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J Romero

Publications and source records attributed to J Romero.

At least 55 records · Page 3Linked to original sources
PubMed2001

Analysis of discrimination threshold on the tritan axis.

Discrimination thresholds on the tritan axis were obtained for an extensive group of 66 stimuli: in some of the stimuli, S-cone trolands were held constant by keeping the product of the S-cone excitation level and the luminance unchanged, while in others only the luminance was changed to establish various S-cone troland values. These thresholds depended clearly on the S-cone value of the stimuli, while they remained almost constant against the retinal illumination. Thus, we noted that the excitation of the L - 2M channel had practically no influence over the discrimination threshold on the tritan axis, although this independence of delta S from L - 2M was not so obvious when the S value was high. With our data, we performed different fits, and found that the fit including the terms S, (L - 2M) and (L + M) adapted better to our results.

Adult↗
PubMed2001

Colorimetric and spectroradiometric characteristics of narrow-field-of-view clear skylight in Granada, Spain.

As part of our ongoing research into the clear daytime sky's visible structure, we analyze over 1,500 skylight spectra measured during a seven-month period in Granada, Spain. We use spectral radiances measured within 3 degrees fields of view (FOV's) to define colorimetric characteristics along four sky meridians: the solar meridian and three meridians at azimuths of 45 degrees, 90 degrees, and 315 degrees relative to it. The resulting clear-sky chromaticities in 44 different view directions (1) are close to but do not coincide with the CIE daylight locus, (2) form V-shaped meridional chromaticity curves along it (as expected from theory), and (3) have correlated color temperatures (CCT's) ranging from 3,800 K to infinity K. We also routinely observe that sky color and luminance are asymmetric about the solar meridian, usually perceptibly so. A principal-components analysis shows that three vectors are required for accurate clear-sky colorimetry, whereas six are needed for spectral analyses.

Journal Article↗
PubMed2001

Color and spectral analysis of daylight in southern Europe.

We have analyzed the colorimetric and spectral characteristics of 2600 daylight spectra (global spectral irradiances on a horizontal surface) measured for all sky states during a 2-year period at Granada, Spain. We describe in detail the chromaticity coordinates, correlated color temperatures (CCT), luminous efficacies, and relative UV and IR contents of Granada daylight. The chromaticity coordinates of Granada daylight lie far above the CIE locus at high CCTs (>9,000 K), and a CCT of 5,700 K best typifies this daylight. Our principal-components analysis shows that Granada daylight spectra can be adequately represented by using six-dimensional linear models in the visible, whereas seven-dimensional models are required if we include the UV or near-IR. Yet on average only three-dimensional models are needed to reconstruct spectra that are colorimetrically indistinguishable from the original spectra.

Journal Article↗
PubMed2001

Enteroviral meningitis. Cost of illness and considerations for the economic evaluation of potential therapies.

With limited financial resources available, it is now becoming more acceptable to evaluate medical innovations in terms of incremental economic value. The purpose of this paper is to provide an overview of enteroviral meningitis and to summarise the economic literature to identify relevant costs and outcomes. Enteroviral meningitis is the most common cause of aseptic meningitis, and occurs in 4.5 to 30 per 100,000 population annually with a duration of illness lasting between 1 and 2 weeks after onset of initial symptoms. The major resource categories that contribute to the overall direct costs of management of enteroviral meningitis include physician visits, hospital admissions, emergency room visits, medications, procedures such as lumbar puncture and computed tomography scans, re-hospitalizations and follow-up physician visits. Indirect costs are incurred in terms of school or work days missed or restrictions in daily activities. The total direct costs of an episode of enteroviral meningitis range from $US450 for outpatients to $US5093 for inpatient management (1996 values). The total indirect costs of an episode of enteroviral meningitis are estimated to be equivalent to 5 to 7 activity-restricted days. Interventions that improve early diagnosis or decrease the duration and need for hospitalisation will significantly affect the cost of managing enteroviral meningitis. Additional prospective studies are needed to study the impact of interventions on the burden of enteroviral meningitis.

Enterovirus Infections↗
PubMed2001

Pteridium aquilinum (bracken fern) toxicity in cattle in the humid Chaco of Tarija, Bolivia.

We studied the toxicity caused by chronic ingestion of Pteridium aquilinum (bracken) in cattle in the humid Chaco of Tarija, Bolivia. Bovine enzootic haematuria (BEH) and Carcinoma of the esophagus (CE) affected the herds. Sick animals showed caquexia, anemia, leucopenia and urine that turned from pink to intense red color with the presence of blood clots. Cattle grazed in the humid forests of the mountains where P aquilinum represented more than 50% of the plants. P aquilinum var arachnoideum and P aquilinum var Caudatum were present. Toxic norsesquiterpene, ptaquiloside, was identified in both varieties. Carcinomas were in the urinary bladders and esophagus of 100% and 50% of the cattle, respectively. Control of the intoxication could be difficult due to geographic characteristics of this Bolivian region.

Animals↗
PubMed2001

[Disinfection treatment for lettuces (Lactuca sativa) and strawberries (Fragatia Chiloensis)].

The disinfection of vegetables and fruits is a treatment applied in order to reduce their natural contamination or processes to the product along the different steps of the food chain until its consumption. In the present work the effect of two disinfectants products was studied: grapefruit seed extract (400 ppm) for 10 min and peracetic acid (2000 ppm) for 1 min (action times assayed according to the manufacturer recommendations) and other additional times. The germicidal action was carried out against the natural contaminants of lettuces and strawberries, through the determination of the germicidal efficiency (%). Treated and untreated strawberries were also evaluated for flavor changes through a sensorial difference test, triangular test. None of the assayed products reached the 99.999% destruction of the natural contaminants according to the Chambers test. Peracetic acid was the most effective disinfectant, reaching the highest destruction percentages at a time lower than that for grapefruit seed extract. Sensory analysis showed no significant differences (p = .05) between strawberries with and without disinfection treatments, at the conditions suggested by the manufacturer.

Bacteria↗
PubMed2000

Intracytoplasmic sperm injection with cryopreserved testicular spermatozoa.

To assess if testicular sperm cryopreservation is a valid alternative to repetition of testicular sperm retrieval techniques, results of a cryopreservation technique in pills have been retrospectively analyzed. Enough motile spermatozoa for ICSI were obtained in 172 from 190 (90.5%) frozen-thawed testicular sperm samples. Overall, 249 couples underwent 390 ICSI cycles, 156 using fresh and 234 using cryopreserved testicular sperm. Mean two-pronuclear fertilization rates per cycle were not significantly different after ICSI with fresh (62.0%) or with cryopreserved (63.2%) spermatozoa. Mean embryo cleavage rate per cycle was higher in the fresh (90.6%) than in the cryopreserved (84.6%) group (P = 0.016). However, clinical pregnancy rates per cycle (28.2% with fresh vs 27.8% with cryopreserved), implantation rates (12.2% vs 13.1%) and ongoing pregnancy rates per cycle (22.4% vs 21.8%) were not significantly different. Cryopreservation of testicular spermatozoa is an effective technique that can be used both in obstructive and in non-obstructive azoospermia.

Adolescent↗
PubMed2000

Therapeutic decision tree for patients with sustained ventricular tachyarrhythmias or aborted cardiac arrest: a critical review of the Antiarrhythmics Versus Implantable Defibrillator trial and the Canadian Implantable Defibrillator Study.

Antiarrhythmic drugs, mainly amiodarone and sotalol, radiofrequency catheter ablation, and the implantable cardioverter defibrillator (ICD) are the 3 therapeutic options in patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Idiopathic VT, incessant VT, frequently recurring, hemodynamically stable VT, and VT based on bundle branch reentry, are candidates for radiofrequency catheter ablation. Patients with high-risk ventricular tachyarrhythmias should receive ICDs as initial therapy. Two studies, the Antiarrhythmics Versus Implantable Defibrillator trial (AVID) and the Canadian Implantable Defibrillator Study (CIDS) have tried to approach the problem of these high-risk ventricular tachyarrhythmias. Although at 3 years, the ICD in AVID demonstrated a significant relative risk reduction over amiodarone of 31.5%, CIDS could not duplicate this finding. At 3 years, the relative risk reduction conferred by the ICD over amiodarone in CIDS was only 13.7%. A careful analysis of both studies suggests that CIDS was insufficiently powered to demonstrate statistically significant benefits similar to those shown by AVID, and furthermore, seemed to include an undetermined number of low-risk VT patients. The problem in the CIDS trial in this regard was the recruitment of patients in whom the inclusion criteria were met by the arrhythmias induced during the electrophysiology stimulation study, but which did not exist in real life. In addition CIDS included 14% of patients with (1) undocumented syncope and inducible monomorphic sustained VT; or (2) long runs of spontaneous nonsustained VT. Under these circumstances, the therapeutic implications of AVID remain unchallenged.

Anti-Arrhythmia Agents↗
PubMed2000

Hexaaquacobalt(II) bis(4-toluenesulfonate).

The title compound, [Co(H(2)O)(6)](CH(3)C(6)H(4)SO(3))(2), has a structure where the metal atom is surrounded by six molecules of water forming the cation and the anion is deprotonated 4-toluenesulfonic acid. The Co atom is in a nearly regular octahedral coordination geometry, with Co-O distances between 2.0529 (14) and 2.0810 (16) A, and angles ranging from 87.25 (9) to 92.75 (9) degrees. The supramolecular structure consists of parallel layers of cations and anions. The anions are arranged with their sulfonate groups directed towards the cation layer in an alternating fashion and form hydrogen bonds with the water molecules of the cation.

Journal Article↗
PubMed2000

Analysis of pitch deposits produced in kraft pulp mills using a totally chlorine free bleaching sequence.

Two organic deposits accumulated in a Kraft pulp mill during pulping of Eucalyptus globulus wood and throughout a TCF (totally chlorine free) bleaching sequence were characterized. One deposit was collected after cooking and an oxygen delignification stage while the other was collected after bleaching with hydrogen peroxide. The deposits were Soxhlet extracted with acetone, and the extracts redissolved in chloroform and subsequently analyzed by gas chromatography (GC) and GC-mass spectrometry (MS) using short and medium length high temperature capillary columns, respectively. On the other hand, the insoluble residues left after the acetone extraction were analyzed by Curie-point flash pyrolysis-GC-MS and by pyrolysis-methylation-GC-MS. The compounds identified in the deposits arise from the E. globulus wood lipophilic extractives that survive the pulping and bleaching processes. Triglycerides were completely hydrolyzed during the Kraft cooking and the fatty acids dissolved. Steroids (alcohols, hydrocarbons, ketones and esters) and waxes were the main components in the deposit collected after the oxygen delignification stage. After the bleaching with hydrogen peroxide, content of the waxes were reduced and fatty acids appeared. High amounts of fatty acids salts were also identified in the deposit collected after the oxygen stage, and in minor amounts in the deposit collected after hydrogen peroxide bleaching. In contrast, this deposit was mainly made up of high amounts of lignin-derived phenolic moieties.

Acetone↗
PubMed2000

Development of improved soluble inhibitors of FasL and CD40L based on oligomerized receptors.

TNF receptor family members fused to the constant domain of immunoglobulin G have been widely used as immunoadhesins in basic in vitro and in vivo research and in some clinical applications. In this study, we assemble soluble, high avidity chimeric receptors on a pentameric scaffold derived from the coiled-coil domain of cartilage oligomeric matrix protein (COMP). The affinity of Fas and CD40 (but not TNFR-1 and TRAIL-R2) to their ligands is increased by fusion to COMP, when compared to the respective Fc chimeras. In functional assays, Fas:COMP was at least 20-fold more active than Fas:Fc at inhibiting the action of sFasL, and CD40:COMP could block CD40L-mediated proliferation of B cells, whereas CD40:Fc could not. In conclusion, members of the TNF receptor family can display high specificity and excellent avidity for their ligands if they are adequately multimerized.

Animals↗
PubMed2000

Activational role of cannabinoids on movement.

Cannabinoid's major effect on movement is hypoactivity. Nevertheless, a biphasic excitatory/inhibitory effect of cannabinoids on movement has been repeatedly acknowledged. However, the literature is lacking a detailed description of such an effect. In this study, we performed a dose-response study of the effects of Delta(9)-tetrahydrocannabinol on movement. Immediately after the administration of vehicle or a dose of Delta(9)-tetrahydrocannabinol (0.2, 0.5, 1, 1.5, 2, 2.5, 3, 4, or 5 mg/kg), the animal was placed in an activity monitor and observed for 1 h. Several parameters were recorded. The horizontal and vertical activities were measured as the number of photobeams broken between the photocells on the walls of an activity monitor. The number of wet dog shakes, scratches with hindpaw, mouth movements, forepaw flutters were also recorded, as was the amount of time in minutes that each subject spent grooming. The number of fecal boluses was recorded as an index of autonomic activity. Each animal was subsequently tested for catalepsy in the bar test. A triphasic effect was observed: low doses of the cannabinoid receptor agonist Delta(9)-tetrahydrocannabinol (0.2 mg/kg) decreased locomotor activity while higher doses (1-2 mg/kg) dose-dependently stimulated movement until catalepsy emerged (2.5 mg/kg) accompanied by decreases in activity.

Animals↗
PubMed2000

Bis[2-(diphenylphosphinoyl)benzene] disulfide.

The title compound, [2-Ph(2)P(O)C(6)H(4)S](2) or C(36)H(28)O(2)P(2)S(2), obtained by electrochemical oxidation of 2-(diphenylphosphino)benzenethiol, has twofold crystallographic symmetry. Principal dimensions include S-S 2.0212 (15) A, S-C 1.786 (3) A and C-S-S-C 81.34 (14) degrees.

Journal Article↗
PubMed2000

[Extra-intestinal salmonella infections in kidney transplant patients].

Immunosuppression to prevent rejection of solid organ transplants is accompanied by an increased risk of infections. The most frequent diseases include cytomegalovirus as well as bacterial infections of the urinary tract and the lung. The rate of enteric salmonella infections is increased in transplant patients. We report on four cases of extraintestinal salmonellosis after kidney allotransplantation.

Aged↗
PubMed2000

Role of the superior colliculus in the motor effects of cannabinoids and dopamine.

We studied the cellular distribution of CB1 cannabinoid receptors in the superior colliculus of the rat using an antibody raised against the N-terminal of the receptor. The effect of unilateral cannabinoid receptor stimulation in the intermediate layers of the superior colliculus on rotational behavior in rats was also explored. The antibody against CB1 receptors outlined the crossed descending system of the superior colliculus (predorsal bundle output system) as well as the collicular commisure. The potent cannabinoid agonist CP55,940 (5 microgram/0.25 microliter) induced strong contralateral turning when microinjected unilaterally into the lateral intermediate layers of the superior colliculus. The levels of turning obtained with the intracollicular administration of the cannabinoid were comparable to the highest levels obtained with dopamine agonists in the basal ganglia. The D(2) dopamine agonist quinpirole or the D(1) dopamine agonist SKF82958 reversed this contralateral rotation but failed to affect motor behavior on their own. A new motor pathway for cannabinoids is discussed.

Analgesics↗
PubMed2000

Spontaneous osteonecrosis of the medial compartment of the knee: a MRI follow-up after conservative and operative treatment, preliminary results.

Symptoms in patients suffering from spontaneous osteonecrosis of the knee (SONK) may be reduced by high tibial osteotomy (HTO). However, the fate of the necrotic lesion is unknown and needs further investigation. We conducted a prospective study to evaluate magnetic resonance imaging (MRI) changes after operative and nonoperative treatment. Ten consecutive patients suffering from SONK of the medial compartment were given two treatment options: either HTO (n = 6) or conservative treatment with partial weight bearing for 3 months (n = 4). We measured the greatest extent of well-defined subchondral low signal intensity abnormality, considered to represent necrosis, and the surrounding area of intermediate signal intensity, considered to represent perifocal bone marrow edema, on T1-weighted coronal MRI images before and after treatment. The MRI follow-up period was 17.5 months (range 12-27) in the HTO group and 14.5 months (range 8-25) in the nonoperative group. At follow-up the MRI evaluation revealed a decrease in the low signal intense areas (necrosis) in five of the six patients in the HTO group. Only one of the four nonoperative patients showed a decrease in the low signal intense area. The intermediate intense areas (edema) decreased in all patients in the HTO group and in three of four in the nonoperative group. The mean decrease in the area of perifocal edema was significantly greater in the HTO group than in the nonoperative group (P = 0.019). No statistically significant difference was found for the area of necrosis between the two groups (P = 0.171). A clinical improvement was observed in all patients of the HTO group but in only two of the four patients of the nonoperative group. We conclude that the decrease in perifocal bone marrow edema seems to be associated with improved patient comfort. The MRI appearance of the necrotic lesion does not alter with either treatment mode.

Aged↗
PubMed2000

Candida infection of cerebrospinal fluid shunt devices: report of two cases and review of the literature.

Use of CSF shunt devices is a common practice in neurosurgery, and infection of the shunt is the most frequent complication. In spite of the fact that bacteria are the most widely implicated pathogens, reports of fungal infections, especially due to Candida sp., have increased in recent years. Their reported frequency ranges between 6% and 17%. Many factors have been implicated in the pathogenesis of Candida meningitis, such as broad spectrum antibiotics used in the treatment of a bacterial meningitis, steroids and indwelling bladder and intravenous catheters. The treatment of Candida meningitis still consists of systemic antifungal agents and removal of the shunt.

Adolescent↗