Leukotriene D4 treatment of bovine aortic endothelial cells and murine smooth muscle cells in culture results in an increase in phospholipase A2 activity

Leukotriene D4 stimulates prostanoid synthesis in smooth muscle and endothelial cells. Because phospholipases A2 and C have been proposed to regulate prostanoid synthesis, we examined the effect of leukotriene D4 on these activities. Leukotriene D4 treatment resulted in a dose-dependent, stereospecific increase in phospholipase A2 activity with phosphatidylcholine as a substrate. The induction of phospholipase A2 activity occurred just prior to the appearance of prostanoids in the media. Protein and RNA synthesis were required for the increase in phospholipase A2 activity, and the increase in activity resulted from an increase in the apparent Vmax of the phospholipase A2 enzyme. Phospholipase C activity using various substrates was unchanged. We conclude that the increase in prostanoid synthesis observed after leukotriene D4 treatment is a result of an increase in a phospholipase A2 activity.

Comparison of single-dose vs one-week course of metronidazole for symptomatic bacterial vaginosis

In a prospective, single-blind, randomized study, a single 2-g dose of metronidazole was compared with a seven-day course of 500 mg given twice daily in the treatment of symptomatic vaginal discharge associated with Gardnerella vaginalis. Based on resolution of symptoms and on cultures negative for G vaginalis, 86% (40/46) of women treated with the single dose and 97% (35/36) of women treated with the seven-day course were considered cured at seven to ten days after treatment. Evaluation at 21 days after treatment, however, indicated that only 46% (16/34) of patients treated with the single 2-g dose were considered cured compared with 86% (26/30) of those treated with the seven-day course. Treatment of sexual contacts did not significantly improve cure rates in either group.

Effect of inhibitors of the lipoxygenase pathway on mouse myoblast fusion

In this study we examined the effects of inhibitors of the lipoxygenase and cyclooxygenase pathways on mouse myoblast fusion. The fusion of cloned mouse myoblasts was markedly inhibited, in a dose-dependent manner, when cells were cultured in medium supplemented with either phenidone (1-phenyl-3-pyrazolidione) or BW755c (3-amino-1-(3-tri-fluoromethylphenyl)-2-pyrazoline), drugs which have been reported to inhibit lipoxygenase and cyclo-oxygenase activities. Fusion was also inhibited when these cells were cultured in medium supplemented with esculetin (6,7-dihydroxycoumarin) which has been reported to inhibit lipoxygenase activity. Removal of the above inhibitors resulted in a return to control levels of fusion. Fusion was not demonstrably inhibited with aspirin (acetylsalicylic acid) and only inhibited to a minor extent with indomethacin (1-(p-chlorobenzoyl)-5-methoxy-2-methylindole-3-acetic acid); both of these drugs are inhibitors of cyclo-exygenase activity.

The effect of rapid eye movement sleep deprivation on cortical beta-adrenergic receptors

The relationship between rapid eye movement sleep deprivation (REMD) and rat beta-adrenergic receptors was evaluated. REMD was achieved using the platform method and verified by EEG and EMG recordings. Although the amount of REM sleep was diminished 90%, there was no alteration in either the number of binding sites or their affinity for [3H]-dihydroalprenolol. Periods of stress as well as recovery periods after REMD were also without effect on the cortical beta-adrenergic receptors. Thus no support is garnered for the interaction of REMD and the cortical beta-adrenergic receptor binding parameters, although REMD is sometimes used as a mode of therapy for depression and other antidepressives do in fact affect the beta-adrenergic system. The mechanism of REMD as a potential antidepressive therapy is yet to be elucidated.

Trapping of the beta-adrenergic receptor in the hormone-induced state

Isoproterenol and other agonists readily dissociate from the beta-adrenergic receptor in turkey erythrocyte membranes. However, when a low concentration of deoxycholate is added, the receptor locks the prebound agonist; i.e., the rate of dissociation of the prebound agonist decreases drastically. The dissociation of prebound antagonists is slightly increased by deoxycholate. Locking, which is thus agonist specific, occurs in the cold, is reversed when detergent is removed from the membranes, and appears not to require the guanyl nucleotide binding protein of the adenylate cyclase system. It is suggested that this induced fit of a receptor to an agonist represents the specific conformational response that normally propagates in the receptor molecule in its interaction with the next component along the pathway of signal transmission.

Follow-up study of 281 schizophrenic patients treated with high dosage fluphenazine decanoate

281 newly admitted female schizophrenic patients were treated with high dosage fluphenazine decanoate intramuscularly, starting with 250 mg per injection together with antiparkinsonian and antidepressant drugs. On a set day the 3 groups 'with neuroleptics' (NL) (n = 54), 'without NL' (n = 152) and 'relapsed when without NL' (n = 42) were compared concerning age, diagnosis, hereditary disposition, first admission and readmissions, number of admissions and global judgement. From the differences no clear conclusion for practical clinical work could be obtained. The good tolerance is discussed using the list of side effects including tardive dyskinesia and laboratory data.

Effects of sodium butyrate on the membrane glycoconjugates of murine sarcoma virus-transformed rat cells

The temporal relationship between butyrate-induced cellular flattening of murine sarcoma virus-transformed rat cells (MSV-NRK) and alterations in certain surface-associated biochemical markers of transformation, e.g., surface glycopeptides, glycolipids, fibronectin, hexose uptake, and cell-substrate adhesion was examined. The induction of elevated levels of the ganglioside GM3 and of a GDla-like ganglioside were observed to precede or to parallel cellular flattening. Likewise, enhanced incorporation of radioisotopically labeled fucose into a novel fucose-containing component, i.e., glucopyranosyl (1 leads to 3) fucopyranosyl-threonine, was also observed to occur at an early stage of cellular flattening. In contrast, a shift in the molecular weight distribution of trypsin-sensitive, surface fucopeptides was observed to occur at a late stage of cellular flattening. Moreover, surface fibronectin was not detectable in the butyrate-flattened MSV-NRK cells despite the fact that the cells manifested significantly enhanced cell-substrate adhesion. Thus, butyrate appears to be a useful tool for understanding the sequential changes associated with expression of the transformed phenotype of MSV-NRK cells.

Cyclic AMP-induced morphological transformation of cells infected by temperature-sensitive mouse sarcoma virus. Expression of transformation-associated markers

Normal rat kidney (NRK) cells infected with a temperature-sensitive (ts) mutant of mouse sarcoma virus (NRK [MSV-1b]) express the transformed phenotype when grown under permissive conditions, but acquire the normal phenotype when grown under restrictive conditions. Addition of 3', 5' cyclic adenosine monophosphate (cAMP) to NRK (MSV-1b) cells grown at the restrictive temperature results in morphological transformation. To determine whether other markers associated with the transformed phenotype were coordinately expressed after cAMP exposure, concanavalin A (Con A) agglutinability, hexose transport rate, and incorporation of radioactively labeled fucose into fucolipid III and fucolipid IV (FL III and FL IV ) of the cells were examined. NRK cells transformed by wild-type MSV or NRK(MSV- 1b) grown under permissive conditions were agglutinated by low concentrations of Con A and exhibited relatively high maximal agglutination levels which were specifically inhibited by alpha-methyl-D-mannoside. In contrast, NRK (MSV-1b) cells grown under restrictive conditions were weakly agglutinated by Con A and exhibited reduced maximal agglutination levels, similar to uninfected NRK cells. Treatment of NRK (MSV-1b) cells at the restrictive temperature with cAMP resulted in morphological transformation and a change in the pattern of incorporation of labeled fucose inot FL III and FL IV to one comparable to that of NRK (MSV-1b) cells at the permissive temperature or to NRK cells transformed by wild-type MSV. In contrast, cAMP treatment resulted in no increase in Con A agglutinability or 2 deoxy-D- [(3)H]glucose transport relative to mock treated cultures. The results demonstrate that cAMP-induced morphological transformation and altered fucolipid composition of NRK (MSV-1b) cells are not correlated with alterations in hexose transport rate or Con A agglutinability.

Fucolipid metabolism as a function of cell population density in normal and murine sarcoma virus-transformed rat cells

The incorporation of isotopically labeled fucose into the lipids of normal and murine sarcoma virus-transformed rat cells as a function of cell population density was examined. When normal cells were seeded at low cell density, the levels of the major fucolipids, i.e., fucolipids III and IV, were substantially reduced, but then they increased as the cells approached confluency. This variation in synthesis of fucolipids III and IV appeared to be primarily related to cell density and not to cell growth. Chase experiments revealed that the reduced level of fucolipids III and IV in sparse normal cells is due to decreased synthesis rather than to increased catabolism. In contrast to the observations with normal rat cells, the high level of fucolipid III and the low level of fucolipid IV in murine sarcoma virus-transformed rat cells was shown to be independent of cell population density.

Factors involved in concanavalin A agglutination of KB and NC37 cells grown in suspension culture

NC37 and KB cells grown in suspension culture remained agglutinable at 23 degrees C by concanavalin A (Con A) after sufficient glutaraldehyde fixation to prevent lateral mobility (clustering) of Con A binding sites. In contrast, at 4 degrees C agglutination of the fixed cells was blocked. No significant differences in 3H-Con A binding were observed between unfixed cells and glutaraldehyde-fixed cells at 23 degrees C and unfixed cells at 4 degrees C. Con A bound to fixed cells at 4 degrees C produced agglutination when the cells were washed and then warmed to 23 degrees C. Thus a cold-sensitive factor unrelated to the binding of Con A or the clustering of Con A sites is necessary for agglutination to occur.

Altered microfilament structure in cells transformed with a temperature-sensitive transformation mutant of murine sarcoma virus

The structure and distribution of microfilaments were examined by electron microscopy in uninfected normal rat kidney (NRK) cells, murine sarcoma virus (MSV)-transformed NRK cells, and NRK cells infected with a cold-sensitive transformation mutant of MSV, i.e., NRK (MSV-1b) cells, grown at both permissive (39 degrees) and nonpermissive (33 degrees) temperature. The uninfected cells contained numerous microfilaments which were especially prominent at sites of intercellular adherens junctions. In contrast, the MSV-transformed cells contained few microfilaments and did not form adherens junctions. At 33 degrees, the NRK (MSV-1b) cells appeared normal but formed an altered form of adherens junction with disorganized microfilaments. At 39 degrees, these cells resembled NRK cells transformed by wild-type MSV but still formed a few of the altered type of adherens junctions. Disorganized adherens junction microfilaments were also found in cells newly infected with wild-type MSV. These results suggest that the perturbed assembly of microfilaments at adherens junctions may be an intermediate stage in the loss of adherens junctions during viral transformation.

1-H and 13-C nuclear magnetic resonance spectra of the lipids in normal and SV 40 virus-transformed hamster embryo fibroblast membranes

Well resolved 1-H and 13-C NMR spectra were obtained with normal and SV 40-transformed cell membranes. Estimation of the ratio of 13-CT2 values of the normal to transformed cell membranes showed an increased intermolecular motion in the transformed cell membranes. The temperature dependence of the (CH2) line in the 1-H spectra in the temperature range 298-343 degrees K shows an activation energy for the lateral diffusion of the fluid phospholipid regions in the normal cell membranes while the transformed ones show practically no temperature dependence in this temperature range. The fluidity of the phospholipid region in the transformed cell membrane seems to be significantly higher than that observed in the normal cell material. These data support and extend the findings concerning the mobility of the concanavalin A binding/agglutinating sites on the surface of normal and virus-transformed cells and suggest further approaches to the study of the membrane alterations in tumor cells.

Fucolipid patterns of cell lines transformed by highly and weakly tumorigenic simian virus 40 and herpes simplex virus

The fucolipids of simian virus 40 (SV40)-transformed Balb/c mouse and herpes simplex virus (HSV)-transformed hamster cells of varying degrees of tumorigenicity were examined. In the virus-transformed cell lines and in a spontaneously transformed cell line, as compared to non-transformed cell lines, there was a decrease in the incorporation of fucose radioactivity into fucolipid IV. Fucolipid IV is the least chromatographically mobile, presumably most complex fucolipid. Only in the highly transplantable SV40- and HSV-transformed cell lines was the decrease in incorporation of radioactivity in fucolipid IV as marked as that observed in oncornavirus-transformed cell lines. Similarly, only in the highly tumorigenic DNA-virus-transformed cell lines was there a significant increase in incorporation of radioactivity from radioisotopically-labeled fucose into fucolipid III as has been observed in oncornavirus-transformed cell lines.

Major polar lipids of hepatitis B antigen preparations: evidence for the presence of a glycosphingolipid

The major phospholipids of hepatitis B antigen, subtype adw, were characterized as phosphatidylcholine, sphingomyelin, and lysophosphatidylcholine. In addition, two carbohydrate-containing lipids were observed, one of which was characterized as a non-sialic acid-containing, water-soluble glycosphingolipid. Upon hydrolysis the glycosphingolipid yielded both hydroxy and non-hydroxy fatty acid as well as a long-chain base which was putatively identified as dihydrosphingosine.

Inhibition of cardiolipin synthesis following infection with herpes simplex virus

The results of this study show that the synthesis of the inner mitochondrial membrane phospholipid, cardiolipin, is markedly inhibited following infection of human embryonic lung or hamster embryo fibroblast cells with herpes simplex virus type 1 or 2. The synthesis of other phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylinositol, is relatively unaffected.

Occurrence of phosphonosphingolipids in Bdellovibrio bacteriovorus strain UKi2

The major phospholipids of two strains of Bdellovibrio bacteriovorus were characterized. Both strain UKi1, which is obligately saprophytic, and strain UKi2, which is facultatively parasitic, contained phosphatidylethanolamine and phosphatidylglycerol as their major glycerophosphatides. A branched, 15-carbon fatty acid is the major component of these alkali-labile lipids. Absent from UKi1 but present in UKi2 were three alkali-stable lipids (compounds 8, 9, and 11) which appear to be phosphosphingolipids. After acid hydrolysis, both compound 8 and 9 yield the identical phosphorus-containing substance that is water soluble, dipolar ionic, and ninhydrin positive. This substance appears to contain a C-P bond since P(i) could not be released from this substance by treatment with alkaline phosphatase or by very harsh mineral acid treatment. Based on chromatographic comparisons, this phosphonate appears to be a novel lipid constituent. Upon degradation, compound 8 yields 1 mol of dihydroxy long-chain base and compound 9 yields 1 mol of a trihydroxy long-chain base. These bases appear to have a 17-carbon, possibly branched, structure based on gas-liquid chromatography retention times. Degradation of both sphingolipids yields a mixture of hydroxy fatty acids, the major component being a branched, 15-carbon hydroxy acid.

Studies on the diversity of inositol-containing yeast phospholipids: incorporation of 2-deoxyglucose into lipid

Seven inositol-containing phospholipids in Saccharomyces cerevisiae can be resolved by two-dimensional chromatography on silicic acid-impregnated paper. Four of these lipids are stable to mild alkaline methanolysis; one of these has already been characterized as a mannosyl di(inositolphosphoryl) ceramide. Addition of labeled 2-deoxy-d-glucose to a growing culture results in label appearing in five lipids, some of which are alkali-stable and have the same R(F) values as the alkali-stable inositol-containing phospholipids. These lipids are labeled rapidly. The deoxyglucose is incorporated intact, probably in a glycosidic link, since the deoxyglucose is released by mild acid treatment.

Polar lipids of Chromatium strain D grown at different light intensities

The total amount and the composition of polar lipids of the photosynthetic bacterium Chromatium strain D grown in high (7,500 ft/c) and low (100 ft/c) incident white light were measured. Cells grown with low incident light as compared with cells grown in high incident light contained approximately 3.5 times more chlorophyll and contained significantly more internal membranes (chromatophores) as determined by electron microscopy. Nevertheless, there was approximately 40% more phospholipid in cells grown at 7,500 ft/c than in cells grown with 100 ft/c; the phospholipid composition of the cells was similar under both conditions of growth. These observations lead us to suggest that the organization and perhaps localization of the phospholipids in Chromatium may be dependent on the light intensity supplied during growth.

Isolation and partial characterization of a major inositol-containing lipid in baker's yeast, mannosyl-diinositol, diphosphoryl-ceramide

A polar lipid containing about 20 per cent of the lipid soluble inositol has been purified from cells of Saccharomyces cerevisiae. This compound labeled with (3)H-inositol, (32)P(i), or (14)C glucose was isolated from aqueous pyridine extracts by means of paper chromatography. Unlabeled compound was obtained by a differential solubility scheme. Analytical and degradation studies suggest that this compound can be formulated as a mannosyl-diinositol, diphosphoryl-ceramide. It can be converted by treatment with base or acid into a mannosylmonoinositol phosphoryl-ceramide, a composition which relates it to the basic structure of the phytoglycolipids.

Separation and identification of the polar lipids of Chromatium strain D

The polar lipids of the autotrophically grown, obligately anaerobic, photosynthetic bacterium Chromatium strain D were separated by paper chromatography. Four major phospholipids were identified: lysophosphatidylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. In addition, three glycolipids were observed and characterized, namely, monoglucosyldiglyceride, which is found in other biological systems, and (mannosyl, glucosyl)-diglyceride and (dimannosyl, glucosyl)-diglyceride, which heretofore have not been observed in nature.