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  • 1
    Electronic Resource
    Electronic Resource
    Stabilization of a cold cathode electron beam glow discharge for surface treatment (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 4118-4120 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 μA was found to limit the shot to shot current variation to within 1.5%. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365723
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  • 2
    Electronic Resource
    Electronic Resource
    Adenosine inhibits L-type Ca2+ current and catecholamine release in the rabbit carotid body chemoreceptor cells (1999)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 11 (1999), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In an in vitro preparation of the intact carotid body (CB) of the rabbit, adenosine (100 μm) inhibited hypoxia-induced catecholamine release by 25%. The specific A1 antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 1 μm) prevented the inhibition and increased the response to hypoxia further. In isolated chemoreceptor cells from the same species, adenosine inhibited voltage-dependent Ca2+ currents by 29% at 1 μm (concentration producing half-maximal inhibition, IC50 = 50 nM). This inhibition was mimicked by R(–)N6-(2-phenylisopropyl)-adenosine and 2-chloroadenosine (1 μm), two purinergic agonists poorly active at the intracellular (‘P') site, and persisted in the presence of dipyridamole (a blocker of adenosine uptake; 1 μm) and was fully inhibited by 8-phenyltheophylline (10 μm). The A1 antagonists DPCPX (10 μm) and 8-cyclopentyl-1,3-dimethylxantine (0.1 μm) inhibited the effect of adenosine by 93% (IC50 = 0.14 μm) and 59%, respectively. The inhibition of the Ca2+ current (ICa) was reduced by nisoldipine (an L-type Ca2+ channel antagonist) by nearly 50%, and was unaltered by omega-conotoxin GVIA, a blocker of N-type Ca2+ channels. Adenosine did not affect the voltage-dependent Na+ current (INa) or K+ current (IK.). We conclude that adenosine A1 receptors are located in chemoreceptor cells and mediate the inhibition of L-type Ca2+ channels and thereby the release of catecholamines produced by hypoxia. The data also indicate that endogenous adenosine acts as a physiological negative modulator of the chemoreceptor cell function. The previously reported excitatory action of adenosine on the activity of the sensory nerve of the CB is discussed in terms of a balance between the inhibition mediated by A1 receptors and the excitation mediated by A2 receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.1999.00470.x
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  • 3
    Electronic Resource
    Electronic Resource
    Cholera and Pertussis Toxins Reveal Multiple Regulation of cAMP Levels in the Rabbit Carotid Body (1996)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 8 (1996), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It is known that hypoxia (PO2∼66–18 mm Hg), acting via unknown receptors, increases carotid body cAMP levels in Ca2+-free solutions, indicating that low PO2 activates adenylate cyclases independently of the action of the released neurotransmitters. The aim of the present work was to investigate the involvement of G proteins in the genesis of the basal level of cAMP and on the increase in cAMP induced by low P02. In carotid body homogenates, cholera toxin- and pertussis toxin-induced [32P] ADP-ribosylation of two protein bands of =42 and 45 kDa, and =39 and 40 kDa respectively; in both cases, prior incubation of the carotid bodies with the toxins reduced [32P] ADP-ribosylation by 〉90%. In intact carotid bodies, cholera toxin treatment increased cAMP levels more in normoxic than in hypoxic organs, indicating that hypoxia releases neurotransmitters acting on receptors negatively coupled to adenylate cyclases. Cholera toxin-treated carotid bodies incubated in Ca2+-free solution had identical cAMP levels in normoxia and in hypoxia. In pertussis toxin-treated normoxic carotid bodies the cAMP level was close to control, but in pertussis toxin-treated hypoxic carotid bodies cAMP rose to a level similar to those seen in normoxic cholera toxin-treated organs, indicating that low PO2 releases neurotransmitters acting on receptors positively coupled to adenylate cyclases. Pertussis toxin-treated carotid bodies incubated in Ca2+-free solution lost their capacity to increase cAMP in response to hypoxia, indicating that a G protein sensitive to pertussis toxin is needed for this response. This implies that the carotid bodies express a pertussis toxin-sensitive G protein positively coupled to adenylate cyclases, or that a Gs protein requiring the cooperative action of Go/Gi donated by subunits mediates the increase in cAMP level produced by hypoxia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1996.tb01195.x
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  • 4
    Electronic Resource
    Electronic Resource
    Porokeratotic eccrine ostial and dermal duct naevus (1995)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 132 (1995), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1995.tb08699.x
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  • 5
    Electronic Resource
    Electronic Resource
    Induction of Antibodies against Salmonella typhi OmpC Porin by Naked DNA Immunization (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 772 (1995), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1995.tb44761.x
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  • 6
    Electronic Resource
    Electronic Resource
    Construction of L-lysine-overproducing strains of Brevibacterium lactofermentum by targeted disruption of the hom and thrB genes (1996)
    Springer
    Applied microbiology and biotechnology 46 (1996), S. 554-558 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The mobilization of plasmids from gram-negative Escherichia coli to gram-positive Brevibacterium lactofermentum, mediated by P-type transfer functions, was used to construct disrupted mutants blocked specifically in the homoserine branch of the aspartate pathway. The mutant strain B. lactofermentum R31 showed an efficiency of conjugal transfer two to three orders of magnitude higher than that of the wild-type strain B.␣lactofermentum ATCC 13869. The hom- and thrB- disrupted mutants of B. lactofermentum ATCC 13869 were lysine overproducers. B. lactofermentum R31 mutants do not overproduce lysine because R31 is an alanine-overproducing strain and channels the pyruvate needed for lysine biosynthesis to the production of alanine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530050860
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  • 7
    Electronic Resource
    Electronic Resource
    A set of Hansenula polymorpha integrative vectors to construct lacZ fusions (1999)
    Springer
    Applied microbiology and biotechnology 53 (1999), S. 23-29 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A set of YEp Saccharomyces cerevisiae-based, integrative Hansenula polymorpha plasmids was constructed to express lacZ gene under yeast gene promoters. The HpLEU2 and HpURA3 genes were used both as markers and to target the integration of plasmids into the corresponding H. polymorpha genome locus. The frequency of transformation reached with these plasmids linearised either in HpLEU2 or HpURA3 was around 100 transformants per microgram of plasmid DNA; in all transformants checked by Southern blotting the plasmid was integrated into the genome locus corresponding to the gene plasmid marker. PCR showed that about 50% of the transformants contained more than one plasmid copy per genome. Experiments carried out using the developed plasmids to determine the strength of the gene promoters involved in nitrate assimilation in H. polymorpha revealed that, in the presence of nitrate, the nitrate reductase gene promoter (YNR1) was the strongest, followed by nitrite reductase (YNI1) and nitrate transporter (YNT1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530051609
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  • 8
    Electronic Resource
    Electronic Resource
    Total immunoreactive proinsulin, immunoreactive insulin and specific insulin in relation to conversion to NIDDM: the Mexico City Diabetes Study (1997)
    Springer
    Diabetologia 40 (1997), S. 830-837 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Insulin ; proinsulin ; insulin secretion ; non-insulin-dependent diabetes mellitus.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although insulin resistance and decreased insulin secretion are characteristic of established non-insulin-dependent diabetes mellitus (NIDDM), which of these metabolic abnormalities is the primary determinant of NIDDM is still controversial. A disproportionate increase in the proinsulin to insulin ratio has been proposed as a marker of compromised insulin secretion. We examined the association of fasting immunoreactive insulin (which cross-reacts with proinsulin), specific insulin (which does not cross-react with proinsulin), total immunoreactive proinsulin (or insulin precursors), and the fasting proinsulin/specific insulin ratio to the risk of developing NIDDM in the 3.25-year follow-up of the Mexico City Diabetes Study. These measurements were made in 85 subjects who subsequently converted to NIDDM (prediabetic subjects) and in 85 age and gender matched subjects who remained non-diabetic at follow-up (control subjects). Immunoreactive insulin, proinsulin and the proinsulin/specific insulin ratio were significantly higher in prediabetic than in control subjects. However, the relation between specific insulin and the development of NIDDM was weaker than for proinsulin or immunoreactive insulin. After further adjustment for obesity, body fat distribution and glucose tolerance status, proinsulin and the proinsulin/specific insulin ratio, but not specific or immunoreactive insulin, predicted conversion to NIDDM. A high proinsulin/specific insulin ratio predicted conversion to NIDDM both in subjects with normal and those with impaired glucose tolerance at baseline. We conclude that in prediabetic subjects increased proinsulin, a marker of islet cell distress or compromised insulin secretion, is associated with rapid conversion (within 3.25 years) to NIDDM even in obese populations. [Diabetologia (1997) 40: 830–837]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250050756
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  • 9
    Electronic Resource
    Electronic Resource
    Marine Bacteria Tolerant to Chlorophenols (1999)
    Springer
    Bulletin of environmental contamination and toxicology 62 (1999), S. 272-277 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001289900870
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  • 10
    Electronic Resource
    Electronic Resource
    Carbon monoxide inhibits hypoxic pulmonary vasoconstriction in rats by a cGMP-independent mechanism (1997)
    Springer
    Pflügers Archiv 434 (1997), S. 698-704 
    Details
    ISSN: 1432-2013
    Keywords: Key words Hypoxia ; Pulmonary artery ; Carbon monoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Hypoxia activates erythropoietin-producing cells, chemoreceptor cells of the carotid body and pulmonary artery smooth muscle cells (PSMC) with a comparable arterial PO2 threshold of some 70 mmHg. The inhibition by CO of the hypoxic responses in the two former cell types has led to the proposal that a haemoprotein is involved in the detection of the PO2 levels. Here, we report the effect of CO on the hypoxic pulmonary vasoconstriction (HPV). Pulmonary arterial pressure (PAP) was measured in an in situ, blood-perfused lung preparation. PAP in normoxia (20% O2, 5% CO2) was 15.2±1.8 mmHg, and hypoxia (2% O2, 5% CO2) produced a ΔPAP of 6.3±0.4 mmHg. Addition of 8% or 15% CO to the hypoxic gas mixture reduced the ΔPAP by 88.3±2.7% and 78.2±6.1% respectively. The same levels of CO did not affect normoxic PAP nor reduced the ΔPAP produced by angiotensin II. The effect of CO was studied after inhibition of the NO-cyclic guanosine monophosphate (cGMP) cascade with N-methyl-l-arginine (5·10–5 M) or methylene blue (1.4·10–4 M). It was found that both inhibitors more than doubled the hypoxic ΔPAP without altering the effectiveness of CO to inhibit the HPV. In in vitro experiments we verified the inhibition of guanylate cyclase by measuring the levels of cGMP in segments of the pulmonary artery. Cyclic GMP levels were 1.4±0.2 (normoxia), 2.5±0.3 (hypoxia) and 3.3±0.5 pmole/mg tissue (hypoxia plus 8% CO); sodium nitroprusside increased normoxic cGMP levels about fourfold. Methylene blue reduced cGMP levels to less than 10% in all cases, and abolished the differences among normoxic, hypoxic and hypoxic plus CO groups. It is concluded that CO inhibits HPV by a NO-cGMP independent mechanism and it is proposed that a haemoprotein could be involved in O2-sensing in PSMC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050454
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