RESUMEN
Gallbladder Na(+) absorption is linked to gallstone formation in prairie dogs. We previously reported Na(+)/H(+) exchanger (NHE1-3) expression in native gallbladder tissues. Here we report the functional characterization of NHE1, NHE2 and NHE3 in primary cultures of prairie dog gallbladder epithelial cells (GBECs). Immunohistochemical studies showed that GBECs grown to confluency are homogeneous epithelial cells of gastrointestinal origin. Electron microscopic analysis of GBECs demonstrated that the cells form polarized monolayers characterized by tight junctions and apical microvilli. GBECs grown on Snapwells exhibited polarity and developed transepithelial short-circuit current, I(sc), (11.6 +/- 0.5 microA. cm(-2)), potential differences, V(t) (2.1 +/- 0.2 mV), and resistance, R(t) (169 +/- 12 omega. cm(2)). NHE activity in GBECs assessed by measuring dimethylamiloride-inhibitable (22)Na(+) uptake under a H(+) gradient was the same whether grown on permeable Snapwells or plastic wells. The basal rate of (22)Na(+) uptake was 21.4 +/- 1.3 nmol x mg prot(-1) x min(-1), of which 9.5 +/- 0.7 (approximately 45%) was mediated through apically-restricted NHE. Selective inhibition with HOE-694 revealed that NHE1, NHE2 and NHE3 accounted for approximately 6%, approximately 66% and approximately 28% of GBECs' total NHE activity, respectively. GBECs exhibited saturable NHE kinetics ( V(max) 9.2 +/- 0.3 nmol x mg prot(-1) x min(-1); K(m) 11.4 +/- 1.4 m M Na(+)). Expression of NHE1, NHE2 and NHE3 mRNAs was confirmed by RT-PCR analysis. These results demonstrate that the primary cultures of GBECs exhibit Na(+) transport characteristics similar to native gallbladder tissues, suggesting that these cells can be used as a tool for studying the mechanisms of gallbladder ion transport both under physiologic conditions and during gallstone formation.
Asunto(s)
Células Epiteliales/metabolismo , Vesícula Biliar/metabolismo , Intercambiadores de Sodio-Hidrógeno/metabolismo , Animales , Transporte Biológico Activo/fisiología , Células Cultivadas , Electrofisiología , Células Epiteliales/ultraestructura , Vesícula Biliar/patología , Cálculos Biliares/metabolismo , Cálculos Biliares/patología , Expresión Génica/genética , Hidrógeno/metabolismo , Concentración de Iones de Hidrógeno , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sciuridae , Sodio/metabolismo , Intercambiadores de Sodio-Hidrógeno/genéticaRESUMEN
The purpose of this study was to evaluate the effects of various laser wavelengths on human meniscal tissue in vitro and to compare them with the effects of electrosurgical devices. The carbon dioxide (CO2) laser produced the best cutting and ablating effects among the infrared lasers, although the contact neodymium:yttrium-aluminum-garnet (Nd:YAG) and holmium:YAG (Ho:YAG)lasers were nearly as satisfactory, offering the additional advantage of fiberoptic capability and the ability to be used in saline. The free-beam Nd:YAG laser and coagulation mode electrosurgical device produced unacceptably severe thermal changes. The excimer laser at 308 nm produced the best tissue effect and caused no detectable adjacent thermal change in the tissue.
Asunto(s)
Electrocirugia , Terapia por Láser , Meniscos Tibiales/cirugía , Electrocirugia/efectos adversos , Electrocirugia/instrumentación , Electrocirugia/métodos , Estudios de Evaluación como Asunto , Humanos , Terapia por Láser/efectos adversos , Terapia por Láser/instrumentación , Terapia por Láser/métodos , Meniscos Tibiales/ultraestructuraRESUMEN
The role of collagen in microvascular growth was investigated using the aortic ring model of angiogenesis. Collagen production by vasoformative outgrowths in plasma clot culture of rat aorta was either stimulated with ascorbic acid or inhibited with the proline analogue cis-hydroxyproline. Microvessels proliferating in the absence of ascorbic acid supplements became ecstatic and developed large lumina. In contrast, newly formed microvessels in the presence of ascorbic acid remained small and maintained thin lumina throughout the angiogenic process. Biochemical studies demonstrated enhanced collagen production and deposition in cultures treated with ascorbic acid. Ultrastructural studies of these cultures showed a marked increase in newly formed interstitial collagen in the perivascular matrix and in regions of the plasma clot containing nonendothelial mesenchymal cells. Small microvessels with thin lumina similar to the ones observed in ascorbic acid-treated plasma clot cultures were obtained by growing aortic explants in gels of interstitial collagen in the absence of ascorbic acid. Inhibition of collagen production with the proline analogue cis-hydroxyproline had a marked anti-angiogenic effect in both plasma clot and collagen gel cultures. The anti-angiogenic effect of cis-hydroxyproline was abolished by adding L-proline to the culture medium, thereby restoring normal metabolism. These results support the hypothesis that angiogenesis is regulated by collagen production and suggest that the size of newly formed microvessels is influenced by the degree of collagenization of the extracellular matrix.
Asunto(s)
Colágeno/metabolismo , Neovascularización Patológica/fisiopatología , Animales , Aorta/citología , Aorta/fisiología , Aorta/ultraestructura , Ácido Ascórbico/farmacología , Vasos Sanguíneos/efectos de los fármacos , Vasos Sanguíneos/fisiología , Vasos Sanguíneos/ultraestructura , División Celular/efectos de los fármacos , División Celular/fisiología , Células Cultivadas , Colágeno/fisiología , Matriz Extracelular/metabolismo , Hidroxiprolina/farmacología , Masculino , Microscopía Electrónica , Ratas , Ratas Endogámicas F344RESUMEN
Fifty-three organ, cellular and activity indices were assessed in aging mice of 8 strains and hybrids (5 inbred strains, 1 random bred strain and 2 hybrids of inbred strains) in an attempt to determine which aspects of immunologic aging are characteristic of the species. The results indicate that thymic weight, cellular, and activity indices exhibit a statistically significant negative correlation with age for mice of all 8 strains and hybrids; and B cell cellular indices show a statistically significant positive correlation with age for all mice, while the B cell activity index, lipopolysaccharide response, is dependent on the strain or hybrid. This correlation study supports the view that the T cell component of the immune system deteriorates with age while the B cell component remains relatively intact. Further, the results suggest that thymic aging is a characteristic of the mouse species and that the intrinsic "clock" for immunologic aging resides in the thymus, because most splenic and lymph node T cell activity and cellular indices are associated with thymic weight and cellular indices. Finally, the findings that indices which correlate best with age show the same trend for all strains and hybrids examined suggest that (a) if randomly occurring somatic mutation does play a role in immunologic aging, its influence is limited, and (b) genetic factors not easily influenced by environmental factors regulate immunologic aging.
Asunto(s)
Envejecimiento , Ratones Endogámicos/inmunología , Animales , Peso Corporal , Inmunidad Celular , Lipopolisacáridos/inmunología , Ganglios Linfáticos/inmunología , Ratones , Ratones Endogámicos/crecimiento & desarrollo , Fitohemaglutininas/inmunología , Bazo/inmunología , Linfocitos T/inmunologíaRESUMEN
A mutation at the divD locus in Salmonella typhimurium confers a round-cell morphology and enhances cell division under certain growth conditions.