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J Casanova

Publications and source records attributed to J Casanova.

At least 19 recordsLinked to original sources
PubMed1992

Localization of endoderm-specific mRNAs in differentiating F9 embryoid bodies.

Primitive endoderm in the peri-implantation mouse embryo differentiates into two separate lineages, visceral and parietal endoderm (VE and PE). F9 teratocarcinoma cells, when grown in suspension in the presence of retinoic acid (RA), differentiate into embryoid bodies (EBs) which can be used as a model system to study the spatially appropriate induction of VE- and PE-specific gene expression. We have used a whole mount in situ hybridization technique to follow the localization of VE-specific AFP and PE-specific tPA mRNAs during EB differentiation. We show that the putative endoderm-specific markers are localized to the endoderm in mature EBs, and that AFP mRNA is localized to the apical edge of the VE in RA EBs. Surprisingly, prior to localization of endoderm-specific markers at the periphery of EBs, these genes are expressed at low to moderate levels in all cells of the EB. Our data suggest that the establishment of endoderm in EBs is position dependent and not the result of sorting out of predetermined, randomly distributed cells. Our observations also suggest a two-step process for establishing endoderm-specific gene expression, involving up-regulation of transcripts throughout the EB prior to the restriction of their expression to the outer differentiating cell layer.

Animals↗
PubMed1992

Corpus cavernosum invasion and tumor grade in the prediction of lymph node condition in penile carcinoma.

Of the 101 patients with penile cancer, we have analyzed 66 from whom we had enough information: 42 (63.3%) patients with corpora cavernosa invasion (T2-3) and 24 (36.6%) without (T1). With respect to the tumor grade, in 36 (54.3%) patients it was well differentiated (G I), in 23 (34.8%) moderately (G II) and in 7 (10.6%) poorly differentiated (G III). We also analyzed the inguinal lymph node condition. Of the 66 patients, 28 (42.4%) developed nodal metastases, and 38 (57.6%) were considered free of nodal metastases and disease with an average follow-up of 76.2 months (range 38-192). The presence of metastatic nodes was influenced by both tumor stage and grade with significant differences between T2-3 and T1 (p = 0.001) and between G II-III and G I (p < 0.01), but each of them alone was not a sufficiently reliable predictive factor. In order to associate local stages and tumor grades in relation to the presence of metastatic nodes, we checked that none of the patients with T1, G I (group 1) developed nodal metastases, and therefore, 'wait and see' should be the suitable approach. Twenty (80%) of the patients with T2-3, G II-III (group 2) developed metastatic lymph nodes, thus, in this group, an early lymphadenectomy should be performed. In the remaining 22 patients with T1, G II-III and T2, G I (group 3), 8 (36.4%) showed metastatic lymph nodes; in this group, other factors such as age, cultural level and obesity should be taken into account when deciding on lymphadenectomy.

Adult↗
PubMed1992

Half-site spacing and orientation determines whether thyroid hormone and retinoic acid receptors and related factors bind to DNA response elements as monomers, homodimers, or heterodimers.

The receptors for thyroid hormone (T3R) and retinoic acid (RAR) are members of a nuclear receptor subfamily that are capable of recognizing similar DNA sequences. Native response elements for T3R and RAR consist of two or more putative half-site binding motifs organized as imperfect direct or inverted repeats separated by different sized nucleotide gaps. To clarify how T3R, RAR, and related factors recognize DNA response elements, we analyzed the interaction of purified receptors with a series of inverted and direct repeats of an idealized AGGTCA half-site separated by different sized nucleotide gaps. Our results indicate that RAR and T3R can bind to half-sites as monomers and, depending on the orientation and distance between half-sites, also bind as homodimers or T3R-RAR heterodimers. T3R also binds to certain DNA elements as a heterodimer with one or more nuclear factors from eucaryotic cells. Thus, the orientation and spacing of half-sites play a central role in determining which configuration of receptors and nuclear factors will interact with a specific DNA element. This along with the ability of these factors to participate in reversible protein-protein interactions serve to broaden and diversify the responses mediated by T3R, RAR, and related members of this nuclear receptor subfamily.

Base Sequence↗
PubMed1991

Interaction between torso and dorsal, two elements of different transduction pathways in the Drosophila embryo.

Early development of the Drosophila embryo is under the control of some maternal genes responsible for the establishment of its general pattern. Three sets of genes determine the anteroposterior pattern; two distinct systems specify anterior and posterior development and a third one, the terminal system, is responsible for the development of the poles of the embryo. A different set of genes specifies dorsoventral polarity, which is established by the graded activity of the dorsal gene product. Here I analyze the effect of the terminal system on the expression of two zygotic genes involved in dorsoventral pattern, snail and decapentaplegic, and I show that this effect is mediated by a reduction on dorsal activity by the terminal system. Due to the interaction of these two systems, both of which use transmembrane signalling mechanisms, the poles adopt a more dorsalized fate than their counterparts in the middle of the embryo.

Animals↗
PubMed1991

"Nintendinitis".

Explore the source record for details and available documents.

Child↗
PubMed1991

Ridge detection tactility deficits associated with carpal tunnel syndrome.

A ridge detection threshold task was administered to patients diagnosed as having carpal tunnel syndrome for studying performance in an occupationally relevant functional tactile inspection task. Thresholds were compared with a reference group of subjects not having carpal tunnel syndrome symptoms, performing the same task. The threshold detection task used the method of limits for studying the effects of carpal tunnel syndrome, rate of ridge height changes, ridge gradient, and direction of shearing against the skin on ridge detection thresholds for a repeated measures factorial experimental design. Sixteen carpal tunnel syndrome hands and 30 normal hands were studied. Average ridge detection threshold was 0.08 mm for the normal subjects and increased to 0.20 mm for the carpal tunnel syndrome subjects. No significant age effect was observed. These results suggest that workers having carpal tunnel syndrome may not detect an edge or surface defect in a tactile inspection task unless it was more than twice as high as detected by workers without CTS.

Adult↗
PubMed1991

Purification, characterization, and localization of aspartoacylase from bovine brain.

Canavan disease, an autosomal recessive disorder, is characterized biochemically by N-acetylaspartic aciduria and aspartoacylase (N-acyl-L-aspartate amidohydrolase; EC 3.5.1.15) deficiency. However, the role of aspartoacylase and N-acetylaspartic acid in brain metabolism is unknown. Aspartoacylase has been purified to apparent homogeneity with a specific activity of approximately 19,000-20,000 nmol of aspartate released/mg of protein. The native enzyme is a 58-kDa monomer. The purified aspartoacylase activity is enhanced by divalent cations, nonionic detergents, and dithiothreitol. Low levels of dithiothreitol or beta-mercaptoethanol are required for enzyme stability. Aspartoacylase has a Km of 8.5 x 10(-4) M and a Vmax of 43,000 nmol/min/mg of protein. Inhibition of aspartoacylase by glycyl-L-aspartate and amino derivatives of D-aspartic acid suggests that the carbon backbone of the substrate is primarily involved in its interaction with the active site and that a blocked amino group is essential for the catalytic activity of aspartoacylase. Biochemical and immunocytochemical studies revealed that aspartoacylase is localized to white matter, whereas the N-acetylaspartic acid concentration is threefold higher in gray matter than in white matter. Our studies so far indicate that aspartoacylase is conserved across species during evolution and suggest a significant role for aspartoacylase and N-acetylaspartic acid in normal brain biology.

Amidohydrolases↗
PubMed1991

Recurrence of superficial bladder tumors in prostatic urethra.

Of our 276 patients with superficial bladder carcinoma, 242 were male, and 36 of these had recurrence in prostatic urethra, 26 with macroscopic tumors, and 10 with tumors in situ (TIS). These recurrences represent an incidence of 13.3%, with an average follow-up of 34.3 months. When the urethral tumor was limited to the mucosa, we chose conservative therapy, and the patients entered a random program with Mitomycin or Adriamycin administered endovesically. With this program, we could control the disease in 59.3% of the patients. However, 22.2% of them had recurrence with prostatic stromal infiltration, so that we performed a more exhaustive exploration of the prostate, taking biopsies not only at the 5 and 7 o'clock positions, but also making a wider resection in order to find the incipient infiltration of the prostatic stroma, and trying to avoid a possible understaging. When the urethral tumor had infiltrated the prostatic stroma, we performed cystoprostatourethrectomy, getting a survival rate free of disease of 40%. An association with vesical TIS was detected in 61.1% of these patients, with terminal ureteral tumor in 8.3% and with the anterior urethra in 11.1%, showing the diffuse pattern of the disease. We conclude that when recurrence of prostatic urethra is present, it is necessary to monitor the whole urothelium during follow-up.

Administration, Intravesical↗
PubMed1991

Carcinoma in situ associated with superficial bladder tumor.

In a sample of 306 patients with superficial bladder tumors (Ta, Tl), 48 were affected by associated carcinoma in situ (TIS). We included 40 of them in a random program with Mitomycin C or Adriamycin, administered endovesically. We found that those patients with associated TIS whose progression rate had increased to 37.1% compared to 8.8% in the original series (p less than 0.01), had a worse prognosis. Besides, 10 of them required radical cystectomy. With this chemotherapy program, we achieved a high rate of complete response (70%), but its duration was limited by a recurrence rate of 42.9%, with a time free of disease of 26.2 months. In the whole group, the survival rate free of disease was 77.5%, with an average follow-up of 37.3 months. On the other hand, we found extravesical recurrences not only in the prostatic urethra (13; 32.5%) but also at the end of the ureter (3; 7.5%).

Actuarial Analysis↗
PubMed1990

Different forms of Ultrabithorax proteins generated by alternative splicing are functionally equivalent.

The Ubx gene of Drosophila normally produces several forms of Ubx proteins through alternative splicing of two microexons. We describe here two new viable Ubx mutations that show similar and almost wild-type adult phenotypes. Molecular characterization has shown that one of them, UbxMX17, is an inversion within the Ubx transcription unit including one of the microexons involved in alternative splicing. This results in mutant flies possessing a very abnormal array of Ubx proteins, probably including spliced forms not present in wild-type flies. Yet these protein products successfully substitute for the normal ones and allow virtually normal Ubx function. We argue that the different Ubx proteins are developmentally equivalent and that the slight mutant phenotype observed in UbxMX17 flies is not due to the abnormal set of Ubx proteins but to a breakpoint in a cis-regulatory region.

Animals↗
PubMed1990

The homeodomain protein, Pit-1/GHF-1, is capable of binding to and activating cell-specific elements of both the growth hormone and prolactin gene promoters.

Studies were conducted to determine whether the trans-acting protein Pit-1/GHF-1 can bind to and activate promoter elements in both the GH and PRL genes that are necessary for cell-specific expression. Four pituitary cell lines that differentially express the endogenous GH and PRL genes were examined for their ability to activate GH and PRL promoter constructs containing sequences necessary for cell-specific expression (CSEs). Plasmids containing one CSE, -96 PRL and -104 GH, were similarly expressed in each of the four cell lines. Of the plasmids containing two CSEs, -173 PRL was always activated to a greater extent than -145 GH, with this relative activation being stronger in GC and GH1 cells than in 235-1 and GH4C1 cells. Protein-DNA binding assays were used to show that the GH and PRL CSEs specifically bound two highly abundant nuclear proteins (31 and 33 kDa). The two proteins were present at similar levels in all four pituitary cell lines and were recognized by a Pit-1/GHF-1 antibody. In contrast, HeLa and Rat2 cells did not activate transfected GH or PRL plasmids and did not contain nuclear proteins that specifically bound to the GH and PRL CSEs. However, cotransfection of these cells with the expression vector RSV-Pit-1/GHF-1 resulted in the activation of -173 PRL and -145 GH (PRL greater than GH). HeLa cells transfected with RSV-Pit-1/GHF-1 also contained 31- and 33-kDa nuclear proteins that bound to the GH and PRL CSEs. These results show that Pit-1/GHF-1 is present at levels in pituitary cell lines that are sufficient to activate the minimal elements in both the GH and PRL promoters necessary for cell-specific expression of these genes.

Animals↗
PubMed1990

Pattern formation under the control of the terminal system in the Drosophila embryo.

The specification of the most anterior and posterior domains of the Drosophila embryo depends on the activity of the torso protein, a putative tyrosine kinase receptor. Localized torso activity at the poles of the embryo generates graded information that specifies distinct portions of the body. The primary response to the terminal signal in the posterior end of the embryo is likely to be the activation of the gap genes huckebein and tailless. Here I address the question of how the graded maternal signal generates different elements of the pattern at the posterior end of the embryo and what role huckebein and tailless activities may play in this process. These experiments show that distinctly localized activities of huckebein and tailless are responsible for the appropriate expression of other genes known to be under the control of the terminal system. Moreover, they suggest that different elements of the terminal pattern can be specified in response to distinct levels of graded tailless activity.

Animals↗
PubMed1990

Expression and regulation of the abd-A gene of Drosophila.

We have developed a specific polyclonal antibody that recognizes the protein products of the abdominal-A (abd-A) gene, a member of the bithorax complex of Drosophila. The normal expression domain extends from parasegments 7 to 13, in good correspondence with previous genetic and molecular results. However, while the anterior border of expression is precisely demarcated by a parasegmental boundary, the posterior border does not coincide with a lineage boundary. Within the normal domain, the expression of abd-A shows intrametameric modulation; the amount of product is higher in posterior compartments and in the most anterior cells of the anterior compartments and then gradually decreases. We have examined the effect on abd-A expression of a number of mutations, some mapping within and others outside the abd-A transcription unit. Those mapping to the transcription unit eliminate or severely reduce the amount of abd-A antigen, while those mapping outside produce an abnormal distribution of abd-A protein. Finally, we show that the abd-A gene is down-regulated in part of the Abdominal-B (Abd-B) domain, precisely in those regions where the Abd-B gene is expressed at high levels.

Animals↗
PubMed1989

Structure and function of the bithorax complex genes of Drosophila.

The bithorax complex consists of three genes, Ubx, abd-A and Abd-B, which together specify the characteristic development of parasegments 5 to 13 of Drosophila. These genes are structurally homologous; they are of similar size, are transcribed in the same orientation and they all have a homeobox near the 3' end of their transcription unit. Genetic and molecular analyses of Ubx suggest that the gene contains one transcription unit encoding the protein products and at least three cis-regulatory regions. Two of these, abx and bxd, promote the activity of the Ubx transcription unit to the levels appropriate for parasegments 5 and 6, respectively. A third regulatory element, called Cbx-like, prevents the expression of Ubx anterior to parasegment 5. The gene abd-A is not as well known, but genetic and molecular studies indicate at least one cis-regulatory region downstream of the 3' end of the transcription unit. In the gene Abd-B there are two distinct trans-acting elements, called m and r. The m element is a conventional homeotic function, which specifies the identity of parasegments 10 to 13. The r element is specific for parasegment 14 where it suppresses a number of homeotic functions (including m). Molecular analysis indicates that Abd-B contains two transcription units with a common 3' end which correspond to the m and r elements defined genetically.

Animals↗