The role of polarization of Xe by di- and monovalent cations in 129Xe NMR studies in zeolite A

We consider the role of polarization in the adsorption of Xe in zeolites of type A by direct comparative analysis of the adsorption isotherms, distributions of occupancies, and 129Xe NMR chemical shifts of Xe(n) in cages containing CaxNa12-2x ions per alpha cage (x = 0, 1, 2, 3, 5). We find that the qualitative trends in the adsorption isotherms, and in the progressions of Xe(n) chemical shifts (for n = 0-8 in cages with x = 0, 1 Ca2+ ions and for n = 0-5 in cages with x = 2, 3 Ca2+ ions) upon increasing the level of Ca2+ ion for Na+ ion substitution could only be accounted for by including polarization of the Xe atom by the zeolite framework and its ions. This system, which permits observation of individual Xe(n) peaks and of directly comparable adsorption isotherms in several cage types, provides a good model system for the interpretation of the more general case in which only the overall average 129Xe NMR chemical shift is observed in open network zeolites, arising from free exchange of Xe among cavities of variable occupancy and variable cation distribution.     

Regional anticoagulation with sodium citrate: chronic utilization in the hemodialysis patient

We used an alternative technique for regional citrate anticoagulation (citrate 0.48 Mol; bicarbonate containing dialysate with Ca 1.75 Mmol) in three patients at chronic risk of bleeding and for a mean follow-up period of ten months. No bleeding recurrence was observed nor any complication related to citrate. Hemoglobin and hematocrit rose without transfusions. Serum bicarbonate increased during the first four months of treatment. No significant change was observed in serum calcium nor serum sodium concentration.     

The binding and utilization of hemoglobin by Prevotella intermedia

Personalism in ethics denotes any system based upon the value of the person. Several versions of personalist morals have been developed over the past 50 years. Some have had particular interest in the field of medical ethics. Here the question is being studied about one such system, the so-called Leuven personalist morals and its usefulness in today's world of bioethics. In order to test the usefulness of this system the case of artificial insemination is examined both in the early 1970s in the context of the Leuven clinics and, subsequently, in the 1990s in a US policy document. The investigation reveals strengths and weaknesses of this personalism. Regarding AID it reveals unresolved oppositions. The conclusion seems to be that this personalism had, no doubt, a profound impact upon medical ethics within its own circle but, as regards the universal usefulness of the system, serious doubts remain.     

The utilization of dipeptides containing L-arginine by chicken macrophages

L-Arginine is the precursor of NO, a cytotoxic agent of macrophages. Studies were carried out to determine whether dipeptides containing arginine can be utilized by lipopolysaccharide (LPS)-activated avian macrophages for NO production. A chicken macrophage cell line, the HD11 cell, was used in all experiments. Peptidase activities were observed in fetal bovine serum (FBS) and macrophage serum free medium (Mac-SFM). Therefore, the utilization of dipeptides by macrophages was examined using Dulbecco's modified Eagle medium (D-MEM), a chemically defined medium, in short-term culture without FBS. Nitrite accumulation in the culture medium was used as the indicator of NO production. At concentrations of 0.15 mM in the culture media, L-leucinyl-L-arginine was 89% as effective as L-arginine in providing substrate for NO production. L-Argininyl-L-leucine was 38% as effective as L-arginine. The effectiveness increased to 93 and 58%, respectively, when the concentrations of dipeptides and arginine were 1.0 mM. Both values were slightly higher in a second experiment (97 and 70%, respectively). L-Lysine (10 mM) inhibited nitrite formation from all three sources of L-arginine. In studies of initial rates of transport by HD11 cells in Hanks Balanced Salts solution (HBSS), both L-argininyl-L-leucine and L-leucinyl-L-arginine inhibited arginine uptake. As lysine and arginine share a common transporter for cationic amino acids and are known to compete for transport, these studies suggest that the peptides were hydrolyzed extracellularly, yielding arginine that was transported into the cell where it served as a substrate for NO synthesis.     

Nitrogen metabolism of broilers fed 15-N labeled wheat. 4. 15-N concentration in muscles and nitrogen utilization

Broilers were fed 15N labelled wheat and the concentration of the labelled isotope in muscular tissue was determined. A negative correlation was found to exist between the percentage proportion of N in the muscle fractions and the level of 15N frequency established 12 hrs after administration of the labelled ration. Higher rates of tracer incorporation were observed in the muscles of legs and other muscles (predominatly red muscles) than in pectoral muscles (white muscles). The heart was shown to exhibit the lowest N content and the highest level of 15N frequency of all muscle fractions. In view of the fact that some specific difficulties will arise when certain factors (trace elements, vitamins, ergotropic substances, genetic factors) which influence the N metabolism of fattening poultry, are estimated on the basis of the conventional N balance trials the present tracer technique is recommended for use as an alternative method in studies of the kind just described. In the present trial 20% of the wheat N were utilized for the production of meat N in muscular tissue.     

The effect of photoperiod and nutrition on ascites incidence in broilers

Light restriction was used to restrict growth of male broilers up to 41 days of age. Dietary energy and lysine were also investigated for their interaction with slowed growth rate. A total of 1440 male broilers was used in each of two trials. Light restriction significantly reduced body weights at 22 days (P < or = 0.05) but not at 52 days. Restricting early growth by photoperiod for the 3-to-41-day period reduced deaths due to ascites. Neither dietary energy nor lysine affected mortality from ascites. These results suggest that manipulation of photoperiod for young broilers is a useful way to limit early growth and subsequent ascites mortality.     

A learning resources centre: its utilization by medical students

The 17 described genomic species (DNA groups) of the genus Acinetobacter, including the type strains of the seven named species, were studied by using a multiplex PCR. The multiplex PCR assay combined two primer sets (rA1 and rA2 for recA gene target; rib1 and rib2 for 16S rDNA sequence) in a single reaction. Restriction analysis with two enzymes (Mbol and Hinfl) of the enzymatically amplified products allowed identification of all genospecies. This technique proved to be a rapid and reliable method for the identification of the Acinetobacter genomic species including the closely related DNA groups (1, 2, 3, 13). The results of this study suggest that the proposed method can be used for the identification of Acinetobacter spp. and as such may help to elucidate the ecology and clinical significance of the different species of this genus.     

The importance of sodium pyruvate in assessing damage produced by hydrogen peroxide

OBJECTIVES: The external striated urethral sphincter (rhabdosphincter) is a tubular muscle sleeve that extends from the prostato-membranous urethra and perineal membrane to the bladder neck. The male rhabdosphincter neuroanatomy remains unclear, and a better understanding of its innervation may provide insight into potential modifications of radical pelvic surgery to improve urinary continence. METHODS: Fresh cadaveric dissections of 12 male hemipelves were undertaken to investigate the neuroanatomy of the urinary rhabdosphincter. RESULTS: Neuroanatomic courses of the nerve supply to the rhabdosphincter revealed that, in the perineum, the perineal nerve (a terminal branch of the pudendal nerve) provided branches directly to the bulbospongiosus muscle and the urinary rhabdosphincter. In the pelvis, the course of the pelvic nerve was as follows: (1) arising from the inferior hypogastric plexus, it had a weblike course beneath the muscle fascia of the levator ani muscle; (2) traveling posterolateral to the rectum, it gave many branches that perforated into the lateral rectum; and (3) at the level of the prostatic apex, still beneath the levator ani muscle fascia (superior fascia), it sent multiple direct branches to the inferolateral aspect of urinary rhabdosphincter. The pudendal nerve traversed the pelvis in the pudendal canal, and, before leaving the pelvis to enter the perineum, it gave an intrapelvic branch that courses with the pelvic nerve to innervate the rhabdosphincter. CONCLUSIONS: Our understanding of the neuroanatomy of what may be the continence nerves has been improved by fresh cadaveric dissection. The rhabdosphincter receives nerve fibers from the pelvic nerve and dual innervation from an intrapelvic branch and a perineal branch of the pudendal nerve. Better understanding of these anatomic findings may have potential surgical significance with respect to improvement in postoperative urinary continence.     

The sulphation of nickel and cobalt ferrites and sulphides by molten sodium pyrosulphate and sodium bisulphate

Abstract

Synthetic ferrites and sulphides of nick-el and cobalt were sulphated in the presence of molten sodium pyrosulphate and sodium bisulphate. The ferrites may be sulphated readily; hence it is unlikely that they would retain unreacted nickel or cobalt during the sulphation of the corresponding oxides.

In the presence of either sodium pyrosulphate or sodium bisulphate, nickel and cobalt sulphides may be sulphated directly, but at higher temperatures the oxide forms as an intermediate compound.

Résumé

Des ferrites et des sulfures synthétiques de nickel et de cobalt ont été sulfatés en présence de pyrosulfate et de bisulfate de sodium fondus. Les ferrites peuvent être facilement sulfatés, dès lors il parait improbable qu'ils accaparent du nickel ou du cobalt durant la sulfatation des oxydes correspondants.

En présence, soit de pyrosulfate de sodium soit de bisulfate, les sulfures de nickel et de cobalt peuvent être sulfatés directement, mais à températures élevées, il y a formation d'oxyde en tant que composé intermédiaire.     

The utilization of amino acids and urea by human oral fluid

Incubation of mixed human saliva with arginine, ornithine, and proline for 30 min to 2 h at 40 degrees C leads to an appreciable consumption of the above amino acids. The rate of utilization is 0.2 to 0.5 ncat/ml of saliva. The rate of urea loss is higher by an order of magnitude: up to 11 ncat/ml. Putrescin, urea (after incubation with arginine), and ammonium are identified as the products of these reactions. The biological significance of such reactions is believed to consist in neutralization of carbohydrate fermentation products. The detected consumption of amino acids and urea indicates that mixed human saliva contains urease, arginase, ornithine decarboxylase, and, probably, proline reductase. Since the origin of these enzymes is probably bacterial, changes in their activity in the saliva can be regarded as an indicator of dysbacteriosis and a diagnostically important parameter.     

The taste of sodium

Sodium is crucial to physiological function. The responsibility for detecting it is assumed by the taste system, which devotes perhaps one quarter of its resources to the task. Sodium is transduced by passage into a subset of receptor cells, whose activity is relayed to the brain through a discrete gustatory channel. Responses in hindbrain, thalamus, and gustatory cortex identify the quality and concentration of sodium on the tongue. Coding of reinforcement may begin with the pons and ventral forebrain, particularly the lateral and medial hypothalamic nuclei. When body stores are sufficient, behavioral preference for sodium is mild, encompassing low concentrations and marked by weak avidity. This languid response disappears during sodium shortages. Avidity increases, and hypertonic concentrations are most preferred. This behavioral change may result from altered responsiveness in sodium-specific neurons that offer the sodium signal access to mechanisms of reinforcement. Thus, the taste system detects and recognizes sodium, and accords it a reward value commensurate with the needs of the animal.     

火焰原子发射光谱法直接测定钠盐表面活性剂中钠

在加热下用硝酸(1+1)-OP溶液溶解钠盐表面活性剂样品,配制成均匀透明的样品溶液。为消除电离干扰,取适量样品溶液加入消电离剂硝酸钾溶液配制成试液,喷入空气-乙炔火焰测定钠,建立了火焰原子发射光谱法直接测定钠盐表面活性剂中钠的分析方法。以空白溶液为参比,用工作曲线法测定。对样品溶解条件、电离干扰、试液与空白溶液粘度一致性进行了考察。测定结果的相对标准偏差小于2.4%,加标回收率97.8%~105.0%,线性范围0~1.6μg/mL,方法简便。     

A protein phosphatase is involved in the inhibition of histone deacetylation by sodium butyrate

Treatment of cells with sodium butyrate is known to increase histone acetylation by inhibiting deacetylases. Here we have observed, in cultured hepatoma cells, that the potent serine-threonine phosphatase inhibitors, okadaic acid or calyculin A, inhibited phosphatase activity and concomitantly decreased the histone acetylation classically maintained by sodium butyrate. These results suggest that a protein phosphatase may mediate the sodium butyrate effect on deacetylases. Since we have previously found that such a protein would also mediate the sodium butyrate effect on gene expression, we propose that a phosphatase activity constitutes an early and essential step in the sodium butyrate-triggered signalling pathway.     

The chemistry and kinetics of oxidized copper sulfiding by sodium thiosulfate

The conditions of copper sulfide formation as a result of the interaction between sodium thiosulfate and oxidized compounds of copper are studied. The effects of precipitator consumption, acidity, and temperature on this process are studied. It is found that copper can be quantitatively extracted from solutions by sodium thiosulfate in the form of covelline and chalcosine. The kinetics of the interaction between sodium thiosulfate and oxidized copper minerals in the temperature range from 40 to 100°C with 1.5 mol of Na₂S₂O₃ per 1 mol of the metal extracted are studied. Equations describing typical kinetic curves of precipitation are selected. The reaction rate constants are determined.