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1.
H. F. de Webster L. Lamperth J. T. Favilla G. Lemke D. Tesin L. Manuelidis 《Histochemistry and cell biology》1987,86(5):441-444
Summary A biotinylated P
0 glycoprotein cDNA was hybridized in situ to aldehyde-fixed vibratome sections and to aldehyde-fixed thin sections of Lowicryl-embedded trigeminal ganglia of 15 day old rats. Alkaline phosphatase and peroxidase detectors were used for light microscopic (LM) studies and peroxidase or colloidal gold were employed for electron microscopic (EM) detection. In both LM and EM sections, probe was found in cytoplasmic areas of myelinforming Schwann cells that were enriched in granular endoplasmic reticulum, demonstrating that these regions contain P
0 mRNA. Interestingly, P
0 mRNA tended to cluster in regions close to the developing myelin sheath. Relatively simple methods are here described for EM detection of mRNA with reasonable tissue preservation and high resolution. These methods may be useful for developmental and disease-related studies of specific mRNAs in mammalian tissues. 相似文献
2.
Alterations in tissue Mg++, Na+ and spinal cord edema following impact trauma in rats 总被引:3,自引:0,他引:3
M Lemke P Demediuk T K McIntosh R Vink A I Faden 《Biochemical and biophysical research communications》1987,147(3):1170-1175
Alterations in water content and total tissue Na+ and Mg++ of rat spinal cord tissue were followed over time after a 100 g-cm impact injury to the T-9 spinal cord segment. Rats subjected to laminectomy but not trauma served as controls. In the injured segment there was a progressive increase in water content with increased Na+ and decreased Mg++ at 1 hour and 24 hours after trauma. At seven days, water and Na+ content remained elevated, whereas Mg++ levels had returned to preinjury baseline values. Because of its important role in many metabolic and physiological regulatory processes the early decline in Mg++ concentration after trauma may contribute to the development of secondary tissue damage after spinal cord injury. 相似文献
3.
A Monte Carlo investigation of homogeneity tests of the odds ratio under various sample size configurations 总被引:2,自引:0,他引:2
Epidemiologic data for case-control studies are often summarized into K 2 x 2 tables. Given a fixed number of cases and controls, the degree of sparseness in the data depends on the number of strata, K. The effect of increasing stratification on size and power of seven tests of homogeneity of the odds ratio is studied using Monte Carlo methods. In all the designs considered here, the numbers of cases and controls per stratum are the same. Considering both size and power in non-sparse-data settings, we recommend the Breslow-Day statistic (1980, Statistical Methods in Cancer Research, 1. The Analysis of Case-Control Studies, p. 142; Lyon: International Agency for Research on Cancer) for general use. In sparse-data settings the T4 statistic of Liang and Self (1985, Biometrika 72, 353-358) performs the best when all tables, regardless of sample size, have odds ratios generated from the same distribution. In sparse-data settings characterized by a large table with an odds ratio of 1 and many small tables with odds ratios greater than 1, the T5 statistic of Liang and Self (1985) performs the best. One of the most important results of this study is the generally low power for all homogeneity tests especially when the data are sparse. 相似文献
4.
Zusammenfassung Anhand einer 16jährigen Untersuchung im Raum Ostwestfalen/Bielefeld wird der Bruterfolg des Turmfalken anhand von 439 Gelegen und 2256 Eiern beschrieben. Drei Brutplatztypen können unterschieden werden: A. Baumbruten in Nestern; B1. Baumbruten in Nistkästen; B2. Gebäudebruten in Nischen oder Nistkästen. Zwischen Baumbruten (A) und Nistkastenbruten (B1/2) werden signifikante Unterschiede beschrieben, die für Nistkästen größere Gelege (ca. ein Ei mehr) und größeren Ausfliegeerfolg belegen. Zwischen Nistkästen in Bäumen (B1) oder an Gebäuden (B2) konnten keine signifikanten Unterschiede festgestellt werden. Weiterhin werden Lege- und Schlupftermine, Legerhythmus und oologische Daten aus dem Untersuchungsgebiet angegeben.
Breeding biology of Kestrels (Falco tinnunculus) in Eastern Westfalia 1972–1987
Summary The 16 years of study gave 439 clutches with 2,256 eggs. We separated three types of breeding sites: the use of (a) stick nests, mostly built by corvids (cf. Tab., Fig. 3), (b1) nest boxes attached to trees or telegraph poles (Fig. 2) and (b2) nest boxes or cavities at or in buildings (Fig. 1). Within these different types of breeding places we found some significant differences. Stick nests had less eggs and though less breeding success, which was possibly caused by predation of corvids, especially magpies. Within the two types of places with nest boxes no significant differences could be established. We concluded, that stick nests were marginal in Kestrels and nest boxes were optimal despite of their placement in trees, at poles or in buildings. Furthermore, the timing of breeding cycle was described (Fig. 4) and laying interval was determind to an average value of approximately two days (Fig. 5). Mean egg size was and average volume 21.2 cm2. Two daily controlled clutches lost 15.5% and 16.1% of mass (Fig. 6) pressumably mostly due to water losses.相似文献
5.
Morten Glasø Olav Hilmar Iversen Torstein Hovig 《Virchows Archiv. B, Cell pathology including molecular pathology》1988,56(1):221-235
The nature and significance of so-called dark keratinocytes in the epidermis during chemical carcinogenesis is still a matter
of concern and debate. Based on ultrastructural observations it has been suggested that dark cells most often are shrunken
cells. Reports on skin carcinogenesis, however, claim that dark cells are a sign of ongoing tumor promotion and represent
those stem cells in the epidermis from which the tumors originate. It is therefore important to find out whether these cells
are simply injured and shrunken cells, or vital cells of great importance for carcinogenesis. Dark cells are assumed to be
rich in ribosomes. There is evidence, however, that the observed number of dark cells is highly dependent on tissue fixation.
In the present ultrastructural study, morphometric methods were used to compare the effects of two different fixation procedures
on the amount of cytoplasmic ribosomes in dark cells from both untreated and carcinogen-treated hairless mouse epidermis.
The results show that the ultrastructural features of both dark and clear cells vary considerably with different fixation
procedures. In acetone-treated controls typical dark cells are only observed when the fixative has a lower osmotic activity
than the plasma. With iso-osmolal fixation typical dark cells are not observed. After an abortive two-stage carcinogenesis
treatment, in which a single application of 9,10-dimethyl-l,2-benzanthracene (DMBA) in acetone was followed by a single application
of 12-O-tetradecanoyl-13-acetate (TPA) in acetone, signs of cell injury could be found after both fixation procedures. With
DMBA/TPA and hypo-osmolal fixation the number of dark cells seemed to increase, whereas only signs of cell injury with occurrence
of some heavily altered “clear cells” dominated the picture with iso-osmolal fixation. Morphometry showed that both the numerical
and the volumetric densities of cytoplasmic ribosomes in basal keratinocytes varied most significantly with the fixation procedure
used. The cytoplasmic volumes did not vary in a way that could explain these differences. One might therefore assume that
the number of ribosomes depends on the fixative. Large swelling artifacts occurred when a fixative with low osmotic activity
was used, leading to compression of neighboring cells. Hence, an increased ribosomal density reported previously in dark cells
is probably related to such cell volume artifacts and does not reflect an actually increased quantity of ribosomes. With both
fixation procedures, a single application of DMBA followed by one of TPA appeared to produce an increased number of ribosomes
in basal keratinocytes. When hypo-osmolal fixation was used, however, treatment with DMBA/TPA did not influence the cytoplasmic
volume or the numerical density of ribosomes, in dark cells. This might indicate that so-called dark keratinocytes following
DMBA/TPA treatment are functionally inactive cells that appear more vulnerable than active cells to compression during hypo-osmolal
fixation. 相似文献
6.
7.
Effects of sulfhydryl reagents on nitroglycerin-induced relaxation of bovine coronary artery 总被引:1,自引:0,他引:1
The mechanism whereby nitroglycerin relaxes vascular smooth muscle remains uncertain. A current hypothesis suggests that nitroglycerin reacts with critical cellular sulfhydryl groups to form an intermediate, which activates guanylate cyclase, resulting in cGMP accumulation and relaxation. This study investigated further the potential involvement of sulfhydryls in nitroglycerin-induced vascular smooth muscle relaxation by evaluating effects of a variety of sulfhydryl alkylating and reducing agents on responses to nitroglycerin and other relaxants in bovine coronary arterial strips submaximally contracted using 30 mM K. Whereas 10(-4) M 5,5'-dithiobis-(2-nitrobenzoic acid), 10(-5) MN-ethylmaleimide, and 10(-4) MN-naphthylmaleimide did not affect nitroglycerin-induced relaxation, 10(-4) MN-ethylmaleimide and 10(-4) M ethacrynic acid significantly inhibited relaxation induced by nitroglycerin. Both ethacrynic acid and N-ethylmaleimide at 10(-4) M also inhibited relaxation induced by sodium nitroprusside. N-ethylmaleimide, but not ethacrynic acid, inhibited relaxation induced by isoproterenol and forskolin. Ethacrynic acid significantly reduced both relaxation and cGMP elevation induced by both 10(-7) M nitroglycerin and 10(-7) M sodium nitroprusside. Ethacrynic acid, but not N-ethylmaleimide, significantly reduced relaxation induced by 8-Br-cGMP. Pretreatment with the sulfhydryl-containing agents N-acetylcysteine, 2-mercaptoethanol, or dithiothreitol, at 10(-3) M did not affect nitroglycerin-induced relaxation in nontolerant arteries. Similarly, N-acetylcysteine and dithiothreitol did not alter the depressed responses to nitroglycerin in arteries in which tolerance to nitroglycerin was induced in vitro. A slight but statistically significant reversal of nitroglycerin-tolerance occurred after treatment of tolerant arteries with 2-mercaptoethanol.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Summary A soluble enzyme with carbonic anhydrase activity has been isolated from domestic turkey(Meleagris gallopavo) erythrocytes and purified by chloroformethanol precipitation, ammonium sulfate fractionation and gel filtration on a Sephadex G-75 column. Analytical polyacrylamide gel disc electrophoresis showed one major and two minor bands. The specific activity for the CO2 hydration reaction was approximately 2000 Wilbur-Anderson units/mg protein at 0°C. The presence of the reducing agents 2-mercaptoethanol or dithioerythritol was required throughout the procedure. Upon removal of the 2-mercaptoethanol by dialysis the activity was lost but could be restored by addition of the reducing agent. The enzymatic activity was inhibited by acetazolamide,p-chloromercuribenzoate ando-iodosobenzoate. Esterase activity was detected withp-nitrophenylacetate as the substrate. The molecular weight of the enzyme was determined as 31,000 by gel filtration and 34,000 ± 2000 with analytical ultracentrifugation. Atomic absorption spectroscopy indicated the presence of zinc in the ratio of one mole of zinc per one mole of enzyme. 相似文献
9.
Sek4 and Nuk receptors cooperate in guidance of commissural axons and in palate formation. 总被引:12,自引:1,他引:11
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Sek4 and Nuk are members of the Eph-related family of receptor protein-tyrosine kinases. These receptors interact with a set of cell surface ligands that have recently been implicated in axon guidance and fasciculation. We now demonstrate that the formation of the corpus callosum and anterior commissure, two major commissural axon tracts that connect the two cerebral hemispheres, is critically dependent on Sek4 and Nuk. While mice deficient in Nuk exhibit defects in pathfinding of anterior commissure axons, sek4 mutants have defects in corpus callosum formation. The phenotype in both axon tracts is markedly more severe in sek4/nuk1 double mutants, indicating that the two receptors act in a partially redundant fashion. sek4/nuk1 double mutants also exhibit specific guidance and fasciculation defects of diencephalic axon tracts. Moreover, while mice singly deficient in either Sek4 or Nuk are viable, most sek4/nuk1 double mutants die immediately after birth primarily due to a cleft palate. These results demonstrate essential and cooperative functions for Sek4 and Nuk in establishing axon pathways in the developing brain, and during the development of facial structures. 相似文献
10.
Fibronectin (FN) turnover and turnover changes induced by the anticancer drug Adriamycin (ADR) were measured in human mesangial cells (HMC) in vitro. HMC cultures synthesize cellular FN (2.2+-0.3% of totalprotein synthesis; n = 12) which is secreted and incorporated into a fibrillar extracellular matrix (ECM). A 24 hr incubation of HMC with ADR (0.5–5 g/ml) resulted in an accumulation of FN in the culture medium, with a maximum increase following 5 pglml(7.3+-2.3pg/cell vs. controls: 4.4+-1.9pg/cell; n= 10). Correspondingly, radioactively labeled immunoprecipitable FN was increased in a dosage-dependent manner in the culture medium up to 50% vs. controls. The incorporation of radioactively labeled FN into ECM was significantly increased following 2 g ADR/ml. In accordance, immunofZuorescence staining revealed an expansion ofpericellular FNfibers in cultures exposed to 2 g ADR/ml. Concomitant with the accumulation of extracelhlar FN, radioactively labeled FN in the cells was reduced by 22%. Qualitative characterization of FN patterns revealed a diminished number of degradation products in the culture medium ofADR-treated HMC. These data suggest thatADR interferes with the turnover of FN secreted by HMC in vitro in such a way that FN accumulates extracellularly. This in turn leads to a reduced FN synthesis. These findings are compatible with a loss of urinary FN degradation products accompanying the onset ofproteinuria in ADR-treated rats.Abbreviations ADR
adriamycin
- BSA
bovine serum albumin
- DTT
dithiothreitol
- ECM
extracellular matrix
- EDTA
ethylenediamine tetraacetic acid disodium salt
- ELISA
enzyme-linked immunosorbent assay
- FCS
fetal calf serum
- FITC
fluorescein isothiocyanate
- FN
fibronectin
- HMC
human mesangial cell
- PBS
phosphate buffered saline
- PMSF
phenylmethylsulfonyl fluoride
- SDS
sodium dodecyl sulfate
- SDS-PAGE
SDS-polyacrylamide gel electrophoresis 相似文献