Effects of immunosuppressive therapy on the rat aortic allograft model.
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Animals↗
Biomedical subjects
J Kowalski
Publications and source records attributed to J Kowalski.
Characterization and applications of the disc angiogenesis system.
A model to study microvascular proliferation, the Disc Angiogenesis System (DAS), consists of a synthetic foam disc implanted subcutaneously in experimental animals. After a period of growth, usually 7 to 21 days, the disc is removed. Planar sections are used to measure and characterize the growth. Microvessels grow centripetally into the disc, together with fibroblasts. Concentric growth zones have been defined by light and electron microscopy. Moderate growth occurs spontaneously and is accelerated by angiogenic stimulants placed in the center of the disc. Morphometric analyses have shown that vessel growth is directly proportional to total fibrovascular growth, so the former can be quantified by procedures measuring the latter. These include manual projection of sections and computer-assisted digital image analysis, which is recommended for routine use. The proliferation of endothelial and other cells is determined by incorporation of tritiated thymidine, using scintillation counting and autoradiography. Using the DAS, well-established angiogenic agents such as basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and prostaglandin E1 were found to increase proliferation of endothelial cells (EC) and microvessels. Heparin augmented the effect of bFGF. When used by itself heparin increased angiogenesis but not EC proliferation, in keeping with in vitro observations indicating that it stimulates migration but not proliferation of EC. Locally applied hyperthermia and ionizing radiation decreased angiogenesis, even when applied after the angiogenic stimulus. Systemic prostaglandin synthetase inhibitors antagonized the angiogenic effects of bFGF and EGF, in accordance with a postulated role of prostaglandins in the transduction of proliferative signals in microvascular EC. The DAS is easy to assemble and implant in small animals, including mice, which tolerate it well. Hence multiple discs can be used for each time or dose point, which allows reproducible measurements of vascular growth and increases statistical accuracy. Another advantage of the system is the capability of discriminating between proliferation and migration of EC and fibroblasts. The DAS can be used to test putative agonists or antagonists of angiogenesis. More generally, the DAS provides a model of wound healing, either uncomplicated or complicated by inflammation, and of angiogenic responses to solid tumors.
Animals↗
Antimicrobial susceptibility of bacterial isolates from 233 horses with musculoskeletal infection during 1979-1989.
Bacterial culture and susceptibility results were analysed from 233 horses with septic arthritis/tenosynovitis or osteomyelitis that developed after fracture repair. Antibiotics were deemed highly effective, effective or ineffective if > or = 85%, 70-84.9% or < 70% of the isolates were susceptible respectively. In total, 424 bacterial types were isolated; 386 were aerobic or facultative and 38 were anaerobic. Enterobacteriaceae (28.8%) were the most common bacterial group isolated, followed by non-beta-haemolytic streptococci (13.0%), coagulase-positive staphylococci (11.8%), beta-haemolytic streptococci (9.4%), and coagulase-negative staphylococci (7.3%). The remainder of the organisms were other Gram-negative (15.8%), other Gram-positive (2.3%) and miscellaneous (2.6%) bacteria. Penicillin and ampicillin were highly effective against beta-haemolytic streptococci, but were ineffective against other bacteria. Ampicillin was no more effective than penicillin against most bacteria. Amikacin was the most effective antibiotic against the wide range of bacteria isolated in this study. Amikacin was highly effective against coagulase-positive staphylococci, Enterobacteriaceae and Pseudomonas and was effective against coagulase-negative staphylococci and Actinobacillus. Gentamycin was not highly effective against any bacterial group; but was effective against coagulase-positive and negative staphylococci, Pseudomonas, Salmonella and Actinobacillus. Kanamycin was ineffective against all bacteria with the exception of Actinobacillus. Cephalothin was highly effective against beta-haemolytic streptococci, coagulase-positive staphylococci and Actinobacillus and was effective against coagulase-negative staphylococci.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Characterization of opioid binding sites in rat spinal cord.
Binding sites were characterized in rat whole spinal cord crude membrane preparations using selective labelling techniques with multiple methods of mathematical analysis of experimental curves. Mathematical analysis of single [3H]-[D-Ala2,MePhe4,Gly-ol5] enkephalin (DAGO) saturation curves suggested binding of the [3H]-ligand at one site, while displacement curves of low concentrations of [3H]-DAGO with selective mu-ligands indicated the presence of high- and low-affinity sites. All the [3H]-DAGO curves processed simultaneously by LIGAND analysis showed the presence of high (27%) and low (73%) affinity components, with a total Bmax of 3.19 pmol/g tissue. Eighty percent of [3H]-[D-Ala2,D-Leu5] enkephalin (DADLE) binding was displaced by DAGO with high affinity, indicating that a high percentage of [3H]-DADLE binding was at mu-sites. Saturation curves of [3H]-DADLE after inhibition of mu-sites by unlabelled DAGO (delta-sites) were monophasic with non-linear fitting analysis and the Bmax was 0.90 pmol/g tissue. Most mathematical analysis of single saturation curves of [3H]-(-)-bremazocine indicated binding at more than one site. DAGO, DADLE, U-69,593 and PD 117302 displaced 0.15 nM of [3H]-(-)-bremazocine biphasically: the percentages of displacement calculated with the non-linear fitting program were respectively 50 (mu-sites), 64 ((mu + delta)-sites), 18 and 25 (kappa-sites). Haloperidol displaced [3H]-(-)-bremazocine only at microM concentrations. suggesting no binding at sigma-sites. In the presence of 225 nM of DAGO, DADLE displaced only 21% of [3H]-(-)-bremazocine 0.15 nM binding (delta-sites). Most mathematical analysis of saturation curves of [3H]-(-)-bremazocine, after inhibition of binding at mu- and delta-sites by DAGO and DADLE, still indicated binding at more than one site and the selective kappa-ligands U-69,593 and PD 117302 displaced [3H]-(-)-bremazocine in these experimental conditions. LIGAND analysis of saturation and inhibition curves of [3H]-(-)-bremazocine by U-69,593 and PD 117302 showed the presence of high (43%) and low (57%) affinity components, with a total Bmax of 2,73 pmol/g tissue. Thus in rat spinal cord there are at least two mu-sites bound by [3H]-DAGO which amount together to approximately 47% of total opioid sites, delta-sites bound by [3H]-DADLE amounting to approximately 13%, kappa-sites and other unknown sites (possibly a kappa-subtype) bound by [3H]-(-)-bremazocine, which together are approximately 40% of total opioid sites.
Animals↗
Dual role of tumor necrosis factor-alpha in angiogenesis.
The role of tumor necrosis factor-alpha (TNF; cachectin) in angiogenesis has been controversial. In vitro TNF inhibits proliferation of endothelial cells (EC) whereas in the cornea it appears to stimulate vessel growth. The authors tested TNF in their recently developed disc angiogenesis system (DAS), designed to measure the proliferation of microvessels. The DAS, implanted subcutaneously in mice, was either fitted with a central pellet containing mouse recombinant TNF (mrTNF), or exposed to mrTNF delivered subcutaneously by an osmotic minipump. Low doses of mrTNF (0.01-1 ng) induced angiogenesis, which was maximum at 0.1 ng, whereas high doses (1, and 5 micrograms) inhibited it. Subcutaneous mrTNF delivered at the (high) rate of 15-60 ng/hr for 14 days inhibited angiogenesis. These results indicate bimodal, dose-dependent opposing effects and explain some of the in vitro versus in vivo paradoxical results. TNF (native or exogenous) may have opposing effects on microvessels of neoplasms and inflammatory reactions, depending on its local tissue concentrations.
Animals↗
Chronic treatment with chlorpromazine, thioridazine or haloperidol increases striatal enkephalins and their release from rat brain.
The aim of this paper is to study the effect of 1, 2 or 3 months' administration of chlorpromazine (CPZ), thioridazine (TDZ) (2 or 6 mg/kg) or haloperidol (HAL) (0.25 or 1 mg/kg) IP on the level of leu- and met-enkephalin (ENK) in striatum. A dose- and time-dependent increase of striatal ENK level was observed after chronic administration of the neuroleptics (NL), but 8 days after withdrawal of chronically administered NL striatal ENK was decreased. Apomorphine pretreatment significantly attenuated the elevation in ENK produced by chronic injections of NL. In perfusion fluid obtained from the lateral ventricle of animals treated 1 month with HAL a dose-dependent increase of ENK levels was observed, which was augmented by potassium ions. It is concluded that: 1) Chronic administration of neuroleptic drugs that block dopamine receptors increases the level and the release of striatal enkephalins; 2) The results support the hypothesis that activation of dopaminergic neurons tonically inhibits the synthesis of enkephalins in the striatum.
Animals↗
Deoxyadenosine- and cyclic AMP-induced cell cycle arrest and cytotoxicity.
We compared deoxyadenosine (AdR)- and cyclic AMP (cAMP)-induced cell cycle arrest and cytotoxicity in wild type and mutant S49 cells to determine whether they resulted from the same or different mechanisms. Cyclic AMP and deoxyadenosine are synergistic rather than additive in cytotoxicity assays, suggesting different mechanisms of toxicity. Although cyclic AMP causes cell death after 72 h, in concentrations sufficient to result in cell cycle arrest it is reversible with virtually no cytotoxicity for at least 24 h, whereas AdR-induced cell cycle arrest is lethal and irreversible. AdR-induced G1 cell cycle arrest results in diminished ribonucleotide reductase activity but the kinetics of this inhibition differ from cyclic AMP-induced cell cycle arrest. Cyclic AMP arrest and cytotoxicity depend on cyclic AMP-dependent protein kinase (PKA) activity, whereas AdR toxicity does not differ between cell lines with or without PKA activity. Furthermore, deoxycytidine prevents AdR cell cycle arrest and cytotoxicity but has no effect on cyclic AMP G1 arrest. Finally, comparison of cytofluorographic patterns of G1-arrested cells suggests that the AdR block is later in G1 than cyclic AMP-induced cell cycle arrest. In summary, these data show that while the mechanisms of cell cycle arrest and cytotoxicity of cyclic AMP and deoxyadenosine are uncertain, they do appear to involve different pathways.
Cell Cycle↗
Effect of interval between doses on response of the pony to sodium bicarbonate.
Three pony geldings were given sodium bicarbonate orally in order to study the effect on blood pH and bicarbonate and to determine if frequency of dosing influences the response. In a preliminary study, it appeared that a carry-over effect might occur if the interval between dosing was only 2 days. The ponies received 2 doses of sodium bicarbonate (400 mg/kg) 7 days apart in trial one and then in trial two they received 2 doses of sodium bicarbonate 4 days apart. The sodium bicarbonate was mixed with 2 liters of warm water and given through a nasogastric tube on each trial day. Blood samples were taken before dosing, and every half hour after for five and a half hours. The blood was analyzed for pH and bicarbonate. There did not seem to be a carry-over effect due to sodium bicarbonate administration since there was little difference in the responses between the first and second doses of each trial.
Animals↗
The dose dependent effect of cyclic AMP on ribonucleotide reductase in mitogen stimulated mononuclear cells.
Cyclic adenosine monophosphate arrests proliferating T lymphocytes in the G1 phase of the cell cycle. Here we demonstrate that exogenous and endogenous elevations in cyclic AMP concentration result in diminished mitogen stimulation, cell cycle arrest, and decreased ribonucleotide reductase messenger RNA concentrations in peripheral blood mononuclear cells. At lower concentrations (less than 1mM) of dibutyryl cyclic AMP that do not generate cell cycle arrest there is inhibition of ribonucleotide reductase activity without decreased messenger RNA concentration for the M2 subunit of ribonucleotide reductase. However, at higher concentrations of dibutyryl cyclic AMP there is G1 cell cycle arrest and reduced M2 specific messenger RNA concentration. Thus, cyclic AMP inhibition of lymphocyte activation may occur by different mechanisms that are dose dependent.
4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
Effect of cyclic AMP on the cell cycle regulation of ribonucleotide reductase M2 subunit messenger RNA concentrations in wild-type and mutant S49 T lymphoma cells.
Ribonucleotide reductase activity in S49 T lymphoma cells is cell cycle regulated by de novo protein synthesis of the M2 subunit. There is maximal enzyme activity in S and G2/M phase with low activity and low concentrations of the M2 subunit in G1 phase. Pharmacologic concentrations of cyclic AMP arrest S49 cells in the G1 phase of the cell cycle. We investigated the effect of cyclic AMP on M2 messenger RNA concentrations using RNA from exponentially growing and elutriated, cell cycle-enriched populations. To discern whether cyclic AMP-induced G1 arrest was associated with low concentrations of M2-specific messenger RNA, we probed blots with a full-length cDNA for M2. Cell cycle variation in M2 messenger RNA concentrations was similar in wild-type, hydroxyurea-resistant cells with amplified M2 activity, and cyclic AMP-dependent protein kinase-deficient cell lines. All lines had low amounts of M2-specific mRNA in early G1, an increase at the late G1/early S phase interface, a decrease in mid S phase, and another increase in late S phase that continued through G2/M. These concentrations did not directly correlate with enzyme activity, suggesting other regulatory effects might participate in determining ribonucleotide reductase activity. Cyclic AMP exposure appeared to induce cell cycle arrest in early G1 with low M2-specific messenger RNA concentration. This effect reversed upon washout of the cyclic AMP and was dependent on functional cyclic AMP-dependent protein kinase (PKA). These results suggest that cyclic AMP arrests S49 mouse T lymphoma cells in early G1 prior to transcriptional activation of the M2 gene.
Animals↗
Effects of X irradiation on angiogenesis.
We have evaluated the effect of X irradiation on the mesenchymal tissue growth (blood capillaries and stromal cells) in an angiogenesis system in the mouse. This was accomplished by implanting a polyvinyl alcohol sponge disc in the subcutis of the thorax, and quantifying the extent of growth reduction of capillaries and stromal cells following graded doses of X rays. The sponge disc contained a centrally located pellet impregnated with 20 micrograms of epidermal growth factor and coated with a thin film of slow-releasing compound. Total growth of vessels and fibroblasts was determined by morphometric analysis of histologic sections. The incorporation of [3H]TdR was measured during a 24-h period. A dose-response relationship was observed when X irradiation was given on Day 11 after implantation, with the disc removed on Day 20. A single dose of 15 Gy reduced both the rate of incorporation of [3H]TdR and the total growth area. These and previous observations point to endothelial cells as important targets of ionizing radiation in the stroma, especially during the period of active proliferation of these cells, induced by growth factors.
Animals↗
[The aftercare findings and recall behavior of older patients with removable dentures].
Data were collected from 285 patients (average: 63.8, range: 23 to 87) who received prosthodontic treatment at the Clinic for Removable Prosthodontics of the University of Bern during the years of 1981 through 1987. 62 edentulous patients received two osseointegrated implants in the lower jaw. For the partially edentulous patients, removable partial dentures (RPD-89 patients) or overdentures (OD-134 patients) were prescribed. These two groups received recall care for a period of 2 to 3 years after insertion of the dentures. Due to limited capacity of the university clinics, a great part of these patients were then referred to private practitioners. All patients from the student course, however, were carefully checked during the year after insertion of the denture. Implant patients received a regular recall throughout the observation time. The patients' behaviour was not up to the dentists' expectations: less than 50% of the RPD and OD patients followed the recall appointment regularly. In contrast, the implant patients participated 100% in the recall. The plaque and bleeding indexes were much higher in the partially edentulous than in the implant patients. RPD and OD patients with regular recalls scored significantly better, but never reached the same level of results as the implant patients. Nevertheless, the probing depths on implants were a bit higher compared to those of the natural teeth, but not significantly.
Adult↗
Nontyphoid Salmonella carrier state treated with norfloxin.
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Adult↗
Regulation of the mRNA for monocyte-derived neutrophil-activating peptide in differentiating HL60 promyelocytes.
A cDNA library was constructed from HL60 human promyelocyte poly(A)+ RNA harvested 3 h after induction of macrophage differentiation with 12-O-tetradecanoyl phorbol-13-acetate in the presence of cycloheximide. We isolated from this library a 1.6-kilobase full-length clone designated b4 whose corresponding mRNA was greatly increased in abundance in cytoplasmic RNA under these conditions. Dideoxy sequencing revealed that this mRNA encoded MONAP (monocyte-derived neutrophil-activating peptide), a 10-kilodalton monokine with neutrophil-specific chemotactic and enzyme-releasing activities. The 3' untranslated region of this mRNA was found to be 1.2 kilobases long and possessed nine copies of the AUUUA sequence known to be associated with regulation of mRNA stability. Actinomycin D chase experiments yielded evidence that cytoplasmic stabilization was one of the means of regulation of MONAP expression. Analysis of cytoplasmic poly(A)- RNA revealed the presence of several discrete truncated species that shared a common 5' end and appeared to be intermediates of degradation. S1 mapping showed that the 3' ends of these molecules were distributed throughout the 3' untranslated region, preferentially in A + U-rich regions, broadly correlating with the distribution of AUUUA sites. Nuclear run-on experiments indicated that transcriptional induction accounted for less than 15% of the accumulation of MONAP mRNA. This mRNA was induced in HL60 cells by treatment with several differentiation-inducing agents: 12-O-tetradecanoyl phorbol-13-myristate alone, sodium butyrate, vitamin D3, and dimethyl sulfoxide. It was also induced in quiescent diploid lung fibroblasts stimulated to divide by serum, and it was constitutively overexpressed by some human tumor lines.
Amino Acid Sequence↗
[Functional status of the respiratory system in patients with short- and long-term remission of bronchial asthma].
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Asthma↗
[Partial oxygen pressure in arterialized capillary blood of the skin in allergic bronchial spasm].
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Adult↗
Specialized plasmid vectors for cloning cDNA.
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Cloning, Molecular↗
Hyperthermia inhibits angiogenesis.
Since in vitro studies have demonstrated that capillary endothelial cells are thermosensitive, experiments were performed to determine the (in vivo) heat sensitivity of blood capillaries and their endothelial cells. Angiogenesis discs were implanted subcutaneously in mice, and vascular growth was stimulated by slow release of epidermal growth factor placed in the center of each disc. After 5 days of growth the discs were subjected to radiofrequency-induced hyperthermia. Heat exposures were 41, 42, 43, and 44 degrees C for 30 min. Control discs were sham treated. Seven days after heating the discs were extracted and paraffin embedded. Centripetal (radial) vessel growth was measured in magnified medial planar sections. An inverse relationship was demonstrated between vessel growth and exposure temperature. The extent of the fibroblastic growth was also inversely proportional to temperature. Thus, at least in this system, the microvasculature shows dose-dependent damage by hyperthermia, consistent with preceding in vitro observations. This inhibition of angiogenesis may result from endothelial cell killing, interference with cell replication, inhibition of cell migration, or a combination of these mechanisms.
Animals↗