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Biomedical subjects

F Marin

Publications and source records attributed to F Marin.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Surgical treatment of retrofoveal choroid neovascularization in multifocal choroiditis].

BACKGROUND: Surgical removal of subfoveal choroidal neovascularization allows visual improvement, especially in young patients. METHODS: Three eyes of 3 patients were prospectively studied. Subfoveal choroidal neovascularization was related to presumed ocular histoplasmosis syndrome. The surgical procedure included vitrectomy, surgical excision of the neovascular membrane, and air tamponnade. RESULTS: Follow-up was 6, 12 and 20 months. Vision improved in 2 eyes. In one case, recurrent extrafoveal neovascularization was treated with laser photocoagulation. DISCUSSION: Surgery seems to be an alternative to photocoagulation in subfoveal choroidal neovascularization in presumed ocular histoplasmosis.

Adult↗
PubMed1997

Analytical performance and clinical usefulness of two binding assays for growth hormone binding protein (GHBP) measurement: high performance liquid chromatography (HPLC)-gel filtration and dextran-coated charcoal adsorption.

We compared two binding assays for growth hormone binding protein (GHBP) measurements, which differ in the method of bound and free GH separation: HPLC-gel filtration or dextran coated-charcoal adsorption (DCC). Two pools of sera (high and medium GHBP activity) were used for quality-control assessment. Moreover, 62 samples from 34 children and 28 adults with different nutritional status were studied. Total, between- and intra-iodination coefficients of variation (CVs) from the two methods were not different. Although percentage binding measured in the pool sera significantly differed, the concentrations assessed by Scatchard plot were comparable. Results obtained by the two methods in the 62 sera were significantly correlated (r = 0.77, P < 0.001). With both methods GHBP activity correlated with chronological age and body mass index (BMI) and differed among groups with different nutritional status. Although HPLC and DCC separation methods for GHBP measurement differ in their practicability, our study demonstrates that performance and the clinical usefulness of the two methods are comparable.

Adolescent↗
PubMed1997

Influence of the volume of osteonecrosis on the outcome of core decompression of the femoral head.

OBJECTIVES: To assess the outcome of core decompression in the treatment of osteonecrosis of the femoral head related to the volume of necrotic bone measured according to a previously reported method. METHODS: Twenty hips corresponding to strictly Ficat stage II underwent magnetic resonance imaging and the volume of necrotic bone was expressed as a percentage of the volume of the entire head measured on each slice. All hips underwent core decompression and the outcome was evaluated at 24 months. The primary evaluation criterion was radiological appearance: the outcome was considered as good if the hip remained stage II and poor if the disease progressed. RESULTS: Twenty four months after core decompression, half the cases remained stable and in half the disease had progressed. Outcome seemed to be related to the volume of necrotic bone (average 22% in the good outcome group versus 45% in the poor outcome group (p = 0.0051)) and was independent of risk factors, age, and histological type. CONCLUSIONS: The volume of necrotic bone should be taken into account in the evaluation of any treatment, bearing in mind that in more than one third of cases this volume will probably decrease, especially at the beginning of the disease process.

Adult↗
PubMed1996

Skeletal matrices, muci, and the origin of invertebrate calcification.

The sudden appearance of calcified skeletons among many different invertebrate taxa at the Precambrian-Cambrian transition may have required minor reorganization of preexisting secretory functions. In particular, features of the skeletal organic matrix responsible for regulating crystal growth by inhibition may be derived from mucous epithelial excretions. The latter would have prevented spontaneous calcium carbonate overcrusting of soft tissues exposed to the highly supersaturated Late Proterozoic ocean [Knoll, A. H., Fairchild, I. J. & Swett, K. (1993) Palaios 8, 512-525], a putative function for which we propose the term "anticalcification." We tested this hypothesis by comparing the serological properties of skeletal water-soluble matrices and mucous excretions of three invertebrates--the scleractinian coral Galaxea fascicularis and the bivalve molluscs Mytilus edulis and Mercenaria mercenaria. Crossreactivities recorded between muci and skeletal water-soluble matrices suggest that these different secretory products have a high degree of homology. Furthermore, freshly extracted muci of Mytilus were found to inhibit calcium carbonate precipitation in solution.

Journal Article↗
PubMed1996

Calcification of the transverse ligament of the atlas in chondrocalcinosis: computed tomography study.

OBJECTIVE: To seek an association between articular chondrocalcinosis (AC) and calcification of the transverse ligament of the atlas (TLA), and to evaluate the frequency and the main computed tomography appearances of such calcification. METHODS: Axial computed tomography slices of the cervico-occipital hinge were performed routinely in 21 patients with AC (three men, 18 women; mean age 79 years, range 67-87) and compared with those from a control group of 21 age and gender matched patients without AC. RESULTS: Calcification of the TLA was present in 14 of the 21 patients (66%) in the AC group and in none of the 21 patients (0%) in the control group (chi 2 test: p < 0.001). Calcification was localised behind the odontoid process, inserted upon the osseous tubercles of the lateral masses of C1, and had a curvilinear profile; it varied in height (1.5 to 9 mm) and appearance (thin = < 1 mm; thick = > 1 mm) and formed either a single or a double band. CONCLUSION: This study has demonstrated a relationship between AC and calcification of the TLA. Although such calcification often remains asymptomatic (nine of 14 patients in our study), it may be associated with attacks of acute neck pain with segmentary stiffness, fever, and an increased erythrocyte sedimentation rate, sometimes revealing AC.

Aged↗
PubMed1995

Immunocytochemical localization of basic fibroblast growth factor in the human pituitary gland.

The immunocytochemical localization of basic fibroblast growth factor (bFGF) was studied in the human pituitary gland using a polyclonal antibody against fraction 1-24 of bovine recombinant bFGF. From a technical perspective, methacarn-fixed tissues were associated with a better preservation of bFGF immunoreactivity. Basic FGF-immunopositive glandular secretory cells were detected from the fetal period to adulthood in the pars distalis. No bFGF-positive cells were found in the neural lobe, basophil invasion areas, pars tuberalis or the walls of the pituitary cleft in the fetal pituitaries where this area was available. Endothelial cells and the axons of the neurohypophysis appeared weakly immunopositive or immunonegative depending on the fixative. According to their morphology, distribution, and the serial section analysis with all the pituitary hormones and vimentin, a folliculostellate cell marker, we conclude that bFGF-positive cells appear to be somatotropes. These results are consistent with the interpretation that bFGF plays a paracrine role in the modulation of the synthesis and secretion of various pituitary hormones.

Aged↗
PubMed1994

Patterning of the embryonic avian midbrain after experimental inversions: a polarizing activity from the isthmus.

Rostrocaudal inversions of the prospective midbrain (accompanied in some cases by other adjacent neuroepithelial zones) were performed in the neural tube of 2-day-old chick embryos in the form of autografts or quail/chick chimeras, involving both alar and basal plates. These experiments aimed to analyze causally the histogenetic rostrocaudal patterning of the midbrain, formed normally by diverse neuronal complexes. The experimental embryos were processed for study of the resulting cytoarchitecture or for study of the Engrailed-2 gene expression pattern. The exclusive inversion of the prospective midbrain produced a normal midbrain. Joint inversion of prospective midbrain plus the prospective isthmocerebellar tissue gave rise to an ectopic isthmocerebellar complex plus a symmetric double-caudal midbrain; additionally, the prospective caudal diencephalon was induced to form a polarized isthmomesencephalic phenotype in substitution of the pretectum. All these regulation processes affected both the alar and basal plates. The changes in cytoarchitectural fate were preceded by correlated changes in the gradiental expression of the gene Engrailed-2. These results suggest that the polarized structural pattern of the midbrain is regulated by graded positional information derived from the caudally adjacent isthmocerebellar domain, which is probably a source of morphogens.

Animals↗
PubMed1993

Ubiquitin immunoreactivity in corticotrophs following glucocorticoid treatment and in pituitary adenomas.

Ubiquitin involved in nonlysosomal protein degradation was studied in 31 nontumorous pituitary glands and 133 pituitary adenomas by immunocytochemical techniques. Normal nontumorous hypophyses were immunonegative for ubiquitin. Ubiquitin immunoreactivity was present in 3% to 30% of corticotrophs containing Crooke's hyaline in 10 of 12 glucocorticoid-treated patients. Fifty-eight adenomas showed ubiquitin-immunoreactive cells. Ubiquitin immunoreactivity was found in cytokeratin immunopositive filamentous inclusions of Crooke's cell adenomas and in fibrous bodies of somatotroph adenomas. Forty-five adenomas showed a diffuse cytoplasmic immunopositivity. No correlation was revealed between ubiquitin immunoreactivity, hormone content, and bromocriptine and octreotide treatments. The results are consistent with the interpretation that ubiquitin immunoreactivity in nontumorous corticotrophs containing Crooke's hyaline and in various adenomas is secondary to glucocorticoid excess or to altered metabolic activity. Whether ubiquitin expression reflects increased ubiquitin synthesis or decreased breakdown of ubiquitinated conjugates remains to be elucidated.

Adenoma↗
PubMed1992

Peptide binding to soluble HLA-DR4 molecules produced by insect cells.

HLA-DR4Dw4 molecules were expressed in insect Sf9 cells. The transmembrane and cytoplasmic domains of the DR4 alpha- and beta-chains were replaced by the carboxy terminal sequence of decay accelerating factor, leading to a phosphatidyl inositol glycan membrane anchor. This structure contains a cleavage site for phosphatidyl inositol-specific phospholipase C, allowing efficient solubilization of the rDR4 molecules. We present evidence that infected insect cells express properly associated surface heterodimers and are able to present antigenic peptides to DR4Dw4-restricted T cell clones. Phosphatidyl inositol-specific phospholipase-cleaved recombinant molecules exhibited in vitro binding characteristics similar to DR4 molecules purified from lymphoblastoid cells. In terms of peptide specificity, pH optimum, kinetics, and affinity they were indistinguishable within the limits of our assay system. However, the peptide binding capacity of the recombinant molecules was higher than that of native DR4 molecules.

Animals↗
PubMed1992

The pituitary gland in patients with breast carcinoma: a histologic and immunocytochemical study of 125 cases.

Pituitary glands obtained at autopsy of 125 women with disseminated breast carcinoma were studied to determine whether pituitary prolactin cell abnormalities (hyperplasia or adenoma) might be involved in the pathogenesis of breast carcinoma. In addition, we studied 85 pituitary glands obtained from unselected, consecutive autopsies in women without breast carcinoma but who died of other diseases (control group). The frequency of lactotroph hyperplasia was slightly higher in patients with breast carcinoma than in the control group, but the difference was not statistically significant, nor were differences in the frequency and size of pituitary adenomas, prolactin-producing or otherwise. No correlation was found between the presence of lactotroph hyperplasia or prolactin-producing adenomas (or both) and such factors as the patient's age, bilaterality of the carcinoma, previous treatment with tamoxifen citrate or oophorectomy, stage of disease, or survival. The frequency of breast carcinoma metastatic to the pituitary gland was higher in the study group than in the control group; however, the difference was not statistically significant. No preferential site of metastatic involvement in the pituitary gland was noted. Relative proportions of other lesions such as infarcts, cysts, lymphocytic infiltrates, and basophilic invasion were similar in the study and control groups. This study indicates that accumulation of prolactin cells, whether hyperplastic or adenomatous, cannot be considered a major risk factor for the genesis or progression of breast carcinoma.

Adenoma↗