Ionic mechanisms of excitatory action of transmitter,exogenous acetylcholine,and serotonin on superior cervical ganglion neurons in rabbits

Ionic mechanisms of EPSP generation and depolarization induced by iontophoretic application of acetylcholine (ACh) and serotonin (5-hydroxytryptamine, 5-HT) — acetylcholine and serotonin potentials — were investigated in neurons of the isolated rabbit superior cervical ganglion by means of intracellular microelectrodes. The reversal potentials (E_r) for EPSP and the ACh-potential were –14.4±1.6 and –16.5±1.2 mV respectively, and they were about the same for the 5-HT potential. In some neurons (about one-third) much more negative values for E_r were obtained for EPSP and the ACh-potential by extrapolation, probably due to an increase in the resistance of their membrane during hyperpolarization. A decrease in the external sodium and potassium concentrations was shown to make E_r for EPSP and the ACh-potential more negative, whereas an increase in the external potassium concentration made it more positive than in normal solution; a change in the external chloride concentration did not alter E_r. It is suggested that the excitatory transmitter and exogenous ACh (and also, probably, 5-HT) share the same ionic mechanism of action of the membrane, which includes an increase in the permeability of the membrane to two ions — sodium and potassium — simultaneously.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 10, No. 6, pp. 637–644, November–December, 1978.     

Hume and the argument for biological design

There seems to be a widespread conviction — evidenced, for example, in the work of Mackie, Dawkins and Sober — that it is Darwinian rather than Humean considerations which deal the fatal logical blow to arguments for intelligent design. I argue that this conviction cannot be well-founded. If there are current logically decisive objections to design arguments, they must be Humean — for Darwinian considerations count not at all against design arguments based upon apparent cosmological fine-tuning. I argue, further, that there are good Humean reasons for atheists and agnostics to resist the suggestion that apparent design — apparent biological design and/or apparent cosmological fine-tuning — establishes (or even strongly supports) the hypothesis of intelligent design.     

Adjunctive strategies to enhance peripheral warming: Clinical techniques

This study investigates common successful strategies to increase peripheral temperature with biofeedback. Eighteen BCIA-certified therapists (average years of practice, 7.5) were interviewed by telephone for 30 to 45 minutes regarding successful peripheral warming strategies. The practitioners reported using multiple teaching strategies, either concurrently or sequentially. These responses were organized into an interrelated four-category model that consists of the following: (1) Attentional Category — shifting from active to passive attention; (2) General Arousal Category — shifting from hyper- to hypoarousal; (3) Proprioceptive/Kinesthetic Awareness Category — shifting from decreased to increased body awareness; (4) Self-Image/Self-Esteem Category — shifting from negative to positive self-image/self-esteem. These four categories and their corresponding techniques can be used to facilitate peripheral warming.We thank Jackie Myers for her helpful suggestions.     

Measurement of ion-induced noise in atmospheric counting chambers,and a novel chamber for its elimination

Atmospheric small-ion enhancement is widely employed in medical, physiological and horticultural research. Accurate measurements of both positive and negative ion concentrations are then essential, but in the face of the high ion ratios encountered — up to 10³ — the classical two-electrode counter is unable to measure the ion of low concentration. It is found that the reading is obliterated by noise.The phenomenon is demonstrated and the theory of counting chambers is extended to include it. A novel three-electrode chamber which is free from ion-induced noise is then designed and the Paper concludes with the test results obtained by its use.     

On the mechanism of anion uptake by plant roots

Summary The effect of the valence of the associated cation on Cl^–-uptake by excised barley roots grown in CaSO₄ has been studied at 26°, 6° and 2°C. The uptake of Cl^– relative to that of the associated cation was found to increase in the order: trivalent > divalent > monovalent. This was explained on the expected effect of the cation on the negative charge and potential of root surfaces. A lyotropic order was observed in case of monovalent cations, whereas divalent cations showed no such order. The order observed in Cl^–-uptake from chloride solutions of monovalent cations is associated with the ability of the absorbed cation to remove Ca and Mg from the roots. Li⁺ behaved similar to divalent cations in affecting the relative Cl^–-uptake from LiCl.As to the effect of temperature on the uptake of Cl^– and associated cation, it appears that Cl^– is not taken up to any great extent at 2°C whereas cations are still adsorbed at this low temperature. This has been explained on the assumption of the presence of negative adsorption spots on the root surface which can hold cations but not anions. It appears that Cl^–-uptake by roots requires the expenditure of energy to overcome repulsion arising from the negative surface.This work is supported by AEC contract AT (11-1) — 34 project 55.     

Light- and electron microscopic investigations on the median eminence of the pigeon after TSH and PTU treatment

Summary 1. The effects of TSH and PTU treatment with thyroid stimulating hormone and propylthiouracil on the structure of median eminence of the pigeon have been studied by light- and electron microscopy.2. By light microscopy it has been found that the aldehydefuchsin positive material of the external layers of the anterior median eminence differs functionally from that of the neural lobe.3. The light- and electron microscopic investigations revealed that the anterior and posterior median eminence differ both structurally and functionally. Specifically after the experimental interventions the considerable reaction can be observed only in the anterior median eminence.4. Electron microscopically it appears possible that the aldehyde-fuchsin positive material of the anterior median eminence may be associated with the 1200–1500 Å—size granules.5. The quantitative changes observed in the granular composition after the treatments show a close correlation with thyroid function, namely after treatment with thyroid stimulating hormone the relative quantity of the 1200–1500 Å—size granules increases markedly, while administration of propylthiouracil has the opposite effect and increases the relative quantity of the 1000 Å—size dense-core vesicles. They presumably may play a role in the control of TSH-secretion.Abbreviations TSH thyroide stimulating hormone - PTU propylthiouracil - ME median eminence - AME anterior median eminence - PME posterior median eminence - AF+ aldehyde-fuchsin positive - AF– aldehyde-fuchsin negative     

Inhibition in the fish olfactory bulb

Inhibition in the olfactory bulb of the carp was studied by recording potentials from secondary neurons intracellularly. Three types of inhibition — trace, early, and late — can arise in neurons of the olfactory bulb. Trace inhibition corresponds to hyperpolarization about 20 msec in duration, which is closely connected with the spike, but it is not after-hyperpolarization but an IPSP. Early and late inhibition correspond to IPSPs of different parameters. The first has a latency of 0–50 msec (relative to the spike) and a duration of 60–400 msec; the corresponding values for the second are 100–400 msec and 0.5–3 sec. The possible mechanisms of these types of inhibition are discussed.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 3, No. 6, pp. 650–656, November–December, 1971.     

Ultrastructure of segmentation mitoses in cleaving newt eggs after blocking of centrospheres by quinoline

In quinoline treated blastomeres of Triturus helveticus Raz. and Pleurodeles waltlii Michah., microtubules disappear and around the centrioles markedly enlarged dense bodies accompanied by striated bodies are accumulated, from prophase beyond metaphase. It is concluded that these bodies in untreated cells play a role in the formation of the spindle microtubules. — During metaphase the chromosome are smooth-surfaced and show a pronounced tendency to stickiness. During ana-telophase they become surrounded by nuclear membranes and form caryomeres. — Quinoline does not interfere with centriole replication, but prevents the separation if diplosomes that have been already formed, if it acts before that separation. — Some centrioles exhibit different degrees of ultrastructural disarrangement.     

ATP-activated ionic conductance in the somatic membrane of mammalian sensory ganglionic neurons

ATP receptors, activation of which leads to an increase in membrane conductance for monovalent cations and to the appearance of an inward ionic current at negative membrane potential values, have been found on the outer surface of the somatic membrane of sensory ganglionic neurons of rats and cats. The ATP-activated ionic channel is almost equally permeable for ions of the alkali metals and possesses marked permeability even for Tris and tetraethylammonium ions. Simultaneously with this, the channel demonstrates marked anomalous rectification. For the receptor to be activated, one ATP molecule must interact with it. Activation of the receptors is not connected with the use of energy of high-energy bonds. Affinity of the receptors for agonists is increased with a fall of membrane potential. Adenine nucleotides containing at least two phosphoric acid residues are agonists. The most active agonist is ATP. Adenosine monophosphate, adenosine, and puromycin competitively block these receptors. Pyrimidine nucleotides, and also purine nucleotides — guanosine triphosphate and inosine triphosphate — do not interact with ATP receptors. ATP-activated currents develop quickly and are then slowly desensitized. The desensitization time constant decreases with an increase in ATP concentration, to reach about 2 sec at a saturating concentration.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 16, No. 3, pp. 327–336, May–June, 1984.     

Residue screening for the β-agonists clenbuterol, salbutamol and cimaterol in urine using enzyme immunoassay and high-performance liquid chromatography

The antibody for enzyme immunoassay was raised against clenbuterol-diazo-BSA, and salbutamol-carboxymethyl ether-biocytin was used as a label. Procedural blanks from 500 negative urine samples were always <0.2 ppb salbutamol or <0.02 ppb clenbuterol equivalents, and a residue level of 1 ppb was detected with good reliability. After treatment of veal calves with anabolic dosages, residue levels in urine amounted to 10–200 ppb clenbuterol or salbutamol. β-Agonists were separated by high-performance liquid chromatography on LiChrospher RP-Select B columns, and acidic methanol—buffer or acetonitrile—buffer mobile phases. Combinations of high-performance liquid chromatography and enzyme immunoassay were used for confirmation.     

Mimosine Arrests the Cell Cycle after Cells Enter S-Phase

-Mimosine (β-N-[3-hydroxy-4-pyridone]-α-aminopropionic acid)—a rare amino acid derived fromMimosaandLeucaenaplants—arrests cells reversibly late during G1 phase or at the beginning of S-phase. If mimosine were to arrest cells immediately before S-phase, it would provide a superb tool for the investigation of the initiation of DNA synthesis. Therefore, we reexamined the point of action of mimosine. Mitotic HeLa cells were released into 200 μMmimosine and grown for 10 h to block them, before the cells were permeabilized and the amino acid removed by washing them thoroughly. On addition of the appropriate triphosphates, DNA synthesis—measured by the incorporation of [³²P]dTTP—began immediately; as it is known that such permeabilized cells cannot initiate DNA synthesis but can only resume elongating previously initiated chains, mimosine must arrest after DNA synthesis has begun. Moreover, cells grown in mimosine assembled functional replication factories—detected by immunolabeling after incorporation of biotin–dUTP—that were typical of those found early during S-phase. Disappointingly, it seems that mimosine—like aphidocolin—blocks only after cells enter S-phase.     

Disease in marine aquaculture

It has become almost a truism that success in intensive production of animals must be based in part on development of methods for disease diagnosis and control. Excellent progress has been made in methods of diagnosis for major pathogens of cultivated fish, crustacean and molluscan species. In many instances these have proved to be facultative pathogens, able to exert severe effects in populations of animals under other stresses (marginal physical or chemical conditions; overcrowding). The concept of stress management as a critical prophylactic measure is not new, but its significance is being demonstrated repeatedly. The particular relationship of water quality and facultative pathogens such asVibrio, Pseudomonas andAeromonas species has been especially apparent. Virus diseases of marine vertebrates and invertebrates — little known two decades ago — are now recognized to be of significance to aquaculture. Virus infections of oysters, clams, shrimps and crabs have been described, and mortalities have been attributed to them. Several virus diseases of fish have also been recognized as potential or actual problems in culture. In some instances, the pathogens seem to be latent in natural populations, and may be provoked into patency by stresses of artificial environments. One of the most promising approaches to disease prophylaxis is through immunization. Fish respond well to various vaccination procedures, and new non-stressing methods have been developed. Vibriosis — probably the most severe disease of ocean-reared salmon — has been controlled to a great extent through use of a polyvalent bacterin, which can be modified as new pathogenic strains are isolated. Prophylactic immunization for other bacterial diseases of cultivated fish has been attempted, especially in Japan, with some success. There is also some evidence that the larger crustaceans may be immunologically responsive, and that at least short-term protection may be afforded to cultured populations. Some progress has been made in marine disease control through chemical treatment in intensive culture systems, principally through application and modification of methods developed for freshwater aquaculture. Major constraints to use of chemicals are restrictions due to public health concerns about food contamination, and the negative effects of some chemicals on biological filters and on algal food production. There is a continuing need, however, for development of specific treatments for acute disease episodes — such as the nitrofurans, developed in Japan, which are effective for some bacterial diseases. The history of aquaculture — freshwater as well as marine — has been characterized by transfers and introductions of species to waters beyond their present ranges. The process continues, and carries with it the possibility of transfers of pathogens to native species and to the recipient culture environments. International groups are attempting to define codes of practice to govern such mass movements, but examples of introductions of real or potential pathogens already exist. The most recent and the most dramatic is the world wide transfer of a virus pathogen of penaeid shrimps. Earlier examples include the introduction of a protozoan pathogen of salmonids to the western hemisphere, and the introduction of a parasitic copepod from the Far East to the west coast of North America and to France. The conclusion is inevitable — diseases are substantial deterrents to aquaculture production. Diagnostic and control procedures are and will be important components of emerging aquaculture technology.     

Seasons of birth and marriage in two Chinese localities

Data from two rural Chinese settings suggest that an ecological variable — the reliability of food supply — may exert a more decisive influence on birth seasonality than time of marriage or attributes of temperature, rainfall, or workload. First births seem to be especially important for patterns of seasonality; comparison between villages suggests that a periodic but reliable source of food may encourage a seasonal distribution of first births, the effect of which might be to protect the mother and/or her newborn infant. It is the periodicity of first births that may give aggregate birth figures the appearance of seasonality.This paper is based on fieldwork conducted by Myron L. Cohen (Columbia) and myself and is part of a larger, continuing study of the social and economic attributes of a particular Chinese regional system. Fieldwork and initial data analysis were funded by the National Science Foundation with supplementary support for further data analysis provided by the Research Foundation of the City University of New York. A debt of gratitude is due the Institute of Ethnology, Academia Sinica (Taiwan) and the Joint Commission on Rural Reconstruction (Taiwan) for encouragement and sponsorship in the field. I am particularly grateful to my colleagues Carol R. and Melvin Ember, and Gregory Johnson for the generous statistical and critical assistance they provided during analysis of the data from Meinung. I am also indebted to Arthur Wolf (Stanford) and to Margery Wolf for suggestions and criticisms offered after reading an early version of the present paper.     

Sialic acid in colonic mucin: An evaluation of modified PAS reactions in single and combination histochemical procedures

Summary Two new histochemical procedures for detecting sulphated and non-sulphated sialomucin in colonic mucosa were assessed: the saponification—Alcian Blue pH 1—periodic acid—phenylhydrazine—Schiff method (KOH—AB pH 1—PAPS) and the mild periodic acid modification of this (KOH—AB pH 1—mPAS). Using normal colonic mucosa obtained from 11 non-cancer patients, the mPAS and PAPS techniques were tested for specificity and reproducibility for staining sialic acid, either alone or in combination with Alcian Blue. A spectrophotometric method was devised to quantify the uptake of both Schiff and Alcian Blue stain by sections. At low temperature and pH5.5, the mPAS procedure had improved specificity over the PAPS procedure, and after saponification it could be used to stainO-acetyl-substituted sialic acid. When used in combination with Alcian Blue at pH 1, however, underestimation of the sialic acid content occurred owing to interference between Alcian Blue and Schiff dyes. Interference was even greater with KOH—AB pH1—PAPS procedure for both sialic acid and sulphate components. We conclude that caution must be exercised in interpretation of the staining results obtained with these new combination methods and that more accurate information on the sialic acid and sulphate content of colonic mucin is obtained by staining serial sections with the mPAS technique and Alcian Blue pH 1 alone.     

On the proper use of sigma analysis in the study of flash-induced oxygen evolution

Analysis of oxygen yield by photosynthetic higher plants systems submitted to flash sequence using the so-called sigma method as proposed in Lavorel (1976), J Theor Biol 57: 171–185 has been recently criticized in this Journal by Meunier and Popovic (1989), Photosynth Res 22: 131–136. By properly applying the above method—in particular using Meunier and Popovic's own data—it is argued that the criticism is not justified.     

Absence of harmful effects of protracted negative air ionisation

The absence of harmful effects of protracted negative air ionisation was studied in 5 weather-sensitive women and 5 normal men chosen at random. Negative ions were generated by the Modulion of Amcor-Amron (Herzliya, Israel). The patients were exposed separately during 8 sleeping hours and 8 working hours to the apparatus at 1–2 m distance in a 4 × 4 m room, for 2 months. Thus they were exposed to a daily uptake of 1 × 10⁴ negative ions/cm³ for 16 h/day during 2 months. Urinary 17-KS, 17-OH, adrenaline and noradrenaline excretion was not affected by the negative ionisation. However serotonin, 5-HIAA, histamine and thyroxine excretion — if increased before — diminished by 50% on an average. There were no changes in body weight, blood pressure, pulse, respiratory rate, oral morning temperature, dynamometer grip strength, routine liver function tests, urinary pH, albumen, glucose, ketones, bilirubin, or occult blood, red and white blood count and ECG records. The EEG revealed the typical changes due to negative air ionisation: stabilising of frequency, increased amplitudes, spreading of brainwaves from the perceptive occipital area to the conceptive frontal area and synchronisation of both hemisphere tracings.     

Ecological consequences and ontogeny of seed heteromorphism

Seed heteromorphism represents the production of different kinds of seeds by a single individual. The morphological differentiation affects either the fruit — heterocarpy — or the seed sensu stricto — heterospermy. In this study the phylogenetic distribution of seed heteromorphism among different families and habitats is investigated for 218 plant species based on existing literature. The ecological consequences of seed heteromorphism are explored as well. Seed heteromorphism is most common in the Asteraceae and Chenopodiaceae, suggesting that these families have morphological characteristics favouring the appearance of seed heteromorphism and ecological features that maintain it. Using the distribution of seed heteromorphism within the genus Crepis, the relationship between seed heteromorphism and life cycle and habitats is examined. From this analysis it appears that heterocarpic species are often monocarpic. In contrast, the relationship between heterocarpy and habitats is not obvious. Finally, a synthesis is presented about the ontogeny of heteromorphism and some guidelines are proposed for future research on this topic.     

Fluorescence-displacement from the median eminence towards the arcuate nucleus at puberty

Summary The transition from infanthood to adulthood is characterized by a sequence of events which are not yet fylly understood. Hormonal changes influencing neuronal circuits in various hypothalamic area are —at least in part — held responsible. Using catecholamine fluorescence techniques in rats it has been found that a displacement of dopaminergic cells can be seen; the fluorescence activity shifting from the median eminence at day 20 after birth to the dorsolateral part of the arcuate nucleus around day 45 after birth, as is the case for catalase positive cells in these areas. It is concluded that the displacement of at least two populations of cells from the median eminence to the arcuate nucleus runs parallel to the onset of puberty. The relation of this shift in respect to the suprachiasmaticpreoptic control will be discussed.     

Bioanalysis of erythromycin 2'-ethylsuccinate in plasma using phase-system switching continuous-flow fast atom bombardment liquid chromatography—mass spectrometry

A specific method for the determination of erythromycin 2'-ethylsuccinate (EM-ES) in plasma is described. The method involves a liquid—liquid extraction procedure followed by the analysis of extracts using phase-system switching (PSS) continuous-flow fast atom bombardment (CF-FAB) liquid chromatography—mass spectrometry (LC—MS). In PSS EM-ES is enriched after analytical separation on a short trapping column, from which it is desorbed to the LC—MS interface. In this way, favourable mobile phases can be used for the LC separation and for the MS detection. Using the PSS approach a flow-rate reduction from 1.0 ml/min in the LC system to 15 μl/min going into the mass spectrometer was achieved without splitting. The determination limit for EM-ES was 0.1 μg/ml.     

Does any enzyme follow the Michaelis—Menten equation?

Summary A literature search has been conducted to see to what extent steady-state kinetics studies in the period 1965–1976 have revealed deviations from Michaelis—Menten kinetics. It was found that over 800 enzymes have been reported as giving complex curves for a variety of reasons and a group by group classification of all these enzymes has been carried out listing all the types of variations reported and the authors' explanations. In addition, for highly complex curves, we have determined the minimum degree of the rate equation. There were very few determined attempts to demonstrate adherence to the Michaelis—Menten equation over a wide variety of experimental conditions and substrate concentration and almost invariably detailed experimental work revealed unsuspected complexities. For these reasons, it is concluded that the assumption that most enzymes follow the Michaelis—Menten equation can not be supported by an appeal to the literature.