ISSN:0263-6484    

DOI:10.1002/cbf.290020202

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractIn vitro, poorly iodinated thyroglobulin (Tg) is hydrolysed at the same rate whether it is enclosed in thyroid or in liver lysosomes, while fully iodinated Tg is degraded faster inside liver lysosomes. After in vivo TSH administration, thyroid lysosomes hydrolyse fully iodinated Tg as fast as do liver lysosomes.

ISSN:0263-6484    

DOI:10.1002/cbf.290020203

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractCharacteristics of taurine transport in rat hepatocytes maintained in primary culture for 24 h (cultured hepatocytes) have been investigated. The uptake of [3H] taurine by cultured hepatocytes at 2°C was unsaturable, whereas that at 37°C consisted of unsaturable and saturable processes. The saturable transport system was sodium‐dependent and consisted of two processes with low and with high affinities. The latter process (Km, 76.9 μM;Vmax, 0.256 nmole/mg protein/min; activation energy (EA), 37.8 kcal mol−1) was competitively inhibited by 2,4‐dinitrophenol and ouabain, as well as by taurine analogues such as hypotaurine and guanidinoethyl sulphonate. TheVmaxandEAvalues found in cultured hepatocytes at 37°C were 6.0 and 6.8 times higher than those found in freshly isolated hepatocytes. These results indicate that taurine transport in hepatocytes in primary culture consisted of unsaturable, and saturable, sodium and energy‐dependent carrier‐mediated transport processes, respectively. The facilitation of the latter transport system by primary culture of hepatocytes is a

ISSN:0263-6484    

DOI:10.1002/cbf.290020204

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractChicken liver and erythrocyte nuclei were separated by mild treatment with micrococcal nuclease into nuclease sensitive (NS) and nuclease resistant (NR) fractions, differing in chemical composition and transcriptional activity in vitro. Nuclei, NS and NR fractions of both tissues were fractionated by hydroxyapatite chromatography into three groups of non‐histone chromatin proteins (NHCP) and characterized by SDS‐polyacrylamide gel electrophoresis. Some differences in the molecular distribution of non‐histone proteins of chicken liver and erythrocytes between nuclease sensitive and resistant parts of chromatin have been desc

ISSN:0263-6484    

DOI:10.1002/cbf.290020205

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractSilymarin and silibyn are extracted from the seeds ofSilybum marianumand used as a liver protectant because of their free radical scavenging. When incorporated into rabbit liver microsomes they cause a small decrease in the flourescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatrine (DPH) but not of 1‐anilinononaphthalene‐8‐sulphonic acid (ANS), incorporated into the membranes. They do, however, reduce the fluorescence intensity of incorporated ANS without changing the wavelength of maximum intensity. These observations suggest that the drugs are incorporated into the hydrophobic–hydrophilic interface of the microsomal bilayer and perturb the structure by influencing the packing of th

ISSN:0263-6484    

DOI:10.1002/cbf.290020206

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe mechanism of the lysis of target cells by cytotoxic T‐cells (Tc) is still obscure; there is no evidence for transfer of material from the Tc and prior to lysis, despite intimate contact, the plasma membranes of both types of cell appear to remain intact. The effects on the target cell lysosomes of brief contact between anti‐viral Tc and targets bearing both the appropriate histocompatibility and viral antigens, have been examined cytochemically. Both the distribution of acid phosphatase activity and the percentage bound lysosomal naphthylamidase activity indicated that, in virus‐infected target cells exposed to Tc, the lysosomal membranes became totally labilized. Thus the contact between Tc and targets appears to cause sufficient perturbation of the target plasma membrane as to cause the intracellular release of some agent that activates ‘suicide capsule’

ISSN:0263-6484    

DOI:10.1002/cbf.290020207

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractRat intestinal epithelial cells were isolated by EDTA‐chelation, combined with gentle shaking (modified Weiser procedure) or with strong longitudinal vibration (Harrison/Webster procedure). Both methods yield large numbers of viable cells and are relatively easy to use. Electronmicroscopical and biochemical data indicate that cell fractions from different levels of the villous region can be obtained only by the modified Weiser procedure. When strong mechanical forces are involved (Harrison‐Webster procedure) the villus epithelium is released according to an all‐or‐nothing process. The biotransformational capacity of cell fractions, obtained from different levels of the villi by the modified Weiser procedure, was investigated. It was shown that the rate of metabolism of 7‐ethoxycoumarin and 1‐naphthol was substantially higher in lower villous cells than in cells isolated from the upper villous region. O‐Deethylation of 7‐ethoxycoumarin decreases from 145 ± 13 pmole/min mg cell protein (72 ± 4% conjugated) in lower villous cells to 62 ± 12 pmole/min mg cell protein (37 ± 6% conjugated) in tip cells. Glucuronidation of 1‐naphthol decreased from 495 ± 23 pmole/min mg cell protein (lower villous cells) to 137 ± 13 pmole/min mg c

ISSN:0263-6484    

DOI:10.1002/cbf.290020208

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractIn order to correlate the biochemistry of cell surface carbohydrates with cell function, we have treated cells with swainsonine and followed the biochemical and functional modifications induced by this compound. After treatment with swainsonine, surface glycoproteins had a lower apparent molecular weight and a higher isoelectric point. This is compatible with the replacement of complex carbohydrates by hybrid or high‐mannose carbohydrates. Several functional tests were unaffected. However, swainsonine‐treated cells displayed an altered pattern ofin vivohoming, suggesting that carbohydrates play a role in this proc

ISSN:0263-6484    

DOI:10.1002/cbf.290020209

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of thyroid hormones (T4, T3 and reverse T3) on rat renal Na+, K+‐ATPase activity was investigated by a cytochemical technique. T3 caused stimulation of Na+, K+‐ATPase activity in the renal medulla but not in the renal cortex. There was a peak in enzyme activity after cultured renal segments had been exposed to T3 for 11 min and this time of maximal stimulation did not vary with the concentration of T3. A rectilinear response in Na+, K+‐ATPase activity was observed over T3 concentration range 10 pmol l−1to 100 nmol l−1; at higher T3 concentrations, Na+,K+‐ATPase activity was inhibited. The enzyme response was totally blocked by specific T3 antiserum. Addition of T4 and reverse T3 (100 fmol l−1− 1 mmol l−1) failed to stimulate Na+,K+‐ATPase activity in any part of the kidney. Plasma (neat and diluted 1:10) stimulated the enzyme in parallel with the dose response curve and the stimulatory effect was abolished by prior addition of sp

ISSN:0263-6484    

DOI:10.1002/cbf.290020210

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe content of hepatic cyclic AMP was increased soon after intoxication by white phosphorus. Its level reached a maximum 4 h after poisoning, but in subsequent phases tended to return to normal. In contrast, the cyclic GMP concentration was altered only 24 and 36 h after treatment with the same hepatotoxin. Similar modifications of cAMP and cGMP content were also detected after poisoning by trichlorobromomethane (CBrCl3). As a consequence, an altered cGMP/cAMP ratio was found in both experimental conditions. Further, the modification of cAMP content after white phosphorus was detected prior to liver damage (steatosis and necrosis), while the highest concentration of the cyclic nucleotide in CBrCl3‐poisoned rats was found when fatty liver was already evident. In addition, in phosphorus‐poisoned rats, the hepatic content of Ca2+was found to be unmodified during all phases of the intoxication, while after CBrCl3a phasic increase of the Ca2+level was observed at 4, 24 and 3

ISSN:0263-6484    

DOI:10.1002/cbf.290020211

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY