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Biomedical subjects

M T Martínez

Publications and source records attributed to M T Martínez.

17 recordsLinked to original sources
PubMed2006

Plant regeneration through somatic embryogenesis from tissues of mature oak trees: true-to-type conformity of plantlets by RAPD analysis.

Somatic embryogenesis was induced in expanding leaf explants excised from epicormic shoots forced from branch segments taken at four different times of year from a mature oak (Quercus robur L.). Branch segments 2-4 cm in diameter produced most shoots when collected in March. Somatic embryos were induced on explants derived from branches of all collection dates, although collection in November seemed to afford the best results. Germination and conversion ability of embryos of embryogenic lines derived from six oak trees depended heavily on genotype, conversion rates ranging from 0 to 70%. RAPD analyses found no evidence of genetic variation either within or between the embryogenic lines established from three of these trees, or between these lines and the trees of origin, or between somatic embryo derived plantlets and the trees of origin. The embryogenic system used in this study appears to be suitable for true-to-type clonal propagation of mature oak genotypes.

Culture Media↗
PubMed2005

[Vascular access guidelines for hemodialysis].

Quality of vascular access (VA) has a remarkable influence in hemodialysis patients outcomes. Dysfunction of VA represents a capital cause of morbi-mortality of these patients as well an increase in economical. Spanish Society of Neprhology, aware of the problem, has decided to carry out a revision of the issue with the aim of providing help in comprehensión and treatment related with VA problems, and achieving an homogenization of practices in three mayor aspects: to increase arteriovenous fistula utilization as first vascular access, to increment vascular access monitoring practice and rationalise central catheters use. We present a consensus document elaborated by a multidisciplinar group composed by nephrologists, vascular surgeons, interventional radiologysts, infectious diseases specialists and nephrological nurses. Along six chapters that cover patient education, creation of VA, care, monitoring, complications and central catheters, we present the state of the art and propose guidelines for the best practice, according different evidence based degrees, with the intention to provide help at the professionals in order to make aproppiate decissions. Several quality standars are also included.

Arteriovenous Shunt, Surgical↗
PubMed2003

Cryopreservation of embryogenic cultures of Quercus robur using desiccation and vitrification procedures.

Oak embryogenic cultures are generally maintained by repetitive embryogenesis. To facilitate management of embryogenic lines and limit the risks of somaclonal variation and contamination a cryopreservation protocol should be developed. In this work we investigated the ability of several pre-treatments to enable 4-6mg clumps (1.0-1.5mm) of globular-heart stage somatic embryos of Quercus robur to withstand freezing in liquid nitrogen. In the best of the two embryogenic culture lines used, 56% of clumps resumed embryogenesis after cooling when they had been pre-treated by successive pre-culture on 0.3 and 0.7M sucrose supplemented media followed by desiccation in the air flow of a laminar flow cabinet to water contents of 24-34%. In both lines, embryogenesis resumption rates of about 70% were achieved by pre-culture on 0.3M sucrose medium followed by application of a vitrification solution (PVS2) for 60-90min prior to rapid plunging in liquid nitrogen.

Cell Line↗
PubMed2002

Microwave single walled carbon nanotubes purification.

A new single walled carbon nanotubes (SWCNTs) purification procedure has been developed; it consists in a combination of air treatment and acid microwave digestion leading to a high purity SWCNTs material; the procedure reaches high metal removal percentages and the operation time is drastically reduced compared to conventional acid reflux treatments.

Journal Article↗
PubMed1998

Usefulness of a national registry of alpha-1-antitrypsin deficiency. The Spanish experience.

Severe alpha-1-antitrypsin (AAT) deficiency, phenotype Pi ZZ, is a rare condition with an estimated prevalence of 1/4500 individuals in Spain. Given this low prevalence, it seems useful to accumulate all the information derived from the care of these patients. In this context, the Spanish Registry of patients with AAT deficiency was founded in 1993; its main objectives were to establish guidelines adapted to our country for the treatment and management of AAT-deficient patients, offer expert support to physicians all over the country treating these patients, and provide technical support on the determination of Pi phenotyping and genotyping of individuals suspected of being AAT-deficient. From 1993 to January 1998 the number of enrollees increased from 48 to 223, of which 216 were Pi ZZ. Seventy-three per cent were male and only 31.5% were never smokers, mean age was 46 years (SD = 13 years) and mean FEV1 53% predicted (SD = 31%). 83% were index cases who, compared with non-index cases, were older (49 +/- 11 vs. 35 +/- 13 years, P < 0.001), more likely to have a smoking history (85% vs. 47%, P < 0.01) and displayed more severe impairment in pulmonary function (FEV1% = 40% +/- 19% vs. 96% +/- 23%, P < 0.001). Augmentation therapy was administered to 129 patients (58%). Treated patients had more severe impairment in pulmonary function than the untreated (FEV1% = 40% +/- 21% vs. 72% +/- 32%, P < 0.001) and were more likely to be index cases (81% vs. 43%, P < 0.001). Characteristics of the patients included are similar to those described for other Registries. The Registry has extended knowledge of the disease throughout the country and has established local guidelines for treatment and follow-up. It may be a valid database for future co-operation in international initiatives.

Adult↗
PubMed1996

HLA-DR, DQ and anti-GAD antibodies in first degree relatives of type I diabetes mellitus.

The differential antibody response to glutamic acid decarboxylase (anti-GAD) and to islet cell cytoplasm (ICA) according to HLA-DR and DQ genotypes were examined in 28 Spanish patients with Type I diabetes mellitus (11.1 +/- 10.4 year diabetes duration) and their 41 first degree non-diabetic relatives. Anti-GAD was detected by radioimmunoprecipitation and ICA by indirect immunofluorescence and HLA-DR/DQ alleles were assigned by PCR and sequence specific oligonucleotide probes. The frequency in patients of positivity for ICA was 7.1% and of anti-GAD+ 64.3%, and in relatives, the frequency of ICA+ was 4.9%, and anti-GAD+ 9.8%. Concurrent positivity for ICA and anti-GAD existed in only one patient, and in none of the relatives. We confirm for a Spanish population the high frequency of risk genotypes for Type I, involving DR3, DR4 and DQB1*0302 (DQ8) which were present in 26 of 28 (93%) patients and 32 of 41 (78%) relatives. The most frequent genotypes were DR3/DQB1*0201/DQA1*0501-DR4/DQB1*0302/DQA1*0301( 9 patients, 32%; 6 relatives, 15%), DR3/DQB1*0201/ DQA1*0501-DR3/DQB1*0201/DQA1*0501 (5 patients, 18%; 7 relatives, 17%) and DE3/DQB1*0201/DQA1*0501-DR1/ DQB1*0501/DQA1*0101(5 patients, 18%; 1 relative, 2%). Positivity for anti-GAD or for ICA did not correlate with gender, or age at onset or duration of DM. The distribution of high risk HLA genotypes were similar regardless the anti-GAD or anti-ICA status either in patients or in their relatives.

Adolescent↗
PubMed1994

[Lipoprotein (a) and other risk factors in Chilean children with type I diabetes mellitus].

AIMS: To study serum Lp(a) levels and other metabolic cardiovascular risk factors in children with type I diabetes mellitus (DM) in comparison with sex and age matched nondiabetic children. To determine the influence of diabetes control on serum lipoprotein (a) concentrations. DESIGN: Transversal observational study. TARGET POPULATION: diabetic group: 70 type I DM children without microalbuminuria and no macro-microvascular nor neurological complications, aged from 8 to 15 years; 30 boys, 40 girls. Mean duration of type I DM was 8 +/- 4 years. Non diabetic group: composed by 123 healthy children with no family history of DM, aged from 8 to 15 years, 53 boys, 70 girls. METHODS: The lipids profile include: total cholesterol (TC) and triglyceride (TG), cholesterol high-density lipoproteins (C-HDL) cholesterol very-low-density lipoproteins (C-LDL) and cholesterol low-density lipoproteins (C-LDL). ApoAI, APOAII and ApoB, Lp(a) and fructosamine. RESULTS: Fructosamine concentration in diabetic children was 340 +/- 108 uM/1 in 240 +/- 25 uM/l nondiabetic children. Lp(a) serum levels did not significantly differ among both groups 17 +/- 16 mg/dl in diabetics 19 +/- 18 mg/dl in controls. Multivariate analysis showed that in the diabetic children the worsening of metabolic control as reflected by fructosamine, was positively correlated with the increase in total Lp(a) serum concentration. CONCLUSIONS: In children aged 8-15 years with uncomplicated IDDM lasting less than 15 years duration, Lp(a) serum levels are positively correlated with the poorest metabolic control.

Adolescent↗
PubMed1994

[Lipoprotein (a), atherosclerosis, and diabetes mellitus].

Diabetes mellitus is associated with a three to fourfold increased risk for coronary artery disease and diabetic patients frequently have an abnormal plasma lipid profile. Lately, lipoprotein (a) has received attention as an important independent risk factor for cardiovascular disease. This lipoprotein is elevated in patients with type II diabetes mellitus and there may be an association between the metabolic control of these subjects and its levels. In this review the main features of lipoprotein (a) and its relationship to the fibrinolytic system and atherosclerosis are reviewed.

Arteriosclerosis↗
PubMed1994

[HLA and insulin-dependent diabetes mellitus].

The propensity of an individual to develop type I (insulin dependent) diabetes mellitus is directly related to specific HLA class II proteins, specially those from DR and DQ regions. Genetic susceptibility to insulin dependent diabetes arises from a preestablished conformation of alpha and beta chains of DQ and beta chain of DR. Since the classic demonstration by McDevitt and colleagues that DQ beta chain aspartate at position 57 was protective against the development of the disease, many populations have been surveyed to study the association between the incidence Type I diabetes and determined frequencies of DR and DQ haplotypes. The association between these markers and susceptibility to Type I diabetes is well established in caucasians at the present time. However, little information is available for Latin American populations, that share a mixture of european, african and native genes. Our group is studying genetic markers of three Latin American populations (Argentina, Perú and Chile) and their possible association to the different incidence of Type I diabetes mellitus in each country.

Diabetes Mellitus, Type 1↗