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Biomedical subjects

F Sanchez

Publications and source records attributed to F Sanchez.

At least 55 records · Page 3Linked to original sources
PubMed1991

Differences in serum IgE antibody activity to benzylpenicillin and amoxicillin measured by RAST in a group of penicillin allergic patients.

To determine the influence of the acyl side chain on the IgE antibody specificity of the two most common penicillins inducing allergic reactions in our community, benzylpenicillin (BP) and amoxicillin (AX), IgE positive sera from a group of 24 patients allergic to penicillin were studied. RAST was determined in parallel to benzyl penicilloyl-polylysine (BPO-PLL) and amoxicilloyl-polylysine (AX-PLL) in each serum, and values greater than an established coefficient of variation of 15% were considered as different for either of the haptens used (BP and AX). 16 sera proved to be more positive to BP (Group A), six to AX (Group B) and in two IgE was positive to both haptens with a similar value (Group C). RAST titration concentration effect curves and RAST inhibition studies with a pool of sera from each group (A, B, C) and individual sera showed that most of them were more specific for either BPO or AX, a minority being of similar value to both. These findings indicate that the side chain structure of penicillins is relevant in the constitution of the antigenic determinant, although in some instances the common chemical structure of betalactam is recognised mainly by the IgE antibodies. The clinical relevance of these data needs to be established.

Amoxicillin↗
PubMed1991

A comparative analysis of the vasotocin and vasopressin systems in the chicken and rat hypothalamus. An immunocytochemical study.

By means of the peroxidase-antiperoxidase technique a comparative immunocytochemical study of the distribution of the vasotocin- and vasopressin-reacting system in the chicken and rat hypothalamus was carried out. In both species it is possible to distinguish, on the basis of their topographical location, three different comparable populations: The first one is situated very close to the pial surface and the optic chiasma (L1 and L2 groups in the chicken and the supraoptic nucleus in the rat). The second one is located near to the third ventricle and corresponds to the suprachiasmatic nucleus of both species and the periventricular groups of the chicken (P1, P2, and P3 groups) and the periventricular subdivision of the paraventricular nucleus of the rat. The third one is situated between the two previous populations and consists of small clusters of reacting neurons (L3 and L5 groups in the chicken and the nucleus circularis and fornicalis in the rat) and to a large cluster of reacting neurons (L4 group in the chicken and the magnocellular part of the paraventricular nucleus in rat). In the median eminence of the chicken the immunoreactive axons were located in the internal zone and the anterior part of the external zone. However in the rat, the reaction was exclusively located in the internal zone.

Animals↗
PubMed1990

Morphometric changes of specific located vasopressin-reacting parvicellular neurons in the paraventricular nucleus of the rat after adrenalectomy.

The morphological-morphometric consequences of bilateral adrenalectomy on vasopressin-reacting neurons of the paraventricular nucleus of the rat hypothalamus were analyzed. Bilateral adrenalectomy led to a dramatic increase in the cellular area as well as the number of immunoreactive cells (when compared to those obtained in normal colchicine-treated animals) in the neurons located in the anterior, medial and periventricular parvicellular subdivisions of the paraventricular nucleus. By contrast, no changes were observed in either the dorsal or lateral parvicellular subdivisions or in any of the magnocellular subdivisions of the paraventricular nucleus.

Adrenalectomy↗
PubMed1990

Morphometric study of immunoreactive GH-cells of the adenohypophysis of rats treated with Met-enkephalin.

Morphological and morphometric changes were found in adenohypophyseal GH immunoreactive cells after intraventricular administration of Met-enkephalin to adult rats of both sexes. Morphologically, following Met-enkephalin treatment, the males showed cells stained intensely and homogeneously in their cytoplasm, while the females showed cells with a weaker degree of staining and a cytoplasm with a granular aspect; previous administration of naloxone prevented the changes observed in the males and intensified the reaction in the females. Morphometrically, in all the groups of animals studied, the males showed a greater cellular area than the females, accompanied by a decrease in the cytoplasmic area but without significant differences in the nuclear area. Met-enkephalin in both sexes produced an increase in cellular area, accompanied by a significant increase in the cytoplasmic area and, although less manifest, in the nuclear area. Neither kind of change appeared when naloxone was administered prior to Met-enkephalin treatment.

Animals↗
PubMed1986

Hürthle cell and mitochondrion-rich cell tumors. A clinicopathologic study.

Hürthle cells are large eosinophilic thyroid cells that contain a large number of mitochondria with a high content of oxidative enzymes. In the last 10 years several reports have emphasized the disagreement over the morphologic features, biologic behavior and treatment of Hürthle cell tumors. The authors reviewed the clinical and pathologic features of 28 patients with Hürthle cell and mitochondrion-rich cell tumors (16 adenomas, 10 follicular carcinomas, and 2 papillary carcinomas) and present electron microscopic, immunohistochemical, and morphometric data. The results suggest that there is a correlation between biologic behavior and pathologic findings, that tumor size should not be considered a special conditioning factor in order to assign a biologic behavior, that nuclear size and anisokaryosis are not an absolute criteria for diagnosing malignancy, and finally, that electron microscopic examination is not useful in separating benign from malignant Hürthle cell tumors.

Adenocarcinoma↗
PubMed1986

Failure to visualise the abdominal portion of the inferior vena cava with computed tomography: a clue to underlying abdominal pathology.

Failure to visualise the intra-abdominal portion of the inferior vena cava (IVC) using contrast-enhanced computed tomography (CT) is unusual. A review of 1272 contrast-enhanced abdominal CT examinations revealed that the IVC was not visible at one or more levels in only 132 (10.4%). In 57 (43%), non-visualisation was due to pathological processes, most frequently metastatic carcinoma, causing compression or thrombosis of the IVC. In the remainder, technical factors or artefacts could explain the non-visualisation. Techniques and procedures to improve visualisation of the IVC are discussed. Failure to visualise the IVC on CT at any level unexplained by artefacts is abnormal.

Abdomen↗
PubMed1986

Differential diagnosis between follicular adenoma and follicular carcinoma of the thyroid by marker features.

Morphometric features descriptive of nuclear morphology, nuclear chromatin texture and nuclear staining density were studied in tissues from encapsulated follicular carcinoma and follicular adenoma of the thyroid, whose differentiation is one of the most difficult tasks in thyroid pathology. Measurements were made on nuclei in both tumorous and normal-appearing areas in the same section from six patients with each diagnosis, as well as on nuclei in sections from six normal individuals. The average nuclear optical density (OD) was significantly lower in the follicular carcinomas than in the follicular adenomas while the nuclear area was significantly increased in the carcinomas. The variance of the nuclear OD values was higher in both tumor and normal-appearing areas in the sections from the follicular adenomas than in the follicular carcinomas; this variance was lowest in tumor areas from the follicular carcinomas. There were also significant differences in another chromatin feature (the average difference in OD values between adjacent pixels) between nuclei from follicular carcinomas and those from follicular adenomas, whether comparing measurements between the tumor areas or between the histologically normal-appearing areas of the sections. These results suggest that the high-resolution study of marker features, such as nuclear chromatin and staining density, may help in the differentiation between follicular adenoma and encapsulated follicular carcinoma of the thyroid.

Adenocarcinoma↗
PubMed1985

Computed tomography evaluation of pheochromocytoma in pregnancy.

Two cases representative of the spectrum of the problem of pheochromocytoma in pregnancy are presented. One patient was typical of many cases of pheochromocytoma not diagnosed until delivery, with resultant maternal and fetal death. Computed tomography accurately preoperatively localized a pheochromocytoma involving the organ of Zuckerkandl in the second patient, with subsequent uncomplicated removal of the tumor during a cesarean delivery. A discussion of pheochromocytomas in pregnancy and the relative risk and benefits of preoperative localization with computed tomography are presented.

Adrenal Gland Neoplasms↗
PubMed1983

In vitro transcription of Drosophila actin and 70,000-dalton heat shock protein genes.

Drosophila genomic DNAs containing a chromosomal locus 87C1 70,000-dalton heat shock protein gene, the locus 79B actin gene, and the 88F actin gene have been used as templates in an in vitro HeLa transcription system. RNA polymerase II-dependent transcription initiates from specific sites on the heat shock protein gene and the 79B actin gene. The locations of the transcription start sites were determined by two types of experiments: sizing of RNA runoff transcripts and S1 nuclease mapping of the 5' terminus of the in vitro transcripts. Transcription initiates at or near the in vivo initiation site of the heat shock protein gene and initiates at or near a site 14 nucleotides downstream of the in vivo start site of the 79B actin gene. The addition of the 79B actin, 88F actin, or heat shock protein templates to a HeLa extract transcription reaction precluded the transcription of a second template subsequently added. The exclusion occurs rapidly, within 15 s, is not dependent on transcription, and is only partially resistant to high concentrations of the second added template. We propose that stable protein-promoter complexes play an important role in maintaining exclusive transcription of the first template added in vitro.

Actins↗
PubMed1983

Two Drosophila actin genes in detail. Gene structure, protein structure and transcription during development.

DNA fragments representing the six Drosophila actin genes have been isolated by recombinant DNA techniques. We have compared the transcriptional characteristics of the actin genes at the cytological loci 79B and 88F. The activity of each gene in vivo was examined using gene-specific probes from transcribed, but non-translated 3' regions of each gene. The genes show similar patterns of transcriptional activity during development until the pupal stage, with two periods showing RNA accumulation at two to three hours and 12 to 15 hours during embryonic development, followed by large increases in the proportion of message from each gene in first and second instar larvae. During pupal development, the 88F gene apparently produces a larger proportion of transcripts than at any other developmental stage, while the transcripts of the 79B gene are reduced to a level lower than in first and second instar larvae. The 5' end of each messenger RNA in larvae has been mapped by nuclease S1 digestion of hybrids between restriction fragments of genes and homologous mRNAs. The two genes display widely differing capacities to serve as templates for transcription in vitro in HeLa cell extracts. The complete DNA sequences of both genes including the flanking regions immediately 3' and 5' to the gene are presented. These data permit comparison of the DNA sequences of these Drosophila actin genes with each other and with the DNA sequence and protein sequence information available for the actins of Drosophila and other organisms. These two genes share the common structural feature of an intervening sequence at amino acid 307, though the sequences within each intron differ greatly. This may be a reflection of a duplication event, followed by divergence of the intervening sequences. We discuss possible correlations between the DNA sequences of each 5' flanking region and the differences in transcriptional characteristics of these two distinct but closely related genes.

Actins↗
PubMed1982

Self-retaining ureteral stent catheters in the management of urologic complications of gynecologic malignancies.

Fifteen patients with ureteral obstruction secondary to advanced and/or recurrent gynecologic malignancies underwent endoscopic (3) or surgical transvesical (12) insertion of Gibbons (12) or Double "J" (3) stent catheters. Renal function improvement was noted in all but one patient who had renal parenchymal disease. No complication attributable to the insertion procedure was recorded. This approach to the treatment of ureteral occlusion in patients with gynecologic cancer is discussed and recommended.

Adult↗
PubMed1978

[Anastomosis between carotis externa and carotis interna circulation (indication and results) (author's transl)].

An extra-intracranial anastomosis operation was carried out in 60 stroke patients in order to bypass the occlusion or severe stenosis in the internal carotid or middle cerebral artery. Postoperative angiographical follow-up studies showed a well functioning extra-intracranial bypass in more than 90 % of the patients. In many cases repeat angiography done weeks or months following surgery revealed an enlargement of the caliber of the extracranial artery used for constructing the bypass and also of the cerebral arteries that were irrigated by the bypass. Furthermore we noted that the new collateral channel was able to fill a steadely increasing part of the cerebral circulation and that it was also found to irrigate territories of the brain that were previously well perfused by leptomeningeal anastomosis or retrograd flow through the ophthalmic artery etc. resulting in a reversal of the direction of blood flow in these collaterals. The neurological follow-up examinations revealed that the increase in cerebral blood supply following the extra-intracranial anastomosis operation resulted in a considerable improvement of the post-stroke neurological deficits.

Carotid Arteries↗