We have determined using NMR the structure of the complex between the third double-stranded RNA-binding domain (dsRBD3) of Drosophila Staufen protein and a RNA stem-loop with optimal binding properties in vitro. This work was designed to understand how dsRBD proteins bind RNA and to investigate the role of Staufen dsRBDs in the localization of maternal RNAs during early embryonic development. The structure determination was challenging, because of weak, nonsequence specific binding and residual conformational flexibility at the RNA-protein interface. In order to overcome the problems originated by the weak interaction, we used both new and more traditional approaches to obtain distance and orientation information for the protein and RNA components of the complex. The resulting structure allowed the verification of aspects of RNA recognition by dsRBDs matching the information obtained by a related crystallographic study. We were also able to generate new observations that are likely to be relevant to dsRBD-RNA binding and to the physiological role of Staufen protein.

Animals↗

PubMedDate not supplied

Benign nature of atrial dissociation in pediatric patients.

Atrial dissociation is defined electrocardiographically by the presence of an ectopic atrial rhythm depolarizing independently of the basic sinus rhythm, and is characterized by entrance and exit block. Atrial dissociation is most often observed as an ominous sign in adults with severe myocardial dysfunction. We have observed atrial dissociation in 3 pediatric patients, aged 5 to 22 years, who were essentially asymptomatic from this arrhythmia. All 3 patients are well, without therapy for atrial dissociation, during a follow-up period of 1 to 5 years. The benign nature of atrial dissociation in the pediatric patient as compared with the adult is stressed.

Adolescent↗

PubMedDate not supplied

Single cell activity in chronic unit recording: a quantitative study of the unit amplitude spectrum.

The ratio of standard deviation to mean, of the amplitude spectrum of well resolved single units, is shown to scale exponentially. This scaling is explained on the basis of a consideration of the relationship of extracellular voltage to voltage gradient, in a dendritic neuron model. A method is then advanced to extract, from multi-unit data, normally distributed amplitude spectra which are indistinguishable from those of well resolved single units. This method is suggested as a means of characterizing, in general, the unit activity obtained from chronically implanted preparations.

Animals↗

PubMedDate not supplied

Evoked potential-unit relationships in behaving cats.

Adult cats were implanted with a movable microelectrode, and trained to respond differentially to two different frequencies of light flicker. Unit responses and evoked potentials were recorded along trajectories in the visual cortex and lateral geniculate nucleus. Although strong correlations are shown to exist between certain components of the evoked potential and peaks in the poststimulus histogram, it is demonstrated that it is impossible to specify a causal, predictive relationship.

Animals↗

PubMedDate not supplied

An examination of the participation of neurons in readout from memory.

Adult cats were implanted with a movable microelectrode and were trained to perform for food reward in response to diffuse light flicker at two different frequencies. After substantial overtraining, the patterns of cell response (poststimulus histogram) were obtained during generalization trials, using an intermediate frequency stimulus. An average of 29% of the cells examined in lateral geniculate nucleus and visual cortex traverses showed statistically significant differences in the late component of the neuronal response when different responses to the same generalization stimulus were compared.

Animals↗

PubMedDate not supplied

[Use of topical ciprofloxacin in chronic suppurating otitis media].

OBJECTIVE: A prospective study is presented. We carry out an analysis of the results obtained after treatment with different protocols of administration of ciprofloxacin, during the active phase in chronic otitis media and in chronic otorrhea. MATERIAL AND METHOD: A multicenter, prospective study is carried out, in 3 ENT departments, corresponding to 3 reference tertiary hospitals. 300 patients were included ranging from 5 to 73 years old, all were diagnosed of chronic disease of the middle ear: simple chronic otitis media (n = 128), chronic otitis with bone reabsorption (n = 57), cholesteatoma infection (n = 42) and postsurgery ear infection (n = 73). Patients were placed in 5 treatment groups: ciprofloxacin (oral administration) (only adults were included), topical ciprofloxacin (0.5%), topical ciprofloxacin (0.2%), topical ciprofloxacin (0.2%) plus oral ciprofloxacin and ciprofloxacin (0.3%) plus topical fluocinolone. There was a control group treated with polimixin plus neomicine and hidrocortison. RESULTS: The most common isolated bacterias were: Pseudomonas aeruginosa and S. aureus. We found 19 resistant strains to ciprofloxacin. A better therapeutic response was observed in the topical administration groups. In topical administration, a difference was only observed in the cholesteatoma and chronic middle ear infection with bone reabsorption groups, in those patients that were administered the ciprofloxacin with fluocinolone. CONCLUSION: Forms of topical treatment, with ciprofloxacin, in active infection of chronic disease of the middle ear, improve the results compared to oral administration. The association with of topical fluocinolone improves the results in the cases with cholesteatoma infection and chronic middle ear infection.

Administration, Topical↗

PubMedDate not supplied

Arachnoiditis ossificans. Diagnosis with helical computed tomography.

Arachnoiditis ossificans (AO) is a rare entity in which ossification of the leptomeninges occurs. This report illustrates a patient with AO of the cervical and dorsal spine, diagnosed by helical computed tomography with multiplanar reconstruction. It demonstrates the value of computed tomography in diagnosing calcified plaques and the utility of multiplanar reconstruction in giving an exact anatomic reference to neurosurgeon.

Aged↗

PubMedDate not supplied

A model of suture-induced urolithiasis with urographic control in the bladder of the rat.

The characteristics of a model of urolithiasis in the bladder of male Wistar rats were evaluated. Two techniques were compared: one knot of suture material through the bladder wall, or 15-throw knots inside the bladder. Rats were randomly assigned to one of six groups, according to the technique and suture material used (polyester, silk, or chromic catgut). An excretory urogram was performed at days 30, 60, and 90. At the moment of positive radiographic diagnosis, animals were sacrificed and stones were obtained. All rats were sacrificed at day 90 regardless of the x-ray results. Variables evaluated were average days to a positive urogram, average weight of all uroliths, and percentage of animals developing urolithiasis throughout the study. There were no statistical differences between groups for the average weight of stones, which ranged from 0.008 to 1.502 g for individual cases. All three materials were more lithogenic with the 15-throw knot inside technique. No significant differences were detected for lithogenesis criteria between suture materials. X-ray dispersion spectroscopy evidenced calcium phosphate composition of two stones from chromic catgut, and magnesium phosphate composition of two stones from chromic catgut, two from silk, and two from polyester. Neo-epithelization over the suture was confirmed microscopically in bladders with the one-throw technique. We conclude that (1) this is an effective model of urolithiasis, with predictability in time, composition, and amount of stone formation; (2) the presence of more suture material inside the bladder is more lithogenic; and (3) excretory urograms are highly sensitive and specific for the noninvasive diagnosis of bladder urolithiasis.

Animals↗

PubMedDate not supplied

A community-based approach to the promotion of breastfeeding in Mexico.

A comprehensive education strategy is presented that links training, community education, research, and mass-media efforts to enhance breastfeeding practices. Breastfeeding promotion models, an administrative system, and lessons learned during the project are described. The keys to effective breastfeeding promotion are shown to be accurate information; appropriate education, training, and follow-up; and a supportive administrative system.

Breast Feeding↗