Microwave Staining of Intestinal Whole-mount Preparations with Cuprolinic Blue

Encouraged by the knowledge that microwaves have a beneficial effect on immunohistochemical reactions, the present study aimed to find out whether microwaves could improve the Cuprolinic Blue staining of enteric neurons as well as the actual method that has been developed for gastrointestinal whole-mount preparations. In addition to incorporating a microwave application in the method described by Holst and Powley (1995), some other modifications were made: two incubations before incubation in the staining solution and free-floating incubations. In the whole-mount preparations, most, if not all, enteric neurons were stained by Cuprolinic Blue. These neurons appeared as blue–green cells with non-reacting nuclei and neuronal processes. At higher magnification, the cytoplasm was characterized by a fine blue– green granulation, and the nucleolus in the nucleus appeared as a blue iridescent structure. Non-specific staining occurred in fibrocy tes and epithelial cells but, because of their location and appearance, they could easily be distinguished from neurons. The modified incubations and the incorporation of a microwave application into the conventional Cuprolinic Blue staining method turn the method into an easy-to-use one that seems to visualize most, if not all, enteric neurons in whole-mount preparations of the pig jejunum.     

Dietary fat intake and risk of stroke in male US healthcare professionals: 14 year prospective cohort study

Objective To examine the association between intake of total fat, specific types of fat, and cholesterol and risk of stroke in men.Design and setting Health professional follow up study with 14 year follow up.Participants 43 732 men aged 40-75 years who were free from cardiovascular diseases and diabetes in 1986.Main outcome measure Relative risk of ischaemic and haemorrhagic stroke according to intake of total fat, cholesterol, and specific types of fat.Results During the 14 year follow up 725 cases of stroke occurred, including 455 ischaemic strokes, 125 haemorrhagic stokes, and 145 strokes of unknown type. After adjustment for age, smoking, and other potential confounders, no evidence was found that the amount or type of dietary fat affects the risk of developing ischaemic or haemorrhagic stroke. Comparing the highest fifth of intake with the lowest fifth, the multivariate relative risk of ischaemic stroke was 0.91 (95% confidence interval 0.65 to 1.28; P for trend = 0.77) for total fat, 1.20 (0.84 to 1.70; P = 0.47) for animal fat, 1.07 (0.77 to 1.47; P = 0.66) for vegetable fat, 1.16 (0.81 to 1.65; P = 0.59) for saturated fat, 0.91 (0.65 to 1.28; P = 0.83) for monounsaturated fat, 0.88 (0.64 to 1.21; P = 0.25) for polyunsaturated fat, 0.87 (0.62 to 1.22; P = 0.42) for trans unsaturated fat, and 1.02 (0.75 to 1.39; P = 0.99) for dietary cholesterol. Intakes of red meats, high fat dairy products, nuts, and eggs were also not appreciably related to risk of stroke.Conclusions These findings do not support associations between intake of total fat, cholesterol, or specific types of fat and risk of stroke in men.     

Comments in a Discussion: Differential Rates of d- and l-tyrosine Crystallization

We earlier reported that we had observed quantifiable differences in crystallization rates of D and L tyrosine. It has been suggested that these results were due to the presence of impurities. Here we argue that it is premature to conclude that impurities entirely explain the results. More generally, there is an accumulating weight of evidence that D and L enantiomers display unexpected differences in their physical properties and behavior. These should be taken into account as we attempt to understand the origin of biochirality.     

MAS solid-state NMR studies on the multidrug transporter EmrE

We study the uniformly ¹³C,¹⁵N isotopically enriched Escherichia coli multidrug resistance transporter EmrE using MAS solid-state NMR. Solid-state NMR can provide complementary structural information as the method allows studying membrane proteins in their native environment as no detergent is required for reconstitution. We compare the spectra obtained from wildtype EmrE to those obtained from the mutant EmrE-E14C. To resolve the critical amino acid E14, glutamic/aspartic acid selective experiments are carried out. These experiments allow to assign the chemical shift of the carboxylic carbon of E14. In addition, spectra are analyzed which are obtained in the presence and absence of the ligand TPP+.     

Low-pressure glow discharge in a Xenon/Chlorine mixture

The spatial, electrical, and optical characteristics of a transverse glow discharge and a volume discharge with a spherical anode and plane cathode in low-pressure Xe/Cl₂ mixtures are studied. It is shown that the transverse glow discharge in mixtures with a low chlorine content occupies most of the interelectrode gap and exists in the form of strata. As the total pressure (P≥300 Pa) and the partial chlorine pressure (P(Cl₂)≥80 Pa) increase, a solitary plasma domain with a volume of 1–2 cm³ forms in the discharge gap. It acts as a selective source of UV radiation in the XeCl(D-X) 236-nm, Cl₂ (D′-A′) 257-nm, and XeCl(B-X) 308-nm bands. In certain Xe/Cl₂ mixtures, plasma self-oscillations in the frequency range 1–100 kHz are observed. The current of a low-pressure volume discharge with a spherical anode and plane cathode and the emission from it have both a dc and an ac component. The pressure and composition of the working mixture, as well as the average current of the volume discharge are optimized to attain the maximum emission intensity of the XeCl(D,B-X) bands. Low-pressure volume discharges in xenon/chlorine mixtures can be used as active media in low-pressure large-aperture planar or cylindrical excimer-halogen lamps emitting modulated or repetitive pulsed UV radiation.     

The involvement of ethylene in liatris corm dormancy

Corms of liatris (L. spicata, cv. Callilepsis) show a seasonal dormancy, being most active in the November harvest and least active in June. Storage of dormant corms at 3 °C for about 9 weeks resulted in a complete break of dormancy. This was accompanied by a sharp temporal increase in their rate of ethylene production, which was more pronounced in the buds than in the parenchyma tissue. Application of ethylene to the corms in the form of ethrel solution increased both ethylene production rate and sprouting. The ethylene-forming activity from ACC, measured both in vivo and in vitro, was higher in corms producing more ethylene. However, the content of 1-aminocyclopropane-1-carboxylic acid (ACC) of the corms was inversely related to their ethylene production rate. Ethylene thus seems to be involved in the dormancy control of liatris corms, and its production is apparently regulated mainly by the activity of the membranous ethylene-forming system.     

Natural cell-mediated cytotoxicity in mice treated with total lymphoid irradiation (TLI)

Fractionated total lymphoid irradiation (TLI) of adult (BALB/c × C57BL/6)F₁ mice resulted in transiently augmented natural killer (NK) and natural cytotoxic (NC) cell activities. Thus, 1 day after completion of TLI, NK and NC activities in the spleens of treated mice were lower than controls but values increased and reached a maximum level of 23- to 190-fold above control at 6 days after irradiation, returning to normal levels 9 days later. Cytotoxicity was enhanced after removal of the plastic adherent population. No cytotoxicity was observed against P 815 target cells, which are sensitive to activated macrophages but not to NK. The significance of this modulation of natural cell-mediated cytotoxicity following TLI is discussed.     

Alamethicin-induced pore formation in biological membranes.

The effects of alamethicin on the membrane barrier function of rabbit erythrocytes, human platelets and sarcoplasmic reticulum vesicles, as well as on that of brain microsomes and liver mitochondria of the rat were compared. An upset of the barrier function was observed for plasma membranes of brain microsomes as well as for erythrocyte and platelet membranes at alamethicin concentrations ranging between 25-80 micrograms/ml. The membrane barrier functions of sarcoplasmic reticulum vesicles, of endoplasmic reticulum vesicles of rat brain microsomes, and of liver mitochondria were disturbed at 3-7 micrograms/ml alamethicin. The different sensitivities of plasma and intracellular membranes to alamethicin were supposed to be due to the presence of considerable quantities of cholesterol in plasma membranes as well as to peculiarities of their protein compositions.