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Biomedical subjects

F Léger

Publications and source records attributed to F Léger.

26 records · Page 2Linked to original sources
PubMed1986

Characterization of androgen receptors in normal and malignant human prostatic tissues.

The aim of this work was to study the physico-chemical characteristics of androgen receptors of normal and malignant human prostatic tissues. Association (k+1) and dissociation (k-1) rate constants and sedimentation profiles on sucrose density gradients were determined on [3H]androgen receptor complexes. In the presence of 20 mM sodium molybdate, no significant difference in k+1 and k-1 values could be found between cytosolic receptor preparations from normal and malignant specimens. The values obtained for k+1 (mean +/- SD) were 5 +/- 2 X 10(6)M-1 min-1 (N = 3) and 5 +/- 2 X 10(6)M-1 (N = 5); k-1 values of 23 +/- 4 X 10(-4) min-1 (N = 4) and 25 +/- 3 X 10(-4) min-1 (N = 5) were obtained for normal and malignant tissues respectively. Similar Nmax values were also obtained for normal [(mean +/- SD) 26 +/- 10 fmol/mg cytosolic protein (N = 5)] and malignant [20 +/- 9 fmol/mg protein (N = 7)] tissues. A statistically significant difference was found however, between k-1 values measured on [3H]androgen receptor complexes of nuclear extracts; values of 15 +/- 3 X 10(-4) min-1 (N = 4) and 9 +/- 1 X 10(-4) min-1 (N = 6) were found for normal and malignant tissue preparations respectively. This was also accompanied by a higher level of androgen receptors in nuclear extracts of malignant [Nmax, 308 +/- 171 fmol/g of tissue (N = 8)] compared to normal [Nmax, 68 +/- 11 fmol/g of tissue (N = 5)] tissues. The cytosolic [3H]androgen receptor complexes prepared from normal tissues sedimented mainly in the 8-9S area on sucrose density gradient whereas those from malignant tissues sedimented 50% in the 8-9S area and 50% in the 4S area. In conclusion, in this study, we found a different sedimentation profile of androgen-receptor complexes from the cytosol of prostatic cancers compared to normal as well as a diminution of their dissociation rate constant in nuclei.

Cell Nucleus↗
PubMedDate not supplied

[Biocompatibility of hydroxypropylmethylcellulose as a vitreous substitute in rabbits].

We have studied the biocompatibility of the hydroxypropylmethylcellulose in ten rabbits' eyes after lensectomy and posterior vitrectomy. In seven eyes the inflammatory reaction was severe. The reason why the hydroxypropylmethylcellulose is biocompatible in the anterior segment and not in the vitreous body seems to be explained by its quantity and its concentration in the eye at the end of the surgical procedure.

Animals↗
PubMedDate not supplied

Diprosopia revisited in light of the recognized role of neural crest cells in facial development.

OBJECTIVE: The aim of this study is to compare the theory of embryogenesis of the face with human diprosopia. This peculiar form of conjoined twinning is of great interest because 1) only the facial structures are duplicated and 2) almost all cases have a rather monomorphic pattern. The hypothesis is that an initial duplication of the notochord leads to two neural plates and subsequently duplicated neural crests. In those conditions, derivatives of the neural crests will be partially or totally duplicated; therefore, in diprosopia, the duplicated facial structures would be considered to be neural crest derivatives. If these structures are identical to those that are experimentally demonstrated to be neural crest derivatives in animals, these findings are an argument to apply this theory of facial embryogenesis in man. METHODS: Serial horizontal sections of the face of two diprosopic fetuses (11 and 21 weeks gestation) were studied macro- and microscopically to determine the external and internal structures that are duplicated. Complete postmortem examination was performed in search for additional malformations. RESULTS: The face of both fetuses showed a very similar morphologic pattern with duplication of ocular, nasal, and buccal structures. The nasal fossae and the anterior part of the tongue were also duplicated, albeit the posterior part and the pharyngolaryngeal structures were unique. Additional facial clefts were present in both fetuses. Extrafacial anomalies were represented by a craniorachischisis, two fused vertebral columns and, in the older fetus, by a complex cardiac malformation morphologically identical to malformations induced by removal or grafting of additional cardiac neural crest cells in animals. CONCLUSION: These pathological findings could identify the facial structures that are neural crest derivatives in man. They are similar to those experimentally demonstrated to be neural crest derivatives in animals. In this respect, diprosopia could be considered as the end of a spectrum, whereas the other end is agnathia-holoprosencephaly complex. This assumption has to be discussed, but we want to draw attention to the fact that diprosopia must not be considered as a curious form of conjoined twinning, but as a major means of bringing us a better knowledge of the facial embryogenesis in man.

Abnormalities, Multiple↗
PubMedDate not supplied

Pathologic correlations between ocular and cerebral lesions in 36 AIDS patients.

The eyes and brain have rarely been studied simultaneously in AIDS patients. We have examined both the eyes and brain of 36 patients autopsied these past 3 years. Ten cases had concomitant involvement of eyes and brain by the same pathology: cryptococcus neoformans in 1, aspergillus in another, cytomegalovirus (CMV) infection in 5, and B cell lymphomas in 2 (1 patient had the last 2 disorders associated). One patient presented pericapillary microhemorrhages in the retina of the left ocular globe as well as in the right occipital lobe. Six other patients had isolated CMV retinopathy and 4 others had B cell cerebral lymphomas. Eleven patients with foci of cerebral toxoplasmosis did not have visible cysts of toxoplasma gondii in their retina, in agreement with the other series devoted to the concomitant study of the eyes and brain in AIDS patients. On the other hand, their simultaneous involvement in an AIDS patient must first point to CMV infection.

AIDS Dementia Complex↗