摘要:

AbstractIn a companion paper13we demonstrated that normal peripheral blood granulocytic precursor cells differentiate after 2–3 weeks in suspension culture. In the studies described here leukemic blast cells obtained from 14 patients with acute myelocytic leukemia (AML) and two patients with chronic myelocytic leukemia in blastic crisis were cultured in McCoy's 5A medium containing 15 per cent fetal bovine serum for 2–3 weeks at 37°C in an atmosphere of 5 per cent CO2–95 per cent room air. ‘Spontaneous’ myeloid differentiation (20 × 104viable mature myeloid cells ml−1) occurred in the cultures of cells obtained from 8 pts. The differentiation was granulocytic in three cases, monocytic in four cases and of mixed type in one case. Differentiation was independent of the growth of the cells in culture and occurred in four cases after the first week. Monocytic differentiation was seen only in AML of the FAB M4 type whereas granulocytic or mixed differentiation were seen only in AML of the FAB M1 or M2 types. When PHA leucocyte conditioned medium (PHA‐LCM) was added to the cultures monocytic/macrophage differentiation was favoured. Inducers of the differentiation of the HL‐60 cell line (N‐methylacetamide, cytosine arabinoside, or retinoic acid) had no consistent effect on the differentiation and were at times inhibitory. Three patients received therapy with low dose cytosine arabinoside and no correlation was observed between the outcome of the treatment and leukemic cell differentiation in culture in the p

ISSN:0263-6484    

DOI:10.1002/cbf.290050302

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractAddition of an amphiphilic lipid, such as phosphatidylcholine (PC) species with two identical saturated chains or lysophosphatidylcholine (lysoPC) species with one saturated acyl chain of various lengths, into a suspension of intact human erythrocytes resulted in lipid incorporation into the erythrocyte membrane to produce echinocytes (crenated cells). The altered shape gradually reverted on incubation at 37°C until the cells reassumed their normal disc shape. The rate of such recovery of shape increased with decreasing acyl chain length for both PC with C8–C12acyl chains and lysoPC with a C14–C18acyl chain, and was strongly influenced by incubation temperature. The identical rate of recovery of shape was observed for cells with normal, decreased or increased ATP content, implying that the metabolic state of the cell had no influence on the recovery process. Recovery of shape is therefore considered to be caused by translocation of the incorporated lipid molecules from the outer to the inner leaflet of the membrane lipid bilayer and the rate of recovery increases with decreasing hydrophobicity of the l

ISSN:0263-6484    

DOI:10.1002/cbf.290050303

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractExtracellular acylglycerols are hydrolysed by lipases active at the surface of intact fat cells isolated from rat or human adipose tissue. During short‐term incubation, rat fat cells hydrolyse di‐[3H]oleyl‐[14C]glycerol at a rate of 70 ± 7·7 mU/106cells (means ± S.E.) versus 440 ± 62 mU/106cells for the hydrolysis of mono‐[3H]oleylglycerol; these relatively high lipolytic potencies may serve, among other functions, to counteract the cytolytic effect of both esters. Reaction rates with both substrates are unchanged by addition of various apolipoproteins C and by the nutritional state of the animals. Fat cells incorporate 15–20 per cent of the total [3H]‐oleic chains liberated by hydrolysis, with no correlation between uptake and hydrolysis rates. [3H]‐oleic chains in cell lipids are found mainly as diacylglycerol (15 per cent) and triacylglycerol (80 per cent). Both lipolytic processes differ from the hydrolysis of trioleyglycerol by cell‐bound lipoprotein lipase, which occurs at lower rates (6·5 ± 0·6 mU/106cells) and depends on apolipoprotein C‐II and nutritional state of the animals. The results support the accepted view that lipoprotein lipase and monoacylglycerol lipase are distinct enzymes. Differences between lipoprotein lipase and diacylglycerol lipase activities raise the possibility of different catalytic entities. In conclusion, isolated fat cells in suspension hydrolyse and incorporate lipids. This model should approximate physiological conditions more closely than the use of l

ISSN:0263-6484    

DOI:10.1002/cbf.290050304

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractCytochalasin B (17·3 μM) virtually abolished 3‐O‐methyl‐D‐[U‐14C]glucose uptake andD‐[5‐3H]glucose utilization in tumoral insulin‐producing cells of the RINm5F line. This coincided with a marked decrease inD‐[U‐14C] glucose oxidation and suppression of the stimulant action ofD‐glucose upon insulin release. Cytochalasin B, however, augmented basal insulin release by the tumoral cells. The RINm5F cells appeared much more sensitive than normal islet cells to cytochalasin B, as judged by the relative magnitude of inhibition in either hexose uptake or utilization. In both cell types, the inhibitory action of cytochalasin B upon glucose metabolism seemed to be competitive, being more marked at low than high glucose concentration. These results are interpreted in support of the view that a decreased efficiency of hexose transport across the plasma membrane represents an essential deficie

ISSN:0263-6484    

DOI:10.1002/cbf.290050305

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractPentanal and hexanal are some of the aldehydes produced by lipid peroxidation, that causes damage to several subcellular structures. Lipoperoxidation products may directly attack cytoskeletal structures, the integrity of which is required for secretion mechanisms, e.g. 4‐hydroxy‐alkenals alter microtubular integrity and function.Purified microtubular protein incubated with pentanal and hexanal at different concentrations revealed a tubulin–aldehyde interaction affecting the polymerization reaction and the colchicine‐binding activity.These reactions apparently do not involve sulphydryl groups, and the addition of mercaptoethanol does not protect microtubules from the action of aldehydes, the effect of which is however more homogeneous, as only small differences can be noticed among the various aldehyde concentratio

ISSN:0263-6484    

DOI:10.1002/cbf.290050306

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractHepatocytes actively involved in albumin synthesis were identified by immunohistochemical method. In sections of perioidate–lysine–2 per cent (w/v) paraformaldehyde fixed normal rat liver, albumin was detected in all hepatocytes. At the untrastructural level, albumin was localized in the rough endoplasmic reticulum and in Golgi complexes located near the nucleus in only a small subpopulation of hepatocytes, while all other hepatocytes contained albumin only in Golgi complexes located near the bile canaliculi. Stimulation of albumin synthesis by puromycin aminonucleoside‐induced nephrosis resulted in an altered intracellular distribution of albumin at the light microscopic level. When examined at the ultrastructural level, albumin was localized in the rough endoplasmic reticulum as well as in Golgi complexes located near the nucleus in nearly all these hepatocytes.Hepatocytes with the potential to synthesize albumin were identified byin situhybridization of albumin mRNA. In sections of 0·1 per cent (v/v) glutaraldehyde perfusion fixed normal rat liver, albumin mRNA was detected in the cytoplasm of only a few hepatocytes scattered throughout the lobule. Following stimulation of albumin synthesis by the induction of nephrosis, albumin mRNA was detected in the cytoplasm of the hepatocytes.The source of albumin in those hepatocytes which lacked albumin mRNA was identified in analbuminemic rats injected with rat albumin. At 6 h post injection, the light microscopic distribution of albumin in the liver of these animals was virtually indistinguishable from that in normal rat liver. At the ultrastructural level, injected albumin was localized in lysosomes and in Golgi complexes located near the bile cana

ISSN:0263-6484    

DOI:10.1002/cbf.290050307

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractIt was found that chronic intoxication of rats with ethanol results in an increase of prolyl hydroxylase activity in liver and serum of the experimental animals. The increase of enzyme activity precedes the morphological symptoms of liver damage. The possibility arises that the assay of prolyl hydroxylase in serum or in liver biopsy samples could be useful for the diagnosis of the tendency of some individuals to develop liver cirrhosis induced by ethanol.

ISSN:0263-6484    

DOI:10.1002/cbf.290050308

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThis study was conducted to follow as a function of time the activity of gamma‐glutamyltransferase in the various membranes of rat liver cells after a single dose of phenobarbital (PB) (75 mg kg−1body weight). Gamma‐glutamyltransferase induction was maximal 24 h after PB treatment in both the rough endoplasmic reticulum and the plasma membranes. This pattern of induction differed from that of some drug metabolizing enzymes. While total cytochrome P‐450 content was enhanced mainly in endoplasmic reticulum until 48 h after PB treatment, UDP‐glucuronosyltransferase activity was not greatly altered by PB under the same conditions.The comparison of two‐dimensional electrophoretic polypeptide profiles of each subcellular membrane isolated from control and phenobarbital‐treated rats revealed important variations induced by PB. In plasma membranes, the heaviest subunit (apparentMr= 60 × 103) of hepatic gamma‐glutamyltransferase was provisionally identified as a collection of polypeptides which differ only by their pI. The concentration of these polypeptides was smaller in the endoplasmic reticulum where they were of lower apparent molecular mass. This suggests that the gamma‐glutamyltransferase precursor is already processed at the level of the endoplasmic reticulum but it is still not completely mature or glycosylated. Five days of continuous PB treatment induced the appearance of new gamma‐glutamyltransferase isoforms in plasma membranes.We demonstrate that after a single injection of PB, gamma‐glutamyltransferase activity increases simultaneously with some drug‐metabolizing enzymes, such as total cytochrome P‐450 but not with others, such as UD

ISSN:0263-6484    

DOI:10.1002/cbf.290050309

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290050311

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290050301

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY