Morphological analysis of the adrenal cortex after bilateral subdiaphragmatic vagotomy

In Wistar rats 7 and 45 days after bilateral subdiaphragmatic vagotomy the zona fasciculata and zona reticularis of the adrenal cortex were enlarged and the content of unsaturated phospholipids in their cells was increased. In the medulla the venous sinusoids were greatly dilated. Administration of glucose to the vagotomized animals caused further accumulation of unsaturated phospholipids in the cells of the zona fasciculata but there was no change in the width of the zones. These facts indicate that after vagotomy precursors of steroid hormones accumulate; this is interpreted as a morphological sign of depression of functional activity of the zona fasciculata and zona reticularis of the adrenal cortex.Department of Histology and Embryology, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. M. Lopukhin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 9, pp. 1128–1130, September, 1976.     

Phospholipids and benzodiazepine recognition sites of brain synaptic membranes

Benzodiazepine binding to cerebral synaptic membranes and its modulation by membraneous phospholipids were studied. [³H]diazepam and [³H]flunitrazepam binding to the cerebral synaptic membrane were saturable and consisted of one component with a high affinity. Both [³H]diazepam and [³H]flunitrazepam binding was significantly decreased by pretreatment of the membrane with trypsin and pronase. In contrast, treatment of the membrane with phospholipase C and phospholipase A₂, induced a significant increase in binding. Kinetic studies have indicated that the treatment with phospholipase C induces an increase in density of the receptors, whereas treatment with phospholipase A₂ increases the affinity of the receptor. The addition of phospholipids, such as phosphatidyl serine and phosphatidic acid, abolished the increase in [³H]diazepam binding induced by phospholipase C and phospholipase A₂ treatment. The GABA-induced increase in [³H]diazepam binding was significantly attenuated following phospholipase A₂ treatment, but not in the control or in phospholipase C-treated membranes. In addition, the binding of [³H]flunitrazepam to the solubilized benzodiazepine receptor from the synaptic membrane was not affected by phospholipase C and phospholipase A₂ treatments.

The present results indicate that the benzodiazepine receptor binding in synaptic membranes is modulated, at least in part, by membraneous phospholipids susceptible to treatment with phospholipase C and phospholipase A₂.     

Structure-activity relationships of antineoplastic ring-substituted ether phospholipid derivatives

Purpose Previous studies have shown that alkylphosphocholines (APCs) exhibit strong antineoplastic activity against various tumour cell lines in vitro and in several animal models. The current study was designed to investigate the influence of cycloalkane rings on the antiproliferative activity of APCs against a panel of eight human and animal cell lines (PC3, MCF7, A431, Hela, PC12, U937, K562, CHO). Specifically, we explored the effect of the presence of 4-alkylidenecyclohexyl and cycloalkylidene groups in alkoxyethyl and alkoxyphosphodiester ether lipids, respectively. In addition, the haemolytic activity of the new ring-substituted ether phospholipids (EP) was evaluated.Methods Cells were exposed to various concentrations of the compounds for 72 h. The cytotoxicity was determined with the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] dye reduction assay. Similarly, red blood cells were distributed in 96-well microplates and treated with the test compounds at concentrations ranging from 100 to 6.25 M for 1 h. After centrifugation, the absorbance of the supernatants was measured at 550 nm.Results The majority of the compounds tested exhibited significant cytotoxic activity which depended on both the ring size and position with respect to the phosphate moiety, as well as the head group. Among the cycloalkylidene series the 11-adamantylideneundecyl-substituted N-methylmorpholino EP 13 was the most potent and exhibited broad-spectrum anticancer activity comparable to or superior to that of hexadecylphosphocholine (HePC). All the adamantylidene-substituted EPs were nonhaemolytic (concentration that exhibits 50% haemolytic activity, HC₅₀, >100 M). Furthermore, the cyclohexylidene-substituted analogues were more potent against the cell lines tested, with the exception of U937 and K562, than the cyclodecapentylidene-substituted compounds. Hydrogenation of the double bond in the cycloalkylidene-substituted EPs (compounds 14 and 15) resulted in improvement of anticancer activity. Among the 2-(4-alkylidenecyclohexyloxy)ethyl EPs, 2-(4-hexadylidenecyclohexyloxy)ethyl phosphocholine (22) possessed the highest broad-spectrum cytotoxic activity than all the other analogues of this series and was nonhaemolytic (HC₅₀ >100 M). In general, the 2-(4-alkylidenecyclohexyloxy)ethyl-substituted EPs were more active against the more resistant cell lines U937, K562 and CHO than HePC.Conclusions The presence of cycloalkane rings in the lipid portion of APCs reduces haemolytic effects compared to HePC and in several analogues results in improved antineoplastic activity.     

Glycosidated phospholipids: uncoupling of signalling pathways at the plasma membrane

Cell expansion and metastasis are considered hallmarks of tumour progression. Therefore, efforts have been made to develop novel anti-cancer drugs that inhibit both the proliferation and the motility of tumour cells. Synthetic alkylphospholipids, compounds with aliphatic side chains that are ether linked to a glycerol backbone, are structurally derived from platelet-activating factor and represent a new class of drugs with anti-proliferative properties in tumour cells. These compounds do not interfere with the DNA or mitotic spindle apparatus of the cell. Instead, they are incorporated into cell membranes, where they accumulate and interfere with lipid metabolism and lipid-dependent signalling pathways. Recently, it has been shown that the most commonly studied alkylphospholipids inhibit proliferation by inducing apoptosis in malignant cells while leaving normal cells unaffected. This review focuses on a novel group of synthetic alkylphospholipids, the glycosidated phospholipids, which contain carbohydrates or carbohydrate-related molecules at the sn-2 position of the glycerol backbone. Members of this subfamily also exhibit anti-proliferative capacity and modulate the cell adhesion, differentiation, and migration of tumour cells. Among this group, Ino-C2-PAF shows the highest efficacy and low cytotoxicity. Apart from its anti-proliferative effect, Ino-C2-PAF strongly reduces cell motility via its inhibitory effect on the phosphorylation of the cytosolic tyrosine kinases FAK and Src. Signalling pathways under the control of the FAK/Src complex are normally required for both migration and proliferation and play a prominent role in tumour progression. We intend to highlight the potential of glycosidated phospholipids, especially Ino-C2-PAF, as a promising new group of drugs for the treatment of hyperproliferative and migration-based skin diseases.     

Identification of an erythroid ATP-dependent aminophospholipid transporter

The asymmetric distribution of amino-containing phospholipids in plasma membranes is essential for the function and survival of mammalian cells. Phosphatidylserine (PS) is restricted to the inner leaflet of plasma membranes by an ATP-dependent transport process. Exposure of PS on the surface of cells serves as a binding site for haemostatic factors, triggers cell-cell interaction and recognition by macrophages and phospholipases. Exposure of PS on the red cell surface plays a significant role in sickle cell pathology. We report the identification of two different isoforms of the aminophospholipid translocase, Atp8a1, or flippase, in the murine red blood cell membrane.     

Simultaneous quantification of glycine- and taurine-conjugated bile acids,total bile acids,and choline-containing phospholipids in human bile using H NMR spectroscopy

Bile acids, phospholipids, and cholesterol are the major lipid components in human bile. The composition of bile is altered in various cholestatic diseases, and determining such alterations will be of great clinical importance in understanding the pathophysiology of these diseases. A robust method for the simultaneous quantification of major biliary lipids – glycine-conjugated bile acids (GCBAs), taurine-conjugated bile acids (TCBAs), total bile acids (TBAs) and choline-containing phospholipids (choline-PLs) has been devised using ¹H NMR spectroscopy. Bile samples were obtained from patients with various hepatopancreatobiliary diseases (n = 10) during an endoscopic retrograde cholangiopancreatography (ERCP) examination. Peak areas of metabolite-signals of interest were obtained simultaneously by deconvoluting the experimental spectrum, making the present method robust. GCBAs and TCBAs have been quantified using the peak areas of their characteristic methylene (CH₂) signals resonating at 3.73 and 3.07 ppm, whereas TBA and choline-PLs were quantified using their methyl (CH₃) and trimethylammonium (–N⁺(CH₃)₃) signals resonating at 0.65 and 3.22 ppm respectively. The present method was compared with an NMR-based literature method (which involves dissolving bile in DMSO), and a good correlation was observed between the two methods with regression coefficients – 0.97, 0.99, 0.98 and 0.93 for GCBAs, TCBAs, TBAs, and choline-PLs respectively. This method has the potential to be extended to in vivo applications for the simultaneous quantification of various biliary lipids non-invasively.     

Influence of chrysin on hepatic marker enzymes and lipid profile against d-galactosamine-induced hepatotoxicity rats

Chrysin is a flavonoid that exists in nature and is the major component of some traditional medicinal herbs. We investigated the hepatoprotective and antihyperlipidaemic potential of chrysin against d-galactosamine (a single intraperitoneal injection 400 mg/kg BW) induced hepatotoxicity in male albino Wistar rats. d-GalN rats exhibited an increased hepato and nephro toxicity marker activities aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and gamma glutamyl transpeptidase and total bilirubin level while urea, uric acid and creatinine and lipid profile. It also negatively affected the serum total protein, albumin and A/G ratio. Rats treated with chrysin at different concentrations (25, 50 and 100 mg/kg BW) caused a significant improvement in serum protein level, decreased hepato and nephro toxicity markers. It also decreased the levels of very low density lipoprotein cholesterol and low density lipoprotein cholesterol while high density lipoprotein cholesterol significantly increased. It also decreased the levels of total cholesterol, phospholipids, triglycerides, free fatty acids in the plasma and tissues of liver and kidney. The effect of chrysin (25 mg/kg) is comparable with silymarin, a known hepatoprotective drug. Chrysin thus exhibits hepatoprotective and antihyperlipidaemic activity.     

Beta-2-glycoprotein I and urinary trypsin inhibitor levels in the plasma of pregnant and postpartum women

Annexins (Anx) are a family of structurally related proteins that all bind to anionic phospholipids in a Ca(2+)-dependent manner. Some biological properties of beta-2-glycoprotein I (beta(2)-GPI) are similar to those of Anx IV and Anx V. Urinary trypsin inhibitor (UTI) helps to maintain normal pregnancy and prevent preterm delivery by inhibiting uterine contraction. However, plasma beta(2)-GPI and UTI levels have not been measured in normal pregnancy. The aim of this study is to clarify the levels of these parameters. Subjects were nonpregnant women (n=50), 120 pregnant women, and maternal subjects just after delivery (n=53) or postpartum (n=67). All of the subjects were healthy. Plasma levels of beta(2)-GPI, UTI, Anx IV, Anx V and other coagulation and fibrinolysis markers were measured by ELISA. The mean plasma level of beta(2)-GPI was significantly increased during the third trimester of pregnancy and 3 to 5 days after delivery. The mean plasma level of UTI was unchanged from the first trimester of pregnancy to the postpartum period. The mean plasma UTI level in vaginal delivery group was significantly higher than that in cesarean section group. beta(2)-GPI protein was expressed in some of the syncytiotrophoblasts. These data suggest that beta(2)-GPI might act to prevent blood clotting on the placental surfaces and also prevents disseminated intravascular coagulation in the microcirculation and maternal plasma. UTI levels might be kept constant by increased urinary excretion despite overproduction during pregnancy.     

An analysis of data on human hepatic bile. Relationship between main bile components,serum cholesterol and serum triglycerides

Hepatic bile samples were taken from the common duct during interval operations for gallstone disease, performed under standardized conditions. Prior to operation serum cholesterol and triglycerides levels were determined. The concentrations of Cholesterol (Chol), phospholipids (Lip P) and of the three major bile acids (BA) were determined in ninety-seven samples. The data were subjected to statistical analysis. A highly significant rank correlation was found between the Chol- and the Lip P molar fractions. The rank correlation between the Chol molar fraction and the BA/Lip P ratio was highly significantly negative. Reasons are given why the observed intraindividual differences are interpreted as reflecting interindividual changes. The conclusion is that just as in the animal model, a rise of Chol in human hepatic bile is accompanied by a decrease of the BA/Lip P ratio. A significant correlation was found between chenodeoxycholic acid (CDCA), and the ratio between the two other main bile acids (CA/DCA). High lithogenicity was associated with low CDCA- and high DCA values. In a mathematical representation valid in the sense of a rank correlation, the bile/serum Chol ratio rose with increasing DCA values combined with increasing absolute differences between the two other acids. Serum triglycerides were negatively correlated with the BA molar fraction and with the absolute concentration of BA. As a result there was an association between serum triglycerides and lithogenicity.