Biomedical subjects
Publications and source records attributed to J Sanchez.
The differential diagnosis of rectal pain is extensive, and etiologies range from common anorectal disorders to more complex pelvic floor dysfunctional syndromes. The authors present a case of a man with rectal pain secondary to a congenital pelvic arteriovenous malformation. These malformations are rare and, to the authors' knowledge, have not been reported in association with rectal pain.
A coupled assay has been worked out to study spinach (Spinacea oleracea L.) nitrate reductase under low, more physiological concentrations of NADH. In this assay the reduction of nitrate is coupled to the oxidation of malate catalyzed by spinach NAD-malate dehydrogenase. The use of this coupled system allows the assay of nitrate reductase activity at steady-state concentrations of NADH below micromolar. We have used this coupled assay to study the kinetic parameters of spinach nitrate reductase and to reinvestigate the putative regulatory role of adenine nucleotides, inorganic phosphate, amino acids, and calcium and calmodulin.
We describe a phase contrast microscopy method for direct observation of classical and El Tor vibrios to agarose beads containing covalently attached L-fucose or D-mannose. Binding of the vibrios to L-fucose beads was found to correlate with fucose-sensitive agglutination of human O erythrocytes, while binding of bacteria to beads with D-mannose was consistent with mannose-sensitive agglutination of chicken erythrocytes. Furthermore, vibrios expressing both fucose and mannose-sensitive hemagglutinins adhered equally to L-fucose and D-mannose-containing beads. Because this procedure is neither subject to biological variations in different populations of erythrocytes nor affected by other factors known to interfere with hemagglutination tests, it offers a suitable, more robust and specific alternative to detect functional adhesins in Vibrio cholerae and other bacteria.
A recombinant gene fusion protein composed of an Escherichia coli heat-stable enterotoxin (STa) peptide epitope fused to the amino end of the cholera toxin B subunit was used to detect STa produced by clinical isolates of enterotoxigenic E. coli (STa-ETEC) by a single monoclonal antibody-based inhibition GM1 enzyme-linked immunosorbent assay. In this test, 100% sensitivity and 100% specificity were observed for use of the recombinant protein in either its purified form or as crude Vibrio cholerae culture supernatants in detection of STa-ETEC.
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The present study examined the effect of structural analogs of clonidine on feeding in both rabbits and monkeys. In rabbits, lofexidine and tizanidine either did not influence or decreased food intake in contrast to clonidine, which stimulated food intake. Lofexidine elicited easily observed decreases in motor behavior with several of the doses used in the study. Changes in motor behavior induced by tizanidine were more subtle. Conversely, lofexidine and tizanidine significantly increased feeding behavior in Stumptail macaque monkeys, as did clonidine. The results suggest that, in contrast to rabbits, Stumptail monkeys are more useful in searching for an 'orectic' effect of clonidine analogs.
An approach to the construction of amperometric biosensors based on the incorporation of an enzyme in silicone grease and using the grease to fill micropores on a graphite surface is described. The enzyme-grease electrode concept, illustrated with the enzyme tyrosinase, offers a very simple, rapid and inexpensive approach to the fabrication of enzyme electrodes. The tyrosinase electrode responds very rapidly to dynamic changes in the concentration of phenolic compounds. A response time (t95%) as low as 5 s has been determined. With flow injection, 120 samples per hour can be processed with a relative standard deviation of 2.4%. The electrode remains active for about 12 d. The detection limit for dopamine is 6 x 10(-6) M. This method of biosensor construction should be applicable to other enzyme-substrate systems.
We have constructed an overexpression system in which the gene encoding the B subunit of cholera toxin (CTB) was placed under the control of the strong tacP promoter in a wide host range plasmid. Recombinant nontoxigenic classical and E1 Tor Vibrio cholerae strains of different serotypes harboring this plasmid excreted 10- to 100-fold higher amounts of CTB than any other wild-type or recombinant strain tested and may therefore be useful killed oral vaccine strains. The manipulations to place the CTB gene under tacP also included, by design, the introduction of single enzyme restriction sites for gene fusions to the CTB amino terminus. Cloning into these sites allows construction of CTB-derived hybrid proteins carrying various putative vaccine peptide antigens.
Buttercup extract (BE), an extract of the buttercup plant (Zanthoriza simplicissima), inhibits RNA and DNA synthesis by HL-60 promyelocytic leukemia cells. Exposure of these cells to 3% BE for 48 hours results in dramatic inhibition of RNA synthesis without loss of cell viability. The effect of BE is partially reversible over 12-24 hours with the level of RNA synthesis returning nearly to control levels during this time period. DNA synthesis is also reversibly inhibited by exposure to BE. Despite the inhibition of RNA synthesis in HL-60 cells, there is no decrease in the level of c-myc mRNA, even at high BE concentrations. The level of gene-specific mRNA for the c-Ha-ras, c-fms, and c-mos genes in these cells also remained constant during exposure to BE. Ribosomal RNA is not degraded during 24 hours of BE treatment in vitro, suggesting that BE does not maintain the relative mRNA level for these genes by selective degradation of other RNA species. The inhibition of RNA and DNA synthesis by BE without a corresponding alteration in the level of expression of the c-myc gene suggests that this agent dissociates c-myc expression and cellular proliferation in these cells.
The expression of two cell-bound haemagglutinins, one sensitive to L-fucose (FSHA) and the other to D-mannose (MSHA), on Vibrio cholerae O1 strains of both the classical and the El Tor biotypes was studied by (i) agglutination of chicken and human group O erythrocytes in the presence of L-fucose or D-mannose, (ii) binding of the bacteria to L-fucose- and D-mannose-coated agarose beads, and (iii) agglutination of the bacteria by 'biotype-specific' antisera. All of the 12 classical strains studied that were isolated before 1979 gave FSHA of human O erythrocytes whereas only 6 of 17 classical strains isolated during recent epidemics expressed FSHA; a few of the classical strains expressed MSHA in addition to FSHA. All the El Tor strains gave MSHA of chicken erythrocytes and one strain also expressed FSHA. Both the cell-bound HAs were optimally expressed during the exponential phase of growth; FSHA markedly decreased during the late exponential phase while the MSHA usually persisted into the stationary phase. The expression of FSHA and MSHA correlated very well with the direct binding of vibrios to fucose- and mannose-coated agarose beads, respectively. Antiserum 'specific' for classical vibrios agglutinated classical strains expressing FSHA and also the El Tor strain exhibiting FSHA. Similarly, the anti-El Tor serum agglutinated all El Tor strains and also classical strains expressing MSHA, suggesting that the 'biotype-specific' sera were specific for the biotype-associated cell-bound HAs.
Staining and histochemical methods, immunocytochemical and electron microscopy were used to individualize the somatotropic or GH cells in the adenohypophyseal pars distalis of the kid. They are found in a sagittal section throughout the pars distalis constituting 34% of the hypophyseal cell population. They are 12.37 micron in size and have as an ultrastructural characteristic secretory spherical granules of a large size (males, 391 nm and females, 427 nm) which are very electrodense.
The OmpC outer membrane protein of Escherichia coli was used as a carrier molecule for the nonimmunogenic heat-stable enterotoxin STa. Two fragments of different lengths of the gene encoding STa were fused in vitro to the 3' terminus of the truncated ompC gene. The resulting OmpC-STa hybrid proteins could be detected by L-[35S]cysteine labeling, and they were processed and thus exported. All synthesized hybrid protein remained cell bound and was found by fractionation mainly in the periplasm. Immunoblot analysis showed that the hybrid proteins reacted in vitro both with anti-OmpC and anti-STa antibodies, and immunization of rabbits evoked an antibody response to either of these proteins.
In this report, we describe five cases of dermatophytosis caused by dysgonic strains of Microsporum canis which occurred in the area of Bilbao (Spain). The clinical presentations and responses to treatment of these infections were apparently similar to those caused by typical strains of this species but the increasing prevalence of dysgonic and other atypical strains of M. canis and the relative stability of the dysgonic morphology are the important features shown in our study. Contact with animals was confirmed by all of the patients, but in only one case was this possible infectious origin demonstrated mycologically. One of the patients, a heroin abuser with AIDS, showed a simultaneous infection with Trichophyton mentagrophytes var. mentagrophytes.
The authors compared pupil responsiveness to light, convergence, and the effects of topical cocaine 4%, epinephrine 1%, phenylephrine 1%, homatropine 10%, and pilocarpine 1% in a group of 62 diabetics with a sex- and age-matched group of normal subjects. The duration of disease, metabolic control, and type of diabetes mellitus, the presence and severity of diabetic retinopathy, and evidence of systemic vegetative neuropathy were considered. It was found that sympathetic denervation was related significantly to the duration of disease and to the development of systemic autonomic neuropathy. There were also signs of iris myopathy in the pupil alterations of long-standing diabetics, explaining the poor pupil responsiveness to mydriatics occasionally found in these patients. Pupillary autonomic diabetic neuropathy should be considered an early and major sign of the development of systemic vegetative diabetic disease.
In order to investigate the prognostic value of immunologic markers together with the most relevant clinical and hematological disease characteristics in acute myeloblastic leukemia (AML), the reactivity of blast cells from 102 patients with AML was analyzed with a panel of twenty monoclonal antibodies. The univariate analysis showed that five parameters had an adverse effect on both complete remission (CR) and survival: advanced age (greater than 60 years), anemia (hemoglobin concentration (Hb) less than 10g/dl), the expression of the antigens detected by the anti-megakaryocytic antibodies (CDw41/CDw42), the monocytic antibodies (CD14), and the CD9 (FMC56, FMC8) antigen. In addition, the failure to obtain CR had a significant adverse effect on survival (p less than 0.0001). Multivariate analysis showed that only age and Hb had a significant influence on CR while for predicting survival the most important independent prognostic factors were: CR, age, number of platelets and reactivity with the CD9 antibody. These results show that immunological markers could represent a valuable tool in the assignment of risk categories in AML patients.