were not expressed outside the trunk. Accordingly, deletion of the entire cluster abolished axial expression, whereas recently acquired regulatory controls were preserved.
Animals↗
The Gal4 activation domain binds Sug2 protein, a proteasome component, in vivo and in vitro.
An in vivo protein interaction assay was used to search a yeast cDNA library for proteins that bind to the acidic activation domain (AD) of the yeast Gal4 protein. Sug2 protein, a component of the 19 S regulatory particle of the 26 S proteasome, was one of seven proteins identified in this screen. In vitro binding assays confirm a direct interaction between these proteins. SUG2 and SUG1, another 19 S component, were originally discovered as a mutation able to suppress the phenotype of a Gal4 truncation mutant (Gal4(D)p) lacking much of its AD. Sug1p has previously been shown to bind the Gal4 AD in vitro. Taken together, these genetic and biochemical data suggest a biologically significant interaction between the Gal4 protein and the 19 S regulatory particle of the proteasome. Indeed, it is demonstrated here that the Gal4 AD interacts specifically with immunopurified 19 S complex. The proteasome regulatory particle has been shown recently to play a direct role in RNA polymerase II transcription and the activator-19 S interaction could be important in recruiting this large complex to transcriptionally active GAL genes.
Adenosine Triphosphatases↗
Response latencies to visual stimulation and disparity sensitivity in single cells of the awake Macaca mulatta visual cortex.
The onset response latencies to dynamic random dot figures (solid figures) and dynamic random dot stereograms were measured in single units recorded from areas V1 and V2 of two awake Macaca mulatta monkeys. We studied 56 cells, 39 from V1 and 17 from V2. In 14 disparity sensitive and 13 disparity unsensitive cells from V1 the median latencies to solid figures were 59.8 and 73.6 ms, respectively, which were statistically different. In 26 disparity sensitive cells from V1 and 17 from V2 the median latencies to stereofigures were 85.6 and 97.9 ms, respectively, which were statistically different. These results indicate that V1 disparity sensitive cells may have shorter integration time than disparity unsensitive cells and that there is a transferring delay for disparity information between areas V1 and V2.
Action Potentials↗
Catecholamine levels in practitioners of the transcendental meditation technique.
With the aim of evaluating the sympathetic-adrenal medulla system in subjects practicing transcendental meditation (TM), their plasma catecholamine levels were determined at two different times of day. The study group consisted of 19 subjects who regularly practice either TM or Sidhi-TM technique, with a control group made up of 16 healthy subjects who had not previously used any relaxation technique. Catecholamine plasma levels were determined by high performance liquid chromatography, at 0900 and 2000 h. Morning and evening norepinephrine (NE) levels and morning epinephrine (E) levels were significantly lower in the TM group than in the control subjects (morning NE levels, pg/ml, mean+/-S.E.: TM group 136.6+/-13.0, control 236.8+/-21.0, P=.0001; evening NE levels: TM group 119.7+/-10.8, control 175.6+/-17.4, P=.009; morning E levels, pg/ml: TM group 140.2+/-10.6, control 196.7+/-23.8, P=.019). No differences were recorded for evening E levels and dopamine (DA) levels. No significant differences were found for catecholamine levels measured at different times of day in the TM group, demonstrating a lack of daily hormonal rhythm. Anxiety levels were similar in both groups. Based on the results obtained, it can be considered that the regular practice of TM has a significant effect on the sympathetic-adrenal medulla system. A low hormonal response to daily stress caused by sympathetic tone regulation through regular TM could explain our results, as well as the physiological and other effects related to the field of health described in those who practice meditation.
Adolescent↗
Selective chemical inactivation of AAA proteins reveals distinct functions of proteasomal ATPases.
BACKGROUND: The 26S proteasome contains six highly related ATPases of the AAA family. We have developed a strategy that allows selective inhibition of individual proteasomal ATPases in the intact proteasome. Mutation of a threonine in the active site of Sug1/Rpt6 or Sug2/Rpt4 to a cysteine sensitizes these proteins to inactivation through alkylation by the sulfhydryl modifying agent NEM. Using this technique the individual contributions of Sug1 and Sug2 to proteasome function can be assessed. RESULTS: We show that both Sug1 and Sug2 can be selectively alkylated by NEM in the context of the intact 26S complex and as predicted by structural modeling, this inactivates the ATPase function. Using this technique we demonstrate that both Sug 1 and 2 are required for full peptidase activity of the proteasome and that their functions are not redundant. Kinetic analysis suggests that Sug2 may have an important role in maintaining the interaction between the 19S regulatory complex and the 20S proteasome. In contrast, inhibition of Sug1 apparently decreases peptidase activity of the 26S proteasome by another mechanism. CONCLUSIONS: These results describe a useful technique for the selective inactivation of AAA proteins. In addition, they also demonstrate that the functions of two related proteasomal AAA proteins are not redundant, suggesting differential roles of proteasomal AAA proteins in protein degradation.
Adenosine Triphosphatases↗
The 19S regulatory particle of the proteasome is required for efficient transcription elongation by RNA polymerase II.
It is generally thought that the primary or even sole activity of the 19S regulatory particle of the 26S proteasome is to facilitate the degradation of polyubiquitinated proteins by the 20S-core subunit. However, we present evidence that the 19S complex is required for efficient elongation of RNA polymerase II (RNAP II) in vitro and in vivo. First, yeast strains carrying alleles of SUG1 and SUG2, encoding 19S components, exhibit phenotypes indicative of elongation defects. Second, in vitro transcription is inhibited by antibodies raised against Sug1, or by heat-inactivating temperature-sensitive Sug1 mutants with restoration of elongation by addition of immunopurified 19S complex. Finally, Cdc68, a known elongation factor, coimmunoprecipitates with the 19S complex, indicating a physical interaction. Inhibition of the 20S proteolytic core of the proteasome has no effect on elongation. This work defines a nonproteolytic role for the 19S complex in RNAP II transcription.
Adenosine Triphosphatases↗
Comparative analysis of outcome and clinical features in children with pleural empyema caused by penicillin-nonsusceptible and penicillin-susceptible Streptococcus pneumoniae.
OBJECTIVE: To describe the clinical characteristics of pleural empyema in children caused by Streptococcus pneumoniae nonsusceptible to penicillin and compare their clinical outcome with pleural empyemas caused by penicillin-susceptible organisms. METHODS: Records of 109 children with complicated pleural effusions between January 1996 and December 1998 were retrospectively reviewed. RESULTS: Pathogens were recovered in 45 of these cases. Streptococcus pneumoniae represented 71% of the isolates, with 20 (62%) and 12 (38%) of the strains proving susceptible and nonsusceptible to penicillin, respectively. The average age for children with penicillin-nonsusceptible infections was 18.3 months compared with an average age of 40.9 months for those with penicillin-susceptible infections (P = 0.03). Previous antibiotic treatment was more frequent in children with penicillin-nonsusceptible organisms (P = 0.05). No significant differences were found between the two groups for gender, underlying diseases, duration of fever and tachypnea, need of surgical treatment, bacteremia incidence, mean duration of therapy, or length of hospital stay. CONCLUSIONS: Pleural empyemas caused by penicillin-nonsusceptible S. pneumoniae appear to be associated with younger age and previous antibiotic treatment. By contrast, the outcome was not influenced by the penicillin susceptibility of the pneumococcus strains.
Bacteremia↗
Diode laser photocoagulation of choroidal neovascularization associated with retinal pigment epithelial detachment.
AIMS/BACKGROUND: Association of choroidal neovascularization with pigment epithelial detachment is not an uncommon feature. Since this condition usually has a poor visual outcome, new treatments should be developed. METHODS: We studied the anatomical and visual results of 11 eyes with this association as a manifestation of an Exudative Age Related Macular Degeneration which were treated with diode laser photocoagulation guided by indocyanine green angiography. The average follow up time was 25.5 months (from 12 to 48 months). RESULTS: Complete closure with complete resolution of the exudates and flattening of the detachment was observed in five eyes (45%). Visual acuity in the final examination improved or remained stable in 6 cases (55%). CONCLUSION: These results indicate that diode laser photocoagulation guided by indocyanine green angiography is at least as effective as conventional lasers with shorter wavelengths for treatment of vascularized pigment epithelial detachments in Age Related Macular Degeneration.
Aged↗
Receptive field organization of disparity-sensitive cells in Macaque medial superior temporal cortex.
Binocular disparities are crucial for building an accurate three-dimensional representation of the peripersonal environment in a viewer-centred frame of reference. Previous studies have shown that visual cells of the medial superior temporal cortex (MST) have large receptive fields and that they are sensitive to disparities present in large surfaces. By using a reverse cross-correlation technique in this study we tested 175 disparity-sensitive units recorded from MST in the awake Macaca mulatta monkey to determine if these large receptive fields are homogeneous in terms of disparity sensitivity. We found that the receptive fields of 50 cells (50 out of 175, 29%) showed subregions with specific disparity sensitivity. These subregions presented eccentricities from 0.8 to 22.3 degrees and their sizes varied from 1.6 to 15.3 degrees 2. This particular receptive field organization represents a suitable mechanism for encoding the location of small objects within our peripersonal space.
Action Potentials↗
Binocular interaction and sensitivity to horizontal disparity in visual cortex in the awake monkey.
We evaluated the binocular interaction and horizontal disparity sensitivity in neurons recorded from macaque visual cortex. Neurons from V1 of three awake Macaca mulatta monkeys were isolated by means of extracellular recording and tested for disparity sensitivity with dynamic random dot stereograms. Neurons sensitive to horizontal disparities were stimulated both monocularly and binocularly with flashing bars and their responses quantified. ANOVA and regression tests were used for data analysis. Sixty-six cells out of 185 (66/185, 36%) showed sensitivity to horizontal disparity. Disparity sensitive cells were grouped into near (25/66, 38%), tuned inhibitory (16/66, 24%), far (13/66, 20%) and tuned excitatory (12/66, 18%). Receptive fields of tuned cells were located more centrally in the visual field than those of near and far cells. The binocular interaction in tuned inhibitory cells increased linearly along with ocular unbalance. Most of tuned excitatory cells (10/12, 83%) showed facilitatory binocular interaction, characterized by a stronger response to binocular stimulation than to the stimulation of the dominant eye. On the contrary, most of tuned inhibitory cells (14/16, 88%) showed suppressory binocular interaction, characterized by a weaker response to binocular stimulation than to the stimulation of the dominant eye. Near and far cells showed both types of interaction in similar percentages. The binocular response showed a linear relationship with the sum of both monocular responses in tuned excitatory, tuned inhibitory and near cells, but not in far cells. Sensitivity to horizontal disparity may be a result of facilitatory and suppressive interactions between left and right inputs.
Animals↗
Black widow bites in children.
While seldom lethal, the bite of the black widow spider causes serious systemic symptoms that appear suddenly and progress rapidly. Children are more vulnerable to these complications; therefore, early hospitalization and aggressive therapy must be considered. General information about the widow spider genus is presented, and an illustrative case and treatment options are discussed.
Animals↗
[ [In Process Citation]
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Journal Article↗
Differences that matter: major cytotoxic T cell-stimulating minor histocompatibility antigens.
Despite thousands of genetic polymorphisms among MHC matched mouse strains, a few unknown histocompatibility antigens are targeted by the cytotoxic T cells specific for tissue grafts. We isolated the cDNA of a novel BALB.B antigen gene that defines the polymorphic H28 locus on chromosome 3 and yields the naturally processed ILENFPRL (IFL8) peptide for presentation by Kb MHC to C57BI/6 CTL. The CTL specific for the IFL8/Kb and our previously identified H60/Kb complexes represent a major fraction of the B6 anti-BALB.B immune response. The immunodominance of these antigens can be explained by their differential transcription in the donor versus the host strains and their expression in professional donor antigen-presenting cells.
Amino Acid Sequence↗
19. Correlation between FDG PET data and EEG dipole modeling.
Purpose: FDG-PET images and EEG dipole modelling were used to localization of interictal epileptogenic foci. A multimodality approach with the analysis of FDG-PET images, EEG dipoles and anatomical images (MRI) were applied to patients with drug-resistant epilepsy.Methods: Source location was determined using Brain Electromagnetic Source Analysis (BESA) program. The dipole location provided by BESA was then transformed into PET co-ordinates using the patient's MRI previously registered with the PET image. As a difference with other methods, no external markers are necessary.Results: The study group includes ten drug-resistant epileptic patients. FDG hypometabolism was found in all patients. Abnormalities in glucose uptake were always ipsilateral to the EEG dipole. However, quantitative analysis of FDG-PET within hypometabolic areas showed no significant correlation between decrease glucose uptake and location of EEG-dipole source. The comparison of the results using both methods shows that the dipole location matches the FDG-PET hypometabolic area for all the patients. Combining the spatial localization on FDG-PET with the temporal accuracy of EEG dipole source aids in the exact localization of the epileptogenic focus.Conclusion: As a conclusion, the results show that projection of EEG dipole data onto FDG-PET may play a key role in the indication of surgery for the treatment of drug-resistant epileptic patients, provided it is simple and easy to perform.
Journal Article↗
Tuberculous meningitis in children: clinical features and outcome in 40 cases.
In order to assess the epidemiology, clinical features and outcome of tuberculous meningitis, a retrospective review of patients was conducted between January 1989 and December 1995. Forty cases (representing 10%, of all paediatric patients with tuberculosis) were included. Mean age was 46 months (range 1-165 months). Eighteen (45%) children were classified as stage I (non-specific febrile illness without neurological signs), 16 (40%) as stage II (neurological signs without marked changes in sensorium) and 6 (15%) as stage III (major neurological signs with sensorial changes and/or coma). Twenty-seven (67%) patients had received BCG vaccination and 14 (35%) displayed an induration zone higher than 10 mm after a 2-TU PPD test. Mycobacterium tuberculosis was recovered from 24 (61%) patients. Hydrocephalus was demonstrated by cranial computed tomography in 31 (78%) children. Overall, 18 (45%) children had a full recovery. Mild, moderate and severe neurological sequelae were shown by 7 (18%), 3 (8%) and 9 (22%) of the patients, respectively. Three fatal cases (7%) were observed. The presence of seizures (RR 15.6, 2.02-119.1) and absence of extrameningeal foci (RR 4.95, 1.10-22.1) were identified as risk factors by multivariate analysis. These findings emphasize the need quickly to diagnose tuberculosis in children in order to give appropriate and early treatment.
Adolescent↗
Bedside placement of transpyloric feeding tubes in the pediatric intensive care unit using gastric insufflation.
OBJECTIVE: To test the effectiveness of gastric insufflation as an adjunct to placement of feeding tubes in the small bowel. DESIGN: Prospective, randomized, controlled study. SETTING: Pediatric intensive care unit in a tertiary children's hospital. PATIENTS: A total of 50 children requiring enteral nutrition via a nasoenteral feeding tube in the small bowel. INTERVENTIONS: An unweighted nasoenteral feeding tube attached to a three-way stopcock and a 60 mL syringe was inserted through the nares into the stomach. After 10 mL/kg of air was injected, the tube was advanced a distance estimated to position the tip of the tube proximal to the pylorus. An additional 10 mL/kg of air was then injected, and the tube was advanced a distance needed to place the tube in the fourth part of the duodenum. In the control group, feeding tubes were inserted through the nares and into the stomach. The tube was then advanced a distance estimated to place the tube in the fourth part of the duodenum. No air was injected in the control group. MEASUREMENTS AND MAIN RESULTS: When gastric insufflation was used, 23 of 25 feeding tubes were successfully placed in the small bowel on the first attempt compared with 11 of 25 in the control group (p = .001). All feeding tubes were successfully placed after two attempts in the gastric insufflation group compared with 18 of 25 in the control group (p < .001). The time between the first attempt at placement of a transpyloric feeding tube and the initiation of feeding was significantly shorter in the study group than in the control group. There were no complications in either group. CONCLUSION: Gastric insufflation allows rapid placement of feeding tubes into the small bowel with fewer attempts compared with a standard insertion technique in children.
Child, Preschool↗