Biopsias percutáneas guiadas por escanografía: experiencia en el Hospital Universitario San Ignacio: período 2001- 2004 / Scanner-guided percutaneous biopsies: an experience at Hospital Universitario San Ignacio, 2001-2004

El término biopsia (gr. bios: vida, vital – opsis: ver) se refiere al acto de obtener una muestra de tejido vivo con el fin de establecer un diagnóstico preciso mediante su análisis histopatológico[1]. Las biopsias se pueden realizar a través de una cirugía (biopsia abierta) o por medio de la vía percutánea (biopsia cerrada). La primera biopsia percutánea trastorácica reportada data de 1883, se obtuvo para el diagnóstico de un proceso infeccioso y en 1886 para el diagnóstico de una enfermedad maligna, en ambos casos, el procedimiento se realizó sin ninguna guía o ayuda imagenológica[2]. En la actualidad es un procedimiento común en la determinación de la etiología de una anormalidad o alteración focal. Las biopsias percutáneas pueden ser realizadas bajo guía imagenológica, usando una variedad de métodos como la fluoroscopia, el ultrasonido, escanografía y menos frecuentemente la resonancia magnética.

Efficacy of ion-selective probes in early epicardial in vivo detection of myocardial ischemia.

Myocardial hypoxia is accompanied by increased epicardial potassium activity. In this experimental study in rabbits (n = 13), with ion-selective probes, we correlated our findings with an exact evaluation of myocardial oxygen tension, hemodynamic data and arterial and venous blood gas analysis. The epicardial potassium activity had good correlation with these parameters (pm = -0.95, pco = -0.93 and pa = -0.72, pv = -0.96, respectively). Therefore, the clinical use of these electrodes can be recommended for continuous monitoring in intensive care units.

[Detection of myocardial ischemia by epicardial detection of potassium ion activity]. / Myokardialer Ischämienachweis durch epikardiale Detektion von Kaliumionenaktivitäten.

Early detection of myocardial ischaemia is a central problem in cardiological and cardiosurgical intensive care. A new approach is the use of ion-selective electrodes implanted directly on the myocardium, enabling detection of increased potassium activity as an indication of general hypoxia. After a comprehensive study of the electrode parameters, an animal experiment was carried out, in which it was found that respiration-induced hypoxia resulted in an increase in epicardial potassium activity (p < 0.01). Blood gas analysis performed simultaneously revealed reduced arterial pO2, but no acidosis. Haemodynamic data evidenced hypoxic depression of circulatory parameters. Histological examinations of the myocardium beneath the electrodes revealed typical lymphocytic infiltration. Electron microscopy demonstrated crystolysis in the mitochondria as an early sign of hypoxia, thus confirming the sensitivity of these electrodes. This underscores the potential of ion-selective electrodes for the detection of myocardial ischaemia, and they should now be investigated in the clinical setting.

[Measuring stroke volume of the ascending aorta with an extravascular Doppler ultrasound probe in comparison with aortic thermodilution]. / Messung des Herzzeitvolumens an der Aorta ascendens mit extravaskulärer Doppler-Ultraschallsonde im Vergleich zur aortalen Thermodilution.

Currently, no reliable minimally invasive method of measuring cardiac output continuously in neonates and children undergoing cardiac surgery is available. An extravascular Doppler probe was used to measure cardiac output in 15 New Zealand White rabbits (average weight 3.5 kg, range 2.5-4.5 kg). The results obtained were compared with cardiac outputs determined using the aortic thermodilution principle. The mean cardiac outputs measured with the extravascular Doppler probe was 0.37 +/- 0.01 l/min as compared with 0.39 +/- 0.01 l/min with aortic thermodilution. Regression analysis revealed a close correlation (r = 0.973) between the two techniques. The extravascular Doppler techniques is an option for continuous and reliable cardiac output measurement in small animals used in surgical experiments (open chest models) and in neonates or children during surgical repair of complicated congenital heart conditions.

[Animal experiment study of the design of microelectrodes for selective detection of epicardial potassium ion activities]. / Tierexperimentelle Studie zum Aufbau von Mikroelektroden für den selektiven Nachweis von epikardialen Kaliumionenaktivitäten.

Early detection of myocardial ischaemia following cardiac surgery remains a central problem of intensive care medicine. On the basis of the observation in the epicardium that an elevated potassium activity accompanies myocardial ischaemia, a miniaturized electrode system for the measurement of epicardial potassium concentration was constructed and tested. Different types of electrode were implanted in two groups of rabbits. The electrode parameters were satisfactory (slope, screening) and it proved possible to record interference-free myocardial ion potentials, which with regard to the ionophores used is selective for potassium ion activity in the solid phase electrode. The system thus meets the prerequisites for further investigations into its suitability for early diagnosis of ischaemia.

[Basic therapy of chronic inflammatory joint diseases with D-penicillamine and disorders of wound healing in rheumatoid orthopedic interventions]. / Basistherapie der chronisch-entzündlichen Gelenkerkrankungen mit D-Penicillamin und Wundheilungsstörungen bei rheumaorthopädischen Eingriffen.

In the past, D-penicillamine has been thought to cause wound healing disturbances due to its influence on connective tissue. A series of 217 operations in 150 patients with rheumatoid arthritis on D-penicillamine treatment were performed and compared with controls (106 operations in 86 patients with rheumatoid arthritis). It was shown that disturbances of wound healing were less in patients on D-penicillamine therapy (12.4%) than in patients who did not receive D-penicillamine (18.9%). A perioperative withdrawal of D-penicillamine therefore does not seem justified.

Cytoplasmic membrane changes during adaptation of the fresh water cyanobacterium Synechococcus 6311 to salinity.

In this investigation, changes were characterized in cell structure and cytoplasmic membrane organization that occur when the freshwater cyanobacterium Synechococcus 6311 is transferred from 'low salt' (0.03 molar NaCl) to 'high salt' (0.5 molar NaCl) media (i.e. sea water concentration). Cells were examined at several time points after the imposition of the salt stress and compared to control cells, in thin sections and freeze fracture electron microscopy, and by flow cytometry. One minute after exposure to high salt, i.e. 'salt shock', virtually all intracellular granules disappeared, the density of the cytoplasm decreased, and the appearance of DNA material was changed. Glycogen and other granules, however, reappeared by 4 hours after salt exposure. The organization of the cytoplasmic membrane undergoes major reorganization following salt shock. Freeze-fracture electron microscopy showed that small intramembrane particles (diameter 7.5 and 8.5 nanometers) are reduced in number by two- to fivefold, whereas large particles, (diameters 14.5 and 17.5 nanometers) increase two- to fourfold in frequency, compared to control cells grown in low salt medium. The changes in particle size distribution suggest synthesis of new membrane proteins, in agreement with the known increases in respiration, cytochrome oxidase, and sodium proton exchange activity of the cytoplasmic membrane.

23Na and 31P NMR studies of the effects of salt stress on the freshwater cyanobacterium Synechococcus 6311.

We have used 23Na and 31P nuclear magnetic resonance (NMR) spectroscopy to elucidate some of the bioenergetic changes that occur in the freshwater cyanobacterium Synechococcus 6311 after a transition from growth medium (Na concentration 0.01 M) to medium containing 0.5 M NaCl. 23Na NMR analysis showed Na rapidly penetrates the cells under dark aerobic conditions; cells grown for several days in high salt medium, however, reestablish a low internal sodium content, comparable to control cells. For 31P NMR analysis, a system was devised to aerate and illuminate cell suspensions during spectral acquisition. The NMR spectra showed that when cells are presented with 0.5 M NaCl (final concentration), nucleotide triphosphate peaks decrease, the inorganic phosphate peak increases, and the cytoplasmic pH transiently increases from 7.4 to 7.9. Pyrophosphate added to cell suspensions is hydrolyzed to inorganic phosphate apparently by an extracellular phosphatase, allowing external and internal pools of inorganic phosphate to be distinguished. Nucleotide triphosphate levels fall almost as much when cells are incubated in darkness as under anoxia, indicating that both respiration and photosynthesis contribute to the maintenance of intracellular ATP levels. Cells grown in high salt medium for several generations exhibited a pattern of 31P metabolites similar to control cells, except that they produced more (and more intense) peaks in the monoester phosphate region, presumably signals from sugar phosphates.

Carbon-13 NMR studies of salt shock-induced carbohydrate turnover in the marine cyanobacterium Agmenellum quadruplicatum.

Carbon turnover in response to abrupt changes in salinity, including the mobilization of glycogen for use in osmoregulation was studied with pulse-chase strategies utilizing nuclear magnetic resonance (NMR)-silent and NMR-detectable 12C and 13C isotopes, respectively. Growth of Agmenellum quadruplicatum in 30%-enriched 13C bicarbonate provided sufficient NMR-detectability of intracellular organic osmoregulants for these studies. A comparison of NMR spectra of intact cells and their ethanol extracts showed that the intact cell data were suitable for quantitative work, and, when combined with ESR measurements of cell volumes, yielded intracellular glucosylglycerol concentrations without disrupting the cells. NMR pulse-chase experiments were used to show that 13C-enriched glycogen, which had previously been accumulated by the cells under nitrogen-limited growth at low salinities, could be utilized for the synthesis of glucosylglycerol when the cells were abruptly transferred to hypersaline media, but only in the light. It was also shown that the accumulation of glucosylglycerol in the light occurred on a time scale similar to that of cell doubling. Depletion of glucosylglycerol when cells abruptly transferred to lower salinities appeared to be rapid--the intracellular pool of this osmoregulant was decreased 2-fold within 2 hours of hypotonic shock.

[Intraoperative electroneurography during decompression of the median nerve in the carpal tunnel]. / Intraoperative Elektroneurographie bei Dekompression des N. medianus im Karpaltunnel.

Observations in 261 patients suffering from carpal tunnel syndrome in whom 303 decompressions of the median nerve had been performed led us to the conclusion that a definite improvement of the transmission rate occurs during operation. Distal latency has been measured during operation in 20 patients before and after transecting the flexor retinaculum, after neurolysis and also after releasing the tourniquet. Our findings confirm a positive effect on the transmission rate occurring immediately after transecting the flexor retinaculum.

The role of Na2S in anoxygenic photosynthesis and H2 production in the cyanobacterium Nostoc muscorum.

Na2S is known to support anoxygenic photosynthesis in some strains of cyanobacteria and to stimulate H2 production in N2 fixing filaments of Nostoc muscorum. We have shown electron transfer between Na2S and Photosystem I to be dependent on cytochrome b559 which was detected only in vegetative cells. An electron mediator was required to support Na2S driven nitrogenase activity in isolated heterocysts. Na2S was also found to deplete the ATP pool, probably by inhibiting electron transfer from Photosystem I.

[Meralgia paresthesia should also be considered in coxarthrosis]. / Bei Koxarthrose auch an die Meralgia paraesthetica denken!

Due to its variable attitude--and motiondepending pain symptoms meralgia paraesthetica may easily be misinterpreted as an affection of the hip joint or not be regarded as additional and sometimes chief complaint of that. Moreover our investigations show that meralgia paraesthetica is seen quite frequently in patients suffering from coxarthrosis. A case report illustrates the subject. Finally diagnostic and therapeutic proceedings are suggested.

Membrane-membrane and membrane-ligand interactions in Chlamydomonas mating.

Our investigations of the mating reaction of Chlamydomonas revealed a surprisingly intricate series of interrelated events. Adhering sites are moved to the flagellar tips in a fashion highly reminiscent of the capping of surface ligands over the centriolar regions of lymphocytes (28). Tipping is prevented by the gam-1 mutation and by agents that interact with tubulin; the molecular mechanism(s) for the inhibition effects are currently being sought. Tip locking appears to be accompanied by the accumulation of a dense material beneath the tip membrane, a postulated alteration of axonemal structure, and an immobilization of component(s) involved in surface motility. Two mating signals are then transduced to the locked-in cells who respond by shedding cell walls, activating mating structures, and fusing together. Signal transmission and/or reception is sensitive to such agents as trypsin, chymotrypsin, and cold temperature. Once zygotic cell fusion has occurred, tip unlocking and a reversal of the tip activation response appear to occur in parallel. Since all of these events can occur within 30 sec, the mating reaction serves as an experimental paradigm for studying rapid cellular responses to specific membrane-membrane interactions.