Postnatal lung function and protein permeability after fetal or maternal corticosteroids in preterm lambs

Rebello, Celso M., Machiko Ikegami, M. Gore Ervin, Daniel H. Polk, and Alan H. Jobe. Postnatal lung function and protein permeability after fetal or maternal corticosteroids in preterm lambs.J. Appl. Physiol. 83(1): 213-218, 1997.We evaluated postnatal lung function andintravascular albumin loss to tissues of 123-days-gestation pretermsurfactant-treated and ventilated lambs 15 h after direct fetal(n = 8) or maternal(n = 9) betamethasone treatment orsaline placebo (n = 9). Thebetamethasone-treated groups had similar increases in dynamiccompliances, ventilatory efficiency indexes, and lung volumes relativeto controls (P < 0.05). The lossesof ¹²⁵I-labeled albumin fromblood, a marker of intravascular integrity, and the recoveries of¹²⁵I-albumin in muscle and brainwere similar for control and betamethasone-exposed lambs.Betamethasone-treated lambs had lower recoveries of¹²⁵I-albumin in lung tissues andin alveolar washes than did controls (P < 0.01). Although blood pressureswere higher for the treated groups (P < 0.05), all groups had similar blood volumes, cardiac outputs, andorgan blood flows. Maternal or fetal treatment with betamethasone 15 hbefore preterm delivery equivalently improved postnatal lung function,reduced albumin recoveries in lungs, and increased blood pressures.However, prenatal betamethasone had no effects on the systemicintravascular losses of albumin or did not change blood volumes.

     

Enzyme-linked immunosorbent assay (ELISA) using a glycolipid antigen for the serodiagnosis of melioidosis

Abstract The serodiagnosis of melioidosis is commonly performed with tests using protein or polysaccharide as antigen. However, due to the low sensitivity, specificity and difficulty in the preparation of the antigens, more simple, precise and reproducible diagnostic tests were required. A purified glycolipid antigen (GL) which is a specific lipid component of Burkholderia pseudomallei has been used in an ELISA. With this antigen, specific immunoglobulin G (IgG) was detected in 49 out of 50 melioidosis sera. IgG was also detected in 2 out of 185 (Japanese) and 16 out of 181 (Vietnamese) control sera. Thus, the sensitivity was 98.0%, and specificity was 98.9% and 91.1% in the Japanese and Vietnamese sera, respectively. When the ELISA and indirect haemagglutination (IHA) tests were combined, a sensitivity of 100% and specificity of 97.8% were achieved. The advantages of the glycolipid antigen are ease of preparation, stability, high sensitivity and specificity.     

Importance of Fe2+-ADP and the relative unimportance of OH in the mechanism of mitomycin C-induced lipid peroxidation

The mechanism of mitomycin C-induced lipid peroxidation has been studied at pH 7.5, using systems containing phospholipid membranes (liposomes) and an Fe3+-ADP complex with purified NADPH-cytochrome P-450 reductase. Both O2- and H2O2 are generated during the aerobic enzyme-catalyzed reaction in the presence of mitomycin C. Hydroxyl radical is formed in the reaction by the reduction of H2O2. This is catalyzed by the Fe2+-ADP complex in a phosphate buffer or to a lesser extent when in a Tris-HCl buffer. The reduction of Fe3+-ADP to Fe2+-ADP is mainly achieved by O2-. The resulting Fe2+-ADP in the presence of O2 forms a perferryl ion complex which is a powerful stimulator of lipid peroxidation. However, the formation of such an iron-oxygen complex is strongly inhibited by phosphate ions, which do not interfere with the generation of OH radicals. These findings suggest that, since lipid peroxidation occurs in a Tris-HCl buffer (but not in a phosphate buffer), the OH radical is unlikely to be involved in the observed lipid peroxidation process.     

In vivo and in vitro studies on the appearance of LHRH neurons in the hypothalamus of perinatal rats

Summary Ontogenetic development of LHRH-containing neurons was studied by fluorescence and enzyme immunohistochemistry in rats. In in vitro studies, the tissues of the septal-chiasmatic and mediobasal hypothalamic areas of fetal rats on day 16.5 or 18.5 of gestation were trypsinized separately for dissociation of the neural cells, and cultured for several days. Immunopositive reaction against LHRH was first detected in nerve cells derived from both areas of the hypothalamus of the fetuses on days 16.5 and 18.5 of gestation, after 8 and 6 days culture, respectively. The cells were small, and seemed to be bipolar in morphology indicating an axon and arborized dendrites. Immunopositive material occurred in the cell soma as well as in the cellular processes. In in vivo studies, immunopositive material, possibly deposited in nerve fibers, appeared first in OVLT and simultaneously in the external layer of the median eminence of fetuses on day 20.5 of gestation. The immunoreactive fibers increased in number in both parts with development, especially after birth in the median eminence. No immunopositive material was detected within any neural cell bodies nor in the cytoplasm of any ependymal cells.This work was financed by the Ministry of Education, Japan. No. 257008. We would like to thank Dr. Katsuhiko Saito (Department of Surgery, Tokushima University) for his kind advice on the preparation of the antibody used for the immunofluorescence study.     

Fluorescent probe study of temperature-induced conformational changes in cytochrome oxidase in lecithin vesicle and solubilized systems

A protein-bound label, N-(1-anilinonaphthyl-4)-maleimide (ANM), was used to investigate conformational changes in bovine heart cytochrome oxidase. The fluidity of cytochrome oxidase vesicles was monitored by a lipophilic probe, 1,6-diphenyl-1,3,5-hexatriene. The fluroescence intensity and emission anisotropy of these probes were examined between 4 and 60 degrees C in enzyme--dipalmitoyllecithin vesicles, in enzyme--dimyristoyllecithin vesicles, in enzyme--dioleoyllecithin vesicles, and in the soluble enzyme. The temperature-dependent changes in these quantities indicated that there were two types of conformational changes in oxidized cytochrome oxidase: one was attributed to an intrinsic enzyme conformation change which occurred around 20 degrees C, and the other was attributed to a conformational change induced by the lipid phase transition. Although ANM-reactive subunits of cytochrome oxidase in these four lecithin vesicle and solubilized systems were different from each other, subunit I always reacted with ANM in preference to other subunits.     

Single cell protein production from mandarin orange peel

Summary As the hydrolysis of mandarin orange peel with macerating enzyme (40°C, 24 h) produced 0.59 g g^–1 reducing sugar per dry peel compared to 0.36 by acid-hydrolysis (15 min at 120°C with 0.8 N H₂SO₄), the production of single cell protein (SCP) from orange peel was studied mostly using enzymatically hydrolyzed orange peel.When the enzymatically hydrolyzed peel media were used, the utilization efficiency of reducing sugars (%) and the growth yield from reducing sugars (g g^–1) were: 63 and 0.51 for Saccharomyces cerevisiae; 56 and 0.48 for Candida utilis; 74 and 0.69 for Debaryomyces hansenii and 64 and 0.70 for Rhodotorula glutinis. SCP production from orange peel by D. hansenii and R. glutinis were further studied. Batch cultures for 24 h at 30°C using 100 g dried orange peel produced 45 g of dried cultivated peel (protein content, 33%) with D. hansenii and 34 g (protein content, 50%) with R. glutinis, and 38 g (protein content, 44%) with a mixture of both yeasts.     

Metabolism of urea in Chlorella ellipsoidea

The effect of cyanide on ammonia and urea metabolism was studiedwith intact cells of Chlorella ellipsoidea Gerneck, a greenalga which apparently lacks urease. Ammonia uptake was inhibited more readily by cyanide than wasurea uptake. Urea uptake was stimulated by lower concentrationsof cyanide. The addition of cyanide caused the formation ofammonia from some cellular nitrogenous compounds. In the presenceof exogenously added urea, the molar ratio of ammonia accumulatedin the medium to urea taken up exceeded 2.0 as the cyanide concentrationincreased. However, the molar ratio of ammonia actually producedfrom urea nitrogen to urea taken up was less than 1.35 at anyconcentration of cyanide tested. In the presence of higher concentrationsof cyanide, the rate of incorporation of ¹⁵N into amino acidsfrom ¹⁵N-urea was higher than that from ¹⁵N-ammonium sulfate. The results suggest that Chlorella ellipsoidea possesses a pathwaythrough which urea nitrogen is assimilated directly withouta preliminary breakdown to ammonia. (Received October 18, 1976; )     

Changes in intracellular location of DNA polymerase-α during oocyte maturation of the toad,bufo bufo japonicus

Intracellular location of DNA polymerase-α during oocyte maturation of the toad was studied. Quantitative and qualitative changes in the activity of DNA polymerase-α were not observed during the maturational process. Nearly all activity was found in isolated germinal vesicles from full grown oocytes and in enucleated mature oocytes. The cytoplasmic DNA polymerase-α of mature oocytes was recovered at buoyant densities equivalent to microsome by isopycnic centrifugation. These findings indicate that DNA polymerase-α in the germinal vesicle is released into the cytoplasm and binds to the endoplasmic reticulum when the germinal vesicle breaks down.     

Effect of TNF-alpha on prolactin secretion from rat anterior pituitary and dopamine release from the hypothalamus: comparison with the effect of interleukin-1 beta.

The effects of human recombinant interleukin-1 beta and -6 and tumor necrosis factor-alpha (TNF-alpha) on the releases of PRL and dopamine were examined using monolayer cultures of rat pituitary cells and hypothalamic cells. The release of PRL from rat pituitary cells in 30 min was increased about 2-fold (p less than 0.05) by 10(5) U/l interleukin-1 beta, 10(5) U/l interleukin-6 or 100 micrograms/l TNF-alpha. TNF-alpha at 100 micrograms/l significantly increased PRL release within 5 min incubation and this effect continued throughout the next 30 min of incubation. Incubation for 5 min with TNF-alpha caused dose-dependent stimulation of PRL release. These cytokines did not modulate [3H]-dopamine release from primary cultures of hypothalamic cells. These results suggest that these cytokines stimulate PRL release directly at the pituitary gland, without modifying the release of dopamine from the hypothalamus.     

Differential Effects of Nitrate and Light on the Expression of Glutamine Synthetases and Ferredoxin-Dependent Glutamate Synthase in Maize

The effects of nitrate and light on the expression of genesfor glutamine synthetase (GS) isoproteins and ferredoxin-dependentglutamate synthase (Fd-GOGAT) were studied in different organsof maize seedlings by analyzing the levels of the respectivepolypeptides and mRNAs. In roots, the levels of plastidic GSand of a novel, root-specific GS molecule localized in the extraplastidiccompartment were increased markedly by nitrate, whereas Fd-GOGATand cytosolic GS remained at their initial levels. Ammonia wasnot effective in inducing the plastidic GS and Fd-GOGAT butit did induce the novel GS isoprotein. In leaves, cytosolicand plastidic GSs and Fd-GOGAT were present in both mesophyllcells (MC) and bundle sheath cells (BSC). Upon addition of nitrate,the level of plastidic GS increased preferentially in MC, andupon exposure of etiolated seedlings to light, the levels ofplastidic GS and Fd-GOGAT increased in BSC in a coordinatedmanner. The relationship between the expression of genes forGSs and Fd-GOGAT and the physiological role of the GS/GOGATcycle is discussed in terms of the characteristics of nitrogenmetabolism in roots, MC, and BSC. (Received August 11, 1992; Accepted September 21, 1992)