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Biomedical subjects

S Martín

Publications and source records attributed to S Martín.

At least 19 recordsLinked to original sources

Metal corrosion in bones implanted with Zinalco--a SAXS and NMR study.

The composition and morphology of bones implanted with stainless steel (316L-SS) and a metal alloy made of zinc, aluminum, and copper (Zinalco) are compared. Small-angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR) results show that with time Zinalco is corroded and zinc, aluminum, and copper diffuse into the osseous tissue, promoting nonhomogeneous bone. Instead, 316L-SS does not incorporate into bone, and the bone recovers homogeneously at a lower speed.

Aluminum↗

IgE reactivity to latex allergens among sensitized healthcare workers before and after immunotherapy with latex.

BACKGROUND: New IgE sensitizations to proteins in allergen extracts have been shown to occur during allergen-specific immunotherapy (IT). METHODS: Twenty-four healthcare workers (HCWs) -- patients included in a latex IT study -- were analysed, 16 in active treatment and eight in placebo. Sera were obtained at baseline and after 6 months of IT and analysed with immunoblotting and CAP System with eight single recombinant latex allergens (rHev b 1, 3, 5, 6.01, 8, 9, 10, 11, and a mix of rHev b1, 5, 6.01 and 8). RESULTS: After IT with latex, three patients in the active treatment group had new IgE sensitizations, one to Hev b 5, one to Hev b 11 and another to Hev b 6.01. No other significant variation in mean of specific IgE to latex or recombinant allergens were observed in patients who received placebo or active treatment. A significant (P = 0.012) negative correlation (-0.72) was observed between maximal tolerated dose and specific IgE to Hev b 6.01 at baseline. After IT, immunoblot analysis demonstrated a significant increase in IgE binding in a band of approximately 22 kDa (P = 0.032) that may correspond to Hev b 6.01. New or more intense bands appeared in seven patients of the active group, while in three subjects a reduction was observed. CONCLUSIONS: Hev b 6.01 seems to be the most relevant latex allergen in HCWs. New or more intense IgE binding to latex allergenic components occurs during latex immunotherapy. However, the levels of specific IgE against these new components are low and do not seem to have clinical relevance.

Allergens↗

Influence of climatic and management factors on Eimeria infections in goats from semi-arid zones.

A survey of Eimeria infections was performed in dairy goats and kids (<6 months old) of six farms from a dry desert area of Gran Canaria Island (Spain). The number of oocysts per gram of faeces (OPG) was determined by a modified McMaster technique over a total of 2,616 individual faecal samples taken from the rectum in monthly intervals. Eimeria oocysts were found in 96.1% of the samples with OPG ranging from 1 x 10(2) to 1.4 x 10(6). Kid goats had significantly (P < 0.001) higher OPG counts (46,496 +/- 5,228) than dairy females (2,225 +/- 287). Eight Eimeria species were identified, with Eimeria ninakohlyakimovae (30.0%), Eimeria arloingi (28.6%) and Eimeria alijevi (20.5%) being the most frequent species followed by Eimeria caprina (9.1%), Eimeria christenseni (4.5%), Eimeria jolchijevi (3.4%), Eimeria caprovina (3.2%) and Eimeria hirci (0.7%). Although significant differences were observed among goat groups and herds, the eight species were present in the six farms in both dairy goats and kids. The intensity of oocysts shedding was related to some factors such as the size of the herd and was further influenced by the prevailing climatic conditions of the area. The highest OPG counts were recorded during the hot season in dairy goats and close to weaning time in kids reared in small farms having no prophylactic treatments against eimeriosis.

Animals↗

[Possibility of cauda equina nerve root damage from lumbar punctures performed with 25-gauge Quincke and Whitacre needles].

OBJECTIVE: To assess the possibility of puncturing nerve roots in the cauda equina with spinal needles with different point designs and to quantify the number of axons affected. MATERIAL AND METHODS: We performed in vitro punctures of human nerve roots taken from 3 fresh cadavers. Twenty punctures were performed with 25-gauge Whitacre needles and 40 with 25-gauge Quincke needles; half the Quincke needle punctures were carried out with the point perpendicular to the root and the other half with the point parallel to it. The samples were studied by optical and scanning electron microscopy. The possibility of finding the needle orifece inserted inside the nerve was assessed. On a photographic montage, we counted the number of axons during a hypothetical nerve puncture. RESULTS: Nerve roots used in this study were between 1 and 2.3 mm thick, allowing the needle to penetrate the root in the 52 samples studied. The needle orifice was never fully located inside the nerve in any of the samples. The numbers of myelinized axons affected during nerve punctures 0.2 mm deep were 95, 154, and 81 for Whitacre needles, Quincke needles with the point held perpendicular, or the same needle type held parallel, respectively. During punctures 0.5 mm deep, 472, 602, and 279 were affected for each puncture group, respectively. The differences in all cases were statistically significant. CONCLUSIONS: It is possible to achieve intraneural puncture with 25-gauge needles. However, full intraneural placement of the orifice of the needle is unlikely. In case of nerve trauma, the damage could be greater if puncture is carried out with a Quincke needle with the point inserted perpendicular to the nerve root.

Cauda Equina↗

Double-blind, placebo-controlled study of immunotherapy with Parietaria judaica: clinical efficacy and tolerance.

Allergy to Parietaria causes significant morbidity in most Mediterranean areas. The aim of this study is to investigate the efficacy and tolerance of Parietaria depot extract at 25 BU/mL (1.5 microg/mL Par j 1). We performed a multicenter double-blind, placebo-controlled study in rhinitic patients with/without asthma, sensitized to Parietaria. 42 patients followed 20-month immunotherapy. Clinical efficacy was based on symptom and medication scores and the percentage of healthy days (days without symptoms or medication). Severity of asthma/rhinitis scales, visual analogue scale, evaluation of the treatment by doctors and patients, immediate and delayed cutaneous response and quality of life questionnaires were also studied. The active group showed a sustained decrease in symptoms (p = 0.008), medication (p = 0.009) and both (p = 0.001), and an increase in healthy days (p = 0.001) throughout the study, with a threefold increase of healthy days and almost a three time reduction in medication only after one year of treatment. Asthma and rhinitis severity scales also decreased after immunotherapy, and blinded clinical evaluation by physicians confirmed efficacy in 85% and 77% of the active patients. Patient's self-evaluation returned similar results. None of these changes were observed with placebo. Immediate cutaneous response was significantly reduced at the maintenance phase in the active group and remained reduced throughout the study. Late-phase response after intradermal testing also showed a statistical decrease in actively treated patients. Immunotherapy was well tolerated and every systemic reaction reported was mild. In conclusion, immunotherapy with Parietaria 25 BU/mL is an effective and safe treatment for patients with respiratory allergies.

Adolescent↗

The complete nucleotide sequence of a Spanish isolate of Citrus psorosis virus: comparative analysis with other ophioviruses.

The complete genomic sequence (11278 nt) of Citrus psorosis virus (CPsV), isolate P-121 from Spain, was determined and compared with those from isolate CPV-4 and from other ophioviruses. The three RNAs of P-121 had similar size and identical organization as those of CPV-4. The 24K and the RdRp proteins were potentially encoded in the viral complementary (vc) strand of RNA 1, the 54K protein potentially encoded in vcRNA 2 and the coat protein encoded in vcRNA 3. These four proteins from P-121 and CPV-4 had 87, 92, 93 and 94% amino acid identity, respectively, but only 22, 38, 25 and 33% identity with their homologous proteins from Mirafiori lettuce big vein virus (MLBVV), the only other ophiovirus completely sequenced. Biological and genetic differences between CPsV and MLBVV (and the other ophioviruses), would support their future allocation in different genera within a tentative family Ophioviridae.

Base Sequence↗

Dura-arachnoid lesions produced by 22 gauge Quincke spinal needles during a lumbar puncture.

AIMS: The dural and arachnoid hole caused by lumbar puncture needles is a determining factor in triggering headaches. The aim of this study is to assess the dimensions and morphological features of the dura mater and arachnoids when they are punctured by a 22 gauge Quincke needle having its bevel either in the parallel or in the transverse position. METHODS: Fifty punctures were made with 22 gauge Quincke needles in the dural sac of four fresh cadavers using an "in vitro" model especially designed for this purpose. The punctures were performed by needles with bevels parallel or perpendicular to the spinal axis and studied under scanning electron microscopy. RESULTS: Thirty five of the 50 punctures done by Quincke needles (19 in the external surface and 16 in the internal) were used for evaluation. When the needle was inserted with its bevel parallel to the axis of the dural sac (17 of 35), the size of the dura-arachnoid lesion was 0.032 mm(2) in the epidural surface and 0.037 mm(2) in the subarachnoid surface of the dural sac. When the needle's bevel was perpendicular to the axis (18 of 35) the measurement of the lesion size was 0.042 mm(2) for the external surface and 0.033 mm(2) for the internal. There were no statistical significant differences between these results. CONCLUSIONS: It is believed that the reported lower frequency of postdural puncture headache when the needle is inserted parallel to the cord axis should be explained by some other factors besides the size of the dura-arachnoid injury.

Arachnoid↗

Diversity of moderately halophilic bacteria producing extracellular hydrolytic enzymes.

AIMS: The aim of this study was to determine the diversity of moderately halophilic bacteria with hydrolase activities. METHODS AND RESULTS: Screening bacteria from different hypersaline environments in South Spain led to the isolation of a total of 122 moderately halophilic bacteria able to produce different hydrolases (amylases, DNases, lipases, proteases and pullulanases). These bacteria are able to grow optimally in media with 5-15% salts and in most cases up to 20-25% salts. In contrast to strains belonging to previously described species, that showed very little hydrolase activities, environmental isolates produced a great variety of hydrolases. These strains were identified as members of the genera: Salinivibrio (55 strains), Halomonas (25 strains), Chromohalobacter (two strains), Bacillus-Salibacillus (29 strains), Salinicoccus (two strains) and Marinococcus (one strain), as well as eight non-identified isolates. CONCLUSIONS: Moderately halophilic bacteria are a source of hydrolytic enzymes such as amylases, DNases, lipases, proteases and pullulanases. SIGNIFICANCE AND IMPACT OF THE STUDY: Although most culture collection strains are not able to produce hydrolases, it has been shown that environmental isolates can produce these potentially biotechnological important enzymes.

Amylases↗

Marinobacter lipolyticus sp. nov., a novel moderate halophile with lipolytic activity.

In the course of a screening programme in hypersaline habitats of southern Spain to isolate halophilic bacteria that are able to produce different extracellular enzymes, a novel, moderately halophilic bacterium (strain SM19(T)) that displays lipolytic activity has been isolated and characterized. Strain SM19(T) is a Gram-negative rod that grows optimally in culture media that contain 7.5 % NaCl. The DNA G+C content was 57.0 mol%. According to phenotypic and genotypic data, this strain was assigned to the genus MARINOBACTER: However, 16S rDNA sequence similarity between strain SM19(T) and species of the genus Marinobacter was <96.7 %; this value is sufficiently low to propose its designation as a novel species. In addition, DNA-DNA hybridization with reference strains of close phylogenetic relatives was between 11 and 19 %. On the basis of these data, the inclusion of strain SM19(T) in the genus Marinobacter as a novel species is proposed, with the name Marinobacter lipolyticus sp. nov. The type strain of the novel species is SM19(T) (=DSM 15157(T)=NCIMB 13907(T)=CIP 107627(T)=CCM 7048(T)).

Alteromonadaceae↗

High efficacy and absence of severe systemic reactions after venom immunotherapy.

The efficacy of immunotherapy with venom (ITV) is supported by many studies. However, the key point for ITV is the balance between safety and efficacy, as concern for adverse events may restrict its use, and limit the administration of this treatment to the hospital, exclusively. The objectives of the present study were, first, to analyze the characteristics and incidence of ITV-related adverse events and to determine whether the administration of this treatment exclusively in hospitals is justified, and second, to assess the efficacy of a semi-rush dosage schedule, which is being used in our department. We analyzed the data of 241 patients with known allergy to hymenoptera venom (208 sensitive to Apis mellifera and 33 to Vespula spp.), who were treated with ITV (Pharmalgen, ALK-ABELLO) for an average period of 32 months. The initial treatment was performed at the Allergy Department, administering nine increasing doses of the venom once or twice a week. Maintenance treatment, whenever possible, was performed at primary care centers (PCCs). In this study, 95 patients (39%) were referred to their corresponding PCC. A total of 3697 doses were administered, and 37 systemic reactions (SR) and 37 local reactions (LR) were recorded; the overall frequency of occurrence of adverse events was 1.97%, 1% corresponding to SR, and 1% related to LR. The severity of most of SR was mild and the response to treatment with oral antihistamines and corticoids was good. Administration of adrenaline was required in 14 cases. Regarding the maintenance treatment administered at PCCs, only two adverse events were recorded, one case of vaso-vagal symptomatology and one case of urticaria-like reaction two hours after the administration. Eighty-four cases of spontaneous field stings, corresponding to 58 patients, were reported; in 82 cases (97.6%) the reaction was less severe than that experienced before the administration of ITV. The severity of the other two reactions was the same as previously recorded, though they occurred in patients during the build-up phase of the treatment. In any case, a reaction with a higher grade of severity was recorded. The dosage schedule administered is efficient, the frequency of occurrence of adverse events is low, their intensity is generally mild, and minimum medication is required to control them (antihistamines, corticosteroids). Taking into account the tolerance observed during the maintenance treatment, we consider that its administration at PCCs is appropriate.

Adolescent↗

The optimal immunotherapy cluster schedule in clinical practice.

The efficacy of injective immunotherapy is no longer a matter of debate, but concerns about its safety and compliance problems (because of the number of visits required for the build-up phase) are limiting factors for wider usage. Different schedules have, therefore, been used in clinical trials with the aim of improving both safety and compliance. We investigated the effects on tolerance of modifications to the starting allergenic dose, of the pharmaceutical presentation of the allergen (aqueous or depot), of the change of the number and volume of the daily administrations through progressive adjustments of the so-called clustered schedule. We took the rate of local and/or systemic side effects as the primary criterion, and were able to gradually reduce the rate of systemic reactions per dose and per patient from 4.1% and 65% to 0.3% and 2.6%, respectively, through four progressive modifications of the starting schedule. According to our data, it is possible to reach the maintenance dose in only four visits with 2 administrations per visit. This was achieved either by switching from aqueous to depot extracts or by using depot extracts from the beginning. These results have been obtained without any kind of premedication and with a wide range of allergens, including mites, epithelia, pollens, and honeybee venom. We have shown that the number of injections administered following the conventional schedule could be reduced by 75%, shortening the build-up phase by 38.5%, without increasing the rate of side effects. We think clustered schedules could lead to a better compliance and to a broader use of injective immunotherapy.

Adolescent↗

Liposome-entrapped D. pteronyssinus vaccination in mild asthma patients: effect of 1-year double-blind, placebo-controlled trial on inflammation, bronchial hyperresponsiveness and immediate and late bronchial responses to the allergen.

BACKGROUND: Allergen vaccination is effective in mite-allergic asthma. Liposomes are immunological adjuvants that can act as allergen carriers. OBJECTIVE: To evaluate the immunological and functional effects of a liposome-entrapped D. pteronyssinus vaccine on mite monosensitive, mild asthma patients. METHODS: A double-blind, placebo-controlled trial was conducted on 26 asthma patients who randomly received vaccination or placebo for 1 year. The levels of exposure to Der p 1 allergen were constant during the study. Allergen bronchial challenge was made at the beginning (T0) and after 1 year of treatment (T12). The day before and 24 h after the allergen provocation, patients were challenged with methacholine (Mth) (until FEV1 fell by 40%) and blood and sputum samples were obtained. Dose-response curves to Mth were evaluated in terms of Mth-PD20 (dose of Mth that induced 20% drop in FEV1), slope (Mth-DRS) and level of plateau. Blood and sputum eosinophils and serum levels of eosinophil cationic protein (ECP) and intercellular adhesion molecule-1 (ICAM-1) were measured. RESULTS: Groups were comparable at the start of the trial. At TI2, previous to the allergen challenge, the active group showed higher values of both FEV1 and Mth-PD20 and lower values of Mth-DRS. The number of patients presenting a level of plateau increased in the active group (from two to four) and decreased in the placebo group (from two to one). At T12, before the allergen challenge, serum ECP levels increased in the placebo group and blood eosinophils showed a trend towards lower numbers in the active one. The immediate response and the changes in Mth-DRS values, sputum eosinophils and serum ECP levels following the allergen challenge were attenuated in the active group. CONCLUSION: Liposome-entrapped D. Pteronyssinus vaccination: (i) protects mild asthma patients from the worsening of asthma due to sustained mite exposure; and (ii) reduces the functional and inflammatory changes induced by allergen bronchial provocation.

Adult↗

Immunotherapy with an extract of Olea europaea quantified in mass units. Evaluation of the safety and efficacy after one year of treatment.

Sensitization to olive pollen is a frequent cause of rhinoconjunctivitis (RC) and bronchial asthma (BA) in the region of Jaén (southern Spain), where this allergen reaches atmospheric levels of almost 7000 grains/m3 during pollen season (May and June) and produces high morbidity. Specific immunotherapy (SIT) has proven very efficient in allergic RC and BA caused by grass pollen. Considering the availability of a biologically standardized extract of Olea europaea, with its major allergen quantified in mass units, we decided to investigate SIT with this extract in a group of rhinitic and/or asthmatic patients monosensitized to olive. We studied tolerance, safety, and efficacy by comparison of the active group (subjected to SIT) with a control group that did not receive SIT. A hyposensitizing dose of Olea europaea extract was administered preseasonally, establishing a maintenance dose 3.8 times higher than those administered in conventional treatments. Eighty-three percent of the patients reached the proposed maximal dose of 75 BU, equivalent to 45 micrograms Ole e 1, with a rate of 0.8% of systemic reactions. A significant decrease in cutaneous (p < 0.001) and bronchial (p < 0.001) reactivity was observed in the active group, but not in the control group. Also, a decrease in specific IgE and an increase in IgG1 and IgG4 were found in the group of patients treated with SIT. Regarding clinical evolution, the active group, but not the control group, experienced a clear statistically significant improvement both in nasal (p < 0.05) and bronchial (p < 0.05) symptoms, in addition to a significant decrease in the consumption of antihistamines (p < 0.05) and beta 2-agonists (p < 0.01). In conclusion, SIT with olive extract proved to be safe and efficacious for the treatment of asthma and rhinitis caused by this allergen.

Adolescent↗

Weak M(II)-azide-4,4'-bipy ferromagnets based on unusual diamondoid (M = Mn) and 2D arrays (M = Co, Ni).

Four compounds of general formula [M(4,4'bipy)(N(3))2](n) (M = Mn (1), Zn (2), Co (3), Ni (4)) have been synthesized and magnetostructurally characterized by means of X-ray diffraction analysis, IR and ESR spectroscopies, and measurements of the magnetic susceptibility and magnetization. Compound 1 (C(10)H(8)N(8)Mn) crystallizes in the tetragonal P4(3)2(1)2 space group, Z = 4, with a = 8.229(2), b = 8.229(2), and c = 16.915(2) A. It exhibits an acentric 3D structure where Mn(II) ions are linked through EE-azide groups resulting in a diamondoid network. The 4,4'bipy ligands are coordinated on the axial positions of the octahedral spheres reinforcing the intermetallic connections. Weak ferromagnetism arising from spin canting is observed for compound 1. Compounds 2, 3, and 4 are proposed to be isomorphous and would consist of a 2D array where alternating EO + EE/EO + EE/EO + EO azide-chains are linked by 4,4'bipy ligands resulting in pi-pi stacked pyridyl-columns. The azido ligand dispositions in compounds 3 and 4 make possible systems of type -AF-AF-F-, which would give rise to a topological ferromagnetic behavior.

Journal Article↗

Structural analysis and magnetic properties of the 1D and 3D compounds [Mn(dca)2nbipym] (M = Mn, Cu; dca = dicyanamide; bipym = bipyrimidine; n = 1,2).

Compounds [Mn(dca)2bipym] (1), [Cu2(dca)4bipym] (2), and [Mn2(dca)4bipym] (3) have been synthesized and structural (2, 3) and magnetically characterized. Compound 1 is isomorphous with [Mn(dca)2bipy]. Compound 2 crystallizes in the monoclinic P2(1)/c space group, Z = 4, with a = 7.5609(9), b = 11.477(42), and c = 11.792(2) A and beta = 106.565(6) degrees. Compound 3 crystallizes in the monoclinic system, space group P2(1)/n, with a = 7.396(3) A, b = 11.498(7) A, and c = 12.349(9) A and beta = 106.61(5) degrees. While compound 1 is one-dimensional, with the manganese(II) ions bridged by double mu1,5-dicyanamide ligands, the structural arrangement in compounds 2 and 3 is three-dimensional based on ladder-like moieties. These units, whose steps are bipym groups, extend through mu1,5-dca bridges and are connected to another four on the plane perpendicular to the extension of the ladders to form the 3D arrangement. Magnetic susceptibility measurements show antiferromagnetic couplings in all cases, increasing for 1, 3, and 2, respectively.

Journal Article↗

Mathematical modelling of landfill gas migration in MSW sanitary landfills.

The laws that govern the displacement of landfill gas in a sanitary landfill are analysed. Subsequently, a 2-D finite difference flow model of a fluid in a steady state in a porous medium with infinite sources of landfill gas is proposed. The fact that landfill gas is continuously generated throughout the entire mass of the landfill differentiates this model from others extensively described in the literature and used in a variety of different applications, such as oil recovery, groundwater flow, etc. Preliminary results are then presented of the application of the model. Finally, the results obtained employing data from the literature and experimental assays carried out at the La Zoreda sanitary landfill (Asturias, Spain) are discussed and future lines of research are proposed.

Air Movements↗