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Biomedical subjects

J Pou

Publications and source records attributed to J Pou.

At least 19 recordsLinked to original sources
PubMed2006

In vitro testing of Nd:YAG laser processed calcium phosphate coatings.

Nd:YAG laser cladding is a new method for deposition of a calcium phosphate onto metallic surfaces of interest in implantology. The aim of this study was to compare the biologic response of MG-63 human osteoblast-like cells grown on Ti-6Al-4V substrates coated with a calcium phosphate layer applied using different methods: plasma spraying as reference material and Nd:YAG laser cladding as test material. Tissue culture polystyrene was used as negative control. The Nd:YAG laser clad material showed a behaviour similar to the reference material, plasma spray, respective to cell morphology (SEM observations), cell proliferation (AlamarBlue assay) and cytotoxicity of extracts (MTT assay). Proliferation, as measured by the AlamarBlue assay, showed little difference in the metabolic activity of the cells on the materials over an 18 day culture period. There were no significant differences in the cellular growth response on the test material when compared to the ones exhibited by the reference material. In the solvent extraction test all the extracts had some detrimental effect on cellular activity at 100% concentration, although cells incubated in the test material extract showed a proliferation rate similar to that of the reference material. To better understand the scope of these results it should be taken into account that the Nd:YAG clad coating has recently been developed. The fact that its in vitro performance is comparable to that produced by plasma spray, a material commercially available for more than ten years, indicates that this new laser based method could be of commercial interest in the near future.

Alloys↗
PubMed2006

Biological stability and osteoconductivity in rabbit tibia of pulsed laser deposited hydroxylapatite coatings.

A comparative study of the biological stability and the osteoconductivity of hydroxylapatite (HA) coatings produced by pulsed laser deposition (PLD) and plasma spraying (PS) was conducted. Three different implant groups were used: grit-blasted titanium rods coated with HA-PLD (2-microm-thick), grit-blasted titanium rods coated with HA-PS (50-microm-thick), and uncoated. Implantation took place into the proximal tibia of 12 mature New Zealand White rabbits for 24 weeks. Samples were evaluated using descriptive histology and histomorphometry. While HA-PS implants showed considerable instability and reduction in thickness after 24 weeks, but no statistical difference to the titanium group, the HA-PLD group showed a significant higher amount of bone apposition (Scheffé test, p<0.05) than the other two groups, without signs of degradation or dissolution. Remarkably, after 6 months, the almost intact thin pulsed laser deposited coating could be observed by electron microscopy in extended areas.

Animals↗
PubMed2003

Calcium phosphate coatings obtained by Nd:YAG laser cladding: physicochemical and biologic properties.

The plasma spray (PS) technique is the most popular method commercially in use to produce calcium phosphate (CaP) coatings to promote fixation and osteointegration of the cementless prosthesis. Nevertheless, PS has some disadvantages, such as the poor coating-to-substrate adhesion, low mechanical strength, and brittleness of the coating. In order to overcome the drawbacks of plasma spraying, we introduce in this work a new method to apply a CaP coating on a Ti alloy using a well-known technique in the metallurgical field: laser surface cladding. The physicochemical characterization of the coatings has been carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). The biologic properties of the coatings have been assessed in vitro with human osteoblast-like MG-63 cells. The overall results of this study affirm that the Nd:YAG laser cladding technique is a promising method in the biomedical field.

Alloys↗
PubMed2003

Micro- and nano-testing of calcium phosphate coatings produced by pulsed laser deposition.

Micro- and nano-testing methods have been explored to study the thin calcium phosphate coatings with high adhesive strength. The pulsed laser deposition (PLD) technique was utilised to produce calcium phosphate coatings on metal substrates, because this type of coatings exhibit much higher adhesive strength with substrates than conventional plasma-sprayed coatings. Due to the limitations of the conventional techniques to evaluate the mechanical properties of these thin coatings (1 microm thick), micro-scratch testing has been applied to evaluate the coating-to-substrate adhesion, and nano-indentation to determine the coating hardness and elastic modulus. The test results showed that the PLD produced amorphous and crystalline HA coatings are more ductile than titanium substrates, and the PLD coatings are not delaminated from the substrates by scratch. Also, the results showed that the crystalline HA coating is superior in internal cohesion to the amorphous one, even though the lower elastic modulus of amorphous coating could be more mechanically compatible with natural bone.

Calcium Phosphates↗
PubMed2002

Alloying of hydroxyapatite onto Ti6Al-4V by high power laser irradiation.

In the biomedical field, the synthetic hydroxyapatite [Ca(10)(PO)(4)(OH)(2)], with similarity to the inorganic component of bone but brittle, has been considered as the appropriate coating on stronger implant materials, such as metallic implants, for presenting a surface which is conductive to bone formation. Many industrial and laboratory techniques were developed to apply hydroxyapatite onto metallic substrates, such as electrophoretic deposition, ion sputtering, hot isostatic pressing, pulsed laser deposition and the only widely used method commercially available: plasma spraying. This work presents a new approach on how to bind calcium phosphate (CaP) to the Ti alloy with a well-known technique in the metallurgical field: laser surface alloying, in order to overcome the drawbacks of plasma spraying. The analysis of the results obtained and the description of the phenomena that take place in the coating process will complete this explorative study.

Journal Article↗
PubMed2000

Diagnostic approach to inborn errors of metabolism in an emergency unit.

OBJECTIVES: Our aim was to review the patients with a final diagnosis of inborn error of metabolism (IEM) who had previously required clinical attention at the emergency unit of our hospital over the last 9 years. METHODS: From the 184 patients with IEM, we selected 53 patients who required clinical attention at the EU as a prior step that led to a definitive diagnosis. We analyzed the frequency of the various IEM, their clinical presentations, and basic biochemical abnormalities in decompensation. RESULTS: We detected a predominance of neurologic signs (in 85% of our patients), followed by digestive symptoms (58.5%). Both were associated in 51% of patients. Vomiting and other digestive signs were observed in the same proportion as described in other series, but dehydration was only seen in three of our patients, probably because of early attention and fluid correction. CONCLUSIONS: 1) the diagnosis of an IEM has often been made after the first consultation at the EU, leading to hospitalization; 2) we should suspect an IEM in patients with neurologic abnormalities (eg, developmental delay, hypotonus or feeding difficulties), especially in those patients with multisystem involvement who appear with acute symptoms; 3) it is of the greatest importance that the appropriate sample collection be made before starting any treatment, because abnormal biochemical data can yield a first approach and allow the definitive diagnosis; and 4) the diagnosis of a patient with an IEM is not based on a single clinical or biochemical data but rather on all abnormal features taken together.

Emergency Service, Hospital↗
PubMed2000

[Imported malaria in children (1993-1998)].

Malaria is the world's most important parasitic infection, accounting for an estimated 300 million cases and 1.5 to 3 million deaths annually. Although it has been eradicated from temperate countries, increasing numbers of travellers visit each year tropical countries, where malaria remains a major cause of morbidity and mortality. Children are particularly at risk from malaria since symptoms can be especially severe and can develop rapidly. Symptoms may differ from those in adults and, as children often have febrile illnesses, malaria could not be suspected. Eleven cases of imported mala-na in children which ages was between 15 month until 13 years, were seen in the Sant Joan de D|u Hospital, Barcelona (Spain) since August 1993 until August 1998. The aetiology was in 7 cases Plasmodium falciparum and in 4 cases Plasmodium vivax, in one case we found also with the P. falciparum some forms of P. malariae. All of them experience fever and anaemia at admission and nine had splenomegaly; the evolution after the treatment was fine. Cases of imported malaria in children are increasing and it is timely to review the prevention and the management.

Adolescent↗
PubMed1999

Acute overdose due to benzydamine.

Benzydamine is a nonsteroidal anti-inflammatory drug, currently available as mouthwash, aerosol, dermal cream, vaginal douche preparation, pills and otic drops. Up to now no cases of poisoning due to this drug have been reported. A 6-year-old girl with an accidental poisoning with benzydamine is described. The episode consisted of hallucinosis without other symptoms and resolved spontaneously in 17 h.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Effect of heat treatment on pulsed laser deposited amorphous calcium phosphate coatings.

Amorphous calcium phosphate coatings were produced by pulsed laser deposition from targets of nonstoichiometric hydroxyapatite (Ca/P = 1.70) at a low substrate temperature of 300 degrees C. They were heated in air at different temperatures: 300, 450, 525 and 650 degrees C. Chemical and structural analyses of these coatings were performed using X-ray diffraction (XRD), FTIR, and SEM, XRD analysis of the as-deposited and heated coatings revealed that their crystallinity improved as heat treatment temperature increased. The main phase was apatitic, with some beta-tricalcium phosphate in the coatings heated at 525 and 600 degrees C. In the apatitic phase there was some carbonate substitution for phosphate and hydroxyl ions at 450 degrees C and almost solely for phosphate at 525 and 600 degrees C as identified by FTIR. This was accompanied by a higher hydroxyl content at 525 and 600 degrees C. At 450 degrees C a texture on the coating surface was observable by SEM that was attributable to a calcium hydroxide and calcite formation by XRD. These phases almost disappeared at 600 degrees C, probably due to a transformation into calcium oxide.

Calcium Phosphates↗
PubMed1998

Physicochemical properties of calcium phosphate coatings produced by pulsed laser deposition at different water vapour pressures.

Calcium phosphate coatings were produced by pulsed laser deposition from targets of non-stoichiometric hydroxyapatite (Ca/P = 1.70) at a substrate temperature of 485 degrees C and different processing pressures of water vapour: 0.15, 0.30, 0.45, 0.60 and 0.80 mbar. The physicochemical properties of these coatings were studied using Fourier-transform IR spectroscopy (FT-IR) and energy dispersive X-ray analysis (EDX). A minimum pressure of water vapour was necessary in order to obtain a crystalline coating, as deduced from the FT-IR spectroscopy of these coatings. This analysis also revealed that when the deposition pressure of water vapour was further increased, the coatings were less crystalline and the content of hydroxyl groups, the carbonate substitution for phosphate, and the Ca/P ratio, as measured by EDX, were lower. These effects can be explained by a combined substitution of carbonate and HPO4(2-) for phosphate, being predominant the carbonate substitution at low pressures and the HPO4(2-) substitution at high pressures.

Calcium Phosphates↗
PubMed1997

[The evaluation of an incentive system for the primary care professionals of Mallorca].

OBJECTIVE: To describe the assessment made by Mallorca's primary care professionals of the economic incentives system set up in 1994 and find their opinions of financial incentives and other motivating mechanisms. DESIGN: A descriptive, crossover study. SETTING: Primary care in Mallorca (INSALUD of the Balearics). PARTICIPANTS: All the health professionals and ancillary workers (554) of Mallorca's 24 Health Centres. MEASUREMENTS AND MAIN RESULTS: A self-filled questionnaire was used as a measuring instrument. There was a 74% reply rate. Their assessment of the incentives system used was that the distribution of the incentives was unjust and a cause of tension. However, expectations as to the amount received had been met to a reasonable extent. Self-management was a stronger motivating force than incentives (48.4% vs 13.6%). CONCLUSIONS: The incentives system used displayed certain faults (in distribution and the work atmosphere generated). However, decentralization was shown to be a powerful motivating force. Monitoring professionals' expectations and the fulfillment of them should be integrated into management habits.

Attitude of Health Personnel↗
PubMed1997

Hydroxyapatite coatings: a comparative study between plasma-spray and pulsed laser deposition techniques.

A comparative study between hydroxyapatite coatings produced by two different techniques, plasma spray (PS) and pulsed-laser deposition (PLD) was carried out. Plasma spray is currently commercially used for coating dental and orthopaedical implant devices, and pulsed-laser deposition (or laser-ablation deposition) gave good results in the field of high critical temperature superconductive thin films, and is being applied to produce calcium phosphate coatings for biomedical purposes. X-ray diffraction was used to control the crystallinity of the coatings, scanning electron microscopy for the surface and cross-sectional morphology, and the pull test to determine the tensile strength of the coatings. This study reveals that the pulsed-laser deposition technique appears to be a very good candidate to replace the plasma spray in many biomedical applications, because it overcomes most of the drawbacks of the plasma spray.

Journal Article↗
PubMed1997

Structural analysis of calcium phosphate coatings produced by pulsed laser deposition at different water-vapour pressures.

Calcium phosphate coatings have been produced by pulsed laser deposition (PLD) at different water-vapour pressures. Rietveld refinement of X-ray diffraction (XRD) data allows us to determine that the structure of these coatings is apatitic with carbonate substitution for phosphate. The carbonate substitution decreases when the chamber pressure is raised, a fact that has been corroborated by Fourier transform-infrared (FT-IR) spectroscopy. Carbonate concentrations between 5 and 17 wt% have been calculated for the crystalline samples. Amorphous coatings are produced at the lowest and highest pressures due to the high carbonate concentration in the first case, and possibly to another type of substitution (Mg(2+), HPO(2-)4, P2O(4-)7) or the inherent kinetics of the PLD process, in the second case.

Journal Article↗
PubMed1996

[Evaluation of the system of direct purchase and distribution of urinary incontinence pads in primary care centers].

OBJECTIVE: To evaluate the impact of the pilot experience of direct purchase and distribution of incontinence diapers in primary health care centres of the Balearic Islands after 10 months of implementation. DESIGN: Comparison of diapers's public expenditures and use during 10 months of pilot experience (9/1/1994-6/30/1995: POSTC) to a same length period prior to pilot experience implementation (11/1/1993-8/31/1994: PREC). SETTING: Primary health care centres of the Balearic Islands (Spain). MEASUREMENTS AND RESULTS: Monthly mean of packages used in the PREC period was 3,246 packages/month, whereas monthly mean of packages used in POSTC period was 4,541 packages/month. It means an increase of 1,295 packages/month. The mean price per package got by public tender was 4,426 ptas., nearly half of mean unit price per package paid through the usual dispensing system of medical prescription (8,583 ptas.), thus producing a saving of 4,157 ptas. per package. A decreasing trend to the monthly mean of diapers use of the PREC period was observed in the last months of the experience. The monthly expenditures in diapers was 27,790 milions ptas. in the PREC period and 21,024 milions ptas. during the POSTC period. CONCLUSIONS: The expected increase in diapers use during the first year of implementation of this measure was 34.86%. Of this increase, 70.5% is attributed to development of stock in centres and the undergoing trend of diapers demand increase observed throughout the country.

Costs and Cost Analysis↗
PubMed1990

[The pharmaceutical prescription: a comparison between the old and the new model of primary health care].

The possible influence of the model of primary health care (PHC), the educational background of the physician and the type of contract on pharmaceutical prescription were evaluated. The information was obtained from a sample of 1799 prescriptions, which were representative of the overall prescription of the PHC physicians from the Health Service of Palma de Mallorca. The health center physicians (HC) prescribed less expensive drugs than the classical clinic physicians (CC). The mean prize for HC was 498.98, with SD 418.97, and for CC it was 589.65 with SD 750.25. This difference was significant (p less than 0.0001). There were other significant differences, such as a smaller use of preparations with fixed drug associations (p less than 0.01) and parenteral administration (p less than 0.05) by HC. There were no significant differences in the prescription of cerebral and peripheral vasodilators and drugs for the digestive tract and metabolism considered as doubtful indications.

Drug Prescriptions↗
PubMed1988

[Induction of cellulases and xylanases in Aureobasidium pullulans].

The specificity or induction of wood-degrading enzymes using series of mono, di or polysaccharides as carbon source for the yeasts Geotrichum candidum and Trychosporon penicillatum and the yeast-like organism Aureobadidium pullulans were studied. The strain A. pullulans was the only one that when xylan or "steam exploded wood" were used as carbon source all the enzymes tested were found. This strain was unable to grow on carboxymethyl or Avicel cellulose. D-xylose was the nutritional inducer of beta-xylosidase and beta-xylanase but D-glucuronic acid induced CMCase activity and beta-glucosidase was produced with every carbon source. The 1,4 beta-xylobiose was not an inducer of beta-xylanase but with the structural 1,2-beta- and 1,3-beta-xylobiose isomers high levels of this enzyme were obtained.

Carbon↗