Transactivation of the early SV40 promoter by avian infectious laryngotracheitis virus in avian hepatoma cells

An avian hepatoma cell line has been reported to be suitable for the cultivation of avian laryngotracheitis virus (ILTV) (Scholz et al. (1993) J. Virol. Methods, 273-286; Guo et al. (1993) Am. J. Vet. Res., in press). To provide information for the establishment of avian expression systems and for the construction of avian recombinant viruses, five expression plasmids were constructed to test two avian viral and two mammalian viral promotors for their suitability and strength for gene expression in this cell line. Chicken hepatoma cells were transfected with plasmids carrying the bacterial beta-galactosidase (beta-gal) gene as a reporter gene. The beta-gal gene of three plasmid constructs expressed in both E. coli and avian hepatoma cells, while the beta-gal gene of two other constructs expressed only in avian hepatoma cells. The beta-gal gene expressed independently of any viral infection when under the control of the early Rous sarcoma virus (RSV) promoter or the immediate-early cytomegalovirus (CMV) promoter. However, expression of beta-gal gene under the control of the SV40 early promoter/enhancer and the ILTV TK promoter was greatly potentiated when the transfected cells were co-infected with ILTV. This finding provides a system for the enhancement of gene expression in avian cells, especially when ILTV is used as vector.

[Experimental study on bone formation induced by porous HA-beta-TCP bioceramics]

Three types of HA-beta-TCP active bioceramics which have various porosity and porous diameters were implanted into femurs and muscles of dogs. Histological and biomechanical tests proved that the porous HA-beta-TCP could make the active stage of bone formation moved up in bones and induce new bone formation in muscles. The pores were easily filled with new bones in samples which had smaller porous diameter than samples having larger porous diameter. The final strength after accomplishment of repair process was closely related with porosity. In samples with lower porosity, the proportion of organic bone and the strength were also lower, but in samples with higher porosity the proportion of organic bone and the strength were also higher. Up to the fourth month postoperatively, the strength of HA-beta-TCP with proper porous diameter and porosity which had been implanted into bones was as high as that of organic bone.

Position dispersion and optical limiting resulting from thermally induced nonlinearities in Chinese tea liquid

We employ the z-scan method to distinguish thermally induced nonlinearities from others by varying the beam waist radius and to determine the thermo-optic coefficient of materials. One can attribute the origin of optical nonlinearities of Chinese tea liquid to laser-heating-induced nonlinear refraction while one irradiates the media with a cw He-Ne laser. We also analyze the influence of position dispersion on optical limiting.

Regulation of glycolytically fueled Ca2+ uptake in smooth muscle plasmalemmal vesicles by phosphorylation

A highly purified plasma membrane vesicular preparation from porcine antrum had an endogenous protein kinase activity with substrates of molecular weights of 11, 15, 20.5, 25, 35, 44, 155, and 230 x 10(3). Phosphorylation of the plasma membranes by the endogenous protein kinase activity resulted in a stimulation of initial rates of Ca2+ uptake into inside-out vesicles, which was associated with an increase in the maximum velocity of the Ca2+ pump with no apparent changes in the half-maximal effective concentration for calcium. Because we have previously reported that a membrane-associated glycolytic system may preferentially provide ATP to fuel the Ca2+ pump (9), we examined the effects of phosphorylation on Ca2+ uptake when glycolysis was the sole source of ATP for the pump. We found that the stimulation of Ca2+ uptake by phosphorylation was more pronounced when Ca2+ uptake was supported by glycolysis rather than 2 mM ATP. When ATP was added at a level similar to that produced by endogenous glycolysis, the stimulation of Ca2+ uptake by phosphorylation was comparable to when glycolysis supported the Ca2+ pump. Our observations suggest that the dynamic range (up to threefold) for regulation of the plasmalemmal Ca2+ pump by phosphorylation is considerably larger than previously reported and thus likely to be of physiological significance.

Coordination of vanadyl(IV) cation in complexes of S-adenosylmethionine synthetase: multifrequency electron spin echo envelope modulation study

S-Adenosylmethionine (AdoMet) synthetase requires two freely dissociable divalent cations for activity, and its activity is greatly stimulated by certain monovalent cations (K+, Tl+). Omission of the native Mg2+ cations prevents enzyme-catalyzed reactions, although the substrates and products still bind. Vanadyl (oxovanadium, VO2+) serves as a convenient paramagnetic probe of the substrate-independent, divalent cation binding site in the enzyme. In the present study, multifrequency electron spin echo envelope modulation (ESEEM) is employed to explore the cation's coordination sphere in several functionally relevant complexes. In the substrate complex enzyme.VO2+.ATP.methionine.K+, an equatorially coordinating 14N ligand is found, with Aiso = 4.3 MHz. Selective 15N labeling of the epsilon-amino nitrogens of all lysine residues in the protein reveals that lysine is the source of the ligand. A lysine 14N ligand is also observed in the intermediate complex enzyme.VO2+.AdoMet.PPPi.K+, with Aiso = 4.8 MHz, and in the initial product complex enzyme.VO2+.AdoMet.PPi.K+. In the subsequent product, enzyme.VO2+.AdoMet.K+ (formed upon dissociation of PPi), the methionyl amino nitrogen of AdoMet coordinates VO2+ (Aiso = 5.3 MHz), and the lysine ligand is lost. In each complex, the monovalent cation activator can be changed from K+ to Tl+ or Na+ with no effect on the ESEEM spectra. Combination of the ESEEM data from this study with previous CW data [Markham, G. D. (1984) Biochemistry 23, 470-478] leads to identification of three of the equatorial ligands to VO2+ and places constraints upon the identity of the fourth ligand, in both the substrate and product complexes. A hypothetical outline of changes in the metal coordination scheme during the reaction is presented, based upon these results.

Mechanisms for laser-induced functional damage to silicon charge-coupled imaging sensors

We measured the functional degradation of silicon CCD photodetector arrays when subjected to Nd:YAG laser irradiation at 1.06 µm by 10-ns pulses. Operational tests such as dark leakage, point-spread function, and modulation transfer function were developed for testing individual pixels and applied to the testing of locally laser-damaged CCD arrays. Testing revealed that the primary failure mechanism was the spreading of the point-spread function in the direction of clocked charge motion that resulted from a decreased depth of potential wells within the laser-damaged spot. Lesser degradation was observed at pixels near the damaged spot that were served by clock lines that traversed the damage spot. This damage behavior was correlated with decreased breakdown voltage and increased leakage current between adjacent clock lines. Subsequent morphological and TEM examination of similarly constructed chips indicated that laser heating of the polysilicon clock lines led to degradation of the adjacent isolation oxide between clock lines. Functional damage occurred at locations where two clock lines were very close to each other, and the thin oxide layer separating them was subjected to high temperatures that resulted from melting of the neighboring polysilicon.

The receptors activated by exogenous and endogenous opioids in the superior cervical ganglion of the cat

Nicotinic transmission in the superior cervical ganglion of the cat was studied in vivo and in vitro by recording the postganglionic compound action potential evoked, under partial block with hexamethonium, by supramaximal 0.2 Hz stimulation of the cervical sympathetic trunk. The compound action potential was depressed following a stimulus train (5 Hz, 40 s) applied to the same set of axons. The inhibition was antagonized by naloxone, suggesting mediation by endogenous opioids. Agonists selective for mu-, delta- and kappa-opioid receptors, injected into the arterial supply of the in situ ganglion or added to the perfusion fluid in the in vitro ganglion, also produced a naloxone-sensitive inhibition of the compound action potential. The synaptic inhibition was antagonized by the delta-selective antagonist ICI 174,864 and by the mu-selective antagonist CTAP, but not by the kappa-selective antagonist Nor-BNI. These results suggest that all three main types of opioid receptors are present in the ganglion but only mu- and delta-receptors are involved in the inhibition of ganglionic transmission mediated by the endogenous opioids.

Mapping of ben genes of Pseudomonas aeruginosa

Four ben genes responsible for the conversion of benzoate to catechol in Pseudomonas aeruginosa PAO have been mapped to a 4.6 kb KpnI fragment, ben-1 and ben-4 were known to be separate genes but now ben-1508 has been found to be different from ben-2. The two genes were distinguished by Tn5 mutagenesis of a cosmid clone and deletion mapping. It is likely that the four genes mapped (ben-4, ben-2, ben-1508 and ben-1) correspond to the previously characterized benR (regulatory gene) and benABC (benzoate dioxygenase) respectively.

Occurrence of a particular base substitution (3243 A to G) in mitochondrial DNA of tissues of ageing humans

Allele-specific polymerase chain reaction has been used to demonstrate the occurrence, during the human ageing process, of the mutation A to G at nucleotide position 3243 on mitochondrial DNA. An oligonucleotide with a 3'-end specific to this mutation was designed to selectively amplify DNA bearing this mutation under annealing temperature conditions that efficiently discriminate between normal and mutant mitochondrial DNA templates. Seven out of 38 adult tissues tested were found to contain this mutation, whereas the mutation could not be detected in any of the 16 infant tissues analyzed. The present demonstration of an age-related point mutation adds to the growing list of mutations in human mitochondrial DNA, till now almost exclusively large deletions, that accumulate in human tissues as a function of age. The method described here has general application in the detection of other age-related point mutations in human mitochondrial DNA.

[Capillary blood viscosimeter of the microcomputer]

On the basis of specific property of non-Newtonian fluid (blood) we have worked out the formula of capillary blood viscosimeter:sheat stress tau alpha = alpha rho gh/2L shear rate f (tau alpha) = 1/pi alpha 3 [3q + h(dq/dh)] and designed and produced the prototype. Repetition experiments have indicated that the property of the instrument is stable, and a comparison of the prototype with the cone and plate viscosimeter has demonstrated the reliability of the measurements.

Treatment of 121 patients with malignant effusion due to advanced lung cancer by intrapleural transfer of autologous or allogeneic LAK cells combined with rIL-2

Lymphocytes isolated from malignant pleural effusion in patients with advanced lung cancer or from allogeneic peripheral blood of healthy donors were induced to become LAK cells after in vitro culture with rIL-2. One hundred and twenty-one patients with malignant effusions were treated by intrapleural transfer of autologous or allogeneic LAK cells combined with rIL-2. The effusion disappeared in 71 patients (58.6%) and was significantly decreased in 45 patients (36.2%). Five patients did not respond to treatment. Tumor cells in pleural effusions disappeared or were significantly decreased in number, whereas the lymphocytes were significantly increased in number in all responders. Except for transient fever in 10 patients, no serious side effect was observed.

Acadesine prevents oxidant-induced damage in the isolated guinea pig heart

Acadesine is a cardioprotective nucleoside that can attenuate postischemic contractile dysfunction in the isolated heart even if administered at reperfusion, thereby implying an effect on a reperfusion-induced component of injury. Consequently, the effects of acadesine on the maintenance of cardiac function were evaluated in isolated guinea pig hearts in which the perfusion buffer was subjected to electrolysis to produce a mixture of free radicals and oxidants that have been implicated in reperfusion injury. A reduction of left ventricular developed pressure to 38 +/- 3% at 10 min after electrolysis was prevented by acadesine in a concentration-dependent manner (EC50 1 microM). Hypochlorous acid (HOCl) is a principal oxidizing species implicated in electrolysis-induced myocardial damage, and it is a major oxidant produced by neutrophils. Isolated hearts, perfused with HOCl to induce damage, were also protected by acadesine (EC50 1-3 microM). In addition, acadesine protected alpha 1-antiproteinase (alpha 1-AP) against inactivation by 30 microM HOCl with an EC50 of approximately 10 microM, demonstrating that acadesine reacts rapidly enough with HOCl to protect important biological targets. Additionally, acadesine scavenged the hydroxyl radical with a second-order rate constant of 5.0 x 10(9) M-1 s-1. In contrast, acadesine had no effect on superoxide anions generated from either xanthine-xanthine oxidase or hydrogen peroxide-mediated peroxidation. The free base of acadesine 5-amino-4-imidazole carboxamide (AICA) also reduced HOCl and attenuated the electrolysis-induced cardiac injury. However, unlike the parent molecule acadesine, AICA was not protective in the isolated heart subjected to ischemia and reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Physical and psychosocial side effects of antepartum hospital bed rest

The purpose of this study was to describe the physical and psychosocial effects of antepartum hospital bed rest on pregnant women and to determine whether the symptoms exhibited differed from those exhibited by pregnant women not on bed rest. Women on complete bed rest (n = 10) had greater gastrocnemius muscle dysfunction, weight loss, and dysphoria than women on partial bed rest (n = 7) or no bed rest (n = 18). Separation from family was the greatest hospital stressor. Postpartum recovery from the side effects of bed rest was prolonged and included symptoms of muscular and cardiovascular deconditioning. The severity of side effects appeared to be directly related to the degree of severity restriction.

Interaction of dichloromethane (methylene chloride) with the nitrous oxide reductase from Wolinella succinogenes

Nitrous oxide reductase from Wolinella succinogenes was tested for benzyl viologen cation (BV(+))-chlorinated methane oxidoreductase activity, using di-, tri- and tetra-chloromethanes, and for the inhibition of BV(+)-N2O oxidoreductase activity by these chloromethanes. No BV(+)-chlorinated methane oxidoreductase activity was detected. Any such activity, if it exists, must be less than 0.1% of the BV(+)-N2O oxidoreductase activity of the enzyme. Inhibition of the BV(+)-N2O oxidoreductase activity by dichloromethane was detected and was apparently reversible and non-competitive, as is the case with the small metal-ligand type inhibitors of the enzyme (e.g. acettlene, azide, cyanide and carbon monoxide). Trichloromethane was a weaker inhibitor and inhibition was not detected with tetrachloromethane.

Use-dependent fade and two-rate recovery of a naloxone-sensitive inhibition in the cat superior cervical ganglion

In anaesthetized cats, a short train to the cervical sympathetic trunk (CST), of frequency between 0.5 and 5.0 Hz, inhibited the postganglionic compound action potential (CAP) evoked by a test shock to the CST. When the CST was split into two bundles, the inhibition was obtained both homosynaptically and heterosynaptically. The inhibition was antagonized by naloxone and enhanced by peptidase inhibitors. Leu-enkephalin (ENK), injected into the arterial supply of the superior cervical ganglion (SCG) depressed the CAP. The ENK-evoked inhibition was antagonized by naloxone, enhanced by peptidase inhibitors and was occluded by the train-evoked inhibition. After prolonged stimulation of the CST (5-20 min at 5 Hz), the inhibition produced by a short train was depressed (faded). The fade was greater the longer the stimulation. After 20 min of stimulation the inhibition was absent. At this time the depressant effect of ENK was unchanged. When only one bundle of the split CST was stimulated at 5 Hz for 20 min, only the inhibition produced by that bundle faded, although both bundles converged onto a common set of ganglion cells. Thus, the fade is not due to receptor desensitization but more likely to failure to release the inhibitory mediator by the overstimulated axons. When, after 20 min of 5 Hz stimulation, no further stimuli were applied, the inhibition recovered in 60 min (fast recovery). However, recovery was slower when stimulation lasted longer than 20 min. Recovery took three days when stimulation lasted 80 min (slow recovery). The inhibition was markedly depressed after application of colchicine to the CST three days earlier.(ABSTRACT TRUNCATED AT 250 WORDS)

Optical limiting by chemically enhanced bacteriorhodopsin films

The optical limiting properties of a thin film (~150 microm) of chemically enhanced bacteriorhodopsin under cw laser illumination is investigated. The effective nonlinearity n(2) of the film is measured with the z-scan method. Anomalous absorption at different wavelengths as a function of illumination intensity is observed.

Mapping of the ben, ant and cat genes of Pseudomonas aeruginosa and evolutionary relationship of the ben region of P. aeruginosa and P. putida

Genes responsible for the utilization of benzoate, anthranilate or catechol (ben, ant, cat) of Pseudomonas aeruginosa PAO were mapped precisely using a cosmid clone carrying all these genes. Genes were localized either by subcloning and complementation or by Tn5 mutagenesis and mapping of the Tn5 insertions. To achieve this, a novel Tn5 mutagenesis procedure was developed by constructing a Tn5 insertion derivative of the Escherichia coli strain S17-1. Preliminary mapping of the ben cat genes of P. putida PPN was accomplished by complementation using a PPN cosmid bank. Sequence homology was demonstrated by Southern hybridization between the ben regions of both P. aeruginosa and P. putida, implying an evolutionary relationship of this chromosomal region of these two pseudomonads.

Photosensitization with anticancer agents. 18. Perylenequinonoid pigments as potential photodynamic therapeutic agents: preparation and photodynamic properties of amino-substituted hypocrellin derivatives

Perylenequinonoid pigments have demonstrated several photodynamic therapeutic advantages over the commonly used hematoporphyrin derivatives. Certain new amino-substituted hypocrellin B derivatives have been prepared, and both direct and reductive aminations of hypocrellin B are described. The photophysical and photochemical properties of the amino-substituted hypocrellin B derivatives were investigated, and their significantly enhanced red absorptivities and strong 1O2-generating functions qualify them as promising photodynamic therapeutic agents. In addition, the superoxide anion radical was also determined to be implicated in the photosensitization of the amino-substituted hypocrellin B derivatives.

Bradyrhizobium japonicum rhizobitoxine genes and putative enzyme functions: expression requires a translational frameshift

Some strains of Bradyrhizobium japonicum produce rhizobitoxine, a phytotoxin that causes foliar chlorosis on susceptible host plants. We have previously obtained Tn5-induced rhizobitoxine null mutants of B. japonicum. DNA sequence analysis of the region surrounding two Tn5 insertions identifies two overlapping open reading frames. The first open reading frame (rtxA) predicts a 54-kDa protein for which the N-terminal 280 residues have sequence similarity to serine: pyruvate aminotransferase. The sequence homology to aminotransferase is consistent with the involvement of this gene in serinol production, a likely intermediate in rhizobitoxine biosynthesis. Previously, a mutant in this open reading frame was shown not to make serinol. The predicted amino acid sequence of the second open reading frame (rtxB) has similarity to yeast O-acetylhomoserine sulfhydrolase. This enzyme function is similar to that required for dihydrorhizobitoxine synthase. The DNA sequence shows that the rtxB open reading frame overlaps rtxA, suggesting that expression of rtxB requires a -1 translational frameshift. Protein expression experiments demonstrate production of an RtxAB fusion protein. The ability of the overlapping rtxA and rtxB sequences to promote a translational frameshift was confirmed in a heterologous expression system. In Escherichia coli, this frameshift appears to be unusually efficient, occurring at a frequency of 80-90%.

Cadmium-induced arteriolar constriction in skeletal muscle microcirculation

Cadmium, an environmental pollutant, is known to induce hypertension in animal models, in part via an increase in peripheral vascular resistance. Since prior studies have investigated the vascular effects of cadmium using large, nonresistance arteries, we directly assessed cadmium's action on resistance size arterioles in skeletal muscle using the intact rat cremaster muscle preparation. Cadmium evoked a concentration-dependent constriction of the large arterioles (120 to 50 microns in diameter) but elicited no change in the diameter of smaller arterioles (30 to 15 microns). Blockade of alpha-adrenergic receptors did not diminish the constrictor response of the larger arterioles to cadmium, but bathing the cremaster muscles with a solution containing low calcium attenuated the arteriolar constriction to cadmium. Calcium repletion caused the arterioles to constrict further. These observations provide the first direct evidence that cadmium constricts resistance arterioles in skeletal muscle. The cadmium constriction: (1) is selective for the large arterioles, (2) is not mediated by alpha-adrenergic receptors, and (3) is influenced by the extracellular level of calcium. We conclude that arteriolar constriction in skeletal muscle tissue may play a role in the hypertensive actions of cadmium.