Cells obtained from bronchoalveolar lavage, or neutrophils of peripheral blood of dog, were incubated with the canine surfactant-associated protein A (SP-A). A significant decrease of the production of superoxide anion was observed after subsequent stimulation with phorbol-12-myristate-13-acetate (PMA) as measured by the lucigenin-dependent chemiluminescence (CL). Several other proteins used for control experiments did not decrease lucigenin-dependent CL, indicating a specific effect of SP-A on phagocytes. Treatment of SP-A with collagenase prior to incubation with neutrophils destroyed the depleting effect on oxygen radical production of PMA-stimulated cells. We propose that SP-A acts as a regulatory factor of the respiratory burst of alveolar macrophages and neutrophils in the lungs. The inhibitory effect of SP-A is down-regulated by collagenase released from stimulated alveolar macrophages.

Acridines↗

PubMed1990

Evidence for a role of translational frameshifting in the expression of transposition activity of the bacterial insertion element IS1.

The bacterial insertion element IS1 contains two essential open reading frames, insA and insB, arranged in tandem. We have introduced a number of site-specific mutations into the region including the 3'-terminal region of insA, the region between insA and insB, and the ATG codon at the start of insB. Relative transposition activities of mutant and wild-type elements were determined using a modified in vivo cointegration assay. The results support the hypothesis that a translational (-1) frameshift occurring in the 3'-terminal region of insA and linking insB to insA is responsible for the synthesis of the active IS1 transposition enzyme. Further results with IS1 elements containing internal deletions are in agreement with a role of the normally terminated insA product as an inhibitor of transposition.

Amino Acid Sequence↗

PubMed1990

Determination of a cytostatic agent, bendamustine, in plasma using capillary gas chromatography with nitrogen-selective detection.

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Animals↗

PubMed1990

Cytofluorometric and cytomorphologic analysis of human bone marrow cells derived from stromal cultures stimulated by granulocyte-macrophage colony-stimulating factor, interferon-gamma and splenopentin pentapeptide.

We studied the influence of human recombinant granulocyte-macrophage colony-stimulating factor (hrGM-CSF), human recombinant interferon-gamma (hrIFN-gamma) and splenopentin pentapeptide (Sp-5), either alone or in combination, on the proliferation and differentiation of human bone marrow cells in modified Dexter's cultures. After 10, 14 and 21 days cells were analyzed by classical staining according to Pappenheim and by cytofluorometry with a set of different monoclonal antibodies. IFN-gamma inhibited the proliferation of progenitor cells and provided signals promoting monocytic differentiation, whereas GM-CSF induced the proliferation of blastoid elements which expressed HLA-DR and M2 (VIM-2 monoclonal antibody), but progressively lost surface CD34. Furthermore, an increase of CD15+ cells was also observed. When GM-CSF was tested in combination with IFN-gamma, it abolished the inhibitory effect of IFN-gamma and both cytokines synergized to promote the expression of CD11c, CD14 and M2 surface antigens. Sp-5 alone had only a marginal activity, but it potentiated the effects of GM-CSF. These findings suggest that GM-CSF may induce the transition from stem cells to committed myeloid progenitors. In contrast to IFN-gamma, Sp-5 can serve as an additional proliferative signal with negligible effects on cell maturation.

Amino Acid Sequence↗

PubMed1990

Two-dimensional electrophoresis of dog bronchoalveolar lavage fluid proteins.

Proteins of dog bronchoalveolar lavage fluid, obtained by washing the epithelial lining layer of lungs with phosphate-buffered saline, were separated by two-dimensional electrophoresis. Due to the low protein and high salt content of the bronchoalveolar lavage fluid, samples had to be concentrated and desalted. Following electrophoresis the protein spots were visualized by silver staining. Comparing the two-dimensional protein patterns of bronchoalveolar lavage fluid with that from serum, several lung-specific proteins were detected. The most prominent protein, most probably a surfactant-associated protein, showed isoforms with isoelectric points in the range of pH 4.2-4.8, and a molecular mass of 32 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis after reduction with dithiothreitol.

Animals↗

PubMed1990

In vitro DNA methylation inhibits gene expression in transgenic tobacco.

A hemimethylated chimeric gene, containing the cauliflower mosaic virus 35S promoter, the beta-glucuronidase coding region and the polyadenylation signal of nopaline synthase, was introduced into tobacco protoplasts by polyethylene glycol mediated transfection. Hemimethylation led to complete inhibition of transient gene expression. In regenerated transgenic plants the integrated gene was constitutively hypermethylated at the sequences CpG and CpNpG and this was correlated with an inactivation of beta-glucuronidase in 12 out of 18 analyzed plant lines whereas two showed slight and four strong activity. From 10 control lines transformed with nonmethylated DNA, only two were inactive; three showed slight and five strong activity. 5-aza-cytidine treatment of plant tissue from 'hypermethylated' lines led to induction of beta-glucuronidase in most cases. Shoots regenerated from azaC treated calli revealed stable enzyme restoration and demethylation of the integrated transgene.

Amino Acid Oxidoreductases↗

PubMed1990

Laser balloon angioplasty: technical realization and vascular tissue effects of a modified concept.

A modified concept using a movable fiber with radial light dispersion was developed for combining mechanical balloon dilatation and intraluminal circumferential Nd-Yag laser irradiation of the arterial wall. The aims of the study were the technical feasibility and the acute and chronic vascular tissue effects of laser-assisted balloon dilatation. The carotid arteries (n = 9 dogs) and femoral arteries (n = 5 dogs) of dogs were mechanically dilated and simultaneously circumferentially irradiated through the balloon by 1,064 nm Nd-Yag laser (20-25 W). Temperature at the adventitial surface was kept constant at 50 degrees C, 60 degrees C, 70 degrees C, or 80 degrees C for either 8 or 15 seconds by a computerized feedback system for temperature control. Angiographic and histological results were available acutely, subacutely (2 days), and at 3 months. Angiographically, stable and smooth enlargement of the lumen was demonstrated acutely. At 3 months, occlusions, probably thrombotic in origin, had occurred in 5 of the carotid arteries and none of the femoral arteries. Histologically, laser-induced coagulation of the arterial wall with loss of cellular elements was demonstrated. Collagen and elastic fibers remained relatively intact. In two carotid arteries intimal proliferation was observed at the treated site. Thus, this technique appears to be technically feasible, yet further study is needed to assess its potential to reduce or repair acute vascular complications (dissections) and to reduce restenoses after percutaneous transluminal coronary angioplasty (PTCA). However, the clinical value of this technique appears to be limited in view of the thromboses and reactive proliferations observed in this preliminary study.

Angioplasty, Balloon↗

PubMed1990

Effects of Nd: YAG laser coagulation of myocardium on coronary vessels.

Laser coagulation of arrhythmogenic myocardium proved to be an effective surgical therapy for refractory arrhythmias. To determine the influence of Nd: YAG laser coagulation of myocardium on coronary vessels, a total of 48 transcatheter laser impacts (10 W, 10 sec, 7 W mm2) were directed to the left ventricular free wall via endocardial (24 lesions in 2 dogs) or epicardial (24 lesions in 2 dogs) approach. In 8 of 24 endomyocardial lesions (2 and 6 months old) coronary vessels with a diameter of greater than 50 microns were found within the coagulation zones. The volume of these lesions was significantly (P less than 0.01) smaller (139 +/- 43 mm3) than those (n = 16) with coronary vessels measuring less than 50 microns (311 +/- 87 mm3). Volumes of epimyocardial lesions (1-2 hours old) produced by transcoronary irradiation with normal coronary blood flow were significantly (P less than 0.01) smaller (31 +/- 17 mm3) than with reduced (73 +/- 22) or interrupted (119 +/- 34 mm3) blood flow (n = 8, each). Both directly irradiated coronary vessels and those found within the coagulation zones and scars appeared histologically normal through all layers with an intact intima without fibrosis or thrombosis. The ultrastructure of irradiated arteries, even with total interruption of blood flow, was no different from that of non-irradiated controls. Thus, coronary artery blood flow significantly reduces the volume of coagulated myocardium, whereas the vessels themselves appear to remain undamaged by laser irradiation as used for myocardial coagulation.

Animals↗

PubMed1990

Effect of a local ibotenic acid lesion in the visual association area on the prelunate gyrus (area V4) on saccadic reaction times in trained rhesus monkeys.

Two rhesus monkeys were trained to make saccadic eye movements from a central fixation point towards a peripheral target. Saccadic reaction times (SRTs) were measured in the gap paradigm (200 ms pause between offset of fixation point and onset of peripheral target). Target position for extensive training (SRTs of 150 to 250 saccades were collected per day) was four degrees eccentric in the lower quadrant of the visual field contralateral to the intended lesion site in area V4. For control the monkeys were also trained for target positions either in the lower quadrant ipsilateral to the intended lesion site or in the upper visual half field. After several weeks of training a bimodal distribution of saccadic reaction times, one peak at 85 ms (express saccades) and the other around 160 ms (regular saccades) was obtained for each target position. Local injection of ibotenic acid into the 4 deg representation of area V4 resulted in a unimodal distribution of saccadic reaction times (over 90% express saccades) towards the corresponding target position, leaving the distribution of reaction times for the control position unchanged. Recovery began after 5 days and was complete 8 to 10 days after the injection. From these results we conclude that V4 is involved in the generation of the longer latency peak in the distribution of saccadic reaction times by delaying the initiation of visually guided saccades.

Animals↗

PubMed1990

Infusion of nifedipine after coronary artery bypass grafting decreases the incidence of early postoperative myocardial ischemia.

We performed a randomized study on patients undergoing elective coronary bypass grafting to examine whether postoperative infusion of nifedipine (n = 25) could reduce the incidence of isolated transient myocardial ischemia, myocardial infarction, or both. The control group (n = 25) received nitroglycerin. Hemodynamic and Holter monitoring and serial assessment of enzymatic and electrocardiographic changes were performed for all patients. Both groups showed comparable preoperative and operative data. The incidence of myocardial infarction was significantly lower in the nifedipine group (n = 1) as compared with the control group (n = 4), whereas the number of patients with isolated transient myocardial ischemia was similar in both groups (nifedipine, 3; control, 4). At the time of peak activity, levels of creatine kinase (350 +/- 129 versus 511 +/- 287 IU/mL), creatine kinase-MB (8.4 +/- 5.4 versus 17.1 +/- 11.0 IU/mL), and glutamate-oxaloacetate-transaminase (30.4 +/- 4.4 versus 41.0 +/- 7.9 IU/mL) were markedly lower in the nifedipine group (p less than 0.05). We conclude that infusion of nifedipine after elective coronary artery bypass grafting effectively decreases the incidence of myocardial infarction and the extent of myocardial necrosis during the early postoperative period.

Blood Pressure↗

PubMed1990

Splenopentin (DAc-SP5)--influence on engraftment and graft-vs-host reaction after non-H-2 bone marrow transplantation in mice.

The influence of DAc-SP5 on engraftment and graft-vs-host reaction (GVHR) was studied in different non-H-2 strain combinations. The engraftment was more or less enhanced in every case, whereas the situation in the GVHR was completely different. In one case splenopentin did not influence the course of the GVHR so much, in a second case the symptoms of the GVHR were completely abolished, and in a third case the GVHR was dramatically enhanced up to a great mortality. Therefore, before application of DAc-SP5 to the bone marrow transplantation in humans in order to improve the engraftment, parameters have to be found which allow an exact prediction about the influence of splenopentin on the GVHR in each single case.

Animals↗

PubMed1990

Saccadic reaction times of dyslexic and age-matched normal subjects.

Saccadic reaction times (SRT) were measured in a simple task: subjects had to make saccades from a central fixation point to peripheral targets, which appeared randomly 4 deg to the left or to the right. In the first test the fixation point went off before the target appeared (gap trials); in the second test it remained on the screen (overlap trials). The distribution of SRTs for trained normal adults (N = 4), untrained normal adults (N = 11), untrained normal children (aged 9-11 years, N = 9), untrained normal teenagers (aged 15-17 years, N = 8), dyslexic children (aged 9-11 years, N = 15), and dyslexic teenagers (aged 15-17 years, N = 5) were compared, with special emphasis on the number of express saccades, ie saccades with extremely short reaction times (100-120 ms, under the present conditions). In normal adults with the gap paradigm, the distribution of reaction times typically exhibits two or three modes (express saccades, fast regular saccades, and very few slow regular saccades), whereas in the overlap paradigm only one or two modes (few fast regular saccades and many slow regular saccades) are obtained. On average, normal children produce more express saccades than naive normal adults. Dyslexic children produce more express saccades than the normal age-matched controls. Among the dyslexic children, four different types of abnormalities in their reaction times were encountered. The group of dyslexic teenagers was characterized by a larger number of express saccades at the expense of fast regular saccades in gap trials and by fewer express saccades and fewer fast regular saccades in overlap trials when compared to the age-matched control group. It is concluded that the abnormal patterns of saccadic reaction times reflect defects in the system of visual attention and/or in its control over the oculomotor system, rather than indicating a defect in the oculomotor system itself. In this context, symptoms of dyslexia appear as a combination of attentional deficits and irregular timing of saccadic eye movements.

Adolescent↗

PubMed1990

Dietary protein restriction stress and adrenocortical function: evidence for transient and long-term induction of enhanced cellular function.

Previous work has demonstrated that 4-week protein restriction of the domestic fowl (Gallus gallus domesticus) increases both adrenocortical cell sensitivity to ACTH and corticosteroidogenic capacity. In the present study we examined the transience (study 1) and the persistence (study 2) of this effect of protein restriction. In study 1, two strains of domestic fowl were used: a slower-growing White Leghorn strain and a faster-growing Cobb broiler strain. Cockerels (2 weeks old) were fed isocaloric diets containing either low (L; 5% or 8%) or control (C; 20%) levels of soy protein for 2 weeks, and then were either switched to the alternate diet (C-L, L-C) or maintained on the initial diet (C-C, L-L) for an additional 2 weeks. Cockerels were killed at 6 weeks of age. In study 2, White Leghorn cockerels (2 weeks old) were fed either diet for 4 weeks and then switched to or maintained on the control diet for an additional 4 weeks (i.e. C vs. restriction followed by repletion). In this study cockerels were killed at 10 weeks of age. In both studies highly enriched populations of adrenocortical cells were isolated from cockerel adrenal glands, and their steroidogenic properties (basal and maximally induced corticosterone and cAMP production; steroidogenic agent ED50 values) were evaluated in 2-h suspension incubations. In study 1, regardless of strain, the greater the length of the restriction period, the greater the magnitude of maximal cellular corticosterone production induced by ACTH; the average value for 4-week restriction (L-L) was 39.5% greater than that for 2-week restriction (L-C, C-L) and 117.5% greater than that for control (C-C). In addition, the value for restriction from 4-6 weeks of age (C-L) was 34% greater than that for restriction from 2-4 weeks of age (L-C), suggesting that the enhancement of maximal ACTH-induced corticosterone production after a 2-week restriction interval might be transient. Although there were no strain differences in the effect of protein restriction on maximal ACTH-induced corticosterone production, there were strain differences in its effect on cellular sensitivity to ACTH, as indicated by the ACTH ED50 values (the lower the ED50 value, the greater tha cellular sensitivity). With the White Leghorn strain, the greater the duration of protein restriction, the greater the adrenocortical cell sensitivity to ACTH; the sensitivity of L-L cells was 3.0 times the sensitivities of L-C and C-L cells and 4.1 times the sensitivity of C-C cells.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1990

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria, X. Analysis of structural elements responsible for the differences in thermostability and activation by fructose 1,6-bisphosphate in the lactate dehydrogenases from B. stearothermophilus and B. caldolyticus by protein engineering.

The amino-acid sequences of the lactate dehydrogenases (LDH) from B. stearothermophilus and B. caldolyticus differ at only 10 positions. The properties of these enzymes however show substantial differences. The LDH from B. stearothermophilus is activated by Fru-P2 and has a higher thermostability (10 degrees C) than the enzyme from B. caldolyticus which cannot be activated by Fru-P2. To correlate these functional differences to the structural properties, we have constructed a set of hybrid- and point-mutants of the two LDHs. The amino acids at positions 207, 209B, and 209C could be identified to confer the property of activation by Fru-P2 to the enzymes. This part of the enzyme is to a large extent also responsible for the different thermostabilities of these two proteins.

Amino Acid Sequence↗