The roles of ethanol and of acid in the production of gastric mucosal erosions in rats

This study was undertaken to differentiate between the morphological changes produced in chambered rat gastric mucosae by 40% ethanol and by 50 mM HCl. 40% ethanol produced both focal mucosal hyperemia and widespread exfoliation of the surface epithelium. Massive release of mucus accompanied both events. In the absence of acid the released mucus was stabilized by a network of fibrin, and epithelial continuity was re-established over non-hyperemic regions by migration of epithelial (and parietal) cells from the gastric pits. Hemorrhagic erosions occurred only in the presence of acid, but were limited to the hyperemic regions. Acid had the following effects: (1) platelet thrombi were destroyed, thus promoting hemorrhage; (2) destruction of the fibrin network by acid caused dissipation of the adherent mucous coat; (3) vulnerable cells which had previously shown only ischemic damage were irreversibly damaged by acid; (4) exposed basal lamina was destroyed, thus removing the substratum necessary for orderly epithelial re-establishment.     

Cross-reactivity between human and murine lymphocyte antigens

The anti-H-2 alloantiserum D-32 [(BlO.A(2R) × C3H.SW) anti-C3H] is cytolytic to human lymphocytes. Fab₂ blocking assays, indirect immunoprecipitation and sequential immunoprecipitation experiments showed that the anti-H-2 alloantiserum D-32 recognizes antigenic determinants which are expressed on the heavy chain of subpopulations of HLA-A, B antigens. These determinants are different from those defining the serological polymorphism of the HLA-A, B, C system, are the same as or spatially close to those recognized by the anti-HLA-A, B monoclonal antibody Q6/64 and are expressed on rabbit, rat or guinea pig lymphocytes.     

Modelling the rate of transfer of uranyl ions onto microbial cells

It has been observed that microbial cells can adsorb uranium ions from dilute aqueous solutions. Data collected from such experiments can be used to estimate correlative mass transfer coefficients. Physical observations bear out several inadequacies, however, of using an adsorption mass transfer model with a constant transfer coefficient relating the rate of transfer to the concentration gradient. By itself, the mass transfer model contains no provision to include (1) the initial transient, (2) the curvature in the later time rate curve, and (3) the non-linear curve relating initial levels of uranium concentration in solution to final residual uranium concentration for a set of batch experiments. It is found that a better match to observed data can be achieved by utilizing an intermediate state adsorption model analogous to a kinetic model based on an enzyme - substrate coupling scheme.     

Oxygen consumption during the fenton-type reaction between hydrogen peroxide and a ferrous-chelate (Fe2+-DTPA)

The Fenton-type reaction between ferrous diethylenetriamine pentaacetic acid (Fe²⁺-DTPA, 50–200 μM) and H₂O₂ (20–1000 μM) in phosphate buffer at pH 7.0 results in consumption of dissolved oxygen. This observation differs from many prior reports that oxygen is liberated when more concentrated solutions of H₂O₂ are decomposed by iron salts. The rate and total quantity of oxygen consumed were dependent upon the concentrations of ferrous chelate, H₂O₂, and excess DTPA. Evidence is provided that both the ferrous-DTPA chelate and free DTPA can participate in the oxygen-consuming reactions. Oxygen was also consumed during the Fenton reaction between ferrous ions and H₂O₂ when DTPA and phosphate buffer were omitted. Under these conditions, oxygen evolution was observed at higher H₂O₂ concentrations (e.g., 400 μM). The consumption of oxygen during the Fenton-type reaction of an iron chelate at neutral pH may be relavant to events that take place in biologic systems.     

Determination of indoles and catechols in rat brain and pineal using liquid chromatography with fluorometric and amperometric detection

Tryptophan, serotonin, 5-hydroxyindoleacetic acid, and homovanillic acid were determined in rat brain by the direct injection of a centrifuged tissue homogenate into a liquid chromatographic—fluorometric/amperometric system. The above indoles, along with melatonin, were also determined in single rat pineal glands. The utility of the system in determining several additional catechols and indoles in brain was examined.     

The hypothalamo-choroidal tract

Summary Light and electron microscopic examination of choroid plexuses from lateral ventricles of water-deprived and subcutaneously or intravenously vasopressin administered rats reveal morphologic changes typical for vasopressin responsive fluid transporting epithelia during hormonal stimulation. Ultrastructural changes noted in both dehydrated and vasopressin treated animals included: the frequent occurrence of choroidal dark cells, dilatation of the lateral and basal intercellular spaces, increased vacuolization of the apical cytoplasm, and a change in microvillar conformation from the normal clavate type to those with a filiform shape. On the basis of the ultrastructural changes observed it is proposed that the choroid plexus be regarded as a target tissue for vasopressin. These findings indicated that a vasopressinmediated transchoroidal cerebrospinal fluid absorption capability exists.Supported by U.S.P.H.S. Grant HD-08867This work submitted as partial requirement for the Master of Science degree in the Department of Anatomy, Colorado State University     

Anomalous cellular proliferation in vitro associated with Huntington's disease

Summary Detailed growth analyses of cultured skin fibroblasts from two patients with Huntington's Disease (HD) were compared with those from controls matched for age and sex. In contrast to control cells, HD fibroblasts plated more efficiently at the low seeding densities used. Subsequent exponential growth of HD cultures was more stable towards routine trypsinisation than that of controls. However, the most striking feature of HD cultures was their ability to grow to significantly higher cell saturation densities. Experiments with trypsinised and untrypsinised cultures imply an inherent alteration in the HD cell membrane.     

The multiple forms of brain acetylcholinesterase

Summary Micro-polyacrylamide gradient electrophoresis followed by active staining is applied for the demonstration of the multiple forms of acetylcholinesterase. Among other advantages the very small samples that enable the analysis of well-defined brain material as well as the almost histochemical conditions of incubation enable its successful use in topochemical investigations of the multiple form pattern of brain acetylcholinesterase.The acetylcholinesterase of bovine nc. caudatus could be separated into 4 multiple forms and the pattern was analysed microdensitometrically. These forms differ in their molecular weight as well as well as in their degree of membrane binding. Increasing ionic strength (NaCl) is followed by changes in the pattern. This result is discussed as caused by aggregation of enzyme subunits.The research reported in this paper was supported by the Ministerium für Wissenschaft und Technik der DDR     

CITRATE AS THE PRECURSOR OF THE ACETYL MOIETY OF ACETYLCHOLINE

Abstract— Rat brain cortex slices were incubated with glucose labeled with either ³H or ¹⁴C in the 6-position. The ³H/¹⁴C ratios and the incorporation of radioactivity into lactate, citrate, malate and acetylcholine were determined. While the ³H/¹⁴C ratio of lactate was close to that of glucose, the ratios in the acetyl moiety of acetylcholine and the acetyl (C-4,5) portion of citrate decreased in a similar proportion. This was interpreted as indirect evidence for the participation of citrate as a precursor to the acetyl moiety of acetylcholine. Two inhibitors of the citrate cleavage pathway: n -butylmalonate, an inhibitor of citrate transport and (-)-hydroxycitrate, an inhibitor of ATP-citrate lyase were studied for their effect on acetylcholine synthesis. N -butylmalonate (10 mM) and (-)-hydroxycitrate (7.5 mM) led to a decrease in the per cent of ¹⁴C recovered as acetylcholine. In each instance the ³H/¹⁴C ratio in acetylcholine was higher in the presence of inhibitor while the corresponding ratios in lactate and citrate (C-4.5) remained unchanged. From the results, it is suggested that citrate is involved in the transport mechanism of acetyl units from its site of synthesis in mitochondria to the site of acetylcholine synthesis in the cytosol.