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Biomedical subjects

M A Marín

Publications and source records attributed to M A Marín.

10 recordsLinked to original sources
PubMed2006

Choline acetyl transferase and neuropeptide immunoreactivities are colocalized in somata, but preferentially localized in distinct axon fibers and boutons of cat sympathetic preganglionic neurons.

Cholinergic sympathetic preganglionic neurons (SPN) coexpress the biosynthetic enzyme for acetylcholine, choline acetyl-transferase (ChAT), and neuropeptides such as enkephalin (ENK) in their cell bodies. However, it is not clear whether they also coexpress ChAT and neuropeptides in axon fibers and boutons. To explore coexpression of ChAT and neuropeptides in somata and axon processes of SPN, we investigated, using immunohistochemistry, retrograde labeling, confocal analysis, and tridimensional reconstruction, whether ChAT and the peptides neurotensin, methionine-ENK, somatostatin, calcitonin gene-related peptide, and vasoactive intestinal peptide colocalize in somata, axons fibers, and boutons of cat SPN. Practically, complete colocalization for these peptides and ChAT was observed in SPN somata. Conversely, in most instances we observed independent localization of immunoreactivity (IR) for ChAT and the peptides in axon fibers and boutons. The minor colocalization between ChAT- and peptide-IR in preganglionic fibers could correspond to a sequential axonal transport of ChAT and peptides, since we observed coexistence of these transmitters after blocking axonal transport. Contrary to Dale's principle, our results suggest that SPN can synthesize ChAT and peptides in their cell bodies and route them to distinct axon boutons or terminals in sympathetic ganglia. Presence of axon boutons containing either ChAT or neuropeptides lead us to suggest a new neurochemical pattern of cotransmission in sympathetic ganglia based on the concurrent release of transmitters and cotransmitters from distinct presynaptic boutons, rather than in the corelease of these mediators from the same axon process. The possibility that cellular segregation could be transient and depend on functional requirements is considered.

Animals↗
PubMed2005

[Neuropsychiatric disorders associated with streptococci: a case report].

Compulsive neuropsychiatric disorders are common in children and the most frequent is Gilles de la Tourette syndrome. Recently, a new disease has been described: the PANDAS syndrome (pediatric autoimmune neuropsychiatric disorders associated with streptococci). The etiology of this syndrome is uncertain but it has been associated with recent group A streptococcal infection (GAS). After an episode of pharyngitis, a boy aged 3 years and 9 months showed abrupt onset of a variety of neurobehavioral problems such as tics (consisting of elevation of the head and ipsilateral shoulder, winking, and grimaces) and compulsions (such as repeatedly hitting objects). A complete biochemical study was performed, including Cu and ceruloplasmin (which had normal values), antistreptolysin O (ASLO) and anti-DNAse (showing elevated values). Pharyngeal culture revealed GAS. The child was initially treated with valproic acid, but his subsequent improvement coincided with penicillin treatment for 10 days. Three months afterwards, ASLO values were reduced and at the 6-month follow-up the improvement was maintained even after suspension of valproic acid. Immunohistochemical studies were requested. PANDAS syndrome was first described in 1998 in a group of children who presented 1) obsessive compulsive disorders and/or tics, 2) episodic course with abrupt exacerbations, 3) abnormal results of neurologic examination (choreiform movements), and 4) temporal relation between GAS infection and onset of symptoms. The etiology of this syndrome is unclear, and it has been postulated that certain streptococcal antigens trigger antibodies which, through a process of molecular mimicry, cross-react with epitopes on the basal ganglia of susceptible hosts, such as the B8/17 antigen, among others. Current recommendations include penicillin treatment of each exacerbation with positive throat culture, and more aggressive therapies (intravenous immunoglobulin or plasmapheresis) when symptoms are severe. We believe that the case presented herein is a probable PANDAS syndrome, which would be the first case described in Spain.

Autoimmune Diseases↗
PubMed1999

Clinical application of amniotic membranes on a patient with epidermolysis bullosa.

The case of a patient with dystrophic epidermolysis bullosa treated with radiosterilised amniotic membranes is presented. The disorder is a congenital disease characterised by a poor desmosomal junction in the keratinocyte membrane. After proper donor screening, amnios were collected at Hospital Central Sur de Alta Especialidad (HCSAE), PEMEX and microbiological analysis was performed at Universidad Nacional Autónoma de México, FQUNAM, (Biology Dept. of the Chemistry Faculty, National Autonomous University of Mexico), before and after radiation sterilisation. Processing, packaging and sterilisation were performed at Instituto Nacional de Investigaciones Nucleares, ININ, (National Nuclear Research Institute). The patient, a ten-year-old boy with severe malnutrition, extensive loss of skin and pseudomonad infection in the whole body, was treated with gentle debridement in a Hubbard bath. Later amnion application was performed with sterilised amnios by using two different processes, in one of which the amnion was sterilised with paracetic acid, preserved in glycerol, kindly donated by the German Institute for Tissue and Cell Replacement and applied by Dr. Johannes C. Bruck, IAEA visiting expert, and the other amnion was processed at ININ: air dried and sterilised by gamma radiation at dose of 30 kGy. After spontaneous epithelisation was successfully promoted for seven days, the pain was alleviated and mobility was improved in a few hours and the patient's general condition was so improved that in a month he was discharged. Unfortunately, because this disease is revertive and has malignant degeneration, the prognosis is not good.

Amnion↗
PubMed1997

Differential perceptions of drinkers of alcoholic beverages by Mexican-Americans and non-Hispanic whites.

Random samples of 534 Mexican-Americans and 616 non-Hispanic Whites were interviewed over the telephone in San José, California and in San Antonio, Texas. Mexican-Americans tended to favor most frequently negative traits for their perceptions of drinkers than non-Hispanic Whites. Excessive drinkers were perceived most frequently in generally negative fashion by members of both ethnic groups although they were also perceived as happy persons. Highly acculturated Mexican-Americans reported perceptions of drinkers and of excessive drinkers that differed from those held by the less acculturated Mexican-Americans and that resembled those held by the non-Hispanic White respondents.

Adult↗
PubMed1992

Requirements for the production of high-titre C3 nephritic factor (NEF) antibody in vitro.

C3 nephritic factor (NEF) is an IgG autoantibody directed against neoantigenic determinants of the alternative C3 convertase (C3b.Bb). Structural and functional studies require important amounts of this antibody, which are difficult to obtain from patients' sera. We have developed a method for increasing NEF production in vitro. Epstein-Barr virus is a herpes virus which transforms B lymphocytes. Some authors were able to induce the production of NEF in vitro after infection with Epstein-Barr virus (EBV). These works were preformed without any previous cellular selection of B cells. We have performed a method of preselecting antigen-binding cells prior to EBV transformation. Non-preselected cells yielded 0.16 U/million cells in culture (U/M) of NEF antibody, whereas enriched cells for NEF antibody in eliminated 8 U/M (sheep erythrocytes coated with anti-IgG, A, M). Specific NEF synthesis can be increased, in peripheral blood mononuclear cells (PBMC) from patients by in vitro stimulation with the antigens recognized by NEF [C3b.Bb, 21,000 MW protein from patients' E membranes and 26,000 MW protein from sheep E membranes (ShE)]. The highest stimulation is induced by the C3b.Bb and by 26,000 MW protein, 21,000 MW protein had lowest stimulatory effect. In this work also we have shown that patients having NEF antibody in sera have an increase of the CD5-CD19 subset, when compared with the controls.

Antigens, CD↗
PubMed1991

Familial incidence of C3 nephritic factor.

C3 nephritic factor (NEF) has been found in 3 siblings presenting different (or none) degrees of renal disease. Other relatives, including their dead father, suffered from a renal illness. In 2 of the siblings, NEF activity was restricted to IgG1 and IgG3 subclasses. Familial NEF incidence and a shared C3 allotype and a common HLA haplotype including BfS alleles for the 3 NEF-positive siblings suggest that at least in our cases genetical factors may be involved in NEF generation.

Adolescent↗
PubMed1990

Determination of C3 nephritic factor activity by a microassay based on the peroxidase-like activity of the heme group.

We report a modification of a method for measuring the C3 nephritic factor, using the peroxidase activity of the heme group. This modification increases the sensitivity of the method, approximately seven-fold when NEF activities are measured in U/mL. It is less time-consuming and it allows the simultaneous testing of a larger number of samples, simplifying the screening of sera and ensuring an easy and simple test for the detection of NEF in purification processes as well as in in vitro production. The method could also be useful in other hemolytic assays.

Biological Assay↗
PubMed1988

Interaction between C3 nephritic factor and erythrocyte membranes. Presence of nephritic factor in patients' erythrocytes.

The presence of IgG has been observed by fluorescence microscopy in the erythrocytes of 5 patients with NEF antibody. IgG subclass distribution of the IgG bound was analyzed by fluorescence-activated cell sorter. NEF activity was also determined in the eluted antibodies from the erythrocyte membrane. Three of five patients had NEF antibody bound to the erythrocyte membrane. IgG subclass distribution of NEF antibody sera was also investigated by means of protein A-Sepharose and using monoclonal antibodies against human IgG subclasses. NEF activity was mediated by IgG3 alone in 3 patients and by a combination of IgG1 and IgG3 in 2 patients.

Antibodies↗
PubMed1987

C3 nephritic factor determination. A comparison between two methods.

C3 nephritic factor (NEF), an IgG autoantibody to the alternative pathway C3 convertase, is usually measured by crossed immunoelectrophoresis (CI) but recently a reliable haemolytic assay (HA) was described by Rother (1982). This method is more specific than CI because it is negative in sera with immune complexes, SLE and sera incubated with IgG aggregates. The haemolytic assay is sensitive enough to detect NEF antibody in serum from patients with only slightly low C3 levels and NEF negatives by CI. The haemolytic assay is easy to perform and reproducible, the interassay coefficient of variation being 10.7% compared to 64% in the CI. The intra-assay coefficient of variation in CI was 28% compared to 5.5% in the haemolytic assay. The haemolytic method enabled us to study the kinetic effects of NEF on C3b.Bb bound to sheep erythrocytes, and the lysis mediated by ShE.C3b.Bb.NEF complex. Also the C and NEF binding to sheep erythrocytes was studied.

Animals↗