Novel non-cytotoxic, bioactive and biodegradable hybrid materials based on polyurethanes/TiO2 for biomedical applications.

Titanium compounds have demonstrated great interfacial properties with biological tissues whereas a wide variety of polyurethanes have also been successfully probed in medical applications. However, studies about hybrids based on polyurethanes/TiO2 for medical applications are scarce. The aim of this work is to design novel biodegradable hybrid materials based on polyurethanes/TiO2 (80% organic-20% inorganic) and to perform a preliminary study of the potential applications in bone regeneration. The hybrids have been prepared by a sol-gel reaction using titanium isopropoxide as precursor of the inorganic component and polyurethane as the organic one. A series of polyurethanes has been prepared using different polyesters glycol succinate as soft segment, and 1,6-diisocyanatohexane (HDI) and butanediol (BD) as linear hard segment. The spectroscopy techniques used allow to confirm the formation of the required polyurethanes by the identification of bands related to carboxylic groups (COOH), and the amine groups (NH), and also the TiOH bonds and the bonds related to the interconnected network between the inorganic and the organic components from hybrids. The results from SEM/EDS show a homogeneous distribution of the inorganic component into the organic matrix. The nontoxic character of the hybrid (H400) was probed using MG-63 cell line with over 90% of cell viability. Finally, the formation of a hydroxyapatite layer in the material surface after 21days of soaking in SBF shows the bioactive character.

Study of Different Involutive Changes in Bone Mineral Density Measured in Ward's Triangle and Trabecular Volume Measured in Iliac Crest in Relation to Age.

BACKGROUND: The ageing process causes changes in the bone structure, in bone mineral density, and musculoskeletal disorders. AIMS: The purpose of this study is to evaluate and compare involutive changes in bone structure that occur in relation to age in men and women through the study of bone mineral density at the Ward's triangle and trabecular volume. SUBJECTS AND METHODS: In this study, we analysed bone mineral density at Ward's triangle in 70 people (38 men and 32 women) and did a histomorphometric study of trabecular volume at the right iliac crest in 66 samples (42 males and 24 females) obtained from autopsies of court cases, aged between 13 and 83 years. RESULTS: The results show significant correlations between measurements of bone mineral density, trabecular volume values and anthropometric measures of age, gender and body mass index. CONCLUSIONS: This study shows involutional changes that occur in the bone mineral density and Ward's triangle in the bone structure during the process of ageing. In addition, both weight and height have a great influence on bone mineral density and changes in bone that occur; and body mass index is a very important determinant of bone mineral density.

The neutron imaging diagnostic at NIF (invited).

A neutron imaging diagnostic has recently been commissioned at the National Ignition Facility (NIF). This new system is an important diagnostic tool for inertial fusion studies at the NIF for measuring the size and shape of the burning DT plasma during the ignition stage of Inertial Confinement Fusion (ICF) implosions. The imaging technique utilizes a pinhole neutron aperture, placed between the neutron source and a neutron detector. The detection system measures the two dimensional distribution of neutrons passing through the pinhole. This diagnostic has been designed to collect two images at two times. The long flight path for this diagnostic, 28 m, results in a chromatic separation of the neutrons, allowing the independently timed images to measure the source distribution for two neutron energies. Typically the first image measures the distribution of the 14 MeV neutrons and the second image of the 6-12 MeV neutrons. The combination of these two images has provided data on the size and shape of the burning plasma within the compressed capsule, as well as a measure of the quantity and spatial distribution of the cold fuel surrounding this core.

PCO2 and room air saturation values in premature infants at risk for bronchopulmonary dysplasia.

OBJECTIVE: To determine the capillary partial pressure of carbon dioxide (PCO(2)) and room air transcutaneous hemoglobin saturation (RA SAT) at 36 weeks' postmenstrual age (PMA) in infants born with weight between 501 and 1250 g. STUDY DESIGN: Multicenter, prospective investigation with primary data collection within 72 h of 36 weeks PMA or discharge, whichever first. PCO(2) and RA SAT determinations were done at rest on infants not requiring mechanical ventilation or nasal continuous positive airway pressure (NCPAP). RESULT: A total of 220 infants were enrolled (mean gestational age 27.7 weeks, mean birthweight 951 g). In infants with traditionally defined chronic lung disease (CLD) compared to those without CLD, the mean PCO(2) was significantly higher (54 versus 45 mm Hg) and the median RA SAT significantly lower (<80 versus 97%). In infants with the new classification of bronchopulmonary dysplasia (BPD), there was a significant linear trend toward increasing PCO(2) with increasing severity of BPD (45, 47, 54 and 62 mm Hg in No, Mild, Moderate and Severe BPD). There was a significant linear trend toward decreasing RA SAT with increasing severity of BPD (97, 95 <80, <80% in No, Mild, Moderate and Severe BPD). CONCLUSION: Defining CLD as BPD based upon a RA SAT test is a more discriminate, objective method to categorize lung injury. PCO(2) is an objective measure of lung function that inversely correlates with RA SAT. These determinations done together at 36 weeks PMA may provide more precise and accurate estimates of lung injury that might allow for better understanding of pulmonary therapies and clearer comparison of BPD rates and severities among NICUs.

Meningitis por Listeria como complicación del tratamiento con infliximab en paciente con enfermedad de Crohn / Listeria meningitis as complication of treatment with infliximab in a patient with Crohn's disease

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Adaptive responses of gamma-aminobutyric acid neurons in the ventral tegmental area to chronic ethanol.

We have recently identified a homogeneous population of gamma-aminobutyric acid (GABA)-containing neurons in the ventral tegmental area (VTA), an area implicated in the reinforcing properties of alcohol. We evaluated the effects of local and systemic ethanol on VTA GABA neuron spontaneous activity in ethanol naive and chronically treated freely behaving rats and in anesthetized rats. In freely behaving animals, acute i.p. administration of 0.2 to 2.0 g/kg ethanol reduced the firing rate of VTA GABA neurons. Chronic administration of 2.0 g/kg i.p. ethanol enhanced baseline activity of VTA GABA neurons and induced tolerance to ethanol inhibition of their firing rate. In a separate group of freely behaving animals, tolerance to 0.4 to 2.0 g/kg i.p. ethanol-induced inhibition of VTA GABA neuron firing rate was observed following 2 weeks of chronic exposure to ethanol vapors producing intermittent blood alcohol levels of 158 mg/100 ml. In acute studies in halothane-anesthetized animals, ethanol applied locally into the VTA decreased the spontaneous firing rate of VTA GABA neurons, whereas systemic ethanol produced an early inhibition followed by a late excitation at 30 to 60 min after the ethanol injection, suggesting that ethanol modulation of an extrinsic input may excite VTA GABA neurons. Tolerance to local ethanol inhibition of VTA GABA neuron firing rate was produced by 2 weeks of chronic exposure to intermittent ethanol vapors. These results demonstrate the marked sensitivity of these neurons to ethanol and suggest that chronic ethanol administration produces selective adaptive circuit responses within the VTA or in extrategmental structures that regulate VTA GABA neuron activity.

[Prevalence of the 185Ag deletion of the BRCA1 gene in Chilean women with breast neoplasm]. / Prevalencia de la deleción 185AG del gen BRCA1 en mujeres chilenas con cáncer de mama.

BACKGROUND: The most important identified pathogenic factor for breast cancer is the presence of mutations in BRCA1 gene. These are associated with familial breast cancer in up to 80% of cases. The most frequent mutation of BRCA1 gene in Caucasian populations is the exon 2 185AG deletion. AIM: To study the presence of 185AG deletion in Chilean women with sporadic or familial breast cancer. PATIENTS AND METHODS: We studied 15 women with familial breast cancer, in whom at least one close relative was affected, and 40 women with sporadic breast cancer. In genomic DNA obtained from a blood sample, an allele specific polymerase chain reaction was done. This reaction allows the identification of 185AG deletion and uses two pairs of primers. One for the native form that renders a 118 base pairs product and one for the deletion that renders a 170 base pairs product, both with a respective 280 base pairs internal control. RESULTS: The diagnosis of breast cancer was done at 40 +/- 5 and 65 +/- 10 years old in women with familial and sporadic breast cancer, respectively. In none of the samples, the amplification of the 170 base pairs band that corresponds to 185AG deletion, was obtained. In both groups, the product of the amplification was the 118 base pairs band, that corresponds to the native form of BRCA1 gene. The polymerase chain reaction was optimized for a duration of 90 minutes. CONCLUSIONS: 185AG deletion of BRCA1 gene was not detected in this group of Chilean women with sporadic or familial breast cancer.

Transient and persistent consequences of acute stress on long-term potentiation (LTP), synaptic efficacy, theta rhythms and bursts in area CA1 of the hippocampus.

Previous studies reported that exposure to an acute stressor of restraint and intermittent tailshock impairs long-term potentiation (LTP) in area CA1 of the rat hippocampus. In the first experiment, the longevity of the stress-induced impairment of LTP was determined. LTP of the excitatory postsynaptic potential (EPSP) was impaired 2 but not 4 days after stressor cessation. Exposure to the stressor also persistently enhanced the synaptic response to the tetanic stimulation patterned after theta rhythm activity (10, 100 Hz bursts delivered at 5 Hz). In a second experiment, we tested the hypothesis that exposure to the stressor enhanced synaptic efficacy itself. EPSPs were recorded from freely moving rats before, during and after stressor exposure. The synaptic response was not enhanced during stressor exposure. Instead, cessation of the stressor (and perhaps movement associated with release from restraint) induced a transient (< 2 min) decrease in synaptic efficacy. To determine whether exposure to the stressor enhances endogenous theta rhythms in area CA1, electroencephalographic (EEG) recordings were obtained from freely moving rats before, during and after exposure to the stressor. The power of theta (4-8 Hz) and low frequency (0.1-3.9 Hz) activity was enhanced in response to the tailshock aspect of the stressor. Together, the results indicate that exposure to an acute stressful event increases theta activity and its cessation transiently decreases synaptic efficacy. These transient effects are succeeded by a persistently sensitized response to theta burst stimulation and impaired LTP.

WAY-100635, a potent and selective 5-hydroxytryptamine1A antagonist, increases serotonergic neuronal activity in behaving cats: comparison with (S)-WAY-100135.

We reported previously that pharmacological blockade of somatodendritic 5-hydroxytryptamine (5-HT)1A autoreceptors with spiperone, a nonselective 5-HT1A antagonist, increases the spontaneous firing rate of central serotonergic neurons in awake cats. The present study examined the effects of systemic administration of two reportedly selective 5-HT1A receptor antagonists, (S)-WAY-100135 {N-tert-butyl-3-[4-(2-methoxyphenyl) piperazin-1-yl]-2-phenylpropanamide} and its more potent analog WAY-100635 {N-[2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide}, on the single-unit activity of serotonergic neurons in the dorsal raphe nucleus of freely moving cats. In addition, we assessed the antagonist action of these compounds at the 5-HT1A autoreceptor by examining their ability to block the inhibition of serotonergic neuronal activity produced by systemic administration of 8-hydroxy-2-(di-n-propylamino)tetralin, a highly selective 5-HT1A agonist. Administration of (S)-WAY-100135 (0.025-1.0 mg/kg i.v.) moderately depressed neuronal activity at all doses tested. In contrast, administration of WAY-100635 (0.025-0.5 mg/kg i.v.) significantly increased neuronal activity. The stimulatory action of WAY-100635, like that of spiperone, was evident during wakefulness (when serotonergic neurons typically display a relatively high level of activity) but not during sleep (when serotonergic neurons display little or no spontaneous activity). Pretreatment with (S)-WAY-100135 (0.5 mg/kg i.v.) weakly attenuated the inhibitory action of 8-hydroxy-2-(di-n-propylamino)tetralin. In contrast, WAY-100635 at doses as low as 0.1 mg/kg i.v. completely blocked the action of 8-hydroxy-2-(di-n-propylamino)tetralin. The antagonist action of WAY-100635 at 5-HT1A autoreceptors closely paralleled its ability to increase neuronal activity. Overall, WAY-100635 appears to act as a selective 5-HT1A antagonist, whereas (S)-WAY-100135 does not. The results obtained with WAY-100635 confirm our previous findings obtained with spiperone and further support the hypothesis that 5-HT1A autoreceptor-mediated feedback inhibition operates under physiological conditions.

Effects of neonatal ethanol exposure on saccharin consumption.

Prenatal ethanol exposure has been associated with alterations in a variety of sexually dimorphic behaviors in rats. This study examined the effects of neonatal ethanol exposure on saccharin consumption, a sexually dimorphic behavior in rats. Subjects were Sprague-Dawley rats that were artificially reared (AR) from postnatal day (PN) 4-PN12 through gastrostomy tubes with ethanol exposure limited to PN4-PN10. The AR groups included two ethanol doses (6 g/kg/day and 4 g/kg/day) and an isocaloric maltose-dextrin control. A sham surgery control group was also included. The AR subjects were returned to their dams on PN13. At 21 days of age, subjects were housed with one same-sex sibling and free access to rat chow and water until testing. Subjects were tested for saccharin preference and consumption at 110 days of age. Typically, male rats consume less saccharin than females, and this was evident in the 4 g/kg ethanol group and both control groups. However, this was not apparent among the 6 g/kg ethanol-exposed males. Furthermore, saccharin preference seemed to be reduced in the females exposed to 6 g/kg ethanol. These data suggest that the "sensitive period" for ethanol's effects on sex differences in saccharin consumption extends into postnatal life.

Rabies veterinary virus vaccine produced in BHK-21 cells grown on microcarriers in a bioreactor.

BHK-21 cells were grown in microcarriers in the CELLIGEN CL 50 bioreactor to produce a stock of rabies veterinary virus vaccine PV (Pasteur virus) strain. Perfusion mode operation of this bioreactor produced between two- and fourfold larger yields (cells/ml) than traditional stationary cell culture systems (i.e., Blake, and Roller bottles or cell factory multitrays). The method employed harvested 281 of rabies virus in 200 h (infectivity titer 0.6 +/- 1.4 x 10(7) LD50 per ml) in a single operation. The risk of contamination is thus reduced when compared with traditional stationary methods which, in order to obtain the same amount of virus, would require the operation of 285 Blake bottles, or 143 Roller bottles, or 15 Cell Factory multitrays (10 trays). By perfusion mode operation of the bioreactor, 89% of the cell culture medium was recovered as vaccinal virus, which contrasts with the yield of only 50-59% using traditional cell culture systems. On the other hand, only 925 ml of fetal serum was required to obtain the 281 of rabies virus harvest as compared to the 3420 ml required by traditional methods.

Prostatotomía transuretral estudio prospectivo / Transurethral prostatomy prospective study

Se presentan 20 pacientes con adenoma prostático sintomático tratados con prostatotomía transuretral. El 83% era bilobar obstructivo y el 90% tenía peso no superior a 30 grs. La técnica fue resección de un canal a las 7 desde cuello hasta vero. Los resultados fueron buenos en el 70%. Los 3 pacientes con mal resultado tenían lóbulo medio desarrollado