Biomedical subjects
Publications and source records attributed to M García.
Colonies of Streptomyces antibioticus were studied by transmission and scanning electron microscopy. The micrographs show that substrate mycelium growth takes place among an intercellular material and this mycelium is covered by a surface film. This structure could be a boundary between the aerial mycelium and the substrate mycelium.
Human umbilical vein endothelial cells (HUVEC) were treated with recombinant interleukin (IL)-1 beta, and the metabolism of exogenous linoleic acid was studied. High performance liquid chromatography, gas chromatography-mass spectrometry, and chiral analysis revealed that HUVEC enzymatically convert linoleic acid mainly into 13-(S)hydroxy-9(Z),11(E)-octadecadienoic (13-HODE) and 9-(R)hydroxy-10(E),12(Z)-octadecadienoic acids, which may isomerize toward all-trans compounds. IL-1 beta increased the formation of all octadecanoids in a time- and dose-dependent manner with similar EC50 (approximately 1 unit/ml). The apparent Km values of linoleic acid were 15.59 +/- 8.39 and 152.9 +/- 84 microM (p < 0.05) in IL-1 beta-treated cells and controls, respectively, indicating a higher substrate affinity in cells stimulated with IL-1 beta. Ratios of S/R enantiomers for the hydroxyoctadecanoids produced by untreated and IL-1 beta-treated cells were similar to those from isolated cyclooxygenases (COXs), whereas isolated 15-lipoxygenase yielded 13-HODE with a strict S configuration. The formation of octadecanoids was inhibited in a dose-dependent manner by several COX inhibitors in both controls and IL-1 beta-treated cells, COX2 selective inhibitors being more effective on IL-1 beta-treated cells than on controls. COX1 and COX2 protein levels increased less than 2-fold and 8-fold, respectively, after IL-1 beta treatment. The specificity of COX inhibitors was proven since they did not inhibit 13-HODE formation by human polymorphonuclear leukocytes. Overall, these results indicate that COXs are responsible for the oxidative metabolism of linoleic acid in HUVEC, and IL-1 beta increases it by inducing the expression of new enzyme, mainly COX2.
OBJECTIVE: To determine the long term cardiovascular effects in adolescents exposed to ritodrine during prenatal stage. STUDY DESIGN: Twenty-seven ritodrine-exposed subjects and 19 controls, of both sexes, clinically healthy, and born at normal term, were evaluated for systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) each during 48 hours, with a Colin Ambulatory monitor. Data analysis were performed by individual Cosinor method, and non-parametric Mann Whitney's test and Lamotte procedures. RESULTS: Adolescents who were exposed to ritodrine showed losses in the HR rhythm and rising middle pulse values. Although SBP and DBP rhythm remains constant, the increase of maximum and minimum values for SBP as well as a rise of maximal rates of DBP suggest a possible hypertensive effect mediated by beta mimetic exposure. CONCLUSION: This study suggests a hypertensive effect mediated by beta mimetic exposure.
In this paper we have applied the matrix method to calculating spectacle magnification (SM) and relative spectacle magnification (RSM) for myopic eyes corrected with ophthalmic lenses (OLs). We have been able to obtain very simple expressions of the magnifications and analogous values to the ones obtained using other geometric methods. Through the paraxial 2 x 2 object-image matrix for spherical systems, we can calculate the correcting lens pupil matrix (ML) and the corrected ametropic eye pupil matrix (Mca). These two matrices, that is ML and Mca, directly provide the lateral magnification and the lens-eye system's image focal parameters that enable us to easily calculate SM and RSM. The magnifications have been calculated for the case of myopic eyes corrected with OLs, which shows the validity of this method since its results are similar to the ones obtained using other methods. The analysis of other correcting systems such as contact intraocular lenses will be presented in two associated papers (to be published as parts II and III of this review).
The in vitro expression of surface epitopes for different strains of Mycoplasma gallisepticum (MG) was studied with a panel of monoclonal antibodies (mAbs) using indirect colony immunostaining and Western blot (WB) analyses. Immunostaining of colonies with mAbs showed that five epitopes had different degrees of variable expression, while one epitope was permanently expressed in vitro. Colonies that failed to express the studied epitopes had the potential of phenotypically switching the expression of these epitopes in vitro. Variable and permanently expressed epitopes were associated with more than one protein and not all mAb-defined proteins were responsible for the immunostaining of intact MG colonies. The ability of MG to variably express their surface epitopes maybe the mechanism utilized by the microorganism to avoid the host immune response.
The earth of ornamental plants is one of the main reservoirs of Aspergillus type of fungi in hospital areas. We studied 174 ornamental interior plants from a hospital at Santiago. Samples were obtained from the soil surface and sowed in Sabouraud-glucose agar, adding streptomycin and G-penicillin. After 72 h of culture, at least one strain of Aspergillus was isolated from 140 samples (80.5%). The most frequently isolated strain was A fumigatus (129 samples), followed by A niger (75 samples). A fumigatus and A niger were the only isolated strains in 65 and 11 samples respectively. These findings confirm that ornamental plants can be important reservoirs of Aspergillus strains, a potential infectious agent for immunocompromised patients, in hospital areas.
BACKGROUND: A comparison of polymerase chain reaction (PCR) with methenamine silver stain was performed on clinical specimens for diagnosis of Pneumocystis carinii pneumonia in immunosuppressed patients. METHODS: 25 clinical samples (10 induced sputa, 12 transthoracic needle aspirations and 2 bronchoalveolar lavages) from 17 patients with AIDS and respiratory symptoms were studied. We performed DNA amplification by using 2 primers that amplify the mitochondrial large rDNA sequence of P. carinii. RESULTS: The sensitivity and specificity of the PCR technique were 92.8% and 100% respectively, with a positive predictive value of 100% and negative predictive value of 92.3%. The sensitivity of the silver stain were 65%, specificity 100%, positive predictive value 100% and negative predictive value 63%. CONCLUSION: The PCR technique is more sensitive than the methenamine silver stain for detecting Pneumocystis carinii in respiratory specimens from patients with pneumonia. Consequently it could be a very good alternative to classical methods in diagnosis of P. carinii infections.
We have studied the effect of carbamoylcholine in Trypanosoma cruzi epimastigote forms prelabelled with [32P]-Pi. Suspensions of cells were incubated at 28 degrees C to measure changes in the levels of [32P]-labelled phospholipids after stimulation. The presence of this cholinergic agonist induced changes in the phosphoinositide metabolism; a shift in the levels of phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 4-phosphate (PIP) and phosphatidic acid (PA) was observed, whereas the levels of the other glycerophospholipids were not changed. This study shows that carbamoylcholine either directly or indirectly influences changes in phosphoinositide metabolism.
A global kinetic analysis is presented of a model of an enzyme autocatalytic process, to which a reaction is coupled, in which the enzyme acts upon one of its substrates. The kinetic equations of both the transient phase and the steady state are derived for this mechanism. In addition, we determine the corresponding kinetic equations for several particular cases which are characterized by certain relations between the rate constants. Finally, a kinetic data analysis is proposed for one of these particular cases. It can easily be extended to any of the other cases.
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An ethnobotanical field study carried out in 200 rural communities determined that the leaves of Solanum chrysotrichum Schldl. are used in Mexican traditional medicine for the treatment of skin mycosis, being particularly recommended to cure Tinae pedis. Clinical trials were performed using a cream containing 5% of a methanolic leaf extract of this plant. Results showed that 45% of the patients were completely cured after 4 weeks of topical treatment. The rest of the cases improved notably in comparison with the control group of patients using the habitual miconazole treatment. The same plant extract inhibited the growth in vitro of the dermatophytes Trychophyton mentagrophytes, T. rubrum and Microsporum gypseum at MICs under 15 mg/ml.
The neurotoxic agent lindane was tested for its ability to alter the rate of ultrasonic isolation calls of suckling rats. Doses that did not produce any sign of convulsant activity significantly increased the number of calls and the cumulative time of calling in male pups. At days 10-13 of age after a single dose of 20 mg/kg lindane, animals showed more than twice the control call values. After daily dosing with 10 mg/kg during the first week of age call increases also appeared. It is suggested that lindane has an anxiogenic effect mediated through its action on the benzodiazepine-GABAA receptor-chloride channel complex.
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Endoscopic sphincterotomy is widely accepted as the technique of choice in the treatment of residual or recidivant choledocholithiasis since the results obtained with this technique are favorable when compared to biliary surgery in most series. However, the experience of long term follow up of patients with choledocholithiasis in whom this technique would have been applied as the only treatment is still scarce up to date. We have studied 40 patients (mean age 65.6 +/- 11.1 years) with residual or recidivant choledocholithiasis who had undergone endoscopic treatment successfully before the 30th of June 1985, who could be contacted by a mailed questionnaire or by phone by August 1990. The follow up time 70.7 +/- 19.4 months (mean +/- typical deviation). Out of them, 36 (90%) had been asymptomatic up to the contact date (30 cases) or up to death due to causes not related to biliary pathology (6 patients). Out of the 4 remaining patients, 2 presented mild dyspepsia and another patient has probably developed recidivant choledocholithiasis (according to I.V. cholangiography). The fourth patient presented a severe episode of cholangitis and acute pancreatitis, related to a new episode of choledocholithiasis and died 5 and a half years after the endoscopic sphincterectomy. This represents a 2.5% mortality. These long term results of endoscopic sphincterotomy in patients with residual or recidivant choledocholithiasis are an other point in favour of using this technique as the single treatment of choice in patients above 60 years old.
We communicate a case with the Carney triad (gastric leiomyosarcoma, pulmonary chondromatosis and extra-adrenal paraganglioma). It is, to our knowledge, the first case to be communicated in the Spanish scientific literature. We discuss some peculiar aspects of the debut and clinical evolution of this syndrome, together with its prognosis. We conclude that in clinical practice, the appearance in a young subject, specifically females, of multiple gastric myogenic tumors, should elicit the performance of further noninvasive procedures, needed to discard the diagnosis of the Carney triad.
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This paper presents an extension of the program developed by Varón, Havsteen, García, García-Cánovas & Tudela [(1990) Biochem. J. 270, 825-828] for the expression of the transient-phase and steady-state kinetic equations of a general enzyme system in which the only enzyme species present at the onset of the reaction is the free enzyme. The program has been extended to situations in which more than one enzyme species may be present at the onset of the reaction. The program is given in Supplementary Publication SUP50165 (5 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1991) 273, 5.