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Biomedical subjects

P Martín

Publications and source records attributed to P Martín.

At least 19 recordsLinked to original sources
PubMed2006

Allele frequencies of six miniSTR loci (D10S1248, D14S1434, D22S1045, D4S2364, D2S441 and D1S1677) in a Spanish population.

Allele frequencies and forensic parameters for six miniSTR autosomal loci (D10S1248, D14S1434, D22S1045, D4S2364, D2S441 and D1S1677) were obtained from a sample of 264 unrelated individuals from Spain. No significant deviations from Hardy-Weinberg expectations were found. Due to the small PCR products (<125 bp), the use of these non-CODIS (NC) miniSTRs can increase the probability that a degraded sample can be typed. Additionally, these systems can be used in routine paternity analyses where more markers are needed to increase the power of exclusion or in complex paternity cases (e.g. involving closely related individuals).

DNA Fingerprinting↗
PubMed2006

FGF2 plays a key role in embryonic cerebrospinal fluid trophic properties over chick embryo neuroepithelial stem cells.

During early stages of brain development, neuroepithelial stem cells undergo intense proliferation as neurogenesis begins. Fibroblast growth factor 2 (FGF2) has been involved in the regulation of these processes, and although it has been suggested that they work in an autocrine-paracrine mode, there is no general agreement on this because the behavior of neuroepithelial cells is not self-sufficient in explants cultured in vitro. In this work, we show that during early stages of development in chick embryos there is another source of FGF2, besides that of the neuroepithelium, which affects the brain primordium, since the cerebrospinal fluid (E-CSF) contains several isoforms of this factor. We also demonstrate, both in vitro and in vivo, that the FGF2 from the E-CSF has an effect on the regulation of neuroepithelial cell behavior, including cell proliferation and neurogenesis. In order to clarify putative sources of FGF2 in embryonic tissues, we detected by in situ hybridization high levels of mRNA expression in notochord, mesonephros and hepatic primordia, and low levels in brain neuroectoderm, corroborated by semiquantitative PCR analysis. Furthermore, we show that the notochord segregates several FGF2 isoforms which modify the behavior of the neuroepithelial cells in vitro. In addition, we show that the FGF2 ligand is present in the embryonic serum; and, by means of labeled FGF2, we prove that this factor passes via the neuroepithelium from the embryonic serum to the E-CSF in vivo. Considering all these results, we propose that, in chick embryos, the behavior of brain neuroepithelial stem cells at the earliest stages of development is influenced by the action of the FGF2 contained within the E-CSF which could have an extraneural origin, thus suggesting a new and complementary way of regulating brain development.

Animals↗
PubMed2006

[Kidney transplant].

The kidney transplant is the therapy of choice for the majority of the causes of chronic terminal kidney insufficiency, because it improves the quality of life and survival in comparison with dialysis. A kidney transplant from a live donor is an excellent alternative for the young patient in a state of pre-dialysis because it offers the best results. Immunosuppressive treatment must be individualised, seeking immunosuppressive synergy and the best safety profile, and must be adapted to the different stages of the kidney transplant. In the follow-up to the kidney transplant, cardiovascular risk factors and tumours must be especially taken into account, given that the death of the patient with a working graft is the second cause of loss of the graft following the first year of the transplant. The altered function of the graft is a factor of independent cardiovascular mortality that will require follow-up and the control of all its complications to postpone the entrance in dialysis.

Acute Disease↗
PubMed2005

A case of double alleles at three Y-STR loci: forensic implications.

In a genetic study of unrelated donors from Bahia (Brazil), one sample contained a 16 Y-STR haplotype with double peaks at three loci: DYS389 II, DYS437 and DYS439. The son of the subject had the same haplotype as found in the father. This profile was compared with a similar case found in a paternity case investigation in Madrid (Spain) and a match was found for the full 16 Y-STR haplotype. Because these three loci are located within the AZFa segment, these results are in accordance with duplication of the AZFa region that includes also other Y-STRs currently used in forensic investigation, for example DYS389I and DYS438. This case attracts our attention in the forensic interpretation of Y-haplotype profiles, because multiple alleles at various loci do not indicate forcibly that the sample under analysis is a mixture.

Brazil↗
PubMed2005

Mutation rates at Y chromosome specific microsatellites.

A collaborative work was carried out by the Spanish and Portuguese ISFG Working Group (GEP-ISFG) to estimate Y-STR mutation rates. Seventeen Y chromosome STR loci (DYS19, DYS385, DYS389I and II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS460, DYS461, DYS635 [GATA C4], GATA H4, and GATA A10) were analyzed in a sample of 3,026 father/son pairs. Among 27,029 allele transfers, 54 mutations were observed, with an overall mutation rate across the 17 loci of 1.998 x 10(-3) (95% CI, 1.501 x 10(-3) to 2.606 x 10(-3)). With just one exception, all of the mutations were single-step, and they were observed only once per gametogenesis. Repeat gains were more frequent than losses, longer alleles were found to be more mutable, and the mutation rate seemed to increase with the father's age. Hum Mutat 26(6), 520-528, 2005. (c) 2005 Wiley-Liss, Inc.

Age Factors↗
PubMed2005

Mitochondrial DNA haplotyping revealed the presence of mixed up benign and neoplastic tissue sections from two individuals on the same prostatic biopsy slide.

DNA typing was requested to investigate a presumptive cancer diagnosis error by confirming whether benign and cancerous prostatic tissue in the same presurgical haematoxylin and eosin stained slide belonged to the same person. After independent histological re-examination of the slide by a pathologist, manual slide dissection was used to guarantee independent and high recovery DNA isolation from each tissue section, avoiding carryover and background contamination. Nuclear DNA quantification performed by real time polymerase chain reaction (PCR) revealed the absence of human DNA for short tandem repeat (STR) typing. Mitochondrial DNA was only obtained by performing PCR of very short fragments ( approximately 100 bp), indicating high DNA degradation. Different low frequency hypervariable region I haplotypes were obtained from each tissue section (normal tissue section haplotype: 16224C, 16234T, 16311C, 16356C; cancer tissue section haplotype: 16256T, 16270T, 16293G). Only the normal tissue section haplotype matched that obtained from the patient's blood sample, indicating that the cancer tissue section originated from an unknown patient. These results supported the hypothesis of sample mix up during block processing or slide preparation by a carryover mechanism. Mitochondrial genetic typing is recommended to exclude the possibility of carryover artefacts when low DNA content and high degradation compromise conventional STR typing.

Artifacts↗
PubMed2004

Analysis of cerebro-spinal fluid protein composition in early developmental stages in chick embryos.

Foetal cerebro-spinal fluid (CSF) has a very high protein concentration when compared to adult CSF, and in many species five major protein fractions have been described. However, the protein concentration and composition in CSF during early developmental stages remains largely unknown. Our results show that in the earliest stages (18 to 30 H.H.) of chick development there is a progressive increase in CSF protein concentration until foetal values are attained. In addition, by performing electrophoretic separation and high-sensitivity silver staining, we were able to identify a total of 21 different protein fractions in the chick embryo CSF. In accordance with the developmental pattern of their concentration, these can be classified as follows: A: high-concentration fractions which corresponded with the ones described in foetal CSF by other authors; B: low-concentration fractions which remained stable throughout the period studied; C: low-concentration fractions which show changes during this period. The evolution and molecular weight of the latter group suggest the possibility of an important biological role. Our data demonstrate that all the CSF protein fractions are present in embryonic serum; this could mean that the specific transport mechanisms in neuroepithelial cells described in the foetal period evolve in very early stages of development. In conclusion, this paper offers an accurate study of the protein composition of chick embryonic CSF, which will help the understanding of the influences on neuroepithelial stem cells during development and, as a result, the appropriate conditions for the in vitro study of embryonic/foetal nervous tissue cells.

Animals↗
PubMed2004

Neural cell adhesion molecule expression in plasma cells in bone marrow biopsies and aspirates allows discrimination between multiple myeloma, monoclonal gammopathy of uncertain significance and polyclonal plasmacytosis.

AIMS: Differential diagnosis between multiple myeloma (MM), monoclonal gammopathy of uncertain significance (MGUS), and polyclonal plasmacytosis may be difficult in cases with not much bone marrow infiltration. Normal plasma cells express the antigens CD138, CD38, CD19, CD10 and D-related human leucocyte antigen (HLA-DR). Myelomatous plasma cells lack B lymphoid-associated markers and may express cell surface antigens associated with other haematopoietic lineages such as NCAM/CD56 (neural cell adhesion molecule). Recently, a monoclonal antibody, anti-CD56, has become available that can be used in fixed tissues embedded in paraffin, and it has been reported that osteoblastic cells of trabecular bone strongly express NCAM/CD56. METHODS AND RESULTS: We analysed NCAM molecule expression in 35 samples from patients with plasma cell disorders: 14 cases of MM, 16 cases of MGUS, and five cases of polyclonal plasmacytosis using immunohistochemistry in parallel in bone marrow core biopsies processed routinely and in bone marrow smears from the same patients. Of the MM samples 78% were CD56+ in smears and 92% positive in biopsies. We did not find strong CD56 expression in MGUS samples. One of five samples of polyclonal plasmacytosis was CD56+. A case was considered to be positive for CD56 expression if >50% of the CD138+ plasma cells expressed NCAM with an intensity on a par with that of the osteoblasts. CONCLUSION: We conclude that CD56 antibody is a very useful marker in the study of plasma cell proliferation in bone marrow biopsies and in bone marrow aspirates and is a great help in discriminating between MM, MGUS, and polyclonal plasmacytosis, especially in those cases with low infiltration.

Antibodies, Monoclonal↗
PubMed2003

The births of five Spanish babies from cryopreserved donated oocytes.

BACKGROUND: The technique of freezing oocytes is still not widely used. Reasons cited for this include the technique's low efficacy and the risk of aneuploidy. However, the introduction of technical changes (the type and concentration of cryoprotective substances; slow freezing and rapid thawing; and fertilization by ICSI) has led to improved results. We present four pregnancies obtained using mature oocytes (in metaphase II) that had been frozen and thawed. The oocytes were donated by young women who were not patients. METHODS: The frozen oocytes (n = 88) came from seven donors aged 18-25 years. The metaphase II oocytes, morphologically normal in appearance, were denuded of their cumulus-corona complex. The cryoprotective freezing solution contained 1,2-propanediol (1.5 mol/l) and sucrose (0.3 mol/l). Freezing was slow and thawing rapid. The oocytes were fertilized by ICSI. RESULTS: Seventy-nine of the 88 thawed oocytes survived (89.8%); 58 were fertilized (73.4% of all those microinjected); and 26 were transferred (44.8% of all those fertilized). Four pregnancies were produced after seven transfers (57.1%). Five children were born from four pregnancies. CONCLUSIONS: With the freezing/thawing technique used, oocyte survival was high ( approximately 90%). The pregnancy rate with frozen oocytes was similar to that obtained using fresh oocytes from donors ( approximately 50%).

Adult↗
PubMed2001

Expression of CCR9 beta-chemokine receptor is modulated in thymocyte differentiation and is selectively maintained in CD8(+) T cells from secondary lymphoid organs.

Chemokines appear to have an important role in the seeding of lymphoid progenitors in the thymus, the regulation of the coordinated movements of the maturing T cells within this organ, and the egress of the resulting naive T cells to secondary lymphoid organs. CCR9, the specific receptor for the beta-chemokine TECK/CCL25, is selectively expressed in thymus, lymph node, and spleen. Using a specific anti-CCR9 polyclonal antibody, K629, and a semiquantitative reverse transcriptase-polymerase chain reaction procedure, a detailed study of CCR9 expression in the thymus and secondary lymphoid organs was performed. The results show that CD4(+)CD8(+) double-positive thymocytes have the highest CCR9 expression in thymus. Single-positive CD8(+) thymocytes continue to express this receptor after abandoning the thymus as mature naive T cells, as suggested by the existence of a CD8(+)CD69(low)CD62L(high) CCR9(+) cell subset. Consistent with this, CD8(+) lymphocytes from lymph nodes, spleen, and Peyer patches express a functional CCR9, as its expression correlates with migration in response to CCL25. Conversely, CD4(+) thymocytes lose CCR9 before abandoning the thymus, and CD4(+) T cells from secondary lymphoid organs also lack CCR9 expression. Analysis of CCR9 expression in thymocytes from mice of different ages showed that CCR9 levels are affected by age, as this receptor is more abundant, and its response to CCL25 is more potent in newborn animals. Collectively, these results suggest that CCR9 has a role in thymocyte development throughout murine life, with clear differences between the CD4(+) and CD8(+) lineages.

Aging↗
PubMed2001

Origin and differentiation of dendritic cells.

Despite extensive, recent research on the development of dendritic cells (DCs), their origin is a controversial issue in immunology, with important implications regarding their use in cancer immunotherapy. Although, under defined experimental conditions, DCs can be generated from myeloid or lymphoid precursors, the differentiation pathways that generate DCs in vivo remain unknown largely. Indeed, experimental results suggest that the in vivo differentiation of a particular DC subpopulation could be unrelated to its possible experimental generation. Nevertheless, the analysis of DC differentiation by in vivo and in vitro experimental systems could provide important insights into the control of the physiological development of DCs and constitutes the basis of a model of common DC differentiation that we propose.

Animals↗
PubMed2001

Neuropathological findings in a patient with epilepsy and the Parry-Romberg syndrome.

PURPOSE: The Parry-Romberg syndrome is an unusual disorder frequently associated with epilepsy. The origin of this disease, and the cause of epilepsy, are unknown. This study is the first reported case of the Parry-Romberg syndrome, with intractable temporal lobe epilepsy, in which detailed microanatomic analyses have been performed on resected brain tissue obtained after surgical intervention. METHODS: Standard histopathologic methods and correlative light and electron microscopy, combined with immunocytochemical techniques, were used to study in detail the synaptic microorganization of the resected hippocampal formation. RESULTS: After surgery, the patient was seizure free (follow-up period of 4 years and 7 months). The resected temporal lobe showed a variety of dramatic microanatomic alterations (small groups of ectopic cells, neuronal loss, gliosis, and activated microglial cells) in mesial structures, including the entorhinal cortex, subiculum, and dentate gyrus. At the electron-microscopic level, we found that in the dentate gyrus, the number of synapses in the cell-sparse region adjacent to the ectopic mass of neurons was almost twice that found in the molecular and polymorph cell layers, indicating the intrusion of neuritic processes and synapse formation. In addition, the symmetrical axosomatic synapses characteristically found on granule cells, which are likely derived from gamma-aminobutyric acid (GABA)ergic inhibitory basket cells, were not observed. CONCLUSION: The complete seizure relief after surgery suggests that the pacemaker region(s) of seizure activity were within the resected tissue. However, we do not know which of the multiple neuropathologic findings reported here were the primary cause of seizure activity. Nevertheless, the changes found in the dentate gyrus circuitry appear to be among the most important alterations that would lead to epilepsy.

Adult↗
PubMed2001

DNA typing from skeletal remains: evaluation of multiplex and megaplex STR systems on DNA isolated from bone and teeth samples.

AIM: To evaluate the performance of three multiplex short tandem repeat (STR) systems (AmpflSTR Profiler, AmpflSTR Profiler Plus, and AmpflSTR COfiler), and a megaplex STR system (PowerPlex 16) on DNA extracted from the skeletal remains. By performing a microbial DNA challenge study, we also evaluated the influence of microbial DNA on human DNA typing. METHODS: A subset of 86 DNA extracts isolated from 8-50 years old bone and teeth samples, corresponding to 20 identification cases from mass graves in Croatia and Bosnia and Herzegovina, and to 4 paternity cases involving deceased parents in Spain, were analyzed by the above systems. RESULTS: Bone samples with no detectable human DNA (tested with Quantiblot), as well as teeth samples with detectable human DNA, were successfully amplified. Surprisingly, even in highly degraded samples, PowerPlex 16 offered very robust amplification for the both Penta E and Penta D markers. We observed a few non-specific extra peaks of 202 and 308 base pairs, which appeared to match 16S rRNA of the Pseudomonas halodenitrificans. CONCLUSION: AmpflSTR Profiler Kit, AmpflSTR Profiler Plus Kit, the AmpflSTR COfiler Kit, and the PowerPlex 16 system are very sensitive multiplex STR amplification systems, which can be successfully used to obtain a multilocus STR profile from old teeth and bone samples with minimal amounts (pg) of human DNA or even with no detectable human DNA.

Bone and Bones↗
PubMed2000

Concept of lymphoid versus myeloid dendritic cell lineages revisited: both CD8alpha(-) and CD8alpha(+) dendritic cells are generated from CD4(low) lymphoid-committed precursors.

Two dendritic cell (DC) subsets have been identified in the murine system on the basis of their differential CD8alpha expression. CD8alpha(+) DCs and CD8alpha(-) DCs are considered as lymphoid- and myeloid-derived, respectively, because CD8alpha(+) but not CD8alpha(-) splenic DCs were generated from lymphoid CD4(low) precursors, devoid of myeloid reconstitution potential. Although CD8alpha(-) DCs were first described as negative for CD4, our results demonstrate that approximately 70% of them are CD4(+). Besides CD4(-) CD8alpha(-) and CD4(+) CD8alpha(-) DCs displayed a similar phenotype and T-cell stimulatory potential in mixed lymphocyte reaction (MLR), although among CD8alpha(-) DCs, the CD4(+) subset appears to have a higher endocytic capacity. Finally, experiments of DC reconstitution after irradiation in which, in contrast to previous studies, donor-type DCs were analyzed without depleting CD4(+) cells, revealed that both CD8alpha(+) DCs and CD8alpha(-) DCs were generated after transfer of CD4(low) precursors. These data suggest that both CD8alpha(+) and CD8alpha(-) DCs derive from a common precursor and, hence, do not support the concept of the CD8alpha(+) lymphoid-derived and CD8alpha(-) myeloid-derived DC lineages. However, because this hypothesis has to be confirmed at the clonal level, it remains possible that CD8alpha(-) DCs arise from a myeloid precursor within the CD4(low) precursor population or, alternatively, that both CD8alpha(+) and CD8alpha(-) DCs derive from an independent nonlymphoid, nonmyeloid DC precursor. In conclusion, although we favor the hypothesis that both CD8alpha(+) and CD8alpha(-) DCs derive from a lymphoid-committed precursor, a precise study of the differentiation process of CD8alpha(+) and CD8alpha(-) DCs is required to define conclusively their origin.

Animals↗
PubMed2000

Langerhans cells develop from a lymphoid-committed precursor.

Langerhans cells (LCs) are specialized dendritic cells (DCs) strategically located in stratified epithelia, such as those of the skin, oral cavity, pharynx, esophagus, upper airways, urethra, and female reproductive tract, which are exposed to a wide variety of microbial pathogens. LCs play an essential role in the induction of T-lymphocyte responses against viruses, bacteria, and parasites that gain access to those epithelial surfaces, due to their high antigen capture and processing potential and their capacity to present antigen peptides to T cells on migration to the lymph nodes.(1) Although LCs have been classically considered of myeloid origin, recent reports, which demonstrate the existence of lymphoid DCs derived from multipotent lymphoid precursors devoid of myeloid differentiation potential,(2-5) raise the question of the lymphoid or myeloid origin of LCs. The present study shows that mouse lymphoid-committed CD4(low) precursors, with the capacity to generate T cells, B cells, CD8(+) lymphoid DCs, and natural killer cells,(26) also generate epidermal LCs on intravenous transfer, supporting the view that LCs belong to the lymphoid lineage. (Blood. 2000;96:1633-1637)

Animals↗
PubMed2000

Langerhans cells acquire a CD8+ dendritic cell phenotype on maturation by CD40 ligation.

Dendritic cell (DC) reconstitution experiments and phenotypic analysis of DC subpopulations have allowed the definition in the mouse of two main DC categories: CD8+ lymphoid DCs and CD8- myeloid DCs. With regard to Langerhans cells (LCs), which represent immature DCs differentiating into mature DCs on migration to the lymph nodes after an antigenic stimulation, although classically considered as myeloid DCs, there is no experimental evidence of their origin. It has been recently shown that mouse LCs, negative for CD8 and LFA-1, undergo CD8/LFA-1 up-regulation on migration, suggesting that LCs belong to the CD8+ lymphoid DC lineage. To further reinforce this hypothesis, we have analyzed the modulation of CD8 expression by LCs on culture with molecules known to induce LC maturation. Our results show that LC acquired a CD8+ lymphoid phenotype on CD40 ligation.

Animals↗
PubMed2000

Basal lamina heparan sulphate proteoglycan is involved in otic placode invagination in chick embryos.

Formation of the otocyst from the otic placode appears to differ from invagination of other cup-shaped organ primordia. It is known that the cellular cytoskeleton plays a limited role in otic placode invagination, whilst the extracellular matrix underlying the otic primordium intervenes in the folding process. In this study we have analysed the role of the basal lamina heparan sulphate proteoglycan in otic primordium invagination. At 10 H.H. stage, heparan sulphate proteoglycan immunomarking begins to appear on the otic placode basal lamina, increasing noticeably at 13 H.H. stage, coinciding with maximum folding of the otic epithelium, and is still present at later stages. Enzyme degradation of heparan sulphate proteoglycan in the otic primordium basal lamina, by means of microinjection with heparinase III prior to folding, significantly disrupts invagination of the otic placode, which remains practically flat, with a significant reduction in the depth of the otic pit and an increase in the diameter of the otic opening. The immunocytochemistry analysis revealed a notable depletion of basal lamina heparan sulphate proteoglycan in the otic primordia microinjected with heparinase, with no statistically significant differences observed in the volume or rate of cell proliferation in the otic epithelium relative to the control, which suggests that heparan sulphate proteoglycan disruption does not interfere with the epithelial growth. In addition, a study of apoptosis distribution by the TUNEL method confirmed that treatment with heparinase does not cause interference with cell survival in the otic epithelium. Our findings support the theory that otic primordium invagination may be regulated, at least in part, by the basal lamina components, which might contribute towards anchoring the otic epithelium to adjacent structures.

Animals↗