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I Esteban

Publications and source records attributed to I Esteban.

36 records · Page 2Linked to original sources
PubMed1997

TrkA neutrophin receptor protein in the rat and human thymus.

BACKGROUND: Increasing evidence suggests that nerve growth factor (NGF), and probably other neurotrophins, are involved in the control of lymphoid organs and immunocompetent cells that express neurotrophins and/or their receptors. In the rat thymus, mRNA for TrkA (an essential component of the NGF signal transducing receptor) has been found primarily in stromal cells. The present study was undertaken to analyze the occurrence and localization of TrkA in the rat and human thymus, using Western blot and immunohistochemical techniques. METHODS: Thymuses from human fetuses (estimated gestational ages of 29 and 32 weeks) and newborns (3 and 4 weeks old), as well as from 3-month-old rats were used. Human and rat samples were fixed in buffered 10% formaldehyde, paraffin-embedded, and processed for immunohistochemistry. Moreover, rat thymus samples were processed for Western blot analysis. RESULTS: A protein band consistent with full-length TrkA (approximately 140 kDa) was detected in the rat thymus. Immunoreactivity (IR) for TrkA was exclusively found in thymic epithelial cells of both rat and human, identified because they also displayed cytokeratin IR. Interestingly, species-specific differences were noted for the expression of TrkA in different subtypes of thymic epithelial cells. Apparently, no immunolabelling was observed in other stromal cells or in lymphocytes. CONCLUSIONS: These results suggest that TrkA ligands may be involved in the control of thymic epithelial cells. This could be of potential importance because of the involvement of these cells in providing an appropriate microenvironment for maturation and selection of T lymphocytes.

Animals↗
PubMed1996

Distribution of immunoreactivity for cytoskeletal (microtubule, microtubule-associated, and neurofilament) proteins in adult human dorsal root ganglia.

BACKGROUND: The cytoskeleton of mature neurons consists of three main types of filamentous structures: microtubules (or neurotubules) neurofilaments and microfilaments, and of the so-called associated proteins. Neurotubules are formed by alpha- and beta-tubulin; neurofilaments are comprised of three protein subunits (68, 160, and 200 kDa of molecular weight), referred to here as neurofilament proteins (NFPs). The microtubule-associated proteins (MAPs) and tau-proteins form cross bridges between microtubules and other cytoskeletal constituents, as well as cellular organelles. This study analyzes the distribution of several cytoskeletal proteins in adult human dorsal root ganglia (DRG). METHODS: Sections of formaldehyde-fixed, paraffin-embedded adult human DRG were processed for PAP immunohistochemistry. Mouse monoclonal antibodies against specific epitopes of alpha- and beta-tubulin, MAP-1, MAP-2, MAP-5, tau-protein, and NFPs (68, 160, and 200 kDa) were used. Furthermore, a quantitative image analysis (optic microdensitometry) was performed to establish the relationship between neuronal size and intensity of immunostaining. RESULTS: Most of DRG neuron cell bodies displayed immunoreactivity for all assessed antibodies, with the exception of MAP2, which was absent. Nevertheless, the neuronal perikarya showed an heterogeneous pattern of immunoreactivity, which was not related to neuronal profile size. Positive immunolabelling was also observed in satellite cells and Schwann cells for microtubule and MAP1 proteins, and for tau-protein in Schwann cells. CONCLUSIONS: Adult human primary sensory neurons in DRG express immunoreactivity for neurotubule and neurofilament proteins, as well as for some microtubule-associated proteins. However, since large heterogeneity was observed in the expression of those proteins, we conclude that the expression of cytoskeletal proteins is not a criterion to establish DRG neuronal subtypes.

Adult↗
PubMed1996

Distribution of p75 and trk-neurotrophin receptor proteins in adult human sympathetic ganglia.

We investigated the expression of immunoreactivity (IR) for low- (p75) and high-affinity (trk proteins) neurotrophin-receptor proteins in adult human paravertebral-sympathetic ganglion neurons. Mouse monoclonal antibodies against the pan-neurotrophin-receptor p75, and rabbit polyclonal antibodies against specific epitopes of the intracytoplasmic domain on trk neurotrophin-receptor proteins were used in fresh unfixed and formaldehyde-fixed paraffin-embedded sympathetic ganglia. All adult human paravertebral-sympathetic neurons displayed trkA neurotrophin-receptor-like protein IR, 10% express trkC neurotrophin-receptor-like protein IR, 37-44% show p75 IR, and no IR was obtained for trkB neurotrophin-receptor-like protein. The intensity of immunostaining was independent of the neuron size. Labelling of non-neuronal tissues, especially blood-vessel walls, was observed for p75, trkA and trkC neurotrophin-receptor proteins. These results indicate that overlapping exists in the expression of p75 and trk neurotrophin-receptor proteins in adult human paravertebral-sympathetic neurons, and suggest that neurotrophins might act on these neurons.

Adult↗
PubMed1995

Neurotrophin receptor proteins immunoreactivity in the rat cerebellar cortex as a function of age.

The influence of age on immunohistochemically demonstrable neurotrophin receptor proteins (p75, trkA-, trkB-, and trkC-proteins) was studied in the cerebellar cortex of Wistar male rats aged 3 (young), 12 (adult) and 24 (old) months. The number of Purkinje neurons displaying p75, trkA- and trkC-like proteins immunoreactivity (IR), as well as the intensity of p75 and trkA-like protein IR, were significantly reduced in aged rats in comparison with 3 and 12-month-old rats. The intensity of trkC-like protein in the cytoplasm of Purkinje neurons remained unchanged for all the period studied. Moreover, no significant age-dependent changes were observed in the density of p75 or trkC-like proteins IR in the granule neurons layer. The molecular layer showed faint p75 IR which decreased as a function of age. No immunolabelling for neuronal trkB-like proteins was observed, but trkB- and trkC-like proteins IR was found in non-neuronal cells. These results suggest that cerebellar cortex neurons are responsive to and/or dependent upon different neurotrophins. Moreover, the age-dependent impairment in the expression of some neurotrophin receptors in Purkinje neurons, but not in the granule neurons, lends support to a role for neurotrophins in cerebellar aging.

Age Factors↗
PubMed1995

Immunohistochemical localization of laminin and type IV collagen in human cutaneous sensory nerve formations.

We used immunohistochemical techniques and monoclonal antibodies to localize two basement membrane components (laminin and type IV collagen) in the nerves and sensory nerve formations, or corpuscles, supplying human digital skin. Furthermore, neurofilament proteins, S-100 protein and epithelial membrane antigen were studied in parallel. In dermal nerve trunks, immunostaining for laminin and type IV collagen was found to be co-localized in the perineurium and the Schwann cells, the stronger immunoreactivity being at the external surface of the cells. In the Meissner digital corpuscles, the immunoreactivity for laminin and type IV collagen was mainly observed underlying the cell surface of lamellar cells, while the cytoplasm was weakly immunolabelled or unlabelled. Finally, within Pacinian corpuscles co-localization of the two basement membrane molecules was encountered in the inner core, intermediate layer, outer core and capsule. Laminin and type IV collagen immunoreactivities were also found in blood vessels and sweat glands, apparently labelling basement membrane structures. The present results provide evidence for the presence of basement membrane in all periaxonic cells forming human cutaneous sensory nerve formations, and suggest that all of them are able to synthesize and release some basement membrane components, such as laminin and type IV collagen. The possible role of laminin in sensory nerve formations is discussed.

Adolescent↗
PubMed1995

Immunoreactivity for beta/A4 protein, but not for its precursor, in human chromaffin cells.

The present study was designed to establish a) whether chromaffin cells of the human adrenal medulla express immunoreactivity for beta-amyloid precursor protein (beta APP) and/or beta-amyloid protein (beta/A4); and b) whether cells expressing one or both of the above-mentioned proteins display immunoreactivity for the low- (gp75) and/or the high-affinity (gp140-trkA) nerve growth factor receptor. To identify chromaffin cells and their supporting cells, chromogranin A, neurofilament proteins, and S-100 protein were studied in parallel. Beta APP and beta/A4 immunoreactivity (IR) was observed primarily labeling two different cell populations, without colocalization: Beta APP IR was found in the adrenal cortical cells, which were mainly localized in the reticulate layer and in the blood vessel walls, whereas beta/A4 IR was observed in the chromaffin cells. Furthermore, supporting cells were also immunoreactive for beta/A4, and sympathetic ganglionic cells were immunoreactive for both beta APP and beta/A4. Interestingly, clusters of cells expressing beta/A4 IR also displayed gp 75 IR and/or gp140-trkA IR. Finally, all chromaffin cells (identified by chromogranin A IR) were immunolabeled for the 200 kDa neurofilament subunit, but not for a phosphorylated epitope of this protein. These results demonstrate the occurrence of beta/A4 IR, but not of beta APP, in the chromaffin cells of the human adrenal gland. The complementary distribution of amyloid-related proteins, and the possible involvement of neurotrophins in beta/A4 metabolism are discussed.

Aged↗
PubMed1995

Neurotrophin receptor proteins immunoreactivity in human gastrointestinal endocrine cells.

The distribution of neurotrophin receptors (p75, trkA-, trkB-, and trkC-receptor proteins) was studied by immunohistochemistry on sections of human gastrointestinal tract mucosa from esophagus through rectum. Moreover, chromogranin A (CgA) was studied in parallel to identify endocrine cells (EC). In all of the analyzed samples there was specific immunoreactivity (IR) for trkB-receptor protein in EC, the percentage of which varied between 26 +/- 0.6% for the duodenum and 78 +/- 3% for the sigmoid colon. EC displaying trkC-receptor protein IR were also encountered, in some cases, in EC of the gastric fundus (9%), duodenum (12%), jejune (23%), and colon (12%); trkA-receptor protein IR was occasionally present labelling EC in the jejune (52%), ileum (25%), and sigmoid colon (18%); finally, p75 was in 21% of EC exclusively in one case in the ileum. In addition to EC, IR for all assessed antigens was also present in the submucous blood vessels. Our results provide evidence for the occurrence of neurotrophin receptor proteins in nonneuronal tissues and suggest that neurotrophins, especially that binding trkB receptor proteins, can regulate a subpopulation of EC cells. However, whether EC expressing different trk receptor proteins represent neurochemical subtypes of EC, and whether the identified trk receptor proteins correspond to functional receptors, remain to be elucidated.

Adult↗
PubMed1994

Immunoreactivity for phosphorylated 200-kDa neurofilament subunit is heterogeneously expressed in human sympathetic and primary sensory neurons.

This study was undertaken to investigate whether human sensory and sympathetic neurons contain phosphorylated neurofilament proteins, and whether they may be classified on the basis of this property, as in other mammalian species. The distribution of the phosphorylated 200-kDa neurofilament protein subunit (p200-NFP) was investigated in lumbar sympathetic and dorsal root ganglia by means of the RT97 monoclonal antibody (against p200-NFP). The intensity of immunostaining, and the size of neuronal body profiles were measured in order to define different neuron subclasses. In dorsal root ganglia, most of the neuronal profiles (96%) were p200-NFP immunoreactive, and the intensity of immunostaining was not related to neuronal perikarya size. In the lumbar paravertebral sympathetic ganglia, virtually all neurons displayed p200-NFP immunoreactivity, and the intensity of immunolabelling was also independent of the size of the neuronal somata. These results demonstrate heterogeneity in the expression of p200-NFP immunoreactivity in human sympathetic and sensory neurons. In contrast to other mammalian species, RT97 immunolabelling cannot be used as a discriminative marker for the two main types of human primary sensory neurons. On the other hand, our findings provide evidence for the occurrence of phosphorylated neurofilaments within peripheral neuron cell bodies.

Adult↗
PubMed1994

[Infection with hepatitis B and C viruses in the mentally retarded].

AIM: To study the prevalence of hepatitis C virus infection (HCV) and the associated risk factors in an institution for the mentally retarded, in addition to its relation with hepatitis B infection (HBV). METHODS: The presence of antibodies against the HCV (anti-HCV) and markers for the HBV was evaluated in 94 mentally retarded subjects admitted to a single institution. Information concerning the sex, age, length of admission, type and degree of mental retardation, history of sexual promiscuity, surgery and blood transfusions was collected in every individual. RESULTS: The prevalence of infection by HBV was 22.3%. Only one individual was detected as being positive for the HCV.

Adolescent↗
PubMed1983

[Ebstein's anomaly of the tricuspid valve. Study of 13 cases in childhood].

We describe 13 cases of Ebstein's anomaly of the tricuspid valve. Seventy percent of there cases were detected at one month of age. Ten patients died and 9 presented associated cardiac anomalies. Signs of right heart failure were the clinical date that made possible the diagnosis of the disease in the most severe cases in the neonatal period. Only two patients had alteration of the cardiac rhythm: One had tachycardia that ended with ventricular fibrillation and the other had a 2:1 heart block. Echocardiography was very useful to establish the diagnosis: one hundred percent of the patients showed a delay in closing of the tricuspid in relation to the mitral valve, with a range of 0,03 to 0,06 seconds. Angiocardiographic studies revealed a tricuspid valve displacement in 8 cases, and double contour image in 6. The septal and posterior leaflets were hypoplasic in the 10 anatomic cases and in 80 percent of them it was possible to differentiate the cords from the papillary muscles.

Child, Preschool↗
PubMed1978

Aortic atresia with normal left ventricle and intact ventricular septum.

We report a case of aortic atresia with biventricular hypertrophy and death due to cardiac insufficiency (at 5 1/2 days of age). In the necropsy a normally sized left ventricle was observed, with endocardiac fibroelastosis, anomalous mitral arcade, intact interventricular septum and atresia of the aortic valve. The ascending aorta was moderately hypoplasic; there was a foramen ovale and persistent ductus arteriosus. We believe that this is the first case that has been reported of this anomaly occurring with a normal left ventricle and intact ventricular septum.

Aorta↗
PubMed1977

[Corrected transposition of the great arteries. Study of 14 cases (author's transl)].

We have studied 14 patients of corrected transposition, 12 with situs solitus and 2 with situs inversus. In all the patients, excepting one, a clinical, radiological and angiocardiographical study was performed. The associated anomalies were determining elements of the clinical situation; the patients with pulmonary obstruction and interventricular communication had cianosis, while the 4 patients with aortic obstruction or anomalies type left Ebstein show cardiac insufficiency. The simple radiological study helped us to determinate the ascendent aorta in the left side of the heart, in 9 cases. It was unusual to see the droped hilium in the right hemitorax. The more significants electrical signs were: The presence of complete A-V block, Q-waves in D2, D3 and aVF, absence of right waves in precordial leads in most of the patients and a negative T wave in a VL. Summarizing, authors believe that in this type of defects selective injection of contrast in both ventricles is the best method to establish the difference between corrected transposition and other cardiopathies with the aorta situated at the left side of the pulmonary artery.

Adult↗
PubMed1975

[Left atrio-ventricular parachute valve. Clinical, angiocardiographic and anatomic study, presentation of 6 cases].

Report of 6 cases of parachute left atrio-ventricular valve, combined with complex malformations in 4. Age ranged from 24 hours to 9 years, five of them being less than 3 months old. Four girsl and two boys. All were examined post-mortem and two had angiography and chateterization. This series was compared with those described in the world literature.

Abnormalities, Multiple↗
PubMedDate not supplied

Systemic sclerosis developing in association with the use of interferon alpha therapy for chronic viral hepatitis.

In 1992 interferon alpha (IFNalpha) was approved by the FDA for the treatment of chronic viral hepatitis B and C. Since then IFNalpha has been implicated in the development of several autoantibodies as well as in the development or exacerbation of various autoimmune disorders. Herein, we describe a 47-year-old female who developed a limited form of systemic sclerosis (SSc) with lung involvement 6 months after the institution of IFNalpha therapy for chronic active hepatitis C. There was no family or personal history of autoimmune diseases. We speculate that the immunomodulatory effects of IFNalpha triggered the clinical manifestations of SSc in this patient. To our knowledge, this is the second case of SSc developing after therapy with IFNalpha and the first in a patient treated for chronic viral hepatitis C.

Antiviral Agents↗
PubMedDate not supplied

[Anomalous pulmonary venous drainage to inferior vena cava (author's transl)].

Four cases between one day of life and seven years are presented. Two of them were males and two females. All of them had cardiac pulsation palpable to the right of the sternum, one with some bulging of the left hemitorax. In two cases a systolic murmur was heard over the second intercostal space associated with fixed splitting of the second sound and the other case presented recurrent infections processes of the lung dying ultimately from bronchoneumonia. On the simple X-ray displacement of the mediastine towards the right side, dextroposition of the heart, right pulmonary hyoplasia, enlargement of the right atrium and image in "scimitar" (obvious in two cases and possibly existed in the other two) was observed. In three cases a lung scan was carried out which showed a marked decrease in perfusion of the right lung. Angiocardiography in all cases as able to demonstrate anomalous venous drainage of the right lung to inferior vena cava directly.

Abnormalities, Multiple↗