Tumor-reactive IgE antibodies in plasma of patients with gastrointestinal carcinomas

A total of 208 plasma samples from 115 patients with gastrointestinal carcinomas and nine patients with other intestinal disease were examined for the presence of IgE tumor antibodies by a solid-phase radioimmunoassay. Approximately one-third of the patients gave significant reactions with gastrointestinal carcinoma extracts compared with normal tissue extracts. Absorption with tumor and normal tissue extracts, with type AB human red cells, and with CEA indicated tumor specificity in some of the samples so examined. None of the 50 serum samples tested from normal blood donors contained tumor-specific IgE. IgE tumor antibodies decreased or completely disappeared in the majority of patients 8-13 days after surgical treatment.     

Evidence for the laryngeal source of ultrasonic and audible cries of rodents

The audible cries of three species of young myomorph rodents were found to be emitted through the nose and the mouth, buccal and nasal cavity resonances being involved in the production of the formant structures of the emitted cries. Ultrasonic cries were found to be emitted mainly through the mouth, with no evidence for the involvement of cavity resonances. Nerve sectioning experiments on adult and young rats implicated the larynx as the source of both their audible and their ultrasonic cries. However, consideration of the considerable differences in physical structure between the typically "vocal" audible cries and the ultrasonic cries, as well as other differences noted in the experimental conditions here and elsewhere, leads to the conclusion that the rodent larynx may operate in two quite different sound production modes.     

Interactions between Sympathomimetic Amines and Antidepressant Agents in Man

Intravenous infusions of phenylephrine, noradrenaline, adrenaline, and isoprenaline were given to healthy human volunteers after five to seven days on phenelzine, tranylcypromine, or imipramine, and cardiovascular responses were compared with those observed under control conditions. With monoamine oxidase inhibitors there was a 2-2½ fold potentiation of the pressor effect of phenylephrine, but no clinically significant potentiation of cardiovascular effects of noradrenaline, adrenaline, or isoprenaline. With imipramine there was potentiation of the pressor effects of phenylephrine (2-3 fold), noradrenaline (4-8 fold), and adrenaline (2-4 fold); there were dysrhythmias during adrenaline infusions, but no noticeable or consistent changes in response to isoprenaline.Noradrenaline and adrenaline in amounts contained in local anaesthetics used in dentistry are not likely to be significantly potentiated in otherwise healthy patients receiving monoamine oxidase inhibitors. Hazardous potentiation of their cardiovascular effects might occur in patients receiving tricyclic antidepressants.Our observations do not indicate that the hazards associated with isoprenaline inhalation by bronchial asthmatics would be increased by coincident therapy with a monoamine oxidase inhibitor or tricyclic antidepressant.     

Factors Affecting Virulence of Shigella flexneri: Defective Methionine Synthesis in an Escherichia coli-Shigella Hybrid

An Escherichia coli-Shigella flexneri hybrid of intermediate virulence was studied to determine whether its shorter survival in host cells might be due to a metabolic defect. Investigation of its growth in minimal glucose medium showed that the hybrid, like its E. coli parent, had a longer lag phase and a slower growth rate than its virulent Shigella parent. Methionine was found to increase the growth rate of the hybrid. The Shigella parent of the hybrid can synthesize methionine normally, but the E. coli parent has a point mutation in its metA gene. Since it synthesizes enough methionine to grow slowly, it is postulated that the hybrid strain has a hybrid metA gene, that is, a gene composed partly of deoxyribonucleic acid (DNA) from E. coli, with the balance of the DNA from S. flexneri. Phage P1-mediated transduction, with the metA(-)E. coli parent as recipient and the Shigella parent as donor, yielded a few transductants that responded to methionine in the same way the hybrid did. Many more transductants of the hybrid type were produced when the hybrid strain was used as a donor. It is suggested that this poorly functioning gene acts synergistically with the hybrid strain's relaxed synthesis of ribonucleic acid to prevent its survival in the host.     

Escherichia coli Mutant with Elevated Nicotinamide Adenine Dinucleotide Phosphate (Reduced) Oxidase Activity

A slow-growing mutant of Escherichia coli with greatly elevated nicotinamide adenine dinucleotide phosphate (reduced; NADPH) oxidase activity has been isolated. The oxidase activity of the wild-type organism, normally low at pH 7.5, was increased when the assay was performed at pH 6.0. Sucrose density gradients of sonic extracts of the mutant and wild-type strains revealed several peaks of NADPH oxidase activity at pH 6.0. The parent organism had a peak of activity of high molecular weight which was absent from the mutant. The mutant strain had an activator capable of increasing the activity of all wild-type density gradient peaks, especially the one of high molecular weight. The activator was either missing or masked in the wild type. Agar gel electrophoresis of the extracts uncovered a rapidly moving band from the wild type, missing from the mutant; the material in this band had weak NADPH-diaphorase activity and strongly inhibited the activity of the mutant NADPH oxidase. It was concluded that, in wild-type E. coli, NADPH oxidase activity is regulated by a proper balance of an activator and an inhibitor. The absence of the inhibitor, as in the mutant, or the inactivation of the inhibitor at acid pH levels, results in a high level of NADPH oxidase activity. The relation of high NADPH oxidase levels and subsequent decrease of the NADPH pool to the decrease in growth rate is considered.     

Stimulation of [3H]Dopamine Release by Nicotine in Rat Nucleus Accumbens

Abstract: The mesolimbic system of the brain has been shown to be involved in the reward properties of a number of agents. It is possible that release of monoamines by nicotine in this brain area could be related to the pleasurable aspects related to cigarette smoking. In this investigation, the effect of nicotine on the release of [³H]dopamine in the nucleus accumbens of the rat was studied. It was shown that nicotine produced a concentration-dependent increase in [³H]dopamine release at concentrations of 0.1 μ M and above. The increase in release was found to be almost completely calcium dependent. The nicotine-induced release was only partially blocked by the nicotinic antagonists hexamethonium and d -tubocurarine. A number of cholinergic agonists, as well as other compounds, were tested for their capacity to mimic the effect of nicotine. At equimolar concentrations there was, at most, only 50% of the activity of nicotine. The results of this study demonstrate that nicotine stimulates the release of dopamine in the nucleus accumbens at concentrations similar to those in the blood of cigarette smokers. This suggests that the release of mono-amines in specific nuclei of the mesolimbic system may be an important determinant of the desire to smoke cigarettes.     

Glyphosate-Degrading Microorganisms from Industrial Activated Sludge

A plating medium was developed to isolate N-phosphonomethylglycine (glyphosate)-degrading microorganisms, with glyphosate as the sole phosphorus source. Two industrial biosystems treating glyphosate wastes contained elevated microbial counts on the medium. One purified isolate metabolized glyphosate to aminomethylphosphonic acid, mineralizing this accumulating intermediate during log growth. This microorganism has been identified as a Flavobacterium species.