Voltage-dependent potassium currents in hypertrophied rat astrocytes after a cortical stab wound

Changes in the membrane properties of reactive astrocytes in gliotic cortex induced by a stab wound were studied in brain slices of 21-28-day-old rats, using the patch-clamp technique and were correlated with changes in resting extracellular K+ concentration ([K+]e) measured in vivo using K+-selective microelectrodes. Based on K+ current expression, three types of astrocytes were identified in gliotic cortex: A1 astrocytes expressing a time- and voltage-independent K+ current component and additional inwardly rectifying K+ currents (K(IR)); A2 astrocytes expressing a time- and voltage-independent K+ current component and additional delayed outwardly rectifying K+ currents (K(DR)); and complex astrocytes expressing K(DR), K(IR), and A-type K+ (K(A)) currents and Na+ currents (I(Na)). Nestin/bromodeoxyuridine (BrdU)-negative A1 astrocytes were found further than approximately 100 microm from the stab wound and showed an upregulation of K(IR) currents within the first day post-injury (PI), correlating with an increased resting [K+]e. Their number declined from 62% of total astrocytes in control rats to 41% in rats at 7 days PI. Nestin/BrdU-positive A2 astrocytes were found only within a distance of approximately 100 microm from the stab wound and, in comparison to those in control rats, showed an upregulation of K(DR) currents. Their number increased from 8% of the total number of astrocytes in control rats to 39% 7 days PI. Both A1 and A2 astrocytes showed hypertrophied processes and increased GFAP staining, but an examination of cell morphology revealed greater changes in the surface/volume ratio in A2 astrocytes than in A1 astrocytes. Complex astrocytes did not display a hypertophied morphology; K(IR) currents in these cells were upregulated within 1 day PI, while the K(DR), K(A), and I(Na) currents were increased only 6 h PI. We conclude that two electrophysiologically, immunohistochemically, and morphologically distinct types of hypertrophied astrocytes are present at the site of a stab wound, depending on the distance from the lesion, and may have different functions in ionic homeostasis and/or regeneration.     

Ecological conditions of natural foci of tularaemia in the Czech Republic

Tularaemia, a zoonosis of veterinary and public health importance, commonly occurs in the Czech Republic as well as other countries of Northern Hemisphere. The objective of this study was to analyse the environmental conditions of distribution of natural foci of tularaemia and their long-term persistence in the Czech Republic. A geographic information system has been used for this purpose. A new variable (x _t), the mean number of natural foci in a specific area, has been suggested for the evaluation of diseases occurring in natural foci. Comparing two 15-year periods, a close correlation between the geographic distribution and numbers of natural foci of tularaemia in the Czech Republic in 1971–1985 and 1986–2000 (r = 0.91, n = 1814, t = 92.50, p = 0.01) was found. Natural foci of tularaemia have been persistent, but not stationary, over the period of 30 years and the geographic area of their occurrence has not been considerably growing or diminishing in the Czech Republic. The highest numbers of natural foci of tularaemia were in habitats of alluvial forests (x _t = 7.20), geographic areas of up to 200 m of elevation above sea (x _t = 9.18), 8.1–10.0 °C of mean annual air temperature (x _t = 6.24), 450–700 mm of mean annual precipitation (x _t = 2.84), and 2001–2200 hour of mean annual sunshine duration (x _t = 8.77). It was proved that tularaemia persists in specific areas of natural foci, the general environmental conditions of which can be defined and make it possible to predict the occurrence of tularaemia in other areas of suitable conditions.     

Beta-cytotrophic action of glibenclamide on the pancreas of diabetic patients

Summary Observations on the beta-cytotrophic action of glibenclamide are reported in three cases of maturity-onset diabetes treated with insulin and glibenclamide and in whom autopsy was carried out after death due to causes other than diabetes. Since histological examination revealed the presence of large numbers of giant islets, of islets with irregular and not clearly defined outlines, the unusual shape and arrangement of individual cells within the islets and the presence of -granules in the newly formed islets, it is thought that these were signs of the regeneration of pancreatic islets. The possibility is discussed that these newly formed islets originate both from the exocrine pancreatic tissue and from the epithelium of secondary pancreatic ducts.

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Zusammenfassung Es werden Beobachtungen über den beta-zytotropen Effekt von Glibenclamid bei drei Fällen von mit Insulin und Glibenclamid behandeltem Erwachsenen-Diabetes beschrieben, bei welchen nach dem Tod infolge nichtdiabetischer Ursache eine Obduktion vorgenommen wurde. Da die histologische Untersuchung eine grosse Anzahl von Rieseninseln, Inseln mit unregelmässigen und nicht klar erkennbaren Grenzen, mit einzelnen Zellen von ungewöhnlicher Form und Anordnung innerhalb der Inseln und mit beta-Granulation in den neugeformten Inseln zeigte, wird angenommen, dass es sich um Zeichen der Regeneration pankreatischer Inseln handelt. Es wird die Möglichkeit diskutiert, dass diese neugeformten Inseln sowohl aus dem exokrinen Pankreasgewebe als auch aus dem Epithel der sekundären Pankreasgänge hervorgehen.

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Resumen Se exponen algunas observaciones sobre la acción betacitotrófica de la glibenclamida, referente a tres casos de diabetes en edad madura tratados con sulfanilurea y con insulina, los cuales fueron sometidos a comprobación autópsica tras defunción debida a causas ajenas. Puesto que el examen histológico puso en evidencia la presencia de un gran número de islas gigantes, de islas con contornos irregulares y no claramente definidos, con forma y disposición infrecuente de las diversas células en el inerior de las islas, de gránulos en esas islas neoformadas, se opina que dichos indicios sean la expresión de la regeneración de las islas pancreáticas. Se aduce le posibilidad de que esas islas neoformadas tengan origen tanto en el tejido pancrático exócrino como en el epitelio de los dúctulos pancreáticos secundarios.

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Résumé On fait quelques observations sur l'action bêta-cytotrophique de la glibenclamide concernant trois cas de diabète de l'âge mûr traités avec sulfanilurée et insuline et pour lesquels on a effectué un examen nécroscopique après le décès provoqué par d'autres causes. L'examen histologique ayant mis en évidence la présence d'un grand nombre d'îlots géants, d'îlots avec des contours irréguliers et pas clairement définis, d'une forme et arrangement insolites des différentes céllules à l'intérieur des îlots, de granules dans ces îlots de formation toute récente, on a cru que ces signes étaient le résultat d'une régénération des îlots pancréatiques. On a également discuté la possibilité que ces îlots de formation récente originent du tissu pancréatique exocrine aussi bien que de l'épithélium des canaux pancréatiques secondaires.

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Riassunto Vengono riferite alcune osservazioni sull'azione beta-citotrofica della glibenclamide, riguardanti tre casi di diabete dell'età matura trattati con la sulfanilurea e con l'insulina e nei quali venne eseguito, dopo il decesso intervenuto per altre cause, riscontro autoptico. Poiché l'esame istologico ha evidenziato la presenza di un gran numero di isole giganti, di isole con contorni irregolari e non chiaramente definiti, di forma e disposizione non usuali delle singole cellule all'interno delle isole, di granuli in queste isole neoformate, si è pensato che tali segni siano espressione di rigenerazione delle isole pancreatiche. Viene discussa la possibilità che queste isole neoformate si originino sia dal tessuto pancreatico esocrino che dall'epitelio dei dotti pancreatici secondarî.

     

Glycoforms of CA125 antigen as a possible cancer marker

CA125, a coelomic epithelium-related antigen, is expressed in both normal and pathological conditions. In this study, we compared the glycosylation of CA125 antigen from amniotic fluid and the ovarian carcinoma cell line OVCAR-3, in order to detect possible differences as a specific marker of their origin. Antigens from both sources were radiolabelled and subsequently subjected to the affinity chromatography, using plant lectins differing in carbohydrate specificity as ligands. A common chromatographic scheme was applied to all columns, i.e. they were eluted with: a) washing buffer to wash out non-bound and low-affinity bound fractions, b) a solution of inhibitory sugar and c) a low pH buffer, to release the high affinity bound fractions. CA125 antigen from each source was found to be heterogeneous in respect to the existence of multiple glycoforms, with O-linked glycan chains predominating. However, the binding patterns of both N- and O-linked glycan-reactive lectins indicated distinct differences in carbohydrate composition between CA125 antigen isolated from amniotic fluid and OVCAR-3 cell line. The observed specificites of CA125-oligosaccharide chains might be of special importance from the biomedical aspect, in terms of their possible use for clinical evaluation of gynecological functions in health and disease.     

Transplacental Transmission of Cutaneous Leishmania mexicana Strain in BALB/c Mice

The vertical transmission of leishmaniasis has been reported in species that cause visceral leishmaniasis. However, this condition has scarcely been documented in species that cause cutaneous leishmaniasis. The aim of this study was to determine experimentally whether L. mexicana is transmitted vertically. A control group of BALB/c mice and a group infected with L. mexicana were mated, the gestation was monitored, and females were killed before delivery. Four resorptions (P = 0.023) and eight fetal deaths (P = 0.010) were observed in the infected female group; furthermore, the offspring body weight of the infected group was lower than the body weight of the healthy group (P = 0.009). DNA amplification by polymerase chain reaction (PCR) revealed that all placentas and maternal spleens as well as 39 of 110 fetal spleens obtained from the offspring of infected mothers tested positive for Leishmania. In conclusion, L. mexicana is transmitted transplacentally and causes fetal death, resorption, and reduction in offspring body weight.