Biomedical subjects

D Morales

Publications and source records attributed to D Morales.

At least 19 recordsLinked to original sources

PubMed2006

Oil/water droplet formation by temperature change in the water/c(16)e(6)/mineral oil system.

Droplet sizes of oil/water (O/W) nanoemulsions prepared by the phase inversion temperature (PIT) method, in the water/C16E6/mineral oil system, have been compared with those given by a theoretical droplet model, which predicts a minimum droplet size. The results show that, when the phase inversion was started from either a single-phase microemulsion (D) or a two-phase W+D equilibrium, the resulting droplet sizes were close to those predicted by the model, whereas, when emulsification was started from W+D+O or from W+D+Lalpha (Lalpha = lamellar liquid crystal) equilibria, the difference between the measured and predicted values was much higher. The structural changes produced during the phase inversion process have been investigated by the 1H-PFGSE-NMR technique, monitoring the self-diffusion coefficients for each component as a function of temperature. The results have confirmed the transition from a bicontinuous D microemulsion at the hydrophile-lipophile balance (HLB) temperature to oil nanodroplet dispersion in water when it is cooled to lower temperatures.

Emulsions↗

PubMed2006

Knowledge about sepsis among training-grade doctors.

BACKGROUND: Prescribing of antibiotics, often in the empirical setting, frequently falls on training-grade or junior doctors, who are often the least experienced in this. Indeed, improving the knowledge base of training-grade doctors or senior medical students through education has been identified as one of the key measures to improve antibiotic prescribing behaviour. METHODOLOGY: We undertook two descriptive questionnaire- and interview-based surveys (1999 and 2003) of prescribing training-grade doctors in a teaching hospital in north-east Scotland to determine their knowledge level regarding various sepsis definitions, sources of local information used when prescribing an antimicrobial, and awareness of the cost difference between intravenous and oral antibiotics. A total of 55 junior doctors in a large teaching hospital participated in the survey in 1999 and 78 participated in 2003. INTERVENTIONS: Between the two audits, which were conducted 4 years apart, several initiatives were introduced to improve the education and support related to antibiotic prescription. RESULTS: There has been a significant improvement in doctors' knowledge regarding various sepsis definitions, whether the infection was hospital or community acquired, empirical choice, dose, route of administration and monitoring of the antibiotic, and options for drug hypersensitivity. More training-grade doctors (approximately 29%) used the desired locally derived sepsis protocol, which guides the prescriber through sepsis recognition. There was no significant improvement in the percentage of doctors who recognized that parenteral antimicrobials were more expensive (approximately 10-fold) than oral antimicrobials (63.7% in 1999, 64.2% in 2003). CONCLUSIONS: Overall, there was a significant improvement in doctors' understanding of sepsis and knowledge of the source of information that they utilized to select the antibiotic of choice, although the majority did not acknowledge the price difference between intravenous and oral forms of antibiotics.

Anti-Bacterial Agents↗

PubMed2006

Ischemic preconditioning and kidney transplantation: in vivo nitric oxide monitoring in a rat ischemia-reperfusion experimental model.

Direct nitric oxide measurement in live tissue would help us to understand its role in ischemia-reperfusion injury and its relationship to ischemic preconditioning (IP). We constructed four experimental groups of ischemia-reperfusion in the rat kidney: G1 were controls; G2, 1 hour of renal ischemia; G3 and G4: one or two 15/10 minute cycles, respectively, of IP prior to 1 hour of ischemia. Real-time in vivo nitric oxide measurements were compared with functional parameters of kidney damage at 24 hours. The peaks of nitric oxide production in the IP periods increased less in the rising curve of nitric oxide production during the 1 hour ischemia time. No improvement in the IP groups was observed based on serum creatinine levels at 24 hours.

Animals↗

PubMed2005

Health-related quality of life of patients with HIV: impact of sociodemographic, clinical and psychosocial factors.

OBJECTIVES: This study aims to analyse how a wide group of clinical, social, demographic and psychological factors are related to both physical and mental quality of life in HIV + patients. DESIGN: A cross-sectional study was carried out of 320 HIV + patients in antiretroviral treatment who attended infectious diseases units in four hospitals in the region of Andalusia (Spain). METHODS: Health-Related Quality of Life was measured by the MOS-HIV. Included as independent variables were: sociodemographic variables, variables related to antiretroviral therapy, psychosocial variables like social support (Duke-UNC-11) and psychological morbidity (GHQ-28), variables related to main risk behaviours and clinical variables. RESULTS: In the multiple linear regression analysis, a better PHS quality of life was found to be associated with the absence of mental illness, social support, not being an intravenous drug user and using more than one type of non-injectable drug. A better quality of life, in mental terms, was found to be associated with fewer years as a non-intravenous drug user, having social support, absence of mental illness, not being an intravenous drug user taking only one additional pill, not having any difficulty in taking the medication, and being female. CONCLUSIONS: The study of other non-biological factors that may be related to quality of life has been limited practically to social support and the emotional state. This study highlights the importance of these factors independently from the clinical state, as well as the existence of other psychological and behavioural factors that are also related.

Activities of Daily Living↗

PubMed2005

Visceral leishmaniasis: diagnosis by ultrasound-guided fine needle aspiration of an axillary node.

A 77-year-old woman presented with fever up to 39 degrees C and acute pain in the left upper quadrant and renal fossa. Full blood count and biochemical screen revealed a haemoglobin (Hb) of 9.8 g dl(-1), an increased erythrocyte sedimentation rate and an elevated lactate dehydrogenase, all other parameters were normal. Thoracic and abdominal CT demonstrated two enlarged lymph nodes in the left axilla, and splenic infarcts. Ultrasound-guided fine needle aspiration of one of the axillary lymph nodes revealed macrophages filled with leishmanias.

Aged↗

PubMed2005

Factors related to the process of seeking and completing treatment for drug abuse (qualitative methods in drug abuse research).

Numerous studies have demonstrated the effectiveness of drug abuse treatment. Yet many drug abusers do not enter treatment, many who do enter leave prematurely, and relapse following treatment is common. Understanding motivation for change and treatment readiness is key to understanding how to induct and engage drug users in treatment. To the extent that treatment programs focus initially on reducing drug use, rather than psychosocial problems that motivate individuals to seek treatment, treatment programs may fail to meet the primary needs of users and thus fail to attract or engage them. Outcomes of substance abuse treatment programs historically have been measured by successful program completion, reduced drug use and illegal activity, and improved social functioning (employment, education etc). There is minimal reference to client expectations of treatment and factors that influenced treatment-seeking behavior. Studies that have assessed client dropout from substance abuse treatment have generally focused upon quantitative measures that attempt to determine what types of clients drop out or stay, or what types of characteristics best predict client dropout. Qualitative methods are the most appropriate to fill these gaps in substance abuse treatment research.

Humans↗

PubMed2004

Assessment of genetic, antigenic and pathotypic criteria for the characterization of IBDV strains.

The aim of this work was the selection and comparison of representative infectious bursal disease virus (IBDV) strains. Nine strains of IBDV, isolated at different times and from different geographic regions of Europe and China, were characterized. Batches of all strains were prepared following standardized protocols and checked for the absence of contaminating viruses. Criteria used for their characterization were: (i) the nucleotide sequence of the VP2 variable region, (ii) binding to a panel of neutralizing monoclonal antibodies in antigen capture enzyme-linked immunosorbent assays, and (iii) virulence in specific pathogen free chickens after infection with a standardized number of median embryo infective doses. Based on the first two criteria, two of nine strains were classified as classical virulent (cv) IBDV (F52/70, Cu-1wt), and five as very virulent (vv) IBDV (849VB, 96108, HK46, GX, Harbin). Remarkably, although a clear-cut difference was demonstrable between European cvIBDV (F52/70 and Cu-1wt) and vvIBDV (849VB and 96108) strains, there was a continuum in the pathogenicity of Chinese vvIBDVs. Our results indicate the probable existence of differences in virulence within IBDV lineages determined on the basis of antigenic typing using monoclonal antibodies and the alignment of the VP2 sequences. This indicates limitations in the analysis of IBDV pathotypes based on the VP2 variable region and emphasizes that these criteria may not be sufficient for the classification of IBDV strains.

Amino Acid Sequence↗

PubMed2003

Effects on run-off water quantity and quality of urban organic wastes applied in a degraded semi-arid ecosystem.

Biosolids and composted municipal solid wastes were surface-applied (0 and 80 Mg ha(-1)) to a degraded soil in a semi-arid environment to determine their effects on the quantity and quality of run-off water. Three and 4 years after application, a simulated rainfall was performed (intensity=942.5 ml min(-1) and kinetic energy=3.92 J m(-2)) on 0.078 m(2) plots using a portable rainfall simulator. The run-off from the different treatment plots was collected and analysed. The type of treatment was highly related to infiltration, run-off and sediment production. The biosolid-treated plots showed the minimum value of total run-off, maximum time to the beginning of run-off and maximum run-off ratio (the relationship between total rainfall and run-off). The MSW-treated plots showed values intermediate between biosolid-treated plots and control plots. Soil losses were also closely related to treatment type. Control plots showed the maximum sediment yield, MSW-treated plots showed intermediate values, and biosolid plots the minimum values for washout. The concentrations of NH(4)-N and PO(4)-P in the run-off water were significantly higher in the treated plots than in control plots. The highest PO(4)-P value, 0.73 mg l(-1), was obtained in the soil treated with biosolids; NO(3)-N concentration also increased significantly with respect to the control and MSW treatments. NH(4)-N concentrations of 15.6 and 15.0 mg l(-1) were recorded in the soils treated with biosolids and MSW, respectively, values approximately five times higher than those obtained in run-off water from untreated soil. However, the concentrations of all these constituents were lower than threshold limits cited in water quality standards for agricultural use. With the exception of Cu, all trace metals analysed in the run-off water were below detection limits.

Conservation of Natural Resources↗

PubMed2003

188Re-labeled anti-epidermal growth factor receptor humanized monoclonal antibody h-R3: labeling conditions, in vitro and in vivo stability.

The use of antibodies as targeting agents for the delivery of radioisotopes to tumors is an appealing concept that has received widespread attention since the advent of monoclonal antibody (mAb) technology. The present study describes the (188)Re-direct labeling of anti-epidermal growth factor receptor (EGF-R) humanized mAb h-R3; the analytical methods for quality control of radiopharmaceuticals such as instant thin layer chromatography-silica gel (ITLC-SG); the immunoreactivity and biological recognition of the target antigen assessment of the radiolabeled molecule using flow cytometry analysis; in vitro stability studies using saline 0.9% solution, cysteine, diethylenetriaminepentaacetic acid (DTPA), human serum and human serum albumin (HSA) 1% challenge; and the assessment of in vivo stability through biodistribution studies in normal Balb/c mice. No fragmentation of the reduced molecules was found using 2-ME as a reducing agent. Labeling efficiency was greater than 98.5 +/- 0.6% of rhenium-188 (188Re) bound to IgG1 after 5 h, as determined by paper chromatography in saline 0.9% solution. Radiocolloids determined by albumin impregnated ITLC was 1.04 +/- 0.07% in all cases. The biological activity measured by flow cytometry analysis showed an immunoreactivity fraction and the biological recognition of the target antigen overexpressed on H-125 human lung adenocarcinoma cell line greater than 87%. Challenge studies with cysteine, DTPA, human serum and HSA 1% demonstrated no evidence of transcomplexation of 188Re to DTPA or HSA and showed that 30% and 85% of the 188Re-radiolabeled was transcomplexed to human serum and to 100 mM cysteine after 24 h for human serum and 1 h incubation for cysteine at 37 masculine C, respectively. Biodistribution studies indicated no accumulation of the radiolabeled antibodies in normal organs.

Animals↗

PubMed2002

Persistence of the antihypertensive efficacy of amlodipine and nifedipine GITS after two 'missed doses': a randomised, double-blind comparative trial in Asian patients.

Suboptimal management of hypertension is often a result of poor patient compliance in the form of missed doses of their antihypertensive medication. This multicentre, randomised, double-blind, parallel-group trial was designed to compare the persistence of the antihypertensive efficacy of the amlodipine and nifedipine gastrointestinal therapeutic system (GITS) after two 'missed doses', and also to compare the drugs' overall efficacy and safety in Asian patients with mild-to-moderate essential hypertension. Following a 2-week placebo run-in period, 222 patients were randomised to receive either amlodipine (5 mg daily, increased after 6 weeks if necessary to 10 mg daily, n=109) or nifedipine GITS (30 mg daily, increased after 6 weeks if necessary to 60 mg daily; n=113) for 12 weeks. A placebo was then substituted for further 2 days with continuous ambulatory blood pressure (BP) monitoring. The increases in the last 9 h of mean ambulatory BP on day 2 after treatment withdrawal were significantly less with amlodipine than with nifedipine GITS: 4.4+/-7.0 vs 11.2+/-11.3 mmHg for systolic BP (P<or=0.0001) and 2.4+/-6.3 vs 6.0+/-6.0 mmHg for diastolic BP (P<or=0.0002). Significant differences between the two drugs in mean 24-h ambulatory BP levels were already evident on day 1 after withdrawal, even though there were no significant differences on the final day of treatment. No differences in safety parameters were observed, and neither drug caused any serious or severe treatment-related adverse events. In conclusion, amlodipine provides greater protection than nifedipine GITS against loss of BP control following missed doses.

Amlodipine↗

PubMed2001

Differences in the effects of flooding the soil early and late in the photoperiod on the water relations of pot-grown tomato plants.

The water relations of potted tomato plants (Lycopersicon esculentum Mill. cv INCA 9(1)) submitted to two flooding/recovery cycles imposed at the beginning and at the end of photoperiod were studied under controlled conditions. In both experiments, flooding induced stomatal closure due to leaf dehydration linked to a lowered root hydraulic permeability. Thus, during the early hours of flooding there was an effective negative hydraulic message from O(2) deficient roots. However, when the soil was drained stomata did not re-open until some time after leaf water potential and leaf turgor potential returned to normal, supporting the view that chemical messages predominate. Flooding imposed at the end of photoperiod induced a delay in g(l), Psi(l), and Psi(p,) recovery.

Journal Article↗

PubMed2001

The inverted neurogenetic gradient of the mammalian isocortex: development and evolution.

In this paper we review recent evidence on the molecular control of cell migration in the isocortex, and present an hypothesis for the evolutionary origin of the inside-out neurogenetic gradient of this structure. We suggest that there are at least two key factors involved in the acquisition of the inside-out gradient: (i) the expression of the protein reelin, which arrests the migration of cortical plate cells by detaching them from the radial glial fiber. This permits younger neurons to use the same fiber to migrate past the previous neurons; and (ii) the second factor is an intracellular signaling pathway dependent on a cyclin-dependent protein kinase (Cdk5). Cdk5 may work by inhibiting N-cadherin mediated cell aggregation as young cells cross the cortical plate, permitting them to move to the more superficial layers. Interestingly, the mutation in Cdk5 affects the migration of only those cells belonging to superficial layers, which are considered to be an evolutionary acquisition of the mammalian isocortex.

Animals↗

PubMed2001

Gas exchange characteristics of a Canarian laurel forest tree species (Laurus azorica) in relation to environmental conditions and leaf canopy position.

Diurnal courses of gas exchange were measured over a 1-year period in fully expanded current-year leaves in the upper (sun-exposed, 18 m above ground) and the lower (shaded, 12 m above ground) canopy of Laurus azorica (Seub.) Franco, a major canopy species of the Canarian laurel forest in Tenerife, Canary Islands, Spain. Laurus azorica exhibited high leaf plasticity in gas exchange characteristics, with a maximum carbon assimilation rate (Amax) of shade leaves about 50% that of sun leaves. This difference reflects the high leaf area index (LAI) of the stand and the correspondingly sharp light attenuation with increasing canopy depth. In sun leaves, Amax peaked at about 11 micromol m-2 s-1 and maximum transpiration (E) was about 8 mmol m-2 s-1, which corresponded with a maximum stomatal conductance (gs) of about 650 mmol m-2 s-1. Mean maximum instantaneous water-use efficiency (WUE) was 1.5 mmol mol-1 and the mean maximum A/gs was 20-35 micromol mol-1. Mean minimum internal CO2 concentration (Ci) was 225 micromol mol-1. Although high air vapor pressure deficit (VPD) caused a small decrease in gs, it remained high enough to maintain relatively high A and E. These gas exchange characteristics indicate a non-conservative use of water, which is appropriate for a species subject to droughts that are mild or of short duration. In this respect, Laurus azorica differs from its congener, L. nobilis L., of the Mediterranean region and other shrubs growing in Mediterranean-type climates in California and Chile that have to withstand more severe or more prolonged droughts.

Atlantic Islands↗

PubMed2001

Screening for retinopathy of prematurity employing the retcam 120: sensitivity and specificity.

OBJECTIVES: To compare the method of photographic screening using the RetCam 120 to the standard method of screening for retinopathy of prematurity (ROP) by ophthalmologic examination. METHODS: A total of 100 RetCam 120 photoscreening examinations of the retina were performed on 32 premature infants. These were stored in a separate file from which all identifying information was removed. At this same examination, a detailed ophthalmological evaluation, employing the indirect ophthalmoscope with scleral depression, was performed by an experienced examiner. Masked examiners performed an evaluation of the fundus photographs to identify presence or absence of ROP, the location and extent of the disease, and the presence or absence of plus disease. These data were then compared with the results of the ophthalmological examination to determine the specificity, sensitivity, and the positive and negative predictive value (PPV and NPV) of the method. RESULTS: Retinopathy of prematurity was detected in 68 of 100 subjects by ophthalmologic examinations and in 58 of 100 subjects' photoscreening examinations. No ROP was detected in 32 of 100 subjects. The sensitivity of the method was 56 (82.4%) of 68 and the specificity was 30 (93.8%) of 32. The PPV was 96.6%; NPV, 76.9%. CONCLUSIONS: The sensitivity of the method was low. The ROP that was missed was peripheral stage 1 or stage 2 disease in peripheral zone 2 or zone 3. This was largely due to the technical limitations of the speculum-camera interface preventing a better view of the periphery. The ROP cases that were missed by the photographic examination regressed spontaneously on follow-up. No disease more posterior to peripheral zone 2 was overlooked. These results detail the accuracy of the method employing the technique of photoscreening as a potential substitute for detailed ophthalmological examination. At present there are clear technical limitations to such a substitution. The study is part of an ongoing project to determine the feasibility of employing neonatal nurses trained to take digitized images of the premature infant's retina and telemeter the results to be read by an experienced ophthalmologist remote from the site.

False Negative Reactions↗

PubMed2000

Serine and glycine transport in fetal ovine hepatocytes.

The role of hepatic serine and glycine transport in the regulation of the biosynthesis of serine by the fetal liver has not been studied. The goal of this study was to characterize serine and glycine transport and utilization at physiologic concentrations in primary cultures of fetal ovine hepatocytes. Primary culture of hepatocytes from mid gestation ( approximately 90 days) and term ( approximately 135 days) fetal sheep were studied after overnight serum free culture. At both gestational ages, the initial rate for sodium dependent 300 microM serine transport (1697+/-131 pmoles/min/mg protein at mid, 1765+/-544 at term) was fourfold greater than sodium dependent 300 microM glycine transport (309+/-54 at mid, 579+/-252 at term). At physiologic concentrations (300 microM), 69+/-7% of serine and 49+/-8% of glycine transport was sodium dependent. At term, sodium dependent serine transport has a V(max) of 1751+/-348 pmoles/min/mg protein and a K(m) of 159+/-111 microM. Sodium independent serine transport has a V(max) of 904+/-185 and a K(m) of 416+/-188 microM. Sodium dependent glycine transport has a V(max) of 410+/-69 and a K(m) of 2290+/-895 microM while sodium independent glycine transport exhibits non-saturable kinetics. Glycine (300 microM) sodium dependent transport was not inhibited by methyl-AIB while sodium dependent 300 microM serine transport was inhibited (31%). n-Ethylmaleimide inhibited sodium dependent serine and glycine transport by 36+/-9% and 37+/-2% respectively in term hepatocytes. Cysteine inhibited sodium dependent serine transport by 37%. Sodium independent glycine transport at 300 microM was higher in low glucose (1.1 mM) medium (881+/-76 pmoles/min/mg protein) compared to high glucose (5.5 mM) medium (510+/-60 P=0.004). There were no significant differences in serine or glycine incorporation into RNA, DNA, glycogen or lipid and protein. The predominance of serine transport over glycine at physiologic concentrations suggests that inward cellular amino acid transport of serine and glycine is not likely to be a regulatory mechanism that would favor serine biosynthesis in fetal ovine hepatocytes.

Animals↗

PubMed2000

Spatiotemporal profile of synaptic activation produced by the electrical and visual stimulation of retinal inputs to the optic tectum: a current source density analysis in the pigeon (Columba livia).

The optic tectum of the pigeon is a highly organized, multilayered structure that receives a massive polystratified afference of at least five different populations of retinal ganglion cells and gives rise to various anatomically segregated efferent systems. The synaptic organization of retino-tectal circuitry is, at present, mostly unknown. To investigate the spatiotemporal profile of synaptic activation produced by differential (electrical and visual) stimulation of the retinal inputs, we performed a high-spatial-resolution current source density analysis in the optic tectum of the anaesthetized pigeon. Electrical stimuli consisted of brief pulses of different durations applied to the optic nerve head, while visual stimuli consisted of light flashes of different intensities. Electrical stimulation generated sinks confined to retinorecipient layers. The temporal structure, spatial location and thresholds of these sinks indicated that they are all due to primary tectal synapses of retinal fibers with different conduction velocities. Sinks evoked by the fastest retinal axons were more superficially located than sinks produced by slower retinal fibers. Visual stimulation, on the other hand, resulted in a more complex pattern of current sinks, with various sinks located in the retinorecipient layers and also well below. Visual stimulation induced action potentials at superficial as well as deep tectal levels. We conclude that electrical stimulation activates most of the populations of ganglion cells as well as their primary tectal synapses, but is unable to elicit a significant activation of secondary tectal synapses. Visual stimulation, on the contrary, activates just some of the incoming retinal populations, but in a way that produces noticeable secondary activation of intratectal circuits. Laminar segregation of retinally evoked tectal activity, as reported here, has also been found in other vertebrates. Similarities and differences with previous studies are discussed.

Animals↗

PubMed2000

Papillary cystic tumor of the pancreas coexisting with hairy cell leukemia.

The coexistence of a pancreatic papillary cystic tumor with hairy cell leukemia is reported. To the best of our knowledge this association has never been published. A 41-year-old man diagnosed with hairy cell leukemia developed a second malignancy that corresponded to a papillary cystic pancreatic tumor. The patient underwent splenectomy and a tumoral surgical resection, and is currently well at 21 months follow-up. A pathogenetic relationship between the two malignancies was not demonstrated. Hairy cell leukemia has been reported to be associated to a great number of different second malignancies. In contrast, only two papillary cystic tumors of the pancreas have been described associated to a second neoplasm, a papillary thyroid carcinoma and a colonic carcinoma. This unusual benign or low-grade malignant pancreatic tumor more commonly occurs in the tail of the pancreas of young women. We want to stress the unusual presentation of this pancreatic tumor affecting the head of the gland in a male patient as well as its coexistence with a hairy cell leukemia.

Adult↗

PubMed1999

Comparison of biological activities of natural and recombinant chicken interferon-gamma.

In recent years, chicken interferon-gamma (ChIFN-gamma) has been identified and cloned from a chicken T cell line. In this study, recombinant ChIFN-gammma produced in the baculovirus and prokaryotic (Escherichia coli) expression systems were characterized and their activity was compared to that of naturally ChIFN-gamma produced by mitogen-activated splenic T cells. The baculovirus-derived ChIFN-gamma protein (Bac-ChIFN-gamma) proved to have physiochemical properties and biological activities similar to those of natural ChIFN-gamma. Indeed, Bac-ChIFN-gamma was able to inhibit the replication of cytolytic viruses in chicken embryo fibroblasts and to activate macrophages, as was determined by nitric oxide production. Levels ranging between 100 and 300 microg/ml of BacChIFN-gamma could be obtained in the supernatants of infected insect cells. On the other hand, yields of the E. coli produced ChIFN-gamma rarely exceeded 100 microg/ml after purification steps and although it was also able to activate the HD11 macrophage cell line in a specific manner, no anti-viral activity could be demonstrated. Therefore, the baculovirus expression system is an appropriate system for the high-level expression of biologically active ChIFN-gamma and will allow further studies of the immunomodulatory and therapeutic effects of this cytokine in vivo.

Animals↗