The effect of alcohol inhalation on the cardiovascular state of the rat

Rats were exposed to alcohol vapors by an inhalation technique and blood pressure and its reactivity and platelet aggregation were measured. Acute exposure to alcohol levels which produced moderate blood alcohol concentration (BAC) was associated with increased vascular production of prostacyclin (PGI2) and plasma catecholamines, whereas platelet production of thromboxane (TXA2) decreased. Blood pressure is elevated in these animals, however, the platelet aggregating and pressor effects of noradrenaline (NE) were decreased. Chronic exposure to high BAC is associated with a dramatic reduction in vascular and platelet prostaglandin (PG) production and a marked increase in plasma catecholamine levels. Platelet aggregation decreased in these animals, however, the pressor effect of TXA2 and NE was significantly increased. The fatty acid precursors to PG were reduced by 50% in the lipid extracts of these preparations. These findings suggest that alterations in fatty acid metabolism may lead to a functional deficiency in PG production from dependent rats. Qualitative differences may exist between acute and chronic exposure with respect to the cardiovascular state. Locally produced PG and circulating catecholamines may mediate alcohol-induced alterations in vascular smooth muscle tone and platelet aggregation.

Polyunsaturated fatty acids and ethanol

Ethanol exposure leads to a loss in membrane polyunsaturated fatty acids (PUFA). It is proposed that polyunsaturated species of phospholipids are not randomly distributed, but are concentrated in the cytosolic leaflets of the plasma membrane and are preferentially associated with membrane proteins. These lipids affect the physical state of environments surrounding membrane proteins and thereby serve to regulate many cellular functions. Disruption of these environments may occur even when a small percentage of total polyunsaturates is lost due to ethanol exposure. One possible mechanism of ethanol-induced polyunsaturate loss may be activation of a phospholipase A2 enzyme which is selective for these species of phospholipids. Fatty acids released would stimulate the production of prostaglandins and/or leukotrienes. Similarly, the released docosahexaenoate can be metabolized by rat brain to leukotriene-like compounds which are biologically active in smooth muscle systems. This metabolism is stimulated by ethanol in human platelets, in vitro.

GC/MS assay of prostaglandins in cerebrospinal fluid from humans and monkeys

The objective of this project has been to develop a sensitive and specific assay for prostaglandins in human cerebrospinal fluid (CSF) from patients with alcoholism and appropriate controls using gas chromatography/mass spectrometry. This study was initiated because numerous literature reports strongly suggest that a relationship exists between ethanol's central nervous system effects and the central production of prostaglandins. In both human and animal studies, administration of prostaglandin synthesis inhibitors prior to administration of ethanol attenuated central nervous system effects of ethanol. Samples from alcoholics after a three week period of abstinence and normals contained none of the measured prostaglandins (PGE2, PGE1, PGF1a, PGF2a, 6-keto-PGF1a) at a concentration more than twice the limit of quantification (3 pg/mL CSF). Comparison of GC/MS and radioimmunoassay methods provided further validation for these results. Literature reports of much higher levels of prostaglandins in normal controls, i.e., tens to hundreds of pg/mL CSF, appear to be incorrect. Examination of monkey CSF provided a positive control, since several of the prostaglandins were easily quantifiable in these samples.

A new technique for lipid analysis using liquid chromatography/mass spectrometry

It has been previously reported that ethanol alters the level of polyunsaturated fatty acids, and this may be related to alteration of membrane physical properties. Therefore, developing a technique to efficiently analyze lipid molecular species is of value for alcohol research. A new technique which can provide detailed structural information for most major lipid classes has been developed in our laboratory using thermospray liquid chromatography/mass spectrometry (LC/MS). In this technique, on-line LC separation is achieved with a conventional flow rate and the LC effluent is carried into the mass spectrometer via a heated capillary where it is vaporized and ionized. The results thus obtained for the major lipid classes including fast separation methods and quantitative aspects will be presented.

Needle aspiration cytologic diagnosis of metastatic malignant melanoma of unknown primary origin: report of a case and review of the literature

A rare case of metastatic malignant melanoma of unknown primary origin in a 49-year-old woman is reported. The swelling, localized in the right inguinal region, was partially immovable and associated with progressively increasing pain. Initial diagnosis was set by needle aspiration cytology and was confirmed postoperatively by histologic examination of a surgical specimen. Cytomorphologic features of metastatic malignant melanomas are described and the difficulties of identification discussed. A brief review of the literature is also made, and the rarity of the case and the value of cytologic diagnosis are emphasized.

Plasma adenosine levels: measurement in humans and relationship to the anxiogenic effects of caffeine

The effects of caffeine on plasma adenosine were examined in eight healthy normal volunteers. Subjects were randomly administered on 4 separate days, in a double-blind fashion, either placebo or three different doses of caffeine (240, 480, and 720 mg). Adenosine concentrations, measured by high performance liquid chromatography, were in the micromolar range when samples were drawn into tubes containing dipyridamole to prevent adenosine reuptake by red blood cells. Plasma adenosine levels did not change after caffeine administration. The effects of caffeine on anxiety were related to changes in plasma caffeine but not plasma adenosine levels. The potential interest of caffeine as a chemical model of anxiety is discussed.

Determination of eicosanoids, phospholipids and related compounds by thermospray liquid chromatography-mass spectrometry

Thermospray mass spectrometry has proven to be a useful technique for analyzing various biological compounds including eicosanoids and phospholipids. Molecular ions as well as fragment ions which reveal useful structural information are produced for underivatized eicosanoids and phospholipids using filament-off or filament-on thermospray mass spectrometry, respectively. In conjunction with on-line chromatographic separation, complex mixtures of biological samples can be rapidly analyzed with great reliability. Data will be presented concerning the analysis of prostaglandins, other eicosanoids and molecular species of phospholipids as well as the application of these methodologies to complex biological samples.

The effect of chronic alcohol inhalation on blood pressure and the pressor response to noradrenaline and the thromboxane-mimic U46619

Rats were exposed to alcohol vapor for 6 days and the mean blood ethanol concentration (BEC) was obtained for each subject. Blood pressure and its reactivity to noradrenaline and a thromboxane-mimic U46619 were directly measured on day 6 via a catheter implanted in the tail artery of normal and ethanol-treated animals. The mean BEC for each subject correlated with mean arterial blood pressure (MAP); an increase in BEC was associated with a decrease in MAP (p less than 0.02). The mean MAP of subjects with BEC less than 168 mg% was 8% higher than normal (not significant), whereas, the mean MAP of subjects with BEC greater than 182 mg% decreased 27 +/- 4% (p less than 0.01). Conversely, the pressor response to U46619 was markedly enhanced (p less than 0.005) in rats with mean BEC greater than 182 mg% at all doses investigated (12.5-3200 ng per rat). Increases in the pressor response to noradrenaline in ethanol-treated rats were significant only when maximally stimulated by 400 and 800 ng doses (p less than 0.03). A 3-fold increase in sensitivity for U46619 was seen in subjects with high mean BEC, however, sensitivity for noradrenaline did not significantly change. Vasoreactivity was not effected in rats with mean BEC less than 168 mg%. These data demonstrate that a moderate mean BEC for 6 days induces a tendency towards a mild hypertension, whereas, high mean BEC induces marked hypotension which is associated with hyperreactivity. Long-term exposure to high blood ethanol concentrations may predispose the alcohol-dependent rats to hypertensive disease and vasospastic disorders, at least partially, as a result of enhanced sensitivity to prostaglandins such as thromboxane.

Characterization of an automated apparatus for precise control of inhalation chamber ethanol vapor and blood ethanol concentrations

Inhalation chambers with a monitoring and control apparatus for ethanol vapor exposure of small animals were constructed. A thermal conductivity detector was employed for continuous measurement of inhalation chamber ethanol vapor concentration. The concentration was maintained within a very narrow range (+/- 1 mg/liter) by incorporating into the design a feedback loop which controls the ethanol pump. As expected, the blood ethanol concentrations (BEC) of male Sprague-Dawley rats were positively and linearly correlated to the chamber ethanol concentration. When rats were exposed for 24 hr to a chamber ethanol concentration of 17, 25, or 32 mg/liter, correspondingly low, moderate, or high mean blood ethanol levels were obtained. When a large population of this strain of rats (n = 121) was exposed to a constant ethanol vapor concentration for 14 days (25 mg/liter) considerable interindividual variation in blood levels occurred. There was also individual variation over time in the BEC of animals monitored. The mean +/- SD BEC was 189 +/- 90 mg/100 ml for this population and a gaussian-like distribution was obtained with regard to BEC. Behavior characteristic of alcohol withdrawal was observed in rats with BEC greater than 120 mg/100 ml after 3.5, 7, or 14 days of exposure. This apparatus and inhalation paradigm make possible the precise control of chamber ethanol concentration which markedly enhances control over both intra- and intersubject fluctuation in blood ethanol levels during alcohol exposure and the comprehensive examination of relationships between a wide range of blood ethanol concentrations and their physiological and biochemical effects.

Exfoliation of the beta-adrenergic receptor and the regulatory components of adenylate cyclase by cultured rat glioma C6 cells

Cultured rat glioma C6 cells exfoliate membrane vesicles which have been termed 'exosomes' into the culture medium. The exosomes contained both stimulatory and inhibitory GTP-binding components of adenylate cyclase (the stimulatory, Gs, and the inhibitory, Gi, regulatory components) and beta-adrenergic receptors but were devoid of adenylate cyclase activity. It was therefore apparent that the catalytic component of adenylate cyclase was either not exfoliated or was inactivated during the exfoliation process. The presence of Gs or Gi in the exosomes was detected by ADP ribosylation using [alpha-32P]NAD in the presence of cholera or pertussis toxins, respectively. The exosomal concentration of each of the two components was estimated to be about one fifth of that of the cell membrane when expressed on a per mg protein basis. Exosomal Gs was almost as active as the membrane-derived Gs in its ability to reconstitute NaF- and guanine nucleotide-stimulated adenylate cyclase activity in membranes of S49 cyc- cells, which lack a functional Gs. The ability of exosomal Gs to reconstitute isoproterenol-stimulated activity, however, was much lower than that of membrane Gs. The density of beta-adrenergic receptors in the exosomes was much less than that found in the membranes. Although the exosomal receptors bound the antagonist iodocyanopindolol with the same affinity as receptors from the cell membrane, the affinity for the agonist isoproterenol was 13- to 18-fold lower in the exosomes. In addition, this affinity was not modulated by GTP in the exosomes. Thus, exfoliated beta-adrenergic receptors seem to be impaired in their ability to couple to and activate Gs. This was directly tested by coupling the receptors to a foreign adenylate cyclase using membrane fusion. The fusates were then assayed for agonist-stimulated activity. While significant stimulation of the acceptor adenylate cyclase was obtained using C6 membrane receptors, the exosomal receptors were completely inactive. Thus during exfoliation, there appear to be changes in the components of the beta-adrenergic-sensitive adenylate cyclase that results in a nonfunctional system in the exosomes.

Effects of acute and chronic ethanol exposure on the response of rat aorta to a thromboxane mimic, U46619

The spasmogenic properties of a stable thromboxane mimic, U46619, were determined in the isolated rat aorta after 1, 4, 8, or 12 hr of acute ethanol exposure in vitro or after 12 days of chronic exposure by inhalation. Acute ethanol exposure (87-822 mM) increased the baseline tension of aortic rings in a concentration-dependent manner. Moderate concentrations of ethanol (11 and 43 mM) decreased the maximum tensile response of rat aortic rings to U46619 after 8 and 4 hr of exposure, respectively. In contrast, higher ethanol concentrations (87 and 411 mM) did not significantly effect the maximum tensile response to U46619. Ethanol at 822 mM completely inhibited the response to U46619 and this inhibition could be 85% reversed after removal of ethanol. The inhibitory effect of 1.64 M ethanol was irreversible. Sensitivity to U46619 was inversely related to the ethanol concentration (greater than or equal to 43 mM) and incubation time. Similarly, chronic exposure to moderate blood ethanol levels (92-198 mg/100 ml) for 12 days decreased the maximum tensile response whereas high levels did not effect aortic contractility in vitro. Sensitivity of aorta from rats with mean blood ethanol levels greater than or equal to 92 mg/100 ml decreased at least one order of magnitude. The results suggest that the effect of physiologically tolerable ethanol concentrations on the amplitude of the tensile response to U46619 is biphasic both during acute exposure in vitro or following a chronic exposure period in vivo and the inhibitory effect on sensitivity for U46619 is both concentration- and time-dependent in the rat aorta preparation.

Extraskeletal Ewing's sarcoma: first case report in Greece

The first case of soft tissue Ewing's sarcoma in Greece is presented. The tumour was a circumscribed large mass at the right calf, was radically excised and histologically proved to be small cell malignant neoplasm, performing the characteristic structural and cytological pattern of Ewing's sarcoma. Systematic clinical and radiological examination was negative. Operation was followed by local radiotherapy and systematic chemotherapy and the patient remains disease-free and clinically in perfect health eight months after the operation. The case is presented with special reference to its histological appearance and its treatment.

Synaptic effects of the synthetic pyrethroid resmethrin in rat brain in vitro

Resmethrin (30 microM) induced release of transmitters was not affected by manipulation of the Na+ current with either choline or tetrodotoxin agents which readily reversed the effects of veratridine, deltamethrin and cypermethrin. Resmethrin (I50: 2.2 microM) inhibited the ATP dependent uptake of Ca2+ but deltamethrin and cypermethrin were much less effective. Resmethrin also displaced Ca2+ from crude synaptosomal membranes. The release promoting effects of resmethrin in rat brain in vitro are better explained by its effects on Ca2+ rather than through a specific effect on the Na+ channel. In contrast, the effects of deltamethrin and cypermethrin promote transmitter release by a Na+ dependent process.

Effect of ethanol on prostacyclin and thromboxane A2 synthesis in rat aortic rings in vitro

Spontaneous 6-keto-PGF1 alpha and TXB2 levels in isolated rat aortic rings increased in a concentration dependent manner after a 0.5 hour incubation with moderate or high ethanol concentrations (11 mM to 218 mM). After a 1 hour incubation with moderate concentrations of ethanol less than or equal to 22 mM) spontaneous prostaglandin (PG) production did not increase although high concentrations (87 mM and 218 mM) increased both 6-keto-PGF1 alpha and TXB2 levels. Similarly, in the presence of 40 microM Na-arachidonate, high ethanol concentrations increased PG production after 0.5 and 1 hour incubation. In addition, either a 4 or an 8 hour exposure to high ethanol concentrations increased spontaneous PG production. A moderate concentration of ethanol (22 mM) increased the 6-keto-PGF1 alpha/TXB2 ratio whereas high levels (greater than or equal to 87 mM) depressed the ratio after 0.5 and 1 hour exposure. This effect was short-lived since after 4 or 8 hours incubation with high ethanol concentrations the 6-keto-PGF1 alpha/TXB2 ratio was markedly increased. The alcohol-induced changes in both spontaneous and arachidonate-stimulated PG levels were concentration dependent and related to the incubation time. Furthermore, these data suggest that there may be unbalanced production of PGI2 and thromboxane A2 in vascular tissue exposed to alcohol.

Alteration in the membrane fatty acid composition of human lymphocytes and cultured transformed cells induced by interferon

The effects of interferon (IFN) treatment on the lipid composition of human peripheral blood lymphocytes or transformed cell line cells were investigated. The major phospholipid classes of lymphocytes as analyzed by 2-dimensional TLC and quantified by phosphorous content were phosphatidylcholine (PC, 43%) and phosphatidylethanolamine (PE, 28%), along with phosphatidylserine (9%) and phosphatidylinositol (8%). The membrane-impermeant reagent, trinitrobenzenesulfonate was used to covalently label cell surface PE. Fatty acid (FA) composition, determined by gas-liquid chromatography, showed a distinct pattern in each lipid class, with a predominance of 16 and 18 carbon fatty acids (FA) in PC and PE respectively. Arachidonic acid (20:4) and, to a lesser extent, docosahexanoic acid (22:6) were predominant in PE. The degree of unsaturation in each class, expressed as the ratio between unsaturated and saturated FA (U/S), was higher in PE (1.72) than in derivatized trinitrophenyl cell surface PE (TNP-PE, 0.57) or PC (0.64). Treatment with IFN resulted in an increased U/S ratio in cell surface PE (1.10) but not in other PE species (1.46). A small increase in unsaturation (0.88) was also observed in PC. Most of the increase in TNP-PE U/S was accounted for by an increase in 20:4 and a concomitant decrease in 18:0. These alterations were observed in the absence of quantitative change in the principal phospholipid classes or in the FA composition of the total lipid extract. In K562, a transformed cell line with characteristics of the erythromyeloid lineage, PE was found to be the most saturated lipid class with a predominance of 18:0. In PC, 16:0 was most abundant. Among unsaturated FA, 18:1 predominated in all lipid classes studied. Treatment with natural IFN alpha for 30 hr generally resulted in a decrease in saturated FA and an increase in unsaturated FA, which was most marked in PE. The U/S ratio in PE was highest in K562 cells during the time of maximal cell proliferation as assessed by tritiated thymidine incorporation. TNP-PE simultaneously decreased. Daudi cells, a B-lymphoblastoid cell line, demonstrated changes in FA composition of lipids with decreased saturated and monoenoic FA after IFN treatment, whereas DIF3 (a clone selected for lack of sensitivity to IFN) showed no change. These studies document changes in membrane FA composition of lymphocytes treated with IFN and correlate IFN-induced changes in transformed cell line FA with effects on proliferation. They further show the existence of a transverse molecular species asymmetry of PE in the plasma membrane of these cells which is altered after IFN treatment.

Malignant mesothelioma of testicular tunica

A case of malignant mesothelioma of testicular tunica in a 26 year old male is presented. Operation was followed by local radiotherapy. The patient remains disease free one year after initial diagnosis.

Microfibrillar protein and phospholipid in granular corneal dystrophy

Keratoplasty specimens from eight patients with granular corneal dystrophy (GCD) and age-matched control subjects were examined by combinations of immunohistological stains, transmission electron microscopy (TEM), and sodium dodecyl sulfate gel electrophoresis. Fresh frozen sections from corneas with GCD stained positively with antibodies to microfibrillar protein by immunofluorescence. Routine TEM disclosed that the granules had central electron-dense areas partially surrounded by 9- to 10-nm tubular microfibrils. Material eluted from corneas with GCD showed denser peptide bands at 65 and 110 kilo than in normal corneas. Stains were negative for elastin, amyloid, neutral lipids, cholesterol, and glycosaminoglycan. Luxol fast blue MBSN stain was strongly positive in the granules in all cases examined. Immunofluorescent stains were negative with antibodies to plasma fibronectin (cold insoluble globulin), laminin, collagens I to V, basement membrane proteoglycan, tropoelastin, and keratin. In two corneas with GCD an increased lipid content was found in every phospholipid class, although cholesterol content was unchanged. Alterations in the fatty acid profiles of phospholipids were also observed.

Mn2+-stimulated ATPase in rat brain

Divalent cation ATPases were prepared from rat brain synaptic vesicles, synaptosomal plasma membranes, and plasma membranes from the brain stem and sciatic nerve and tested for optimal stimulation by Mn2+, Mg2+, or Ca2+. ATPase in the synaptic vesicle subfraction was optimally stimulated by Mn2+. All plasma membrane preparations were optimally stimulated by Mg2+. Separate Mn2+ and Mg2+ ATPases could not be distinguished by either chemical inactivation or substrate preference criteria. Mn2+ stimulated ATPase in the micromolar range and it is suggested that Mn2+ interaction with ATPase may be of physiological and/or toxicological importance by being related to the cellular metabolism of this element.

Ecto-5'-nucleotidase regeneration after chemical modification of the plasma membrane

Treatment of the C6 glioblastoma cell with trinitrobenzenesulfonic acid (TNBS) resulted in the selective inactivation of ecto-5'-nucleotidase under conditions which maintained cell viability. Cells respond to ecto-enzyme inactivation by replacing 80% of lost activity within 24 hrs. A lag time of 4-6 hrs before ecto-5'-nucleotidase replacement began and its complete blockage by cycloheximide indicated that the source of replaced enzyme was de novo synthesis and not an intracellular pool. Release of 5'-nucleotidase activity into culture medium in the form of membraneous vesicles slowed during the active recovery period and then steadily increased with time as the plasma membrane enzyme level approached normal. TNBS did not exert a direct inhibitory action upon the exfoliative process as release of vesicular GM1 and protein were little affected. Decrease in exfoliated 5'-nucleotidase activity may be due to a selective conservation of the enzyme in the exfoliative process.