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C Illueca

Publications and source records attributed to C Illueca.

12 recordsLinked to original sources
PubMed2002

[Idiopathic granulomatous hypophysitis. Morphological and immunohistochemical study of a case].

Inflammatory diseases of the pituitary gland constitute a group of interest because of their scarce frequency, because the disorder presents with symptoms of hypopituitarism and expanding sellar mass and because of their therapeutics implications. We present one case of idiopathic granulomatous hypophysitis, in a 55-years-old patient with daily headaches, panhypopituitarism and a sellar mass lesion. Granulomatous hypophysitis is characterized by granulomas with epithelioid histiocytes and multinucleated giant cells but also shows lymphocyte collections. With respect to immunohistochemistry our results show histiocytes (CD68+) and an heterogeneous inflammatory infiltrate (CD45RO+ y CD20+). We analyze the differential diagnosis with another granulomatous processes, infectious or not infectious, and with the histiocytosis. We examine the possible relation with the lymphocytic hypophysitis.

Anti-Inflammatory Agents↗
PubMed2000

Prognostic factors in Barrett's esophagus: an immunohistochemical and morphometric study of 120 cases.

UNLABELLED: Barrett's esophagus is a condition in which the squamous mucosa that normally lines the distal esophagus is replaced by a columnar type of epithelium. Although it carries a clear risk of adenocarcinoma, the estimation of this risk and therefore the value of endoscopic screening remain highly controversial. AIM: To investigate more sensitive techniques to identify those patients who are at high risk of developing cancer and who need intensive endoscopic surveillance for early detection. METHODS: A morphologic, histochemical and morphometric study was performed on paraffin-embedded material from 120 patients with Barrett's esophagus and 18 with adenocarcinoma. In addition, each sample was analyzed immunohistochemically with proliferating cell nuclear antigen (PCNA), p53, c-erbB-2, CEA and EMA antibodies. RESULTS: In all zones of the glandular mucosa we found a higher percentage of PCNA-positive nuclei when the specialized epithelium was present. We saw PCNA expression in 75% of the patients with adenocarcinoma, and p53 expression in 15% of the patients without dysplasia, 37% of the patients with dysplasia and 44% of the patients with adenocarcinoma. Positivity for c-erbB-2 was found in 38% of the patients without dysplasia, 53% of those with dysplasia and 37% of those with adenocarcinoma. Aneuploidy was found in 70% of the patients with metaplasia or dysplasia and in all patients with adenocarcinoma. CONCLUSIONS: We conclude that p53, PCNA overexpression and aneuploidy are markers of risk for malignancy in Barrett's esophagus.

Adenocarcinoma↗
PubMed1998

Diagnostic value of CD34 immunostaining in desmoplastic trichilemmoma.

Desmoplastic trichilemmoma (DT) is a variant of trichilemmoma, characterized by a central prominent desmoplastic component which may simulate invasive carcinoma. We have studied the morphologic and immunohistochemical features of seven cases of DT. Immunohistochemistry was performed on paraffin sections using monoclonal antibodies to CD34 (QBEND/10), vimentin and GCDFP-15. CD34 was also tested in seven cases of basal cell carcinoma (BCC), three with outer root sheath differentiation and four with morphea-form features, and five squamous cell carcinomas. Histologically, features of conventional trichilemmoma were seen at the periphery of the seven lesions. In contrast, at the center, the epithelial cells tended to cluster in narrow irregular cords and nests entrapped in a dense collagenous stroma. One case of DT coexisted with a BCC. In all cases of DT, epithelial tumor cells showed CD34 immunostaining. All cases of BCC, including the one contiguous to a DT, were CD34 negative. CD34 immunodetection in the epithelial cells of the pseudoinvasive component of DT may be of great value in the differential diagnosis with other desmoplastic tumors of the skin, and particularly with BCC.

Aged↗
PubMed1998

The use of Newton's rings for characterising ophthalmic lenses.

The interference technique of Newton's Rings is widely used for the quality control of optical surfaces because the precision obtained with this method proves to be very satisfactory. The dimensions of the rings permits calculation of the radii of curvature of the analysed surfaces and deformation of the interference pattern can be utilised to calculate other parameters, such as astigmatism. We describe the study of progressive surfaces by means of this technique, whereby the analysis of the various points of the progressive corridor is made, and also include information on the power function for these lenses, as well as the addition and corridor length.

Lenses↗
PubMed1997

Erythrophagocytic tumour cells in melanoma and squamous cell carcinoma of the skin.

AIMS: Erythrophagocytosis is a characteristic feature of tumour cells in malignant histiocytosis, some leukaemias, lymphomas, and also reactive histiocytes in the haemophagocytic syndrome associated with a variety of infections and neoplasms. It has also been found exceptionally in metastatic malignant epithelial cells in bone marrow and lymph nodes. We present two cases, a cutaneous malignant melanoma and an acantholytic squamous cell carcinoma, in which erythrophagocytosis by tumour cells was demonstrable by both light and electron microscopy. METHODS AND RESULTS: The melanocytic and squamous nature of these cells was supported by the immunohistochemical detection of HMB45, S100, and NKI-C3 in the former, and cytokeratin and EMA in the latter, and at ultrastructural level by the presence of melanosomes and tonofilaments, respectively. CONCLUSIONS: This is, to our knowledge, the first documented report of erythrophagocytic tumour cells in human melanomas and primary carcinomas. Biological considerations apart, this unusual feature can prove to be of value to avoid a misdiagnosis of a variety of haematopoietic malignancies.

Aged↗
PubMed1996

The effect of pupil and observation distance on the contrast sensitivity function.

Measuring the contrast sensitivity function (CSF) is becoming more frequent in the analyses that are routinely done in optometric practice. This measurement is generally done in far vision, and the observation distance and its effects are not considered to significantly alter this function. Among these effects we should point out the accommodation of the visual optical system to the stimulus and the errors in accommodation associated with this, changes in pupil diameter and therefore in retinal illumination when the observation distance changes, the different level of aberrations (spherical aberration, astigmatism) for different cases, and so on. All of these factors contribute to the fact that the contrast sensitivity of a visual system varies according to the accommodative stimulus. In this study we attempt to clarify the influence of these different parameters by evaluating the CSF for three observation distances. The study was done in monocular vision, with a natural pupil and with a 3 mm artificial pupil that made it possible to maintain the same level of retinal illumination for all distances.

Accommodation, Ocular↗
PubMed1995

Influence of contrast on the recognition of defocused letters: a geometrical model.

We show how contrast (C) affects the recognition of defocused letters. To do this, the maximum distance (threshold distance) at which a subject, with an induced refraction of -5.5 D, can recognize a letter was determined. Our results show that when C = 1, the recognition threshold distance is such that the ratio eta/xi, between the pseudoimage of the letter (eta) and the blur circle (xi), corresponding to any point of the letter at this distance is about eta/xi = 2; the exact value depends on the difficulty of recognition, in agreement with previous experiments. This ratio represents the sharpness of the image in a geometrical treatment of image formation, providing a geometrical criterion for recognition. Reduction in contrast can be compensated by improving the geometrical sharpness; i.e. bringing the object closer to the subject's are point. Our results show that the increment of eta/xi as a function of the contrast is between C = 0.1 and 1.0. We suggest that a similar geometrical criterion for recognition could be used for any contrast (at least down to C = 0.1 and defocus > 1 D), provided that the proper value of eta/xi is used in each case. On this basis we propose a purely geometrical model, which agrees well with the data and predicts the relationships between tolerance to defocus, contrast and visual acuity; including the well-known relation between visual acuity and defocus when contrast is unity.

Contrast Sensitivity↗
PubMed1994

Variation of the visual acuity--luminance function with background colour.

The relationship between visual acuity (VA) and background colour is a question that still creates a certain amount of confusion even today, although most authors agree that colour background does not basically affect VA, or at best, values that are only slightly better are obtained with monochromatic yellow light. The object of this paper is to try to clarify if, when the axial chromatic aberration (ACA) has been compensated for, certain differences due exclusively to colour persist or not. In order for this, the VA-luminance functions with red, green, blue and white backgrounds have been measured for two emmetropic observers, before and after compensating for the ACA. The results show that after the compensation, the curve corresponding to red is above the one corresponding to blue, with the one corresponding to green in between. The achromatic function (white background) practically overlaps with the green one. This behaviour is consistent with that shown recently for contrast sensitivity functions (CSFs). However, the asymptotic values are identical for the three colours, and so, it is understandable that no significant differences are normally found when only a standard measurement of VA is taken using the typical illumination from an optotype projector.

Adult↗
PubMed1992

Vision defects in albinism.

We have examined the possible presence of color vision anomalies in 9 individuals (17 eyes, 1 blind) with fundus findings suggesting ocular albinism using the Ishihara plates, the 28-hue Roth test, and the Davico anomaloscope. Results indicate that four of these individuals show no sign of the anomalies expected in an albino in either of the two eyes. Of the remaining cases, two are simple deuteranomals in both eyes, according to Pickford's classification criteria. The rest have protanomaly; however, in these the deviation toward red appears in both eyes in only one subject, whereas in the other two subjects it appears in only one eye, their binocular color vision being basically normal. Our study shows that a large proportion of these albinos have photophobia, pendular nystagmus, strabismus, noticeable refractive errors (astigmatism and high myopia), and poor visual acuity [usually less than 6/30 (20/100) with correction]. The measurement of contrast sensitivity function (CSF) indicates that the frequency of 12 cpd cannot be perceived, even in binocular vision.

Adolescent↗
PubMed1992

Focimeter measurement of the astigmatism arising from oblique central refraction.

In this article, a method for measuring the astigmatism produced by an oblique central refraction is proposed. Measurements were taken using two different values of the pantoscopic angle that can be produced by lenses mounted in frames. We show that in specific cases, and as a function of the angle and power of the lens, the resulting astigmatism can surpass the tolerance level of the eye.

Lenses↗